* [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups
@ 2022-02-03 11:08 Florian Weimer
2022-02-03 11:08 ` [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version Florian Weimer
` (4 more replies)
0 siblings, 5 replies; 30+ messages in thread
From: Florian Weimer @ 2022-02-03 11:08 UTC (permalink / raw)
To: libc-alpha
This removes some support code for pre-2.4.0 kernels and Native Client.
Tested on i686-linux-gnu and x86_64-linux-gnu. Built with
build-many-glibcs.py.
v2: Rebased on current trunk.
Florian Weimer (5):
elf: Merge dl-sysdep.c into the Linux version
Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE
Linux: Remove DL_FIND_ARG_COMPONENTS
Linux: Assume that NEED_DL_SYSINFO_DSO is always defined
Linux: Consolidate auxiliary vector parsing
elf/dl-support.c | 80 +----
elf/dl-sysdep.c | 352 +------------------
sysdeps/unix/sysv/linux/alpha/dl-auxv.h | 18 +-
sysdeps/unix/sysv/linux/dl-parse_auxv.h | 61 ++++
sysdeps/unix/sysv/linux/dl-sysdep.c | 240 ++++++++++++-
sysdeps/unix/sysv/linux/ldsodefs.h | 12 -
sysdeps/unix/sysv/linux/m68k/sysdep.h | 4 +-
sysdeps/unix/sysv/linux/powerpc/dl-auxv.h | 14 +-
sysdeps/unix/sysv/linux/powerpc/dl-support.c | 4 +
9 files changed, 305 insertions(+), 480 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/dl-parse_auxv.h
create mode 100644 sysdeps/unix/sysv/linux/powerpc/dl-support.c
base-commit: e8faf48321aa47f7d5e4690acf051db3d98467d7
--
2.34.1
^ permalink raw reply [flat|nested] 30+ messages in thread* [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version 2022-02-03 11:08 [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups Florian Weimer @ 2022-02-03 11:08 ` Florian Weimer 2022-02-08 20:09 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE Florian Weimer ` (3 subsequent siblings) 4 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-03 11:08 UTC (permalink / raw) To: libc-alpha The generic version is the de-facto Linux implementation. It requires an auxiliary vector, so Hurd does not use it. --- elf/dl-sysdep.c | 352 +--------------------------- sysdeps/unix/sysv/linux/dl-sysdep.c | 347 ++++++++++++++++++++++++++- 2 files changed, 337 insertions(+), 362 deletions(-) diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c index f1dba8ef24..7aa90ad6ee 100644 --- a/elf/dl-sysdep.c +++ b/elf/dl-sysdep.c @@ -1,4 +1,4 @@ -/* Operating system support for run-time dynamic linker. Generic Unix version. +/* Operating system support for run-time dynamic linker. Stub version. Copyright (C) 1995-2022 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -16,352 +16,4 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -/* We conditionalize the whole of this file rather than simply eliding it - from the static build, because other sysdeps/ versions of this file - might define things needed by a static build. */ - -#ifdef SHARED - -#include <assert.h> -#include <elf.h> -#include <errno.h> -#include <fcntl.h> -#include <libintl.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <sys/mman.h> -#include <ldsodefs.h> -#include <_itoa.h> -#include <fpu_control.h> - -#include <entry.h> -#include <dl-machine.h> -#include <dl-procinfo.h> -#include <dl-osinfo.h> -#include <libc-internal.h> -#include <tls.h> - -#include <dl-tunables.h> -#include <dl-auxv.h> -#include <dl-hwcap-check.h> - -extern char **_environ attribute_hidden; -extern char _end[] attribute_hidden; - -/* Protect SUID program against misuse of file descriptors. */ -extern void __libc_check_standard_fds (void); - -int __libc_enable_secure attribute_relro = 0; -rtld_hidden_data_def (__libc_enable_secure) -/* This variable contains the lowest stack address ever used. */ -void *__libc_stack_end attribute_relro = NULL; -rtld_hidden_data_def(__libc_stack_end) -void *_dl_random attribute_relro = NULL; - -#ifndef DL_FIND_ARG_COMPONENTS -# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ - do { \ - void **_tmp; \ - (argc) = *(long int *) cookie; \ - (argv) = (char **) ((long int *) cookie + 1); \ - (envp) = (argv) + (argc) + 1; \ - for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ - continue; \ - (auxp) = (void *) ++_tmp; \ - } while (0) -#endif - -#ifndef DL_STACK_END -# define DL_STACK_END(cookie) ((void *) (cookie)) -#endif - -ElfW(Addr) -_dl_sysdep_start (void **start_argptr, - void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, - ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) -{ - const ElfW(Phdr) *phdr = NULL; - ElfW(Word) phnum = 0; - ElfW(Addr) user_entry; - ElfW(auxv_t) *av; -#ifdef HAVE_AUX_SECURE -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ -# define set_seen_secure() ((void) 0) -#else - uid_t uid = 0; - gid_t gid = 0; - unsigned int seen = 0; -# define set_seen_secure() (seen = -1) -# ifdef HAVE_AUX_XID -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ -# else -# define M(type) (1 << (type)) -# define set_seen(tag) seen |= M ((tag)->a_type) -# endif -#endif -#ifdef NEED_DL_SYSINFO - uintptr_t new_sysinfo = 0; -#endif - - __libc_stack_end = DL_STACK_END (start_argptr); - DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ, - GLRO(dl_auxv)); - - user_entry = (ElfW(Addr)) ENTRY_POINT; - GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ - - /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ - _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), - "CONSTANT_MINSIGSTKSZ is constant"); - GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; - - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++)) - switch (av->a_type) - { - case AT_PHDR: - phdr = (void *) av->a_un.a_val; - break; - case AT_PHNUM: - phnum = av->a_un.a_val; - break; - case AT_PAGESZ: - GLRO(dl_pagesize) = av->a_un.a_val; - break; - case AT_ENTRY: - user_entry = av->a_un.a_val; - break; -#ifndef HAVE_AUX_SECURE - case AT_UID: - case AT_EUID: - uid ^= av->a_un.a_val; - break; - case AT_GID: - case AT_EGID: - gid ^= av->a_un.a_val; - break; -#endif - case AT_SECURE: -#ifndef HAVE_AUX_SECURE - seen = -1; -#endif - __libc_enable_secure = av->a_un.a_val; - break; - case AT_PLATFORM: - GLRO(dl_platform) = (void *) av->a_un.a_val; - break; - case AT_HWCAP: - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; - break; - case AT_HWCAP2: - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; - break; - case AT_CLKTCK: - GLRO(dl_clktck) = av->a_un.a_val; - break; - case AT_FPUCW: - GLRO(dl_fpu_control) = av->a_un.a_val; - break; -#ifdef NEED_DL_SYSINFO - case AT_SYSINFO: - new_sysinfo = av->a_un.a_val; - break; -#endif -#ifdef NEED_DL_SYSINFO_DSO - case AT_SYSINFO_EHDR: - GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; - break; -#endif - case AT_RANDOM: - _dl_random = (void *) av->a_un.a_val; - break; - case AT_MINSIGSTKSZ: - GLRO(dl_minsigstacksize) = av->a_un.a_val; - break; - DL_PLATFORM_AUXV - } - - dl_hwcap_check (); - -#ifndef HAVE_AUX_SECURE - if (seen != -1) - { - /* Fill in the values we have not gotten from the kernel through the - auxiliary vector. */ -# ifndef HAVE_AUX_XID -# define SEE(UID, var, uid) \ - if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () - SEE (UID, uid, uid); - SEE (EUID, uid, euid); - SEE (GID, gid, gid); - SEE (EGID, gid, egid); -# endif - - /* If one of the two pairs of IDs does not match this is a setuid - or setgid run. */ - __libc_enable_secure = uid | gid; - } -#endif - -#ifndef HAVE_AUX_PAGESIZE - if (GLRO(dl_pagesize) == 0) - GLRO(dl_pagesize) = __getpagesize (); -#endif - -#ifdef NEED_DL_SYSINFO - if (new_sysinfo != 0) - { -# ifdef NEED_DL_SYSINFO_DSO - /* Only set the sysinfo value if we also have the vsyscall DSO. */ - if (GLRO(dl_sysinfo_dso) != 0) -# endif - GLRO(dl_sysinfo) = new_sysinfo; - } -#endif - - __tunables_init (_environ); - - /* Initialize DSO sorting algorithm after tunables. */ - _dl_sort_maps_init (); - -#ifdef DL_SYSDEP_INIT - DL_SYSDEP_INIT; -#endif - -#ifdef DL_PLATFORM_INIT - DL_PLATFORM_INIT; -#endif - - /* Determine the length of the platform name. */ - if (GLRO(dl_platform) != NULL) - GLRO(dl_platformlen) = strlen (GLRO(dl_platform)); - - if (__sbrk (0) == _end) - /* The dynamic linker was run as a program, and so the initial break - starts just after our bss, at &_end. The malloc in dl-minimal.c - will consume the rest of this page, so tell the kernel to move the - break up that far. When the user program examines its break, it - will see this new value and not clobber our data. */ - __sbrk (GLRO(dl_pagesize) - - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1))); - - /* If this is a SUID program we make sure that FDs 0, 1, and 2 are - allocated. If necessary we are doing it ourself. If it is not - possible we stop the program. */ - if (__builtin_expect (__libc_enable_secure, 0)) - __libc_check_standard_fds (); - - (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv)); - return user_entry; -} - -void -_dl_sysdep_start_cleanup (void) -{ -} - -void -_dl_show_auxv (void) -{ - char buf[64]; - ElfW(auxv_t) *av; - - /* Terminate string. */ - buf[63] = '\0'; - - /* The following code assumes that the AT_* values are encoded - starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values - close by (otherwise the array will be too large). In case we have - to support a platform where these requirements are not fulfilled - some alternative implementation has to be used. */ - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av) - { - static const struct - { - const char label[22]; - enum { unknown = 0, dec, hex, str, ignore } form : 8; - } auxvars[] = - { - [AT_EXECFD - 2] = { "EXECFD: ", dec }, - [AT_EXECFN - 2] = { "EXECFN: ", str }, - [AT_PHDR - 2] = { "PHDR: 0x", hex }, - [AT_PHENT - 2] = { "PHENT: ", dec }, - [AT_PHNUM - 2] = { "PHNUM: ", dec }, - [AT_PAGESZ - 2] = { "PAGESZ: ", dec }, - [AT_BASE - 2] = { "BASE: 0x", hex }, - [AT_FLAGS - 2] = { "FLAGS: 0x", hex }, - [AT_ENTRY - 2] = { "ENTRY: 0x", hex }, - [AT_NOTELF - 2] = { "NOTELF: ", hex }, - [AT_UID - 2] = { "UID: ", dec }, - [AT_EUID - 2] = { "EUID: ", dec }, - [AT_GID - 2] = { "GID: ", dec }, - [AT_EGID - 2] = { "EGID: ", dec }, - [AT_PLATFORM - 2] = { "PLATFORM: ", str }, - [AT_HWCAP - 2] = { "HWCAP: ", hex }, - [AT_CLKTCK - 2] = { "CLKTCK: ", dec }, - [AT_FPUCW - 2] = { "FPUCW: ", hex }, - [AT_DCACHEBSIZE - 2] = { "DCACHEBSIZE: 0x", hex }, - [AT_ICACHEBSIZE - 2] = { "ICACHEBSIZE: 0x", hex }, - [AT_UCACHEBSIZE - 2] = { "UCACHEBSIZE: 0x", hex }, - [AT_IGNOREPPC - 2] = { "IGNOREPPC", ignore }, - [AT_SECURE - 2] = { "SECURE: ", dec }, - [AT_BASE_PLATFORM - 2] = { "BASE_PLATFORM: ", str }, - [AT_SYSINFO - 2] = { "SYSINFO: 0x", hex }, - [AT_SYSINFO_EHDR - 2] = { "SYSINFO_EHDR: 0x", hex }, - [AT_RANDOM - 2] = { "RANDOM: 0x", hex }, - [AT_HWCAP2 - 2] = { "HWCAP2: 0x", hex }, - [AT_MINSIGSTKSZ - 2] = { "MINSIGSTKSZ: ", dec }, - [AT_L1I_CACHESIZE - 2] = { "L1I_CACHESIZE: ", dec }, - [AT_L1I_CACHEGEOMETRY - 2] = { "L1I_CACHEGEOMETRY: 0x", hex }, - [AT_L1D_CACHESIZE - 2] = { "L1D_CACHESIZE: ", dec }, - [AT_L1D_CACHEGEOMETRY - 2] = { "L1D_CACHEGEOMETRY: 0x", hex }, - [AT_L2_CACHESIZE - 2] = { "L2_CACHESIZE: ", dec }, - [AT_L2_CACHEGEOMETRY - 2] = { "L2_CACHEGEOMETRY: 0x", hex }, - [AT_L3_CACHESIZE - 2] = { "L3_CACHESIZE: ", dec }, - [AT_L3_CACHEGEOMETRY - 2] = { "L3_CACHEGEOMETRY: 0x", hex }, - }; - unsigned int idx = (unsigned int) (av->a_type - 2); - - if ((unsigned int) av->a_type < 2u - || (idx < sizeof (auxvars) / sizeof (auxvars[0]) - && auxvars[idx].form == ignore)) - continue; - - assert (AT_NULL == 0); - assert (AT_IGNORE == 1); - - /* Some entries are handled in a special way per platform. */ - if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0) - continue; - - if (idx < sizeof (auxvars) / sizeof (auxvars[0]) - && auxvars[idx].form != unknown) - { - const char *val = (char *) av->a_un.a_val; - - if (__builtin_expect (auxvars[idx].form, dec) == dec) - val = _itoa ((unsigned long int) av->a_un.a_val, - buf + sizeof buf - 1, 10, 0); - else if (__builtin_expect (auxvars[idx].form, hex) == hex) - val = _itoa ((unsigned long int) av->a_un.a_val, - buf + sizeof buf - 1, 16, 0); - - _dl_printf ("AT_%s%s\n", auxvars[idx].label, val); - - continue; - } - - /* Unknown value: print a generic line. */ - char buf2[17]; - buf2[sizeof (buf2) - 1] = '\0'; - const char *val2 = _itoa ((unsigned long int) av->a_un.a_val, - buf2 + sizeof buf2 - 1, 16, 0); - const char *val = _itoa ((unsigned long int) av->a_type, - buf + sizeof buf - 1, 16, 0); - _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2); - } -} - -#endif +#error dl-sysdep support missing. diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index 66ba489cd3..4f60cecf98 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -16,29 +16,352 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -/* Linux needs some special initialization, but otherwise uses - the generic dynamic linker system interface code. */ - -#include <string.h> +#include <_itoa.h> +#include <assert.h> +#include <dl-auxv.h> +#include <dl-hwcap-check.h> +#include <dl-osinfo.h> +#include <dl-procinfo.h> +#include <dl-tunables.h> +#include <elf.h> +#include <entry.h> +#include <errno.h> #include <fcntl.h> -#include <unistd.h> -#include <sys/param.h> -#include <sys/utsname.h> +#include <fpu_control.h> #include <ldsodefs.h> +#include <libc-internal.h> +#include <libintl.h> #include <not-cancel.h> +#include <stdlib.h> +#include <string.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/param.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/utsname.h> +#include <tls.h> +#include <unistd.h> + +#include <dl-machine.h> #ifdef SHARED -# define DL_SYSDEP_INIT frob_brk () +extern char **_environ attribute_hidden; +extern char _end[] attribute_hidden; + +/* Protect SUID program against misuse of file descriptors. */ +extern void __libc_check_standard_fds (void); -static inline void -frob_brk (void) +int __libc_enable_secure attribute_relro = 0; +rtld_hidden_data_def (__libc_enable_secure) +/* This variable contains the lowest stack address ever used. */ +void *__libc_stack_end attribute_relro = NULL; +rtld_hidden_data_def(__libc_stack_end) +void *_dl_random attribute_relro = NULL; + +#ifndef DL_FIND_ARG_COMPONENTS +# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ + do { \ + void **_tmp; \ + (argc) = *(long int *) cookie; \ + (argv) = (char **) ((long int *) cookie + 1); \ + (envp) = (argv) + (argc) + 1; \ + for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ + continue; \ + (auxp) = (void *) ++_tmp; \ + } while (0) +#endif + +#ifndef DL_STACK_END +# define DL_STACK_END(cookie) ((void *) (cookie)) +#endif + +ElfW(Addr) +_dl_sysdep_start (void **start_argptr, + void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, + ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) { + const ElfW(Phdr) *phdr = NULL; + ElfW(Word) phnum = 0; + ElfW(Addr) user_entry; + ElfW(auxv_t) *av; +#ifdef HAVE_AUX_SECURE +# define set_seen(tag) (tag) /* Evaluate for the side effects. */ +# define set_seen_secure() ((void) 0) +#else + uid_t uid = 0; + gid_t gid = 0; + unsigned int seen = 0; +# define set_seen_secure() (seen = -1) +# ifdef HAVE_AUX_XID +# define set_seen(tag) (tag) /* Evaluate for the side effects. */ +# else +# define M(type) (1 << (type)) +# define set_seen(tag) seen |= M ((tag)->a_type) +# endif +#endif +#ifdef NEED_DL_SYSINFO + uintptr_t new_sysinfo = 0; +#endif + + __libc_stack_end = DL_STACK_END (start_argptr); + DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ, + GLRO(dl_auxv)); + + user_entry = (ElfW(Addr)) ENTRY_POINT; + GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ + + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), + "CONSTANT_MINSIGSTKSZ is constant"); + GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; + + for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++)) + switch (av->a_type) + { + case AT_PHDR: + phdr = (void *) av->a_un.a_val; + break; + case AT_PHNUM: + phnum = av->a_un.a_val; + break; + case AT_PAGESZ: + GLRO(dl_pagesize) = av->a_un.a_val; + break; + case AT_ENTRY: + user_entry = av->a_un.a_val; + break; +#ifndef HAVE_AUX_SECURE + case AT_UID: + case AT_EUID: + uid ^= av->a_un.a_val; + break; + case AT_GID: + case AT_EGID: + gid ^= av->a_un.a_val; + break; +#endif + case AT_SECURE: +#ifndef HAVE_AUX_SECURE + seen = -1; +#endif + __libc_enable_secure = av->a_un.a_val; + break; + case AT_PLATFORM: + GLRO(dl_platform) = (void *) av->a_un.a_val; + break; + case AT_HWCAP: + GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; + break; + case AT_HWCAP2: + GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; + break; + case AT_CLKTCK: + GLRO(dl_clktck) = av->a_un.a_val; + break; + case AT_FPUCW: + GLRO(dl_fpu_control) = av->a_un.a_val; + break; +#ifdef NEED_DL_SYSINFO + case AT_SYSINFO: + new_sysinfo = av->a_un.a_val; + break; +#endif +#ifdef NEED_DL_SYSINFO_DSO + case AT_SYSINFO_EHDR: + GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; + break; +#endif + case AT_RANDOM: + _dl_random = (void *) av->a_un.a_val; + break; + case AT_MINSIGSTKSZ: + GLRO(dl_minsigstacksize) = av->a_un.a_val; + break; + DL_PLATFORM_AUXV + } + + dl_hwcap_check (); + +#ifndef HAVE_AUX_SECURE + if (seen != -1) + { + /* Fill in the values we have not gotten from the kernel through the + auxiliary vector. */ +# ifndef HAVE_AUX_XID +# define SEE(UID, var, uid) \ + if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () + SEE (UID, uid, uid); + SEE (EUID, uid, euid); + SEE (GID, gid, gid); + SEE (EGID, gid, egid); +# endif + + /* If one of the two pairs of IDs does not match this is a setuid + or setgid run. */ + __libc_enable_secure = uid | gid; + } +#endif + +#ifndef HAVE_AUX_PAGESIZE + if (GLRO(dl_pagesize) == 0) + GLRO(dl_pagesize) = __getpagesize (); +#endif + +#ifdef NEED_DL_SYSINFO + if (new_sysinfo != 0) + { +# ifdef NEED_DL_SYSINFO_DSO + /* Only set the sysinfo value if we also have the vsyscall DSO. */ + if (GLRO(dl_sysinfo_dso) != 0) +# endif + GLRO(dl_sysinfo) = new_sysinfo; + } +#endif + + __tunables_init (_environ); + + /* Initialize DSO sorting algorithm after tunables. */ + _dl_sort_maps_init (); + __brk (0); /* Initialize the break. */ -} -# include <elf/dl-sysdep.c> +#ifdef DL_PLATFORM_INIT + DL_PLATFORM_INIT; #endif + /* Determine the length of the platform name. */ + if (GLRO(dl_platform) != NULL) + GLRO(dl_platformlen) = strlen (GLRO(dl_platform)); + + if (__sbrk (0) == _end) + /* The dynamic linker was run as a program, and so the initial break + starts just after our bss, at &_end. The malloc in dl-minimal.c + will consume the rest of this page, so tell the kernel to move the + break up that far. When the user program examines its break, it + will see this new value and not clobber our data. */ + __sbrk (GLRO(dl_pagesize) + - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1))); + + /* If this is a SUID program we make sure that FDs 0, 1, and 2 are + allocated. If necessary we are doing it ourself. If it is not + possible we stop the program. */ + if (__builtin_expect (__libc_enable_secure, 0)) + __libc_check_standard_fds (); + + (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv)); + return user_entry; +} + +void +_dl_sysdep_start_cleanup (void) +{ +} + +void +_dl_show_auxv (void) +{ + char buf[64]; + ElfW(auxv_t) *av; + + /* Terminate string. */ + buf[63] = '\0'; + + /* The following code assumes that the AT_* values are encoded + starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values + close by (otherwise the array will be too large). In case we have + to support a platform where these requirements are not fulfilled + some alternative implementation has to be used. */ + for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av) + { + static const struct + { + const char label[22]; + enum { unknown = 0, dec, hex, str, ignore } form : 8; + } auxvars[] = + { + [AT_EXECFD - 2] = { "EXECFD: ", dec }, + [AT_EXECFN - 2] = { "EXECFN: ", str }, + [AT_PHDR - 2] = { "PHDR: 0x", hex }, + [AT_PHENT - 2] = { "PHENT: ", dec }, + [AT_PHNUM - 2] = { "PHNUM: ", dec }, + [AT_PAGESZ - 2] = { "PAGESZ: ", dec }, + [AT_BASE - 2] = { "BASE: 0x", hex }, + [AT_FLAGS - 2] = { "FLAGS: 0x", hex }, + [AT_ENTRY - 2] = { "ENTRY: 0x", hex }, + [AT_NOTELF - 2] = { "NOTELF: ", hex }, + [AT_UID - 2] = { "UID: ", dec }, + [AT_EUID - 2] = { "EUID: ", dec }, + [AT_GID - 2] = { "GID: ", dec }, + [AT_EGID - 2] = { "EGID: ", dec }, + [AT_PLATFORM - 2] = { "PLATFORM: ", str }, + [AT_HWCAP - 2] = { "HWCAP: ", hex }, + [AT_CLKTCK - 2] = { "CLKTCK: ", dec }, + [AT_FPUCW - 2] = { "FPUCW: ", hex }, + [AT_DCACHEBSIZE - 2] = { "DCACHEBSIZE: 0x", hex }, + [AT_ICACHEBSIZE - 2] = { "ICACHEBSIZE: 0x", hex }, + [AT_UCACHEBSIZE - 2] = { "UCACHEBSIZE: 0x", hex }, + [AT_IGNOREPPC - 2] = { "IGNOREPPC", ignore }, + [AT_SECURE - 2] = { "SECURE: ", dec }, + [AT_BASE_PLATFORM - 2] = { "BASE_PLATFORM: ", str }, + [AT_SYSINFO - 2] = { "SYSINFO: 0x", hex }, + [AT_SYSINFO_EHDR - 2] = { "SYSINFO_EHDR: 0x", hex }, + [AT_RANDOM - 2] = { "RANDOM: 0x", hex }, + [AT_HWCAP2 - 2] = { "HWCAP2: 0x", hex }, + [AT_MINSIGSTKSZ - 2] = { "MINSIGSTKSZ: ", dec }, + [AT_L1I_CACHESIZE - 2] = { "L1I_CACHESIZE: ", dec }, + [AT_L1I_CACHEGEOMETRY - 2] = { "L1I_CACHEGEOMETRY: 0x", hex }, + [AT_L1D_CACHESIZE - 2] = { "L1D_CACHESIZE: ", dec }, + [AT_L1D_CACHEGEOMETRY - 2] = { "L1D_CACHEGEOMETRY: 0x", hex }, + [AT_L2_CACHESIZE - 2] = { "L2_CACHESIZE: ", dec }, + [AT_L2_CACHEGEOMETRY - 2] = { "L2_CACHEGEOMETRY: 0x", hex }, + [AT_L3_CACHESIZE - 2] = { "L3_CACHESIZE: ", dec }, + [AT_L3_CACHEGEOMETRY - 2] = { "L3_CACHEGEOMETRY: 0x", hex }, + }; + unsigned int idx = (unsigned int) (av->a_type - 2); + + if ((unsigned int) av->a_type < 2u + || (idx < sizeof (auxvars) / sizeof (auxvars[0]) + && auxvars[idx].form == ignore)) + continue; + + assert (AT_NULL == 0); + assert (AT_IGNORE == 1); + + /* Some entries are handled in a special way per platform. */ + if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0) + continue; + + if (idx < sizeof (auxvars) / sizeof (auxvars[0]) + && auxvars[idx].form != unknown) + { + const char *val = (char *) av->a_un.a_val; + + if (__builtin_expect (auxvars[idx].form, dec) == dec) + val = _itoa ((unsigned long int) av->a_un.a_val, + buf + sizeof buf - 1, 10, 0); + else if (__builtin_expect (auxvars[idx].form, hex) == hex) + val = _itoa ((unsigned long int) av->a_un.a_val, + buf + sizeof buf - 1, 16, 0); + + _dl_printf ("AT_%s%s\n", auxvars[idx].label, val); + + continue; + } + + /* Unknown value: print a generic line. */ + char buf2[17]; + buf2[sizeof (buf2) - 1] = '\0'; + const char *val2 = _itoa ((unsigned long int) av->a_un.a_val, + buf2 + sizeof buf2 - 1, 16, 0); + const char *val = _itoa ((unsigned long int) av->a_type, + buf + sizeof buf - 1, 16, 0); + _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2); + } +} + +#endif /* SHARED */ + int attribute_hidden -- 2.34.1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version 2022-02-03 11:08 ` [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version Florian Weimer @ 2022-02-08 20:09 ` Adhemerval Zanella 0 siblings, 0 replies; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-08 20:09 UTC (permalink / raw) To: Florian Weimer, libc-alpha On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote: > The generic version is the de-facto Linux implementation. It > requires an auxiliary vector, so Hurd does not use it. LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > elf/dl-sysdep.c | 352 +--------------------------- > sysdeps/unix/sysv/linux/dl-sysdep.c | 347 ++++++++++++++++++++++++++- > 2 files changed, 337 insertions(+), 362 deletions(-) > > diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c > index f1dba8ef24..7aa90ad6ee 100644 > --- a/elf/dl-sysdep.c > +++ b/elf/dl-sysdep.c > @@ -1,4 +1,4 @@ > -/* Operating system support for run-time dynamic linker. Generic Unix version. > +/* Operating system support for run-time dynamic linker. Stub version. > Copyright (C) 1995-2022 Free Software Foundation, Inc. > This file is part of the GNU C Library. > > @@ -16,352 +16,4 @@ > License along with the GNU C Library; if not, see > <https://www.gnu.org/licenses/>. */ > > -/* We conditionalize the whole of this file rather than simply eliding it > - from the static build, because other sysdeps/ versions of this file > - might define things needed by a static build. */ > - > -#ifdef SHARED > - > -#include <assert.h> > -#include <elf.h> > -#include <errno.h> > -#include <fcntl.h> > -#include <libintl.h> > -#include <stdlib.h> > -#include <string.h> > -#include <unistd.h> > -#include <sys/types.h> > -#include <sys/stat.h> > -#include <sys/mman.h> > -#include <ldsodefs.h> > -#include <_itoa.h> > -#include <fpu_control.h> > - > -#include <entry.h> > -#include <dl-machine.h> > -#include <dl-procinfo.h> > -#include <dl-osinfo.h> > -#include <libc-internal.h> > -#include <tls.h> > - > -#include <dl-tunables.h> > -#include <dl-auxv.h> > -#include <dl-hwcap-check.h> > - > -extern char **_environ attribute_hidden; > -extern char _end[] attribute_hidden; > - > -/* Protect SUID program against misuse of file descriptors. */ > -extern void __libc_check_standard_fds (void); > - > -int __libc_enable_secure attribute_relro = 0; > -rtld_hidden_data_def (__libc_enable_secure) > -/* This variable contains the lowest stack address ever used. */ > -void *__libc_stack_end attribute_relro = NULL; > -rtld_hidden_data_def(__libc_stack_end) > -void *_dl_random attribute_relro = NULL; > - > -#ifndef DL_FIND_ARG_COMPONENTS > -# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ > - do { \ > - void **_tmp; \ > - (argc) = *(long int *) cookie; \ > - (argv) = (char **) ((long int *) cookie + 1); \ > - (envp) = (argv) + (argc) + 1; \ > - for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ > - continue; \ > - (auxp) = (void *) ++_tmp; \ > - } while (0) > -#endif > - > -#ifndef DL_STACK_END > -# define DL_STACK_END(cookie) ((void *) (cookie)) > -#endif > - > -ElfW(Addr) > -_dl_sysdep_start (void **start_argptr, > - void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, > - ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) > -{ > - const ElfW(Phdr) *phdr = NULL; > - ElfW(Word) phnum = 0; > - ElfW(Addr) user_entry; > - ElfW(auxv_t) *av; > -#ifdef HAVE_AUX_SECURE > -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ > -# define set_seen_secure() ((void) 0) > -#else > - uid_t uid = 0; > - gid_t gid = 0; > - unsigned int seen = 0; > -# define set_seen_secure() (seen = -1) > -# ifdef HAVE_AUX_XID > -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ > -# else > -# define M(type) (1 << (type)) > -# define set_seen(tag) seen |= M ((tag)->a_type) > -# endif > -#endif > -#ifdef NEED_DL_SYSINFO > - uintptr_t new_sysinfo = 0; > -#endif > - > - __libc_stack_end = DL_STACK_END (start_argptr); > - DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ, > - GLRO(dl_auxv)); > - > - user_entry = (ElfW(Addr)) ENTRY_POINT; > - GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ > - > - /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ > - _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), > - "CONSTANT_MINSIGSTKSZ is constant"); > - GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; > - > - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++)) > - switch (av->a_type) > - { > - case AT_PHDR: > - phdr = (void *) av->a_un.a_val; > - break; > - case AT_PHNUM: > - phnum = av->a_un.a_val; > - break; > - case AT_PAGESZ: > - GLRO(dl_pagesize) = av->a_un.a_val; > - break; > - case AT_ENTRY: > - user_entry = av->a_un.a_val; > - break; > -#ifndef HAVE_AUX_SECURE > - case AT_UID: > - case AT_EUID: > - uid ^= av->a_un.a_val; > - break; > - case AT_GID: > - case AT_EGID: > - gid ^= av->a_un.a_val; > - break; > -#endif > - case AT_SECURE: > -#ifndef HAVE_AUX_SECURE > - seen = -1; > -#endif > - __libc_enable_secure = av->a_un.a_val; > - break; > - case AT_PLATFORM: > - GLRO(dl_platform) = (void *) av->a_un.a_val; > - break; > - case AT_HWCAP: > - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_HWCAP2: > - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_CLKTCK: > - GLRO(dl_clktck) = av->a_un.a_val; > - break; > - case AT_FPUCW: > - GLRO(dl_fpu_control) = av->a_un.a_val; > - break; > -#ifdef NEED_DL_SYSINFO > - case AT_SYSINFO: > - new_sysinfo = av->a_un.a_val; > - break; > -#endif > -#ifdef NEED_DL_SYSINFO_DSO > - case AT_SYSINFO_EHDR: > - GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; > - break; > -#endif > - case AT_RANDOM: > - _dl_random = (void *) av->a_un.a_val; > - break; > - case AT_MINSIGSTKSZ: > - GLRO(dl_minsigstacksize) = av->a_un.a_val; > - break; > - DL_PLATFORM_AUXV > - } > - > - dl_hwcap_check (); > - > -#ifndef HAVE_AUX_SECURE > - if (seen != -1) > - { > - /* Fill in the values we have not gotten from the kernel through the > - auxiliary vector. */ > -# ifndef HAVE_AUX_XID > -# define SEE(UID, var, uid) \ > - if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () > - SEE (UID, uid, uid); > - SEE (EUID, uid, euid); > - SEE (GID, gid, gid); > - SEE (EGID, gid, egid); > -# endif > - > - /* If one of the two pairs of IDs does not match this is a setuid > - or setgid run. */ > - __libc_enable_secure = uid | gid; > - } > -#endif > - > -#ifndef HAVE_AUX_PAGESIZE > - if (GLRO(dl_pagesize) == 0) > - GLRO(dl_pagesize) = __getpagesize (); > -#endif > - > -#ifdef NEED_DL_SYSINFO > - if (new_sysinfo != 0) > - { > -# ifdef NEED_DL_SYSINFO_DSO > - /* Only set the sysinfo value if we also have the vsyscall DSO. */ > - if (GLRO(dl_sysinfo_dso) != 0) > -# endif > - GLRO(dl_sysinfo) = new_sysinfo; > - } > -#endif > - > - __tunables_init (_environ); > - > - /* Initialize DSO sorting algorithm after tunables. */ > - _dl_sort_maps_init (); > - > -#ifdef DL_SYSDEP_INIT > - DL_SYSDEP_INIT; > -#endif > - > -#ifdef DL_PLATFORM_INIT > - DL_PLATFORM_INIT; > -#endif > - > - /* Determine the length of the platform name. */ > - if (GLRO(dl_platform) != NULL) > - GLRO(dl_platformlen) = strlen (GLRO(dl_platform)); > - > - if (__sbrk (0) == _end) > - /* The dynamic linker was run as a program, and so the initial break > - starts just after our bss, at &_end. The malloc in dl-minimal.c > - will consume the rest of this page, so tell the kernel to move the > - break up that far. When the user program examines its break, it > - will see this new value and not clobber our data. */ > - __sbrk (GLRO(dl_pagesize) > - - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1))); > - > - /* If this is a SUID program we make sure that FDs 0, 1, and 2 are > - allocated. If necessary we are doing it ourself. If it is not > - possible we stop the program. */ > - if (__builtin_expect (__libc_enable_secure, 0)) > - __libc_check_standard_fds (); > - > - (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv)); > - return user_entry; > -} > - > -void > -_dl_sysdep_start_cleanup (void) > -{ > -} > - > -void > -_dl_show_auxv (void) > -{ > - char buf[64]; > - ElfW(auxv_t) *av; > - > - /* Terminate string. */ > - buf[63] = '\0'; > - > - /* The following code assumes that the AT_* values are encoded > - starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values > - close by (otherwise the array will be too large). In case we have > - to support a platform where these requirements are not fulfilled > - some alternative implementation has to be used. */ > - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av) > - { > - static const struct > - { > - const char label[22]; > - enum { unknown = 0, dec, hex, str, ignore } form : 8; > - } auxvars[] = > - { > - [AT_EXECFD - 2] = { "EXECFD: ", dec }, > - [AT_EXECFN - 2] = { "EXECFN: ", str }, > - [AT_PHDR - 2] = { "PHDR: 0x", hex }, > - [AT_PHENT - 2] = { "PHENT: ", dec }, > - [AT_PHNUM - 2] = { "PHNUM: ", dec }, > - [AT_PAGESZ - 2] = { "PAGESZ: ", dec }, > - [AT_BASE - 2] = { "BASE: 0x", hex }, > - [AT_FLAGS - 2] = { "FLAGS: 0x", hex }, > - [AT_ENTRY - 2] = { "ENTRY: 0x", hex }, > - [AT_NOTELF - 2] = { "NOTELF: ", hex }, > - [AT_UID - 2] = { "UID: ", dec }, > - [AT_EUID - 2] = { "EUID: ", dec }, > - [AT_GID - 2] = { "GID: ", dec }, > - [AT_EGID - 2] = { "EGID: ", dec }, > - [AT_PLATFORM - 2] = { "PLATFORM: ", str }, > - [AT_HWCAP - 2] = { "HWCAP: ", hex }, > - [AT_CLKTCK - 2] = { "CLKTCK: ", dec }, > - [AT_FPUCW - 2] = { "FPUCW: ", hex }, > - [AT_DCACHEBSIZE - 2] = { "DCACHEBSIZE: 0x", hex }, > - [AT_ICACHEBSIZE - 2] = { "ICACHEBSIZE: 0x", hex }, > - [AT_UCACHEBSIZE - 2] = { "UCACHEBSIZE: 0x", hex }, > - [AT_IGNOREPPC - 2] = { "IGNOREPPC", ignore }, > - [AT_SECURE - 2] = { "SECURE: ", dec }, > - [AT_BASE_PLATFORM - 2] = { "BASE_PLATFORM: ", str }, > - [AT_SYSINFO - 2] = { "SYSINFO: 0x", hex }, > - [AT_SYSINFO_EHDR - 2] = { "SYSINFO_EHDR: 0x", hex }, > - [AT_RANDOM - 2] = { "RANDOM: 0x", hex }, > - [AT_HWCAP2 - 2] = { "HWCAP2: 0x", hex }, > - [AT_MINSIGSTKSZ - 2] = { "MINSIGSTKSZ: ", dec }, > - [AT_L1I_CACHESIZE - 2] = { "L1I_CACHESIZE: ", dec }, > - [AT_L1I_CACHEGEOMETRY - 2] = { "L1I_CACHEGEOMETRY: 0x", hex }, > - [AT_L1D_CACHESIZE - 2] = { "L1D_CACHESIZE: ", dec }, > - [AT_L1D_CACHEGEOMETRY - 2] = { "L1D_CACHEGEOMETRY: 0x", hex }, > - [AT_L2_CACHESIZE - 2] = { "L2_CACHESIZE: ", dec }, > - [AT_L2_CACHEGEOMETRY - 2] = { "L2_CACHEGEOMETRY: 0x", hex }, > - [AT_L3_CACHESIZE - 2] = { "L3_CACHESIZE: ", dec }, > - [AT_L3_CACHEGEOMETRY - 2] = { "L3_CACHEGEOMETRY: 0x", hex }, > - }; > - unsigned int idx = (unsigned int) (av->a_type - 2); > - > - if ((unsigned int) av->a_type < 2u > - || (idx < sizeof (auxvars) / sizeof (auxvars[0]) > - && auxvars[idx].form == ignore)) > - continue; > - > - assert (AT_NULL == 0); > - assert (AT_IGNORE == 1); > - > - /* Some entries are handled in a special way per platform. */ > - if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0) > - continue; > - > - if (idx < sizeof (auxvars) / sizeof (auxvars[0]) > - && auxvars[idx].form != unknown) > - { > - const char *val = (char *) av->a_un.a_val; > - > - if (__builtin_expect (auxvars[idx].form, dec) == dec) > - val = _itoa ((unsigned long int) av->a_un.a_val, > - buf + sizeof buf - 1, 10, 0); > - else if (__builtin_expect (auxvars[idx].form, hex) == hex) > - val = _itoa ((unsigned long int) av->a_un.a_val, > - buf + sizeof buf - 1, 16, 0); > - > - _dl_printf ("AT_%s%s\n", auxvars[idx].label, val); > - > - continue; > - } > - > - /* Unknown value: print a generic line. */ > - char buf2[17]; > - buf2[sizeof (buf2) - 1] = '\0'; > - const char *val2 = _itoa ((unsigned long int) av->a_un.a_val, > - buf2 + sizeof buf2 - 1, 16, 0); > - const char *val = _itoa ((unsigned long int) av->a_type, > - buf + sizeof buf - 1, 16, 0); > - _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2); > - } > -} > - > -#endif > +#error dl-sysdep support missing. > diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c > index 66ba489cd3..4f60cecf98 100644 > --- a/sysdeps/unix/sysv/linux/dl-sysdep.c > +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c > @@ -16,29 +16,352 @@ > License along with the GNU C Library; if not, see > <https://www.gnu.org/licenses/>. */ > > -/* Linux needs some special initialization, but otherwise uses > - the generic dynamic linker system interface code. */ > - > -#include <string.h> > +#include <_itoa.h> > +#include <assert.h> > +#include <dl-auxv.h> > +#include <dl-hwcap-check.h> > +#include <dl-osinfo.h> > +#include <dl-procinfo.h> > +#include <dl-tunables.h> > +#include <elf.h> > +#include <entry.h> > +#include <errno.h> > #include <fcntl.h> > -#include <unistd.h> > -#include <sys/param.h> > -#include <sys/utsname.h> > +#include <fpu_control.h> > #include <ldsodefs.h> > +#include <libc-internal.h> > +#include <libintl.h> > #include <not-cancel.h> > +#include <stdlib.h> > +#include <string.h> > +#include <string.h> > +#include <sys/mman.h> > +#include <sys/param.h> > +#include <sys/stat.h> > +#include <sys/types.h> > +#include <sys/utsname.h> > +#include <tls.h> > +#include <unistd.h> > + > +#include <dl-machine.h> > > #ifdef SHARED > -# define DL_SYSDEP_INIT frob_brk () > +extern char **_environ attribute_hidden; > +extern char _end[] attribute_hidden; > + > +/* Protect SUID program against misuse of file descriptors. */ > +extern void __libc_check_standard_fds (void); > > -static inline void > -frob_brk (void) > +int __libc_enable_secure attribute_relro = 0; > +rtld_hidden_data_def (__libc_enable_secure) > +/* This variable contains the lowest stack address ever used. */ > +void *__libc_stack_end attribute_relro = NULL; > +rtld_hidden_data_def(__libc_stack_end) > +void *_dl_random attribute_relro = NULL; > + > +#ifndef DL_FIND_ARG_COMPONENTS > +# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ > + do { \ > + void **_tmp; \ > + (argc) = *(long int *) cookie; \ > + (argv) = (char **) ((long int *) cookie + 1); \ > + (envp) = (argv) + (argc) + 1; \ > + for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ > + continue; \ > + (auxp) = (void *) ++_tmp; \ > + } while (0) > +#endif > + > +#ifndef DL_STACK_END > +# define DL_STACK_END(cookie) ((void *) (cookie)) > +#endif > + > +ElfW(Addr) > +_dl_sysdep_start (void **start_argptr, > + void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, > + ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) > { > + const ElfW(Phdr) *phdr = NULL; > + ElfW(Word) phnum = 0; > + ElfW(Addr) user_entry; > + ElfW(auxv_t) *av; > +#ifdef HAVE_AUX_SECURE > +# define set_seen(tag) (tag) /* Evaluate for the side effects. */ > +# define set_seen_secure() ((void) 0) > +#else > + uid_t uid = 0; > + gid_t gid = 0; > + unsigned int seen = 0; > +# define set_seen_secure() (seen = -1) > +# ifdef HAVE_AUX_XID > +# define set_seen(tag) (tag) /* Evaluate for the side effects. */ > +# else > +# define M(type) (1 << (type)) > +# define set_seen(tag) seen |= M ((tag)->a_type) > +# endif > +#endif > +#ifdef NEED_DL_SYSINFO > + uintptr_t new_sysinfo = 0; > +#endif > + > + __libc_stack_end = DL_STACK_END (start_argptr); > + DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ, > + GLRO(dl_auxv)); > + > + user_entry = (ElfW(Addr)) ENTRY_POINT; > + GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ > + > + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ > + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), > + "CONSTANT_MINSIGSTKSZ is constant"); > + GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; > + > + for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++)) > + switch (av->a_type) > + { > + case AT_PHDR: > + phdr = (void *) av->a_un.a_val; > + break; > + case AT_PHNUM: > + phnum = av->a_un.a_val; > + break; > + case AT_PAGESZ: > + GLRO(dl_pagesize) = av->a_un.a_val; > + break; > + case AT_ENTRY: > + user_entry = av->a_un.a_val; > + break; > +#ifndef HAVE_AUX_SECURE > + case AT_UID: > + case AT_EUID: > + uid ^= av->a_un.a_val; > + break; > + case AT_GID: > + case AT_EGID: > + gid ^= av->a_un.a_val; > + break; > +#endif > + case AT_SECURE: > +#ifndef HAVE_AUX_SECURE > + seen = -1; > +#endif > + __libc_enable_secure = av->a_un.a_val; > + break; > + case AT_PLATFORM: > + GLRO(dl_platform) = (void *) av->a_un.a_val; > + break; > + case AT_HWCAP: > + GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; > + break; > + case AT_HWCAP2: > + GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; > + break; > + case AT_CLKTCK: > + GLRO(dl_clktck) = av->a_un.a_val; > + break; > + case AT_FPUCW: > + GLRO(dl_fpu_control) = av->a_un.a_val; > + break; > +#ifdef NEED_DL_SYSINFO > + case AT_SYSINFO: > + new_sysinfo = av->a_un.a_val; > + break; > +#endif > +#ifdef NEED_DL_SYSINFO_DSO > + case AT_SYSINFO_EHDR: > + GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; > + break; > +#endif > + case AT_RANDOM: > + _dl_random = (void *) av->a_un.a_val; > + break; > + case AT_MINSIGSTKSZ: > + GLRO(dl_minsigstacksize) = av->a_un.a_val; > + break; > + DL_PLATFORM_AUXV > + } > + > + dl_hwcap_check (); > + > +#ifndef HAVE_AUX_SECURE > + if (seen != -1) > + { > + /* Fill in the values we have not gotten from the kernel through the > + auxiliary vector. */ > +# ifndef HAVE_AUX_XID > +# define SEE(UID, var, uid) \ > + if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () > + SEE (UID, uid, uid); > + SEE (EUID, uid, euid); > + SEE (GID, gid, gid); > + SEE (EGID, gid, egid); > +# endif > + > + /* If one of the two pairs of IDs does not match this is a setuid > + or setgid run. */ > + __libc_enable_secure = uid | gid; > + } > +#endif > + > +#ifndef HAVE_AUX_PAGESIZE > + if (GLRO(dl_pagesize) == 0) > + GLRO(dl_pagesize) = __getpagesize (); > +#endif > + > +#ifdef NEED_DL_SYSINFO > + if (new_sysinfo != 0) > + { > +# ifdef NEED_DL_SYSINFO_DSO > + /* Only set the sysinfo value if we also have the vsyscall DSO. */ > + if (GLRO(dl_sysinfo_dso) != 0) > +# endif > + GLRO(dl_sysinfo) = new_sysinfo; > + } > +#endif > + > + __tunables_init (_environ); > + > + /* Initialize DSO sorting algorithm after tunables. */ > + _dl_sort_maps_init (); > + > __brk (0); /* Initialize the break. */ > -} > > -# include <elf/dl-sysdep.c> > +#ifdef DL_PLATFORM_INIT > + DL_PLATFORM_INIT; > #endif > > + /* Determine the length of the platform name. */ > + if (GLRO(dl_platform) != NULL) > + GLRO(dl_platformlen) = strlen (GLRO(dl_platform)); > + > + if (__sbrk (0) == _end) > + /* The dynamic linker was run as a program, and so the initial break > + starts just after our bss, at &_end. The malloc in dl-minimal.c > + will consume the rest of this page, so tell the kernel to move the > + break up that far. When the user program examines its break, it > + will see this new value and not clobber our data. */ > + __sbrk (GLRO(dl_pagesize) > + - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1))); > + > + /* If this is a SUID program we make sure that FDs 0, 1, and 2 are > + allocated. If necessary we are doing it ourself. If it is not > + possible we stop the program. */ > + if (__builtin_expect (__libc_enable_secure, 0)) > + __libc_check_standard_fds (); > + > + (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv)); > + return user_entry; > +} > + > +void > +_dl_sysdep_start_cleanup (void) > +{ > +} > + > +void > +_dl_show_auxv (void) > +{ > + char buf[64]; > + ElfW(auxv_t) *av; > + > + /* Terminate string. */ > + buf[63] = '\0'; > + > + /* The following code assumes that the AT_* values are encoded > + starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values > + close by (otherwise the array will be too large). In case we have > + to support a platform where these requirements are not fulfilled > + some alternative implementation has to be used. */ > + for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av) > + { > + static const struct > + { > + const char label[22]; > + enum { unknown = 0, dec, hex, str, ignore } form : 8; > + } auxvars[] = > + { > + [AT_EXECFD - 2] = { "EXECFD: ", dec }, > + [AT_EXECFN - 2] = { "EXECFN: ", str }, > + [AT_PHDR - 2] = { "PHDR: 0x", hex }, > + [AT_PHENT - 2] = { "PHENT: ", dec }, > + [AT_PHNUM - 2] = { "PHNUM: ", dec }, > + [AT_PAGESZ - 2] = { "PAGESZ: ", dec }, > + [AT_BASE - 2] = { "BASE: 0x", hex }, > + [AT_FLAGS - 2] = { "FLAGS: 0x", hex }, > + [AT_ENTRY - 2] = { "ENTRY: 0x", hex }, > + [AT_NOTELF - 2] = { "NOTELF: ", hex }, > + [AT_UID - 2] = { "UID: ", dec }, > + [AT_EUID - 2] = { "EUID: ", dec }, > + [AT_GID - 2] = { "GID: ", dec }, > + [AT_EGID - 2] = { "EGID: ", dec }, > + [AT_PLATFORM - 2] = { "PLATFORM: ", str }, > + [AT_HWCAP - 2] = { "HWCAP: ", hex }, > + [AT_CLKTCK - 2] = { "CLKTCK: ", dec }, > + [AT_FPUCW - 2] = { "FPUCW: ", hex }, > + [AT_DCACHEBSIZE - 2] = { "DCACHEBSIZE: 0x", hex }, > + [AT_ICACHEBSIZE - 2] = { "ICACHEBSIZE: 0x", hex }, > + [AT_UCACHEBSIZE - 2] = { "UCACHEBSIZE: 0x", hex }, > + [AT_IGNOREPPC - 2] = { "IGNOREPPC", ignore }, > + [AT_SECURE - 2] = { "SECURE: ", dec }, > + [AT_BASE_PLATFORM - 2] = { "BASE_PLATFORM: ", str }, > + [AT_SYSINFO - 2] = { "SYSINFO: 0x", hex }, > + [AT_SYSINFO_EHDR - 2] = { "SYSINFO_EHDR: 0x", hex }, > + [AT_RANDOM - 2] = { "RANDOM: 0x", hex }, > + [AT_HWCAP2 - 2] = { "HWCAP2: 0x", hex }, > + [AT_MINSIGSTKSZ - 2] = { "MINSIGSTKSZ: ", dec }, > + [AT_L1I_CACHESIZE - 2] = { "L1I_CACHESIZE: ", dec }, > + [AT_L1I_CACHEGEOMETRY - 2] = { "L1I_CACHEGEOMETRY: 0x", hex }, > + [AT_L1D_CACHESIZE - 2] = { "L1D_CACHESIZE: ", dec }, > + [AT_L1D_CACHEGEOMETRY - 2] = { "L1D_CACHEGEOMETRY: 0x", hex }, > + [AT_L2_CACHESIZE - 2] = { "L2_CACHESIZE: ", dec }, > + [AT_L2_CACHEGEOMETRY - 2] = { "L2_CACHEGEOMETRY: 0x", hex }, > + [AT_L3_CACHESIZE - 2] = { "L3_CACHESIZE: ", dec }, > + [AT_L3_CACHEGEOMETRY - 2] = { "L3_CACHEGEOMETRY: 0x", hex }, > + }; > + unsigned int idx = (unsigned int) (av->a_type - 2); > + > + if ((unsigned int) av->a_type < 2u > + || (idx < sizeof (auxvars) / sizeof (auxvars[0]) > + && auxvars[idx].form == ignore)) > + continue; > + > + assert (AT_NULL == 0); > + assert (AT_IGNORE == 1); > + > + /* Some entries are handled in a special way per platform. */ > + if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0) > + continue; > + > + if (idx < sizeof (auxvars) / sizeof (auxvars[0]) > + && auxvars[idx].form != unknown) > + { > + const char *val = (char *) av->a_un.a_val; > + > + if (__builtin_expect (auxvars[idx].form, dec) == dec) > + val = _itoa ((unsigned long int) av->a_un.a_val, > + buf + sizeof buf - 1, 10, 0); > + else if (__builtin_expect (auxvars[idx].form, hex) == hex) > + val = _itoa ((unsigned long int) av->a_un.a_val, > + buf + sizeof buf - 1, 16, 0); > + > + _dl_printf ("AT_%s%s\n", auxvars[idx].label, val); > + > + continue; > + } > + > + /* Unknown value: print a generic line. */ > + char buf2[17]; > + buf2[sizeof (buf2) - 1] = '\0'; > + const char *val2 = _itoa ((unsigned long int) av->a_un.a_val, > + buf2 + sizeof buf2 - 1, 16, 0); > + const char *val = _itoa ((unsigned long int) av->a_type, > + buf + sizeof buf - 1, 16, 0); > + _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2); > + } > +} > + > +#endif /* SHARED */ > + > > int > attribute_hidden ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE 2022-02-03 11:08 [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups Florian Weimer 2022-02-03 11:08 ` [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version Florian Weimer @ 2022-02-03 11:08 ` Florian Weimer 2022-02-08 20:11 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 3/5] Linux: Remove DL_FIND_ARG_COMPONENTS Florian Weimer ` (2 subsequent siblings) 4 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-03 11:08 UTC (permalink / raw) To: libc-alpha They are always defined. --- sysdeps/unix/sysv/linux/dl-sysdep.c | 55 +---------------------------- sysdeps/unix/sysv/linux/ldsodefs.h | 12 ------- 2 files changed, 1 insertion(+), 66 deletions(-) diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index 4f60cecf98..72aa109f2f 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -85,21 +85,6 @@ _dl_sysdep_start (void **start_argptr, ElfW(Word) phnum = 0; ElfW(Addr) user_entry; ElfW(auxv_t) *av; -#ifdef HAVE_AUX_SECURE -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ -# define set_seen_secure() ((void) 0) -#else - uid_t uid = 0; - gid_t gid = 0; - unsigned int seen = 0; -# define set_seen_secure() (seen = -1) -# ifdef HAVE_AUX_XID -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ -# else -# define M(type) (1 << (type)) -# define set_seen(tag) seen |= M ((tag)->a_type) -# endif -#endif #ifdef NEED_DL_SYSINFO uintptr_t new_sysinfo = 0; #endif @@ -116,7 +101,7 @@ _dl_sysdep_start (void **start_argptr, "CONSTANT_MINSIGSTKSZ is constant"); GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++)) + for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++) switch (av->a_type) { case AT_PHDR: @@ -131,20 +116,7 @@ _dl_sysdep_start (void **start_argptr, case AT_ENTRY: user_entry = av->a_un.a_val; break; -#ifndef HAVE_AUX_SECURE - case AT_UID: - case AT_EUID: - uid ^= av->a_un.a_val; - break; - case AT_GID: - case AT_EGID: - gid ^= av->a_un.a_val; - break; -#endif case AT_SECURE: -#ifndef HAVE_AUX_SECURE - seen = -1; -#endif __libc_enable_secure = av->a_un.a_val; break; case AT_PLATFORM: @@ -183,31 +155,6 @@ _dl_sysdep_start (void **start_argptr, dl_hwcap_check (); -#ifndef HAVE_AUX_SECURE - if (seen != -1) - { - /* Fill in the values we have not gotten from the kernel through the - auxiliary vector. */ -# ifndef HAVE_AUX_XID -# define SEE(UID, var, uid) \ - if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () - SEE (UID, uid, uid); - SEE (EUID, uid, euid); - SEE (GID, gid, gid); - SEE (EGID, gid, egid); -# endif - - /* If one of the two pairs of IDs does not match this is a setuid - or setgid run. */ - __libc_enable_secure = uid | gid; - } -#endif - -#ifndef HAVE_AUX_PAGESIZE - if (GLRO(dl_pagesize) == 0) - GLRO(dl_pagesize) = __getpagesize (); -#endif - #ifdef NEED_DL_SYSINFO if (new_sysinfo != 0) { diff --git a/sysdeps/unix/sysv/linux/ldsodefs.h b/sysdeps/unix/sysv/linux/ldsodefs.h index 011756ddc1..af108991f0 100644 --- a/sysdeps/unix/sysv/linux/ldsodefs.h +++ b/sysdeps/unix/sysv/linux/ldsodefs.h @@ -24,16 +24,4 @@ /* Get the real definitions. */ #include_next <ldsodefs.h> -/* We can assume that the kernel always provides the AT_UID, AT_EUID, - AT_GID, and AT_EGID values in the auxiliary vector from 2.4.0 or so on. */ -#define HAVE_AUX_XID - -/* We can assume that the kernel always provides the AT_SECURE value - in the auxiliary vector from 2.5.74 or so on. */ -#define HAVE_AUX_SECURE - -/* Starting with one of the 2.4.0 pre-releases the Linux kernel passes - up the page size information. */ -#define HAVE_AUX_PAGESIZE - #endif /* ldsodefs.h */ -- 2.34.1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE 2022-02-03 11:08 ` [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE Florian Weimer @ 2022-02-08 20:11 ` Adhemerval Zanella 0 siblings, 0 replies; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-08 20:11 UTC (permalink / raw) To: Florian Weimer, libc-alpha On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote: > They are always defined. LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > sysdeps/unix/sysv/linux/dl-sysdep.c | 55 +---------------------------- > sysdeps/unix/sysv/linux/ldsodefs.h | 12 ------- > 2 files changed, 1 insertion(+), 66 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c > index 4f60cecf98..72aa109f2f 100644 > --- a/sysdeps/unix/sysv/linux/dl-sysdep.c > +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c > @@ -85,21 +85,6 @@ _dl_sysdep_start (void **start_argptr, > ElfW(Word) phnum = 0; > ElfW(Addr) user_entry; > ElfW(auxv_t) *av; > -#ifdef HAVE_AUX_SECURE > -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ > -# define set_seen_secure() ((void) 0) > -#else > - uid_t uid = 0; > - gid_t gid = 0; > - unsigned int seen = 0; > -# define set_seen_secure() (seen = -1) > -# ifdef HAVE_AUX_XID > -# define set_seen(tag) (tag) /* Evaluate for the side effects. */ > -# else > -# define M(type) (1 << (type)) > -# define set_seen(tag) seen |= M ((tag)->a_type) > -# endif > -#endif > #ifdef NEED_DL_SYSINFO > uintptr_t new_sysinfo = 0; > #endif > @@ -116,7 +101,7 @@ _dl_sysdep_start (void **start_argptr, > "CONSTANT_MINSIGSTKSZ is constant"); > GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; > > - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++)) > + for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++) > switch (av->a_type) > { > case AT_PHDR: > @@ -131,20 +116,7 @@ _dl_sysdep_start (void **start_argptr, > case AT_ENTRY: > user_entry = av->a_un.a_val; > break; > -#ifndef HAVE_AUX_SECURE > - case AT_UID: > - case AT_EUID: > - uid ^= av->a_un.a_val; > - break; > - case AT_GID: > - case AT_EGID: > - gid ^= av->a_un.a_val; > - break; > -#endif > case AT_SECURE: > -#ifndef HAVE_AUX_SECURE > - seen = -1; > -#endif > __libc_enable_secure = av->a_un.a_val; > break; > case AT_PLATFORM: > @@ -183,31 +155,6 @@ _dl_sysdep_start (void **start_argptr, > > dl_hwcap_check (); > > -#ifndef HAVE_AUX_SECURE > - if (seen != -1) > - { > - /* Fill in the values we have not gotten from the kernel through the > - auxiliary vector. */ > -# ifndef HAVE_AUX_XID > -# define SEE(UID, var, uid) \ > - if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () > - SEE (UID, uid, uid); > - SEE (EUID, uid, euid); > - SEE (GID, gid, gid); > - SEE (EGID, gid, egid); > -# endif > - > - /* If one of the two pairs of IDs does not match this is a setuid > - or setgid run. */ > - __libc_enable_secure = uid | gid; > - } > -#endif > - > -#ifndef HAVE_AUX_PAGESIZE > - if (GLRO(dl_pagesize) == 0) > - GLRO(dl_pagesize) = __getpagesize (); > -#endif > - > #ifdef NEED_DL_SYSINFO > if (new_sysinfo != 0) > { > diff --git a/sysdeps/unix/sysv/linux/ldsodefs.h b/sysdeps/unix/sysv/linux/ldsodefs.h > index 011756ddc1..af108991f0 100644 > --- a/sysdeps/unix/sysv/linux/ldsodefs.h > +++ b/sysdeps/unix/sysv/linux/ldsodefs.h > @@ -24,16 +24,4 @@ > /* Get the real definitions. */ > #include_next <ldsodefs.h> > > -/* We can assume that the kernel always provides the AT_UID, AT_EUID, > - AT_GID, and AT_EGID values in the auxiliary vector from 2.4.0 or so on. */ > -#define HAVE_AUX_XID > - > -/* We can assume that the kernel always provides the AT_SECURE value > - in the auxiliary vector from 2.5.74 or so on. */ > -#define HAVE_AUX_SECURE > - > -/* Starting with one of the 2.4.0 pre-releases the Linux kernel passes > - up the page size information. */ > -#define HAVE_AUX_PAGESIZE > - > #endif /* ldsodefs.h */ ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v2 3/5] Linux: Remove DL_FIND_ARG_COMPONENTS 2022-02-03 11:08 [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups Florian Weimer 2022-02-03 11:08 ` [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version Florian Weimer 2022-02-03 11:08 ` [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE Florian Weimer @ 2022-02-03 11:08 ` Florian Weimer 2022-02-08 20:12 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 4/5] Linux: Assume that NEED_DL_SYSINFO_DSO is always defined Florian Weimer 2022-02-03 11:08 ` [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing Florian Weimer 4 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-03 11:08 UTC (permalink / raw) To: libc-alpha The generic definition is always used since the Native Client port has been removed. --- sysdeps/unix/sysv/linux/dl-sysdep.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index 72aa109f2f..a13e0ea7ad 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -59,19 +59,6 @@ void *__libc_stack_end attribute_relro = NULL; rtld_hidden_data_def(__libc_stack_end) void *_dl_random attribute_relro = NULL; -#ifndef DL_FIND_ARG_COMPONENTS -# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ - do { \ - void **_tmp; \ - (argc) = *(long int *) cookie; \ - (argv) = (char **) ((long int *) cookie + 1); \ - (envp) = (argv) + (argc) + 1; \ - for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ - continue; \ - (auxp) = (void *) ++_tmp; \ - } while (0) -#endif - #ifndef DL_STACK_END # define DL_STACK_END(cookie) ((void *) (cookie)) #endif @@ -90,8 +77,16 @@ _dl_sysdep_start (void **start_argptr, #endif __libc_stack_end = DL_STACK_END (start_argptr); - DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ, - GLRO(dl_auxv)); + _dl_argc = (intptr_t) *start_argptr; + _dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */ + _environ = _dl_argv + _dl_argc + 1; + for (char **tmp = _environ + 1; ; ++tmp) + if (*tmp == NULL) + { + /* Another necessary aliasing violation. */ + GLRO(dl_auxv) = (ElfW(auxv_t) *) (tmp + 1); + break; + } user_entry = (ElfW(Addr)) ENTRY_POINT; GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ -- 2.34.1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 3/5] Linux: Remove DL_FIND_ARG_COMPONENTS 2022-02-03 11:08 ` [PATCH v2 3/5] Linux: Remove DL_FIND_ARG_COMPONENTS Florian Weimer @ 2022-02-08 20:12 ` Adhemerval Zanella 0 siblings, 0 replies; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-08 20:12 UTC (permalink / raw) To: Florian Weimer, libc-alpha On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote: > The generic definition is always used since the Native Client > port has been removed. LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > sysdeps/unix/sysv/linux/dl-sysdep.c | 25 ++++++++++--------------- > 1 file changed, 10 insertions(+), 15 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c > index 72aa109f2f..a13e0ea7ad 100644 > --- a/sysdeps/unix/sysv/linux/dl-sysdep.c > +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c > @@ -59,19 +59,6 @@ void *__libc_stack_end attribute_relro = NULL; > rtld_hidden_data_def(__libc_stack_end) > void *_dl_random attribute_relro = NULL; > > -#ifndef DL_FIND_ARG_COMPONENTS > -# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ > - do { \ > - void **_tmp; \ > - (argc) = *(long int *) cookie; \ > - (argv) = (char **) ((long int *) cookie + 1); \ > - (envp) = (argv) + (argc) + 1; \ > - for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ > - continue; \ > - (auxp) = (void *) ++_tmp; \ > - } while (0) > -#endif > - > #ifndef DL_STACK_END > # define DL_STACK_END(cookie) ((void *) (cookie)) > #endif > @@ -90,8 +77,16 @@ _dl_sysdep_start (void **start_argptr, > #endif > > __libc_stack_end = DL_STACK_END (start_argptr); > - DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ, > - GLRO(dl_auxv)); > + _dl_argc = (intptr_t) *start_argptr; > + _dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */ > + _environ = _dl_argv + _dl_argc + 1; > + for (char **tmp = _environ + 1; ; ++tmp) > + if (*tmp == NULL) > + { > + /* Another necessary aliasing violation. */ > + GLRO(dl_auxv) = (ElfW(auxv_t) *) (tmp + 1); > + break; > + } > > user_entry = (ElfW(Addr)) ENTRY_POINT; > GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v2 4/5] Linux: Assume that NEED_DL_SYSINFO_DSO is always defined 2022-02-03 11:08 [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups Florian Weimer ` (2 preceding siblings ...) 2022-02-03 11:08 ` [PATCH v2 3/5] Linux: Remove DL_FIND_ARG_COMPONENTS Florian Weimer @ 2022-02-03 11:08 ` Florian Weimer 2022-02-08 20:13 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing Florian Weimer 4 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-03 11:08 UTC (permalink / raw) To: libc-alpha The definition itself is still needed for generic code. --- sysdeps/unix/sysv/linux/dl-sysdep.c | 8 ++------ sysdeps/unix/sysv/linux/m68k/sysdep.h | 4 +--- 2 files changed, 3 insertions(+), 9 deletions(-) diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index a13e0ea7ad..2bda76b820 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -134,11 +134,9 @@ _dl_sysdep_start (void **start_argptr, new_sysinfo = av->a_un.a_val; break; #endif -#ifdef NEED_DL_SYSINFO_DSO case AT_SYSINFO_EHDR: GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; break; -#endif case AT_RANDOM: _dl_random = (void *) av->a_un.a_val; break; @@ -153,10 +151,8 @@ _dl_sysdep_start (void **start_argptr, #ifdef NEED_DL_SYSINFO if (new_sysinfo != 0) { -# ifdef NEED_DL_SYSINFO_DSO /* Only set the sysinfo value if we also have the vsyscall DSO. */ if (GLRO(dl_sysinfo_dso) != 0) -# endif GLRO(dl_sysinfo) = new_sysinfo; } #endif @@ -309,7 +305,7 @@ int attribute_hidden _dl_discover_osversion (void) { -#if defined NEED_DL_SYSINFO_DSO && defined SHARED +#ifdef SHARED if (GLRO(dl_sysinfo_map) != NULL) { /* If the kernel-supplied DSO contains a note indicating the kernel's @@ -340,7 +336,7 @@ _dl_discover_osversion (void) } } } -#endif +#endif /* SHARED */ char bufmem[64]; char *buf = bufmem; diff --git a/sysdeps/unix/sysv/linux/m68k/sysdep.h b/sysdeps/unix/sysv/linux/m68k/sysdep.h index 628e1be835..d87892a377 100644 --- a/sysdeps/unix/sysv/linux/m68k/sysdep.h +++ b/sysdeps/unix/sysv/linux/m68k/sysdep.h @@ -299,8 +299,6 @@ SYSCALL_ERROR_LABEL: \ #define PTR_MANGLE(var) (void) (var) #define PTR_DEMANGLE(var) (void) (var) -#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO /* M68K needs system-supplied DSO to access TLS helpers even when statically linked. */ -# define NEED_STATIC_SYSINFO_DSO 1 -#endif +#define NEED_STATIC_SYSINFO_DSO 1 -- 2.34.1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 4/5] Linux: Assume that NEED_DL_SYSINFO_DSO is always defined 2022-02-03 11:08 ` [PATCH v2 4/5] Linux: Assume that NEED_DL_SYSINFO_DSO is always defined Florian Weimer @ 2022-02-08 20:13 ` Adhemerval Zanella 0 siblings, 0 replies; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-08 20:13 UTC (permalink / raw) To: Florian Weimer, libc-alpha On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote: > The definition itself is still needed for generic code. LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > sysdeps/unix/sysv/linux/dl-sysdep.c | 8 ++------ > sysdeps/unix/sysv/linux/m68k/sysdep.h | 4 +--- > 2 files changed, 3 insertions(+), 9 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c > index a13e0ea7ad..2bda76b820 100644 > --- a/sysdeps/unix/sysv/linux/dl-sysdep.c > +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c > @@ -134,11 +134,9 @@ _dl_sysdep_start (void **start_argptr, > new_sysinfo = av->a_un.a_val; > break; > #endif > -#ifdef NEED_DL_SYSINFO_DSO > case AT_SYSINFO_EHDR: > GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; > break; > -#endif > case AT_RANDOM: > _dl_random = (void *) av->a_un.a_val; > break; > @@ -153,10 +151,8 @@ _dl_sysdep_start (void **start_argptr, > #ifdef NEED_DL_SYSINFO > if (new_sysinfo != 0) > { > -# ifdef NEED_DL_SYSINFO_DSO > /* Only set the sysinfo value if we also have the vsyscall DSO. */ > if (GLRO(dl_sysinfo_dso) != 0) > -# endif > GLRO(dl_sysinfo) = new_sysinfo; > } > #endif > @@ -309,7 +305,7 @@ int > attribute_hidden > _dl_discover_osversion (void) > { > -#if defined NEED_DL_SYSINFO_DSO && defined SHARED > +#ifdef SHARED > if (GLRO(dl_sysinfo_map) != NULL) > { > /* If the kernel-supplied DSO contains a note indicating the kernel's > @@ -340,7 +336,7 @@ _dl_discover_osversion (void) > } > } > } > -#endif > +#endif /* SHARED */ > > char bufmem[64]; > char *buf = bufmem; > diff --git a/sysdeps/unix/sysv/linux/m68k/sysdep.h b/sysdeps/unix/sysv/linux/m68k/sysdep.h > index 628e1be835..d87892a377 100644 > --- a/sysdeps/unix/sysv/linux/m68k/sysdep.h > +++ b/sysdeps/unix/sysv/linux/m68k/sysdep.h > @@ -299,8 +299,6 @@ SYSCALL_ERROR_LABEL: \ > #define PTR_MANGLE(var) (void) (var) > #define PTR_DEMANGLE(var) (void) (var) > > -#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO > /* M68K needs system-supplied DSO to access TLS helpers > even when statically linked. */ > -# define NEED_STATIC_SYSINFO_DSO 1 > -#endif > +#define NEED_STATIC_SYSINFO_DSO 1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-03 11:08 [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups Florian Weimer ` (3 preceding siblings ...) 2022-02-03 11:08 ` [PATCH v2 4/5] Linux: Assume that NEED_DL_SYSINFO_DSO is always defined Florian Weimer @ 2022-02-03 11:08 ` Florian Weimer 2022-02-08 20:19 ` Adhemerval Zanella 2022-02-11 12:31 ` Szabolcs Nagy 4 siblings, 2 replies; 30+ messages in thread From: Florian Weimer @ 2022-02-03 11:08 UTC (permalink / raw) To: libc-alpha And optimize it slightly. The large switch statement in _dl_sysdep_start can be replaced with a large array. This reduces source code and binary size. On i686-linux-gnu: Before: text data bss dec hex filename 7791 12 0 7803 1e7b elf/dl-sysdep.os After: text data bss dec hex filename 7135 12 0 7147 1beb elf/dl-sysdep.os --- elf/dl-support.c | 80 +------------ sysdeps/unix/sysv/linux/alpha/dl-auxv.h | 18 +-- sysdeps/unix/sysv/linux/dl-parse_auxv.h | 61 ++++++++++ sysdeps/unix/sysv/linux/dl-sysdep.c | 111 ++++++------------- sysdeps/unix/sysv/linux/powerpc/dl-auxv.h | 14 +-- sysdeps/unix/sysv/linux/powerpc/dl-support.c | 4 + 6 files changed, 107 insertions(+), 181 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/dl-parse_auxv.h create mode 100644 sysdeps/unix/sysv/linux/powerpc/dl-support.c diff --git a/elf/dl-support.c b/elf/dl-support.c index fb64765537..0fff62064a 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -241,93 +241,21 @@ __rtld_lock_define_initialized_recursive (, _dl_load_tls_lock) #ifdef HAVE_AUX_VECTOR +#include <dl-parse_auxv.h> + int _dl_clktck; void _dl_aux_init (ElfW(auxv_t) *av) { - int seen = 0; - uid_t uid = 0; - gid_t gid = 0; - #ifdef NEED_DL_SYSINFO /* NB: Avoid RELATIVE relocation in static PIE. */ GL(dl_sysinfo) = DL_SYSINFO_DEFAULT; #endif _dl_auxv = av; - for (; av->a_type != AT_NULL; ++av) - switch (av->a_type) - { - case AT_PAGESZ: - if (av->a_un.a_val != 0) - GLRO(dl_pagesize) = av->a_un.a_val; - break; - case AT_CLKTCK: - GLRO(dl_clktck) = av->a_un.a_val; - break; - case AT_PHDR: - GL(dl_phdr) = (const void *) av->a_un.a_val; - break; - case AT_PHNUM: - GL(dl_phnum) = av->a_un.a_val; - break; - case AT_PLATFORM: - GLRO(dl_platform) = (void *) av->a_un.a_val; - break; - case AT_HWCAP: - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; - break; - case AT_HWCAP2: - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; - break; - case AT_FPUCW: - GLRO(dl_fpu_control) = av->a_un.a_val; - break; -#ifdef NEED_DL_SYSINFO - case AT_SYSINFO: - GL(dl_sysinfo) = av->a_un.a_val; - break; -#endif -#ifdef NEED_DL_SYSINFO_DSO - case AT_SYSINFO_EHDR: - GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; - break; -#endif - case AT_UID: - uid ^= av->a_un.a_val; - seen |= 1; - break; - case AT_EUID: - uid ^= av->a_un.a_val; - seen |= 2; - break; - case AT_GID: - gid ^= av->a_un.a_val; - seen |= 4; - break; - case AT_EGID: - gid ^= av->a_un.a_val; - seen |= 8; - break; - case AT_SECURE: - seen = -1; - __libc_enable_secure = av->a_un.a_val; - __libc_enable_secure_decided = 1; - break; - case AT_RANDOM: - _dl_random = (void *) av->a_un.a_val; - break; - case AT_MINSIGSTKSZ: - _dl_minsigstacksize = av->a_un.a_val; - break; - DL_PLATFORM_AUXV - } - if (seen == 0xf) - { - __libc_enable_secure = uid != 0 || gid != 0; - __libc_enable_secure_decided = 1; - } + dl_parse_auxv_t auxv_values = { 0, }; + _dl_parse_auxv (av, auxv_values); } #endif diff --git a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h index 81d90da095..fcec743239 100644 --- a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h +++ b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h @@ -20,16 +20,8 @@ extern long __libc_alpha_cache_shape[4]; -#define DL_PLATFORM_AUXV \ - case AT_L1I_CACHESHAPE: \ - __libc_alpha_cache_shape[0] = av->a_un.a_val; \ - break; \ - case AT_L1D_CACHESHAPE: \ - __libc_alpha_cache_shape[1] = av->a_un.a_val; \ - break; \ - case AT_L2_CACHESHAPE: \ - __libc_alpha_cache_shape[2] = av->a_un.a_val; \ - break; \ - case AT_L3_CACHESHAPE: \ - __libc_alpha_cache_shape[3] = av->a_un.a_val; \ - break; +#define DL_PLATFORM_AUXV \ + __libc_alpha_cache_shape[0] = auxv_values[AT_L1I_CACHESHAPE]; \ + __libc_alpha_cache_shape[1] = auxv_values[AT_L1D_CACHESHAPE]; \ + __libc_alpha_cache_shape[2] = auxv_values[AT_L2_CACHESHAPE]; \ + __libc_alpha_cache_shape[3] = auxv_values[AT_L3_CACHESHAPE]; diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h new file mode 100644 index 0000000000..f450c6c5ce --- /dev/null +++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h @@ -0,0 +1,61 @@ +/* Parse the Linux auxiliary vector. + Copyright (C) 1995-2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <elf.h> +#include <entry.h> +#include <fpu_control.h> +#include <ldsodefs.h> +#include <link.h> + +typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1]; + +/* Copy the auxiliary vector into AUX_VALUES and set up GLRO + variables. */ +static inline +void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values) +{ + auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT; + auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; + auxv_values[AT_FPUCW] = _FPU_DEFAULT; + + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), + "CONSTANT_MINSIGSTKSZ is constant"); + auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ; + + for (; av->a_type != AT_NULL; av++) + if (av->a_type <= AT_MINSIGSTKSZ) + auxv_values[av->a_type] = av->a_un.a_val; + + GLRO(dl_pagesize) = auxv_values[AT_PAGESZ]; + __libc_enable_secure = auxv_values[AT_SECURE]; + GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM]; + GLRO(dl_hwcap) = auxv_values[AT_HWCAP]; + GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2]; + GLRO(dl_clktck) = auxv_values[AT_CLKTCK]; + GLRO(dl_fpu_control) = auxv_values[AT_FPUCW]; + _dl_random = (void *) auxv_values[AT_RANDOM]; + GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ]; + GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR]; +#ifdef NEED_DL_SYSINFO + if (GLRO(dl_sysinfo_dso) != NULL) + GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO]; +#endif + + DL_PLATFORM_AUXV +} diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index 2bda76b820..71cf1968b5 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -21,13 +21,12 @@ #include <dl-auxv.h> #include <dl-hwcap-check.h> #include <dl-osinfo.h> +#include <dl-parse_auxv.h> #include <dl-procinfo.h> #include <dl-tunables.h> #include <elf.h> -#include <entry.h> #include <errno.h> #include <fcntl.h> -#include <fpu_control.h> #include <ldsodefs.h> #include <libc-internal.h> #include <libintl.h> @@ -63,24 +62,24 @@ void *_dl_random attribute_relro = NULL; # define DL_STACK_END(cookie) ((void *) (cookie)) #endif -ElfW(Addr) -_dl_sysdep_start (void **start_argptr, - void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, - ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) +/* Arguments passed to dl_main. */ +struct dl_main_arguments { - const ElfW(Phdr) *phdr = NULL; - ElfW(Word) phnum = 0; + const ElfW(Phdr) *phdr; + ElfW(Word) phnum; ElfW(Addr) user_entry; - ElfW(auxv_t) *av; -#ifdef NEED_DL_SYSINFO - uintptr_t new_sysinfo = 0; -#endif +}; - __libc_stack_end = DL_STACK_END (start_argptr); +/* Separate function, so that dl_main can be called without the large + array on the stack. */ +static void +_dl_sysdep_parse_arguments (void **start_argptr, + struct dl_main_arguments *args) +{ _dl_argc = (intptr_t) *start_argptr; _dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */ _environ = _dl_argv + _dl_argc + 1; - for (char **tmp = _environ + 1; ; ++tmp) + for (char **tmp = _environ; ; ++tmp) if (*tmp == NULL) { /* Another necessary aliasing violation. */ @@ -88,74 +87,25 @@ _dl_sysdep_start (void **start_argptr, break; } - user_entry = (ElfW(Addr)) ENTRY_POINT; - GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ + dl_parse_auxv_t auxv_values = { 0, }; + _dl_parse_auxv (GLRO(dl_auxv), auxv_values); - /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ - _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), - "CONSTANT_MINSIGSTKSZ is constant"); - GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; + args->phdr = (const ElfW(Phdr) *) auxv_values[AT_PHDR]; + args->phnum = auxv_values[AT_PHNUM]; + args->user_entry = auxv_values[AT_ENTRY]; +} - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++) - switch (av->a_type) - { - case AT_PHDR: - phdr = (void *) av->a_un.a_val; - break; - case AT_PHNUM: - phnum = av->a_un.a_val; - break; - case AT_PAGESZ: - GLRO(dl_pagesize) = av->a_un.a_val; - break; - case AT_ENTRY: - user_entry = av->a_un.a_val; - break; - case AT_SECURE: - __libc_enable_secure = av->a_un.a_val; - break; - case AT_PLATFORM: - GLRO(dl_platform) = (void *) av->a_un.a_val; - break; - case AT_HWCAP: - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; - break; - case AT_HWCAP2: - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; - break; - case AT_CLKTCK: - GLRO(dl_clktck) = av->a_un.a_val; - break; - case AT_FPUCW: - GLRO(dl_fpu_control) = av->a_un.a_val; - break; -#ifdef NEED_DL_SYSINFO - case AT_SYSINFO: - new_sysinfo = av->a_un.a_val; - break; -#endif - case AT_SYSINFO_EHDR: - GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; - break; - case AT_RANDOM: - _dl_random = (void *) av->a_un.a_val; - break; - case AT_MINSIGSTKSZ: - GLRO(dl_minsigstacksize) = av->a_un.a_val; - break; - DL_PLATFORM_AUXV - } +ElfW(Addr) +_dl_sysdep_start (void **start_argptr, + void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, + ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) +{ + __libc_stack_end = DL_STACK_END (start_argptr); - dl_hwcap_check (); + struct dl_main_arguments dl_main_args; + _dl_sysdep_parse_arguments (start_argptr, &dl_main_args); -#ifdef NEED_DL_SYSINFO - if (new_sysinfo != 0) - { - /* Only set the sysinfo value if we also have the vsyscall DSO. */ - if (GLRO(dl_sysinfo_dso) != 0) - GLRO(dl_sysinfo) = new_sysinfo; - } -#endif + dl_hwcap_check (); __tunables_init (_environ); @@ -187,8 +137,9 @@ _dl_sysdep_start (void **start_argptr, if (__builtin_expect (__libc_enable_secure, 0)) __libc_check_standard_fds (); - (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv)); - return user_entry; + (*dl_main) (dl_main_args.phdr, dl_main_args.phnum, + &dl_main_args.user_entry, GLRO(dl_auxv)); + return dl_main_args.user_entry; } void diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h index 594371940a..ce2281cf11 100644 --- a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h +++ b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h @@ -16,15 +16,5 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -#include <ldsodefs.h> - -#if IS_IN (libc) && !defined SHARED -int GLRO(dl_cache_line_size); -#endif - -/* Scan the Aux Vector for the "Data Cache Block Size" entry and assign it - to dl_cache_line_size. */ -#define DL_PLATFORM_AUXV \ - case AT_DCACHEBSIZE: \ - GLRO(dl_cache_line_size) = av->a_un.a_val; \ - break; +#define DL_PLATFORM_AUXV \ + GLRO(dl_cache_line_size) = auxv_values[AT_DCACHEBSIZE]; diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-support.c b/sysdeps/unix/sysv/linux/powerpc/dl-support.c new file mode 100644 index 0000000000..abe68a7049 --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/dl-support.c @@ -0,0 +1,4 @@ +#include <elf/dl-support.c> + +/* Populated from the auxiliary vector. */ +int _dl_cache_line_size; -- 2.34.1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-03 11:08 ` [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing Florian Weimer @ 2022-02-08 20:19 ` Adhemerval Zanella 2022-02-08 20:34 ` Florian Weimer 2022-02-11 12:31 ` Szabolcs Nagy 1 sibling, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-08 20:19 UTC (permalink / raw) To: Florian Weimer, libc-alpha On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote: > And optimize it slightly. > > The large switch statement in _dl_sysdep_start can be replaced with > a large array. This reduces source code and binary size. On > i686-linux-gnu: > > Before: > > text data bss dec hex filename > 7791 12 0 7803 1e7b elf/dl-sysdep.os > > After: > > text data bss dec hex filename > 7135 12 0 7147 1beb elf/dl-sysdep.os LGTM with a couple comments below. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > elf/dl-support.c | 80 +------------ > sysdeps/unix/sysv/linux/alpha/dl-auxv.h | 18 +-- > sysdeps/unix/sysv/linux/dl-parse_auxv.h | 61 ++++++++++ > sysdeps/unix/sysv/linux/dl-sysdep.c | 111 ++++++------------- > sysdeps/unix/sysv/linux/powerpc/dl-auxv.h | 14 +-- > sysdeps/unix/sysv/linux/powerpc/dl-support.c | 4 + > 6 files changed, 107 insertions(+), 181 deletions(-) > create mode 100644 sysdeps/unix/sysv/linux/dl-parse_auxv.h > create mode 100644 sysdeps/unix/sysv/linux/powerpc/dl-support.c > > diff --git a/elf/dl-support.c b/elf/dl-support.c > index fb64765537..0fff62064a 100644 > --- a/elf/dl-support.c > +++ b/elf/dl-support.c > @@ -241,93 +241,21 @@ __rtld_lock_define_initialized_recursive (, _dl_load_tls_lock) > > > #ifdef HAVE_AUX_VECTOR > +#include <dl-parse_auxv.h> > + > int _dl_clktck; > > void > _dl_aux_init (ElfW(auxv_t) *av) > { > - int seen = 0; > - uid_t uid = 0; > - gid_t gid = 0; > - > #ifdef NEED_DL_SYSINFO > /* NB: Avoid RELATIVE relocation in static PIE. */ > GL(dl_sysinfo) = DL_SYSINFO_DEFAULT; > #endif > > _dl_auxv = av; > - for (; av->a_type != AT_NULL; ++av) > - switch (av->a_type) > - { > - case AT_PAGESZ: > - if (av->a_un.a_val != 0) > - GLRO(dl_pagesize) = av->a_un.a_val; > - break; > - case AT_CLKTCK: > - GLRO(dl_clktck) = av->a_un.a_val; > - break; > - case AT_PHDR: > - GL(dl_phdr) = (const void *) av->a_un.a_val; > - break; > - case AT_PHNUM: > - GL(dl_phnum) = av->a_un.a_val; > - break; > - case AT_PLATFORM: > - GLRO(dl_platform) = (void *) av->a_un.a_val; > - break; > - case AT_HWCAP: > - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_HWCAP2: > - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_FPUCW: > - GLRO(dl_fpu_control) = av->a_un.a_val; > - break; > -#ifdef NEED_DL_SYSINFO > - case AT_SYSINFO: > - GL(dl_sysinfo) = av->a_un.a_val; > - break; > -#endif > -#ifdef NEED_DL_SYSINFO_DSO > - case AT_SYSINFO_EHDR: > - GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; > - break; > -#endif > - case AT_UID: > - uid ^= av->a_un.a_val; > - seen |= 1; > - break; > - case AT_EUID: > - uid ^= av->a_un.a_val; > - seen |= 2; > - break; > - case AT_GID: > - gid ^= av->a_un.a_val; > - seen |= 4; > - break; > - case AT_EGID: > - gid ^= av->a_un.a_val; > - seen |= 8; > - break; > - case AT_SECURE: > - seen = -1; > - __libc_enable_secure = av->a_un.a_val; > - __libc_enable_secure_decided = 1; > - break; > - case AT_RANDOM: > - _dl_random = (void *) av->a_un.a_val; > - break; > - case AT_MINSIGSTKSZ: > - _dl_minsigstacksize = av->a_un.a_val; > - break; > - DL_PLATFORM_AUXV > - } > - if (seen == 0xf) > - { > - __libc_enable_secure = uid != 0 || gid != 0; > - __libc_enable_secure_decided = 1; > - } > + dl_parse_auxv_t auxv_values = { 0, }; > + _dl_parse_auxv (av, auxv_values); > } > #endif > > diff --git a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h > index 81d90da095..fcec743239 100644 > --- a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h > +++ b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h > @@ -20,16 +20,8 @@ > > extern long __libc_alpha_cache_shape[4]; > > -#define DL_PLATFORM_AUXV \ > - case AT_L1I_CACHESHAPE: \ > - __libc_alpha_cache_shape[0] = av->a_un.a_val; \ > - break; \ > - case AT_L1D_CACHESHAPE: \ > - __libc_alpha_cache_shape[1] = av->a_un.a_val; \ > - break; \ > - case AT_L2_CACHESHAPE: \ > - __libc_alpha_cache_shape[2] = av->a_un.a_val; \ > - break; \ > - case AT_L3_CACHESHAPE: \ > - __libc_alpha_cache_shape[3] = av->a_un.a_val; \ > - break; > +#define DL_PLATFORM_AUXV \ > + __libc_alpha_cache_shape[0] = auxv_values[AT_L1I_CACHESHAPE]; \ > + __libc_alpha_cache_shape[1] = auxv_values[AT_L1D_CACHESHAPE]; \ > + __libc_alpha_cache_shape[2] = auxv_values[AT_L2_CACHESHAPE]; \ > + __libc_alpha_cache_shape[3] = auxv_values[AT_L3_CACHESHAPE]; > diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h > new file mode 100644 > index 0000000000..f450c6c5ce > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h > @@ -0,0 +1,61 @@ > +/* Parse the Linux auxiliary vector. > + Copyright (C) 1995-2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <https://www.gnu.org/licenses/>. */ > + > +#include <elf.h> > +#include <entry.h> > +#include <fpu_control.h> > +#include <ldsodefs.h> > +#include <link.h> > + > +typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1]; > + > +/* Copy the auxiliary vector into AUX_VALUES and set up GLRO > + variables. */ > +static inline > +void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values) > +{ > + auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT; Extra whitespace. > + auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; > + auxv_values[AT_FPUCW] = _FPU_DEFAULT; > + > + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ > + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), > + "CONSTANT_MINSIGSTKSZ is constant"); Shouldn't it warn that CONSTANT_MINSIGSTKSZ is not a constant? > + auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ; > + > + for (; av->a_type != AT_NULL; av++) > + if (av->a_type <= AT_MINSIGSTKSZ) > + auxv_values[av->a_type] = av->a_un.a_val; > + > + GLRO(dl_pagesize) = auxv_values[AT_PAGESZ]; > + __libc_enable_secure = auxv_values[AT_SECURE]; > + GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM]; > + GLRO(dl_hwcap) = auxv_values[AT_HWCAP]; > + GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2]; > + GLRO(dl_clktck) = auxv_values[AT_CLKTCK]; > + GLRO(dl_fpu_control) = auxv_values[AT_FPUCW]; > + _dl_random = (void *) auxv_values[AT_RANDOM]; > + GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ]; > + GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR]; > +#ifdef NEED_DL_SYSINFO I think you can now assume NEED_DL_SYSINFO is always defined. > + if (GLRO(dl_sysinfo_dso) != NULL) > + GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO]; > +#endif > + > + DL_PLATFORM_AUXV > +} > diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c > index 2bda76b820..71cf1968b5 100644 > --- a/sysdeps/unix/sysv/linux/dl-sysdep.c > +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c > @@ -21,13 +21,12 @@ > #include <dl-auxv.h> > #include <dl-hwcap-check.h> > #include <dl-osinfo.h> > +#include <dl-parse_auxv.h> > #include <dl-procinfo.h> > #include <dl-tunables.h> > #include <elf.h> > -#include <entry.h> > #include <errno.h> > #include <fcntl.h> > -#include <fpu_control.h> > #include <ldsodefs.h> > #include <libc-internal.h> > #include <libintl.h> > @@ -63,24 +62,24 @@ void *_dl_random attribute_relro = NULL; > # define DL_STACK_END(cookie) ((void *) (cookie)) > #endif > > -ElfW(Addr) > -_dl_sysdep_start (void **start_argptr, > - void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, > - ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) > +/* Arguments passed to dl_main. */ > +struct dl_main_arguments > { > - const ElfW(Phdr) *phdr = NULL; > - ElfW(Word) phnum = 0; > + const ElfW(Phdr) *phdr; > + ElfW(Word) phnum; > ElfW(Addr) user_entry; > - ElfW(auxv_t) *av; > -#ifdef NEED_DL_SYSINFO > - uintptr_t new_sysinfo = 0; > -#endif > +}; > > - __libc_stack_end = DL_STACK_END (start_argptr); > +/* Separate function, so that dl_main can be called without the large > + array on the stack. */ > +static void > +_dl_sysdep_parse_arguments (void **start_argptr, > + struct dl_main_arguments *args) > +{ > _dl_argc = (intptr_t) *start_argptr; > _dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */ > _environ = _dl_argv + _dl_argc + 1; > - for (char **tmp = _environ + 1; ; ++tmp) > + for (char **tmp = _environ; ; ++tmp) > if (*tmp == NULL) > { > /* Another necessary aliasing violation. */ > @@ -88,74 +87,25 @@ _dl_sysdep_start (void **start_argptr, > break; > } > > - user_entry = (ElfW(Addr)) ENTRY_POINT; > - GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ > + dl_parse_auxv_t auxv_values = { 0, }; > + _dl_parse_auxv (GLRO(dl_auxv), auxv_values); > > - /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ > - _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), > - "CONSTANT_MINSIGSTKSZ is constant"); > - GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ; > + args->phdr = (const ElfW(Phdr) *) auxv_values[AT_PHDR]; > + args->phnum = auxv_values[AT_PHNUM]; > + args->user_entry = auxv_values[AT_ENTRY]; > +} > > - for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++) > - switch (av->a_type) > - { > - case AT_PHDR: > - phdr = (void *) av->a_un.a_val; > - break; > - case AT_PHNUM: > - phnum = av->a_un.a_val; > - break; > - case AT_PAGESZ: > - GLRO(dl_pagesize) = av->a_un.a_val; > - break; > - case AT_ENTRY: > - user_entry = av->a_un.a_val; > - break; > - case AT_SECURE: > - __libc_enable_secure = av->a_un.a_val; > - break; > - case AT_PLATFORM: > - GLRO(dl_platform) = (void *) av->a_un.a_val; > - break; > - case AT_HWCAP: > - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_HWCAP2: > - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_CLKTCK: > - GLRO(dl_clktck) = av->a_un.a_val; > - break; > - case AT_FPUCW: > - GLRO(dl_fpu_control) = av->a_un.a_val; > - break; > -#ifdef NEED_DL_SYSINFO > - case AT_SYSINFO: > - new_sysinfo = av->a_un.a_val; > - break; > -#endif > - case AT_SYSINFO_EHDR: > - GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; > - break; > - case AT_RANDOM: > - _dl_random = (void *) av->a_un.a_val; > - break; > - case AT_MINSIGSTKSZ: > - GLRO(dl_minsigstacksize) = av->a_un.a_val; > - break; > - DL_PLATFORM_AUXV > - } > +ElfW(Addr) > +_dl_sysdep_start (void **start_argptr, > + void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, > + ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) > +{ > + __libc_stack_end = DL_STACK_END (start_argptr); > > - dl_hwcap_check (); > + struct dl_main_arguments dl_main_args; > + _dl_sysdep_parse_arguments (start_argptr, &dl_main_args); > > -#ifdef NEED_DL_SYSINFO > - if (new_sysinfo != 0) > - { > - /* Only set the sysinfo value if we also have the vsyscall DSO. */ > - if (GLRO(dl_sysinfo_dso) != 0) > - GLRO(dl_sysinfo) = new_sysinfo; > - } > -#endif > + dl_hwcap_check (); > > __tunables_init (_environ); > > @@ -187,8 +137,9 @@ _dl_sysdep_start (void **start_argptr, > if (__builtin_expect (__libc_enable_secure, 0)) > __libc_check_standard_fds (); > > - (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv)); > - return user_entry; > + (*dl_main) (dl_main_args.phdr, dl_main_args.phnum, > + &dl_main_args.user_entry, GLRO(dl_auxv)); > + return dl_main_args.user_entry; > } > > void > diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h > index 594371940a..ce2281cf11 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h > +++ b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h > @@ -16,15 +16,5 @@ > License along with the GNU C Library; if not, see > <https://www.gnu.org/licenses/>. */ > > -#include <ldsodefs.h> > - > -#if IS_IN (libc) && !defined SHARED > -int GLRO(dl_cache_line_size); > -#endif > - > -/* Scan the Aux Vector for the "Data Cache Block Size" entry and assign it > - to dl_cache_line_size. */ > -#define DL_PLATFORM_AUXV \ > - case AT_DCACHEBSIZE: \ > - GLRO(dl_cache_line_size) = av->a_un.a_val; \ > - break; > +#define DL_PLATFORM_AUXV \ > + GLRO(dl_cache_line_size) = auxv_values[AT_DCACHEBSIZE]; > diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-support.c b/sysdeps/unix/sysv/linux/powerpc/dl-support.c > new file mode 100644 > index 0000000000..abe68a7049 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/powerpc/dl-support.c > @@ -0,0 +1,4 @@ > +#include <elf/dl-support.c> > + > +/* Populated from the auxiliary vector. */ > +int _dl_cache_line_size; ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-08 20:19 ` Adhemerval Zanella @ 2022-02-08 20:34 ` Florian Weimer 2022-02-08 22:57 ` Adhemerval Zanella 0 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-08 20:34 UTC (permalink / raw) To: Adhemerval Zanella; +Cc: libc-alpha * Adhemerval Zanella: >> diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h >> new file mode 100644 >> index 0000000000..f450c6c5ce >> --- /dev/null >> +++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h >> +typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1]; >> + >> +/* Copy the auxiliary vector into AUX_VALUES and set up GLRO >> + variables. */ >> +static inline >> +void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values) >> +{ >> + auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT; > > Extra whitespace. Fxied. >> + auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; >> + auxv_values[AT_FPUCW] = _FPU_DEFAULT; >> + >> + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ >> + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), >> + "CONSTANT_MINSIGSTKSZ is constant"); > > Shouldn't it warn that CONSTANT_MINSIGSTKSZ is not a constant? Sorry, would please rephrase? Should I change this to ""CONSTANT_MINSIGSTKSZ is not constant"? >> + auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ; >> + >> + for (; av->a_type != AT_NULL; av++) >> + if (av->a_type <= AT_MINSIGSTKSZ) >> + auxv_values[av->a_type] = av->a_un.a_val; >> + >> + GLRO(dl_pagesize) = auxv_values[AT_PAGESZ]; >> + __libc_enable_secure = auxv_values[AT_SECURE]; >> + GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM]; >> + GLRO(dl_hwcap) = auxv_values[AT_HWCAP]; >> + GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2]; >> + GLRO(dl_clktck) = auxv_values[AT_CLKTCK]; >> + GLRO(dl_fpu_control) = auxv_values[AT_FPUCW]; >> + _dl_random = (void *) auxv_values[AT_RANDOM]; >> + GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ]; >> + GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR]; >> +#ifdef NEED_DL_SYSINFO > > I think you can now assume NEED_DL_SYSINFO is always defined. NEED_DL_SYSINFO is only defined by i386 and ia64, only NEED_DL_SYSINFO_DSO is always defined on Linux. Thanks, Florian ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-08 20:34 ` Florian Weimer @ 2022-02-08 22:57 ` Adhemerval Zanella 2022-02-10 10:54 ` Florian Weimer 0 siblings, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-08 22:57 UTC (permalink / raw) To: Florian Weimer; +Cc: libc-alpha On 08/02/2022 17:34, Florian Weimer wrote: > * Adhemerval Zanella: > >>> diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h >>> new file mode 100644 >>> index 0000000000..f450c6c5ce >>> --- /dev/null >>> +++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h > >>> +typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1]; >>> + >>> +/* Copy the auxiliary vector into AUX_VALUES and set up GLRO >>> + variables. */ >>> +static inline >>> +void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values) >>> +{ >>> + auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT; >> >> Extra whitespace. > > Fxied. > >>> + auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; >>> + auxv_values[AT_FPUCW] = _FPU_DEFAULT; >>> + >>> + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ >>> + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), >>> + "CONSTANT_MINSIGSTKSZ is constant"); >> >> Shouldn't it warn that CONSTANT_MINSIGSTKSZ is not a constant? > > Sorry, would please rephrase? Should I change this to > ""CONSTANT_MINSIGSTKSZ is not constant"? Yeah because on a the _Static_assert failure the resulting message seems to the opposite of what triggered it. > >>> + auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ; >>> + >>> + for (; av->a_type != AT_NULL; av++) >>> + if (av->a_type <= AT_MINSIGSTKSZ) >>> + auxv_values[av->a_type] = av->a_un.a_val; >>> + >>> + GLRO(dl_pagesize) = auxv_values[AT_PAGESZ]; >>> + __libc_enable_secure = auxv_values[AT_SECURE]; >>> + GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM]; >>> + GLRO(dl_hwcap) = auxv_values[AT_HWCAP]; >>> + GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2]; >>> + GLRO(dl_clktck) = auxv_values[AT_CLKTCK]; >>> + GLRO(dl_fpu_control) = auxv_values[AT_FPUCW]; >>> + _dl_random = (void *) auxv_values[AT_RANDOM]; >>> + GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ]; >>> + GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR]; >>> +#ifdef NEED_DL_SYSINFO >> >> I think you can now assume NEED_DL_SYSINFO is always defined. > > NEED_DL_SYSINFO is only defined by i386 and ia64, only > NEED_DL_SYSINFO_DSO is always defined on Linux. Indeed, my confusion here. > > Thanks, > Florian > ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-08 22:57 ` Adhemerval Zanella @ 2022-02-10 10:54 ` Florian Weimer 2022-02-10 11:29 ` Adhemerval Zanella 0 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-10 10:54 UTC (permalink / raw) To: Adhemerval Zanella; +Cc: libc-alpha * Adhemerval Zanella: >>>> + auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; >>>> + auxv_values[AT_FPUCW] = _FPU_DEFAULT; >>>> + >>>> + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ >>>> + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), >>>> + "CONSTANT_MINSIGSTKSZ is constant"); >>> >>> Shouldn't it warn that CONSTANT_MINSIGSTKSZ is not a constant? >> >> Sorry, would please rephrase? Should I change this to >> ""CONSTANT_MINSIGSTKSZ is not constant"? > > Yeah because on a the _Static_assert failure the resulting message seems > to the opposite of what triggered it. The GCC error message doesn't suggest a strong preference either way: /tmp/t.c:1:1: error: static assertion failed: "failed" 1 | _Static_assert (0, "failed"); | ^~~~~~~~~~~~~~ I think in the existing sources, the message is sometimes indicating the failure, or what is being asserted (as is the case here). Thanks, Florian ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-10 10:54 ` Florian Weimer @ 2022-02-10 11:29 ` Adhemerval Zanella 2022-02-10 11:31 ` Florian Weimer 0 siblings, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-10 11:29 UTC (permalink / raw) To: Florian Weimer; +Cc: libc-alpha On 10/02/2022 07:54, Florian Weimer wrote: > * Adhemerval Zanella: > >>>>> + auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; >>>>> + auxv_values[AT_FPUCW] = _FPU_DEFAULT; >>>>> + >>>>> + /* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */ >>>>> + _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), >>>>> + "CONSTANT_MINSIGSTKSZ is constant"); >>>> >>>> Shouldn't it warn that CONSTANT_MINSIGSTKSZ is not a constant? >>> >>> Sorry, would please rephrase? Should I change this to >>> ""CONSTANT_MINSIGSTKSZ is not constant"? >> >> Yeah because on a the _Static_assert failure the resulting message seems >> to the opposite of what triggered it. > > The GCC error message doesn't suggest a strong preference either way: > > /tmp/t.c:1:1: error: static assertion failed: "failed" > 1 | _Static_assert (0, "failed"); > | ^~~~~~~~~~~~~~ > > I think in the existing sources, the message is sometimes indicating the > failure, or what is being asserted (as is the case here). Compiler is will just emit the message if condition is met, my point is emitting 'CONSTANT_MINSIGSTKSZ is constant' on an error is the opposite of what triggered it (CONSTANT_MINSIGSTKSZ is really *not* a constant). ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-10 11:29 ` Adhemerval Zanella @ 2022-02-10 11:31 ` Florian Weimer 2022-02-10 11:40 ` Adhemerval Zanella 0 siblings, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-10 11:31 UTC (permalink / raw) To: Adhemerval Zanella; +Cc: libc-alpha * Adhemerval Zanella: >> The GCC error message doesn't suggest a strong preference either way: >> >> /tmp/t.c:1:1: error: static assertion failed: "failed" >> 1 | _Static_assert (0, "failed"); >> | ^~~~~~~~~~~~~~ >> >> I think in the existing sources, the message is sometimes indicating the >> failure, or what is being asserted (as is the case here). > > Compiler is will just emit the message if condition is met, my point is > emitting 'CONSTANT_MINSIGSTKSZ is constant' on an error is the opposite > of what triggered it (CONSTANT_MINSIGSTKSZ is really *not* a constant). But the check asserts that CONSTANT_MINSIGSTKSZ is constant, so the message is still correct. Thanks, Florian ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-10 11:31 ` Florian Weimer @ 2022-02-10 11:40 ` Adhemerval Zanella 2022-02-10 11:46 ` Adhemerval Zanella 0 siblings, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-10 11:40 UTC (permalink / raw) To: Florian Weimer; +Cc: libc-alpha On 10/02/2022 08:31, Florian Weimer wrote: > * Adhemerval Zanella: > >>> The GCC error message doesn't suggest a strong preference either way: >>> >>> /tmp/t.c:1:1: error: static assertion failed: "failed" >>> 1 | _Static_assert (0, "failed"); >>> | ^~~~~~~~~~~~~~ >>> >>> I think in the existing sources, the message is sometimes indicating the >>> failure, or what is being asserted (as is the case here). >> >> Compiler is will just emit the message if condition is met, my point is >> emitting 'CONSTANT_MINSIGSTKSZ is constant' on an error is the opposite >> of what triggered it (CONSTANT_MINSIGSTKSZ is really *not* a constant). > > But the check asserts that CONSTANT_MINSIGSTKSZ is constant, so the > message is still correct. In fact the _Static_assert does not really matter, __builtin_constant_p will already trigger a valid warning message: In file included from ../include/features.h:490, from ../posix/sys/types.h:25, from ../include/sys/types.h:1, from ../include/string.h:6, from dl-support.c:22: ../sysdeps/unix/sysv/linux/dl-parse_auxv.h: In function ‘_dl_parse_auxv’: ../sysdeps/unix/sysv/linux/dl-parse_auxv.h:40:19: error: expression in static assertion is not constant 40 | _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../include/sys/cdefs.h:7:59: note: in definition of macro ‘_Static_assert’ 7 | # define _Static_assert(expr, diagnostic) _Static_assert (expr, diagnostic) ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-10 11:40 ` Adhemerval Zanella @ 2022-02-10 11:46 ` Adhemerval Zanella 0 siblings, 0 replies; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-10 11:46 UTC (permalink / raw) To: Florian Weimer; +Cc: libc-alpha On 10/02/2022 08:40, Adhemerval Zanella wrote: > > > On 10/02/2022 08:31, Florian Weimer wrote: >> * Adhemerval Zanella: >> >>>> The GCC error message doesn't suggest a strong preference either way: >>>> >>>> /tmp/t.c:1:1: error: static assertion failed: "failed" >>>> 1 | _Static_assert (0, "failed"); >>>> | ^~~~~~~~~~~~~~ >>>> >>>> I think in the existing sources, the message is sometimes indicating the >>>> failure, or what is being asserted (as is the case here). >>> >>> Compiler is will just emit the message if condition is met, my point is >>> emitting 'CONSTANT_MINSIGSTKSZ is constant' on an error is the opposite >>> of what triggered it (CONSTANT_MINSIGSTKSZ is really *not* a constant). >> >> But the check asserts that CONSTANT_MINSIGSTKSZ is constant, so the >> message is still correct. > In fact the _Static_assert does not really matter, __builtin_constant_p _Static_assert message string* > will already trigger a valid warning message: > > In file included from ../include/features.h:490, > from ../posix/sys/types.h:25, > from ../include/sys/types.h:1, > from ../include/string.h:6, > from dl-support.c:22: > ../sysdeps/unix/sysv/linux/dl-parse_auxv.h: In function ‘_dl_parse_auxv’: > ../sysdeps/unix/sysv/linux/dl-parse_auxv.h:40:19: error: expression in static assertion is not constant > 40 | _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ), > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ../include/sys/cdefs.h:7:59: note: in definition of macro ‘_Static_assert’ > 7 | # define _Static_assert(expr, diagnostic) _Static_assert (expr, diagnostic) ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-03 11:08 ` [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing Florian Weimer 2022-02-08 20:19 ` Adhemerval Zanella @ 2022-02-11 12:31 ` Szabolcs Nagy 2022-02-11 12:47 ` Adhemerval Zanella 2022-02-11 17:32 ` Florian Weimer 1 sibling, 2 replies; 30+ messages in thread From: Szabolcs Nagy @ 2022-02-11 12:31 UTC (permalink / raw) To: Florian Weimer; +Cc: libc-alpha this broke aarch64 static binaries: The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote > void > _dl_aux_init (ElfW(auxv_t) *av) > { > - int seen = 0; > - uid_t uid = 0; > - gid_t gid = 0; > - > #ifdef NEED_DL_SYSINFO > /* NB: Avoid RELATIVE relocation in static PIE. */ > GL(dl_sysinfo) = DL_SYSINFO_DEFAULT; > #endif > > _dl_auxv = av; > - for (; av->a_type != AT_NULL; ++av) > - switch (av->a_type) > - { > - case AT_PAGESZ: > - if (av->a_un.a_val != 0) > - GLRO(dl_pagesize) = av->a_un.a_val; > - break; > - case AT_CLKTCK: > - GLRO(dl_clktck) = av->a_un.a_val; > - break; > - case AT_PHDR: > - GL(dl_phdr) = (const void *) av->a_un.a_val; > - break; > - case AT_PHNUM: > - GL(dl_phnum) = av->a_un.a_val; > - break; > - case AT_PLATFORM: > - GLRO(dl_platform) = (void *) av->a_un.a_val; > - break; > - case AT_HWCAP: > - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_HWCAP2: > - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; > - break; > - case AT_FPUCW: > - GLRO(dl_fpu_control) = av->a_un.a_val; > - break; > -#ifdef NEED_DL_SYSINFO > - case AT_SYSINFO: > - GL(dl_sysinfo) = av->a_un.a_val; > - break; > -#endif > -#ifdef NEED_DL_SYSINFO_DSO > - case AT_SYSINFO_EHDR: > - GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; > - break; > -#endif > - case AT_UID: > - uid ^= av->a_un.a_val; > - seen |= 1; > - break; > - case AT_EUID: > - uid ^= av->a_un.a_val; > - seen |= 2; > - break; > - case AT_GID: > - gid ^= av->a_un.a_val; > - seen |= 4; > - break; > - case AT_EGID: > - gid ^= av->a_un.a_val; > - seen |= 8; > - break; > - case AT_SECURE: > - seen = -1; > - __libc_enable_secure = av->a_un.a_val; > - __libc_enable_secure_decided = 1; > - break; > - case AT_RANDOM: > - _dl_random = (void *) av->a_un.a_val; > - break; > - case AT_MINSIGSTKSZ: > - _dl_minsigstacksize = av->a_un.a_val; > - break; > - DL_PLATFORM_AUXV > - } > - if (seen == 0xf) > - { > - __libc_enable_secure = uid != 0 || gid != 0; > - __libc_enable_secure_decided = 1; > - } > + dl_parse_auxv_t auxv_values = { 0, }; > + _dl_parse_auxv (av, auxv_values); this seems to use memset now on aarch64 before irelative relocs are resolved in static binaries. which causes infinite loops in the iplt (i've also seen segfaults in the build log). i wonder what is a clean fix... ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 12:31 ` Szabolcs Nagy @ 2022-02-11 12:47 ` Adhemerval Zanella 2022-02-11 13:24 ` Szabolcs Nagy 2022-02-11 17:32 ` Florian Weimer 1 sibling, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-11 12:47 UTC (permalink / raw) To: Szabolcs Nagy, Florian Weimer; +Cc: libc-alpha On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: > this broke aarch64 static binaries: > > The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote >> void >> _dl_aux_init (ElfW(auxv_t) *av) >> { >> - int seen = 0; >> - uid_t uid = 0; >> - gid_t gid = 0; >> - >> #ifdef NEED_DL_SYSINFO >> /* NB: Avoid RELATIVE relocation in static PIE. */ >> GL(dl_sysinfo) = DL_SYSINFO_DEFAULT; >> #endif >> >> _dl_auxv = av; >> - for (; av->a_type != AT_NULL; ++av) >> - switch (av->a_type) >> - { >> - case AT_PAGESZ: >> - if (av->a_un.a_val != 0) >> - GLRO(dl_pagesize) = av->a_un.a_val; >> - break; >> - case AT_CLKTCK: >> - GLRO(dl_clktck) = av->a_un.a_val; >> - break; >> - case AT_PHDR: >> - GL(dl_phdr) = (const void *) av->a_un.a_val; >> - break; >> - case AT_PHNUM: >> - GL(dl_phnum) = av->a_un.a_val; >> - break; >> - case AT_PLATFORM: >> - GLRO(dl_platform) = (void *) av->a_un.a_val; >> - break; >> - case AT_HWCAP: >> - GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; >> - break; >> - case AT_HWCAP2: >> - GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; >> - break; >> - case AT_FPUCW: >> - GLRO(dl_fpu_control) = av->a_un.a_val; >> - break; >> -#ifdef NEED_DL_SYSINFO >> - case AT_SYSINFO: >> - GL(dl_sysinfo) = av->a_un.a_val; >> - break; >> -#endif >> -#ifdef NEED_DL_SYSINFO_DSO >> - case AT_SYSINFO_EHDR: >> - GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; >> - break; >> -#endif >> - case AT_UID: >> - uid ^= av->a_un.a_val; >> - seen |= 1; >> - break; >> - case AT_EUID: >> - uid ^= av->a_un.a_val; >> - seen |= 2; >> - break; >> - case AT_GID: >> - gid ^= av->a_un.a_val; >> - seen |= 4; >> - break; >> - case AT_EGID: >> - gid ^= av->a_un.a_val; >> - seen |= 8; >> - break; >> - case AT_SECURE: >> - seen = -1; >> - __libc_enable_secure = av->a_un.a_val; >> - __libc_enable_secure_decided = 1; >> - break; >> - case AT_RANDOM: >> - _dl_random = (void *) av->a_un.a_val; >> - break; >> - case AT_MINSIGSTKSZ: >> - _dl_minsigstacksize = av->a_un.a_val; >> - break; >> - DL_PLATFORM_AUXV >> - } >> - if (seen == 0xf) >> - { >> - __libc_enable_secure = uid != 0 || gid != 0; >> - __libc_enable_secure_decided = 1; >> - } >> + dl_parse_auxv_t auxv_values = { 0, }; >> + _dl_parse_auxv (av, auxv_values); > > this seems to use memset now on aarch64 before irelative > relocs are resolved in static binaries. > > which causes infinite loops in the iplt (i've also seen > segfaults in the build log). > > i wonder what is a clean fix... > Maybe add inhibit_loop_to_libcall to avoid the memset call. ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 12:47 ` Adhemerval Zanella @ 2022-02-11 13:24 ` Szabolcs Nagy 2022-02-11 13:48 ` Adhemerval Zanella 2022-02-11 13:49 ` Florian Weimer 0 siblings, 2 replies; 30+ messages in thread From: Szabolcs Nagy @ 2022-02-11 13:24 UTC (permalink / raw) To: Adhemerval Zanella; +Cc: Florian Weimer, libc-alpha The 02/11/2022 09:47, Adhemerval Zanella wrote: > On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: > > The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote > >> + dl_parse_auxv_t auxv_values = { 0, }; > >> + _dl_parse_auxv (av, auxv_values); > > > > this seems to use memset now on aarch64 before irelative > > relocs are resolved in static binaries. > > > > which causes infinite loops in the iplt (i've also seen > > segfaults in the build log). > > > > i wonder what is a clean fix... > > > > Maybe add inhibit_loop_to_libcall to avoid the memset call. does not work for me.. happens at -O0 too https://godbolt.org/z/W9r3nffYd ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 13:24 ` Szabolcs Nagy @ 2022-02-11 13:48 ` Adhemerval Zanella 2022-02-11 14:42 ` H.J. Lu 2022-02-11 13:49 ` Florian Weimer 1 sibling, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-11 13:48 UTC (permalink / raw) To: Szabolcs Nagy; +Cc: Florian Weimer, libc-alpha On 11/02/2022 10:24, Szabolcs Nagy wrote: > The 02/11/2022 09:47, Adhemerval Zanella wrote: >> On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: >>> The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote >>>> + dl_parse_auxv_t auxv_values = { 0, }; >>>> + _dl_parse_auxv (av, auxv_values); >>> >>> this seems to use memset now on aarch64 before irelative >>> relocs are resolved in static binaries. >>> >>> which causes infinite loops in the iplt (i've also seen >>> segfaults in the build log). >>> >>> i wonder what is a clean fix... >>> >> >> Maybe add inhibit_loop_to_libcall to avoid the memset call. > > does not work for me.. > happens at -O0 too > https://godbolt.org/z/W9r3nffYd Yeah, this won't help much this situation. Unless we can make gcc *not* emit this memset call, we will need something like: diff --git a/elf/dl-support.c b/elf/dl-support.c index 1977a2be76..49f3fd2a61 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -19,6 +19,10 @@ /* This file defines some things that for the dynamic linker are defined in rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking. */ +#ifndef SHARED +asm ("memset = __memset_generic"); +#endif + #include <string.h> /* Mark symbols hidden in static PIE for early self relocation to work. Note: string.h may have ifuncs which cannot be hidden on i686. */ $ make -j24 && make test t=elf/tst-tls1-static-non-pie [...] PASS: elf/tst-tls1-static-non-pie original exit status 0 set bar to 1 (LE) get sum of foo and bar (IE) = 1 get sum of foo and bar (LD or TLSDESC) = 1 get sum of foo and bar (GD or TLSDESC) = 1 I think the best approach would to add a __memset_generic, __memcpy_generic, and __memmove_generic on all targets and add a header similar to sysdeps/generic/symbol-hacks.h to activate the redirection when required (to not pessimize code that would work with the IPTL generated by the iFUNC). ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 13:48 ` Adhemerval Zanella @ 2022-02-11 14:42 ` H.J. Lu 2022-02-11 14:56 ` Florian Weimer 0 siblings, 1 reply; 30+ messages in thread From: H.J. Lu @ 2022-02-11 14:42 UTC (permalink / raw) To: Adhemerval Zanella; +Cc: Szabolcs Nagy, Florian Weimer, GNU C Library On Fri, Feb 11, 2022 at 5:49 AM Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org> wrote: > > > > On 11/02/2022 10:24, Szabolcs Nagy wrote: > > The 02/11/2022 09:47, Adhemerval Zanella wrote: > >> On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: > >>> The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote > >>>> + dl_parse_auxv_t auxv_values = { 0, }; > >>>> + _dl_parse_auxv (av, auxv_values); > >>> > >>> this seems to use memset now on aarch64 before irelative > >>> relocs are resolved in static binaries. > >>> > >>> which causes infinite loops in the iplt (i've also seen > >>> segfaults in the build log). > >>> > >>> i wonder what is a clean fix... > >>> > >> > >> Maybe add inhibit_loop_to_libcall to avoid the memset call. > > > > does not work for me.. > > happens at -O0 too > > https://godbolt.org/z/W9r3nffYd > > Yeah, this won't help much this situation. Unless we can make gcc *not* > emit this memset call, we will need something like: > > diff --git a/elf/dl-support.c b/elf/dl-support.c > index 1977a2be76..49f3fd2a61 100644 > --- a/elf/dl-support.c > +++ b/elf/dl-support.c > @@ -19,6 +19,10 @@ > /* This file defines some things that for the dynamic linker are defined in > rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking. */ > > +#ifndef SHARED > +asm ("memset = __memset_generic"); > +#endif > + > #include <string.h> > /* Mark symbols hidden in static PIE for early self relocation to work. > Note: string.h may have ifuncs which cannot be hidden on i686. */ > > > $ make -j24 && make test t=elf/tst-tls1-static-non-pie > [...] > PASS: elf/tst-tls1-static-non-pie > original exit status 0 > set bar to 1 (LE) > get sum of foo and bar (IE) = 1 > get sum of foo and bar (LD or TLSDESC) = 1 > get sum of foo and bar (GD or TLSDESC) = 1 > > > I think the best approach would to add a __memset_generic, __memcpy_generic, > and __memmove_generic on all targets and add a header similar to > sysdeps/generic/symbol-hacks.h to activate the redirection when required > (to not pessimize code that would work with the IPTL generated by the > iFUNC). I ran into a similar problem on my CET branch. In my case, it is memcmp. I added a new header file, <dl-start.h>, to define functions which can be safely used during ld.so startup: https://gitlab.com/x86-glibc/glibc/-/commit/2bfa258b114e556ab0be68d6465b5e4fa5504e2e -- H.J. ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 14:42 ` H.J. Lu @ 2022-02-11 14:56 ` Florian Weimer 0 siblings, 0 replies; 30+ messages in thread From: Florian Weimer @ 2022-02-11 14:56 UTC (permalink / raw) To: H.J. Lu; +Cc: Adhemerval Zanella, Szabolcs Nagy, GNU C Library * H. J. Lu: > I ran into a similar problem on my CET branch. In my case, it is memcmp. > I added a new header file, <dl-start.h>, to define functions which can be safely > used during ld.so startup: > > https://gitlab.com/x86-glibc/glibc/-/commit/2bfa258b114e556ab0be68d6465b5e4fa5504e2e I think we would need something using assembler-level redirects because we need to change where the compiler-generated calls go. We probably need an adjustment to sysdeps/generic/symbol-hacks.h, and teach the stack protector controls to affect the symbol redirects (I think the requirements around TCB initialization are identical). Thanks, Florian ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 13:24 ` Szabolcs Nagy 2022-02-11 13:48 ` Adhemerval Zanella @ 2022-02-11 13:49 ` Florian Weimer 2022-02-11 14:17 ` Adhemerval Zanella 1 sibling, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-11 13:49 UTC (permalink / raw) To: Szabolcs Nagy; +Cc: Adhemerval Zanella, libc-alpha * Szabolcs Nagy: > The 02/11/2022 09:47, Adhemerval Zanella wrote: >> On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: >> > The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote >> >> + dl_parse_auxv_t auxv_values = { 0, }; >> >> + _dl_parse_auxv (av, auxv_values); >> > >> > this seems to use memset now on aarch64 before irelative >> > relocs are resolved in static binaries. >> > >> > which causes infinite loops in the iplt (i've also seen >> > segfaults in the build log). >> > >> > i wonder what is a clean fix... >> > >> >> Maybe add inhibit_loop_to_libcall to avoid the memset call. > > does not work for me.. > happens at -O0 too > https://godbolt.org/z/W9r3nffYd Seems to happen with -fno-builtin or -ffreestanding as well. It's a GCC bug, but I'll investigating working around it. Thanks, Florian ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 13:49 ` Florian Weimer @ 2022-02-11 14:17 ` Adhemerval Zanella 2022-02-11 14:29 ` Szabolcs Nagy 0 siblings, 1 reply; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-11 14:17 UTC (permalink / raw) To: Florian Weimer, Szabolcs Nagy; +Cc: libc-alpha On 11/02/2022 10:49, Florian Weimer wrote: > * Szabolcs Nagy: > >> The 02/11/2022 09:47, Adhemerval Zanella wrote: >>> On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: >>>> The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote >>>>> + dl_parse_auxv_t auxv_values = { 0, }; >>>>> + _dl_parse_auxv (av, auxv_values); >>>> >>>> this seems to use memset now on aarch64 before irelative >>>> relocs are resolved in static binaries. >>>> >>>> which causes infinite loops in the iplt (i've also seen >>>> segfaults in the build log). >>>> >>>> i wonder what is a clean fix... >>>> >>> >>> Maybe add inhibit_loop_to_libcall to avoid the memset call. >> >> does not work for me.. >> happens at -O0 too >> https://godbolt.org/z/W9r3nffYd > > Seems to happen with -fno-builtin or -ffreestanding as well. It's a GCC > bug, but I'll investigating working around it. I don't think it is gcc bug, even for -ffreestanding compiler can assume the C environment will always provide memset/memcpy. The problem is we need a gcc option to avoid such optimization, which afaik there is none. And without such option I think we will need to either revert this change or use the symbol alias strategy to avoid using IFUNC on loader code. ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 14:17 ` Adhemerval Zanella @ 2022-02-11 14:29 ` Szabolcs Nagy 2022-02-11 18:15 ` Adhemerval Zanella 0 siblings, 1 reply; 30+ messages in thread From: Szabolcs Nagy @ 2022-02-11 14:29 UTC (permalink / raw) To: Adhemerval Zanella; +Cc: Florian Weimer, libc-alpha The 02/11/2022 11:17, Adhemerval Zanella wrote: > On 11/02/2022 10:49, Florian Weimer wrote: > > * Szabolcs Nagy: > >> The 02/11/2022 09:47, Adhemerval Zanella wrote: > >>> On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: > >>>> The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote > >>>>> + dl_parse_auxv_t auxv_values = { 0, }; > >>>>> + _dl_parse_auxv (av, auxv_values); > >>>> > >>>> this seems to use memset now on aarch64 before irelative > >>>> relocs are resolved in static binaries. > >>>> > >>>> which causes infinite loops in the iplt (i've also seen > >>>> segfaults in the build log). > >>>> > >>>> i wonder what is a clean fix... > >>>> > >>> > >>> Maybe add inhibit_loop_to_libcall to avoid the memset call. > >> > >> does not work for me.. > >> happens at -O0 too > >> https://godbolt.org/z/W9r3nffYd > > > > Seems to happen with -fno-builtin or -ffreestanding as well. It's a GCC > > bug, but I'll investigating working around it. > > I don't think it is gcc bug, even for -ffreestanding compiler can assume > the C environment will always provide memset/memcpy. The problem is we > need a gcc option to avoid such optimization, which afaik there is none. > > And without such option I think we will need to either revert this change > or use the symbol alias strategy to avoid using IFUNC on loader code. if we can rewrite the code not to depend on zeroing a large array (where large is about >200bytes) that should work too. i dont see a clean way, but e.g. a char seen_auxval[AT_MINSIGSTKSZ+1] = {0}; would not trigger memset (on aarch64). as a bonus with such an array we can distinguish auxv unset and auxv 0. ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 14:29 ` Szabolcs Nagy @ 2022-02-11 18:15 ` Adhemerval Zanella 0 siblings, 0 replies; 30+ messages in thread From: Adhemerval Zanella @ 2022-02-11 18:15 UTC (permalink / raw) To: Szabolcs Nagy; +Cc: Florian Weimer, libc-alpha On 11/02/2022 11:29, Szabolcs Nagy wrote: > The 02/11/2022 11:17, Adhemerval Zanella wrote: >> On 11/02/2022 10:49, Florian Weimer wrote: >>> * Szabolcs Nagy: >>>> The 02/11/2022 09:47, Adhemerval Zanella wrote: >>>>> On 11/02/2022 09:31, Szabolcs Nagy via Libc-alpha wrote: >>>>>> The 02/03/2022 12:08, Florian Weimer via Libc-alpha wrote >>>>>>> + dl_parse_auxv_t auxv_values = { 0, }; >>>>>>> + _dl_parse_auxv (av, auxv_values); >>>>>> >>>>>> this seems to use memset now on aarch64 before irelative >>>>>> relocs are resolved in static binaries. >>>>>> >>>>>> which causes infinite loops in the iplt (i've also seen >>>>>> segfaults in the build log). >>>>>> >>>>>> i wonder what is a clean fix... >>>>>> >>>>> >>>>> Maybe add inhibit_loop_to_libcall to avoid the memset call. >>>> >>>> does not work for me.. >>>> happens at -O0 too >>>> https://godbolt.org/z/W9r3nffYd >>> >>> Seems to happen with -fno-builtin or -ffreestanding as well. It's a GCC >>> bug, but I'll investigating working around it. >> >> I don't think it is gcc bug, even for -ffreestanding compiler can assume >> the C environment will always provide memset/memcpy. The problem is we >> need a gcc option to avoid such optimization, which afaik there is none. >> >> And without such option I think we will need to either revert this change >> or use the symbol alias strategy to avoid using IFUNC on loader code. > > if we can rewrite the code not to depend on zeroing a large array > (where large is about >200bytes) that should work too. > > i dont see a clean way, but e.g. a > > char seen_auxval[AT_MINSIGSTKSZ+1] = {0}; > > would not trigger memset (on aarch64). > > as a bonus with such an array we can distinguish auxv unset and auxv 0. I think this kind of solution is fragile, if compiler decides to change the optimization threshold we will see a regression. ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 12:31 ` Szabolcs Nagy 2022-02-11 12:47 ` Adhemerval Zanella @ 2022-02-11 17:32 ` Florian Weimer 2022-02-11 17:49 ` Szabolcs Nagy 1 sibling, 1 reply; 30+ messages in thread From: Florian Weimer @ 2022-02-11 17:32 UTC (permalink / raw) To: Szabolcs Nagy; +Cc: libc-alpha * Szabolcs Nagy: > this seems to use memset now on aarch64 before irelative > relocs are resolved in static binaries. > > which causes infinite loops in the iplt (i've also seen > segfaults in the build log). > > i wonder what is a clean fix... I've reverted this for now. I missed the “static” part before; I think our build environment is not really set up for such redirects. Maybe the easiest/cleanest way for now is to use an explicit initialization loop for !SHARED, plus -fno-tree-loop-distribute-patterns. > char seen_auxval[AT_MINSIGSTKSZ+1] = {0}; > > would not trigger memset (on aarch64). > > as a bonus with such an array we can distinguish auxv unset and auxv 0. The current code does not need that because it writes the default values first: auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT; auxv_values[AT_PAGESZ] = EXEC_PAGESIZE; auxv_values[AT_FPUCW] = _FPU_DEFAULT; On the reader side, we would need to write if (seen_auxval[AT_CLKTCK]) GLRO(dl_clktck) = auxv_values[AT_CLKTCK]; and if (seen_auxval[AT_FPUCW]) auxv_values[AT_FPUCW] = auxv_values[AT_FPUCW]; else auxv_values[AT_FPUCW] = _FPU_DEFAULT; , which does not look like an improvement to me (neither maintenance-wise nor code-size-wise). Thanks, Florian ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing 2022-02-11 17:32 ` Florian Weimer @ 2022-02-11 17:49 ` Szabolcs Nagy 0 siblings, 0 replies; 30+ messages in thread From: Szabolcs Nagy @ 2022-02-11 17:49 UTC (permalink / raw) To: Florian Weimer; +Cc: libc-alpha The 02/11/2022 18:32, Florian Weimer wrote: > * Szabolcs Nagy: > > > this seems to use memset now on aarch64 before irelative > > relocs are resolved in static binaries. > > > > which causes infinite loops in the iplt (i've also seen > > segfaults in the build log). > > > > i wonder what is a clean fix... > > I've reverted this for now. I missed the “static” part before; I think > our build environment is not really set up for such redirects. Maybe > the easiest/cleanest way for now is to use an explicit initialization > loop for !SHARED, plus -fno-tree-loop-distribute-patterns. yeah, loop with __attribute__((optimize("no-tree-loop-distribute-patterns"))) on the function works. ^ permalink raw reply [flat|nested] 30+ messages in thread
end of thread, other threads:[~2022-02-11 18:15 UTC | newest] Thread overview: 30+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-02-03 11:08 [PATCH v2 0/5] Linux: Auxiliary vector parsing cleanups Florian Weimer 2022-02-03 11:08 ` [PATCH v2 1/5] elf: Merge dl-sysdep.c into the Linux version Florian Weimer 2022-02-08 20:09 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE Florian Weimer 2022-02-08 20:11 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 3/5] Linux: Remove DL_FIND_ARG_COMPONENTS Florian Weimer 2022-02-08 20:12 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 4/5] Linux: Assume that NEED_DL_SYSINFO_DSO is always defined Florian Weimer 2022-02-08 20:13 ` Adhemerval Zanella 2022-02-03 11:08 ` [PATCH v2 5/5] Linux: Consolidate auxiliary vector parsing Florian Weimer 2022-02-08 20:19 ` Adhemerval Zanella 2022-02-08 20:34 ` Florian Weimer 2022-02-08 22:57 ` Adhemerval Zanella 2022-02-10 10:54 ` Florian Weimer 2022-02-10 11:29 ` Adhemerval Zanella 2022-02-10 11:31 ` Florian Weimer 2022-02-10 11:40 ` Adhemerval Zanella 2022-02-10 11:46 ` Adhemerval Zanella 2022-02-11 12:31 ` Szabolcs Nagy 2022-02-11 12:47 ` Adhemerval Zanella 2022-02-11 13:24 ` Szabolcs Nagy 2022-02-11 13:48 ` Adhemerval Zanella 2022-02-11 14:42 ` H.J. Lu 2022-02-11 14:56 ` Florian Weimer 2022-02-11 13:49 ` Florian Weimer 2022-02-11 14:17 ` Adhemerval Zanella 2022-02-11 14:29 ` Szabolcs Nagy 2022-02-11 18:15 ` Adhemerval Zanella 2022-02-11 17:32 ` Florian Weimer 2022-02-11 17:49 ` Szabolcs Nagy
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).