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From: H.J. Lu <hjl@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] elf: Add <dl-r_debug.h> Date: Mon, 31 Jan 2022 15:52:30 +0000 (GMT) [thread overview] Message-ID: <20220131155230.2B765389C41B@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=3fb18fd80c5900cc82748f3320b30516c57d24da commit 3fb18fd80c5900cc82748f3320b30516c57d24da Author: H.J. Lu <hjl.tools@gmail.com> Date: Sat Jan 29 10:56:45 2022 -0800 elf: Add <dl-r_debug.h> Add <dl-r_debug.h> to get the adddress of the r_debug structure after relocation and its offset before relocation from the PT_DYNAMIC segment to support DT_DEBUG, DT_MIPS_RLD_MAP_REL and DT_MIPS_RLD_MAP. Co-developed-by: Xi Ruoyao <xry111@mengyan1223.wang> Diff: --- elf/pldd-xx.c | 34 +++++++++++++---------- elf/tst-dlmopen4.c | 15 +++-------- sysdeps/generic/dl-r_debug.h | 36 +++++++++++++++++++++++++ sysdeps/mips/dl-r_debug.h | 64 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 124 insertions(+), 25 deletions(-) diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c index 1cdfb49c53..30513b423f 100644 --- a/elf/pldd-xx.c +++ b/elf/pldd-xx.c @@ -22,6 +22,8 @@ #define EW_(e, w, t) EW__(e, w, _##t) #define EW__(e, w, t) e##w##t +#include <dl-r_debug.h> + struct E(link_map) { EW(Addr) l_addr; @@ -126,21 +128,25 @@ E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv, != p[i].p_filesz) error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section")); - /* Search for the DT_DEBUG entry. */ + /* Search for the struct r_debug. */ for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j) - if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0) - { - struct E(r_debug) r; - if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr) - != sizeof (r)) - error (EXIT_FAILURE, 0, gettext ("cannot read r_debug")); - - if (r.r_map != 0) - { - list = r.r_map; - break; - } - } + { + EW(Addr) off = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j; + off = E(r_debug_offset) (&dyn[j], memfd, off); + if (off != 0) + { + struct E(r_debug) r; + if (pread (memfd, &r, sizeof (r), off) + != sizeof (r)) + error (EXIT_FAILURE, 0, gettext ("cannot read r_debug")); + + if (r.r_map != 0) + { + list = r.r_map; + break; + } + } + } free (dyn); break; diff --git a/elf/tst-dlmopen4.c b/elf/tst-dlmopen4.c index d8bcf7e9d5..8456f89053 100644 --- a/elf/tst-dlmopen4.c +++ b/elf/tst-dlmopen4.c @@ -25,16 +25,9 @@ #include <support/check.h> #include <support/test-driver.h> -#ifndef ELF_MACHINE_GET_R_DEBUG -# define ELF_MACHINE_GET_R_DEBUG(d) \ - (__extension__ ({ \ - struct r_debug_extended *debug; \ - if ((d)->d_tag == DT_DEBUG) \ - debug = (struct r_debug_extended *) (d)->d_un.d_ptr; \ - else \ - debug = NULL; \ - debug; })) -#endif +#define E(x) x +#define EW(x) ElfW(x) +#include <dl-r_debug.h> static int do_test (void) @@ -44,7 +37,7 @@ do_test (void) for (d = _DYNAMIC; d->d_tag != DT_NULL; ++d) { - debug = ELF_MACHINE_GET_R_DEBUG (d); + debug = (struct r_debug_extended *) r_debug_address (d); if (debug != NULL) break; } diff --git a/sysdeps/generic/dl-r_debug.h b/sysdeps/generic/dl-r_debug.h new file mode 100644 index 0000000000..e3edeb4f06 --- /dev/null +++ b/sysdeps/generic/dl-r_debug.h @@ -0,0 +1,36 @@ +/* Function to access r_debug structure. Generic version. + Copyright (C) 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/>. */ + +/* Return the address of the struct r_debug after relocation. */ + +static inline EW(Addr) +E(r_debug_address) (EW(Dyn) *d) +{ + if (d->d_tag == DT_DEBUG) + return (EW(Addr)) d->d_un.d_ptr; + + return 0; +} + +/* Return the offset of the struct r_debug before relocation. */ + +static inline EW(Addr) +E(r_debug_offset) (EW(Dyn) *d, int fd, EW(Addr) offset) +{ + return E(r_debug_address) (d); +} diff --git a/sysdeps/mips/dl-r_debug.h b/sysdeps/mips/dl-r_debug.h new file mode 100644 index 0000000000..edd83d46fd --- /dev/null +++ b/sysdeps/mips/dl-r_debug.h @@ -0,0 +1,64 @@ +/* Function to access r_debug structure. MIPS specific version. + Copyright (C) 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/>. */ + +#ifdef EW_ +/* Return the offset of the struct r_debug before relocation. */ + +static inline EW(Addr) +E(r_debug_offset) (EW(Dyn) *d, int fd, EW(Addr) offset) +{ + switch (d->d_tag) + { + case DT_MIPS_RLD_MAP_REL: + offset += d->d_un.d_val; + break; + case DT_MIPS_RLD_MAP: + offset = d->d_un.d_ptr; + break; + default: + return 0; + } + + if (pread (fd, &offset, sizeof (offset), offset) != sizeof (offset)) + return 0; + + return offset; +} +#else +/* Return the address of the struct r_debug after relocation. */ + +static inline EW(Addr) +E(r_debug_address) (EW(Dyn) *d) +{ + EW(Addr) ptr; + + switch (d->d_tag) + { + case DT_MIPS_RLD_MAP_REL: + ptr = ((EW(Addr)) d) + d->d_un.d_val; + break; + case DT_MIPS_RLD_MAP: + ptr = d->d_un.d_ptr; + break; + default: + return 0; + } + + return *(EW(Addr) *) ptr; +} +#endif
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