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From: Florian Weimer <fw@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] elf: Do not search HWCAP subdirectories in statically linked binaries Date: Wed, 7 Oct 2020 15:35:24 +0000 (GMT) [thread overview] Message-ID: <20201007153524.621A83857026@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=56f8d442942ee51824b4683be83f776a811a3f2a commit 56f8d442942ee51824b4683be83f776a811a3f2a Author: Florian Weimer <fweimer@redhat.com> Date: Wed Oct 7 16:40:23 2020 +0200 elf: Do not search HWCAP subdirectories in statically linked binaries This functionality does not seem to be useful since static dlopen is mostly used for iconv/character set conversion and NSS support. gconv modules are loaded with full paths anyway, so that the HWCAP subdirectory logic does not apply. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Diff: --- NEWS | 4 ++++ elf/Makefile | 4 ++-- elf/dl-load.c | 14 ++++++++++++++ 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/NEWS b/NEWS index 9a2fe0b17a..e84c39aeb1 100644 --- a/NEWS +++ b/NEWS @@ -33,6 +33,10 @@ Deprecated and removed features, and other changes affecting compatibility: * The mallinfo function is marked deprecated. Callers should call mallinfo2 instead. +* When dlopen is used in statically linked programs, alternative library + implementations from HWCAP subdirectories are no longer loaded. + Instead, the default implementation is used. + Changes to build and runtime requirements: * On Linux, the system administrator needs to configure /dev/pts with diff --git a/elf/Makefile b/elf/Makefile index c587e9f06e..e0a8bf2998 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -29,7 +29,7 @@ routines = $(all-dl-routines) dl-support dl-iteratephdr \ # The core dynamic linking functions are in libc for the static and # profiled libraries. -dl-routines = $(addprefix dl-,load lookup object reloc deps hwcaps \ +dl-routines = $(addprefix dl-,load lookup object reloc deps \ runtime init fini debug misc \ version profile tls origin scope \ execstack open close trampoline \ @@ -59,7 +59,7 @@ elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \ # ld.so uses those routines, plus some special stuff for being the program # interpreter and operating independent of libc. rtld-routines = rtld $(all-dl-routines) dl-sysdep dl-environ dl-minimal \ - dl-error-minimal dl-conflict + dl-error-minimal dl-conflict dl-hwcaps all-rtld-routines = $(rtld-routines) $(sysdep-rtld-routines) CFLAGS-dl-runtime.c += -fexceptions -fasynchronous-unwind-tables diff --git a/elf/dl-load.c b/elf/dl-load.c index 646c5dca40..5ba117d597 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -101,9 +101,13 @@ int __stack_prot attribute_hidden attribute_relro static struct r_search_path_struct env_path_list attribute_relro; /* List of the hardware capabilities we might end up using. */ +#ifdef SHARED static const struct r_strlenpair *capstr attribute_relro; static size_t ncapstr attribute_relro; static size_t max_capstrlen attribute_relro; +#else +enum { ncapstr = 1, max_capstrlen = 0 }; +#endif /* Get the generated information about the trusted directories. Use @@ -691,9 +695,11 @@ _dl_init_paths (const char *llp) /* Fill in the information about the application's RPATH and the directories addressed by the LD_LIBRARY_PATH environment variable. */ +#ifdef SHARED /* Get the capabilities. */ capstr = _dl_important_hwcaps (GLRO(dl_platform), GLRO(dl_platformlen), &ncapstr, &max_capstrlen); +#endif /* First set up the rest of the default search directory entries. */ aelem = rtld_search_dirs.dirs = (struct r_search_path_elem **) @@ -1521,11 +1527,15 @@ print_search_path (struct r_search_path_elem **list, for (cnt = 0; cnt < ncapstr; ++cnt) if ((*list)->status[cnt] != nonexisting) { +#ifdef SHARED char *cp = __mempcpy (endp, capstr[cnt].str, capstr[cnt].len); if (cp == buf || (cp == buf + 1 && buf[0] == '/')) cp[0] = '\0'; else cp[-1] = '\0'; +#else + *endp = '\0'; +#endif _dl_debug_printf_c (first ? "%s" : ":%s", buf); first = 0; @@ -1886,11 +1896,15 @@ open_path (const char *name, size_t namelen, int mode, if (this_dir->status[cnt] == nonexisting) continue; +#ifdef SHARED buflen = ((char *) __mempcpy (__mempcpy (edp, capstr[cnt].str, capstr[cnt].len), name, namelen) - buf); +#else + buflen = (char *) __mempcpy (edp, name, namelen) - buf; +#endif /* Print name we try if this is wanted. */ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
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