diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/dl-sysdep.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-sysdep.c | 98 |
1 files changed, 97 insertions, 1 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c index 42aec77e82..d4be205cde 100644 --- a/sysdeps/unix/sysv/linux/dl-sysdep.c +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c @@ -1,5 +1,5 @@ /* Dynamic linker system dependencies for Linux. - Copyright (C) 1995,1997,2001,2004,2005,2006 Free Software Foundation, Inc. + Copyright (C) 1995,1997,2001,2004,2005,2006, 2008 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 @@ -20,7 +20,10 @@ /* Linux needs some special initialization, but otherwise uses the generic dynamic linker system interface code. */ +#include <string.h> +#include <fcntl.h> #include <unistd.h> +#include <sys/utsname.h> #include <ldsodefs.h> #include <kernel-features.h> @@ -54,3 +57,96 @@ frob_brk (void) } #include <elf/dl-sysdep.c> + + +int +attribute_hidden +_dl_discover_osversion (void) +{ +#if (defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO) && defined SHARED + if (GLRO(dl_sysinfo_map) != NULL) + { + /* If the kernel-supplied DSO contains a note indicating the kernel's + version, we don't need to call uname or parse any strings. */ + + static const struct + { + ElfW(Nhdr) hdr; + char vendor[8]; + } expected_note = { { sizeof "Linux", sizeof (ElfW(Word)), 0 }, "Linux" }; + const ElfW(Phdr) *const phdr = GLRO(dl_sysinfo_map)->l_phdr; + const ElfW(Word) phnum = GLRO(dl_sysinfo_map)->l_phnum; + for (uint_fast16_t i = 0; i < phnum; ++i) + if (phdr[i].p_type == PT_NOTE) + { + const ElfW(Addr) start = (phdr[i].p_vaddr + + GLRO(dl_sysinfo_map)->l_addr); + const ElfW(Nhdr) *note = (const void *) start; + while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz) + { + if (!memcmp (note, &expected_note, sizeof expected_note)) + return *(const ElfW(Word) *) ((const void *) note + + sizeof expected_note); +#define ROUND(len) (((len) + sizeof note->n_type - 1) & -sizeof note->n_type) + note = ((const void *) (note + 1) + + ROUND (note->n_namesz) + ROUND (note->n_descsz)); +#undef ROUND + } + } + } +#endif + + char bufmem[64]; + char *buf = bufmem; + unsigned int version; + int parts; + char *cp; + struct utsname uts; + + /* Try the uname system call. */ + if (__uname (&uts)) + { + /* This was not successful. Now try reading the /proc filesystem. */ + int fd = __open ("/proc/sys/kernel/osrelease", O_RDONLY); + if (fd < 0) + return -1; + ssize_t reslen = __read (fd, bufmem, sizeof (bufmem)); + __close (fd); + if (reslen <= 0) + /* This also didn't work. We give up since we cannot + make sure the library can actually work. */ + return -1; + buf[MIN (reslen, (ssize_t) sizeof (bufmem) - 1)] = '\0'; + } + else + buf = uts.release; + + /* Now convert it into a number. The string consists of at most + three parts. */ + version = 0; + parts = 0; + cp = buf; + while ((*cp >= '0') && (*cp <= '9')) + { + unsigned int here = *cp++ - '0'; + + while ((*cp >= '0') && (*cp <= '9')) + { + here *= 10; + here += *cp++ - '0'; + } + + ++parts; + version <<= 8; + version |= here; + + if (*cp++ != '.' || parts == 3) + /* Another part following? */ + break; + } + + if (parts < 3) + version <<= 8 * (3 - parts); + + return version; +} |