diff options
Diffstat (limited to 'libc/sysdeps/unix/sysv/linux/dl-osinfo.h')
| -rw-r--r-- | libc/sysdeps/unix/sysv/linux/dl-osinfo.h | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/libc/sysdeps/unix/sysv/linux/dl-osinfo.h b/libc/sysdeps/unix/sysv/linux/dl-osinfo.h new file mode 100644 index 000000000..0738501a5 --- /dev/null +++ b/libc/sysdeps/unix/sysv/linux/dl-osinfo.h @@ -0,0 +1,180 @@ +/* Operating system specific code for generic dynamic loader functions. Linux. + Copyright (C) 2000,2001,2002,2004,2005,2006 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <string.h> +#include <fcntl.h> +#include <sys/utsname.h> +#include <kernel-features.h> +#include <dl-sysdep.h> +#include <stdint.h> + +#ifndef MIN +# define MIN(a,b) (((a)<(b))?(a):(b)) +#endif + +#ifdef SHARED +/* This is the function used in the dynamic linker to print the fatal error + message. */ +static inline void +__attribute__ ((__noreturn__)) +dl_fatal (const char *str) +{ + _dl_dprintf (2, str); + _exit (1); +} +#endif + +static inline int __attribute__ ((always_inline)) +_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(Word) vendorlen; + ElfW(Word) datalen; + ElfW(Word) type; + 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 struct + { + ElfW(Word) vendorlen; + ElfW(Word) datalen; + ElfW(Word) type; + } *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 (ElfW(Word)) - 1) & -sizeof (ElfW(Word))) + note = ((const void *) (note + 1) + + ROUND (note->vendorlen) + ROUND (note->datalen)); + } + } + } +#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++ != '.') + /* Another part following? */ + break; + } + + if (parts < 3) + version <<= 8 * (3 - parts); + + return version; +} + +#define DL_SYSDEP_OSCHECK(FATAL) \ + do { \ + /* Test whether the kernel is new enough. This test is only performed \ + if the library is not compiled to run on all kernels. */ \ + \ + int version = _dl_discover_osversion (); \ + if (__builtin_expect (version >= 0, 1)) \ + { \ + if (__builtin_expect (GLRO(dl_osversion) == 0, 1) \ + || GLRO(dl_osversion) > version) \ + GLRO(dl_osversion) = version; \ + \ + /* Now we can test with the required version. */ \ + if (__LINUX_KERNEL_VERSION > 0 && version < __LINUX_KERNEL_VERSION) \ + /* Not sufficent. */ \ + FATAL ("FATAL: kernel too old\n"); \ + } \ + else if (__LINUX_KERNEL_VERSION > 0) \ + FATAL ("FATAL: cannot determine kernel version\n"); \ + } while (0) + +static inline uintptr_t __attribute__ ((always_inline)) +_dl_setup_stack_chk_guard (void) +{ + uintptr_t ret; +#ifdef ENABLE_STACKGUARD_RANDOMIZE + int fd = __open ("/dev/urandom", O_RDONLY); + if (fd >= 0) + { + ssize_t reslen = __read (fd, &ret, sizeof (ret)); + __close (fd); + if (reslen == (ssize_t) sizeof (ret)) + return ret; + } +#endif + ret = 0; + unsigned char *p = (unsigned char *) &ret; + p[sizeof (ret) - 1] = 255; + p[sizeof (ret) - 2] = '\n'; + return ret; +} |