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181 lines
5.2 KiB
C
181 lines
5.2 KiB
C
/* Operating system specific code for generic dynamic loader functions. Linux.
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Copyright (C) 2000,2001,2002,2004,2005,2006 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <string.h>
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#include <fcntl.h>
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#include <sys/utsname.h>
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#include <kernel-features.h>
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#include <dl-sysdep.h>
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#include <stdint.h>
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#ifndef MIN
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# define MIN(a,b) (((a)<(b))?(a):(b))
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#endif
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#ifdef SHARED
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/* This is the function used in the dynamic linker to print the fatal error
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message. */
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static inline void
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__attribute__ ((__noreturn__))
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dl_fatal (const char *str)
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{
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_dl_dprintf (2, str);
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_exit (1);
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}
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#endif
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static inline int __attribute__ ((always_inline))
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_dl_discover_osversion (void)
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{
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#if (defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO) && defined SHARED
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if (GLRO(dl_sysinfo_map) != NULL)
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{
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/* If the kernel-supplied DSO contains a note indicating the kernel's
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version, we don't need to call uname or parse any strings. */
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static const struct
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{
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ElfW(Word) vendorlen;
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ElfW(Word) datalen;
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ElfW(Word) type;
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char vendor[8];
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} expected_note = { sizeof "Linux", sizeof (ElfW(Word)), 0, "Linux" };
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const ElfW(Phdr) *const phdr = GLRO(dl_sysinfo_map)->l_phdr;
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const ElfW(Word) phnum = GLRO(dl_sysinfo_map)->l_phnum;
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for (uint_fast16_t i = 0; i < phnum; ++i)
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if (phdr[i].p_type == PT_NOTE)
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{
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const ElfW(Addr) start = (phdr[i].p_vaddr
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+ GLRO(dl_sysinfo_map)->l_addr);
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const struct
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{
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ElfW(Word) vendorlen;
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ElfW(Word) datalen;
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ElfW(Word) type;
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} *note = (const void *) start;
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while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz)
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{
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if (!memcmp (note, &expected_note, sizeof expected_note))
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return *(const ElfW(Word) *) ((const void *) note
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+ sizeof expected_note);
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#define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word)))
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note = ((const void *) (note + 1)
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+ ROUND (note->vendorlen) + ROUND (note->datalen));
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}
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}
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}
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#endif
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char bufmem[64];
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char *buf = bufmem;
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unsigned int version;
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int parts;
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char *cp;
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struct utsname uts;
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/* Try the uname system call. */
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if (__uname (&uts))
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{
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/* This was not successful. Now try reading the /proc filesystem. */
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int fd = __open ("/proc/sys/kernel/osrelease", O_RDONLY);
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if (fd < 0)
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return -1;
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ssize_t reslen = __read (fd, bufmem, sizeof (bufmem));
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__close (fd);
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if (reslen <= 0)
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/* This also didn't work. We give up since we cannot
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make sure the library can actually work. */
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return -1;
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buf[MIN (reslen, (ssize_t) sizeof (bufmem) - 1)] = '\0';
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}
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else
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buf = uts.release;
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/* Now convert it into a number. The string consists of at most
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three parts. */
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version = 0;
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parts = 0;
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cp = buf;
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while ((*cp >= '0') && (*cp <= '9'))
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{
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unsigned int here = *cp++ - '0';
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while ((*cp >= '0') && (*cp <= '9'))
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{
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here *= 10;
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here += *cp++ - '0';
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}
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++parts;
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version <<= 8;
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version |= here;
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if (*cp++ != '.')
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/* Another part following? */
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break;
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}
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if (parts < 3)
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version <<= 8 * (3 - parts);
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return version;
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}
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#define DL_SYSDEP_OSCHECK(FATAL) \
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do { \
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/* Test whether the kernel is new enough. This test is only performed \
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if the library is not compiled to run on all kernels. */ \
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\
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int version = _dl_discover_osversion (); \
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if (__builtin_expect (version >= 0, 1)) \
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{ \
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if (__builtin_expect (GLRO(dl_osversion) == 0, 1) \
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|| GLRO(dl_osversion) > version) \
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GLRO(dl_osversion) = version; \
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\
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/* Now we can test with the required version. */ \
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if (__LINUX_KERNEL_VERSION > 0 && version < __LINUX_KERNEL_VERSION) \
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/* Not sufficent. */ \
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FATAL ("FATAL: kernel too old\n"); \
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} \
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else if (__LINUX_KERNEL_VERSION > 0) \
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FATAL ("FATAL: cannot determine kernel version\n"); \
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} while (0)
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static inline uintptr_t __attribute__ ((always_inline))
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_dl_setup_stack_chk_guard (void)
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{
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uintptr_t ret;
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#ifdef ENABLE_STACKGUARD_RANDOMIZE
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int fd = __open ("/dev/urandom", O_RDONLY);
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if (fd >= 0)
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{
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ssize_t reslen = __read (fd, &ret, sizeof (ret));
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__close (fd);
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if (reslen == (ssize_t) sizeof (ret))
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return ret;
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}
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#endif
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ret = 0;
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unsigned char *p = (unsigned char *) &ret;
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p[sizeof (ret) - 1] = 255;
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p[sizeof (ret) - 2] = '\n';
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return ret;
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}
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