mirror of
https://sourceware.org/git/glibc.git
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133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
/* Dynamic linker system dependencies for Linux.
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Copyright (C) 1995-2016 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, see
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<http://www.gnu.org/licenses/>. */
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/* Linux needs some special initialization, but otherwise uses
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the generic dynamic linker system interface code. */
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/param.h>
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#include <sys/utsname.h>
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#include <ldsodefs.h>
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#ifdef SHARED
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# define DL_SYSDEP_INIT frob_brk ()
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static inline void
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frob_brk (void)
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{
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__brk (0); /* Initialize the break. */
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}
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# include <elf/dl-sysdep.c>
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#endif
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int
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attribute_hidden
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_dl_discover_osversion (void)
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{
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#if 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(Nhdr) hdr;
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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 ElfW(Nhdr) *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 note->n_type - 1) & -sizeof note->n_type)
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note = ((const void *) (note + 1)
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+ ROUND (note->n_namesz) + ROUND (note->n_descsz));
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#undef ROUND
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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++ != '.' || parts == 3)
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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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