348 lines
10 KiB
C
348 lines
10 KiB
C
/* Operating system support for run-time dynamic linker. Generic Unix version.
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Copyright (C) 1995-2012 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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/* We conditionalize the whole of this file rather than simply eliding it
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from the static build, because other sysdeps/ versions of this file
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might define things needed by a static build. */
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#ifdef SHARED
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#include <assert.h>
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#include <elf.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <libintl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <ldsodefs.h>
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#include <_itoa.h>
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#include <fpu_control.h>
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#include <entry.h>
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#include <dl-machine.h>
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#include <dl-procinfo.h>
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#include <dl-osinfo.h>
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#include <hp-timing.h>
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#include <tls.h>
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extern char **_environ attribute_hidden;
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extern char _end[] attribute_hidden;
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/* Protect SUID program against misuse of file descriptors. */
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extern void __libc_check_standard_fds (void);
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#ifdef NEED_DL_BASE_ADDR
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ElfW(Addr) _dl_base_addr;
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#endif
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int __libc_enable_secure attribute_relro = 0;
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INTVARDEF(__libc_enable_secure)
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int __libc_multiple_libcs = 0; /* Defining this here avoids the inclusion
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of init-first. */
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/* This variable contains the lowest stack address ever used. */
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void *__libc_stack_end attribute_relro = NULL;
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rtld_hidden_data_def(__libc_stack_end)
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void *_dl_random attribute_relro = NULL;
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#ifndef DL_FIND_ARG_COMPONENTS
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# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \
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do { \
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void **_tmp; \
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(argc) = *(long int *) cookie; \
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(argv) = (char **) ((long int *) cookie + 1); \
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(envp) = (argv) + (argc) + 1; \
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for (_tmp = (void **) (envp); *_tmp; ++_tmp) \
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continue; \
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(auxp) = (void *) ++_tmp; \
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} while (0)
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#endif
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#ifndef DL_STACK_END
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# define DL_STACK_END(cookie) ((void *) (cookie))
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#endif
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ElfW(Addr)
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_dl_sysdep_start (void **start_argptr,
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void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
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ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
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{
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const ElfW(Phdr) *phdr = NULL;
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ElfW(Word) phnum = 0;
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ElfW(Addr) user_entry;
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ElfW(auxv_t) *av;
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#ifdef HAVE_AUX_SECURE
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# define set_seen(tag) (tag) /* Evaluate for the side effects. */
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# define set_seen_secure() ((void) 0)
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#else
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uid_t uid = 0;
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gid_t gid = 0;
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unsigned int seen = 0;
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# define set_seen_secure() (seen = -1)
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# ifdef HAVE_AUX_XID
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# define set_seen(tag) (tag) /* Evaluate for the side effects. */
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# else
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# define M(type) (1 << (type))
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# define set_seen(tag) seen |= M ((tag)->a_type)
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# endif
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#endif
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#ifdef NEED_DL_SYSINFO
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uintptr_t new_sysinfo = 0;
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#endif
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__libc_stack_end = DL_STACK_END (start_argptr);
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DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, INTUSE(_dl_argv), _environ,
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GLRO(dl_auxv));
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user_entry = (ElfW(Addr)) ENTRY_POINT;
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GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */
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for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++))
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switch (av->a_type)
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{
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case AT_PHDR:
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phdr = (void *) av->a_un.a_val;
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break;
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case AT_PHNUM:
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phnum = av->a_un.a_val;
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break;
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case AT_PAGESZ:
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GLRO(dl_pagesize) = av->a_un.a_val;
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break;
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case AT_ENTRY:
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user_entry = av->a_un.a_val;
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break;
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#ifdef NEED_DL_BASE_ADDR
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case AT_BASE:
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_dl_base_addr = av->a_un.a_val;
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break;
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#endif
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#ifndef HAVE_AUX_SECURE
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case AT_UID:
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case AT_EUID:
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uid ^= av->a_un.a_val;
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break;
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case AT_GID:
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case AT_EGID:
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gid ^= av->a_un.a_val;
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break;
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#endif
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case AT_SECURE:
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#ifndef HAVE_AUX_SECURE
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seen = -1;
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#endif
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INTUSE(__libc_enable_secure) = av->a_un.a_val;
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break;
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case AT_PLATFORM:
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GLRO(dl_platform) = (void *) av->a_un.a_val;
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break;
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case AT_HWCAP:
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GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
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break;
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case AT_CLKTCK:
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GLRO(dl_clktck) = av->a_un.a_val;
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break;
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case AT_FPUCW:
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GLRO(dl_fpu_control) = av->a_un.a_val;
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break;
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#ifdef NEED_DL_SYSINFO
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case AT_SYSINFO:
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new_sysinfo = av->a_un.a_val;
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break;
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#endif
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#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
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case AT_SYSINFO_EHDR:
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GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
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break;
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#endif
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case AT_RANDOM:
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_dl_random = (void *) av->a_un.a_val;
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break;
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#ifdef DL_PLATFORM_AUXV
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DL_PLATFORM_AUXV
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#endif
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}
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#ifndef HAVE_AUX_SECURE
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if (seen != -1)
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{
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/* Fill in the values we have not gotten from the kernel through the
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auxiliary vector. */
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# ifndef HAVE_AUX_XID
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# define SEE(UID, var, uid) \
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if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
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SEE (UID, uid, uid);
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SEE (EUID, uid, euid);
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SEE (GID, gid, gid);
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SEE (EGID, gid, egid);
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# endif
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/* If one of the two pairs of IDs does not match this is a setuid
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or setgid run. */
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INTUSE(__libc_enable_secure) = uid | gid;
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}
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#endif
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#ifndef HAVE_AUX_PAGESIZE
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if (GLRO(dl_pagesize) == 0)
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GLRO(dl_pagesize) = __getpagesize ();
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#endif
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#if defined NEED_DL_SYSINFO
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/* Only set the sysinfo value if we also have the vsyscall DSO. */
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if (GLRO(dl_sysinfo_dso) != 0 && new_sysinfo)
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GLRO(dl_sysinfo) = new_sysinfo;
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#endif
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#ifdef DL_SYSDEP_INIT
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DL_SYSDEP_INIT;
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#endif
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#ifdef DL_PLATFORM_INIT
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DL_PLATFORM_INIT;
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#endif
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/* Determine the length of the platform name. */
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if (GLRO(dl_platform) != NULL)
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GLRO(dl_platformlen) = strlen (GLRO(dl_platform));
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if (__sbrk (0) == _end)
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/* The dynamic linker was run as a program, and so the initial break
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starts just after our bss, at &_end. The malloc in dl-minimal.c
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will consume the rest of this page, so tell the kernel to move the
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break up that far. When the user program examines its break, it
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will see this new value and not clobber our data. */
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__sbrk (GLRO(dl_pagesize)
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- ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1)));
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/* If this is a SUID program we make sure that FDs 0, 1, and 2 are
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allocated. If necessary we are doing it ourself. If it is not
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possible we stop the program. */
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if (__builtin_expect (INTUSE(__libc_enable_secure), 0))
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__libc_check_standard_fds ();
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(*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
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return user_entry;
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}
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void
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internal_function
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_dl_sysdep_start_cleanup (void)
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{
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}
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void
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internal_function
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_dl_show_auxv (void)
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{
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char buf[64];
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ElfW(auxv_t) *av;
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/* Terminate string. */
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buf[63] = '\0';
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/* The following code assumes that the AT_* values are encoded
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starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
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close by (otherwise the array will be too large). In case we have
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to support a platform where these requirements are not fulfilled
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some alternative implementation has to be used. */
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for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av)
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{
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static const struct
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{
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const char label[17];
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enum { unknown = 0, dec, hex, str, ignore } form : 8;
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} auxvars[] =
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{
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[AT_EXECFD - 2] = { "EXECFD: ", dec },
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[AT_EXECFN - 2] = { "EXECFN: ", str },
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[AT_PHDR - 2] = { "PHDR: 0x", hex },
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[AT_PHENT - 2] = { "PHENT: ", dec },
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[AT_PHNUM - 2] = { "PHNUM: ", dec },
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[AT_PAGESZ - 2] = { "PAGESZ: ", dec },
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[AT_BASE - 2] = { "BASE: 0x", hex },
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[AT_FLAGS - 2] = { "FLAGS: 0x", hex },
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[AT_ENTRY - 2] = { "ENTRY: 0x", hex },
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[AT_NOTELF - 2] = { "NOTELF: ", hex },
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[AT_UID - 2] = { "UID: ", dec },
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[AT_EUID - 2] = { "EUID: ", dec },
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[AT_GID - 2] = { "GID: ", dec },
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[AT_EGID - 2] = { "EGID: ", dec },
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[AT_PLATFORM - 2] = { "PLATFORM: ", str },
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[AT_HWCAP - 2] = { "HWCAP: ", hex },
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[AT_CLKTCK - 2] = { "CLKTCK: ", dec },
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[AT_FPUCW - 2] = { "FPUCW: ", hex },
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[AT_DCACHEBSIZE - 2] = { "DCACHEBSIZE: 0x", hex },
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[AT_ICACHEBSIZE - 2] = { "ICACHEBSIZE: 0x", hex },
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[AT_UCACHEBSIZE - 2] = { "UCACHEBSIZE: 0x", hex },
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[AT_IGNOREPPC - 2] = { "IGNOREPPC", ignore },
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[AT_SECURE - 2] = { "SECURE: ", dec },
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[AT_BASE_PLATFORM - 2] = { "BASE_PLATFORM:", str },
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[AT_SYSINFO - 2] = { "SYSINFO: 0x", hex },
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[AT_SYSINFO_EHDR - 2] = { "SYSINFO_EHDR: 0x", hex },
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[AT_RANDOM - 2] = { "RANDOM: 0x", hex },
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};
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unsigned int idx = (unsigned int) (av->a_type - 2);
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if ((unsigned int) av->a_type < 2u
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|| (idx < sizeof (auxvars) / sizeof (auxvars[0])
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&& auxvars[idx].form == ignore))
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continue;
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assert (AT_NULL == 0);
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assert (AT_IGNORE == 1);
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if (av->a_type == AT_HWCAP)
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{
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/* This is handled special. */
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if (_dl_procinfo (av->a_un.a_val) == 0)
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continue;
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}
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if (idx < sizeof (auxvars) / sizeof (auxvars[0])
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&& auxvars[idx].form != unknown)
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{
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const char *val = (char *) av->a_un.a_val;
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if (__builtin_expect (auxvars[idx].form, dec) == dec)
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val = _itoa ((unsigned long int) av->a_un.a_val,
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buf + sizeof buf - 1, 10, 0);
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else if (__builtin_expect (auxvars[idx].form, hex) == hex)
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val = _itoa ((unsigned long int) av->a_un.a_val,
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buf + sizeof buf - 1, 16, 0);
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_dl_printf ("AT_%s%s\n", auxvars[idx].label, val);
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continue;
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}
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/* Unknown value: print a generic line. */
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char buf2[17];
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buf2[sizeof (buf2) - 1] = '\0';
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const char *val2 = _itoa ((unsigned long int) av->a_un.a_val,
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buf2 + sizeof buf2 - 1, 16, 0);
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const char *val = _itoa ((unsigned long int) av->a_type,
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buf + sizeof buf - 1, 16, 0);
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_dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2);
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}
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}
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#endif
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