253 lines
8.3 KiB
C
253 lines
8.3 KiB
C
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/* Dynamic linker system dependencies for Linux.
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Copyright (C) 1995-2022 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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<https://www.gnu.org/licenses/>. */
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#include <_itoa.h>
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#include <assert.h>
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#include <dl-auxv.h>
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#include <dl-osinfo.h>
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#include <dl-parse_auxv.h>
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#include <dl-procinfo.h>
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#include <dl-tunables.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 <ldsodefs.h>
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#include <libc-internal.h>
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#include <libintl.h>
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#include <not-cancel.h>
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#include <stdlib.h>
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#include <string.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/utsname.h>
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#include <tls.h>
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#include <unistd.h>
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#include <dl-machine.h>
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#include <dl-hwcap-check.h>
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#ifdef SHARED
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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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int __libc_enable_secure attribute_relro = 0;
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rtld_hidden_data_def (__libc_enable_secure)
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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_STACK_END
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# define DL_STACK_END(cookie) ((void *) (cookie))
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#endif
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/* Arguments passed to dl_main. */
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struct dl_main_arguments
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{
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const ElfW(Phdr) *phdr;
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ElfW(Word) phnum;
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ElfW(Addr) user_entry;
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};
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/* Separate function, so that dl_main can be called without the large
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array on the stack. */
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static void
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_dl_sysdep_parse_arguments (void **start_argptr,
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struct dl_main_arguments *args)
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{
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_dl_argc = (intptr_t) *start_argptr;
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_dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */
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_environ = _dl_argv + _dl_argc + 1;
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for (char **tmp = _environ; ; ++tmp)
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if (*tmp == NULL)
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{
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/* Another necessary aliasing violation. */
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GLRO(dl_auxv) = (ElfW(auxv_t) *) (tmp + 1);
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break;
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}
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dl_parse_auxv_t auxv_values = { 0, };
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_dl_parse_auxv (GLRO(dl_auxv), auxv_values);
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args->phdr = (const ElfW(Phdr) *) auxv_values[AT_PHDR];
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args->phnum = auxv_values[AT_PHNUM];
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args->user_entry = auxv_values[AT_ENTRY];
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}
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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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__libc_stack_end = DL_STACK_END (start_argptr);
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struct dl_main_arguments dl_main_args;
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_dl_sysdep_parse_arguments (start_argptr, &dl_main_args);
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dl_hwcap_check ();
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__tunables_init (_environ);
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/* Initialize DSO sorting algorithm after tunables. */
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_dl_sort_maps_init ();
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__brk (0); /* Initialize the break. */
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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 (__libc_enable_secure, 0))
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__libc_check_standard_fds ();
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(*dl_main) (dl_main_args.phdr, dl_main_args.phnum,
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&dl_main_args.user_entry, GLRO(dl_auxv));
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return dl_main_args.user_entry;
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}
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void
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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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_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[22];
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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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[AT_HWCAP2 - 2] = { "HWCAP2: 0x", hex },
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[AT_MINSIGSTKSZ - 2] = { "MINSIGSTKSZ: ", dec },
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[AT_L1I_CACHESIZE - 2] = { "L1I_CACHESIZE: ", dec },
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[AT_L1I_CACHEGEOMETRY - 2] = { "L1I_CACHEGEOMETRY: 0x", hex },
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[AT_L1D_CACHESIZE - 2] = { "L1D_CACHESIZE: ", dec },
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[AT_L1D_CACHEGEOMETRY - 2] = { "L1D_CACHEGEOMETRY: 0x", hex },
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[AT_L2_CACHESIZE - 2] = { "L2_CACHESIZE: ", dec },
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[AT_L2_CACHEGEOMETRY - 2] = { "L2_CACHEGEOMETRY: 0x", hex },
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[AT_L3_CACHESIZE - 2] = { "L3_CACHESIZE: ", dec },
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[AT_L3_CACHEGEOMETRY - 2] = { "L3_CACHEGEOMETRY: 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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/* Some entries are handled in a special way per platform. */
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if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
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continue;
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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 /* SHARED */
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