diff options
Diffstat (limited to 'elf/dl-sysdep.c')
| -rw-r--r-- | elf/dl-sysdep.c | 602 |
1 files changed, 602 insertions, 0 deletions
diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c new file mode 100644 index 0000000000..68e08f480a --- /dev/null +++ b/elf/dl-sysdep.c @@ -0,0 +1,602 @@ +/* Operating system support for run-time dynamic linker. Generic Unix version. + Copyright (C) 1995-1998, 2000-2005, 2007 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 <assert.h> +#include <elf.h> +#include <errno.h> +#include <fcntl.h> +#include <libintl.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mman.h> +#include <ldsodefs.h> +#include <stdio-common/_itoa.h> +#include <fpu_control.h> + +#include <entry.h> +#include <dl-machine.h> +#include <dl-procinfo.h> +#include <dl-osinfo.h> +#include <hp-timing.h> +#include <tls.h> + +#ifdef _DL_FIRST_PLATFORM +# define _DL_FIRST_EXTRA (_DL_FIRST_PLATFORM + _DL_PLATFORMS_COUNT) +#else +# define _DL_FIRST_EXTRA _DL_HWCAP_COUNT +#endif + +extern char **_environ attribute_hidden; +extern void _end attribute_hidden; + +/* Protect SUID program against misuse of file descriptors. */ +extern void __libc_check_standard_fds (void); + +#ifdef NEED_DL_BASE_ADDR +ElfW(Addr) _dl_base_addr; +#endif +int __libc_enable_secure attribute_relro = 0; +INTVARDEF(__libc_enable_secure) +int __libc_multiple_libcs = 0; /* Defining this here avoids the inclusion + of init-first. */ +/* This variable contains the lowest stack address ever used. */ +void *__libc_stack_end attribute_relro = NULL; +rtld_hidden_data_def(__libc_stack_end) +static ElfW(auxv_t) *_dl_auxv attribute_relro; + +#ifndef DL_FIND_ARG_COMPONENTS +# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ + do { \ + void **_tmp; \ + (argc) = *(long int *) cookie; \ + (argv) = (char **) ((long int *) cookie + 1); \ + (envp) = (argv) + (argc) + 1; \ + for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ + continue; \ + (auxp) = (void *) ++_tmp; \ + } while (0) +#endif + +#ifndef DL_STACK_END +# define DL_STACK_END(cookie) ((void *) (cookie)) +#endif + +ElfW(Addr) +_dl_sysdep_start (void **start_argptr, + void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, + ElfW(Addr) *user_entry)) +{ + const ElfW(Phdr) *phdr = NULL; + ElfW(Word) phnum = 0; + ElfW(Addr) user_entry; + ElfW(auxv_t) *av; +#ifdef HAVE_AUX_SECURE +# define set_seen(tag) (tag) /* Evaluate for the side effects. */ +# define set_seen_secure() ((void) 0) +#else + uid_t uid = 0; + gid_t gid = 0; + unsigned int seen = 0; +# define set_seen_secure() (seen = -1) +# ifdef HAVE_AUX_XID +# define set_seen(tag) (tag) /* Evaluate for the side effects. */ +# else +# define M(type) (1 << (type)) +# define set_seen(tag) seen |= M ((tag)->a_type) +# endif +#endif +#ifdef NEED_DL_SYSINFO + uintptr_t new_sysinfo = 0; +#endif + + __libc_stack_end = DL_STACK_END (start_argptr); + DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, INTUSE(_dl_argv), _environ, + _dl_auxv); + + user_entry = (ElfW(Addr)) ENTRY_POINT; + GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ + + for (av = _dl_auxv; av->a_type != AT_NULL; set_seen (av++)) + switch (av->a_type) + { + case AT_PHDR: + phdr = (void *) av->a_un.a_val; + break; + case AT_PHNUM: + phnum = av->a_un.a_val; + break; + case AT_PAGESZ: + GLRO(dl_pagesize) = av->a_un.a_val; + break; + case AT_ENTRY: + user_entry = av->a_un.a_val; + break; +#ifdef NEED_DL_BASE_ADDR + case AT_BASE: + _dl_base_addr = av->a_un.a_val; + break; +#endif +#ifndef HAVE_AUX_SECURE + case AT_UID: + case AT_EUID: + uid ^= av->a_un.a_val; + break; + case AT_GID: + case AT_EGID: + gid ^= av->a_un.a_val; + break; +#endif + case AT_SECURE: +#ifndef HAVE_AUX_SECURE + seen = -1; +#endif + INTUSE(__libc_enable_secure) = av->a_un.a_val; + break; + case AT_PLATFORM: + GLRO(dl_platform) = (void *) av->a_un.a_val; + break; + case AT_HWCAP: + GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; + break; + case AT_CLKTCK: + GLRO(dl_clktck) = av->a_un.a_val; + break; + case AT_FPUCW: + GLRO(dl_fpu_control) = av->a_un.a_val; + break; +#ifdef NEED_DL_SYSINFO + case AT_SYSINFO: + new_sysinfo = av->a_un.a_val; + break; +#endif +#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO + case AT_SYSINFO_EHDR: + GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; + break; +#endif +#ifdef DL_PLATFORM_AUXV + DL_PLATFORM_AUXV +#endif + } + +#ifndef HAVE_AUX_SECURE + if (seen != -1) + { + /* Fill in the values we have not gotten from the kernel through the + auxiliary vector. */ +# ifndef HAVE_AUX_XID +# define SEE(UID, var, uid) \ + if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () + SEE (UID, uid, uid); + SEE (EUID, uid, euid); + SEE (GID, gid, gid); + SEE (EGID, gid, egid); +# endif + + /* If one of the two pairs of IDs does not match this is a setuid + or setgid run. */ + INTUSE(__libc_enable_secure) = uid | gid; + } +#endif + +#ifndef HAVE_AUX_PAGESIZE + if (GLRO(dl_pagesize) == 0) + GLRO(dl_pagesize) = __getpagesize (); +#endif + +#if defined NEED_DL_SYSINFO + /* Only set the sysinfo value if we also have the vsyscall DSO. */ + if (GLRO(dl_sysinfo_dso) != 0 && new_sysinfo) + GLRO(dl_sysinfo) = new_sysinfo; +#endif + +#ifdef DL_SYSDEP_INIT + DL_SYSDEP_INIT; +#endif + +#ifdef DL_PLATFORM_INIT + DL_PLATFORM_INIT; +#endif + + /* Determine the length of the platform name. */ + if (GLRO(dl_platform) != NULL) + GLRO(dl_platformlen) = strlen (GLRO(dl_platform)); + + if (__sbrk (0) == &_end) + /* The dynamic linker was run as a program, and so the initial break + starts just after our bss, at &_end. The malloc in dl-minimal.c + will consume the rest of this page, so tell the kernel to move the + break up that far. When the user program examines its break, it + will see this new value and not clobber our data. */ + __sbrk (GLRO(dl_pagesize) + - ((&_end - (void *) 0) & (GLRO(dl_pagesize) - 1))); + + /* If this is a SUID program we make sure that FDs 0, 1, and 2 are + allocated. If necessary we are doing it ourself. If it is not + possible we stop the program. */ + if (__builtin_expect (INTUSE(__libc_enable_secure), 0)) + __libc_check_standard_fds (); + + (*dl_main) (phdr, phnum, &user_entry); + return user_entry; +} + +void +internal_function +_dl_sysdep_start_cleanup (void) +{ +} + +void +internal_function +_dl_show_auxv (void) +{ + char buf[64]; + ElfW(auxv_t) *av; + + /* Terminate string. */ + buf[63] = '\0'; + + /* The following code assumes that the AT_* values are encoded + starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values + close by (otherwise the array will be too large). In case we have + to support a platform where these requirements are not fulfilled + some alternative implementation has to be used. */ + for (av = _dl_auxv; av->a_type != AT_NULL; ++av) + { + static const struct + { + const char label[20]; + enum { unknown = 0, dec, hex, str, ignore } form; + } auxvars[] = + { + [AT_EXECFD - 2] = { "AT_EXECFD: ", dec }, + [AT_PHDR - 2] = { "AT_PHDR: 0x", hex }, + [AT_PHENT - 2] = { "AT_PHENT: ", dec }, + [AT_PHNUM - 2] = { "AT_PHNUM: ", dec }, + [AT_PAGESZ - 2] = { "AT_PAGESZ: ", dec }, + [AT_BASE - 2] = { "AT_BASE: 0x", hex }, + [AT_FLAGS - 2] = { "AT_FLAGS: 0x", hex }, + [AT_ENTRY - 2] = { "AT_ENTRY: 0x", hex }, + [AT_NOTELF - 2] = { "AT_NOTELF: ", hex }, + [AT_UID - 2] = { "AT_UID: ", dec }, + [AT_EUID - 2] = { "AT_EUID: ", dec }, + [AT_GID - 2] = { "AT_GID: ", dec }, + [AT_EGID - 2] = { "AT_EGID: ", dec }, + [AT_PLATFORM - 2] = { "AT_PLATFORM: ", str }, + [AT_HWCAP - 2] = { "AT_HWCAP: ", hex }, + [AT_CLKTCK - 2] = { "AT_CLKTCK: ", dec }, + [AT_FPUCW - 2] = { "AT_FPUCW: ", hex }, + [AT_DCACHEBSIZE - 2] = { "AT_DCACHEBSIZE: 0x", hex }, + [AT_ICACHEBSIZE - 2] = { "AT_ICACHEBSIZE: 0x", hex }, + [AT_UCACHEBSIZE - 2] = { "AT_UCACHEBSIZE: 0x", hex }, + [AT_IGNOREPPC - 2] = { "AT_IGNOREPPC", ignore }, + [AT_SECURE - 2] = { "AT_SECURE: ", dec }, + [AT_SYSINFO - 2] = { "AT_SYSINFO: 0x", hex }, + [AT_SYSINFO_EHDR - 2] = { "AT_SYSINFO_EHDR: 0x", hex }, + }; + unsigned int idx = (unsigned int) (av->a_type - 2); + + if ((unsigned int) av->a_type < 2u || auxvars[idx].form == ignore) + continue; + + assert (AT_NULL == 0); + assert (AT_IGNORE == 1); + + if (av->a_type == AT_HWCAP) + { + /* This is handled special. */ + if (_dl_procinfo (av->a_un.a_val) == 0) + continue; + } + + if (idx < sizeof (auxvars) / sizeof (auxvars[0]) + && auxvars[idx].form != unknown) + { + const char *val = (char *) av->a_un.a_val; + + if (__builtin_expect (auxvars[idx].form, dec) == dec) + val = _itoa ((unsigned long int) av->a_un.a_val, + buf + sizeof buf - 1, 10, 0); + else if (__builtin_expect (auxvars[idx].form, hex) == hex) + val = _itoa ((unsigned long int) av->a_un.a_val, + buf + sizeof buf - 1, 16, 0); + + _dl_printf ("%s%s\n", auxvars[idx].label, val); + + continue; + } + + /* Unknown value: print a generic line. */ + char buf2[17]; + buf[sizeof (buf2) - 1] = '\0'; + const char *val2 = _itoa ((unsigned long int) av->a_un.a_val, + buf2 + sizeof buf2 - 1, 16, 0); + const char *val = _itoa ((unsigned long int) av->a_type, + buf + sizeof buf - 1, 16, 0); + _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2); + } +} + + +/* Return an array of useful/necessary hardware capability names. */ +const struct r_strlenpair * +internal_function +_dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz, + size_t *max_capstrlen) +{ + /* Determine how many important bits are set. */ + uint64_t masked = GLRO(dl_hwcap) & GLRO(dl_hwcap_mask); + size_t cnt = platform != NULL; + size_t n, m; + size_t total; + struct r_strlenpair *temp; + struct r_strlenpair *result; + struct r_strlenpair *rp; + char *cp; + + /* Count the number of bits set in the masked value. */ + for (n = 0; (~((1ULL << n) - 1) & masked) != 0; ++n) + if ((masked & (1ULL << n)) != 0) + ++cnt; + +#if (defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO) && defined SHARED + /* The system-supplied DSO can contain a note of type 2, vendor "GNU". + This gives us a list of names to treat as fake hwcap bits. */ + + const char *dsocaps = NULL; + size_t dsocapslen = 0; + if (GLRO(dl_sysinfo_map) != NULL) + { + 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) + { +#define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word))) + if (note->type == 2 + && note->vendorlen == sizeof "GNU" + && !memcmp ((note + 1), "GNU", sizeof "GNU") + && note->datalen > 2 * sizeof (ElfW(Word)) + 2) + { + const ElfW(Word) *p = ((const void *) (note + 1) + + ROUND (sizeof "GNU")); + cnt += *p++; + ++p; /* Skip mask word. */ + dsocaps = (const char *) p; + dsocapslen = note->datalen - sizeof *p * 2; + break; + } + note = ((const void *) (note + 1) + + ROUND (note->vendorlen) + ROUND (note->datalen)); + } + if (dsocaps != NULL) + break; + } + } +#endif + +#ifdef USE_TLS + /* For TLS enabled builds always add 'tls'. */ + ++cnt; +#else + if (cnt == 0) + { + /* If we no have platform name and no important capability we only + have the base directory to search. */ + result = (struct r_strlenpair *) malloc (sizeof (*result)); + if (result == NULL) + goto no_memory; + + result[0].str = (char *) result; /* Does not really matter. */ + result[0].len = 0; + + *sz = 1; + return result; + } +#endif + + /* Create temporary data structure to generate result table. */ + temp = (struct r_strlenpair *) alloca (cnt * sizeof (*temp)); + m = 0; +#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO + if (dsocaps != NULL) + { + const ElfW(Word) mask = ((const ElfW(Word) *) dsocaps)[-1]; + GLRO(dl_hwcap) |= (uint64_t) mask << _DL_FIRST_EXTRA; + size_t len; + for (const char *p = dsocaps; p < dsocaps + dsocapslen; p += len + 1) + { + uint_fast8_t bit = *p++; + len = strlen (p); + + /* Skip entries that are not enabled in the mask word. */ + if (__builtin_expect (mask & ((ElfW(Word)) 1 << bit), 1)) + { + temp[m].str = p; + temp[m].len = len; + ++m; + } + else + --cnt; + } + } +#endif + for (n = 0; masked != 0; ++n) + if ((masked & (1ULL << n)) != 0) + { + temp[m].str = _dl_hwcap_string (n); + temp[m].len = strlen (temp[m].str); + masked ^= 1ULL << n; + ++m; + } + if (platform != NULL) + { + temp[m].str = platform; + temp[m].len = platform_len; + ++m; + } +#ifdef USE_TLS + temp[m].str = "tls"; + temp[m].len = 3; + ++m; +#endif + assert (m == cnt); + + /* Determine the total size of all strings together. */ + if (cnt == 1) + total = temp[0].len + 1; + else + { + total = temp[0].len + temp[cnt - 1].len + 2; + if (cnt > 2) + { + total <<= 1; + for (n = 1; n + 1 < cnt; ++n) + total += temp[n].len + 1; + if (cnt > 3 + && (cnt >= sizeof (size_t) * 8 + || total + (sizeof (*result) << 3) + >= (1UL << (sizeof (size_t) * 8 - cnt + 3)))) + _dl_signal_error (ENOMEM, NULL, NULL, + N_("cannot create capability list")); + + total <<= cnt - 3; + } + } + + /* The result structure: we use a very compressed way to store the + various combinations of capability names. */ + *sz = 1 << cnt; + result = (struct r_strlenpair *) malloc (*sz * sizeof (*result) + total); + if (result == NULL) + { +#ifndef USE_TLS + no_memory: +#endif + _dl_signal_error (ENOMEM, NULL, NULL, + N_("cannot create capability list")); + } + + if (cnt == 1) + { + result[0].str = (char *) (result + *sz); + result[0].len = temp[0].len + 1; + result[1].str = (char *) (result + *sz); + result[1].len = 0; + cp = __mempcpy ((char *) (result + *sz), temp[0].str, temp[0].len); + *cp = '/'; + *sz = 2; + *max_capstrlen = result[0].len; + + return result; + } + + /* Fill in the information. This follows the following scheme + (indeces from TEMP for four strings): + entry #0: 0, 1, 2, 3 binary: 1111 + #1: 0, 1, 3 1101 + #2: 0, 2, 3 1011 + #3: 0, 3 1001 + This allows the representation of all possible combinations of + capability names in the string. First generate the strings. */ + result[1].str = result[0].str = cp = (char *) (result + *sz); +#define add(idx) \ + cp = __mempcpy (__mempcpy (cp, temp[idx].str, temp[idx].len), "/", 1); + if (cnt == 2) + { + add (1); + add (0); + } + else + { + n = 1 << (cnt - 1); + do + { + n -= 2; + + /* We always add the last string. */ + add (cnt - 1); + + /* Add the strings which have the bit set in N. */ + for (m = cnt - 2; m > 0; --m) + if ((n & (1 << m)) != 0) + add (m); + + /* Always add the first string. */ + add (0); + } + while (n != 0); + } +#undef add + + /* Now we are ready to install the string pointers and length. */ + for (n = 0; n < (1UL << cnt); ++n) + result[n].len = 0; + n = cnt; + do + { + size_t mask = 1 << --n; + + rp = result; + for (m = 1 << cnt; m > 0; ++rp) + if ((--m & mask) != 0) + rp->len += temp[n].len + 1; + } + while (n != 0); + + /* The first half of the strings all include the first string. */ + n = (1 << cnt) - 2; + rp = &result[2]; + while (n != (1UL << (cnt - 1))) + { + if ((--n & 1) != 0) + rp[0].str = rp[-2].str + rp[-2].len; + else + rp[0].str = rp[-1].str; + ++rp; + } + + /* The second half starts right after the first part of the string of + the corresponding entry in the first half. */ + do + { + rp[0].str = rp[-(1 << (cnt - 1))].str + temp[cnt - 1].len + 1; + ++rp; + } + while (--n != 0); + + /* The maximum string length. */ + *max_capstrlen = result[0].len; + + return result; +} |