/* Support for dynamic linking code in static libc.
- Copyright (C) 1996-2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1996-2022 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
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. */
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
/* This file defines some things that for the dynamic linker are defined in
rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking. */
+#include <string.h>
+/* Mark symbols hidden in static PIE for early self relocation to work.
+ Note: string.h may have ifuncs which cannot be hidden on i686. */
+#if BUILD_PIE_DEFAULT
+# pragma GCC visibility push(hidden)
+#endif
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <unistd.h>
+#include <sys/param.h>
+#include <stdint.h>
#include <ldsodefs.h>
#include <dl-machine.h>
-#include <bits/libc-lock.h>
+#include <libc-lock.h>
#include <dl-cache.h>
#include <dl-librecon.h>
#include <dl-procinfo.h>
#include <unsecvars.h>
#include <hp-timing.h>
+#include <stackinfo.h>
+#include <dl-vdso.h>
+#include <dl-vdso-setup.h>
+#include <dl-auxv.h>
+#include <dl-find_object.h>
+#include <array_length.h>
extern char *__progname;
char **_dl_argv = &__progname; /* This is checked for some error messages. */
int _dl_debug_mask;
int _dl_lazy;
-ElfW(Addr) _dl_use_load_bias = -2;
int _dl_dynamic_weak;
/* If nonzero print warnings about problematic situations. */
/* Nonzero if runtime lookup should not update the .got/.plt. */
int _dl_bind_not;
+/* A dummy link map for the executable, used by dlopen to access the global
+ scope. We don't export any symbols ourselves, so this can be minimal. */
+static struct link_map _dl_main_map =
+ {
+ .l_name = (char *) "",
+ .l_real = &_dl_main_map,
+ .l_ns = LM_ID_BASE,
+ .l_libname = &(struct libname_list) { .name = "", .dont_free = 1 },
+ .l_searchlist =
+ {
+ .r_list = &(struct link_map *) { &_dl_main_map },
+ .r_nlist = 1,
+ },
+ .l_symbolic_searchlist = { .r_list = &(struct link_map *) { NULL } },
+ .l_type = lt_executable,
+ .l_scope_mem = { &_dl_main_map.l_searchlist },
+ .l_scope_max = (sizeof (_dl_main_map.l_scope_mem)
+ / sizeof (_dl_main_map.l_scope_mem[0])),
+ .l_scope = _dl_main_map.l_scope_mem,
+ .l_local_scope = { &_dl_main_map.l_searchlist },
+ .l_used = 1,
+ .l_tls_offset = NO_TLS_OFFSET,
+ .l_serial = 1,
+ };
+
/* Namespace information. */
-struct link_namespaces _dl_ns[DL_NNS];
+struct link_namespaces _dl_ns[DL_NNS] =
+ {
+ [LM_ID_BASE] =
+ {
+ ._ns_loaded = &_dl_main_map,
+ ._ns_nloaded = 1,
+ ._ns_main_searchlist = &_dl_main_map.l_searchlist,
+ }
+ };
+size_t _dl_nns = 1;
/* Incremented whenever something may have been added to dl_loaded. */
-unsigned long long _dl_load_adds;
+unsigned long long _dl_load_adds = 1;
-/* Fake scope. In dynamically linked binaries this is the scope of the
- main application but here we don't have something like this. So
- create a fake scope containing nothing. */
-struct r_scope_elem _dl_initial_searchlist;
+/* Fake scope of the main application. */
+struct r_scope_elem _dl_initial_searchlist =
+ {
+ .r_list = &(struct link_map *) { &_dl_main_map },
+ .r_nlist = 1,
+ };
#ifndef HAVE_INLINED_SYSCALLS
/* Nonzero during startup. */
int _dl_starting_up = 1;
#endif
+/* Random data provided by the kernel. */
+void *_dl_random;
+
/* Get architecture specific initializer. */
+#include <dl-procruntime.c>
#include <dl-procinfo.c>
-/* We expect less than a second for relocation. */
-#ifdef HP_SMALL_TIMING_AVAIL
-# undef HP_TIMING_AVAIL
-# define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
-#endif
-
-/* Initial value of the CPU clock. */
-#ifndef HP_TIMING_NONAVAIL
-hp_timing_t _dl_cpuclock_offset;
-#endif
+size_t _dl_pagesize = EXEC_PAGESIZE;
-void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls;
+size_t _dl_minsigstacksize = CONSTANT_MINSIGSTKSZ;
-size_t _dl_pagesize;
+int _dl_inhibit_cache;
unsigned int _dl_osversion;
int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID;
-ElfW(Phdr) *_dl_phdr;
+ElfW(auxv_t) *_dl_auxv;
+const ElfW(Phdr) *_dl_phdr;
size_t _dl_phnum;
-uint64_t _dl_hwcap __attribute__ ((nocommon));
-
-/* Prevailing state of the stack, PF_X indicating it's executable. */
-ElfW(Word) _dl_stack_flags = PF_R|PF_W|PF_X;
+uint64_t _dl_hwcap;
+uint64_t _dl_hwcap2;
+
+enum dso_sort_algorithm _dl_dso_sort_algo;
+
+/* The value of the FPU control word the kernel will preset in hardware. */
+fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
+
+#if !HAVE_TUNABLES
+/* This is not initialized to HWCAP_IMPORTANT, matching the definition
+ of _dl_important_hwcaps, below, where no hwcap strings are ever
+ used. This mask is still used to mediate the lookups in the cache
+ file. Since there is no way to set this nonzero (we don't grok the
+ LD_HWCAP_MASK environment variable here), there is no real point in
+ setting _dl_hwcap nonzero below, but we do anyway. */
+uint64_t _dl_hwcap_mask;
+#endif
+/* Prevailing state of the stack. Generally this includes PF_X, indicating it's
+ * executable but this isn't true for all platforms. */
+ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS;
+
+#if PTHREAD_IN_LIBC
+list_t _dl_stack_used;
+list_t _dl_stack_user;
+list_t _dl_stack_cache;
+size_t _dl_stack_cache_actsize;
+uintptr_t _dl_in_flight_stack;
+int _dl_stack_cache_lock;
+#else
/* If loading a shared object requires that we make the stack executable
when it was not, we do it by calling this function.
It returns an errno code or zero on success. */
-int (*_dl_make_stack_executable_hook) (void **) internal_function
- = _dl_make_stack_executable;
-
-
-/* Function in libpthread to wait for termination of lookups. */
-void (*_dl_wait_lookup_done) (void);
-
+int (*_dl_make_stack_executable_hook) (void **) = _dl_make_stack_executable;
+void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls;
+#endif
struct dl_scope_free_list *_dl_scope_free_list;
#ifdef NEED_DL_SYSINFO
-/* Needed for improved syscall handling on at least x86/Linux. */
-uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT;
+/* Needed for improved syscall handling on at least x86/Linux. NB: Don't
+ initialize it here to avoid RELATIVE relocation in static PIE. */
+uintptr_t _dl_sysinfo;
#endif
-#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
+#ifdef NEED_DL_SYSINFO_DSO
/* Address of the ELF headers in the vsyscall page. */
const ElfW(Ehdr) *_dl_sysinfo_dso;
+
+struct link_map *_dl_sysinfo_map;
+
+# include "get-dynamic-info.h"
#endif
+#include "setup-vdso.h"
+/* Define the vDSO function pointers. */
+#include <dl-vdso-setup.c>
/* During the program run we must not modify the global data of
loaded shared object simultanously in two threads. Therefore we
the loaded object might as well require a call to this function.
At this time it is not anymore a problem to modify the tables. */
__rtld_lock_define_initialized_recursive (, _dl_load_lock)
+/* This lock is used to keep __dl_iterate_phdr from inspecting the
+ list of loaded objects while an object is added to or removed from
+ that list. */
+__rtld_lock_define_initialized_recursive (, _dl_load_write_lock)
+ /* This lock protects global and module specific TLS related data.
+ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation),
+ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are
+ accessed and when TLS related relocations are processed for a
+ module. It was introduced to keep pthread_create accessing TLS
+ state that is being set up. */
+__rtld_lock_define_initialized_recursive (, _dl_load_tls_lock)
#ifdef HAVE_AUX_VECTOR
+#include <dl-parse_auxv.h>
+
int _dl_clktck;
void
-internal_function
_dl_aux_init (ElfW(auxv_t) *av)
{
- int seen = 0;
- uid_t uid = 0;
- gid_t gid = 0;
-
- for (; av->a_type != AT_NULL; ++av)
- switch (av->a_type)
- {
- case AT_PAGESZ:
- GLRO(dl_pagesize) = av->a_un.a_val;
- break;
- case AT_CLKTCK:
- GLRO(dl_clktck) = av->a_un.a_val;
- break;
- case AT_PHDR:
- GL(dl_phdr) = (void *) av->a_un.a_val;
- break;
- case AT_PHNUM:
- GL(dl_phnum) = av->a_un.a_val;
- break;
- case AT_HWCAP:
- GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
- break;
#ifdef NEED_DL_SYSINFO
- case AT_SYSINFO:
- GL(dl_sysinfo) = av->a_un.a_val;
- break;
-#endif
-#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
- case AT_SYSINFO_EHDR:
- GL(dl_sysinfo_dso) = (void *) av->a_un.a_val;
- break;
+ /* NB: Avoid RELATIVE relocation in static PIE. */
+ GL(dl_sysinfo) = DL_SYSINFO_DEFAULT;
#endif
- case AT_UID:
- uid ^= av->a_un.a_val;
- seen |= 1;
- break;
- case AT_EUID:
- uid ^= av->a_un.a_val;
- seen |= 2;
- break;
- case AT_GID:
- gid ^= av->a_un.a_val;
- seen |= 4;
- break;
- case AT_EGID:
- gid ^= av->a_un.a_val;
- seen |= 8;
- break;
- case AT_SECURE:
- seen = -1;
- __libc_enable_secure = av->a_un.a_val;
- __libc_enable_secure_decided = 1;
- break;
-# ifdef DL_PLATFORM_AUXV
- DL_PLATFORM_AUXV
-# endif
- }
- if (seen == 0xf)
- {
- __libc_enable_secure = uid != 0 || gid != 0;
- __libc_enable_secure_decided = 1;
- }
+
+ _dl_auxv = av;
+ dl_parse_auxv_t auxv_values;
+ /* Use an explicit initialization loop here because memset may not
+ be available yet. */
+ for (int i = 0; i < array_length (auxv_values); ++i)
+ auxv_values[i] = 0;
+ _dl_parse_auxv (av, auxv_values);
}
#endif
void
-internal_function
_dl_non_dynamic_init (void)
{
- if (HP_TIMING_AVAIL)
- HP_TIMING_NOW (_dl_cpuclock_offset);
-
- if (!_dl_pagesize)
- _dl_pagesize = __getpagesize ();
+ _dl_main_map.l_origin = _dl_get_origin ();
+ _dl_main_map.l_phdr = GL(dl_phdr);
+ _dl_main_map.l_phnum = GL(dl_phnum);
_dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
+ /* Set up the data structures for the system-supplied DSO early,
+ so they can influence _dl_init_paths. */
+ setup_vdso (NULL, NULL);
+
+ /* With vDSO setup we can initialize the function pointers. */
+ setup_vdso_pointers ();
+
/* Initialize the data structures for the search paths for shared
objects. */
- _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
+ _dl_init_paths (getenv ("LD_LIBRARY_PATH"), "LD_LIBRARY_PATH",
+ /* No glibc-hwcaps selection support in statically
+ linked binaries. */
+ NULL, NULL);
+
+ /* Remember the last search directory added at startup. */
+ _dl_init_all_dirs = GL(dl_all_dirs);
_dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
cp = (const char *) __rawmemchr (cp, '\0') + 1;
}
+#if !HAVE_TUNABLES
if (__access ("/etc/suid-debug", F_OK) != 0)
__unsetenv ("MALLOC_CHECK_");
+#endif
}
#ifdef DL_PLATFORM_INIT
if (_dl_platform != NULL)
_dl_platformlen = strlen (_dl_platform);
- /* Scan for a program header telling us the stack is nonexecutable. */
if (_dl_phdr != NULL)
- for (uint_fast16_t i = 0; i < _dl_phnum; ++i)
- if (_dl_phdr[i].p_type == PT_GNU_STACK)
+ for (const ElfW(Phdr) *ph = _dl_phdr; ph < &_dl_phdr[_dl_phnum]; ++ph)
+ switch (ph->p_type)
{
- _dl_stack_flags = _dl_phdr[i].p_flags;
+ /* Check if the stack is nonexecutable. */
+ case PT_GNU_STACK:
+ _dl_stack_flags = ph->p_flags;
break;
- }
-}
-
-const struct r_strlenpair *
-internal_function
-_dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
- size_t *max_capstrlen)
-{
- static struct r_strlenpair result;
- static char buf[1];
+ case PT_GNU_RELRO:
+ _dl_main_map.l_relro_addr = ph->p_vaddr;
+ _dl_main_map.l_relro_size = ph->p_memsz;
+ break;
+ }
- result.str = buf; /* Does not really matter. */
- result.len = 0;
+ call_function_static_weak (_dl_find_object_init);
- *sz = 1;
- return &result;
+ /* Setup relro on the binary itself. */
+ if (_dl_main_map.l_relro_size != 0)
+ _dl_protect_relro (&_dl_main_map);
}
-
#ifdef DL_SYSINFO_IMPLEMENTATION
DL_SYSINFO_IMPLEMENTATION
#endif
+
+#if ENABLE_STATIC_PIE
+/* Since relocation to hidden _dl_main_map causes relocation overflow on
+ aarch64, a function is used to get the address of _dl_main_map. */
+
+struct link_map *
+_dl_get_dl_main_map (void)
+{
+ return &_dl_main_map;
+}
+#endif
+
+/* This is used by _dl_runtime_profile, not used on static code. */
+void
+DL_ARCH_FIXUP_ATTRIBUTE
+_dl_audit_pltexit (struct link_map *l, ElfW(Word) reloc_arg,
+ const void *inregs, void *outregs)
+{
+}
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