/* Minimal replacements for basic facilities used in the dynamic linker.
- Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
+ Copyright (C) 1995-2023 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 Library General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ 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
- Library General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If not,
- write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <unistd.h>
#include <assert.h>
-#include <string.h>
-#include <link.h>
-#include <stdio-common/_itoa.h>
+#include <ldsodefs.h>
+#include <dl-irel.h>
+#include <dl-hash.h>
+#include <dl-sym-post.h>
+#include <_itoa.h>
+#include <dl-minimal-malloc.h>
+#include <stdio.h>
+#include <unistd.h>
#include <errno.h>
-/* Minimal `malloc' allocator for use while loading shared libraries.
- No block is ever freed. */
+/* The rtld startup code calls __rtld_malloc_init_stubs after the
+ first self-relocation to adjust the pointers to the minimal
+ implementation below. Before the final relocation,
+ __rtld_malloc_init_real is called to replace the pointers with the
+ real implementation. */
+__typeof (calloc) *__rtld_calloc attribute_relro;
+__typeof (free) *__rtld_free attribute_relro;
+__typeof (malloc) *__rtld_malloc attribute_relro;
+__typeof (realloc) *__rtld_realloc attribute_relro;
-static void *alloc_ptr, *alloc_end, *alloc_last_block;
+void
+__rtld_malloc_init_stubs (void)
+{
+ __rtld_calloc = &__minimal_calloc;
+ __rtld_free = &__minimal_free;
+ __rtld_malloc = &__minimal_malloc;
+ __rtld_realloc = &__minimal_realloc;
+}
-void * weak_function
-malloc (size_t n)
+bool
+__rtld_malloc_is_complete (void)
{
-#ifdef MAP_ANON
-#define _dl_zerofd (-1)
-#else
- extern int _dl_zerofd;
-
- if (_dl_zerofd == -1)
- _dl_zerofd = _dl_sysdep_open_zero_fill ();
-#define MAP_ANON 0
-#endif
+ /* The caller assumes that there is an active malloc. */
+ assert (__rtld_malloc != NULL);
+ return __rtld_malloc != &__minimal_malloc;
+}
- if (alloc_end == 0)
- {
- /* Consume any unused space in the last page of our data segment. */
- extern int _end;
- alloc_ptr = &_end;
- alloc_end = (void *) 0 + (((alloc_ptr - (void *) 0) + _dl_pagesize - 1)
- & ~(_dl_pagesize - 1));
- }
+/* Lookup NAME at VERSION in the scope of MATCH. */
+static void *
+lookup_malloc_symbol (struct link_map *main_map, const char *name,
+ struct r_found_version *version)
+{
- /* Make sure the allocation pointer is ideally aligned. */
- alloc_ptr = (void *) 0 + (((alloc_ptr - (void *) 0) + sizeof (double) - 1)
- & ~(sizeof (double) - 1));
+ const ElfW(Sym) *ref = NULL;
+ lookup_t result = _dl_lookup_symbol_x (name, main_map, &ref,
+ main_map->l_scope,
+ version, 0, 0, NULL);
- if (alloc_ptr + n >= alloc_end)
- {
- /* Insufficient space left; allocate another page. */
- caddr_t page;
- size_t nup = (n + _dl_pagesize - 1) & ~(_dl_pagesize - 1);
- page = __mmap (0, nup, PROT_READ|PROT_WRITE,
- MAP_ANON|MAP_PRIVATE, _dl_zerofd, 0);
- assert (page != MAP_FAILED);
- if (page != alloc_end)
- alloc_ptr = page;
- alloc_end = page + nup;
- }
+ assert (ELFW(ST_TYPE) (ref->st_info) != STT_TLS);
+ void *value = DL_SYMBOL_ADDRESS (result, ref);
- alloc_last_block = (void *) alloc_ptr;
- alloc_ptr += n;
- return alloc_last_block;
+ return _dl_sym_post (result, ref, value, 0, main_map);
}
-/* We use this function occasionally since the real implementation may
- be optimized when it can assume the memory it returns already is
- set to NUL. */
-void * weak_function
-calloc (size_t nmemb, size_t size)
+void
+__rtld_malloc_init_real (struct link_map *main_map)
{
- size_t total = nmemb * size;
- void *result = malloc (total);
- return memset (result, '\0', total);
-}
+ /* We cannot use relocations and initializers for this because the
+ changes made by __rtld_malloc_init_stubs break REL-style
+ (non-RELA) relocations that depend on the previous pointer
+ contents. Also avoid direct relocation dependencies for the
+ malloc symbols so this function can be called before the final
+ rtld relocation (which enables RELRO, after which the pointer
+ variables cannot be written to). */
-/* This will rarely be called. */
-void weak_function
-free (void *ptr)
-{
- /* We can free only the last block allocated. */
- if (ptr == alloc_last_block)
- alloc_ptr = alloc_last_block;
-}
+ struct r_found_version version;
+ version.name = symbol_version_string (libc, GLIBC_2_0);
+ version.hidden = 0;
+ version.hash = _dl_elf_hash (version.name);
+ version.filename = NULL;
-/* This is only called with the most recent block returned by malloc. */
-void * weak_function
-realloc (void *ptr, size_t n)
-{
- void *new;
- assert (ptr == alloc_last_block);
- alloc_ptr = alloc_last_block;
- new = malloc (n);
- assert (new == ptr);
- return new;
+ void *new_calloc = lookup_malloc_symbol (main_map, "calloc", &version);
+ void *new_free = lookup_malloc_symbol (main_map, "free", &version);
+ void *new_malloc = lookup_malloc_symbol (main_map, "malloc", &version);
+ void *new_realloc = lookup_malloc_symbol (main_map, "realloc", &version);
+
+ /* Update the pointers in one go, so that any internal allocations
+ performed by lookup_malloc_symbol see a consistent
+ implementation. */
+ __rtld_calloc = new_calloc;
+ __rtld_free = new_free;
+ __rtld_malloc = new_malloc;
+ __rtld_realloc = new_realloc;
}
+
\f
/* Avoid signal frobnication in setjmp/longjmp. Keeps things smaller. */
#include <setjmp.h>
int weak_function
-__sigjmp_save (sigjmp_buf env, int savemask)
+__sigjmp_save (sigjmp_buf env, int savemask __attribute__ ((unused)))
{
- env[0].__mask_was_saved = savemask;
+ env[0].__mask_was_saved = 0;
return 0;
}
-
-void weak_function
-longjmp (jmp_buf env, int val)
-{
- __longjmp (env[0].__jmpbuf, val);
-}
\f
/* Define our own version of the internal function used by strerror. We
only provide the messages for some common errors. This avoids pulling
in the whole error list. */
char * weak_function
-_strerror_internal (int errnum, char *buf, size_t buflen)
+__strerror_r (int errnum, char *buf, size_t buflen)
{
char *msg;
/* No need to check buffer size, all calls in the dynamic linker
provide enough space. */
buf[buflen - 1] = '\0';
- msg = _itoa_word (errnum, buf + buflen - 1, 10, 0);
+ msg = _itoa (errnum, buf + buflen - 1, 10, 0);
msg = memcpy (msg - (sizeof ("Error ") - 1), "Error ",
sizeof ("Error ") - 1);
break;
return msg;
}
\f
-#ifndef NDEBUG
+void
+__libc_fatal (const char *message)
+{
+ _dl_fatal_printf ("%s", message);
+}
+rtld_hidden_def (__libc_fatal)
+void
+__attribute__ ((noreturn))
+__chk_fail (void)
+{
+ _exit (127);
+}
+rtld_hidden_def (__chk_fail)
+
+#ifndef NDEBUG
/* Define (weakly) our own assert failure function which doesn't use stdio.
If we are linked into the user program (-ldl), the normal __assert_fail
defn can override this one. */
__assert_fail (const char *assertion,
const char *file, unsigned int line, const char *function)
{
- char buf[64];
- buf[sizeof buf - 1] = '\0';
- _dl_sysdep_fatal ("BUG IN DYNAMIC LINKER ld.so: ",
- file, ": ", _itoa_word (line, buf + sizeof buf - 1, 10, 0),
- ": ", function ?: "", function ? ": " : "",
- "Assertion `", assertion, "' failed!\n",
- NULL);
+ _dl_fatal_printf ("\
+Inconsistency detected by ld.so: %s: %u: %s%sAssertion `%s' failed!\n",
+ file, line, function ?: "", function ? ": " : "",
+ assertion);
}
+# ifndef NO_RTLD_HIDDEN
+rtld_hidden_weak (__assert_fail)
+# endif
void weak_function
__assert_perror_fail (int errnum,
const char *file, unsigned int line,
const char *function)
{
- char buf[64];
- buf[sizeof buf - 1] = '\0';
- _dl_sysdep_fatal ("BUG IN DYNAMIC LINKER ld.so: ",
- file, ": ", _itoa_word (line, buf + sizeof buf - 1, 10, 0),
- ": ", function ?: "", function ? ": " : "",
- "Unexpected error: ", strerror (errnum), "\n", NULL);
+ char errbuf[400];
+ _dl_fatal_printf ("\
+Inconsistency detected by ld.so: %s: %u: %s%sUnexpected error: %s.\n",
+ file, line, function ?: "", function ? ": " : "",
+ __strerror_r (errnum, errbuf, sizeof errbuf));
}
-
+# ifndef NO_RTLD_HIDDEN
+rtld_hidden_weak (__assert_perror_fail)
+# endif
#endif
+\f
+#undef _itoa
+/* We always use _itoa instead of _itoa_word in ld.so since the former
+ also has to be present and it is never about speed when these
+ functions are used. */
+char *
+_itoa (unsigned long long int value, char *buflim, unsigned int base,
+ int upper_case)
+{
+ assert (! upper_case);
+
+ do
+ *--buflim = _itoa_lower_digits[value % base];
+ while ((value /= base) != 0);
+
+ return buflim;
+}
+
+/* The '_itoa_lower_digits' variable in libc.so is able to handle bases
+ up to 36. We don't need this here. */
+const char _itoa_lower_digits[16] = "0123456789abcdef";
+rtld_hidden_data_def (_itoa_lower_digits)
+\f
+/* The following is not a complete strsep implementation. It cannot
+ handle empty delimiter strings. But this isn't necessary for the
+ execution of ld.so. */
+#undef strsep
+#undef __strsep
+char *
+__strsep (char **stringp, const char *delim)
+{
+ char *begin;
+
+ assert (delim[0] != '\0');
+
+ begin = *stringp;
+ if (begin != NULL)
+ {
+ char *end = begin;
+
+ while (*end != '\0' || (end = NULL))
+ {
+ const char *dp = delim;
+
+ do
+ if (*dp == *end)
+ break;
+ while (*++dp != '\0');
+
+ if (*dp != '\0')
+ {
+ *end++ = '\0';
+ break;
+ }
+
+ ++end;
+ }
+
+ *stringp = end;
+ }
+
+ return begin;
+}
+weak_alias (__strsep, strsep)
+strong_alias (__strsep, __strsep_g)
projects / thirdparty / glibc.git / blobdiff