/* Minimal replacements for basic facilities used in the dynamic linker.
- Copyright (C) 1995,96,97,98,2000,2001,2002 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
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 <errno.h>
-#include <limits.h>
-#include <string.h>
-#include <tls.h>
-#include <unistd.h>
-#include <sys/mman.h>
-#include <sys/param.h>
-#include <sys/types.h>
-#include <ldsodefs.h>
-#include <stdio-common/_itoa.h>
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
#include <assert.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. */
-
-static void *alloc_ptr, *alloc_end, *alloc_last_block;
-
-/* Declarations of global functions. */
-extern void weak_function free (void *ptr);
-extern void * weak_function realloc (void *ptr, size_t n);
-extern unsigned long int weak_function __strtoul_internal (const char *nptr,
- char **endptr,
- int base,
- int group);
-extern unsigned long int weak_function strtoul (const char *nptr,
- char **endptr, int base);
-
-
-void * weak_function
-malloc (size_t n)
+/* 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;
+
+void
+__rtld_malloc_init_stubs (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
-
- if (alloc_end == 0)
- {
- /* Consume any unused space in the last page of our data segment. */
- extern int _end attribute_hidden;
- alloc_ptr = &_end;
- alloc_end = (void *) 0 + (((alloc_ptr - (void *) 0)
- + GL(dl_pagesize) - 1)
- & ~(GL(dl_pagesize) - 1));
- }
-
- /* Make sure the allocation pointer is ideally aligned. */
- alloc_ptr = (void *) 0 + (((alloc_ptr - (void *) 0) + sizeof (double) - 1)
- & ~(sizeof (double) - 1));
-
- if (alloc_ptr + n >= alloc_end)
- {
- /* Insufficient space left; allocate another page. */
- caddr_t page;
- size_t nup = (n + GL(dl_pagesize) - 1) & ~(GL(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;
- }
-
- alloc_last_block = (void *) alloc_ptr;
- alloc_ptr += n;
- return alloc_last_block;
+ __rtld_calloc = &__minimal_calloc;
+ __rtld_free = &__minimal_free;
+ __rtld_malloc = &__minimal_malloc;
+ __rtld_realloc = &__minimal_realloc;
}
-/* 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)
+bool
+__rtld_malloc_is_complete (void)
{
- size_t total = nmemb * size;
- void *result = malloc (total);
- return memset (result, '\0', total);
+ /* The caller assumes that there is an active malloc. */
+ assert (__rtld_malloc != NULL);
+ return __rtld_malloc != &__minimal_malloc;
}
-/* This will rarely be called. */
-void weak_function
-free (void *ptr)
+/* 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)
{
- /* We can free only the last block allocated. */
- if (ptr == alloc_last_block)
- alloc_ptr = alloc_last_block;
-}
-/* This is only called with the most recent block returned by malloc. */
-void * weak_function
-realloc (void *ptr, size_t n)
-{
- void *new;
- if (ptr == NULL)
- return malloc (n);
- assert (ptr == alloc_last_block);
- alloc_ptr = alloc_last_block;
- new = malloc (n);
- assert (new == ptr);
- return new;
+ const ElfW(Sym) *ref = NULL;
+ lookup_t result = _dl_lookup_symbol_x (name, main_map, &ref,
+ main_map->l_scope,
+ version, 0, 0, NULL);
+
+ assert (ELFW(ST_TYPE) (ref->st_info) != STT_TLS);
+ void *value = DL_SYMBOL_ADDRESS (result, ref);
+
+ return _dl_sym_post (result, ref, value, 0, main_map);
}
-/* Return alligned memory block. */
-void * weak_function
-__libc_memalign (size_t align, size_t n)
+void
+__rtld_malloc_init_real (struct link_map *main_map)
{
- void *newp = malloc (n + align - 1);
-
- return (void *) roundup ((uintptr_t) newp, align);
+ /* 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). */
+
+ 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;
+
+ 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. */
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
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. */
assertion);
}
-INTDEF(__assert_fail)
-
-#endif
+# ifndef NO_RTLD_HIDDEN
+rtld_hidden_weak (__assert_fail)
+# endif
-unsigned long int weak_function
-__strtoul_internal (const char *nptr, char **endptr, int base, int group)
+void weak_function
+__assert_perror_fail (int errnum,
+ const char *file, unsigned int line,
+ const char *function)
{
- unsigned long int result = 0;
- long int sign = 1;
-
- while (*nptr == ' ' || *nptr == '\t')
- ++nptr;
-
- if (*nptr == '-')
- {
- sign = -1;
- ++nptr;
- }
- else if (*nptr == '+')
- ++nptr;
-
- if (*nptr < '0' || *nptr > '9')
- {
- if (endptr != NULL)
- *endptr = (char *) nptr;
- return 0UL;
- }
-
- assert (base == 0);
- base = 10;
- if (*nptr == '0')
- {
- if (nptr[1] == 'x' || nptr[1] == 'X')
- {
- base = 16;
- nptr += 2;
- }
- else
- base = 8;
- }
-
- while (*nptr >= '0' && *nptr <= '9')
- {
- unsigned long int digval = *nptr - '0';
- if (result > LONG_MAX / 10
- || (result == ULONG_MAX / 10 && digval > ULONG_MAX % 10))
- {
- errno = ERANGE;
- if (endptr != NULL)
- *endptr = (char *) nptr;
- return ULONG_MAX;
- }
- result *= base;
- result += digval;
- ++nptr;
- }
+ 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));
- if (endptr != NULL)
- *endptr = (char *) nptr;
- return result * sign;
}
-
-
+# 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 (value, buflim, base, upper_case)
- unsigned long long int value;
- char *buflim;
- unsigned int base;
- int upper_case;
+_itoa (unsigned long long int value, char *buflim, unsigned int base,
+ int upper_case)
{
- extern const char INTUSE(_itoa_lower_digits)[] attribute_hidden;
-
assert (! upper_case);
do
- *--buflim = INTUSE(_itoa_lower_digits)[value % base];
+ *--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. */
}
weak_alias (__strsep, strsep)
strong_alias (__strsep, __strsep_g)
-
-
-/* The '_itoa_lower_digits' variable in libc.so is able to handle bases
- up to 36. We don't need this here. */
-const char INTUSE(_itoa_lower_digits)[16] attribute_hidden
- = "0123456789abcdef";
-
-
-
-#undef errno
-/* The 'errno' in ld.so is not exported. */
-#if USE_TLS && HAVE___THREAD
-extern __thread int errno attribute_hidden;
-#else
-extern int errno attribute_hidden;
-
-int *
-__errno_location (void)
-{
- return &errno;
-}
-#endif
projects / thirdparty / glibc.git / blobdiff