/* Minimal replacements for basic facilities used in the dynamic linker. Copyright (C) 1995-2015 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, see <http://www.gnu.org/licenses/>. */ #include <errno.h> #include <limits.h> #include <stdio.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 <_itoa.h> #include <assert.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); /* Allocate an aligned memory block. */ void * weak_function __libc_memalign (size_t align, size_t n) { 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) + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1)); } /* Make sure the allocation pointer is ideally aligned. */ alloc_ptr = (void *) 0 + (((alloc_ptr - (void *) 0) + align - 1) & ~(align - 1)); if (alloc_ptr + n >= alloc_end || n >= -(uintptr_t) alloc_ptr) { /* Insufficient space left; allocate another page. */ caddr_t page; size_t nup = (n + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1); if (__glibc_unlikely (nup == 0)) { if (n) return NULL; nup = GLRO(dl_pagesize); } page = __mmap (0, nup, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0); if (page == MAP_FAILED) return NULL; if (page != alloc_end) alloc_ptr = page; alloc_end = page + nup; } alloc_last_block = (void *) alloc_ptr; alloc_ptr += n; return alloc_last_block; } void * weak_function malloc (size_t n) { return __libc_memalign (sizeof (double), n); } /* 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) { /* New memory from the trivial malloc above is always already cleared. (We make sure that's true in the rare occasion it might not be, by clearing memory in free, below.) */ size_t bytes = nmemb * size; #define HALF_SIZE_T (((size_t) 1) << (8 * sizeof (size_t) / 2)) if (__builtin_expect ((nmemb | size) >= HALF_SIZE_T, 0) && size != 0 && bytes / size != nmemb) return NULL; return malloc (bytes); } /* This will rarely be called. */ void weak_function free (void *ptr) { /* We can free only the last block allocated. */ if (ptr == alloc_last_block) { /* Since this is rare, we clear the freed block here so that calloc can presume malloc returns cleared memory. */ memset (alloc_last_block, '\0', alloc_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) { if (ptr == NULL) return malloc (n); assert (ptr == alloc_last_block); size_t old_size = alloc_ptr - alloc_last_block; alloc_ptr = alloc_last_block; void *new = malloc (n); return new != ptr ? memcpy (new, ptr, old_size) : new; } /* Avoid signal frobnication in setjmp/longjmp. Keeps things smaller. */ #include <setjmp.h> int weak_function __sigjmp_save (sigjmp_buf env, int savemask __attribute__ ((unused))) { env[0].__mask_was_saved = 0; return 0; } /* 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_r (int errnum, char *buf, size_t buflen) { char *msg; switch (errnum) { case ENOMEM: msg = (char *) "Cannot allocate memory"; break; case EINVAL: msg = (char *) "Invalid argument"; break; case ENOENT: msg = (char *) "No such file or directory"; break; case EPERM: msg = (char *) "Operation not permitted"; break; case EIO: msg = (char *) "Input/output error"; break; case EACCES: msg = (char *) "Permission denied"; break; default: /* No need to check buffer size, all calls in the dynamic linker provide enough space. */ buf[buflen - 1] = '\0'; msg = _itoa (errnum, buf + buflen - 1, 10, 0); msg = memcpy (msg - (sizeof ("Error ") - 1), "Error ", sizeof ("Error ") - 1); break; } return msg; } 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. */ void weak_function __assert_fail (const char *assertion, const char *file, unsigned int line, const char *function) { _dl_fatal_printf ("\ Inconsistency detected by ld.so: %s: %u: %s%sAssertion `%s' failed!\n", file, line, function ?: "", function ? ": " : "", assertion); } rtld_hidden_weak (__assert_fail) void weak_function __assert_perror_fail (int errnum, const char *file, unsigned int line, const char *function) { 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)); } rtld_hidden_weak (__assert_perror_fail) #endif unsigned long int weak_function __strtoul_internal (const char *nptr, char **endptr, int base, int group) { unsigned long int result = 0; long int sign = 1; unsigned max_digit; 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; max_digit = 9; if (*nptr == '0') { if (nptr[1] == 'x' || nptr[1] == 'X') { base = 16; nptr += 2; } else { base = 8; max_digit = 7; } } while (1) { unsigned long int digval; if (*nptr >= '0' && *nptr <= '0' + max_digit) digval = *nptr - '0'; else if (base == 16) { if (*nptr >= 'a' && *nptr <= 'f') digval = *nptr - 'a' + 10; else if (*nptr >= 'A' && *nptr <= 'F') digval = *nptr - 'A' + 10; else break; } else break; if (result > ULONG_MAX / base || (result == ULONG_MAX / base && digval > ULONG_MAX % base)) { errno = ERANGE; if (endptr != NULL) *endptr = (char *) nptr; return ULONG_MAX; } result *= base; result += digval; ++nptr; } if (endptr != NULL) *endptr = (char *) nptr; return result * sign; } #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; { 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) /* 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)