assert/assert.c

   1 /* Copyright (C) 1991-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <assert.h>
  19 #include <atomic.h>
  20 #include <ldsodefs.h>
  21 #include <libintl.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <sysdep.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27 #include <setvmaname.h>
  28
  29
  30 extern const char *__progname;
  31
  32 #include <wchar.h>
  33 #include <libio/iolibio.h>
  34 #define fflush(s) _IO_fflush (s)
  35
  36 /* This function, when passed a string containing an asserted
  37    expression, a filename, and a line number, prints a message
  38    on the standard error stream of the form:
  39         a.c:10: foobar: Assertion `a == b' failed.
  40    It then aborts program execution via a call to `abort'.  */
  41
  42 #ifdef FATAL_PREPARE_INCLUDE
  43 # include FATAL_PREPARE_INCLUDE
  44 #endif
  45
  46
  47 void
  48 __assert_fail_base (const char *fmt, const char *assertion, const char *file,
  49                     unsigned int line, const char *function)
  50 {
  51   char *str;
  52
  53 #ifdef FATAL_PREPARE
  54   FATAL_PREPARE;
  55 #endif
  56
  57   int total;
  58   if (__asprintf (&str, fmt,
  59                   __progname, __progname[0] ? ": " : "",
  60                   file, line,
  61                   function ? function : "", function ? ": " : "",
  62                   assertion, &total) >= 0)
  63     {
  64       /* Print the message.  */
  65       (void) __fxprintf (NULL, "%s", str);
  66       (void) fflush (stderr);
  67
  68       total = (total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1);
  69       struct abort_msg_s *buf = __mmap (NULL, total, PROT_READ | PROT_WRITE,
  70                                         MAP_ANON | MAP_PRIVATE, -1, 0);
  71       if (__glibc_likely (buf != MAP_FAILED))
  72         {
  73           buf->size = total;
  74           strcpy (buf->msg, str);
  75           __set_vma_name (buf, total, " glibc: assert");
  76
  77           /* We have to free the old buffer since the application might
  78              catch the SIGABRT signal.  */
  79           struct abort_msg_s *old = atomic_exchange_acquire (&__abort_msg, buf);
  80
  81           if (old != NULL)
  82             __munmap (old, old->size);
  83         }
  84
  85       free (str);
  86     }
  87   else
  88     {
  89       /* At least print a minimal message.  */
  90       static const char errstr[] = "Unexpected error.\n";
  91       __libc_write (STDERR_FILENO, errstr, sizeof (errstr) - 1);
  92     }
  93
  94   abort ();
  95 }
  96
  97
  98 #undef __assert_fail
  99 void
 100 __assert_fail (const char *assertion, const char *file, unsigned int line,
 101                const char *function)
 102 {
 103   __assert_fail_base (_("%s%s%s:%u: %s%sAssertion `%s' failed.\n%n"),
 104                       assertion, file, line, function);
 105 }