sysdeps/posix/libc_fatal.c

   1 /* Catastrophic failure reports.  Generic POSIX.1 version.
   2    Copyright (C) 1993-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <atomic.h>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <ldsodefs.h>
  23 #include <paths.h>
  24 #include <stdarg.h>
  25 #include <stdbool.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sysdep.h>
  30 #include <unistd.h>
  31 #include <sys/mman.h>
  32 #include <sys/uio.h>
  33 #include <not-cancel.h>
  34 #include <setvmaname.h>
  35
  36 #ifdef FATAL_PREPARE_INCLUDE
  37 #include FATAL_PREPARE_INCLUDE
  38 #endif
  39
  40 #ifndef WRITEV_FOR_FATAL
  41 # define WRITEV_FOR_FATAL       writev_for_fatal
  42 static bool
  43 writev_for_fatal (int fd, const struct iovec *iov, size_t niov, size_t total)
  44 {
  45   return TEMP_FAILURE_RETRY (__writev (fd, iov, niov)) == total;
  46 }
  47 #endif
  48
  49 /* Abort with an error message.  */
  50 void
  51 __libc_message_impl (const char *fmt, ...)
  52 {
  53   va_list ap;
  54   int fd = -1;
  55
  56 #ifdef FATAL_PREPARE
  57   FATAL_PREPARE;
  58 #endif
  59
  60   if (fd == -1)
  61     fd = STDERR_FILENO;
  62
  63   struct iovec iov[LIBC_MESSAGE_MAX_ARGS * 2 - 1];
  64   int iovcnt = 0;
  65   ssize_t total = 0;
  66
  67   va_start (ap, fmt);
  68   const char *cp = fmt;
  69   while (*cp != '\0')
  70     {
  71       /* Find the next "%s" or the end of the string.  */
  72       const char *next = cp;
  73       while (next[0] != '%' || next[1] != 's')
  74         {
  75           next = __strchrnul (next + 1, '%');
  76
  77           if (next[0] == '\0')
  78             break;
  79         }
  80
  81       /* Determine what to print.  */
  82       const char *str;
  83       size_t len;
  84       if (cp[0] == '%' && cp[1] == 's')
  85         {
  86           str = va_arg (ap, const char *);
  87           len = strlen (str);
  88           cp += 2;
  89         }
  90       else
  91         {
  92           str = cp;
  93           len = next - cp;
  94           cp = next;
  95         }
  96
  97       iov[iovcnt].iov_base = (char *) str;
  98       iov[iovcnt].iov_len = len;
  99       total += len;
 100       iovcnt++;
 101     }
 102   va_end (ap);
 103
 104   if (iovcnt > 0)
 105     {
 106       WRITEV_FOR_FATAL (fd, iov, iovcnt, total);
 107
 108       total = (total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1);
 109       struct abort_msg_s *buf = __mmap (NULL, total,
 110                                         PROT_READ | PROT_WRITE,
 111                                         MAP_ANON | MAP_PRIVATE, -1, 0);
 112       if (__glibc_likely (buf != MAP_FAILED))
 113         {
 114           buf->size = total;
 115           char *wp = buf->msg;
 116           for (int cnt = 0; cnt < iovcnt; ++cnt)
 117             wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
 118           *wp = '\0';
 119
 120           __set_vma_name (buf, total, " glibc: fatal");
 121
 122           /* We have to free the old buffer since the application might
 123              catch the SIGABRT signal.  */
 124           struct abort_msg_s *old = atomic_exchange_acquire (&__abort_msg,
 125                                                              buf);
 126           if (old != NULL)
 127             __munmap (old, old->size);
 128         }
 129     }
 130
 131   /* Kill the application.  */
 132   abort ();
 133 }
 134
 135
 136 void
 137 __libc_fatal (const char *message)
 138 {
 139   /* The loop is added only to keep gcc happy.  */
 140   while (1)
 141     __libc_message ("%s", message);
 142 }
 143 libc_hidden_def (__libc_fatal)