sysdeps/posix/libc_fatal.c

   1 /* Catastrophic failure reports.  Generic POSIX.1 version.
   2    Copyright (C) 1993-2023 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
  35 #ifdef FATAL_PREPARE_INCLUDE
  36 #include FATAL_PREPARE_INCLUDE
  37 #endif
  38
  39 #ifndef WRITEV_FOR_FATAL
  40 # define WRITEV_FOR_FATAL       writev_for_fatal
  41 static bool
  42 writev_for_fatal (int fd, const struct iovec *iov, size_t niov, size_t total)
  43 {
  44   return TEMP_FAILURE_RETRY (__writev (fd, iov, niov)) == total;
  45 }
  46 #endif
  47
  48 /* Abort with an error message.  */
  49 void
  50 __libc_message_impl (const char *fmt, ...)
  51 {
  52   va_list ap;
  53   int fd = -1;
  54
  55 #ifdef FATAL_PREPARE
  56   FATAL_PREPARE;
  57 #endif
  58
  59   if (fd == -1)
  60     fd = STDERR_FILENO;
  61
  62   struct iovec iov[LIBC_MESSAGE_MAX_ARGS * 2 - 1];
  63   int iovcnt = 0;
  64   ssize_t total = 0;
  65
  66   va_start (ap, fmt);
  67   const char *cp = fmt;
  68   while (*cp != '\0')
  69     {
  70       /* Find the next "%s" or the end of the string.  */
  71       const char *next = cp;
  72       while (next[0] != '%' || next[1] != 's')
  73         {
  74           next = __strchrnul (next + 1, '%');
  75
  76           if (next[0] == '\0')
  77             break;
  78         }
  79
  80       /* Determine what to print.  */
  81       const char *str;
  82       size_t len;
  83       if (cp[0] == '%' && cp[1] == 's')
  84         {
  85           str = va_arg (ap, const char *);
  86           len = strlen (str);
  87           cp += 2;
  88         }
  89       else
  90         {
  91           str = cp;
  92           len = next - cp;
  93           cp = next;
  94         }
  95
  96       iov[iovcnt].iov_base = (char *) str;
  97       iov[iovcnt].iov_len = len;
  98       total += len;
  99       iovcnt++;
 100     }
 101   va_end (ap);
 102
 103   if (iovcnt > 0)
 104     {
 105       WRITEV_FOR_FATAL (fd, iov, iovcnt, total);
 106
 107       total = (total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1);
 108       struct abort_msg_s *buf = __mmap (NULL, total,
 109                                         PROT_READ | PROT_WRITE,
 110                                         MAP_ANON | MAP_PRIVATE, -1, 0);
 111       if (__glibc_likely (buf != MAP_FAILED))
 112         {
 113           buf->size = total;
 114           char *wp = buf->msg;
 115           for (int cnt = 0; cnt < iovcnt; ++cnt)
 116             wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
 117           *wp = '\0';
 118
 119           /* We have to free the old buffer since the application might
 120              catch the SIGABRT signal.  */
 121           struct abort_msg_s *old = atomic_exchange_acquire (&__abort_msg,
 122                                                              buf);
 123           if (old != NULL)
 124             __munmap (old, old->size);
 125         }
 126     }
 127
 128   /* Kill the application.  */
 129   abort ();
 130 }
 131
 132
 133 void
 134 __libc_fatal (const char *message)
 135 {
 136   /* The loop is added only to keep gcc happy.  */
 137   while (1)
 138     __libc_message ("%s", message);
 139 }
 140 libc_hidden_def (__libc_fatal)