gdb/testsuite/gdb.base/coremaker.c

   1 /* Copyright 1992-2023 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Simple little program that just generates a core dump from inside some
  19    nested function calls. */
  20
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23 #include <fcntl.h>
  24 #include <sys/mman.h>
  25 #include <signal.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <string.h>
  29
  30 #ifndef __STDC__
  31 #define const   /**/
  32 #endif
  33
  34 #define MAPSIZE (8 * 1024)
  35
  36 /* Don't make these automatic vars or we will have to walk back up the
  37    stack to access them. */
  38
  39 char *buf1;
  40 char *buf2;
  41 char *buf2ro;
  42 char *buf3;
  43
  44 int coremaker_data = 1; /* In Data section */
  45 int coremaker_bss;      /* In BSS section */
  46
  47 /* Place a chunk of memory before coremaker_ro to improve the chances
  48    that coremaker_ro will end up on its own page.  See:
  49
  50    https://sourceware.org/pipermail/gdb-patches/2020-May/168168.html
  51    https://sourceware.org/pipermail/gdb-patches/2020-May/168170.html  */
  52 const unsigned char filler_ro[MAPSIZE] = {1, 2, 3, 4, 5, 6, 7, 8};
  53 const int coremaker_ro = 201;   /* In Read-Only Data section */
  54
  55 /* Note that if the mapping fails for any reason, we set buf2
  56    to -1 and the testsuite notices this and reports it as
  57    a failure due to a mapping error.  This way we don't have
  58    to test for specific errors when running the core maker. */
  59
  60 void
  61 mmapdata ()
  62 {
  63   int j, fd;
  64
  65   /* Allocate and initialize a buffer that will be used to write
  66      the file that is later mapped in. */
  67
  68   buf1 = (char *) malloc (MAPSIZE);
  69   for (j = 0; j < MAPSIZE; ++j)
  70     {
  71       buf1[j] = j;
  72     }
  73
  74   /* Write the file to map in */
  75
  76   fd = open ("coremmap.data", O_CREAT | O_RDWR, 0666);
  77   if (fd == -1)
  78     {
  79       perror ("coremmap.data open failed");
  80       buf2 = (char *) -1;
  81       return;
  82     }
  83   write (fd, buf1, MAPSIZE);
  84
  85   /* Now map the file into our address space as buf2 */
  86
  87   buf2 = (char *) mmap (0, MAPSIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
  88   if (buf2 == (char *) MAP_FAILED)
  89     {
  90       perror ("mmap failed");
  91       return;
  92     }
  93
  94   /* Map in another copy, read-only.  We won't write to this copy so it
  95      will likely not end up in the core file.  */
  96   buf2ro = (char *) mmap (0, MAPSIZE, PROT_READ, MAP_PRIVATE, fd, 0);
  97   if (buf2ro == (char *) -1)
  98     {
  99       perror ("mmap failed");
 100       return;
 101     }
 102
 103   /* Verify that the original data and the mapped data are identical.
 104      If not, we'd rather fail now than when trying to access the mapped
 105      data from the core file. */
 106
 107   for (j = 0; j < MAPSIZE; ++j)
 108     {
 109       if (buf1[j] != buf2[j] || buf1[j] != buf2ro[j])
 110         {
 111           fprintf (stderr, "mapped data is incorrect");
 112           buf2 = buf2ro = (char *) -1;
 113           return;
 114         }
 115     }
 116   /* Touch buf2 so kernel writes it out into 'core'. */
 117   buf2[0] = buf1[0];
 118
 119   /* Create yet another region which is allocated, but not written to.  */
 120   buf3 = mmap (NULL, MAPSIZE, PROT_READ | PROT_WRITE,
 121                MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 122   if (buf3 == (char *) -1)
 123     {
 124       perror ("mmap failed");
 125       return;
 126     }
 127 }
 128
 129 void
 130 func2 ()
 131 {
 132   int coremaker_local[5];
 133   int i;
 134
 135 #ifdef SA_FULLDUMP
 136   /* Force a corefile that includes the data section for AIX.  */
 137   {
 138     struct sigaction sa;
 139
 140     sigaction (SIGABRT, (struct sigaction *)0, &sa);
 141     sa.sa_flags |= SA_FULLDUMP;
 142     sigaction (SIGABRT, &sa, (struct sigaction *)0);
 143   }
 144 #endif
 145
 146   /* Make sure that coremaker_local doesn't get optimized away. */
 147   for (i = 0; i < 5; i++)
 148     coremaker_local[i] = i;
 149   coremaker_bss = 0;
 150   for (i = 0; i < 5; i++)
 151     coremaker_bss += coremaker_local[i];
 152   coremaker_data = coremaker_ro + 1;
 153   abort ();
 154 }
 155
 156 void
 157 func1 ()
 158 {
 159   func2 ();
 160 }
 161
 162 int
 163 main (int argc, char **argv)
 164 {
 165   if (argc == 2 && strcmp (argv[1], "sleep") == 0)
 166     {
 167       sleep (60);
 168       return 0;
 169     }
 170   mmapdata ();
 171   func1 ();
 172   return 0;
 173 }