debug/tst-backtrace5.c

   1 /* Test backtrace and backtrace_symbols for signal frames, where a
   2    system call was interrupted by a signal.
   3    Copyright (C) 2011-2022 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <execinfo.h>
  21 #include <search.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <signal.h>
  27 #include <unistd.h>
  28
  29 #include "tst-backtrace.h"
  30
  31 #ifndef SIGACTION_FLAGS
  32 # define SIGACTION_FLAGS 0
  33 #endif
  34
  35 /* The backtrace should include at least handle_signal, a signal
  36    trampoline, read, 3 * fn, and do_test.  */
  37 #define NUM_FUNCTIONS 7
  38
  39 void
  40 handle_signal (int signum)
  41 {
  42   void *addresses[NUM_FUNCTIONS];
  43   char **symbols;
  44   int n;
  45   int i;
  46
  47   /* Get the backtrace addresses.  */
  48   n = backtrace (addresses, sizeof (addresses) / sizeof (addresses[0]));
  49   printf ("Obtained backtrace with %d functions\n", n);
  50   /*  Check that there are at least seven functions.  */
  51   if (n < NUM_FUNCTIONS)
  52     {
  53       FAIL ();
  54       return;
  55     }
  56   /* Convert them to symbols.  */
  57   symbols = backtrace_symbols (addresses, n);
  58   /* Check that symbols were obtained.  */
  59   if (symbols == NULL)
  60     {
  61       FAIL ();
  62       return;
  63     }
  64   for (i = 0; i < n; ++i)
  65     printf ("Function %d: %s\n", i, symbols[i]);
  66   /* Check that the function names obtained are accurate.  */
  67   if (!match (symbols[0], "handle_signal"))
  68     {
  69       FAIL ();
  70       return;
  71     }
  72
  73   /* Do not check name for signal trampoline or cancellable syscall
  74      wrappers (__syscall_cancel*).  */
  75   for (; i < n - 1; i++)
  76     if (match (symbols[i], "read"))
  77       break;
  78   if (i == n - 1)
  79     {
  80       FAIL ();
  81       return;
  82     }
  83
  84   for (; i < n - 1; i++)
  85     if (!match (symbols[i], "fn"))
  86       {
  87         FAIL ();
  88         return;
  89       }
  90   /* Symbol names are not available for static functions, so we do not
  91      check do_test.  */
  92
  93   /* Check that backtrace does not return more than what fits in the array
  94      (bug 25423).  */
  95   for (int j = 0; j < NUM_FUNCTIONS; j++)
  96     {
  97       n = backtrace (addresses, j);
  98       if (n > j)
  99         {
 100           FAIL ();
 101           return;
 102         }
 103     }
 104 }
 105
 106 NO_INLINE int
 107 fn (int c, int flags)
 108 {
 109   pid_t parent_pid, child_pid;
 110   int pipefd[2];
 111   char r[1];
 112   struct sigaction act;
 113
 114   if (c > 0)
 115     {
 116       fn (c - 1, flags);
 117       return x;
 118     }
 119
 120   memset (&act, 0, sizeof (act));
 121   act.sa_handler = handle_signal;
 122   act.sa_flags = flags;
 123   sigemptyset (&act.sa_mask);
 124   sigaction (SIGUSR1, &act, NULL);
 125   parent_pid = getpid ();
 126   if (pipe (pipefd) == -1)
 127     abort ();
 128
 129   child_pid = fork ();
 130   if (child_pid == (pid_t) -1)
 131     abort ();
 132   else if (child_pid == 0)
 133     {
 134       sleep (1);
 135       kill (parent_pid, SIGUSR1);
 136       _exit (0);
 137     }
 138
 139   /* In the parent.  */
 140   read (pipefd[0], r, 1);
 141
 142   return 0;
 143 }
 144
 145 NO_INLINE int
 146 do_test (void)
 147 {
 148   fn (2, SIGACTION_FLAGS);
 149   return ret;
 150 }
 151
 152 #include <support/test-driver.c>