stdlib/tst-setcontext3.c

   1 /* Bug 18125: Verify setcontext calls exit() and not _exit().
   2    Copyright (C) 2015-2023 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 <errno.h>
  20 #include <signal.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <ucontext.h>
  25 #include <unistd.h>
  26 #include <limits.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <fcntl.h>
  30
  31 /* Please note that depending on the outcome of Bug 18135 this test
  32    may become invalid, and instead of testing for calling exit it
  33    should be reworked to test for the last context calling
  34    pthread_exit().  */
  35
  36 static ucontext_t ctx;
  37 static char *filename;
  38
  39 /* It is intended that this function does nothing.  */
  40 static void
  41 cf (void)
  42 {
  43   printf ("called context function\n");
  44 }
  45
  46 static void
  47 exit_called (void)
  48 {
  49   int fd;
  50   ssize_t res;
  51   const char buf[] = "Called exit function\n";
  52
  53   fd = open (filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
  54   if (fd == -1)
  55     {
  56       printf ("FAIL: Unable to create test file %s\n", filename);
  57       exit (1);
  58     }
  59   res = write (fd, buf, sizeof (buf));
  60   if (res != sizeof (buf))
  61     {
  62       printf ("FAIL: Expected to write test file in one write call.\n");
  63       exit (1);
  64     }
  65   res = close (fd);
  66   if (res == -1)
  67     {
  68       printf ("FAIL: Failed to close test file.\n");
  69       exit (1);
  70     }
  71   printf ("PASS: %s", buf);
  72 }
  73
  74 /* The test expects a filename given by the wrapper calling script.
  75    The test then registers an atexit handler that will create the
  76    file to indicate that the atexit handler ran. Then the test
  77    creates a context, modifies it with makecontext, and sets it.
  78    The context has only a single context which then must exit.
  79    If it incorrectly exits via _exit then the atexit handler is
  80    not run, the file is not created, and the wrapper detects this
  81    and fails the test.  This test cannot be done using an _exit
  82    interposer since setcontext avoids the PLT and calls _exit
  83    directly.  */
  84 static int
  85 do_test (int argc, char **argv)
  86 {
  87   int ret;
  88   char st1[32768];
  89   ucontext_t tempctx = ctx;
  90
  91   if (argc < 2)
  92     {
  93       printf ("FAIL: Test missing filename argument.\n");
  94       exit (1);
  95     }
  96
  97   filename = argv[1];
  98
  99   atexit (exit_called);
 100
 101   puts ("making contexts");
 102   if (getcontext (&ctx) != 0)
 103     {
 104       if (errno == ENOSYS)
 105         {
 106           /* Exit with 77 to mark the test as UNSUPPORTED.  */
 107           printf ("UNSUPPORTED: getcontext not implemented.\n");
 108           exit (77);
 109         }
 110
 111       printf ("FAIL: getcontext failed.\n");
 112       exit (1);
 113     }
 114
 115   ctx.uc_stack.ss_sp = st1;
 116   ctx.uc_stack.ss_size = sizeof (st1);
 117   ctx.uc_link = 0;
 118   makecontext (&ctx, cf, 0);
 119
 120   /* Without this check, a stub makecontext can make us spin forever.  */
 121   if (memcmp (&tempctx, &ctx, sizeof ctx) == 0)
 122     {
 123       puts ("UNSUPPORTED: makecontext was a no-op, presuming not implemented");
 124       exit (77);
 125     }
 126
 127   ret = setcontext (&ctx);
 128   if (ret != 0)
 129     {
 130       printf ("FAIL: setcontext returned with %d and errno of %d.\n", ret, errno);
 131       exit (1);
 132     }
 133
 134   printf ("FAIL: Impossibly returned to main.\n");
 135   exit (1);
 136 }
 137
 138 #include "../test-skeleton.c"