nptl/tst-pthread-getattr.c

   1 /* Make sure that the stackaddr returned by pthread_getattr_np is
   2    reachable.
   3
   4    Copyright (C) 2012 Free Software Foundation, Inc.
   5    This file is part of the GNU C Library.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <sys/resource.h>
  24 #include <pthread.h>
  25 #include <alloca.h>
  26
  27 /* Move the stack pointer so that stackaddr is accessible and then check if it
  28    really is accessible.  This will segfault if it fails.  */
  29 static void
  30 allocate_and_test (void *stackaddr)
  31 {
  32   void *mem = &mem;
  33   /* FIXME:  The difference will be negative for _STACK_GROWSUP.  */
  34   mem = alloca ((size_t) (mem - stackaddr));
  35   *(int *)(mem) = 0;
  36 }
  37
  38 static int
  39 get_self_pthread_attr (const char *id, void **stackaddr, size_t *stacksize)
  40 {
  41   pthread_attr_t attr;
  42   int ret;
  43   pthread_t me = pthread_self ();
  44
  45   if ((ret = pthread_getattr_np (me, &attr)))
  46     {
  47       printf ("%s: pthread_getattr_np failed: %s\n", id, strerror (ret));
  48       return 1;
  49     }
  50
  51   if ((ret = pthread_attr_getstack (&attr, stackaddr, stacksize)))
  52     {
  53       printf ("%s: pthread_attr_getstack returned error: %s\n", id,
  54               strerror (ret));
  55       return 1;
  56     }
  57
  58   return 0;
  59 }
  60
  61 /* Verify that the stack size returned by pthread_getattr_np is usable when
  62    the returned value is subject to rlimit.  */
  63 static int
  64 check_stack_top (void)
  65 {
  66   struct rlimit stack_limit;
  67   void *stackaddr;
  68   size_t stacksize = 0;
  69   int ret;
  70
  71   puts ("Verifying that stack top is accessible");
  72
  73   ret = getrlimit (RLIMIT_STACK, &stack_limit);
  74   if (ret)
  75     {
  76       perror ("getrlimit failed");
  77       return 1;
  78     }
  79
  80   if (get_self_pthread_attr ("check_stack_top", &stackaddr, &stacksize))
  81     return 1;
  82
  83   /* Reduce the rlimit to a page less that what is currently being returned so
  84      that we ensure that pthread_getattr_np uses rlimit.  The figure is
  85      intentionally unaligned so to verify that pthread_getattr_np returns an
  86      aligned stacksize that correctly fits into the rlimit.  We don't bother
  87      about the case where the stack is limited by the vma below it and not by
  88      the rlimit because the stacksize returned in that case is computed from
  89      the end of that vma and is hence safe.  */
  90   stack_limit.rlim_cur = stacksize - 4095;
  91   printf ("Adjusting RLIMIT_STACK to %zu\n", stack_limit.rlim_cur);
  92   if ((ret = setrlimit (RLIMIT_STACK, &stack_limit)))
  93     {
  94       perror ("setrlimit failed");
  95       return 1;
  96     }
  97
  98   if (get_self_pthread_attr ("check_stack_top2", &stackaddr, &stacksize))
  99     return 1;
 100
 101   printf ("Adjusted rlimit: stacksize=%zu, stackaddr=%p\n", stacksize,
 102           stackaddr);
 103   allocate_and_test (stackaddr);
 104
 105   puts ("Stack top tests done");
 106
 107   return 0;
 108 }
 109
 110 /* TODO: Similar check for thread stacks once the thread stack sizes are
 111    fixed.  */
 112 static int
 113 do_test (void)
 114 {
 115   return check_stack_top ();
 116 }
 117
 118
 119 #define TEST_FUNCTION do_test ()
 120 #include "../test-skeleton.c"