stdlib/tst-makecontext.c

   1 /* Copyright (C) 2006-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <ucontext.h>
  22 #include <assert.h>
  23 #include <unwind.h>
  24 #include <dlfcn.h>
  25 #include <gnu/lib-names.h>
  26
  27 ucontext_t ucp;
  28 char st1[16384];
  29 __thread int thr;
  30
  31 int somevar = -76;
  32 long othervar = -78L;
  33
  34 struct trace_arg
  35 {
  36   int cnt, size;
  37 };
  38
  39 static _Unwind_Reason_Code
  40 backtrace_helper (struct _Unwind_Context *ctx, void *a)
  41 {
  42   struct trace_arg *arg = a;
  43   if (++arg->cnt == arg->size)
  44     return _URC_END_OF_STACK;
  45   return _URC_NO_REASON;
  46 }
  47
  48 void
  49 cf (int i)
  50 {
  51   struct trace_arg arg = { .size = 100, .cnt = -1 };
  52   void *handle;
  53   _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
  54
  55   if (i != othervar || thr != 94)
  56     {
  57       printf ("i %d thr %d\n", i, thr);
  58       exit (1);
  59     }
  60
  61   /* Test if callback function of _Unwind_Backtrace is not called infinitely
  62      times. See Bug 18508 or gcc bug "Bug 66303 - runtime.Caller() returns
  63      infinitely deep stack frames on s390x.".
  64      The go runtime calls backtrace_full() in
  65      <gcc-src>/libbacktrace/backtrace.c, which uses _Unwind_Backtrace().  */
  66   handle = dlopen (LIBGCC_S_SO, RTLD_LAZY);
  67   if (handle != NULL)
  68     {
  69       unwind_backtrace = dlsym (handle, "_Unwind_Backtrace");
  70       if (unwind_backtrace != NULL)
  71         {
  72           unwind_backtrace (backtrace_helper, &arg);
  73           assert (arg.cnt != -1 && arg.cnt < 100);
  74         }
  75       dlclose (handle);
  76     }
  77
  78   /* Since uc_link below has been set to NULL, setcontext is supposed to
  79      terminate the process normally after this function returns.  */
  80 }
  81
  82 int
  83 do_test (void)
  84 {
  85   if (getcontext (&ucp) != 0)
  86     {
  87       if (errno == ENOSYS)
  88         {
  89           puts ("context handling not supported");
  90           return 0;
  91         }
  92
  93       puts ("getcontext failed");
  94       return 1;
  95     }
  96   thr = 94;
  97   ucp.uc_link = NULL;
  98   ucp.uc_stack.ss_sp = st1;
  99   ucp.uc_stack.ss_size = sizeof st1;
 100   makecontext (&ucp, (void (*) (void)) cf, 1, somevar - 2);
 101   if (setcontext (&ucp) != 0)
 102     {
 103       puts ("setcontext failed");
 104       return 1;
 105     }
 106   return 2;
 107 }
 108
 109 #define TEST_FUNCTION do_test ()
 110 #include "../test-skeleton.c"