glibc/stdlib/tst-makecontext.c

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/* Copyright (C) 2006-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <ucontext.h>
#include <assert.h>
#include <unwind.h>
#include <dlfcn.h>
#include <gnu/lib-names.h>
ucontext_t ucp;
char st1[16384];
__thread int thr;
int somevar = -76;
long othervar = -78L;
struct trace_arg
{
int cnt, size;
};
static _Unwind_Reason_Code
backtrace_helper (struct _Unwind_Context *ctx, void *a)
{
struct trace_arg *arg = a;
if (++arg->cnt == arg->size)
return _URC_END_OF_STACK;
return _URC_NO_REASON;
}
void
cf (int i)
{
struct trace_arg arg = { .size = 100, .cnt = -1 };
void *handle;
_Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
if (i != othervar || thr != 94)
{
printf ("i %d thr %d\n", i, thr);
exit (1);
}
/* Test if callback function of _Unwind_Backtrace is not called infinitely
times. See Bug 18508 or gcc bug "Bug 66303 - runtime.Caller() returns
infinitely deep stack frames on s390x.".
The go runtime calls backtrace_full() in
<gcc-src>/libbacktrace/backtrace.c, which uses _Unwind_Backtrace(). */
handle = dlopen (LIBGCC_S_SO, RTLD_LAZY);
if (handle != NULL)
{
unwind_backtrace = dlsym (handle, "_Unwind_Backtrace");
if (unwind_backtrace != NULL)
{
unwind_backtrace (backtrace_helper, &arg);
assert (arg.cnt != -1 && arg.cnt < 100);
}
dlclose (handle);
}
/* Since uc_link below has been set to NULL, setcontext is supposed to
terminate the process normally after this function returns. */
}
int
do_test (void)
{
if (getcontext (&ucp) != 0)
{
if (errno == ENOSYS)
{
puts ("context handling not supported");
return 0;
}
puts ("getcontext failed");
return 1;
}
thr = 94;
ucp.uc_link = NULL;
ucp.uc_stack.ss_sp = st1;
ucp.uc_stack.ss_size = sizeof st1;
makecontext (&ucp, (void (*) (void)) cf, 1, somevar - 2);
if (setcontext (&ucp) != 0)
{
puts ("setcontext failed");
return 1;
}
return 2;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"