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/* $OpenBSD: sigaltstack_fork.c,v 1.2 2011/11/26 04:11:34 guenther Exp $ */
/*
* Public domain. 2011, Joshua Elsasser
*
* Test if child processes inherit an alternate signal stack.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <err.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
void
check_stack(void *buf, const char *label)
{
struct sigaltstack ss;
bzero(&ss, sizeof(ss));
if (sigaltstack(NULL, &ss) != 0)
err(1, "failed to get sigaltstack in %s", label);
if (ss.ss_sp != buf ||
ss.ss_size != SIGSTKSZ ||
ss.ss_flags != 0)
errx(1, "bad sigaltstack value in %s: "
"buf=%p ss_sp=%p ss_size=%zu ss_flags=0x%x",
label, buf, ss.ss_sp, ss.ss_size, ss.ss_flags);
}
int
main(int argc, char *argv[])
{
struct sigaltstack ss;
int status;
pid_t kid;
void *buf;
if ((buf = malloc(SIGSTKSZ)) == NULL)
err(1, "malloc failed");
bzero(&ss, sizeof(ss));
ss.ss_sp = buf;
ss.ss_size = SIGSTKSZ;
if (sigaltstack(&ss, NULL) != 0)
err(1, "failed to set sigaltstack");
check_stack(buf, "parent");
if ((kid = fork()) == -1)
err(1, "fork failed");
if (kid == 0) {
check_stack(buf, "child");
_exit(0);
}
if (waitpid(kid, &status, 0) != kid)
err(1, "waitpid failed");
if (!WIFEXITED(status))
errx(1, "child did not exit normally");
return (WEXITSTATUS(status));
}
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