STACK_VIOLATION(3C)STACK_VIOLATION(3C)NAMEstack_violation - determine stack boundary violation event
SYNOPSIS
#include <ucontext.h>
int stack_violation(int sig, const siginfo_t *sip,
const ucontext_t *ucp);
DESCRIPTION
The stack_violation() function returns a boolean value indicating
whether the signal, sig, and accompanying signal information, sip, and
saved context, ucp, represent a stack boundary violation event or a
stack overflow.
RETURN VALUES
The stack_violation() function returns 0 if the signal does not repre‐
sent a stack boundary violation event and 1 if the signal does repre‐
sent a stack boundary violation event.
ERRORS
No errors are defined.
EXAMPLES
Example 1 Set up a signal handler to run on an alternate stack.
The following example sets up a signal handler for SIGSEGV to run on an
alternate signal stack. For each signal it handles, the handler emits a
message to indicate if the signal was produced due to a stack boundary
violation.
#include <stdlib.h>
#include <unistd.h>
#include <ucontext.h>
#include <signal.h>
static void
handler(int sig, siginfo_t *sip, void *p)
{
ucontext_t *ucp = p;
const char *str;
if (stack_violation(sig, sip, ucp))
str = "stack violation.\n";
else
str = "no stack violation.\n";
(void) write(STDERR_FILENO, str, strlen(str));
exit(1);
}
int
main(int argc, char **argv)
{
struct sigaction sa;
stack_t altstack;
altstack.ss_size = SIGSTKSZ;
altstack.ss_sp = malloc(SIGSTKSZ);
altstack.ss_flags = 0;
(void) sigaltstack(&altstack, NULL);
sa.sa_sigaction = handler;
(void) sigfillset(&sa.sa_mask);
sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
(void) sigaction(SIGSEGV, &sa, NULL);
/*
* The application is now set up to use stack_violation(3C).
*/
return (0);
}
USAGE
An application typically uses stack_violation() in a signal handler
that has been installed for SIGSEGV using sigaction(2) with the SA_SIG‐
INFO flag set and is configured to run on an alternate signal stack.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬───────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼───────────────────┤
│Interface Stability │ Evolving │
├────────────────────┼───────────────────┤
│MT-Level │ Async-Signal-Safe │
└────────────────────┴───────────────────┘
SEE ALSOsigaction(2), sigaltstack(2), stack_getbounds(3C), stack_inbounds(3C),
stack_setbounds(3C), attributes(5)
Jul 18, 2002 STACK_VIOLATION(3C)
