03-16-2010
Most unix implementations have the equivalent of an interrupt stack.
SIGSEGV is generated by the OS, not by your process.
TOP:
Your code tries to access out-of-bounds memory. The OS does not allow this, it raises SIGSEGV instead. SIGSEGV signal calls your signal/interrupt handler on the interrupt stack. As soon as the signal handler exits, the interrup stacks pops the offending instruction off the interrupt stack. Then the old, exact same, offending machine code instruction resumes right where it left off - So
goto TOP
Signals do not cure problems. They alert you to them.
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LEARN ABOUT OPENSOLARIS
stack_violation
stack_violation(3C) Standard C Library Functions stack_violation(3C)
NAME
stack_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 represent 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.
";
else
str = "no stack violation.
";
(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 ALSO
sigaction(2), sigaltstack(2), stack_getbounds(3C), stack_inbounds(3C), stack_setbounds(3C), attributes(5)
SunOS 5.11 18 Jul 2002 stack_violation(3C)