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/* distilled from m4:
* $ echo 'define(a,a(a))a' | m4
*
* Basically, we use libsigsegv to install segfault and overflow handlers.
* Then we overflow the stack. The segfault handler should be called. Then
* we return, libsigsegv detects the overflow and then calls the overflow
* handler.
*/
#include "tests.h"
#define WRITE(msg) ({ ssize_t w = write(1, msg, sizeof(msg) - 1); w; })
#if defined(HAVE_SIGSEGV_H) && defined(HAVE_LIBSIGSEGV)
#include <sigsegv.h>
static int segv_handler(void *address, int serious)
{
WRITE("caught segv ... ");
if (!serious)
return 0;
WRITE("FAIL: wtf, it's serious!");
_exit(1);
}
static void overflow_handler(int emergency, stackoverflow_context_t context)
{
WRITE("OVERFLOW: OK!\n");
_exit(0);
}
static union
{
char buffer[SIGSTKSZ];
long double ld;
long l;
void *p;
} alternate_signal_stack;
int recursive(int i)
{
char stack_fatty[1024];
int ret = sprintf(stack_fatty, "%i", i);
if (i <= 0)
return i + ret;
else
return recursive(i + ret);
}
int main(int argc, char *argv[])
{
int ret;
ret = stackoverflow_install_handler(overflow_handler,
alternate_signal_stack.buffer, sizeof alternate_signal_stack.buffer);
if (ret)
err("stackoverflow_install_handler() failed");
ret = sigsegv_install_handler(segv_handler);
if (ret)
err("sigsegv_install_handler() failed");
WRITE("starting overflow ... ");
recursive(argc);
return 0;
}
#else
int main()
{
WRITE("starting overflow ... ");
WRITE("caught segv ... ");
WRITE("OVERFLOW: OK!\n");
return 0;
}
#endif
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