f.c

#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>

extern char **environ;

static void
die(const char *s)
{
       perror(s);
       exit(EXIT_FAILURE);
}

static void
printsigstack(const char *prefix)
{
        stack_t ss;

        if (sigaltstack(NULL, &ss) < 0)
                die("sigaltstack get");
        printf("%s - ss_sp=%p ss_size=%lu ss_flags=0x%x\n", prefix, ss.ss_sp,
            (unsigned long)ss.ss_size, (unsigned int)ss.ss_flags);
}

static void
setstack(void *arg)
{
        stack_t ss;

        ss.ss_sp = malloc(SIGSTKSZ);
        if (ss.ss_sp == NULL)
                die("malloc");

        ss.ss_size = SIGSTKSZ;
        ss.ss_flags = 0;
        if (sigaltstack(&ss, NULL) < 0)
                die("sigaltstack set");
}


static void *
thread(void *arg)
{
        char *argv[] = { "./test-sigs", "no-more", 0 };

        printsigstack("thread - before setstack");
        setstack(arg);
        printsigstack("thread - after setstack + before execve");

        execve(argv[0], &argv[0], environ);
        die("exec failed");

        return NULL;
}

int
main(int argc, char** argv)
{
        int i, j;
        int alloc_size = 32 * 1024;
        pthread_t tid;
        char buf[1024];
        void *arg;

        printf("argc: %d, %s\n", argc, argv[0]);
        printsigstack("main");
        if (argc != 1)
                return 0;

        j = pthread_create(&tid, NULL, thread, NULL);
        if (j != 0) {
               errno = i;
               die("pthread_create");
        }

        j = pthread_join(tid, NULL);
        if (j != 0) {
                errno = j;
                die("pthread_join");
        }

        return 0;
}