unwind.c

#define UNW_LOCAL_ONLY

#include <libunwind.h>

#include <signal.h>

#include <dlfcn.h>

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

void
ccc(void)
{
    printf("generating SEGV\n");
    *((int *)NULL) = 12;
}

void
bbb(void)
{
    ccc();
}

void
aaa(void)
{
    bbb();
}

void
show_backtrace(ucontext_t* context)
{
    unw_cursor_t  cursor;
    unw_word_t    ip, sp;

    int r = unw_init_local(&cursor, context);
    if (r < 0) {
        printf("unw_init_local failed\n");
        abort();
    }
    for (;;) {
        r = unw_step(&cursor);
        if (r == 0) {
            break;
        }
        if (r < 0) {
            printf("unw_step failed\n");
            abort();
        }
        unw_get_reg(&cursor, UNW_REG_IP, &ip);
        unw_get_reg(&cursor, UNW_REG_SP, &sp);
        printf("ip = %lx, sp = %lx\n", (long)ip, (long)sp);
        Dl_info        dli;
        memset(&dli, 0, sizeof dli);
        if (dladdr((void*) ip, &dli) && dli.dli_sname) {
            printf("%s\n", dli.dli_sname);
        }
    }
    abort();
}

void
my_handler(int sig, siginfo_t* ignore, ucontext_t* context)
{
    show_backtrace(context);
}

int
main(int argc, char *argv[])
{
    struct sigaction sa;
    sa.sa_sigaction = &my_handler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_SIGINFO;
    sigaction(SIGSEGV, &sa, NULL);
    aaa();
    return 0;
}