Print call stack by using libunwind

backtrace.c

#include <libunwind.h>
#include <libunwind-ptrace.h>

#include "backtrace.h"

#define MAX_BACKTRACE_FRAMES 64

void unwind(pid_t pid) {
    unw_addr_space_t addr_space = NULL;
    struct UPT_info* upt_info = NULL;
    unw_cursor_t cursor;
    int ret;
    size_t num_frames = 0;

    addr_space = unw_create_addr_space(&_UPT_accessors, 0);
    if (!addr_space) {
        printf("unw_create_addr_space failed.");
        goto done;
    }

    upt_info = (struct UPT_info*) _UPT_create(pid);
    if (!upt_info) {
        printf("Failed to create upt info.");
        goto done;
    }

    ret = unw_init_remote(&cursor, addr_space, upt_info);
    if (ret < 0) {
        printf("unw_init_remote failed %d", ret);
        goto done;
    }

    do {
        unw_word_t pc, sp;
        unw_word_t off = 0;
        char buf[512];

        ret = unw_get_reg(&cursor, UNW_REG_IP, &pc);
        if (ret < 0) {
            printf("Failed to read IP %d", ret);
            break;
        }
        ret = unw_get_reg(&cursor, UNW_REG_SP, &sp);
        if (ret < 0) {
            printf("Failed to read SP %d", ret);
            break;
        }
        if (unw_get_proc_name_by_ip(addr_space, pc, buf, sizeof(buf), &off, upt_info) >= 0
                && buf[0] != '\0') {
            printf("%p <%s + 0x%lx>\n", (void*) pc, buf, off);
        }

        num_frames++;
        ret = unw_step(&cursor);
    } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);

done:
    if (upt_info) {
        _UPT_destroy(upt_info);
    }
    if (addr_space) {
        unw_destroy_addr_space(addr_space);
    }
}

backtrace.h

#ifndef BACKTRACE_H_
#define BACKTRACE_H_

#include <sys/types.h>

void unwind(pid_t pid);

#endif /* BACKTRACE_H_ */