print stack trace when crashing

[igaw]

In case the library or nvme-cl crashes it would really help to get a stack trace.

Here two simple examples.

#define _GNU_SOURCE
#include <execinfo.h>
#include <stdio.h>
#include <stdlib.h>

void print_stacktrace(void)
{
    void *buffer[64];
    int nptrs = backtrace(buffer, 64);

    printf("Stack trace (%d frames):\n", nptrs);

    char **symbols = backtrace_symbols(buffer, nptrs);
    if (!symbols) {
        perror("backtrace_symbols");
        exit(EXIT_FAILURE);
    }

    for (int i = 0; i < nptrs; i++)
        printf("  %s\n", symbols[i]);

    free(symbols);
}

void foo(void) { print_stacktrace(); }
void bar(void) { foo(); }

int main(void)
{
    bar();
    return 0;
}

$ gcc -g -rdynamic stacktrace.c -o stacktrace
$ ./stacktrace
Stack trace (7 frames):
  ./stacktrace(print_stacktrace+0x1f) [0x4004d5]
  ./stacktrace(foo+0x9) [0x400575]
  ./stacktrace(bar+0x9) [0x400581]
  ./stacktrace(main+0x9) [0x40058d]
  /lib64/libc.so.6(+0x35b5) [0x7fa9106355b5]
  /lib64/libc.so.6(__libc_start_main+0x88) [0x7fa910635668]
  ./stacktrace(_start+0x25) [0x4003f5]

#include <libunwind.h>
#include <stdio.h>

void print_stacktrace(void)
{
    unw_cursor_t cursor;
    unw_context_t context;

    unw_getcontext(&context);
    unw_init_local(&cursor, &context);

    printf("Stack trace:\n");
    while (unw_step(&cursor) > 0) {
        unw_word_t offset, pc;
        char func[256];

        unw_get_reg(&cursor, UNW_REG_IP, &pc);
        printf("  0x%lx: ", (long) pc);

        if (!unw_get_proc_name(&cursor, func, sizeof(func), &offset))
            printf("%s + 0x%lx\n", func, (long) offset);
        else
            printf("?\n");
    }
}

void foo(void) { print_stacktrace(); }
void bar(void) { foo(); }

int main(void)
{
    bar();
    return 0;
}

$ gcc -g stacktrace.c -lunwind -lunwind-x86_64 -o stacktrace
$ ./stacktrace
Stack trace:
  0x4005b8: foo + 0x9
  0x4005c4: bar + 0x9
  0x4005d0: main + 0x9
  0x7fee978de5b5: __libc_start_call_main + 0x75
  0x7fee978de668: __libc_start_main + 0x88
  0x400405: _start + 0x25