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

static void full_write(int fd, const char *buf, size_t len) {
  while (len > 0) {
    ssize_t ret = write(fd, buf, len);

    if ((ret == -1) && (errno != EINTR))
      break;

    buf += (size_t)ret;
    len -= (size_t)ret;
  }
}

void print_backtrace() {
  static const char start[] = "BACKTRACE ------------\n";
  static const char end[] = "----------------------\n";

  void *bt[1024];
  int bt_size;
  char **bt_syms;
  int i;

  bt_size = backtrace(bt, 1024);
  bt_syms = backtrace_symbols(bt, bt_size);
  full_write(STDERR_FILENO, start, strlen(start));
  for (i = 1; i < bt_size; i++) {
    size_t len = strlen(bt_syms[i]);
    full_write(STDERR_FILENO, bt_syms[i], len);
    full_write(STDERR_FILENO, "\n", 1);
  }
  full_write(STDERR_FILENO, end, strlen(end));
  free(bt_syms);
}