/*-

 * Copyright (c) 2006 Verdens Gang AS

 * Copyright (c) 2006-2022 Varnish Software AS

 * All rights reserved.

 *

 * Author: Poul-Henning Kamp <phk@phk.freebsd.dk>

 * Author: Guillaume Quintard <guillaume@varnish-software.com>

 * Author: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 * We tend to print back-traces when there is a fatal error, so the VBT code

 * should avoid assertions.

 */

#include "config.h"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#ifdef WITH_UNWIND

#  include <libunwind.h>

#endif

#ifdef HAVE_EXECINFO_H

#  include <execinfo.h>

#endif

#include "vdef.h"

#include "vas.h"

#include "vbt.h"

#include "vsb.h"

#include "miniobj.h"

#ifdef WITH_UNWIND

static int

vbt_unwind(struct vsb *vsb)

{

  unw_cursor_t cursor; unw_context_t uc;

  unw_word_t ip, sp;

  unw_word_t offp;

  char fname[1024];

  const char *sep;

  int ret;

  ret = unw_getcontext(&uc);

  if (ret != 0) {

    VSB_printf(vsb, "Backtrace not available "

        "(unw_getcontext returned %d)\n", ret);

    return (-1);

  }

  ret = unw_init_local(&cursor, &uc);

  if (ret != 0) {

    VSB_printf(vsb, "Backtrace not available "

        "(unw_init_local returned %d)\n", ret);

    return (-1);

  }

  while (unw_step(&cursor) > 0) {

    fname[0] = '\0';

    sep = "";

    if (!unw_get_reg(&cursor, UNW_REG_IP, &ip)) {

      VSB_printf(vsb, "ip=0x%lx", (long) ip);

      sep = " ";

    }

    if (!unw_get_reg(&cursor, UNW_REG_SP, &sp)) {

      VSB_printf(vsb, "%ssp=0x%lx", sep, (long) sp);

      sep = " ";

    }

    if (!unw_get_proc_name(&cursor, fname, sizeof(fname), &offp)) {

      VSB_printf(vsb, "%s<%s+0x%lx>",

          sep, fname[0] ? fname : "<unknown>", (long)offp);

    }

    VSB_putc(vsb, '\n');

  }

  return (0);

}

#endif

#ifdef HAVE_EXECINFO_H

#  define BACKTRACE_LEVELS  20

static void

vbt_execinfo(struct vsb *vsb)

{

  void *array[BACKTRACE_LEVELS];

  size_t size;

  size_t i;

  char **strings;

  char *p;

  char buf[32];

  size = backtrace (array, BACKTRACE_LEVELS);

  if (size > BACKTRACE_LEVELS) {

    VSB_printf(vsb, "Backtrace not available (ret=%zu)\n", size);

    return;

  }

  for (i = 0; i < size; i++) {

    bprintf(buf, "%p", array[i]);

    VSB_printf(vsb, "%s: ", buf);

    strings = backtrace_symbols(&array[i], 1);

    if (strings == NULL || strings[0] == NULL) {

      VSB_cat(vsb, "(?)");

    } else {

      p = strings[0];

      if (!memcmp(buf, p, strlen(buf))) {

        p += strlen(buf);

        if (*p == ':')

          p++;

        while (*p == ' ')

          p++;

      }

      VSB_cat(vsb, p);

    }

    VSB_cat(vsb, "\n");

    free(strings);

  }

}

#endif

void

VBT_format(struct vsb *vsb)

{

  if (!VALID_OBJ(vsb, VSB_MAGIC))

    return;

#ifdef WITH_UNWIND

  if (!vbt_unwind(vsb))

    return;

#  ifdef HAVE_EXECINFO_H

  VSB_cat(vsb, "Falling back to execinfo backtrace\n");

#  endif

#endif

#ifdef HAVE_EXECINFO_H

  vbt_execinfo(vsb);

#endif

}

int

VBT_dump(size_t len, char buf[len])

{

  struct vsb vsb[1];

  if (VSB_init(vsb, buf, len) == NULL)

    return (-1);

  VSB_printf(vsb, "Backtrace:\n");

  VSB_indent(vsb, 2);

  VBT_format(vsb);

  VSB_indent(vsb, -2);

  return (0);

}