/* libunwind - a platform-independent unwind library

   Copyright (C) 2003-2005 Hewlett-Packard Co

        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>

This file is part of libunwind.

Permission is hereby granted, free of charge, to any person obtaining

a copy of this software and associated documentation files (the

"Software"), to deal in the Software without restriction, including

without limitation the rights to use, copy, modify, merge, publish,

distribute, sublicense, and/or sell copies of the Software, and to

permit persons to whom the Software is furnished to do so, subject to

the following conditions:

The above copyright notice and this permission notice shall be

included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE

LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */

#include <limits.h>

#include <stdio.h>

#include <sys/stat.h>

#include <string.h>

#include <stdlib.h>

#include <assert.h>

#include "libunwind_i.h"

#include "os-linux.h"

#ifndef MAX_VDSO_SIZE

/*Dont know what is the Max Size in my system it was 8192 or twice the page size*/

# define MAX_VDSO_SIZE ((size_t) 2 * sysconf (_SC_PAGESIZE))

#endif

#ifndef MAP_32BIT

# define MAP_32BIT 0

#endif

int

tdep_get_elf_image (unw_addr_space_t as, struct elf_image *ei, pid_t pid, unw_word_t ip,

                    unsigned long *segbase, unsigned long *mapoff,

                    char *path, size_t pathlen,

                    void *arg)

{

  struct map_iterator mi;

  int found = 0, rc = UNW_ESUCCESS;

  unsigned long hi;

  char root[sizeof ("/proc/0123456789/root")], *cp;

  char *full_path;

  struct stat st;

  unw_accessors_t *a;

  unw_word_t magic;

  if (maps_init (&mi, pid) < 0)

    return -1;

  while (maps_next (&mi, segbase, &hi, mapoff, NULL))

    if (ip >= *segbase && ip < hi)

      {

        found = 1;

        break;

      }

  if (!found)

    {

      maps_close (&mi);

      return -1;

    }

  // get path only, no need to map elf image

  if (!ei && path)

    {

      strncpy(path, mi.path, pathlen);

      path[pathlen - 1] = '\0';

      if (strlen(mi.path) >= pathlen)

        rc = -UNW_ENOMEM;

      maps_close (&mi);

      return rc;

    }

  full_path = mi.path;

  /* Get process root */

  memcpy (root, "/proc/", 6);

  cp = unw_ltoa (root + 6, pid);

  assert (cp + 6 < root + sizeof (root));

  memcpy (cp, "/root", 6);

  size_t _len = strlen (mi.path) + 1;

  if (!stat(root, &st) && S_ISDIR(st.st_mode))

    _len += strlen (root);

  else

    root[0] = '\0';

  full_path = path;

  if(!path)

    full_path = (char*) malloc (_len);

  else if(_len >= pathlen) // passed buffer is too small, fail

    {

      maps_close (&mi);

      return -1;

    }

  strcpy (full_path, root);

  strcat (full_path, mi.path);

  if (stat(full_path, &st) || !S_ISREG(st.st_mode))

    strcpy(full_path, mi.path);

  rc = elf_map_image (ei, full_path);

  /*Follwing code is adapted from 

    https://sourceware.org/pipermail/frysk-cvs/2008q1/007245.html,

    For VDSO there is no file in the file system, so read the ELF , 

    and create mmaped file for the content of the VDSO 

  */

  if (rc != -1)

  {

    maps_close (&mi);

    goto err_exit;

  }

  /* If the above failed, try to bring in page-sized segments directly

     from process memory.  This enables us to locate VDSO unwind

     tables.  */

  ei->size = hi - *segbase;

  if (ei->size > MAX_VDSO_SIZE) 

  {

    maps_close (&mi);

    goto err_exit;

  }

  a = unw_get_accessors (as);

  if (! a->access_mem) 

  {

    maps_close (&mi);

    goto err_exit;

  }

  /* Try to decide whether it's an ELF image before bringing it all

     in.  */

  if (ei->size <= EI_CLASS || ei->size <= sizeof (magic))

  {

    maps_close (&mi);

    goto err_exit;

  }

  if (sizeof (magic) >= SELFMAG)

    {

      int ret = (*a->access_mem) (as, *segbase, &magic, 0, arg);

      if (ret < 0)

      {

        rc = ret;

        maps_close (&mi);

        goto err_exit;

      }

      if (memcmp (&magic, ELFMAG, SELFMAG) != 0)

      {

        maps_close (&mi);

        goto err_exit;

      }

    }

  ei->image = mmap (0, ei->size, PROT_READ | PROT_WRITE,

           MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);

  if (ei->image == MAP_FAILED)

    {

      maps_close (&mi);

      goto err_exit;

    }

  if (sizeof (magic) >= SELFMAG)

    {

      *(unw_word_t *)ei->image = magic;

      hi = sizeof (magic);

    }

  else

    hi = 0;

  for (; hi < ei->size; hi += sizeof (unw_word_t))

    {

      rc = (*a->access_mem) (as, *segbase + hi, ei->image + hi,

               0, arg);

      if (rc < 0)

   {

     munmap (ei->image, ei->size);

     maps_close (&mi);

     goto err_exit;

   }

    }

  if (*segbase == *mapoff

      && (*path == 0 || strcmp (path, "[vdso]") == 0))

    *mapoff = 0;

err_exit:

  if (!path)

    free (full_path);

  maps_close (&mi);

  return rc;

}

#ifndef UNW_REMOTE_ONLY

void

tdep_get_exe_image_path (char *path)

{

  strcpy(path, "/proc/self/exe");

}

#endif /* !UNW_REMOTE_ONLY */