/* libunwind - a platform-independent unwind library

   Copyright (c) 2003-2005 Hewlett-Packard Development Company, L.P.

        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 "dwarf_i.h"

static inline int

is_cie_id (unw_word_t val, int is_debug_frame)

{

  /* The CIE ID is normally 0xffffffff (for 32-bit ELF) or

     0xffffffffffffffff (for 64-bit ELF).  However, .eh_frame

     uses 0.  */

  if (is_debug_frame)

      return (val == (uint32_t)(-1) || val == (uint64_t)(-1));

  else

    return (val == 0);

}

/* Note: we don't need to keep track of more than the first four

   characters of the augmentation string, because we (a) ignore any

   augmentation string contents once we find an unrecognized character

   and (b) those characters that we do recognize, can't be

   repeated.  */

static inline int

parse_cie (unw_addr_space_t as, unw_accessors_t *a, unw_word_t addr,

           const unw_proc_info_t *pi, struct dwarf_cie_info *dci,

           int is_debug_frame, void *arg)

{

  uint8_t version, ch, augstr[5], fde_encoding, handler_encoding;

  uint8_t address_size, segment_size;

  unw_word_t len, cie_end_addr, aug_size;

  uint32_t u32val;

  uint64_t u64val;

  size_t i;

  int ret;

# define STR2(x)        #x

# define STR(x)         STR2(x)

  /* Pick appropriate default for FDE-encoding.  DWARF spec says

     start-IP (initial_location) and the code-size (address_range) are

     "address-unit sized constants".  The `R' augmentation can be used

     to override this, but by default, we pick an address-sized unit

     for fde_encoding.  */

  switch (dwarf_addr_size (as))

    {

    case 4:     fde_encoding = DW_EH_PE_udata4; break;

    case 8:     fde_encoding = DW_EH_PE_udata8; break;

    default:    fde_encoding = DW_EH_PE_omit; break;

    }

  dci->lsda_encoding = DW_EH_PE_omit;

  dci->handler = 0;

  if ((ret = dwarf_readu32 (as, a, &addr, &u32val, arg)) < 0)

    return ret;

  if (u32val != 0xffffffff)

    {

      /* the CIE is in the 32-bit DWARF format */

      uint32_t cie_id;

      /* DWARF says CIE id should be 0xffffffff, but in .eh_frame, it's 0 */

      const uint32_t expected_id = (is_debug_frame) ? 0xffffffff : 0;

      len = u32val;

      cie_end_addr = addr + len;

      if ((ret = dwarf_readu32 (as, a, &addr, &cie_id, arg)) < 0)

        return ret;

      if (cie_id != expected_id)

        {

          Debug (1, "Unexpected CIE id %x\n", cie_id);

          return -UNW_EINVAL;

        }

    }

  else

    {

      /* the CIE is in the 64-bit DWARF format */

      uint64_t cie_id;

      /* DWARF says CIE id should be 0xffffffffffffffff, but in

         .eh_frame, it's 0 */

      const uint64_t expected_id = (is_debug_frame) ? 0xffffffffffffffffull : 0;

      if ((ret = dwarf_readu64 (as, a, &addr, &u64val, arg)) < 0)

        return ret;

      len = (unw_word_t) u64val;

      cie_end_addr = addr + len;

      if ((ret = dwarf_readu64 (as, a, &addr, &cie_id, arg)) < 0)

        return ret;

      if (cie_id != expected_id)

        {

          Debug (1, "Unexpected CIE id %llx\n", (long long) cie_id);

          return -UNW_EINVAL;

        }

    }

  dci->cie_instr_end = cie_end_addr;

  if ((ret = dwarf_readu8 (as, a, &addr, &version, arg)) < 0)

    return ret;

  /* GCC emits version 1??? */

  if (version != 1 && (version < DWARF_CIE_VERSION || version > DWARF_CIE_VERSION_MAX))

    {

      Debug (1, "Got CIE version %u, expected version 1 or between "

             STR (DWARF_CIE_VERSION) " and " STR (DWARF_CIE_VERSION_MAX) "\n", version);

      return -UNW_EBADVERSION;

    }

  /* read and parse the augmentation string: */

  memset (augstr, 0, sizeof (augstr));

  for (i = 0;;)

    {

      if ((ret = dwarf_readu8 (as, a, &addr, &ch, arg)) < 0)

        return ret;

      if (!ch)

        break;  /* end of augmentation string */

      if (i < sizeof (augstr) - 1)

        augstr[i++] = ch;

    }

  if (version > 3)

    {

      if((ret = dwarf_readu8(as, a, &addr, &address_size, arg)) < 0)

  return ret;

      if((ret = dwarf_readu8(as, a, &addr, &segment_size, arg)) < 0)

  return ret;

    }

  if ((ret = dwarf_read_uleb128 (as, a, &addr, &dci->code_align, arg)) < 0

      || (ret = dwarf_read_sleb128 (as, a, &addr, &dci->data_align, arg)) < 0)

    return ret;

  /* Read the return-address column either as a u8 or as a uleb128.  */

  if (version == 1)

    {

      if ((ret = dwarf_readu8 (as, a, &addr, &ch, arg)) < 0)

        return ret;

      dci->ret_addr_column = ch;

    }

  else if ((ret = dwarf_read_uleb128 (as, a, &addr, &dci->ret_addr_column,

                                      arg)) < 0)

    return ret;

  i = 0;

  if (augstr[0] == 'z')

    {

      dci->sized_augmentation = 1;

      if ((ret = dwarf_read_uleb128 (as, a, &addr, &aug_size, arg)) < 0)

        return ret;

      i++;

    }

  for (; i < sizeof (augstr) && augstr[i]; ++i)

    switch (augstr[i])

      {

      case 'L':

        /* read the LSDA pointer-encoding format.  */

        if ((ret = dwarf_readu8 (as, a, &addr, &ch, arg)) < 0)

          return ret;

        dci->lsda_encoding = ch;

        break;

      case 'R':

        /* read the FDE pointer-encoding format.  */

        if ((ret = dwarf_readu8 (as, a, &addr, &fde_encoding, arg)) < 0)

          return ret;

        break;

      case 'P':

        /* read the personality-routine pointer-encoding format.  */

        if ((ret = dwarf_readu8 (as, a, &addr, &handler_encoding, arg)) < 0)

          return ret;

        if ((ret = dwarf_read_encoded_pointer (as, a, &addr, handler_encoding,

                                               pi, &dci->handler, arg)) < 0)

          return ret;

        break;

      case 'S':

        /* This is a signal frame. */

        dci->signal_frame = 1;

        /* Temporarily set it to one so dwarf_parse_fde() knows that

           it should fetch the actual ABI/TAG pair from the FDE.  */

        dci->have_abi_marker = 1;

        break;

      default:

        Debug (1, "Unexpected augmentation string `%s'\n", augstr);

        if (dci->sized_augmentation)

          /* If we have the size of the augmentation body, we can skip

             over the parts that we don't understand, so we're OK. */

          goto done;

        else

          return -UNW_EINVAL;

      }

 done:

  dci->fde_encoding = fde_encoding;

  dci->cie_instr_start = addr;

  Debug (15, "CIE parsed OK, augmentation = \"%s\", handler=0x%lx\n",

         augstr, (long) dci->handler);

  return 0;

}

/* Extract proc-info from the FDE starting at address ADDR.

   Pass BASE as zero for eh_frame behaviour, or a pointer to

   debug_frame base for debug_frame behaviour.  */

HIDDEN int

dwarf_extract_proc_info_from_fde (unw_addr_space_t as, unw_accessors_t *a,

                                  unw_word_t *addrp, unw_proc_info_t *pi,

                                  unw_word_t base,

                                  int need_unwind_info, int is_debug_frame,

                                  void *arg)

{

  unw_word_t fde_end_addr, cie_addr, cie_offset_addr, aug_end_addr = 0;

  unw_word_t start_ip, ip_range, aug_size, addr = *addrp;

  int ret;

  uint8_t ip_range_encoding;

  struct dwarf_cie_info dci;

  uint64_t u64val;

  uint32_t u32val;

  Debug (12, "FDE @ 0x%lx\n", (long) addr);

  memset (&dci, 0, sizeof (dci));

  if ((ret = dwarf_readu32 (as, a, &addr, &u32val, arg)) < 0)

    return ret;

  if (u32val != 0xffffffff)

    {

      int32_t cie_offset = 0;

      /* In some configurations, an FDE with a 0 length indicates the

         end of the FDE-table.  */

      if (u32val == 0)

        return -UNW_ENOINFO;

      /* the FDE is in the 32-bit DWARF format */

      *addrp = fde_end_addr = addr + u32val;

      cie_offset_addr = addr;

      if ((ret = dwarf_reads32 (as, a, &addr, &cie_offset, arg)) < 0)

        return ret;

      if (is_cie_id (cie_offset, is_debug_frame))

        /* ignore CIEs (happens during linear searches) */

        return 0;

      if (is_debug_frame)

        cie_addr = base + cie_offset;

      else

        /* DWARF says that the CIE_pointer in the FDE is a

           .debug_frame-relative offset, but the GCC-generated .eh_frame

           sections instead store a "pcrelative" offset, which is just

           as fine as it's self-contained.  */

        cie_addr = cie_offset_addr - cie_offset;

    }

  else

    {

      int64_t cie_offset = 0;

      /* the FDE is in the 64-bit DWARF format */

      if ((ret = dwarf_readu64 (as, a, &addr, &u64val, arg)) < 0)

        return ret;

      *addrp = fde_end_addr = (unw_word_t) (addr + u64val);

      cie_offset_addr = addr;

      if ((ret = dwarf_reads64 (as, a, &addr, &cie_offset, arg)) < 0)

        return ret;

      if (is_cie_id ((unw_word_t) cie_offset, is_debug_frame))

        /* ignore CIEs (happens during linear searches) */

        return 0;

      if (is_debug_frame)

        cie_addr = (unw_word_t) (base + cie_offset);

      else

        /* DWARF says that the CIE_pointer in the FDE is a

           .debug_frame-relative offset, but the GCC-generated .eh_frame

           sections instead store a "pcrelative" offset, which is just

           as fine as it's self-contained.  */

        cie_addr = (unw_word_t) ((uint64_t) cie_offset_addr - cie_offset);

    }

  Debug (15, "looking for CIE at address %lx\n", (long) cie_addr);

  if ((ret = parse_cie (as, a, cie_addr, pi, &dci, is_debug_frame, arg)) < 0)

    return ret;

  /* IP-range has same encoding as FDE pointers, except that it's

     always an absolute value: */

  ip_range_encoding = dci.fde_encoding & DW_EH_PE_FORMAT_MASK;

  if ((ret = dwarf_read_encoded_pointer (as, a, &addr, dci.fde_encoding,

                                         pi, &start_ip, arg)) < 0

      || (ret = dwarf_read_encoded_pointer (as, a, &addr, ip_range_encoding,

                                            pi, &ip_range, arg)) < 0)

    return ret;

  pi->start_ip = start_ip;

  pi->end_ip = start_ip + ip_range;

  pi->handler = dci.handler;

  if (dci.sized_augmentation)

    {

      if ((ret = dwarf_read_uleb128 (as, a, &addr, &aug_size, arg)) < 0)

        return ret;

      aug_end_addr = addr + aug_size;

    }

  if ((ret = dwarf_read_encoded_pointer (as, a, &addr, dci.lsda_encoding,

                                         pi, &pi->lsda, arg)) < 0)

    return ret;

  Debug (15, "FDE covers IP 0x%lx-0x%lx, LSDA=0x%lx\n",

         (long) pi->start_ip, (long) pi->end_ip, (long) pi->lsda);

  if (need_unwind_info)

    {

      pi->format = UNW_INFO_FORMAT_TABLE;

      pi->unwind_info_size = sizeof (dci);

      pi->unwind_info = mempool_alloc (&dwarf_cie_info_pool);

      if (!pi->unwind_info)

        return -UNW_ENOMEM;

      if (dci.have_abi_marker)

        {

          if ((ret = dwarf_readu16 (as, a, &addr, &dci.abi, arg)) < 0

              || (ret = dwarf_readu16 (as, a, &addr, &dci.tag, arg)) < 0)

            return ret;

          Debug (13, "Found ABI marker = (abi=%u, tag=%u)\n",

                 dci.abi, dci.tag);

        }

      if (dci.sized_augmentation)

        dci.fde_instr_start = aug_end_addr;

      else

        dci.fde_instr_start = addr;

      dci.fde_instr_end = fde_end_addr;

      memcpy (pi->unwind_info, &dci, sizeof (dci));

    }

  return 0;

}