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/* Handle Darwin shared libraries for GDB, the GNU Debugger.

   Copyright (C) 2009, 2010 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "symtab.h"

#include "bfd.h"

#include "symfile.h"

#include "objfiles.h"

#include "gdbcore.h"

#include "target.h"

#include "inferior.h"

#include "regcache.h"

#include "gdbthread.h"

#include "gdb_assert.h"

#include "solist.h"

#include "solib.h"

#include "solib-svr4.h"

#include "bfd-target.h"

#include "elf-bfd.h"

#include "exec.h"

#include "auxv.h"

#include "exceptions.h"

#include "mach-o.h"

struct gdb_dyld_image_info

{

  /* Base address (which corresponds to the Mach-O header).  */

  CORE_ADDR mach_header;

  /* Image file path.  */

  CORE_ADDR file_path;

  /* st.m_time of image file.  */

  unsigned long mtime;

};

/* Content of inferior dyld_all_image_infos structure.

   See /usr/include/mach-o/dyld_images.h for the documentation.  */

struct gdb_dyld_all_image_infos

{

  /* Version (1).  */

  unsigned int version;

  /* Number of images.  */

  unsigned int count;

  /* Image description.  */

  CORE_ADDR info;

  /* Notifier (function called when a library is added or removed).  */

  CORE_ADDR notifier;

};

/* Current all_image_infos version.  */

#define DYLD_VERSION_MIN 1

#define DYLD_VERSION_MAX 7

/* Address of structure dyld_all_image_infos in inferior.  */

static CORE_ADDR dyld_all_image_addr;

/* Gdb copy of dyld_all_info_infos.  */

static struct gdb_dyld_all_image_infos dyld_all_image;

/* Return non-zero if the version in dyld_all_image is known.  */

static int

darwin_dyld_version_ok (void)

{

  return dyld_all_image.version >= DYLD_VERSION_MIN

    && dyld_all_image.version <= DYLD_VERSION_MAX;

}

/* Read dyld_all_image from inferior.  */

static void

darwin_load_image_infos (void)

{

  gdb_byte buf[24];

  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);

  struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;

  int len;

  /* If the structure address is not known, don't continue.  */

  if (dyld_all_image_addr == 0)

    return;

  /* The structure has 4 fields: version (4 bytes), count (4 bytes),

     info (pointer) and notifier (pointer).  */

  len = 4 + 4 + 2 * ptr_type->length;

  gdb_assert (len <= sizeof (buf));

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

  /* Read structure raw bytes from target.  */

  if (target_read_memory (dyld_all_image_addr, buf, len))

    return;

  /* Extract the fields.  */

  dyld_all_image.version = extract_unsigned_integer (buf, 4, byte_order);

  if (!darwin_dyld_version_ok ())

    return;

  dyld_all_image.count = extract_unsigned_integer (buf + 4, 4, byte_order);

  dyld_all_image.info = extract_typed_address (buf + 8, ptr_type);

  dyld_all_image.notifier = extract_typed_address

    (buf + 8 + ptr_type->length, ptr_type);

}

/* Link map info to include in an allocated so_list entry.  */

struct lm_info

{

  /* The target location of lm.  */

  CORE_ADDR lm_addr;

};

struct darwin_so_list

{

  /* Common field.  */

  struct so_list sl;

  /* Darwin specific data.  */

  struct lm_info li;

};

/* Lookup the value for a specific symbol.  */

static CORE_ADDR

lookup_symbol_from_bfd (bfd *abfd, char *symname)

{

  long storage_needed;

  asymbol **symbol_table;

  unsigned int number_of_symbols;

  unsigned int i;

  CORE_ADDR symaddr = 0;

  storage_needed = bfd_get_symtab_upper_bound (abfd);

  if (storage_needed <= 0)

    return 0;

  symbol_table = (asymbol **) xmalloc (storage_needed);

  number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);

  for (i = 0; i < number_of_symbols; i++)

    {

      asymbol *sym = symbol_table[i];

      if (strcmp (sym->name, symname) == 0

          && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)

        {

          /* BFD symbols are section relative.  */

          symaddr = sym->value + sym->section->vma;

          break;

        }

    }

  xfree (symbol_table);

  return symaddr;

}

/* Return program interpreter string.  */

static gdb_byte *

find_program_interpreter (void)

{

  gdb_byte *buf = NULL;

  /* If we have an exec_bfd, get the interpreter from the load commands.  */

  if (exec_bfd)

    {

      bfd_mach_o_load_command *cmd;

      if (bfd_mach_o_lookup_command (exec_bfd,

                                     BFD_MACH_O_LC_LOAD_DYLINKER, &cmd) == 1)

        return cmd->command.dylinker.name_str;

    }

  /* If we didn't find it, read from memory.

     FIXME: todo.  */

  return buf;

}

/*  Not used.  I don't see how the main symbol file can be found: the

    interpreter name is needed and it is known from the executable file.

    Note that darwin-nat.c implements pid_to_exec_file.  */

static int

open_symbol_file_object (void *from_ttyp)

{

  return 0;

}

/* Build a list of currently loaded shared objects.  See solib-svr4.c  */

static struct so_list *

darwin_current_sos (void)

{

  struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;

  int ptr_len = TYPE_LENGTH (ptr_type);

  unsigned int image_info_size;

  CORE_ADDR lm;

  struct so_list *head = NULL;

  struct so_list *tail = NULL;

  int i;

  /* Be sure image infos are loaded.  */

  darwin_load_image_infos ();

  if (!darwin_dyld_version_ok ())

    return NULL;

  image_info_size = ptr_len * 3;

  /* Read infos for each solib.

     This first entry is ignored as this is the executable itself.  */

  for (i = 1; i < dyld_all_image.count; i++)

    {

      CORE_ADDR info = dyld_all_image.info + i * image_info_size;

      char buf[image_info_size];

      CORE_ADDR load_addr;

      CORE_ADDR path_addr;

      char *file_path;

      int errcode;

      struct darwin_so_list *dnew;

      struct so_list *new;

      struct cleanup *old_chain;

      /* Read image info from inferior.  */

      if (target_read_memory (info, buf, image_info_size))

        break;

      load_addr = extract_typed_address (buf, ptr_type);

      path_addr = extract_typed_address (buf + ptr_len, ptr_type);

      target_read_string (path_addr, &file_path,

                          SO_NAME_MAX_PATH_SIZE - 1, &errcode);

      if (errcode)

        break;

      /* Create and fill the new so_list element.  */

      dnew = XZALLOC (struct darwin_so_list);

      new = &dnew->sl;

      old_chain = make_cleanup (xfree, dnew);

      new->lm_info = &dnew->li;

      strncpy (new->so_name, file_path, SO_NAME_MAX_PATH_SIZE - 1);

      new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';

      strcpy (new->so_original_name, new->so_name);

      xfree (file_path);

      new->lm_info->lm_addr = load_addr;

      if (head == NULL)

        head = new;

      else

        tail->next = new;

      tail = new;

      discard_cleanups (old_chain);

    }

  return head;

}

/* Return 1 if PC lies in the dynamic symbol resolution code of the

   run time loader.  */

int

darwin_in_dynsym_resolve_code (CORE_ADDR pc)

{

  return 0;

}

/* No special symbol handling.  */

static void

darwin_special_symbol_handling (void)

{

}

/* Shared library startup support.  See documentation in solib-svr4.c  */

static void

darwin_solib_create_inferior_hook (int from_tty)

{

  struct minimal_symbol *msymbol;

  char **bkpt_namep;

  asection *interp_sect;

  gdb_byte *interp_name;

  CORE_ADDR sym_addr;

  CORE_ADDR load_addr = 0;

  int load_addr_found = 0;

  int loader_found_in_list = 0;

  struct so_list *so;

  bfd *dyld_bfd = NULL;

  struct inferior *inf = current_inferior ();

  /* First, remove all the solib event breakpoints.  Their addresses

     may have changed since the last time we ran the program.  */

  remove_solib_event_breakpoints ();

  /* Find the program interpreter.  */

  interp_name = find_program_interpreter ();

  if (!interp_name)

    return;

  /* Create a bfd for the interpreter.  */

  sym_addr = 0;

  dyld_bfd = bfd_openr (interp_name, gnutarget);

  if (dyld_bfd)

    {

      bfd *sub;

      sub = bfd_mach_o_fat_extract (dyld_bfd, bfd_object,

                                    gdbarch_bfd_arch_info (target_gdbarch));

      if (sub)

        dyld_bfd = sub;

      else

        {

          bfd_close (dyld_bfd);

          dyld_bfd = NULL;

        }

    }

  if (!dyld_bfd)

    return;

  if (!inf->attach_flag)

    {

      /* We find the dynamic linker's base address by examining

         the current pc (which should point at the entry point for the

         dynamic linker) and subtracting the offset of the entry point.  */

      load_addr = (regcache_read_pc (get_current_regcache ())

                   - bfd_get_start_address (dyld_bfd));

    }

  else

    {

      /* FIXME: todo.

         Get address of __DATA.__dyld in exec_bfd, read address at offset 0.

      */

      return;

    }

  /* Now try to set a breakpoint in the dynamic linker.  */

  dyld_all_image_addr =

    lookup_symbol_from_bfd (dyld_bfd, "_dyld_all_image_infos");

  bfd_close (dyld_bfd);

  if (dyld_all_image_addr == 0)

    return;

  dyld_all_image_addr += load_addr;

  darwin_load_image_infos ();

  if (darwin_dyld_version_ok ())

    create_solib_event_breakpoint (target_gdbarch, dyld_all_image.notifier);

}

static void

darwin_clear_solib (void)

{

  dyld_all_image_addr = 0;

  dyld_all_image.version = 0;

}

static void

darwin_free_so (struct so_list *so)

{

}

/* The section table is built from bfd sections using bfd VMAs.

   Relocate these VMAs according to solib info.  */

static void

darwin_relocate_section_addresses (struct so_list *so,

                                   struct target_section *sec)

{

  sec->addr += so->lm_info->lm_addr;

  sec->endaddr += so->lm_info->lm_addr;

  /* Best effort to set addr_high/addr_low.  This is used only by

     'info sharedlibary'.  */

  if (so->addr_high == 0)

    {

      so->addr_low = sec->addr;

      so->addr_high = sec->endaddr;

    }

  if (sec->endaddr > so->addr_high)

    so->addr_high = sec->endaddr;

  if (sec->addr < so->addr_low)

    so->addr_low = sec->addr;

}

static struct symbol *

darwin_lookup_lib_symbol (const struct objfile *objfile,

                          const char *name,

                          const char *linkage_name,

                          const domain_enum domain)

{

  return NULL;

}

static bfd *

darwin_bfd_open (char *pathname)

{

  char *found_pathname;

  int found_file;

  bfd *abfd;

  bfd *res;

  /* Search for shared library file.  */

  found_pathname = solib_find (pathname, &found_file);

  if (found_pathname == NULL)

    perror_with_name (pathname);

  /* Open bfd for shared library.  */

  abfd = solib_bfd_fopen (found_pathname, found_file);

  res = bfd_mach_o_fat_extract (abfd, bfd_object,

                                gdbarch_bfd_arch_info (target_gdbarch));

  if (!res)

    {

      bfd_close (abfd);

      make_cleanup (xfree, found_pathname);

      error (_("`%s': not a shared-library: %s"),

             found_pathname, bfd_errmsg (bfd_get_error ()));

    }

  return res;

}

struct target_so_ops darwin_so_ops;

void

_initialize_darwin_solib (void)

{

  darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses;

  darwin_so_ops.free_so = darwin_free_so;

  darwin_so_ops.clear_solib = darwin_clear_solib;

  darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook;

  darwin_so_ops.special_symbol_handling = darwin_special_symbol_handling;

  darwin_so_ops.current_sos = darwin_current_sos;

  darwin_so_ops.open_symbol_file_object = open_symbol_file_object;

  darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;

  darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;

  darwin_so_ops.bfd_open = darwin_bfd_open;

}