Subversion Repositories openrisc_2011-10-31

/* Shared library support for IRIX.

   Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2004,

   2007, 2008, 2009, 2010 Free Software Foundation, Inc.

   This file was created using portions of irix5-nat.c originally

   contributed to GDB by Ian Lance Taylor.

   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"

/* FIXME: ezannoni/2004-02-13 Verify that the include below is

   really needed.  */

#include "symfile.h"

#include "objfiles.h"

#include "gdbcore.h"

#include "target.h"

#include "inferior.h"

#include "gdbthread.h"

#include "solist.h"

#include "solib.h"

#include "solib-irix.h"

/* Link map info to include in an allocate so_list entry.  Unlike some

   of the other solib backends, this (Irix) backend chooses to decode

   the link map info obtained from the target and store it as (mostly)

   CORE_ADDRs which need no further decoding.  This is more convenient

   because there are three different link map formats to worry about.

   We use a single routine (fetch_lm_info) to read (and decode) the target

   specific link map data.  */

struct lm_info

{

  CORE_ADDR addr;               /* address of obj_info or obj_list

                                   struct on target (from which the

                                   following information is obtained).  */

  CORE_ADDR next;               /* address of next item in list.  */

  CORE_ADDR reloc_offset;       /* amount to relocate by  */

  CORE_ADDR pathname_addr;      /* address of pathname  */

  int pathname_len;             /* length of pathname */

};

/* It's not desirable to use the system header files to obtain the

   structure of the obj_list or obj_info structs.  Therefore, we use a

   platform neutral representation which has been derived from the IRIX

   header files.  */

typedef struct

{

  gdb_byte b[4];

}

gdb_int32_bytes;

typedef struct

{

  gdb_byte b[8];

}

gdb_int64_bytes;

/* The "old" obj_list struct.  This is used with old (o32) binaries.

   The ``data'' member points at a much larger and more complicated

   struct which we will only refer to by offsets.  See

   fetch_lm_info().  */

struct irix_obj_list

{

  gdb_int32_bytes data;

  gdb_int32_bytes next;

  gdb_int32_bytes prev;

};

/* The ELF32 and ELF64 versions of the above struct.  The oi_magic value

   corresponds to the ``data'' value in the "old" struct.  When this value

   is 0xffffffff, the data will be in one of the following formats.  The

   ``oi_size'' field is used to decide which one we actually have.  */

struct irix_elf32_obj_info

{

  gdb_int32_bytes oi_magic;

  gdb_int32_bytes oi_size;

  gdb_int32_bytes oi_next;

  gdb_int32_bytes oi_prev;

  gdb_int32_bytes oi_ehdr;

  gdb_int32_bytes oi_orig_ehdr;

  gdb_int32_bytes oi_pathname;

  gdb_int32_bytes oi_pathname_len;

};

struct irix_elf64_obj_info

{

  gdb_int32_bytes oi_magic;

  gdb_int32_bytes oi_size;

  gdb_int64_bytes oi_next;

  gdb_int64_bytes oi_prev;

  gdb_int64_bytes oi_ehdr;

  gdb_int64_bytes oi_orig_ehdr;

  gdb_int64_bytes oi_pathname;

  gdb_int32_bytes oi_pathname_len;

  gdb_int32_bytes padding;

};

/* Union of all of the above (plus a split out magic field).  */

union irix_obj_info

{

  gdb_int32_bytes magic;

  struct irix_obj_list ol32;

  struct irix_elf32_obj_info oi32;

  struct irix_elf64_obj_info oi64;

};

/* MIPS sign extends its 32 bit addresses.  We could conceivably use

   extract_typed_address here, but to do so, we'd have to construct an

   appropriate type.  Calling extract_signed_integer seems simpler.  */

static CORE_ADDR

extract_mips_address (void *addr, int len, enum bfd_endian byte_order)

{

  return extract_signed_integer (addr, len, byte_order);

}

/* Fetch and return the link map data associated with ADDR.  Note that

   this routine automatically determines which (of three) link map

   formats is in use by the target.  */

static struct lm_info

fetch_lm_info (CORE_ADDR addr)

{

  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);

  struct lm_info li;

  union irix_obj_info buf;

  li.addr = addr;

  /* The smallest region that we'll need is for buf.ol32.  We'll read

     that first.  We'll read more of the buffer later if we have to deal

     with one of the other cases.  (We don't want to incur a memory error

     if we were to read a larger region that generates an error due to

     being at the end of a page or the like.)  */

  read_memory (addr, (char *) &buf, sizeof (buf.ol32));

  if (extract_unsigned_integer (buf.magic.b, sizeof (buf.magic), byte_order)

      != 0xffffffff)

    {

      /* Use buf.ol32... */

      char obj_buf[432];

      CORE_ADDR obj_addr = extract_mips_address (&buf.ol32.data,

                                                 sizeof (buf.ol32.data),

                                                 byte_order);

      li.next = extract_mips_address (&buf.ol32.next,

                                      sizeof (buf.ol32.next), byte_order);

      read_memory (obj_addr, obj_buf, sizeof (obj_buf));

      li.pathname_addr = extract_mips_address (&obj_buf[236], 4, byte_order);

      li.pathname_len = 0;       /* unknown */

      li.reloc_offset = extract_mips_address (&obj_buf[196], 4, byte_order)

        - extract_mips_address (&obj_buf[248], 4, byte_order);

    }

  else if (extract_unsigned_integer (buf.oi32.oi_size.b,

                                     sizeof (buf.oi32.oi_size), byte_order)

           == sizeof (buf.oi32))

    {

      /* Use buf.oi32...  */

      /* Read rest of buffer.  */

      read_memory (addr + sizeof (buf.ol32),

                   ((char *) &buf) + sizeof (buf.ol32),

                   sizeof (buf.oi32) - sizeof (buf.ol32));

      /* Fill in fields using buffer contents.  */

      li.next = extract_mips_address (&buf.oi32.oi_next,

                                      sizeof (buf.oi32.oi_next), byte_order);

      li.reloc_offset = extract_mips_address (&buf.oi32.oi_ehdr,

                                              sizeof (buf.oi32.oi_ehdr),

                                              byte_order)

        - extract_mips_address (&buf.oi32.oi_orig_ehdr,

                                sizeof (buf.oi32.oi_orig_ehdr), byte_order);

      li.pathname_addr = extract_mips_address (&buf.oi32.oi_pathname,

                                               sizeof (buf.oi32.oi_pathname),

                                               byte_order);

      li.pathname_len = extract_unsigned_integer (buf.oi32.oi_pathname_len.b,

                                                  sizeof (buf.oi32.

                                                          oi_pathname_len),

                                                  byte_order);

    }

  else if (extract_unsigned_integer (buf.oi64.oi_size.b,

                                     sizeof (buf.oi64.oi_size), byte_order)

           == sizeof (buf.oi64))

    {

      /* Use buf.oi64...  */

      /* Read rest of buffer.  */

      read_memory (addr + sizeof (buf.ol32),

                   ((char *) &buf) + sizeof (buf.ol32),

                   sizeof (buf.oi64) - sizeof (buf.ol32));

      /* Fill in fields using buffer contents.  */

      li.next = extract_mips_address (&buf.oi64.oi_next,

                                      sizeof (buf.oi64.oi_next), byte_order);

      li.reloc_offset = extract_mips_address (&buf.oi64.oi_ehdr,

                                              sizeof (buf.oi64.oi_ehdr),

                                              byte_order)

        - extract_mips_address (&buf.oi64.oi_orig_ehdr,

                                sizeof (buf.oi64.oi_orig_ehdr), byte_order);

      li.pathname_addr = extract_mips_address (&buf.oi64.oi_pathname,

                                               sizeof (buf.oi64.oi_pathname),

                                               byte_order);

      li.pathname_len = extract_unsigned_integer (buf.oi64.oi_pathname_len.b,

                                                  sizeof (buf.oi64.

                                                          oi_pathname_len),

                                                  byte_order);

    }

  else

    {

      error (_("Unable to fetch shared library obj_info or obj_list info."));

    }

  return li;

}

/* The symbol which starts off the list of shared libraries.  */

#define DEBUG_BASE "__rld_obj_head"

static void *base_breakpoint;

static CORE_ADDR debug_base;    /* Base of dynamic linker structures */

/*

   LOCAL FUNCTION

   locate_base -- locate the base address of dynamic linker structs

   SYNOPSIS

   CORE_ADDR locate_base (void)

   DESCRIPTION

   For both the SunOS and SVR4 shared library implementations, if the

   inferior executable has been linked dynamically, there is a single

   address somewhere in the inferior's data space which is the key to

   locating all of the dynamic linker's runtime structures.  This

   address is the value of the symbol defined by the macro DEBUG_BASE.

   The job of this function is to find and return that address, or to

   return 0 if there is no such address (the executable is statically

   linked for example).

   For SunOS, the job is almost trivial, since the dynamic linker and

   all of it's structures are statically linked to the executable at

   link time.  Thus the symbol for the address we are looking for has

   already been added to the minimal symbol table for the executable's

   objfile at the time the symbol file's symbols were read, and all we

   have to do is look it up there.  Note that we explicitly do NOT want

   to find the copies in the shared library.

   The SVR4 version is much more complicated because the dynamic linker

   and it's structures are located in the shared C library, which gets

   run as the executable's "interpreter" by the kernel.  We have to go

   to a lot more work to discover the address of DEBUG_BASE.  Because

   of this complexity, we cache the value we find and return that value

   on subsequent invocations.  Note there is no copy in the executable

   symbol tables.

   Irix 5 is basically like SunOS.

   Note that we can assume nothing about the process state at the time

   we need to find this address.  We may be stopped on the first instruc-

   tion of the interpreter (C shared library), the first instruction of

   the executable itself, or somewhere else entirely (if we attached

   to the process for example).

 */

static CORE_ADDR

locate_base (void)

{

  struct minimal_symbol *msymbol;

  CORE_ADDR address = 0;

  msymbol = lookup_minimal_symbol (DEBUG_BASE, NULL, symfile_objfile);

  if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))

    {

      address = SYMBOL_VALUE_ADDRESS (msymbol);

    }

  return (address);

}

/*

   LOCAL FUNCTION

   disable_break -- remove the "mapping changed" breakpoint

   SYNOPSIS

   static int disable_break ()

   DESCRIPTION

   Removes the breakpoint that gets hit when the dynamic linker

   completes a mapping change.

 */

static int

disable_break (void)

{

  int status = 1;

  /* Note that breakpoint address and original contents are in our address

     space, so we just need to write the original contents back. */

  if (deprecated_remove_raw_breakpoint (target_gdbarch, base_breakpoint) != 0)

    {

      status = 0;

    }

  base_breakpoint = NULL;

  /* Note that it is possible that we have stopped at a location that

     is different from the location where we inserted our breakpoint.

     On mips-irix, we can actually land in __dbx_init(), so we should

     not check the PC against our breakpoint address here.  See procfs.c

     for more details.  */

  return (status);

}

/*

   LOCAL FUNCTION

   enable_break -- arrange for dynamic linker to hit breakpoint

   SYNOPSIS

   int enable_break (void)

   DESCRIPTION

   This functions inserts a breakpoint at the entry point of the

   main executable, where all shared libraries are mapped in.

 */

static int

enable_break (void)

{

  if (symfile_objfile != NULL && has_stack_frames ())

    {

      struct frame_info *frame = get_current_frame ();

      struct address_space *aspace = get_frame_address_space (frame);

      CORE_ADDR entry_point;

      if (!entry_point_address_query (&entry_point))

        return 0;

      base_breakpoint = deprecated_insert_raw_breakpoint (target_gdbarch,

                                                          aspace, entry_point);

      if (base_breakpoint != NULL)

        return 1;

    }

  return 0;

}

/*

   LOCAL FUNCTION

   irix_solib_create_inferior_hook -- shared library startup support

   SYNOPSIS

   void solib_create_inferior_hook (int from_tty)

   DESCRIPTION

   When gdb starts up the inferior, it nurses it along (through the

   shell) until it is ready to execute it's first instruction.  At this

   point, this function gets called via expansion of the macro

   SOLIB_CREATE_INFERIOR_HOOK.

   For SunOS executables, this first instruction is typically the

   one at "_start", or a similar text label, regardless of whether

   the executable is statically or dynamically linked.  The runtime

   startup code takes care of dynamically linking in any shared

   libraries, once gdb allows the inferior to continue.

   For SVR4 executables, this first instruction is either the first

   instruction in the dynamic linker (for dynamically linked

   executables) or the instruction at "start" for statically linked

   executables.  For dynamically linked executables, the system

   first exec's /lib/libc.so.N, which contains the dynamic linker,

   and starts it running.  The dynamic linker maps in any needed

   shared libraries, maps in the actual user executable, and then

   jumps to "start" in the user executable.

   For both SunOS shared libraries, and SVR4 shared libraries, we

   can arrange to cooperate with the dynamic linker to discover the

   names of shared libraries that are dynamically linked, and the

   base addresses to which they are linked.

   This function is responsible for discovering those names and

   addresses, and saving sufficient information about them to allow

   their symbols to be read at a later time.

   FIXME

   Between enable_break() and disable_break(), this code does not

   properly handle hitting breakpoints which the user might have

   set in the startup code or in the dynamic linker itself.  Proper

   handling will probably have to wait until the implementation is

   changed to use the "breakpoint handler function" method.

   Also, what if child has exit()ed?  Must exit loop somehow.

 */

static void

irix_solib_create_inferior_hook (int from_tty)

{

  struct inferior *inf;

  struct thread_info *tp;

  inf = current_inferior ();

  /* If we are attaching to the inferior, the shared libraries

     have already been mapped, so nothing more to do.  */

  if (inf->attach_flag)

    return;

  /* Likewise when debugging from a core file, the shared libraries

     have already been mapped, so nothing more to do.  */

  if (!target_can_run (&current_target))

    return;

  if (!enable_break ())

    {

      warning (_("shared library handler failed to enable breakpoint"));

      return;

    }

  /* Now run the target.  It will eventually hit the breakpoint, at

     which point all of the libraries will have been mapped in and we

     can go groveling around in the dynamic linker structures to find

     out what we need to know about them. */

  tp = inferior_thread ();

  clear_proceed_status ();

  inf->stop_soon = STOP_QUIETLY;

  tp->stop_signal = TARGET_SIGNAL_0;

  do

    {

      target_resume (pid_to_ptid (-1), 0, tp->stop_signal);

      wait_for_inferior (0);

    }

  while (tp->stop_signal != TARGET_SIGNAL_TRAP);

  /* We are now either at the "mapping complete" breakpoint (or somewhere

     else, a condition we aren't prepared to deal with anyway), so adjust

     the PC as necessary after a breakpoint, disable the breakpoint, and

     add any shared libraries that were mapped in. */

  if (!disable_break ())

    {

      warning (_("shared library handler failed to disable breakpoint"));

    }

  /* solib_add will call reinit_frame_cache.

     But we are stopped in the startup code and we might not have symbols

     for the startup code, so heuristic_proc_start could be called

     and will put out an annoying warning.

     Delaying the resetting of stop_soon until after symbol loading

     suppresses the warning.  */

  solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);

  inf->stop_soon = NO_STOP_QUIETLY;

}

/* LOCAL FUNCTION

   current_sos -- build a list of currently loaded shared objects

   SYNOPSIS

   struct so_list *current_sos ()

   DESCRIPTION

   Build a list of `struct so_list' objects describing the shared

   objects currently loaded in the inferior.  This list does not

   include an entry for the main executable file.

   Note that we only gather information directly available from the

   inferior --- we don't examine any of the shared library files

   themselves.  The declaration of `struct so_list' says which fields

   we provide values for.  */

static struct so_list *

irix_current_sos (void)

{

  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);

  int addr_size = gdbarch_addr_bit (target_gdbarch) / TARGET_CHAR_BIT;

  CORE_ADDR lma;

  char addr_buf[8];

  struct so_list *head = 0;

  struct so_list **link_ptr = &head;

  int is_first = 1;

  struct lm_info lm;

  /* Make sure we've looked up the inferior's dynamic linker's base

     structure.  */

  if (!debug_base)

    {

      debug_base = locate_base ();

      /* If we can't find the dynamic linker's base structure, this

         must not be a dynamically linked executable.  Hmm.  */

      if (!debug_base)

        return 0;

    }

  read_memory (debug_base, addr_buf, addr_size);

  lma = extract_mips_address (addr_buf, addr_size, byte_order);

  while (lma)

    {

      lm = fetch_lm_info (lma);

      if (!is_first)

        {

          int errcode;

          char *name_buf;

          int name_size;

          struct so_list *new

            = (struct so_list *) xmalloc (sizeof (struct so_list));

          struct cleanup *old_chain = make_cleanup (xfree, new);

          memset (new, 0, sizeof (*new));

          new->lm_info = xmalloc (sizeof (struct lm_info));

          make_cleanup (xfree, new->lm_info);

          *new->lm_info = lm;

          /* Extract this shared object's name.  */

          name_size = lm.pathname_len;

          if (name_size == 0)

            name_size = SO_NAME_MAX_PATH_SIZE - 1;

          if (name_size >= SO_NAME_MAX_PATH_SIZE)

            {

              name_size = SO_NAME_MAX_PATH_SIZE - 1;

              warning

                ("current_sos: truncating name of %d characters to only %d characters",

                 lm.pathname_len, name_size);

            }

          target_read_string (lm.pathname_addr, &name_buf,

                              name_size, &errcode);

          if (errcode != 0)

            warning (_("Can't read pathname for load map: %s."),

                       safe_strerror (errcode));

          else

            {

              strncpy (new->so_name, name_buf, name_size);

              new->so_name[name_size] = '\0';

              xfree (name_buf);

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

            }

          new->next = 0;

          *link_ptr = new;

          link_ptr = &new->next;

          discard_cleanups (old_chain);

        }

      is_first = 0;

      lma = lm.next;

    }

  return head;

}

/*

  LOCAL FUNCTION

  irix_open_symbol_file_object

  SYNOPSIS

  void irix_open_symbol_file_object (void *from_tty)

  DESCRIPTION

  If no open symbol file, attempt to locate and open the main symbol

  file.  On IRIX, this is the first link map entry.  If its name is

  here, we can open it.  Useful when attaching to a process without

  first loading its symbol file.

  If FROM_TTYP dereferences to a non-zero integer, allow messages to

  be printed.  This parameter is a pointer rather than an int because

  open_symbol_file_object() is called via catch_errors() and

  catch_errors() requires a pointer argument. */

static int

irix_open_symbol_file_object (void *from_ttyp)

{

  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);

  int addr_size = gdbarch_addr_bit (target_gdbarch) / TARGET_CHAR_BIT;

  CORE_ADDR lma;

  char addr_buf[8];

  struct lm_info lm;

  struct cleanup *cleanups;

  int errcode;

  int from_tty = *(int *) from_ttyp;

  char *filename;

  if (symfile_objfile)

    if (!query (_("Attempt to reload symbols from process? ")))

      return 0;

  if ((debug_base = locate_base ()) == 0)

    return 0;                    /* failed somehow...  */

  /* First link map member should be the executable.  */

  read_memory (debug_base, addr_buf, addr_size);

  lma = extract_mips_address (addr_buf, addr_size, byte_order);

  if (lma == 0)

    return 0;                    /* failed somehow...  */

  lm = fetch_lm_info (lma);

  if (lm.pathname_addr == 0)

    return 0;                    /* No filename.  */

  /* Now fetch the filename from target memory.  */

  target_read_string (lm.pathname_addr, &filename, SO_NAME_MAX_PATH_SIZE - 1,

                      &errcode);

  if (errcode)

    {

      warning (_("failed to read exec filename from attached file: %s"),

               safe_strerror (errcode));

      return 0;

    }

  cleanups = make_cleanup (xfree, filename);

  /* Have a pathname: read the symbol file.  */

  symbol_file_add_main (filename, from_tty);

  do_cleanups (cleanups);

  return 1;

}

/*

   LOCAL FUNCTION

   irix_special_symbol_handling -- additional shared library symbol handling

   SYNOPSIS

   void irix_special_symbol_handling ()

   DESCRIPTION

   Once the symbols from a shared object have been loaded in the usual

   way, we are called to do any system specific symbol handling that

   is needed.

   For SunOS4, this consisted of grunging around in the dynamic

   linkers structures to find symbol definitions for "common" symbols

   and adding them to the minimal symbol table for the runtime common

   objfile.

   However, for IRIX, there's nothing to do.

 */

static void

irix_special_symbol_handling (void)

{

}

/* Using the solist entry SO, relocate the addresses in SEC.  */

static void

irix_relocate_section_addresses (struct so_list *so,

                                 struct target_section *sec)

{

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

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

}

/* Free the lm_info struct.  */

static void

irix_free_so (struct so_list *so)

{

  xfree (so->lm_info);

}

/* Clear backend specific state.  */

static void

irix_clear_solib (void)

{

  debug_base = 0;

}

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

   run time loader.  */

static int

irix_in_dynsym_resolve_code (CORE_ADDR pc)

{

  return 0;

}

struct target_so_ops irix_so_ops;

/* Provide a prototype to silence -Wmissing-prototypes.  */

extern initialize_file_ftype _initialize_irix_solib;

void

_initialize_irix_solib (void)

{

  irix_so_ops.relocate_section_addresses = irix_relocate_section_addresses;

  irix_so_ops.free_so = irix_free_so;

  irix_so_ops.clear_solib = irix_clear_solib;

  irix_so_ops.solib_create_inferior_hook = irix_solib_create_inferior_hook;

  irix_so_ops.special_symbol_handling = irix_special_symbol_handling;

  irix_so_ops.current_sos = irix_current_sos;