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

   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,

   2001

   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 2 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, write to the Free Software

   Foundation, Inc., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

#include "defs.h"

#include <sys/types.h>

#include <signal.h>

#include "gdb_string.h"

#include <sys/param.h>

#include <fcntl.h>

 /* SunOS shared libs need the nlist structure.  */

#include <a.out.h>

#include <link.h>

#include "symtab.h"

#include "bfd.h"

#include "symfile.h"

#include "objfiles.h"

#include "gdbcore.h"

#include "inferior.h"

#include "solist.h"

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

struct lm_info

  {

    /* Pointer to copy of link map from inferior.  The type is char *

       rather than void *, so that we may use byte offsets to find the

       various fields without the need for a cast.  */

    char *lm;

  };

/* Symbols which are used to locate the base of the link map structures. */

static char *debug_base_symbols[] =

{

  "_DYNAMIC",

  "_DYNAMIC__MGC",

  NULL

};

static char *main_name_list[] =

{

  "main_$main",

  NULL

};

/* Macro to extract an address from a solib structure.

   When GDB is configured for some 32-bit targets (e.g. Solaris 2.7

   sparc), BFD is configured to handle 64-bit targets, so CORE_ADDR is

   64 bits.  We have to extract only the significant bits of addresses

   to get the right address when accessing the core file BFD.  */

#define SOLIB_EXTRACT_ADDRESS(MEMBER) \

        extract_address (&(MEMBER), sizeof (MEMBER))

/* local data declarations */

static struct link_dynamic dynamic_copy;

static struct link_dynamic_2 ld_2_copy;

static struct ld_debug debug_copy;

static CORE_ADDR debug_addr;

static CORE_ADDR flag_addr;

#ifndef offsetof

#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)

#endif

#define fieldsize(TYPE, MEMBER) (sizeof (((TYPE *)0)->MEMBER))

/* link map access functions */

static CORE_ADDR

LM_ADDR (struct so_list *so)

{

  int lm_addr_offset = offsetof (struct link_map, lm_addr);

  int lm_addr_size = fieldsize (struct link_map, lm_addr);

  return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lm_addr_offset,

                                             lm_addr_size);

}

static CORE_ADDR

LM_NEXT (struct so_list *so)

{

  int lm_next_offset = offsetof (struct link_map, lm_next);

  int lm_next_size = fieldsize (struct link_map, lm_next);

  return extract_address (so->lm_info->lm + lm_next_offset, lm_next_size);

}

static CORE_ADDR

LM_NAME (struct so_list *so)

{

  int lm_name_offset = offsetof (struct link_map, lm_name);

  int lm_name_size = fieldsize (struct link_map, lm_name);

  return extract_address (so->lm_info->lm + lm_name_offset, lm_name_size);

}

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

/* Local function prototypes */

static int match_main (char *);

/* Allocate the runtime common object file.  */

static void

allocate_rt_common_objfile (void)

{

  struct objfile *objfile;

  struct objfile *last_one;

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

  memset (objfile, 0, sizeof (struct objfile));

  objfile->md = NULL;

  objfile->psymbol_cache = bcache_xmalloc ();

  objfile->macro_cache = bcache_xmalloc ();

  obstack_specify_allocation (&objfile->psymbol_obstack, 0, 0, xmalloc,

                              xfree);

  obstack_specify_allocation (&objfile->symbol_obstack, 0, 0, xmalloc,

                              xfree);

  obstack_specify_allocation (&objfile->type_obstack, 0, 0, xmalloc,

                              xfree);

  objfile->name = mstrsave (objfile->md, "rt_common");

  /* Add this file onto the tail of the linked list of other such files. */

  objfile->next = NULL;

  if (object_files == NULL)

    object_files = objfile;

  else

    {

      for (last_one = object_files;

           last_one->next;

           last_one = last_one->next);

      last_one->next = objfile;

    }

  rt_common_objfile = objfile;

}

/* Read all dynamically loaded common symbol definitions from the inferior

   and put them into the minimal symbol table for the runtime common

   objfile.  */

static void

solib_add_common_symbols (CORE_ADDR rtc_symp)

{

  struct rtc_symb inferior_rtc_symb;

  struct nlist inferior_rtc_nlist;

  int len;

  char *name;

  /* Remove any runtime common symbols from previous runs.  */

  if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count)

    {

      obstack_free (&rt_common_objfile->symbol_obstack, 0);

      obstack_specify_allocation (&rt_common_objfile->symbol_obstack, 0, 0,

                                  xmalloc, xfree);

      rt_common_objfile->minimal_symbol_count = 0;

      rt_common_objfile->msymbols = NULL;

    }

  init_minimal_symbol_collection ();

  make_cleanup_discard_minimal_symbols ();

  while (rtc_symp)

    {

      read_memory (rtc_symp,

                   (char *) &inferior_rtc_symb,

                   sizeof (inferior_rtc_symb));

      read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_sp),

                   (char *) &inferior_rtc_nlist,

                   sizeof (inferior_rtc_nlist));

      if (inferior_rtc_nlist.n_type == N_COMM)

        {

          /* FIXME: The length of the symbol name is not available, but in the

             current implementation the common symbol is allocated immediately

             behind the name of the symbol. */

          len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx;

          name = xmalloc (len);

          read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_nlist.n_un.n_name),

                       name, len);

          /* Allocate the runtime common objfile if necessary. */

          if (rt_common_objfile == NULL)

            allocate_rt_common_objfile ();

          prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value,

                                      mst_bss, rt_common_objfile);

          xfree (name);

        }

      rtc_symp = SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_next);

    }

  /* Install any minimal symbols that have been collected as the current

     minimal symbols for the runtime common objfile.  */

  install_minimal_symbols (rt_common_objfile);

}

/*

   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 debug base symbol.  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 a bit more complicated because the address

   is contained somewhere in the dynamic info section.  We have to go

   to a lot more work to discover the address of the debug base symbol.

   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.

 */

static CORE_ADDR

locate_base (void)

{

  struct minimal_symbol *msymbol;

  CORE_ADDR address = 0;

  char **symbolp;

  /* For SunOS, we want to limit the search for the debug base symbol to the

     executable being debugged, since there is a duplicate named symbol in the

     shared library.  We don't want the shared library versions. */

  for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)

    {

      msymbol = lookup_minimal_symbol (*symbolp, NULL, symfile_objfile);

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

        {

          address = SYMBOL_VALUE_ADDRESS (msymbol);

          return (address);

        }

    }

  return (0);

}

/*

   LOCAL FUNCTION

   first_link_map_member -- locate first member in dynamic linker's map

   SYNOPSIS

   static CORE_ADDR first_link_map_member (void)

   DESCRIPTION

   Find the first element in the inferior's dynamic link map, and

   return its address in the inferior.  This function doesn't copy the

   link map entry itself into our address space; current_sos actually

   does the reading.  */

static CORE_ADDR

first_link_map_member (void)

{

  CORE_ADDR lm = 0;

  read_memory (debug_base, (char *) &dynamic_copy, sizeof (dynamic_copy));

  if (dynamic_copy.ld_version >= 2)

    {

      /* It is a version that we can deal with, so read in the secondary

         structure and find the address of the link map list from it. */

      read_memory (SOLIB_EXTRACT_ADDRESS (dynamic_copy.ld_un.ld_2),

                   (char *) &ld_2_copy, sizeof (struct link_dynamic_2));

      lm = SOLIB_EXTRACT_ADDRESS (ld_2_copy.ld_loaded);

    }

  return (lm);

}

static int

open_symbol_file_object (void *from_ttyp)

{

  return 1;

}

/* 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 *

sunos_current_sos (void)

{

  CORE_ADDR lm;

  struct so_list *head = 0;

  struct so_list **link_ptr = &head;

  int errcode;

  char *buffer;

  /* 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;

    }

  /* Walk the inferior's link map list, and build our list of

     `struct so_list' nodes.  */

  lm = first_link_map_member ();

  while (lm)

    {

      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 = xmalloc (sizeof (struct link_map));

      make_cleanup (xfree, new->lm_info->lm);

      memset (new->lm_info->lm, 0, sizeof (struct link_map));

      read_memory (lm, new->lm_info->lm, sizeof (struct link_map));

      lm = LM_NEXT (new);

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

      target_read_string (LM_NAME (new), &buffer,

                          SO_NAME_MAX_PATH_SIZE - 1, &errcode);

      if (errcode != 0)

        {

          warning ("current_sos: Can't read pathname for load map: %s\n",

                   safe_strerror (errcode));

        }

      else

        {

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

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

          xfree (buffer);

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

        }

      /* If this entry has no name, or its name matches the name

         for the main executable, don't include it in the list.  */

      if (! new->so_name[0]

          || match_main (new->so_name))

        free_so (new);

      else

        {

          new->next = 0;

          *link_ptr = new;

          link_ptr = &new->next;

        }

      discard_cleanups (old_chain);

    }

  return head;

}

/* On some systems, the only way to recognize the link map entry for

   the main executable file is by looking at its name.  Return

   non-zero iff SONAME matches one of the known main executable names.  */

static int

match_main (char *soname)

{

  char **mainp;

  for (mainp = main_name_list; *mainp != NULL; mainp++)

    {

      if (strcmp (soname, *mainp) == 0)

        return (1);

    }

  return (0);

}

static int

sunos_in_dynsym_resolve_code (CORE_ADDR pc)

{

  return 0;

}

/*

   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)

{

  CORE_ADDR breakpoint_addr;    /* Address where end bkpt is set */

  int in_debugger = 0;

  /* Read the debugger structure from the inferior to retrieve the

     address of the breakpoint and the original contents of the

     breakpoint address.  Remove the breakpoint by writing the original

     contents back. */

  read_memory (debug_addr, (char *) &debug_copy, sizeof (debug_copy));

  /* Set `in_debugger' to zero now. */

  write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));

  breakpoint_addr = SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_bp_addr);

  write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst,

                sizeof (debug_copy.ldd_bp_inst));

  /* For the SVR4 version, we always know the breakpoint address.  For the

     SunOS version we don't know it until the above code is executed.

     Grumble if we are stopped anywhere besides the breakpoint address. */

  if (stop_pc != breakpoint_addr)

    {

      warning ("stopped at unknown breakpoint while handling shared libraries");

    }

  return 1;

}

/*

   LOCAL FUNCTION

   enable_break -- arrange for dynamic linker to hit breakpoint

   SYNOPSIS

   int enable_break (void)

   DESCRIPTION

   Both the SunOS and the SVR4 dynamic linkers have, as part of their

   debugger interface, support for arranging for the inferior to hit

   a breakpoint after mapping in the shared libraries.  This function

   enables that breakpoint.

   For SunOS, there is a special flag location (in_debugger) which we

   set to 1.  When the dynamic linker sees this flag set, it will set

   a breakpoint at a location known only to itself, after saving the

   original contents of that place and the breakpoint address itself,

   in it's own internal structures.  When we resume the inferior, it

   will eventually take a SIGTRAP when it runs into the breakpoint.

   We handle this (in a different place) by restoring the contents of

   the breakpointed location (which is only known after it stops),

   chasing around to locate the shared libraries that have been

   loaded, then resuming.

   For SVR4, the debugger interface structure contains a member (r_brk)

   which is statically initialized at the time the shared library is

   built, to the offset of a function (_r_debug_state) which is guaran-

   teed to be called once before mapping in a library, and again when

   the mapping is complete.  At the time we are examining this member,

   it contains only the unrelocated offset of the function, so we have

   to do our own relocation.  Later, when the dynamic linker actually

   runs, it relocates r_brk to be the actual address of _r_debug_state().

   The debugger interface structure also contains an enumeration which

   is set to either RT_ADD or RT_DELETE prior to changing the mapping,

   depending upon whether or not the library is being mapped or unmapped,

   and then set to RT_CONSISTENT after the library is mapped/unmapped.

 */

static int

enable_break (void)

{

  int success = 0;

  int j;

  int in_debugger;

  /* Get link_dynamic structure */

  j = target_read_memory (debug_base, (char *) &dynamic_copy,

                          sizeof (dynamic_copy));

  if (j)

    {

      /* unreadable */

      return (0);

    }

  /* Calc address of debugger interface structure */

  debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd);

  /* Calc address of `in_debugger' member of debugger interface structure */

  flag_addr = debug_addr + (CORE_ADDR) ((char *) &debug_copy.ldd_in_debugger -

                                        (char *) &debug_copy);

  /* Write a value of 1 to this member.  */

  in_debugger = 1;

  write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));

  success = 1;

  return (success);

}

/*

   LOCAL FUNCTION

   special_symbol_handling -- additional shared library symbol handling

   SYNOPSIS

   void 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 consists 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.

 */

static void

sunos_special_symbol_handling (void)

{

  int j;

  if (debug_addr == 0)

    {

      /* Get link_dynamic structure */

      j = target_read_memory (debug_base, (char *) &dynamic_copy,

                              sizeof (dynamic_copy));

      if (j)

        {

          /* unreadable */

          return;

        }

      /* Calc address of debugger interface structure */

      /* FIXME, this needs work for cross-debugging of core files

         (byteorder, size, alignment, etc).  */

      debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd);

    }

  /* Read the debugger structure from the inferior, just to make sure

     we have a current copy. */

  j = target_read_memory (debug_addr, (char *) &debug_copy,

                          sizeof (debug_copy));

  if (j)

    return;                     /* unreadable */

  /* Get common symbol definitions for the loaded object. */

  if (debug_copy.ldd_cp)

    {

      solib_add_common_symbols (SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_cp));

    }

}

/* Relocate the main executable.  This function should be called upon

   stopping the inferior process at the entry point to the program.

   The entry point from BFD is compared to the PC and if they are

   different, the main executable is relocated by the proper amount.

   As written it will only attempt to relocate executables which

   lack interpreter sections.  It seems likely that only dynamic

   linker executables will get relocated, though it should work

   properly for a position-independent static executable as well.  */

static void

sunos_relocate_main_executable (void)

{

  asection *interp_sect;

  CORE_ADDR pc = read_pc ();

  /* Decide if the objfile needs to be relocated.  As indicated above,

     we will only be here when execution is stopped at the beginning

     of the program.  Relocation is necessary if the address at which

     we are presently stopped differs from the start address stored in

     the executable AND there's no interpreter section.  The condition

     regarding the interpreter section is very important because if

     there *is* an interpreter section, execution will begin there

     instead.  When there is an interpreter section, the start address

     is (presumably) used by the interpreter at some point to start

     execution of the program.

     If there is an interpreter, it is normal for it to be set to an

     arbitrary address at the outset.  The job of finding it is

     handled in enable_break().

     So, to summarize, relocations are necessary when there is no

     interpreter section and the start address obtained from the

     executable is different from the address at which GDB is

     currently stopped.

     [ The astute reader will note that we also test to make sure that

       the executable in question has the DYNAMIC flag set.  It is my

       opinion that this test is unnecessary (undesirable even).  It

       was added to avoid inadvertent relocation of an executable

       whose e_type member in the ELF header is not ET_DYN.  There may

       be a time in the future when it is desirable to do relocations

       on other types of files as well in which case this condition

       should either be removed or modified to accomodate the new file

       type.  (E.g, an ET_EXEC executable which has been built to be

       position-independent could safely be relocated by the OS if

       desired.  It is true that this violates the ABI, but the ABI

       has been known to be bent from time to time.)  - Kevin, Nov 2000. ]

     */

  interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");

  if (interp_sect == NULL

      && (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0

      && bfd_get_start_address (exec_bfd) != pc)

    {

      struct cleanup *old_chain;

      struct section_offsets *new_offsets;

      int i, changed;

      CORE_ADDR displacement;

      /* It is necessary to relocate the objfile.  The amount to

         relocate by is simply the address at which we are stopped

         minus the starting address from the executable.

         We relocate all of the sections by the same amount.  This

         behavior is mandated by recent editions of the System V ABI.

         According to the System V Application Binary Interface,

         Edition 4.1, page 5-5:

           ...  Though the system chooses virtual addresses for

           individual processes, it maintains the segments' relative

           positions.  Because position-independent code uses relative

           addressesing between segments, the difference between

           virtual addresses in memory must match the difference

           between virtual addresses in the file.  The difference

           between the virtual address of any segment in memory and

           the corresponding virtual address in the file is thus a

           single constant value for any one executable or shared

           object in a given process.  This difference is the base

           address.  One use of the base address is to relocate the

           memory image of the program during dynamic linking.

         The same language also appears in Edition 4.0 of the System V

         ABI and is left unspecified in some of the earlier editions.  */

      displacement = pc - bfd_get_start_address (exec_bfd);

      changed = 0;

      new_offsets = xcalloc (symfile_objfile->num_sections,

                             sizeof (struct section_offsets));

      old_chain = make_cleanup (xfree, new_offsets);

      for (i = 0; i < symfile_objfile->num_sections; i++)

        {

          if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))

            changed = 1;

          new_offsets->offsets[i] = displacement;

        }

      if (changed)

        objfile_relocate (symfile_objfile, new_offsets);

      do_cleanups (old_chain);

    }

}

/*

   GLOBAL FUNCTION

   sunos_solib_create_inferior_hook -- shared library startup support

   SYNOPSIS

   void sunos_solib_create_inferior_hook()

   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