Split SVR4/SunOS solib support.

1 files changed, 896 insertions, 0 deletions

diff --git a/gdb/solib-sunos.c b/gdb/solib-sunos.c
new file mode 100644
index 0000000..b5d9586
--- /dev/null
+++ b/gdb/solib-sunos.c
@@ -0,0 +1,896 @@
+/* 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;
+  obstack_specify_allocation (&objfile->psymbol_cache.cache, 0, 0,
+			      xmalloc, xfree);
+  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 (sizeof (struct section_offsets),
+			     symfile_objfile->num_sections);
+      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
+   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
+sunos_solib_create_inferior_hook (void)
+{
+  /* Relocate the main executable if necessary.  */
+  sunos_relocate_main_executable ();
+
+  if ((debug_base = locate_base ()) == 0)
+    {
+      /* Can't find the symbol or the executable is statically linked. */
+      return;
+    }
+
+  if (!enable_break ())
+    {
+      warning ("shared library handler failed to enable breakpoint");
+      return;
+    }
+
+  /* SCO and SunOS need the loop below, other systems should be using the
+     special shared library breakpoints and the shared library breakpoint
+     service routine.
+
+     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. */
+
+  clear_proceed_status ();
+  stop_soon_quietly = 1;
+  stop_signal = TARGET_SIGNAL_0;
+  do
+    {
+      target_resume (pid_to_ptid (-1), 0, stop_signal);
+      wait_for_inferior ();
+    }
+  while (stop_signal != TARGET_SIGNAL_TRAP);
+  stop_soon_quietly = 0;
+
+  /* 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 (DECR_PC_AFTER_BREAK)
+    {
+      stop_pc -= DECR_PC_AFTER_BREAK;
+      write_register (PC_REGNUM, stop_pc);
+    }
+
+  if (!disable_break ())
+    {
+      warning ("shared library handler failed to disable breakpoint");
+    }
+
+  if (auto_solib_add)
+    solib_add ((char *) 0, 0, (struct target_ops *) 0);
+}
+
+static void
+sunos_clear_solib (void)
+{
+  debug_base = 0;
+}
+
+static void
+sunos_free_so (struct so_list *so)
+{
+  xfree (so->lm_info->lm);
+  xfree (so->lm_info);
+}
+
+static void
+sunos_relocate_section_addresses (struct so_list *so,
+                                 struct section_table *sec)
+{
+  sec->addr += LM_ADDR (so);
+  sec->endaddr += LM_ADDR (so);
+}
+
+static struct target_so_ops sunos_so_ops;
+
+void
+_initialize_sunos_solib (void)
+{
+  sunos_so_ops.relocate_section_addresses = sunos_relocate_section_addresses;
+  sunos_so_ops.free_so = sunos_free_so;
+  sunos_so_ops.clear_solib = sunos_clear_solib;
+  sunos_so_ops.solib_create_inferior_hook = sunos_solib_create_inferior_hook;
+  sunos_so_ops.special_symbol_handling = sunos_special_symbol_handling;
+  sunos_so_ops.current_sos = sunos_current_sos;
+  sunos_so_ops.open_symbol_file_object = open_symbol_file_object;
+  sunos_so_ops.in_dynsym_resolve_code = sunos_in_dynsym_resolve_code;
+
+  /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops. */
+  current_target_so_ops = &sunos_so_ops;
+}