* solib-aix5.c: New file.

1 files changed, 860 insertions, 0 deletions

diff --git a/gdb/solib-aix5.c b/gdb/solib-aix5.c
new file mode 100644
index 0000000..48e6b2a
--- /dev/null
+++ b/gdb/solib-aix5.c
@@ -0,0 +1,860 @@
+/* Handle AIX5 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>
+#include <sys/procfs.h>
+
+#include "elf/external.h"
+
+#include "symtab.h"
+#include "bfd.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "gdbcore.h"
+#include "command.h"
+#include "target.h"
+#include "frame.h"
+#include "gdb_regex.h"
+#include "inferior.h"
+#include "environ.h"
+#include "language.h"
+#include "gdbcmd.h"
+
+#include "solist.h"
+#include "solib-svr4.h"
+
+/* Link map info to include in an allocated so_list entry */
+
+enum maptype {
+  MT_READONLY = 0,
+  MT_READWRITE = 1,
+  MT_LAST = 2
+};
+
+struct lm_info
+  {
+    struct
+      {
+	CORE_ADDR addr;		/* base address */
+	CORE_ADDR size;		/* size of mapped object */
+	CORE_ADDR offset;	/* offset into mapped object */
+	long flags;		/* MA_ protection and attribute flags */
+	CORE_ADDR gp;		/* global pointer value */
+      } mapping[MT_LAST];
+      char *mapname;		/* name in /proc/pid/object */
+      char *pathname;		/* full pathname to object */
+      char *membername;		/* member name in archive file */
+  };
+
+/* On SVR4 systems, a list of symbols in the dynamic linker where
+   GDB can try to place a breakpoint to monitor shared library
+   events.
+
+   If none of these symbols are found, or other errors occur, then
+   SVR4 systems will fall back to using a symbol as the "startup
+   mapping complete" breakpoint address.  */
+
+static char *solib_break_names[] =
+{
+  "r_debug_state",
+  "_r_debug_state",
+  "_dl_debug_state",
+  "rtld_db_dlactivity",
+  NULL
+};
+
+static char *bkpt_names[] =
+{
+#ifdef SOLIB_BKPT_NAME
+  SOLIB_BKPT_NAME,		/* Prefer configured name if it exists. */
+#endif
+  "_start",
+  "main",
+  NULL
+};
+
+static void aix5_relocate_main_executable (void);
+
+/*
+
+   LOCAL FUNCTION
+
+   bfd_lookup_symbol -- lookup the value for a specific symbol
+
+   SYNOPSIS
+
+   CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
+
+   DESCRIPTION
+
+   An expensive way to lookup the value of a single symbol for
+   bfd's that are only temporary anyway.  This is used by the
+   shared library support to find the address of the debugger
+   interface structures in the shared library.
+
+   Note that 0 is specifically allowed as an error return (no
+   such symbol).
+ */
+
+static CORE_ADDR
+bfd_lookup_symbol (bfd *abfd, char *symname)
+{
+  unsigned int storage_needed;
+  asymbol *sym;
+  asymbol **symbol_table;
+  unsigned int number_of_symbols;
+  unsigned int i;
+  struct cleanup *back_to;
+  CORE_ADDR symaddr = 0;
+
+  storage_needed = bfd_get_symtab_upper_bound (abfd);
+
+  if (storage_needed > 0)
+    {
+      symbol_table = (asymbol **) xmalloc (storage_needed);
+      back_to = make_cleanup (free, (PTR) symbol_table);
+      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
+
+      for (i = 0; i < number_of_symbols; i++)
+	{
+	  sym = *symbol_table++;
+	  if (STREQ (sym->name, symname))
+	    {
+	      /* Bfd symbols are section relative. */
+	      symaddr = sym->value + sym->section->vma;
+	      break;
+	    }
+	}
+      do_cleanups (back_to);
+    }
+
+  if (symaddr)
+    return symaddr;
+
+  /* On FreeBSD, the dynamic linker is stripped by default.  So we'll
+     have to check the dynamic string table too.  */
+
+  storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
+/* FIXME: This problem should be addressed in BFD.  */
+#define REASONABLE_LIMIT 0x400000
+  if (storage_needed > REASONABLE_LIMIT)
+    storage_needed = REASONABLE_LIMIT;
+
+  if (storage_needed > 0)
+    {
+      symbol_table = (asymbol **) xmalloc (storage_needed);
+      back_to = make_cleanup (free, (PTR) symbol_table);
+      number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
+
+      for (i = 0; i < number_of_symbols; i++)
+	{
+	  sym = *symbol_table++;
+	  if (STREQ (sym->name, symname))
+	    {
+	      /* Bfd symbols are section relative. */
+	      symaddr = sym->value + sym->section->vma;
+	      break;
+	    }
+	}
+      do_cleanups (back_to);
+    }
+
+  return symaddr;
+}
+
+
+/* Read /proc/PID/map and build a list of shared objects such that
+   the pr_mflags value AND'd with MATCH_MASK is equal to MATCH_VAL.
+   This gives us a convenient way to find all of the mappings that
+   don't belong to the main executable or vice versa.  Here are
+   some of the possibilities:
+
+    - Fetch all mappings:
+        MATCH_MASK: 0
+        MATCH_VAL: 0
+    - Fetch all mappings except for main executable:
+        MATCH_MASK: MA_MAINEXEC
+	MATCH_VAL: 0
+    - Fetch only main executable:
+        MATCH_MASK: MA_MAINEXEC
+	MATCH_VAL: MA_MAINEXEC
+	
+   A cleanup chain for the list allocations done by this function should
+   be established prior to calling build_so_list_from_mapfile().  */
+
+static struct so_list *
+build_so_list_from_mapfile (int pid, long match_mask, long match_val)
+{
+  char *mapbuf = NULL;
+  struct prmap *prmap;
+  int mapbuf_size;
+  struct so_list *sos = NULL;
+
+  {
+    int mapbuf_allocation_size = 8192;
+    char map_pathname[64];
+    int map_fd;
+
+    /* Open the map file */
+
+    sprintf (map_pathname, "/proc/%d/map", pid);
+    map_fd = open (map_pathname, O_RDONLY);
+    if (map_fd < 0)
+      return 0;
+
+    /* Read the entire map file in */
+    do
+      {
+	if (mapbuf)
+	  {
+	    free (mapbuf);
+	    mapbuf_allocation_size *= 2;
+	    lseek (map_fd, 0, SEEK_SET);
+	  }
+	mapbuf = xmalloc (mapbuf_allocation_size);
+	mapbuf_size = read (map_fd, mapbuf, mapbuf_allocation_size);
+	if (mapbuf_size < 0)
+	  {
+	    free (mapbuf);
+	    /* FIXME: This warrants an error or a warning of some sort */
+	    return 0;
+	  }
+      } while (mapbuf_size == mapbuf_allocation_size);
+
+    close (map_fd);
+  }
+
+  for (prmap = (struct prmap *) mapbuf;
+       (char *) prmap < mapbuf + mapbuf_size;
+       prmap++)
+    {
+      char *mapname, *pathname, *membername;
+      struct so_list *sop;
+      enum maptype maptype;
+
+      if (prmap->pr_size == 0)
+	break;
+
+      /* Skip to the next entry if there's no path associated with the
+         map, unless we're looking for the kernel text region, in which
+	 case it's okay if there's no path.  */
+      if ((prmap->pr_pathoff == 0 || prmap->pr_pathoff >= mapbuf_size)
+	  && ((match_mask & MA_KERNTEXT) == 0))
+	continue;
+
+      /* Skip to the next entry if our match conditions don't hold.  */
+      if ((prmap->pr_mflags & match_mask) != match_val)
+	continue;
+
+      mapname = prmap->pr_mapname;
+      if (prmap->pr_pathoff == 0)
+        {
+	  pathname = "";
+	  membername = "";
+	}
+      else
+        {
+	  pathname = mapbuf + prmap->pr_pathoff;
+	  membername = pathname + strlen (pathname) + 1;
+        }
+
+      for (sop = sos; sop != NULL; sop = sop->next)
+	if (strcmp (pathname, sop->lm_info->pathname) == 0
+	    && strcmp (membername, sop->lm_info->membername) == 0)
+	  break;
+
+      if (sop == NULL)
+	{
+	  sop = xcalloc (sizeof (struct so_list), 1);
+	  make_cleanup (free, sop);
+	  sop->lm_info = xcalloc (sizeof (struct lm_info), 1);
+	  make_cleanup (free, sop->lm_info);
+	  sop->lm_info->mapname = xstrdup (mapname);
+	  make_cleanup (free, sop->lm_info->mapname);
+	  /* FIXME: Eliminate the pathname field once length restriction
+	     is lifted on so_name and so_original_name.  */
+	  sop->lm_info->pathname = xstrdup (pathname);
+	  make_cleanup (free, sop->lm_info->pathname);
+	  sop->lm_info->membername = xstrdup (membername);
+	  make_cleanup (free, sop->lm_info->membername);
+
+	  strncpy (sop->so_name, pathname, SO_NAME_MAX_PATH_SIZE - 1);
+	  sop->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
+	  strcpy (sop->so_original_name, sop->so_name);
+
+	  sop->next = sos;
+	  sos = sop;
+	}
+
+      maptype = (prmap->pr_mflags & MA_WRITE) ? MT_READWRITE : MT_READONLY;
+      sop->lm_info->mapping[maptype].addr = (CORE_ADDR) prmap->pr_vaddr;
+      sop->lm_info->mapping[maptype].size = prmap->pr_size;
+      sop->lm_info->mapping[maptype].offset = prmap->pr_off;
+      sop->lm_info->mapping[maptype].flags = prmap->pr_mflags;
+      sop->lm_info->mapping[maptype].gp = (CORE_ADDR) prmap->pr_gp;
+    }
+
+  free (mapbuf);
+  return sos;
+}
+
+/*
+
+  LOCAL FUNCTION
+
+  open_symbol_file_object
+
+  SYNOPSIS
+
+  void open_symbol_file_object (void *from_tty)
+
+  DESCRIPTION
+
+  If no open symbol file, attempt to locate and open the main 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
+open_symbol_file_object (void *from_ttyp)
+{
+  CORE_ADDR lm, l_name;
+  char *filename;
+  int errcode;
+  int from_tty = *(int *)from_ttyp;
+  struct cleanup *old_chain = make_cleanup (null_cleanup, 0);
+  struct so_list *sos;
+
+  sos = build_so_list_from_mapfile (PIDGET (inferior_pid),
+                                    MA_MAINEXEC, MA_MAINEXEC);
+
+
+  if (sos == NULL)
+    {
+      warning ("Could not find name of main executable in map file");
+      return 0;
+    }
+
+  symbol_file_command (sos->lm_info->pathname, from_tty);
+
+  do_cleanups (old_chain);
+
+  aix5_relocate_main_executable ();
+
+  return 1;
+}
+
+/* LOCAL FUNCTION
+
+   aix5_current_sos -- build a list of currently loaded shared objects
+
+   SYNOPSIS
+
+   struct so_list *aix5_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 *
+aix5_current_sos (void)
+{
+  struct cleanup *old_chain = make_cleanup (null_cleanup, 0);
+  struct so_list *sos;
+
+  /* Fetch the list of mappings, excluding the main executable. */
+  sos = build_so_list_from_mapfile (PIDGET (inferior_pid), MA_MAINEXEC, 0);
+
+  /* Reverse the list; it looks nicer when we print it if the mappings
+     are in the same order as in the map file.  */
+  if (sos)
+    {
+      struct so_list *next = sos->next;
+
+      sos->next = 0;
+      while (next)
+	{
+	  struct so_list *prev = sos;
+
+	  sos = next;
+	  next = next->next;
+	  sos->next = prev;
+	}
+    }
+  discard_cleanups (old_chain);
+  return sos;
+}
+
+
+/* Return 1 if PC lies in the dynamic symbol resolution code of the
+   SVR4 run time loader.  */
+
+static CORE_ADDR interp_text_sect_low;
+static CORE_ADDR interp_text_sect_high;
+static CORE_ADDR interp_plt_sect_low;
+static CORE_ADDR interp_plt_sect_high;
+
+/* FIXME: Does this belong here?  (If it does, it ought to be renamed.) */
+int
+in_svr4_dynsym_resolve_code (CORE_ADDR pc)
+{
+  return ((pc >= interp_text_sect_low && pc < interp_text_sect_high)
+	  || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high)
+	  || in_plt_section (pc, NULL));
+}
+
+/*
+
+   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;
+
+  struct minimal_symbol *msymbol;
+  char **bkpt_namep;
+  asection *interp_sect;
+
+  /* First, remove all the solib event breakpoints.  Their addresses
+     may have changed since the last time we ran the program.  */
+  remove_solib_event_breakpoints ();
+
+  interp_text_sect_low = interp_text_sect_high = 0;
+  interp_plt_sect_low = interp_plt_sect_high = 0;
+
+  /* Find the .interp section; if not found, warn the user and drop
+     into the old breakpoint at symbol code.  */
+  interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
+  if (interp_sect)
+    {
+      unsigned int interp_sect_size;
+      char *buf;
+      CORE_ADDR load_addr;
+      bfd *tmp_bfd;
+      CORE_ADDR sym_addr = 0;
+
+      /* Read the contents of the .interp section into a local buffer;
+         the contents specify the dynamic linker this program uses.  */
+      interp_sect_size = bfd_section_size (exec_bfd, interp_sect);
+      buf = alloca (interp_sect_size);
+      bfd_get_section_contents (exec_bfd, interp_sect,
+				buf, 0, interp_sect_size);
+
+      /* Now we need to figure out where the dynamic linker was
+         loaded so that we can load its symbols and place a breakpoint
+         in the dynamic linker itself.
+
+         This address is stored on the stack.  However, I've been unable
+         to find any magic formula to find it for Solaris (appears to
+         be trivial on GNU/Linux).  Therefore, we have to try an alternate
+         mechanism to find the dynamic linker's base address.  */
+      tmp_bfd = bfd_openr (buf, gnutarget);
+      if (tmp_bfd == NULL)
+	goto bkpt_at_symbol;
+
+      /* Make sure the dynamic linker's really a useful object.  */
+      if (!bfd_check_format (tmp_bfd, bfd_object))
+	{
+	  warning ("Unable to grok dynamic linker %s as an object file", buf);
+	  bfd_close (tmp_bfd);
+	  goto bkpt_at_symbol;
+	}
+
+      /* We find the dynamic linker's base address by examining the
+         current pc (which point at the entry point for the dynamic
+         linker) and subtracting the offset of the entry point.  */
+      load_addr = read_pc () - tmp_bfd->start_address;
+
+      /* Record the relocated start and end address of the dynamic linker
+         text and plt section for in_aix5_dynsym_resolve_code.  */
+      interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
+      if (interp_sect)
+	{
+	  interp_text_sect_low =
+	    bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
+	  interp_text_sect_high =
+	    interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+	}
+      interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
+      if (interp_sect)
+	{
+	  interp_plt_sect_low =
+	    bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
+	  interp_plt_sect_high =
+	    interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
+	}
+
+      /* Now try to set a breakpoint in the dynamic linker.  */
+      for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
+	{
+	  sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep);
+	  if (sym_addr != 0)
+	    break;
+	}
+
+      /* We're done with the temporary bfd.  */
+      bfd_close (tmp_bfd);
+
+      if (sym_addr != 0)
+	{
+	  create_solib_event_breakpoint (load_addr + sym_addr);
+	  return 1;
+	}
+
+      /* For whatever reason we couldn't set a breakpoint in the dynamic
+         linker.  Warn and drop into the old code.  */
+    bkpt_at_symbol:
+      warning ("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code.");
+    }
+
+  /* Scan through the list of symbols, trying to look up the symbol and
+     set a breakpoint there.  Terminate loop when we/if we succeed. */
+
+  for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
+    {
+      msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
+      if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
+	{
+	  create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
+	  return 1;
+	}
+    }
+
+  /* Nothing good happened.  */
+  success = 0;
+
+  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.
+
+ */
+
+static void
+aix5_special_symbol_handling (void)
+{
+  /* Nothing needed (yet) for AIX5. */
+}
+
+#define SECTMAPMASK (~ (CORE_ADDR) 0x03ffffff)
+
+static void
+aix5_relocate_main_executable (void)
+{
+  struct so_list *so;
+  struct section_offsets *new_offsets;
+  int i;
+  int changed = 0;
+  struct cleanup *old_chain = make_cleanup (null_cleanup, 0);
+
+  /* Fetch the mappings for the main executable from the map file.  */
+  so = build_so_list_from_mapfile (PIDGET (inferior_pid),
+                                   MA_MAINEXEC, MA_MAINEXEC);
+
+  /* Make sure we actually have some mappings to work with.  */
+  if (so == NULL)
+    {
+      warning ("Could not find main executable in map file");
+      do_cleanups (old_chain);
+      return;
+    }
+
+  /* Allocate the data structure which'll contain the new offsets to
+     relocate by.  Initialize it so it contains the current offsets.  */
+  new_offsets = xcalloc (sizeof (struct section_offsets),
+                         symfile_objfile->num_sections);
+  make_cleanup (free, new_offsets);
+  for (i = 0; i < symfile_objfile->num_sections; i++)
+    ANOFFSET (new_offsets, i) = ANOFFSET (symfile_objfile->section_offsets, i);
+
+  /* Iterate over the mappings in the main executable and compute
+     the new offset value as appropriate.  */
+  for (i = 0; i < MT_LAST; i++)
+    {
+      CORE_ADDR increment = 0;
+      struct obj_section *sect;
+      bfd *obfd = symfile_objfile->obfd;
+
+      ALL_OBJFILE_OSECTIONS (symfile_objfile, sect)
+	{
+	  int flags = bfd_get_section_flags (obfd, sect->the_bfd_section);
+	  if (flags & SEC_ALLOC)
+	    {
+	      if (((so->lm_info->mapping[i].flags & MA_WRITE) == 0)
+		    == ((flags & SEC_READONLY) != 0))
+		{
+		  int idx = sect->the_bfd_section->index;
+
+		  if (increment == 0)
+		    increment = so->lm_info->mapping[i].addr
+		      - (bfd_section_vma (obfd, sect->the_bfd_section) 
+		         & SECTMAPMASK);
+
+		  if (increment != ANOFFSET (new_offsets, idx))
+		    {
+		      ANOFFSET (new_offsets, idx) = increment;
+		      changed = 1;
+		    }
+		}
+	    }
+	}
+    }
+
+  /* If any of the offsets have changed, then relocate the objfile.  */
+  if (changed)
+    objfile_relocate (symfile_objfile, new_offsets);
+
+  /* Free up all the space we've allocated.  */
+  do_cleanups (old_chain);
+}
+
+/*
+
+   GLOBAL FUNCTION
+
+   aix5_solib_create_inferior_hook -- shared library startup support
+
+   SYNOPSIS
+
+   void aix5_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 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.
+
+ */
+
+static void
+aix5_solib_create_inferior_hook (void)
+{
+  aix5_relocate_main_executable ();
+
+  if (!enable_break ())
+    {
+      warning ("shared library handler failed to enable breakpoint");
+      return;
+    }
+}
+
+static void
+aix5_clear_solib (void)
+{
+}
+
+static void
+aix5_free_so (struct so_list *so)
+{
+  free (so->lm_info->mapname);
+  free (so->lm_info->pathname);
+  free (so->lm_info->membername);
+  free (so->lm_info);
+}
+
+static void
+aix5_relocate_section_addresses (struct so_list *so,
+                                 struct section_table *sec)
+{
+  int flags = bfd_get_section_flags (sec->bfd, sec->the_bfd_section);
+
+  if (flags & SEC_ALLOC)
+    {
+      int idx = (flags & SEC_READONLY) ? MT_READONLY : MT_READWRITE;
+      CORE_ADDR addr = so->lm_info->mapping[idx].addr;
+
+      sec->addr += addr;
+      sec->endaddr += addr;
+    }
+}
+
+/* Find the global pointer for the given function address ADDR.  */
+
+static CORE_ADDR
+aix5_find_global_pointer (CORE_ADDR addr)
+{
+  struct so_list *sos, *so;
+  CORE_ADDR global_pointer = 0;
+  struct cleanup *old_chain = make_cleanup (null_cleanup, 0);
+
+  sos = build_so_list_from_mapfile (PIDGET (inferior_pid), 0, 0);
+
+  for (so = sos; so != NULL; so = so->next)
+    {
+      if (so->lm_info->mapping[MT_READONLY].addr <= addr
+          && addr <= so->lm_info->mapping[MT_READONLY].addr
+	               + so->lm_info->mapping[MT_READONLY].size)
+	{
+	  global_pointer = so->lm_info->mapping[MT_READWRITE].gp;
+	  break;
+	}
+    }
+
+  do_cleanups (old_chain);
+
+  return global_pointer;
+}
+
+/* Find the execute-only kernel region known as the gate page.  This
+   page is where the signal trampoline lives.  It may be found by
+   querying the map file and looking for the MA_KERNTEXT flag.  */
+static void
+aix5_find_gate_addresses (CORE_ADDR *start, CORE_ADDR *end)
+{
+  struct so_list *so;
+  struct cleanup *old_chain = make_cleanup (null_cleanup, 0);
+
+  /* Fetch the mappings for the main executable from the map file.  */
+  so = build_so_list_from_mapfile (PIDGET (inferior_pid),
+                                   MA_KERNTEXT, MA_KERNTEXT);
+
+  /* Make sure we actually have some mappings to work with.  */
+  if (so == NULL)
+    {
+      warning ("Could not find gate page in map file");
+      *start = 0;
+      *end = 0;
+      do_cleanups (old_chain);
+      return;
+    }
+
+  /* There should only be on kernel mapping for the gate page and
+     it'll be in the read-only (even though it's execute-only)
+     mapping in the lm_info struct.  */
+
+  *start = so->lm_info->mapping[MT_READONLY].addr;
+  *end = *start + so->lm_info->mapping[MT_READONLY].size;
+
+  /* Free up all the space we've allocated.  */
+  do_cleanups (old_chain);
+}
+
+/* From ia64-tdep.c.  FIXME:  If we end up using this for rs6000 too,
+   we'll need to make the names match.  */
+extern CORE_ADDR (*native_find_global_pointer) (CORE_ADDR);
+
+/* From ia64-aix-tdep.c.  Hook for finding the starting and
+   ending gate page addresses.  The only reason that this hook
+   is in this file is because this is where the map file reading
+   code is located.  */
+extern void (*aix5_find_gate_addresses_hook) (CORE_ADDR *, CORE_ADDR *);
+
+static struct target_so_ops aix5_so_ops;
+
+void
+_initialize_aix5_solib (void)
+{
+  aix5_so_ops.relocate_section_addresses = aix5_relocate_section_addresses;
+  aix5_so_ops.free_so = aix5_free_so;
+  aix5_so_ops.clear_solib = aix5_clear_solib;
+  aix5_so_ops.solib_create_inferior_hook = aix5_solib_create_inferior_hook;
+  aix5_so_ops.special_symbol_handling = aix5_special_symbol_handling;
+  aix5_so_ops.current_sos = aix5_current_sos;
+  aix5_so_ops.open_symbol_file_object = open_symbol_file_object;
+
+  native_find_global_pointer = aix5_find_global_pointer;
+  aix5_find_gate_addresses_hook = aix5_find_gate_addresses;
+
+  /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops. */
+  current_target_so_ops = &aix5_so_ops;
+}
+