2004-12-07 Randolph Chung <tausq@debian.org>

	* solib-som.c: New file.
	* solib-som.h: New file.
	* solib-pa64.c: New file.
	* solib-pa64.h: New file.

1 files changed, 898 insertions, 0 deletions

diff --git a/gdb/solib-som.c b/gdb/solib-som.c
new file mode 100644
index 0000000..38c1803
--- /dev/null
+++ b/gdb/solib-som.c
@@ -0,0 +1,898 @@
+/* Handle SOM shared libraries for GDB, the GNU Debugger.
+
+   Copyright 2004 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 "som.h"
+#include "symtab.h"
+#include "bfd.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "gdbcore.h"
+#include "target.h"
+#include "inferior.h"
+
+#include "hppa-tdep.h"
+#include "solist.h"
+
+#undef SOLIB_SOM_DBG 
+
+/* These ought to be defined in some public interface, but aren't.  They
+   define the meaning of the various bits in the distinguished __dld_flags
+   variable that is declared in every debuggable a.out on HP-UX, and that
+   is shared between the debugger and the dynamic linker.
+ */
+#define DLD_FLAGS_MAPPRIVATE    0x1
+#define DLD_FLAGS_HOOKVALID     0x2
+#define DLD_FLAGS_LISTVALID     0x4
+#define DLD_FLAGS_BOR_ENABLE    0x8
+
+struct lm_info
+  {
+    /* Version of this structure (it is expected to change again in hpux10).  */
+    unsigned char struct_version;
+
+    /* Binding mode for this library.  */
+    unsigned char bind_mode;
+
+    /* Version of this library.  */
+    short library_version;
+
+    /* Start of text address,
+       link-time text location (length of text area),
+       end of text address.  */
+    CORE_ADDR text_addr;
+    CORE_ADDR text_link_addr;
+    CORE_ADDR text_end;
+
+    /* Start of data, start of bss and end of data.  */
+    CORE_ADDR data_start;
+    CORE_ADDR bss_start;
+    CORE_ADDR data_end;
+
+    /* Value of linkage pointer (%r19).  */
+    CORE_ADDR got_value;
+
+    /* Address in target of offset from thread-local register of
+       start of this thread's data.  I.e., the first thread-local
+       variable in this shared library starts at *(tsd_start_addr)
+       from that area pointed to by cr27 (mpsfu_hi).
+      
+       We do the indirection as soon as we read it, so from then
+       on it's the offset itself.  */
+    CORE_ADDR tsd_start_addr;
+
+    /* Address of the link map entry in the loader.  */
+    CORE_ADDR lm_addr;
+  };
+
+/* These addresses should be filled in by som_solib_create_inferior_hook.
+   They are also used elsewhere in this module.
+ */
+typedef struct
+  {
+    CORE_ADDR address;
+    struct unwind_table_entry *unwind;
+  }
+addr_and_unwind_t;
+
+/* When adding fields, be sure to clear them in _initialize_som_solib. */
+static struct
+  {
+    int is_valid;
+    addr_and_unwind_t hook;
+    addr_and_unwind_t hook_stub;
+    addr_and_unwind_t load;
+    addr_and_unwind_t load_stub;
+    addr_and_unwind_t unload;
+    addr_and_unwind_t unload2;
+    addr_and_unwind_t unload_stub;
+  }
+dld_cache;
+
+static void
+som_relocate_section_addresses (struct so_list *so,
+				struct section_table *sec)
+{
+  flagword aflag = bfd_get_section_flags(so->abfd, sec->the_bfd_section);
+
+  /* solib.c does something similar, but it only recognizes ".text", SOM calls
+     the text section "$CODE$".  */
+  if (strcmp (sec->the_bfd_section->name, "$CODE$") == 0)
+    {
+      so->textsection = sec;
+    }
+
+  if (aflag & SEC_CODE)
+    {
+      sec->addr    += so->lm_info->text_addr - so->lm_info->text_link_addr; 
+      sec->endaddr += so->lm_info->text_addr - so->lm_info->text_link_addr;
+    }
+  else if (aflag & SEC_DATA)
+    {
+      sec->addr    += so->lm_info->data_start; 
+      sec->endaddr += so->lm_info->data_start;
+    }
+  else
+    ;
+}
+
+/* This hook gets called just before the first instruction in the
+   inferior process is executed.
+
+   This is our opportunity to set magic flags in the inferior so
+   that GDB can be notified when a shared library is mapped in and
+   to tell the dynamic linker that a private copy of the library is
+   needed (so GDB can set breakpoints in the library).
+
+   __dld_flags is the location of the magic flags; as of this implementation
+   there are 3 flags of interest:
+
+   bit 0 when set indicates that private copies of the libraries are needed
+   bit 1 when set indicates that the callback hook routine is valid
+   bit 2 when set indicates that the dynamic linker should maintain the
+   __dld_list structure when loading/unloading libraries.
+
+   Note that shared libraries are not mapped in at this time, so we have
+   run the inferior until the libraries are mapped in.  Typically this
+   means running until the "_start" is called.  */
+
+static void
+som_solib_create_inferior_hook (void)
+{
+  struct minimal_symbol *msymbol;
+  unsigned int dld_flags, status, have_endo;
+  asection *shlib_info;
+  char buf[4];
+  struct objfile *objfile;
+  CORE_ADDR anaddr;
+
+  /* First, remove all the solib event breakpoints.  Their addresses
+     may have changed since the last time we ran the program.  */
+  remove_solib_event_breakpoints ();
+
+  if (symfile_objfile == NULL)
+    return;
+
+  /* First see if the objfile was dynamically linked.  */
+  shlib_info = bfd_get_section_by_name (symfile_objfile->obfd, "$SHLIB_INFO$");
+  if (!shlib_info)
+    return;
+
+  /* It's got a $SHLIB_INFO$ section, make sure it's not empty.  */
+  if (bfd_section_size (symfile_objfile->obfd, shlib_info) == 0)
+    return;
+
+  have_endo = 0;
+  /* Slam the pid of the process into __d_pid.
+
+     We used to warn when this failed, but that warning is only useful
+     on very old HP systems (hpux9 and older).  The warnings are an
+     annoyance to users of modern systems and foul up the testsuite as
+     well.  As a result, the warnings have been disabled.  */
+  msymbol = lookup_minimal_symbol ("__d_pid", NULL, symfile_objfile);
+  if (msymbol == NULL)
+    goto keep_going;
+
+  anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
+  store_unsigned_integer (buf, 4, PIDGET (inferior_ptid));
+  status = target_write_memory (anaddr, buf, 4);
+  if (status != 0)
+    {
+      warning ("Unable to write __d_pid");
+      warning ("Suggest linking with /opt/langtools/lib/end.o.");
+      warning ("GDB will be unable to track shl_load/shl_unload calls");
+      goto keep_going;
+    }
+
+  /* Get the value of _DLD_HOOK (an export stub) and put it in __dld_hook;
+     This will force the dynamic linker to call __d_trap when significant
+     events occur.
+
+     Note that the above is the pre-HP-UX 9.0 behaviour.  At 9.0 and above,
+     the dld provides an export stub named "__d_trap" as well as the
+     function named "__d_trap" itself, but doesn't provide "_DLD_HOOK".
+     We'll look first for the old flavor and then the new.
+   */
+  msymbol = lookup_minimal_symbol ("_DLD_HOOK", NULL, symfile_objfile);
+  if (msymbol == NULL)
+    msymbol = lookup_minimal_symbol ("__d_trap", NULL, symfile_objfile);
+  if (msymbol == NULL)
+    {
+      warning ("Unable to find _DLD_HOOK symbol in object file.");
+      warning ("Suggest linking with /opt/langtools/lib/end.o.");
+      warning ("GDB will be unable to track shl_load/shl_unload calls");
+      goto keep_going;
+    }
+  anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
+  dld_cache.hook.address = anaddr;
+
+  /* Grrr, this might not be an export symbol!  We have to find the
+     export stub.  */
+  ALL_OBJFILES (objfile)
+  {
+    struct unwind_table_entry *u;
+    struct minimal_symbol *msymbol2;
+
+    /* What a crock.  */
+    msymbol2 =
+      lookup_minimal_symbol_solib_trampoline (SYMBOL_LINKAGE_NAME (msymbol),
+					      objfile);
+    /* Found a symbol with the right name.  */
+    if (msymbol2)
+      {
+	struct unwind_table_entry *u;
+	/* It must be a shared library trampoline.  */
+	if (SYMBOL_TYPE (msymbol2) != mst_solib_trampoline)
+	  continue;
+
+	/* It must also be an export stub.  */
+	u = find_unwind_entry (SYMBOL_VALUE (msymbol2));
+	if (!u || u->stub_unwind.stub_type != EXPORT)
+	  continue;
+
+	/* OK.  Looks like the correct import stub.  */
+	anaddr = SYMBOL_VALUE (msymbol2);
+	dld_cache.hook_stub.address = anaddr;
+      }
+  }
+  store_unsigned_integer (buf, 4, anaddr);
+
+  msymbol = lookup_minimal_symbol ("__dld_hook", NULL, symfile_objfile);
+  if (msymbol == NULL)
+    {
+      warning ("Unable to find __dld_hook symbol in object file.");
+      warning ("Suggest linking with /opt/langtools/lib/end.o.");
+      warning ("GDB will be unable to track shl_load/shl_unload calls");
+      goto keep_going;
+    }
+  anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
+  status = target_write_memory (anaddr, buf, 4);
+
+  /* Now set a shlib_event breakpoint at __d_trap so we can track
+     significant shared library events.  */
+  msymbol = lookup_minimal_symbol ("__d_trap", NULL, symfile_objfile);
+  if (msymbol == NULL)
+    {
+      warning ("Unable to find __dld_d_trap symbol in object file.");
+      warning ("Suggest linking with /opt/langtools/lib/end.o.");
+      warning ("GDB will be unable to track shl_load/shl_unload calls");
+      goto keep_going;
+    }
+  create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
+
+  /* We have all the support usually found in end.o, so we can track
+     shl_load and shl_unload calls.  */
+  have_endo = 1;
+
+keep_going:
+
+  /* Get the address of __dld_flags, if no such symbol exists, then we can
+     not debug the shared code.  */
+  msymbol = lookup_minimal_symbol ("__dld_flags", NULL, NULL);
+  if (msymbol == NULL)
+    {
+      error ("Unable to find __dld_flags symbol in object file.\n");
+    }
+
+  anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
+
+  /* Read the current contents.  */
+  status = target_read_memory (anaddr, buf, 4);
+  if (status != 0)
+    {
+      error ("Unable to read __dld_flags\n");
+    }
+  dld_flags = extract_unsigned_integer (buf, 4);
+
+  /* Turn on the flags we care about.  */
+  dld_flags |= DLD_FLAGS_MAPPRIVATE;
+  if (have_endo)
+    dld_flags |= DLD_FLAGS_HOOKVALID;
+  store_unsigned_integer (buf, 4, dld_flags);
+  status = target_write_memory (anaddr, buf, 4);
+  if (status != 0)
+    {
+      error ("Unable to write __dld_flags\n");
+    }
+
+  /* Now find the address of _start and set a breakpoint there. 
+     We still need this code for two reasons:
+
+     * Not all sites have /opt/langtools/lib/end.o, so it's not always
+     possible to track the dynamic linker's events.
+
+     * At this time no events are triggered for shared libraries
+     loaded at startup time (what a crock).  */
+
+  msymbol = lookup_minimal_symbol ("_start", NULL, symfile_objfile);
+  if (msymbol == NULL)
+    {
+      error ("Unable to find _start symbol in object file.\n");
+    }
+
+  anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
+
+  /* Make the breakpoint at "_start" a shared library event breakpoint.  */
+  create_solib_event_breakpoint (anaddr);
+
+  clear_symtab_users ();
+}
+
+/* This operation removes the "hook" between GDB and the dynamic linker,
+   which causes the dld to notify GDB of shared library events.
+
+   After this operation completes, the dld will no longer notify GDB of
+   shared library events.  To resume notifications, GDB must call
+   som_solib_create_inferior_hook.
+
+   This operation does not remove any knowledge of shared libraries which
+   GDB may already have been notified of.
+ */
+static void
+som_solib_remove_inferior_hook (int pid)
+{
+  CORE_ADDR addr;
+  struct minimal_symbol *msymbol;
+  int status;
+  char dld_flags_buffer[4];
+  unsigned int dld_flags_value;
+  struct cleanup *old_cleanups = save_inferior_ptid ();
+
+  /* Ensure that we're really operating on the specified process. */
+  inferior_ptid = pid_to_ptid (pid);
+
+  /* We won't bother to remove the solib breakpoints from this process.
+
+     In fact, on PA64 the breakpoint is hard-coded into the dld callback,
+     and thus we're not supposed to remove it.
+
+     Rather, we'll merely clear the dld_flags bit that enables callbacks.
+   */
+  msymbol = lookup_minimal_symbol ("__dld_flags", NULL, NULL);
+
+  addr = SYMBOL_VALUE_ADDRESS (msymbol);
+  status = target_read_memory (addr, dld_flags_buffer, 4);
+
+  dld_flags_value = extract_unsigned_integer (dld_flags_buffer, 4);
+
+  dld_flags_value &= ~DLD_FLAGS_HOOKVALID;
+  store_unsigned_integer (dld_flags_buffer, 4, dld_flags_value);
+  status = target_write_memory (addr, dld_flags_buffer, 4);
+
+  do_cleanups (old_cleanups);
+}
+
+static void
+som_special_symbol_handling (void)
+{
+}
+
+static void
+som_solib_desire_dynamic_linker_symbols (void)
+{
+  struct objfile *objfile;
+  struct unwind_table_entry *u;
+  struct minimal_symbol *dld_msymbol;
+
+  /* Do we already know the value of these symbols?  If so, then
+     we've no work to do.
+
+     (If you add clauses to this test, be sure to likewise update the
+     test within the loop.)
+   */
+  if (dld_cache.is_valid)
+    return;
+
+  ALL_OBJFILES (objfile)
+  {
+    dld_msymbol = lookup_minimal_symbol ("shl_load", NULL, objfile);
+    if (dld_msymbol != NULL)
+      {
+	dld_cache.load.address = SYMBOL_VALUE (dld_msymbol);
+	dld_cache.load.unwind = find_unwind_entry (dld_cache.load.address);
+      }
+
+    dld_msymbol = lookup_minimal_symbol_solib_trampoline ("shl_load",
+							  objfile);
+    if (dld_msymbol != NULL)
+      {
+	if (SYMBOL_TYPE (dld_msymbol) == mst_solib_trampoline)
+	  {
+	    u = find_unwind_entry (SYMBOL_VALUE (dld_msymbol));
+	    if ((u != NULL) && (u->stub_unwind.stub_type == EXPORT))
+	      {
+		dld_cache.load_stub.address = SYMBOL_VALUE (dld_msymbol);
+		dld_cache.load_stub.unwind = u;
+	      }
+	  }
+      }
+
+    dld_msymbol = lookup_minimal_symbol ("shl_unload", NULL, objfile);
+    if (dld_msymbol != NULL)
+      {
+	dld_cache.unload.address = SYMBOL_VALUE (dld_msymbol);
+	dld_cache.unload.unwind = find_unwind_entry (dld_cache.unload.address);
+
+	/* ??rehrauer: I'm not sure exactly what this is, but it appears
+	   that on some HPUX 10.x versions, there's two unwind regions to
+	   cover the body of "shl_unload", the second being 4 bytes past
+	   the end of the first.  This is a large hack to handle that
+	   case, but since I don't seem to have any legitimate way to
+	   look for this thing via the symbol table...
+	 */
+	if (dld_cache.unload.unwind != NULL)
+	  {
+	    u = find_unwind_entry (dld_cache.unload.unwind->region_end + 4);
+	    if (u != NULL)
+	      {
+		dld_cache.unload2.address = u->region_start;
+		dld_cache.unload2.unwind = u;
+	      }
+	  }
+      }
+
+    dld_msymbol = lookup_minimal_symbol_solib_trampoline ("shl_unload",
+							  objfile);
+    if (dld_msymbol != NULL)
+      {
+	if (SYMBOL_TYPE (dld_msymbol) == mst_solib_trampoline)
+	  {
+	    u = find_unwind_entry (SYMBOL_VALUE (dld_msymbol));
+	    if ((u != NULL) && (u->stub_unwind.stub_type == EXPORT))
+	      {
+		dld_cache.unload_stub.address = SYMBOL_VALUE (dld_msymbol);
+		dld_cache.unload_stub.unwind = u;
+	      }
+	  }
+      }
+
+    /* Did we find everything we were looking for?  If so, stop. */
+    if ((dld_cache.load.address != 0)
+	&& (dld_cache.load_stub.address != 0)
+	&& (dld_cache.unload.address != 0)
+	&& (dld_cache.unload_stub.address != 0))
+      {
+	dld_cache.is_valid = 1;
+	break;
+      }
+  }
+
+  dld_cache.hook.unwind = find_unwind_entry (dld_cache.hook.address);
+  dld_cache.hook_stub.unwind = find_unwind_entry (dld_cache.hook_stub.address);
+
+  /* We're prepared not to find some of these symbols, which is why
+     this function is a "desire" operation, and not a "require".
+   */
+}
+
+static int
+som_in_dynsym_resolve_code (CORE_ADDR pc)
+{
+  struct unwind_table_entry *u_pc;
+
+  /* Are we in the dld itself?
+
+     ??rehrauer: Large hack -- We'll assume that any address in a
+     shared text region is the dld's text.  This would obviously
+     fall down if the user attached to a process, whose shlibs
+     weren't mapped to a (writeable) private region.  However, in
+     that case the debugger probably isn't able to set the fundamental
+     breakpoint in the dld callback anyways, so this hack should be
+     safe.
+   */
+  if ((pc & (CORE_ADDR) 0xc0000000) == (CORE_ADDR) 0xc0000000)
+    return 1;
+
+  /* Cache the address of some symbols that are part of the dynamic
+     linker, if not already known.
+   */
+  som_solib_desire_dynamic_linker_symbols ();
+
+  /* Are we in the dld callback?  Or its export stub? */
+  u_pc = find_unwind_entry (pc);
+  if (u_pc == NULL)
+    return 0;
+
+  if ((u_pc == dld_cache.hook.unwind) || (u_pc == dld_cache.hook_stub.unwind))
+    return 1;
+
+  /* Or the interface of the dld (i.e., "shl_load" or friends)? */
+  if ((u_pc == dld_cache.load.unwind)
+      || (u_pc == dld_cache.unload.unwind)
+      || (u_pc == dld_cache.unload2.unwind)
+      || (u_pc == dld_cache.load_stub.unwind)
+      || (u_pc == dld_cache.unload_stub.unwind))
+    return 1;
+
+  /* Apparently this address isn't part of the dld's text. */
+  return 0;
+}
+
+static void
+som_clear_solib (void)
+{
+}
+
+struct dld_list {
+  char name[4];
+  char info[4];
+  char text_addr[4];
+  char text_link_addr[4];
+  char text_end[4];
+  char data_start[4];
+  char bss_start[4];
+  char data_end[4];
+  char got_value[4];
+  char next[4];
+  char tsd_start_addr_ptr[4];
+};
+
+static CORE_ADDR
+link_map_start (void)
+{
+  struct minimal_symbol *sym;
+  CORE_ADDR addr;
+  char buf[4];
+  unsigned int dld_flags;
+
+  sym = lookup_minimal_symbol ("__dld_flags", NULL, NULL);
+  if (!sym)
+    {
+      error ("Unable to find __dld_flags symbol in object file.\n");
+      return 0;
+    }
+  addr = SYMBOL_VALUE_ADDRESS (sym);
+  read_memory (addr, buf, 4);
+  dld_flags = extract_unsigned_integer (buf, 4);
+  if ((dld_flags & DLD_FLAGS_LISTVALID) == 0)
+    {
+      error ("__dld_list is not valid according to __dld_flags.\n");
+      return 0;
+    }
+
+  /* If the libraries were not mapped private, warn the user.  */
+  if ((dld_flags & DLD_FLAGS_MAPPRIVATE) == 0)
+    warning ("The shared libraries were not privately mapped; setting a\n"
+	     "breakpoint in a shared library will not work until you rerun the "
+	     "program.\n");
+
+  sym = lookup_minimal_symbol ("__dld_list", NULL, NULL);
+  if (!sym)
+    {
+      /* Older crt0.o files (hpux8) don't have __dld_list as a symbol,
+         but the data is still available if you know where to look.  */
+      sym = lookup_minimal_symbol ("__dld_flags", NULL, NULL);
+      if (!sym)
+	{
+	  error ("Unable to find dynamic library list.\n");
+	  return 0;
+	}
+      addr = SYMBOL_VALUE_ADDRESS (sym) - 8;
+    }
+  else
+    addr = SYMBOL_VALUE_ADDRESS (sym);
+
+  read_memory (addr, buf, 4);
+  addr = extract_unsigned_integer (buf, 4);
+  if (addr == 0)
+    {
+      error ("Debugging dynamic executables loaded via the hpux8 dld.sl is not supported.\n");
+      return 0;
+    }
+
+  read_memory (addr, buf, 4);
+  return extract_unsigned_integer (buf, 4);
+}
+
+/* Does this so's name match the main binary? */
+static int
+match_main (const char *name)
+{
+  return strcmp (name, symfile_objfile->name) == 0;
+}
+
+static struct so_list *
+som_current_sos (void)
+{
+  CORE_ADDR lm;
+  struct so_list *head = 0;
+  struct so_list **link_ptr = &head;
+
+  for (lm = link_map_start (); lm; )
+    {
+      char *namebuf;
+      CORE_ADDR addr;
+      struct so_list *new;
+      struct cleanup *old_chain;
+      int errcode;
+      struct dld_list dbuf;
+      char tsdbuf[4];
+
+      new = (struct so_list *) xmalloc (sizeof (struct so_list));
+      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);
+
+      read_memory (lm, (char *)&dbuf, sizeof (struct dld_list));
+
+      addr = extract_unsigned_integer (&dbuf.name, sizeof (dbuf.name));
+      target_read_string (addr, &namebuf, 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, namebuf, SO_NAME_MAX_PATH_SIZE - 1);
+	  new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
+	  xfree (namebuf);
+	  strcpy (new->so_original_name, new->so_name);
+	}
+
+	if (new->so_name[0] && !match_main (new->so_name))
+	  {
+	    struct lm_info *lmi = new->lm_info;
+	    unsigned int tmp;
+
+	    lmi->lm_addr = lm;
+
+#define EXTRACT(_fld) \
+  extract_unsigned_integer (&dbuf._fld, sizeof (dbuf._fld));
+
+	    lmi->text_addr = EXTRACT (text_addr);
+	    tmp = EXTRACT (info);
+	    lmi->library_version = (tmp >> 16) & 0xffff;
+	    lmi->bind_mode = (tmp >> 8) & 0xff;
+	    lmi->struct_version = tmp & 0xff;
+	    lmi->text_link_addr = EXTRACT (text_link_addr);
+	    lmi->text_end = EXTRACT (text_end);
+	    lmi->data_start = EXTRACT (data_start);
+	    lmi->bss_start = EXTRACT (bss_start);
+	    lmi->data_end = EXTRACT (data_end);
+	    lmi->got_value = EXTRACT (got_value);
+	    tmp = EXTRACT (tsd_start_addr_ptr);
+	    read_memory (tmp, tsdbuf, 4);
+	    lmi->tsd_start_addr = extract_unsigned_integer (tsdbuf, 4);
+
+#ifdef SOLIB_SOM_DBG
+	    printf ("\n+ library \"%s\" is described at 0x%s\n", new->so_name, 
+	    	    paddr_nz (lm));
+	    printf ("  'version' is %d\n", new->lm_info->struct_version);
+	    printf ("  'bind_mode' is %d\n", new->lm_info->bind_mode);
+	    printf ("  'library_version' is %d\n", 
+	    	    new->lm_info->library_version);
+	    printf ("  'text_addr' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->text_addr));
+	    printf ("  'text_link_addr' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->text_link_addr));
+	    printf ("  'text_end' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->text_end));
+	    printf ("  'data_start' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->data_start));
+	    printf ("  'bss_start' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->bss_start));
+	    printf ("  'data_end' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->data_end));
+	    printf ("  'got_value' is %s\n", 
+	    	    paddr_nz (new->lm_info->got_value));
+	    printf ("  'tsd_start_addr' is 0x%s\n", 
+	    	    paddr_nz (new->lm_info->tsd_start_addr));
+#endif
+
+	    /* Link the new object onto the list.  */
+	    new->next = NULL;
+	    *link_ptr = new;
+	    link_ptr = &new->next;
+	  }
+ 	else
+	  {
+	    free_so (new);
+	  }
+
+      lm = EXTRACT (next);
+      discard_cleanups (old_chain);
+#undef EXTRACT
+    }
+
+  /* TODO: The original somsolib code has logic to detect and eliminate 
+     duplicate entries.  Do we need that?  */
+
+  return head;
+}
+
+static int
+som_open_symbol_file_object (void *from_ttyp)
+{
+  CORE_ADDR lm, l_name;
+  char *filename;
+  int errcode;
+  int from_tty = *(int *)from_ttyp;
+  char buf[4];
+
+  if (symfile_objfile)
+    if (!query ("Attempt to reload symbols from process? "))
+      return 0;
+
+  /* First link map member should be the executable.  */
+  if ((lm = link_map_start ()) == 0)
+    return 0;	/* failed somehow... */
+
+  /* Read address of name from target memory to GDB.  */
+  read_memory (lm + offsetof (struct dld_list, name), buf, 4);
+
+  /* Convert the address to host format.  Assume that the address is
+     unsigned.  */
+  l_name = extract_unsigned_integer (buf, 4);
+
+  if (l_name == 0)
+    return 0;		/* No filename.  */
+
+  /* Now fetch the filename from target memory.  */
+  target_read_string (l_name, &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;
+    }
+
+  make_cleanup (xfree, filename);
+  /* Have a pathname: read the symbol file.  */
+  symbol_file_add_main (filename, from_tty);
+
+  return 1;
+}
+
+static void
+som_free_so (struct so_list *so)
+{
+  xfree (so->lm_info);
+}
+
+static CORE_ADDR
+som_solib_thread_start_addr (struct so_list *so)
+{
+  return so->lm_info->tsd_start_addr;
+}
+
+/* Return the GOT value for the shared library in which ADDR belongs.  If
+   ADDR isn't in any known shared library, return zero.  */
+
+static CORE_ADDR
+som_solib_get_got_by_pc (CORE_ADDR addr)
+{
+  struct so_list *so_list = master_so_list ();
+  CORE_ADDR got_value = 0;
+
+  while (so_list)
+    {
+      if (so_list->lm_info->text_addr <= addr
+	  && so_list->lm_info->text_end > addr)
+	{
+	  got_value = so_list->lm_info->got_value;
+	  break;
+	}
+      so_list = so_list->next;
+    }
+  return got_value;
+}
+
+/* Return the address of the handle of the shared library in which ADDR belongs.
+   If ADDR isn't in any known shared library, return zero.  */
+/* this function is used in initialize_hp_cxx_exception_support in 
+   hppa-hpux-tdep.c  */
+
+static CORE_ADDR
+som_solib_get_solib_by_pc (CORE_ADDR addr)
+{
+  struct so_list *so_list = master_so_list ();
+
+  while (so_list)
+    {
+      if (so_list->lm_info->text_addr <= addr
+	  && so_list->lm_info->text_end > addr)
+	{
+	  break;
+	}
+      so_list = so_list->next;
+    }
+  if (so_list)
+    return so_list->lm_info->lm_addr;
+  else
+    return 0;
+}
+
+
+static struct target_so_ops som_so_ops;
+
+extern initialize_file_ftype _initialize_som_solib; /* -Wmissing-prototypes */
+
+void
+_initialize_som_solib (void)
+{
+  som_so_ops.relocate_section_addresses = som_relocate_section_addresses;
+  som_so_ops.free_so = som_free_so;
+  som_so_ops.clear_solib = som_clear_solib;
+  som_so_ops.solib_create_inferior_hook = som_solib_create_inferior_hook;
+  som_so_ops.special_symbol_handling = som_special_symbol_handling;
+  som_so_ops.current_sos = som_current_sos;
+  som_so_ops.open_symbol_file_object = som_open_symbol_file_object;
+  som_so_ops.in_dynsym_resolve_code = som_in_dynsym_resolve_code;
+}
+
+void som_solib_select (struct gdbarch_tdep *tdep)
+{
+  current_target_so_ops = &som_so_ops;
+
+  tdep->solib_thread_start_addr = som_solib_thread_start_addr;
+  tdep->solib_get_got_by_pc = som_solib_get_got_by_pc;
+  tdep->solib_get_solib_by_pc = som_solib_get_solib_by_pc;
+}
+
+/* The rest of these functions are not part of the solib interface; they 
+   are used by somread.c or hppa-hpux-tdep.c */
+
+int
+som_solib_section_offsets (struct objfile *objfile,
+			   struct section_offsets *offsets)
+{
+  struct so_list *so_list = master_so_list ();
+
+  while (so_list)
+    {
+      /* Oh what a pain!  We need the offsets before so_list->objfile
+         is valid.  The BFDs will never match.  Make a best guess.  */
+      if (strstr (objfile->name, so_list->so_name))
+	{
+	  asection *private_section;
+
+	  /* The text offset is easy.  */
+	  offsets->offsets[SECT_OFF_TEXT (objfile)]
+	    = (so_list->lm_info->text_addr
+	       - so_list->lm_info->text_link_addr);
+	  offsets->offsets[SECT_OFF_RODATA (objfile)]
+	    = ANOFFSET (offsets, SECT_OFF_TEXT (objfile));
+
+	  /* We should look at presumed_dp in the SOM header, but
+	     that's not easily available.  This should be OK though.  */
+	  private_section = bfd_get_section_by_name (objfile->obfd,
+						     "$PRIVATE$");
+	  if (!private_section)
+	    {
+	      warning ("Unable to find $PRIVATE$ in shared library!");
+	      offsets->offsets[SECT_OFF_DATA (objfile)] = 0;
+	      offsets->offsets[SECT_OFF_BSS (objfile)] = 0;
+	      return 1;
+	    }
+	  offsets->offsets[SECT_OFF_DATA (objfile)]
+	    = (so_list->lm_info->data_start - private_section->vma);
+	  offsets->offsets[SECT_OFF_BSS (objfile)]
+	    = ANOFFSET (offsets, SECT_OFF_DATA (objfile));
+	  return 1;
+	}
+      so_list = so_list->next;
+    }
+  return 0;
+}