* irix5-nat.c: Move IRIX shared library support from here...

	* solib-irix.c: ...to here.  Revised substantially to work with
	generic solib framework.

1 files changed, 725 insertions, 0 deletions

diff --git a/gdb/solib-irix.c b/gdb/solib-irix.c
new file mode 100644
index 00000000000..1cfa452b06d
--- /dev/null
+++ b/gdb/solib-irix.c
@@ -0,0 +1,725 @@
+/* Shared library support for IRIX.
+   Copyright 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002
+   Free Software Foundation, Inc.
+
+   This file was created using portions of irix5-nat.c originally
+   contributed to GDB by Ian Lance Taylor.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 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 "symtab.h"
+#include "bfd.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "gdbcore.h"
+#include "target.h"
+#include "inferior.h"
+
+#include "solist.h"
+
+/* Link map info to include in an allocate so_list entry.  Unlike some
+   of the other solib backends, this (Irix) backend chooses to decode
+   the link map info obtained from the target and store it as (mostly)
+   CORE_ADDRs which need no further decoding.  This is more convenient
+   because there are three different link map formats to worry about.
+   We use a single routine (fetch_lm_info) to read (and decode) the target
+   specific link map data.  */
+
+struct lm_info
+{
+  CORE_ADDR addr;		/* address of obj_info or obj_list
+				   struct on target (from which the
+				   following information is obtained).  */
+  CORE_ADDR next;		/* address of next item in list.  */
+  CORE_ADDR reloc_offset;	/* amount to relocate by  */
+  CORE_ADDR pathname_addr;	/* address of pathname  */
+  int pathname_len;		/* length of pathname */
+};
+
+/* It's not desirable to use the system header files to obtain the
+   structure of the obj_list or obj_info structs.  Therefore, we use a
+   platform neutral representation which has been derived from the IRIX
+   header files.  */
+
+typedef struct
+{
+  char b[4];
+}
+gdb_int32_bytes;
+typedef struct
+{
+  char b[8];
+}
+gdb_int64_bytes;
+
+/* The "old" obj_list struct.  This is used with old (o32) binaries.
+   The ``data'' member points at a much larger and more complicated
+   struct which we will only refer to by offsets.  See
+   fetch_lm_info().  */
+
+struct irix_obj_list
+{
+  gdb_int32_bytes data;
+  gdb_int32_bytes next;
+  gdb_int32_bytes prev;
+};
+
+/* The ELF32 and ELF64 versions of the above struct.  The oi_magic value
+   corresponds to the ``data'' value in the "old" struct.  When this value
+   is 0xffffffff, the data will be in one of the following formats.  The
+   ``oi_size'' field is used to decide which one we actually have.  */
+
+struct irix_elf32_obj_info
+{
+  gdb_int32_bytes oi_magic;
+  gdb_int32_bytes oi_size;
+  gdb_int32_bytes oi_next;
+  gdb_int32_bytes oi_prev;
+  gdb_int32_bytes oi_ehdr;
+  gdb_int32_bytes oi_orig_ehdr;
+  gdb_int32_bytes oi_pathname;
+  gdb_int32_bytes oi_pathname_len;
+};
+
+struct irix_elf64_obj_info
+{
+  gdb_int32_bytes oi_magic;
+  gdb_int32_bytes oi_size;
+  gdb_int64_bytes oi_next;
+  gdb_int64_bytes oi_prev;
+  gdb_int64_bytes oi_ehdr;
+  gdb_int64_bytes oi_orig_ehdr;
+  gdb_int64_bytes oi_pathname;
+  gdb_int32_bytes oi_pathname_len;
+  gdb_int32_bytes padding;
+};
+
+/* Union of all of the above (plus a split out magic field).  */
+
+union irix_obj_info
+{
+  gdb_int32_bytes magic;
+  struct irix_obj_list ol32;
+  struct irix_elf32_obj_info oi32;
+  struct irix_elf64_obj_info oi64;
+};
+
+/* MIPS sign extends its 32 bit addresses.  We could conceivably use
+   extract_typed_address here, but to do so, we'd have to construct an
+   appropriate type.  Calling extract_signed_integer or
+   extract_address seems simpler.  */
+
+static CORE_ADDR
+extract_mips_address (void *addr, int len)
+{
+  if (len <= 32)
+    return extract_signed_integer (addr, len);
+  else
+    return extract_address (addr, len);
+}
+
+/* Fetch and return the link map data associated with ADDR.  Note that
+   this routine automatically determines which (of three) link map
+   formats is in use by the target.  */
+
+struct lm_info
+fetch_lm_info (CORE_ADDR addr)
+{
+  struct lm_info li;
+  union irix_obj_info buf;
+
+  li.addr = addr;
+
+  /* The smallest region that we'll need is for buf.ol32.  We'll read
+     that first.  We'll read more of the buffer later if we have to deal
+     with one of the other cases.  (We don't want to incur a memory error
+     if we were to read a larger region that generates an error due to
+     being at the end of a page or the like.)  */
+  read_memory (addr, (char *) &buf, sizeof (buf.ol32));
+
+  if (extract_unsigned_integer (&buf.magic, sizeof (buf.magic)) != 0xffffffff)
+    {
+      /* Use buf.ol32... */
+      char obj_buf[432];
+      CORE_ADDR obj_addr = extract_mips_address (&buf.ol32.data,
+						 sizeof (buf.ol32.data));
+      li.next = extract_mips_address (&buf.ol32.next, sizeof (buf.ol32.next));
+
+      read_memory (obj_addr, obj_buf, sizeof (obj_buf));
+
+      li.pathname_addr = extract_mips_address (&obj_buf[236], 4);
+      li.pathname_len = 0;	/* unknown */
+      li.reloc_offset = extract_mips_address (&obj_buf[196], 4)
+	- extract_mips_address (&obj_buf[248], 4);
+
+    }
+  else if (extract_unsigned_integer (&buf.oi32.oi_size,
+				     sizeof (buf.oi32.oi_size))
+	   == sizeof (buf.oi32))
+    {
+      /* Use buf.oi32...  */
+
+      /* Read rest of buffer.  */
+      read_memory (addr + sizeof (buf.ol32),
+		   ((char *) &buf) + sizeof (buf.ol32),
+		   sizeof (buf.oi32) - sizeof (buf.ol32));
+
+      /* Fill in fields using buffer contents.  */
+      li.next = extract_mips_address (&buf.oi32.oi_next,
+				      sizeof (buf.oi32.oi_next));
+      li.reloc_offset = extract_mips_address (&buf.oi32.oi_ehdr,
+					      sizeof (buf.oi32.oi_ehdr))
+	- extract_mips_address (&buf.oi32.oi_orig_ehdr,
+				sizeof (buf.oi32.oi_orig_ehdr));
+      li.pathname_addr = extract_mips_address (&buf.oi32.oi_pathname,
+					       sizeof (buf.oi32.oi_pathname));
+      li.pathname_len = extract_unsigned_integer (&buf.oi32.oi_pathname_len,
+						  sizeof (buf.oi32.
+							  oi_pathname_len));
+    }
+  else if (extract_unsigned_integer (&buf.oi64.oi_size,
+				     sizeof (buf.oi64.oi_size))
+	   == sizeof (buf.oi64))
+    {
+      /* Use buf.oi64...  */
+
+      /* Read rest of buffer.  */
+      read_memory (addr + sizeof (buf.ol32),
+		   ((char *) &buf) + sizeof (buf.ol32),
+		   sizeof (buf.oi64) - sizeof (buf.ol32));
+
+      /* Fill in fields using buffer contents.  */
+      li.next = extract_mips_address (&buf.oi64.oi_next,
+				      sizeof (buf.oi64.oi_next));
+      li.reloc_offset = extract_mips_address (&buf.oi64.oi_ehdr,
+					      sizeof (buf.oi64.oi_ehdr))
+	- extract_mips_address (&buf.oi64.oi_orig_ehdr,
+				sizeof (buf.oi64.oi_orig_ehdr));
+      li.pathname_addr = extract_mips_address (&buf.oi64.oi_pathname,
+					       sizeof (buf.oi64.oi_pathname));
+      li.pathname_len = extract_unsigned_integer (&buf.oi64.oi_pathname_len,
+						  sizeof (buf.oi64.
+							  oi_pathname_len));
+    }
+  else
+    {
+      error ("Unable to fetch shared library obj_info or obj_list info.");
+    }
+
+  return li;
+}
+
+/* The symbol which starts off the list of shared libraries.  */
+#define DEBUG_BASE "__rld_obj_head"
+
+char shadow_contents[BREAKPOINT_MAX];	/* Stash old bkpt addr contents */
+
+static CORE_ADDR debug_base;	/* Base of dynamic linker structures */
+static CORE_ADDR breakpoint_addr;	/* Address where end bkpt is set */
+
+/*
+
+   LOCAL FUNCTION
+
+   locate_base -- locate the base address of dynamic linker structs
+
+   SYNOPSIS
+
+   CORE_ADDR locate_base (void)
+
+   DESCRIPTION
+
+   For both the SunOS and SVR4 shared library implementations, if the
+   inferior executable has been linked dynamically, there is a single
+   address somewhere in the inferior's data space which is the key to
+   locating all of the dynamic linker's runtime structures.  This
+   address is the value of the symbol defined by the macro DEBUG_BASE.
+   The job of this function is to find and return that address, or to
+   return 0 if there is no such address (the executable is statically
+   linked for example).
+
+   For SunOS, the job is almost trivial, since the dynamic linker and
+   all of it's structures are statically linked to the executable at
+   link time.  Thus the symbol for the address we are looking for has
+   already been added to the minimal symbol table for the executable's
+   objfile at the time the symbol file's symbols were read, and all we
+   have to do is look it up there.  Note that we explicitly do NOT want
+   to find the copies in the shared library.
+
+   The SVR4 version is much more complicated because the dynamic linker
+   and it's structures are located in the shared C library, which gets
+   run as the executable's "interpreter" by the kernel.  We have to go
+   to a lot more work to discover the address of DEBUG_BASE.  Because
+   of this complexity, we cache the value we find and return that value
+   on subsequent invocations.  Note there is no copy in the executable
+   symbol tables.
+
+   Irix 5 is basically like SunOS.
+
+   Note that we can assume nothing about the process state at the time
+   we need to find this address.  We may be stopped on the first instruc-
+   tion of the interpreter (C shared library), the first instruction of
+   the executable itself, or somewhere else entirely (if we attached
+   to the process for example).
+
+ */
+
+static CORE_ADDR
+locate_base (void)
+{
+  struct minimal_symbol *msymbol;
+  CORE_ADDR address = 0;
+
+  msymbol = lookup_minimal_symbol (DEBUG_BASE, NULL, symfile_objfile);
+  if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
+    {
+      address = SYMBOL_VALUE_ADDRESS (msymbol);
+    }
+  return (address);
+}
+
+/*
+
+   LOCAL FUNCTION
+
+   disable_break -- remove the "mapping changed" breakpoint
+
+   SYNOPSIS
+
+   static int disable_break ()
+
+   DESCRIPTION
+
+   Removes the breakpoint that gets hit when the dynamic linker
+   completes a mapping change.
+
+ */
+
+static int
+disable_break (void)
+{
+  int status = 1;
+
+
+  /* Note that breakpoint address and original contents are in our address
+     space, so we just need to write the original contents back. */
+
+  if (memory_remove_breakpoint (breakpoint_addr, shadow_contents) != 0)
+    {
+      status = 0;
+    }
+
+  /* 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 (status);
+}
+
+/*
+
+   LOCAL FUNCTION
+
+   enable_break -- arrange for dynamic linker to hit breakpoint
+
+   SYNOPSIS
+
+   int enable_break (void)
+
+   DESCRIPTION
+
+   This functions inserts a breakpoint at the entry point of the
+   main executable, where all shared libraries are mapped in.
+ */
+
+static int
+enable_break (void)
+{
+  if (symfile_objfile != NULL
+      && target_insert_breakpoint (symfile_objfile->ei.entry_point,
+				   shadow_contents) == 0)
+    {
+      breakpoint_addr = symfile_objfile->ei.entry_point;
+      return 1;
+    }
+
+  return 0;
+}
+
+/*
+
+   LOCAL FUNCTION
+
+   irix_solib_create_inferior_hook -- shared library startup support
+
+   SYNOPSIS
+
+   void 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
+irix_solib_create_inferior_hook (void)
+{
+  if (!enable_break ())
+    {
+      warning ("shared library handler failed to enable breakpoint");
+      return;
+    }
+
+  /* Now run the target.  It will eventually hit the breakpoint, at
+     which point all of the libraries will have been mapped in and we
+     can go groveling around in the dynamic linker structures to find
+     out what we need to know about them. */
+
+  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);
+
+  /* We are now either at the "mapping complete" breakpoint (or somewhere
+     else, a condition we aren't prepared to deal with anyway), so adjust
+     the PC as necessary after a breakpoint, disable the breakpoint, and
+     add any shared libraries that were mapped in. */
+
+  if (!disable_break ())
+    {
+      warning ("shared library handler failed to disable breakpoint");
+    }
+
+  /* solib_add will call reinit_frame_cache.
+     But we are stopped in the startup code and we might not have symbols
+     for the startup code, so heuristic_proc_start could be called
+     and will put out an annoying warning.
+     Delaying the resetting of stop_soon_quietly until after symbol loading
+     suppresses the warning.  */
+  solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
+  stop_soon_quietly = 0;
+  re_enable_breakpoints_in_shlibs ();
+}
+
+/* LOCAL FUNCTION
+
+   current_sos -- build a list of currently loaded shared objects
+
+   SYNOPSIS
+
+   struct so_list *current_sos ()
+
+   DESCRIPTION
+
+   Build a list of `struct so_list' objects describing the shared
+   objects currently loaded in the inferior.  This list does not
+   include an entry for the main executable file.
+
+   Note that we only gather information directly available from the
+   inferior --- we don't examine any of the shared library files
+   themselves.  The declaration of `struct so_list' says which fields
+   we provide values for.  */
+
+static struct so_list *
+irix_current_sos (void)
+{
+  CORE_ADDR lma;
+  char addr_buf[8];
+  struct so_list *head = 0;
+  struct so_list **link_ptr = &head;
+  int is_first = 1;
+  struct lm_info lm;
+
+  /* Make sure we've looked up the inferior's dynamic linker's base
+     structure.  */
+  if (!debug_base)
+    {
+      debug_base = locate_base ();
+
+      /* If we can't find the dynamic linker's base structure, this
+         must not be a dynamically linked executable.  Hmm.  */
+      if (!debug_base)
+	return 0;
+    }
+
+  read_memory (debug_base, addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+  lma = extract_mips_address (addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+
+  while (lma)
+    {
+      lm = fetch_lm_info (lma);
+      if (!is_first)
+	{
+	  int errcode;
+	  char *name_buf;
+	  int name_size;
+	  struct so_list *new
+	    = (struct so_list *) xmalloc (sizeof (struct so_list));
+	  struct cleanup *old_chain = make_cleanup (xfree, new);
+
+	  memset (new, 0, sizeof (*new));
+
+	  new->lm_info = xmalloc (sizeof (struct lm_info));
+	  make_cleanup (xfree, new->lm_info);
+
+	  *new->lm_info = lm;
+
+	  /* Extract this shared object's name.  */
+	  name_size = lm.pathname_len;
+	  if (name_size == 0)
+	    name_size = SO_NAME_MAX_PATH_SIZE - 1;
+
+	  if (name_size >= SO_NAME_MAX_PATH_SIZE)
+	    {
+	      name_size = SO_NAME_MAX_PATH_SIZE - 1;
+	      warning
+		("current_sos: truncating name of %d characters to only %d characters",
+		 lm.pathname_len, name_size);
+	    }
+
+	  target_read_string (lm.pathname_addr, &name_buf,
+			      name_size, &errcode);
+	  if (errcode != 0)
+	    {
+	      warning ("current_sos: Can't read pathname for load map: %s\n",
+		       safe_strerror (errcode));
+	    }
+	  else
+	    {
+	      strncpy (new->so_name, name_buf, name_size);
+	      new->so_name[name_size] = '\0';
+	      xfree (name_buf);
+	      strcpy (new->so_original_name, new->so_name);
+	    }
+
+	  new->next = 0;
+	  *link_ptr = new;
+	  link_ptr = &new->next;
+
+	  discard_cleanups (old_chain);
+	}
+      is_first = 0;
+      lma = lm.next;
+    }
+
+  return head;
+}
+
+/*
+
+  LOCAL FUNCTION
+
+  irix_open_symbol_file_object
+
+  SYNOPSIS
+
+  void irix_open_symbol_file_object (void *from_tty)
+
+  DESCRIPTION
+
+  If no open symbol file, attempt to locate and open the main symbol
+  file.  On IRIX, this is the first link map entry.  If its name is
+  here, we can open it.  Useful when attaching to a process without
+  first loading its symbol file.
+
+  If FROM_TTYP dereferences to a non-zero integer, allow messages to
+  be printed.  This parameter is a pointer rather than an int because
+  open_symbol_file_object() is called via catch_errors() and
+  catch_errors() requires a pointer argument. */
+
+static int
+irix_open_symbol_file_object (void *from_ttyp)
+{
+  CORE_ADDR lma;
+  char addr_buf[8];
+  struct lm_info lm;
+  struct cleanup *cleanups;
+  int errcode;
+  int from_tty = *(int *) from_ttyp;
+  char *filename;
+
+  if (symfile_objfile)
+    if (!query ("Attempt to reload symbols from process? "))
+      return 0;
+
+  if ((debug_base = locate_base ()) == 0)
+    return 0;			/* failed somehow...  */
+
+  /* First link map member should be the executable.  */
+  read_memory (debug_base, addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+  lma = extract_mips_address (addr_buf, TARGET_ADDR_BIT / TARGET_CHAR_BIT);
+  if (lma == 0)
+    return 0;			/* failed somehow...  */
+
+  lm = fetch_lm_info (lma);
+
+  if (lm.pathname_addr == 0)
+    return 0;			/* No filename.  */
+
+  /* Now fetch the filename from target memory.  */
+  target_read_string (lm.pathname_addr, &filename, SO_NAME_MAX_PATH_SIZE - 1,
+		      &errcode);
+
+  if (errcode)
+    {
+      warning ("failed to read exec filename from attached file: %s",
+	       safe_strerror (errcode));
+      return 0;
+    }
+
+  cleanups = make_cleanup (xfree, filename);
+  /* Have a pathname: read the symbol file.  */
+  symbol_file_add_main (filename, from_tty);
+
+  do_cleanups (cleanups);
+
+  return 1;
+}
+
+
+/*
+
+   LOCAL FUNCTION
+
+   irix_special_symbol_handling -- additional shared library symbol handling
+
+   SYNOPSIS
+
+   void irix_special_symbol_handling ()
+
+   DESCRIPTION
+
+   Once the symbols from a shared object have been loaded in the usual
+   way, we are called to do any system specific symbol handling that 
+   is needed.
+
+   For SunOS4, this consisted of grunging around in the dynamic
+   linkers structures to find symbol definitions for "common" symbols
+   and adding them to the minimal symbol table for the runtime common
+   objfile.
+
+   However, for IRIX, there's nothing to do.
+
+ */
+
+static void
+irix_special_symbol_handling (void)
+{
+}
+
+/* Using the solist entry SO, relocate the addresses in SEC.  */
+
+static void
+irix_relocate_section_addresses (struct so_list *so,
+				 struct section_table *sec)
+{
+  sec->addr += so->lm_info->reloc_offset;
+  sec->endaddr += so->lm_info->reloc_offset;
+}
+
+/* Free the lm_info struct.  */
+
+static void
+irix_free_so (struct so_list *so)
+{
+  xfree (so->lm_info);
+}
+
+/* Clear backend specific state.  */
+
+static void
+irix_clear_solib (void)
+{
+  debug_base = 0;
+}
+
+/* Return 1 if PC lies in the dynamic symbol resolution code of the
+   run time loader.  */
+static int
+irix_in_dynsym_resolve_code (CORE_ADDR pc)
+{
+  return 0;
+}
+
+static struct target_so_ops irix_so_ops;
+
+void
+_initialize_irix_solib (void)
+{
+  irix_so_ops.relocate_section_addresses = irix_relocate_section_addresses;
+  irix_so_ops.free_so = irix_free_so;
+  irix_so_ops.clear_solib = irix_clear_solib;
+  irix_so_ops.solib_create_inferior_hook = irix_solib_create_inferior_hook;
+  irix_so_ops.special_symbol_handling = irix_special_symbol_handling;
+  irix_so_ops.current_sos = irix_current_sos;
+  irix_so_ops.open_symbol_file_object = irix_open_symbol_file_object;
+  irix_so_ops.in_dynsym_resolve_code = irix_in_dynsym_resolve_code;
+
+  /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops. */
+  current_target_so_ops = &irix_so_ops;
+}