626 lines
18 KiB
C
626 lines
18 KiB
C
/* Handle HP SOM shared libraries for GDB, the GNU Debugger.
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Copyright 1993 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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Written by the Center for Software Science at the Univerity of Utah
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and by Cygnus Support. */
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#include "defs.h"
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#include "frame.h"
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#include "bfd.h"
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#include "som.h"
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#include "libhppa.h"
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#include "gdbcore.h"
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#include "symtab.h"
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#include "breakpoint.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "inferior.h"
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/* TODO:
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* Relocate data addresses in the shared library.
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* Most of this code should work for hp300 shared libraries. Does
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anyone care enough to weed out any SOM-isms.
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* Do we need/want a command to load a shared library?
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* Support for hpux8 dynamic linker.
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* Support for tracking user calls to dld_load, dld_unload. */
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/* The basic structure which describes a dynamically loaded object. This
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data structure is private to the dynamic linker and isn't found in
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any HPUX include file. */
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struct som_solib_mapped_entry
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{
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/* The name of the library. */
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char *name;
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/* Version of this structure (it is expected to change again in hpux10). */
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unsigned char struct_version;
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/* Binding mode for this library. */
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unsigned char bind_mode;
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/* Version of this library. */
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short library_version;
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/* Start of text address, link-time text location, end of text address. */
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CORE_ADDR text_addr;
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CORE_ADDR text_link_addr;
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CORE_ADDR text_end;
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/* Start of data, start of bss and end of data. */
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CORE_ADDR data_start;
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CORE_ADDR bss_start;
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CORE_ADDR data_end;
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/* Value of linkage pointer (%r19). */
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CORE_ADDR got_value;
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/* Next entry. */
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struct som_solib_mapped_entry *next;
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/* There are other fields, but I don't have information as to what is
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contained in them. */
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};
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/* A structure to keep track of all the known shared objects. */
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struct so_list
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{
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struct som_solib_mapped_entry som_solib;
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struct objfile *objfile;
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bfd *abfd;
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struct section_table *sections;
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struct section_table *sections_end;
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struct so_list *next;
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};
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static struct so_list *so_list_head;
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static void som_sharedlibrary_info_command PARAMS ((char *, int));
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/* Add symbols from shared libraries into the symtab list. */
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void
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som_solib_add (arg_string, from_tty, target)
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char *arg_string;
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int from_tty;
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struct target_ops *target;
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{
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struct minimal_symbol *msymbol;
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struct so_list *so_list_tail;
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CORE_ADDR addr;
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asection *shlib_info;
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int status;
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unsigned int dld_flags;
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char buf[4];
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/* If we're debugging a core file, or have attached to a running
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process, then som_solib_create_inferior_hook will not have been
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called.
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We need to first determine if we're dealing with a dynamically
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linked executable. If not, then return without an error or warning.
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We also need to examine __dld_flags to determine if the shared library
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list is valid and to determine if the libraries have been privately
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mapped. */
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if (symfile_objfile == NULL)
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return;
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/* First see if the objfile was dynamically linked. */
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shlib_info = bfd_get_section_by_name (symfile_objfile->obfd, "$SHLIB_INFO$");
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if (!shlib_info)
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return;
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/* It's got a $SHLIB_INFO$ section, make sure it's not empty. */
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if (bfd_section_size (symfile_objfile->obfd, shlib_info) == 0)
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return;
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msymbol = lookup_minimal_symbol ("__dld_flags", (struct objfile *) NULL);
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if (msymbol == NULL)
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{
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error ("Unable to find __dld_flags symbol in object file.\n");
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return;
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}
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addr = SYMBOL_VALUE_ADDRESS (msymbol);
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/* Read the current contents. */
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status = target_read_memory (addr, buf, 4);
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if (status != 0)
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{
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error ("Unable to read __dld_flags\n");
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return;
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}
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dld_flags = extract_unsigned_integer (buf, 4);
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/* __dld_list may not be valid. If it's not valid tell the user. */
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if ((dld_flags & 4) == 0)
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{
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error ("__dld_list is not valid according to __dld_flags.\n");
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return;
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}
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/* If the libraries were not mapped private, warn the user. */
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if ((dld_flags & 1) == 0)
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warning ("The shared libraries were not privately mapped; setting a\nbreakpoint in a shared library will not work until you rerun the program.\n");
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msymbol = lookup_minimal_symbol ("__dld_list", (struct objfile *) NULL);
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if (!msymbol)
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{
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/* Older crt0.o files (hpux8) don't have __dld_list as a symbol,
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but the data is still available if you know where to look. */
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msymbol = lookup_minimal_symbol ("__dld_flags", (struct objfile *)NULL);
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if (!msymbol)
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{
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error ("Unable to find dynamic library list.\n");
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return;
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}
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addr = SYMBOL_VALUE_ADDRESS (msymbol) - 8;
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}
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else
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addr = SYMBOL_VALUE_ADDRESS (msymbol);
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status = target_read_memory (addr, buf, 4);
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if (status != 0)
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{
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error ("Unable to find dynamic library list.\n");
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return;
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}
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addr = extract_unsigned_integer (buf, 4);
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/* If addr is zero, then we're using an old dynamic loader which
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doesn't maintain __dld_list. We'll have to use a completely
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different approach to get shared library information. */
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if (addr == 0)
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goto old_dld;
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/* Using the information in __dld_list is the preferred method
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to get at shared library information. It doesn't depend on
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any functions in /usr/lib/end.o and has a chance of working
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with hpux10 when it is released. */
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status = target_read_memory (addr, buf, 4);
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if (status != 0)
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{
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error ("Unable to find dynamic library list.\n");
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return;
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}
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/* addr now holds the address of the first entry in the dynamic
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library list. */
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addr = extract_unsigned_integer (buf, 4);
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/* Now that we have a pointer to the dynamic library list, walk
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through it and add the symbols for each library.
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Skip the first entry since it's our executable. */
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status = target_read_memory (addr + 36, buf, 4);
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if (status != 0)
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goto err;
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addr = extract_unsigned_integer (buf, 4);
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so_list_tail = so_list_head;
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/* Find the end of the list of shared objects. */
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while (so_list_tail && so_list_tail->next)
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so_list_tail = so_list_tail->next;
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while (1)
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{
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CORE_ADDR name_addr, text_addr;
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unsigned int name_len;
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char *name;
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struct so_list *new_so;
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struct section_table *p;
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if (addr == 0)
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break;
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/* Get a pointer to the name of this library. */
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status = target_read_memory (addr, buf, 4);
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if (status != 0)
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goto err;
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name_addr = extract_unsigned_integer (buf, 4);
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name_len = 0;
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while (1)
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{
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target_read_memory (name_addr + name_len, buf, 1);
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if (status != 0)
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goto err;
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name_len++;
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if (*buf == '\0')
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break;
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}
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name = alloca (name_len);
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status = target_read_memory (name_addr, name, name_len);
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if (status != 0)
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goto err;
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name = obsavestring (name, name_len - 1,
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&symfile_objfile->symbol_obstack);
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status = target_read_memory (addr + 8, buf, 4);
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if (status != 0)
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goto err;
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text_addr = extract_unsigned_integer (buf, 4);
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new_so = (struct so_list *) malloc (sizeof (struct so_list));
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memset ((char *)new_so, 0, sizeof (struct so_list));
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if (so_list_head == NULL)
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{
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so_list_head = new_so;
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so_list_tail = new_so;
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}
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else
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{
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so_list_tail->next = new_so;
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so_list_tail = new_so;
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}
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/* Fill in all the entries in GDB's shared library list. */
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new_so->som_solib.name = name;
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status = target_read_memory (addr + 4, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.struct_version = extract_unsigned_integer (buf + 3, 1);
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new_so->som_solib.bind_mode = extract_unsigned_integer (buf + 2, 1);
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new_so->som_solib.library_version = extract_unsigned_integer (buf, 2);
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new_so->som_solib.text_addr = text_addr;
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status = target_read_memory (addr + 12, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.text_link_addr = extract_unsigned_integer (buf, 4);
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status = target_read_memory (addr + 16, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.text_end = extract_unsigned_integer (buf, 4);
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status = target_read_memory (addr + 20, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.data_start = extract_unsigned_integer (buf, 4);
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status = target_read_memory (addr + 24, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.bss_start = extract_unsigned_integer (buf, 4);
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status = target_read_memory (addr + 28, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.data_end = extract_unsigned_integer (buf, 4);
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status = target_read_memory (addr + 32, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.got_value = extract_unsigned_integer (buf, 4);
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status = target_read_memory (addr + 36, buf, 4);
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if (status != 0)
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goto err;
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new_so->som_solib.next = (void *)extract_unsigned_integer (buf, 4);
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addr = (CORE_ADDR)new_so->som_solib.next;
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new_so->objfile = symbol_file_add (name, from_tty, text_addr, 0, 0, 0);
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new_so->abfd = bfd_openr (name, gnutarget);
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new_so->abfd->cacheable = true;
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if (!bfd_check_format (new_so->abfd, bfd_object))
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{
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error ("\"%s\": not in executable format: %s.",
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name, bfd_errmsg (bfd_get_error ()));
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}
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/* Now we need to build a section table for this library since
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we might be debugging a core file from a dynamically linked
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executable in which the libraries were not privately mapped. */
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if (build_section_table (new_so->abfd,
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&new_so->sections,
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&new_so->sections_end))
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{
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error ("Unable to build section table for shared library\n.");
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return;
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}
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/* Relocate all the sections based on where they got loaded. */
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for (p = new_so->sections; p < new_so->sections_end; p++)
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{
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if (p->the_bfd_section->flags & SEC_CODE)
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{
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p->addr += text_addr - new_so->som_solib.text_link_addr;
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p->endaddr += text_addr - new_so->som_solib.text_link_addr;
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}
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else if (p->the_bfd_section->flags & SEC_DATA)
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{
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p->addr += new_so->som_solib.data_start;
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p->endaddr += new_so->som_solib.data_start;
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}
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}
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/* Now see if we need to map in the text and data for this shared
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library (for example debugging a core file which does not use
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private shared libraries.).
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Carefully peek at the first text address in the library. If the
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read succeeds, then the libraries were privately mapped and were
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included in the core dump file.
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If the peek failed, then the libraries were not privately mapped
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and are not in the core file, we'll have to read them in ourselves. */
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status = target_read_memory (text_addr, buf, 4);
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if (status != 0)
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{
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int old;
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/* Add sections from the shared library to the core target. */
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if (target->to_sections)
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{
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old = target->to_sections_end - target->to_sections;
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target->to_sections = (struct section_table *)
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xrealloc ((char *)target->to_sections,
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((sizeof (struct section_table))
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* (old + bfd_count_sections (new_so->abfd))));
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}
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else
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{
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old = 0;
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target->to_sections = (struct section_table *)
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xmalloc ((sizeof (struct section_table))
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* bfd_count_sections (new_so->abfd));
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}
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target->to_sections_end = (target->to_sections
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+ old + bfd_count_sections (new_so->abfd));
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memcpy ((char *)(target->to_sections + old),
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new_so->sections,
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((sizeof (struct section_table))
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* bfd_count_sections (new_so->abfd)));
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}
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}
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/* Getting new symbols may change our opinion about what is
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frameless. */
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reinit_frame_cache ();
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return;
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old_dld:
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error ("Debugging dynamic executables loaded via the hpux8 dld.sl is not supported.\n");
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return;
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err:
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error ("Error while reading dynamic library list.\n");
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return;
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}
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/* This hook gets called just before the first instruction in the
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inferior process is executed.
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This is our opportunity to set magic flags in the inferior so
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that GDB can be notified when a shared library is mapped in and
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to tell the dynamic linker that a private copy of the library is
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needed (so GDB can set breakpoints in the library).
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__dld_flags is the location of the magic flags; as of this implementation
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there are 3 flags of interest:
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bit 0 when set indicates that private copies of the libraries are needed
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bit 1 when set indicates that the callback hook routine is valid
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bit 2 when set indicates that the dynamic linker should maintain the
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__dld_list structure when loading/unloading libraries.
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Note that shared libraries are not mapped in at this time, so we have
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run the inferior until the libraries are mapped in. Typically this
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means running until the "_start" is called. */
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void
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som_solib_create_inferior_hook()
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{
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struct minimal_symbol *msymbol;
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unsigned int dld_flags, status;
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asection *shlib_info;
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char shadow_contents[BREAKPOINT_MAX], buf[4];
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CORE_ADDR anaddr;
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if (symfile_objfile == NULL)
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return;
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/* First see if the objfile was dynamically linked. */
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shlib_info = bfd_get_section_by_name (symfile_objfile->obfd, "$SHLIB_INFO$");
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if (!shlib_info)
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return;
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/* It's got a $SHLIB_INFO$ section, make sure it's not empty. */
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if (bfd_section_size (symfile_objfile->obfd, shlib_info) == 0)
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return;
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/* Get the address of __dld_flags, if no such symbol exists, then we can
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not debug the shared code. */
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msymbol = lookup_minimal_symbol ("__dld_flags", (struct objfile *) NULL);
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if (msymbol == NULL)
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{
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error ("Unable to find __dld_flags symbol in object file.\n");
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return;
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}
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anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
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/* Read the current contents. */
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status = target_read_memory (anaddr, buf, 4);
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if (status != 0)
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{
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error ("Unable to read __dld_flags\n");
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return;
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}
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dld_flags = extract_unsigned_integer (buf, 4);
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/* Turn on the flags we care about. */
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dld_flags |= 0x5;
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store_unsigned_integer (buf, 4, dld_flags);
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status = target_write_memory (anaddr, buf, 4);
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if (status != 0)
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{
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error ("Unable to write __dld_flags\n");
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return;
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}
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/* Now find the address of _start and set a breakpoint there. */
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msymbol = lookup_minimal_symbol ("_start", symfile_objfile);
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if (msymbol == NULL)
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{
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error ("Unable to find _start symbol in object file.\n");
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return;
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}
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anaddr = SYMBOL_VALUE_ADDRESS (msymbol);
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if (target_insert_breakpoint (anaddr, shadow_contents))
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{
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error ("Unable to set breakpoint at _start.\n");
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return;
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}
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/* Wipe out all knowledge of old shared libraries since their
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mapping can change from one exec to another! */
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while (so_list_head)
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{
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struct so_list *temp;
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free_objfile (so_list_head->objfile);
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temp = so_list_head;
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free (so_list_head);
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so_list_head = temp->next;
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}
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/* Start the process again and wait for it to hit our breakpoint. */
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clear_proceed_status ();
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stop_soon_quietly = 1;
|
|
stop_signal = TARGET_SIGNAL_0;
|
|
do
|
|
{
|
|
target_resume (-1, 0, stop_signal);
|
|
wait_for_inferior ();
|
|
}
|
|
while (stop_signal != TARGET_SIGNAL_TRAP);
|
|
stop_soon_quietly = 0;
|
|
|
|
/* All the libraries should be mapped in now. Remove our breakpoint and
|
|
read in the symbol tables from the shared libraries. */
|
|
if (target_remove_breakpoint (anaddr, shadow_contents))
|
|
{
|
|
error ("Unable to remove breakpoint at _start.\n");
|
|
return;
|
|
}
|
|
|
|
som_solib_add ((char *) 0, 0, (struct target_ops *) 0);
|
|
}
|
|
|
|
/* Return the GOT value for the shared library in which ADDR belongs. If
|
|
ADDR isn't in any known shared library, return zero. */
|
|
|
|
CORE_ADDR
|
|
som_solib_get_got_by_pc (addr)
|
|
CORE_ADDR addr;
|
|
{
|
|
struct so_list *so_list = so_list_head;
|
|
CORE_ADDR got_value = 0;
|
|
|
|
while (so_list)
|
|
{
|
|
if (so_list->som_solib.text_addr <= addr
|
|
&& so_list->som_solib.text_end > addr)
|
|
{
|
|
got_value = so_list->som_solib.got_value;
|
|
break;
|
|
}
|
|
so_list = so_list->next;
|
|
}
|
|
return got_value;
|
|
}
|
|
|
|
/* Dump information about all the currently loaded shared libraries. */
|
|
|
|
static void
|
|
som_sharedlibrary_info_command (ignore, from_tty)
|
|
char *ignore;
|
|
int from_tty;
|
|
{
|
|
struct so_list *so_list = so_list_head;
|
|
|
|
if (exec_bfd == NULL)
|
|
{
|
|
printf_unfiltered ("no exec file.\n");
|
|
return;
|
|
}
|
|
|
|
if (so_list == NULL)
|
|
{
|
|
printf_unfiltered ("No shared libraries loaded at this time.\n");
|
|
return;
|
|
}
|
|
|
|
printf_unfiltered ("Shared Object Libraries\n");
|
|
printf_unfiltered (" %-12s%-12s%-12s%-12s%-12s%-12s\n",
|
|
" flags", " tstart", " tend", " dstart", " dend", " dlt");
|
|
while (so_list)
|
|
{
|
|
unsigned int flags;
|
|
|
|
flags = so_list->som_solib.struct_version << 24;
|
|
flags |= so_list->som_solib.bind_mode << 16;
|
|
flags |= so_list->som_solib.library_version;
|
|
printf_unfiltered ("%s\n", so_list->som_solib.name);
|
|
printf_unfiltered (" %-12s", local_hex_string_custom (flags, "08l"));
|
|
printf_unfiltered ("%-12s",
|
|
local_hex_string_custom (so_list->som_solib.text_addr, "08l"));
|
|
printf_unfiltered ("%-12s",
|
|
local_hex_string_custom (so_list->som_solib.text_end, "08l"));
|
|
printf_unfiltered ("%-12s",
|
|
local_hex_string_custom (so_list->som_solib.data_start, "08l"));
|
|
printf_unfiltered ("%-12s",
|
|
local_hex_string_custom (so_list->som_solib.data_end, "08l"));
|
|
printf_unfiltered ("%-12s\n",
|
|
local_hex_string_custom (so_list->som_solib.got_value, "08l"));
|
|
so_list = so_list->next;
|
|
}
|
|
}
|
|
|
|
void
|
|
_initialize_som_solib ()
|
|
{
|
|
add_info ("sharedlibrary", som_sharedlibrary_info_command,
|
|
"Status of loaded shared object libraries.");
|
|
}
|