[PATCH] add-symbol-file-from-memory command

Roland McGrath
2004-02-12T00:34:26Z

I've cleaned up some nits that Daniel pointed out. This is the current
version of my add-symbol-file-from-memory patch. I've tested it and it
works with today's mainline gdb. Are there any remaining problems people
see with this code? Can it go in?

Thanks,
Roland

2004-02-11 Roland McGrath <roland@redhat.com>

* symfile.c (symbol_file_add_with_addrs_or_offsets): Take ABFD as
a new argument. Call symfile_bfd_open only if passed a null pointer.
(symbol_file_add, reread_separate_symbols): Update callers.
(build_addr_info): New function, helper for ...
(symbol_file_add_from_memory): New function.
(add_symbol_file_from_memory_command): New function using that.
(_initialize_symfile): Register it for add-symbol-file-from-memory.
* symfile.h (symbol_file_add_from_memory): Declare it.

Index: symfile.c
===================================================================
RCS file: /cvs/src/src/gdb/symfile.c,v
retrieving revision 1.121
diff -p -u -r1.121 symfile.c
--- symfile.c 9 Feb 2004 23:50:55 -0000 1.121
+++ symfile.c 11 Feb 2004 21:02:31 -0000
@@ -799,6 +799,10 @@ new_symfile_objfile (struct objfile *obj
NAME is the file name (which will be tilde-expanded and made
absolute herein) (but we don't free or modify NAME itself).

+ If ABFD is not null, it's already open and should be used instead of
+ opening the file by name. This BFD will be closed on error, and
+ is always consumed by this function.
+
FROM_TTY says how verbose to be.

MAINLINE specifies whether this is the main symbol file, or whether
@@ -811,7 +815,7 @@ new_symfile_objfile (struct objfile *obj
Upon success, returns a pointer to the objfile that was added.
Upon failure, jumps back to command level (never returns). */
static struct objfile *
-symbol_file_add_with_addrs_or_offsets (char *name, int from_tty,
+symbol_file_add_with_addrs_or_offsets (char *name, bfd *abfd, int from_tty,
struct section_addr_info *addrs,
struct section_offsets *offsets,
int num_offsets,
@@ -820,14 +824,16 @@ symbol_file_add_with_addrs_or_offsets (c
struct objfile *objfile;
struct partial_symtab *psymtab;
char *debugfile;
- bfd *abfd;
struct section_addr_info *orig_addrs;
struct cleanup *my_cleanups;

/* Open a bfd for the file, and give user a chance to burp if we'd be
interactively wiping out any existing symbols. */

- abfd = symfile_bfd_open (name);
+ if (abfd == NULL)
+ abfd = symfile_bfd_open (name);
+
+ my_cleanups = make_cleanup_bfd_close (abfd);

if ((have_full_symbols () || have_partial_symbols ())
&& mainline
@@ -836,6 +842,7 @@ symbol_file_add_with_addrs_or_offsets (c
error ("Not confirmed.");

objfile = allocate_objfile (abfd, flags);
+ discard_cleanups (my_cleanups);

orig_addrs = alloc_section_addr_info (bfd_count_sections (abfd));
my_cleanups = make_cleanup (xfree, orig_addrs);
@@ -952,7 +959,8 @@ struct objfile *
symbol_file_add (char *name, int from_tty, struct section_addr_info *addrs,
int mainline, int flags)
{
- return symbol_file_add_with_addrs_or_offsets (name, from_tty, addrs, 0, 0,
+ return symbol_file_add_with_addrs_or_offsets (name, NULL, from_tty,
+ addrs, 0, 0,
mainline, flags);
}

@@ -1802,6 +1810,88 @@ add_shared_symbol_files_command (char *a
#endif
}
\f
+/* Read inferior memory at ADDR to find the header of a loaded object file
+ and read its in-core symbols out of inferior memory. TEMPL is a bfd
+ representing the target's format. */
+struct objfile *
+symbol_file_add_from_memory (bfd *templ, CORE_ADDR addr, int from_tty)
+{
+ struct objfile *objf;
+ bfd *nbfd;
+ asection *sec;
+ bfd_vma loadbase;
+ struct section_addr_info *sai;
+ unsigned int i;
+
+ if (bfd_get_flavour (templ) != bfd_target_elf_flavour)
+ error ("add-symbol-file-from-memory not supported for this target");
+
+ nbfd = bfd_elf_bfd_from_remote_memory (templ, addr, &loadbase,
+ target_read_memory);
+ if (nbfd == NULL)
+ {
+ error ("Failed to read a valid object file image from memory.");
+ return NULL;
+ }
+
+ nbfd->filename = xstrdup ("shared object read from target memory");
+
+ if (!bfd_check_format (nbfd, bfd_object))
+ {
+ /* FIXME: should be checking for errors from bfd_close (for one thing,
+ on error it does not free all the storage associated with the
+ bfd). */
+ bfd_close (nbfd);
+ error ("Got object file from memory but can't read symbols: %s.",
+ bfd_errmsg (bfd_get_error ()));
+ return NULL;
+ }
+
+ sai = alloc_section_addr_info (bfd_count_sections (nbfd));
+ make_cleanup (xfree, sai);
+ i = 0;
+ for (sec = nbfd->sections; sec != NULL; sec = sec->next)
+ if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
+ {
+ sai->other[i].addr = bfd_get_section_vma (nbfd, sec) + loadbase;
+ sai->other[i].name = (char *) bfd_get_section_name (nbfd, sec);
+ sai->other[i].sectindex = sec->index;
+ ++i;
+ }
+
+ objf = symbol_file_add_with_addrs_or_offsets ((char *) nbfd->filename, nbfd,
+ from_tty, sai, NULL, 0, 0,
+ OBJF_SHARED);
+
+ /* This might change our ideas about frames already looked at. */
+ reinit_frame_cache ();
+
+ return objf;
+}
+
+static void
+add_symbol_file_from_memory_command (char *args, int from_tty)
+{
+ CORE_ADDR addr;
+ bfd *templ;
+
+ if (args == NULL)
+ error ("add-symbol-file-from-memory requires an expression argument");
+
+ addr = parse_and_eval_address (args);
+
+ /* We need some representative bfd to know the target we are looking at. */
+ if (symfile_objfile != NULL)
+ templ = symfile_objfile->obfd;
+ else
+ templ = exec_bfd;
+ if (templ == NULL)
+ error ("\
+Must use symbol-file or exec-file before add-symbol-file-from-memory.");
+
+ (void) symbol_file_add_from_memory (templ, addr, from_tty);
+}
+\f
/* Re-read symbols if a symbol-file has changed. */
void
reread_symbols (void)
@@ -3561,6 +3651,13 @@ with the text. SECT is a section name t
&cmdlist);
set_cmd_completer (c, filename_completer);

+ c = add_cmd ("add-symbol-file-from-memory", class_files,
+ add_symbol_file_from_memory_command,
+ "\
+Load the symbols out of memory from a dynamically loaded object file.\n\
+Give an expression for the address of the file's shared object file header.",
+ &cmdlist);
+
c = add_cmd ("add-shared-symbol-files", class_files,
add_shared_symbol_files_command,
"Load the symbols from shared objects in the dynamic linker's link map.",
Index: symfile.h
===================================================================
RCS file: /cvs/src/src/gdb/symfile.h,v
retrieving revision 1.26
diff -p -u -r1.26 symfile.h
--- symfile.h 7 Feb 2004 23:13:47 -0000 1.26
+++ symfile.h 11 Feb 2004 21:02:31 -0000
@@ -306,6 +306,12 @@ extern CORE_ADDR symbol_overlayed_addres
/* Load symbols from a file. */
extern void symbol_file_add_main (char *args, int from_tty);

+/* Read inferior memory at ADDR to find the header of a loaded object file
+ and read its in-core symbols out of inferior memory. TEMPL is a bfd
+ representing the target's format. */
+extern struct objfile *symbol_file_add_from_memory (bfd *templ, CORE_ADDR addr,
+ int from_tty);
+
/* Clear GDB symbol tables. */
extern void symbol_file_clear (int from_tty);