Re: [PATCH] Implement new `info core mappings' command

Sergio Durigan Junior
2011-10-26T21:08:13Z

Sergio Durigan Junior <sergiodj@redhat.com> writes:

> Hello there,

I have a theory that you only see errors in your patch when it's already
on the mailing list.

> diff --git a/gdb/NEWS b/gdb/NEWS
> index 5cdb63e..6f8feaa 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -3,6 +3,9 @@
>
> *** Changes since GDB 7.3.1
>
> +* GDB has a new `info core mappings' command. It displays the memory
> + regions in a corefile, similar to `info pro mappings' command.
^^^
Typo.

> +static void
> +info_core_cmd (char *args, int from_tty)
> +{
> + char **argv = NULL;
> + int mappings_f = 1;
> + int all = 0;
> +
> + if (!core_bfd)
> + error (_("You are not using a corefile at the moment."));
> +
> + if (args)
> + {
> + /* Break up 'args' into an argv array. */
> + argv = gdb_buildargv (args);
> + make_cleanup_freeargv (argv);
> + }
> + while (argv != NULL && *argv != NULL)
> + {
> + if (strncmp (argv[0], "mappings", strlen (argv[0])) == 0)
> + {
> + mappings_f = 1;
> + }
> + else if (strncmp (argv[0], "all", strlen (argv[0])) == 0)
> + {
> + all = 1;
> + }
> + argv++;
> + }
> +
> + if (mappings_f || all)
> + print_core_map ();

Forgot to free `argv'.

Please, consider this new patch.

Thanks,

Sergio.

diff --git a/gdb/NEWS b/gdb/NEWS
index 5cdb63e..d04fbe6 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -3,6 +3,9 @@

*** Changes since GDB 7.3.1

+* GDB has a new `info core mappings' command. It displays the memory
+ regions in a corefile, similar to `info proc mappings' command.
+
* GDB has two new commands: "set remote hardware-watchpoint-length-limit"
and "show remote hardware-watchpoint-length-limit". These allows to
set or show the maximum length limit (in bytes) of a remote
diff --git a/gdb/corefile.c b/gdb/corefile.c
index ce3b755..ab3c6bb 100644
--- a/gdb/corefile.c
+++ b/gdb/corefile.c
@@ -24,17 +24,23 @@
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
+#include <ctype.h>
#include "inferior.h"
#include "symtab.h"
+#include "gdbarch.h"
+#include "arch-utils.h"
#include "command.h"
#include "gdbcmd.h"
#include "bfd.h"
+#include "elf-bfd.h"
+#include "elf/internal.h"
#include "target.h"
#include "gdbcore.h"
#include "dis-asm.h"
#include "gdb_stat.h"
#include "completer.h"
#include "exceptions.h"
+#include "objfiles.h"

/* Local function declarations. */

@@ -83,6 +89,189 @@ core_file_command (char *filename, int from_tty)
}
\f

+/* Helper function for `print_core_map'. It is used to iterate
+ over the corefile's sections and print proper information about
+ memory-mappings.
+
+ BFD is the bfd used to get the sections.
+ SECT is the current section being "visited".
+ OBJ is not used. */
+
+static void
+print_proc_map_iter (bfd *bfd, asection *sect, void *obj)
+{
+ /* We're interested in matching sections' names beginning with
+ `load', because they are the sections containing information
+ about the process' memory regions. */
+ static const char *proc_map_match = "load";
+ int proc_map_match_size = strlen (proc_map_match);
+ /* Flag to indicate whether we have found something. */
+ int found = 0;
+ /* The section's size. */
+ bfd_size_type secsize;
+ /* We have to know the bitness of this architecture. */
+ int bitness;
+ /* We'll use these later. They are basically used for iterating
+ over every objfile in the system so that we can find needed
+ information about the memory region being examinated. */
+ struct obj_section *s = NULL;
+ struct objfile *objfile = NULL;
+ /* Fields to be printed for the proc map. */
+ unsigned long start = 0, end = 0;
+ unsigned int size = 0;
+ char *filename = NULL;
+
+ if (strncmp (proc_map_match, sect->name, proc_map_match_size) != 0)
+ /* This section is not useful. */
+ return;
+
+ bitness = gdbarch_addr_bit (gdbarch_from_bfd (bfd));
+
+ /* Unfortunately, some sections in the corefile don't have any
+ content inside. This is bad because we need to print, among
+ other things, its final address in the memory (which is
+ impossible to know if we don't have a size). That's why we
+ first need to check if the section's got anything inside it. */
+ secsize = bfd_section_size (bfd, sect);
+
+ if (secsize == 0)
+ {
+ /* Ok, the section is empty. In this case, we must look inside
+ ELF's Program Header, because (at least) there we have
+ information about the section's size. That's what we're doing
+ here. */
+ Elf_Internal_Phdr *p = elf_tdata (bfd)->phdr;
+ if (p != NULL)
+ {
+ int i;
+ unsigned int n = elf_elfheader (bfd)->e_phnum;
+ for (i = 0; i < n; i++, p++)
+ /* For each entry in the Program Header, we have to
+ check if the section's initial address is equal to
+ the entry's virtual address. If it is, then we
+ have just found the section's entry in the Program
+ Header, and can use the entry's information to
+ complete missing data from the section. */
+ if (sect->vma == p->p_vaddr)
+ {
+ found = 1;
+ break;
+ }
+ if (found)
+ secsize = p->p_memsz;
+ }
+ }
+
+ size = secsize;
+ start = sect->vma;
+ end = (unsigned long) (sect->vma + size);
+
+ /* Now begins a new part of the work. We still don't have complete
+ information about the memory region. For example, we still need
+ to know the filename which is represented by the region. Such
+ info can be gathered from the objfile's data structure, and for
+ that we must iterate over all the objsections and check if the
+ objsection's initial address is inside the section we have at hand.
+ If it is, then we can use this specific objsection to obtain the
+ missing data. */
+ found = 0;
+ ALL_OBJSECTIONS (objfile, s)
+ if (obj_section_addr (s) >= start
+ && obj_section_addr (s) <= end)
+ {
+ found = 1;
+ break;
+ }
+
+ if (found)
+ filename = s->objfile->name;
+
+ if (bitness == 32)
+ printf_filtered ("\t%#10lx %#10lx %#10x %7s\n",
+ start,
+ end,
+ (int) size,
+ filename ? filename : "");
+ else
+ printf_filtered (" %#18lx %#18lx %#10x %7s\n",
+ start,
+ end,
+ (int) size,
+ filename ? filename : "");
+}
+
+/* Implements the `info proc map' command when the user has provided
+ a corefile. */
+
+static void
+print_core_map (void)
+{
+ const char *exe;
+ int bitness;
+
+ gdb_assert (core_bfd != NULL);
+
+ bitness = gdbarch_addr_bit (gdbarch_from_bfd (core_bfd));
+
+ /* Getting the executable name. */
+ exe = bfd_core_file_failing_command (core_bfd);
+
+ printf_filtered (_("exe = '%s'\n"), exe);
+ printf_filtered (_("Mapped address spaces:\n\n"));
+ if (bitness == 32)
+ printf_filtered ("\t%10s %10s %10s %7s\n",
+ "Start Addr",
+ " End Addr",
+ " Size", "objfile");
+ else
+ printf_filtered (" %18s %18s %10s %7s\n",
+ "Start Addr",
+ " End Addr",
+ " Size", "objfile");
+
+ bfd_map_over_sections (core_bfd,
+ print_proc_map_iter,
+ NULL);
+}
+
+/* Implement the `info core' command. */
+
+static void
+info_core_cmd (char *args, int from_tty)
+{
+ char **argv = NULL;
+ int mappings_f = 1;
+ int all = 0;
+ struct cleanup *c;
+
+ if (!core_bfd)
+ error (_("You are not using a corefile at the moment."));
+
+ if (args)
+ {
+ /* Break up 'args' into an argv array. */
+ argv = gdb_buildargv (args);
+ c = make_cleanup_freeargv (argv);
+ }
+ while (argv != NULL && *argv != NULL)
+ {
+ if (strncmp (argv[0], "mappings", strlen (argv[0])) == 0)
+ {
+ mappings_f = 1;
+ }
+ else if (strncmp (argv[0], "all", strlen (argv[0])) == 0)
+ {
+ all = 1;
+ }
+ argv++;
+ }
+
+ if (mappings_f || all)
+ print_core_map ();
+
+ do_cleanups (c);
+}
+
/* If there are two or more functions that wish to hook into
exec_file_command, this function will call all of the hook
functions. */
@@ -450,6 +639,11 @@ _initialize_core (void)
{
struct cmd_list_element *c;

+ add_info ("core", info_core_cmd, _("\
+Show information about a corefile.\n\
+Specify any of the following keywords for detailed info:\n\
+ mappings -- list of mapped memory regions."));
+
c = add_cmd ("core-file", class_files, core_file_command, _("\
Use FILE as core dump for examining memory and registers.\n\
No arg means have no core file. This command has been superseded by the\n\
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index b451a6a..92e06f3 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -17655,6 +17655,13 @@ value; etc. For more information, see the @samp{proc} man page
Show all the information about the process described under all of the
above @code{info proc} subcommands.

+@kindex info core
+@cindex core dump file
+@item info core
+@item info core mappings
+@cindex memory address space mappings
+Report the memory address space ranges accessible in the core file.
+
@ignore
@comment These sub-options of 'info proc' were not included when
@comment procfs.c was re-written. Keep their descriptions around
diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
index 5b0cdf1..190281c 100644
--- a/gdb/testsuite/gdb.base/corefile.exp
+++ b/gdb/testsuite/gdb.base/corefile.exp
@@ -171,6 +171,13 @@ gdb_test_multiple "x/8bd buf2" "$test" {
}
}

+# Test the `info core mapping' command.
+set ws "\[ \t\]+"
+set test "test info core mapping"
+gdb_test "info core mapping" \
+ ".*Mapped address spaces:.*${hex}${ws}${hex}${ws}${hex}.*" \
+ $test
+
# test reinit_frame_cache

gdb_load ${binfile}