binutils-gdb/gdb/cli/cli-logging.c
Marco Barisione 2f822da535 gdb: generate the prefix name for prefix commands on demand
Previously, the prefixname field of struct cmd_list_element was manually
set for prefix commands.  This seems verbose and error prone as it
required every single call to functions adding prefix commands to
specify the prefix name while the same information can be easily
generated.

Historically, this was not possible as the prefix field was null for
many commands, but this was fixed in commit
3f4d92ebdf by Philippe Waroquiers, so
we can rely on the prefix field being set when generating the prefix
name.

This commit also fixes a use after free in this scenario:
* A command gets created via Python (using the gdb.Command class).
  The prefix name member is dynamically allocated.
* An alias to the new command is created. The alias's prefixname is set
  to point to the prefixname for the original command with a direct
  assignment.
* A new command with the same name as the Python command is created.
* The object for the original Python command gets freed and its
  prefixname gets freed as well.
* The alias is updated to point to the new command, but its prefixname
  is not updated so it keeps pointing to the freed one.

gdb/ChangeLog:

	* command.h (add_prefix_cmd): Remove the prefixname argument as
	it can now be generated automatically.  Update all callers.
	(add_basic_prefix_cmd): Ditto.
	(add_show_prefix_cmd): Ditto.
	(add_prefix_cmd_suppress_notification): Ditto.
	(add_abbrev_prefix_cmd): Ditto.
	* cli/cli-decode.c (add_prefix_cmd): Ditto.
	(add_basic_prefix_cmd): Ditto.
	(add_show_prefix_cmd): Ditto.
	(add_prefix_cmd_suppress_notification): Ditto.
	(add_prefix_cmd_suppress_notification): Ditto.
	(add_abbrev_prefix_cmd): Ditto.
	* cli/cli-decode.h (struct cmd_list_element): Replace the
	prefixname member variable with a method which generates the
	prefix name at runtime.  Update all code reading the prefix
	name to use the method, and remove all code setting it.
	* python/py-cmd.c (cmdpy_destroyer): Remove code to free the
	prefixname member as it's now a method.
	(cmdpy_function): Determine if the command is a prefix by
	looking at prefixlist, not prefixname.
2021-05-12 11:19:22 +01:00

218 lines
6.7 KiB
C

/* Command-line output logging for GDB, the GNU debugger.
Copyright (C) 2003-2021 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 3 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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "gdbcmd.h"
#include "ui-out.h"
#include "interps.h"
#include "cli/cli-style.h"
static char *saved_filename;
static char *logging_filename;
static void
show_logging_filename (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("The current logfile is \"%ps\".\n"),
styled_string (file_name_style.style (), value));
}
static bool logging_overwrite;
static void
maybe_warn_already_logging ()
{
if (saved_filename)
warning (_("Currently logging to %s. Turn the logging off and on to "
"make the new setting effective."), saved_filename);
}
static void
set_logging_overwrite (const char *args,
int from_tty, struct cmd_list_element *c)
{
maybe_warn_already_logging ();
}
static void
show_logging_overwrite (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file,
_("Whether logging overwrites or "
"appends to the log file is %s.\n"),
value);
}
/* Value as configured by the user. */
static bool logging_redirect;
static bool debug_redirect;
static void
set_logging_redirect (const char *args,
int from_tty, struct cmd_list_element *c)
{
maybe_warn_already_logging ();
}
static void
show_logging_redirect (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("The logging output mode is %s.\n"), value);
}
/* If we've pushed output files, close them and pop them. */
static void
pop_output_files (void)
{
current_interp_set_logging (NULL, false, false);
/* Stay consistent with handle_redirections. */
if (!current_uiout->is_mi_like_p ())
current_uiout->redirect (NULL);
}
/* This is a helper for the `set logging' command. */
static void
handle_redirections (int from_tty)
{
if (saved_filename != NULL)
{
fprintf_unfiltered (gdb_stdout, "Already logging to %s.\n",
saved_filename);
return;
}
stdio_file_up log (new no_terminal_escape_file ());
if (!log->open (logging_filename, logging_overwrite ? "w" : "a"))
perror_with_name (_("set logging"));
/* Redirects everything to gdb_stdout while this is running. */
if (from_tty)
{
if (!logging_redirect)
fprintf_unfiltered (gdb_stdout, "Copying output to %s.\n",
logging_filename);
else
fprintf_unfiltered (gdb_stdout, "Redirecting output to %s.\n",
logging_filename);
if (!debug_redirect)
fprintf_unfiltered (gdb_stdout, "Copying debug output to %s.\n",
logging_filename);
else
fprintf_unfiltered (gdb_stdout, "Redirecting debug output to %s.\n",
logging_filename);
}
saved_filename = xstrdup (logging_filename);
/* Let the interpreter do anything it needs. */
current_interp_set_logging (std::move (log), logging_redirect,
debug_redirect);
/* Redirect the current ui-out object's output to the log. Use
gdb_stdout, not log, since the interpreter may have created a tee
that wraps the log. Don't do the redirect for MI, it confuses
MI's ui-out scheme. Note that we may get here with MI as current
interpreter, but with the current ui_out as a CLI ui_out, with
'-interpreter-exec console "set logging on"'. */
if (!current_uiout->is_mi_like_p ())
current_uiout->redirect (gdb_stdout);
}
static void
set_logging_on (const char *args, int from_tty)
{
const char *rest = args;
if (rest && *rest)
{
xfree (logging_filename);
logging_filename = xstrdup (rest);
}
handle_redirections (from_tty);
}
static void
set_logging_off (const char *args, int from_tty)
{
if (saved_filename == NULL)
return;
pop_output_files ();
if (from_tty)
fprintf_unfiltered (gdb_stdout, "Done logging to %s.\n", saved_filename);
xfree (saved_filename);
saved_filename = NULL;
}
void _initialize_cli_logging ();
void
_initialize_cli_logging ()
{
static struct cmd_list_element *set_logging_cmdlist, *show_logging_cmdlist;
add_basic_prefix_cmd ("logging", class_support,
_("Set logging options."), &set_logging_cmdlist,
0, &setlist);
add_show_prefix_cmd ("logging", class_support,
_("Show logging options."), &show_logging_cmdlist,
0, &showlist);
add_setshow_boolean_cmd ("overwrite", class_support, &logging_overwrite, _("\
Set whether logging overwrites or appends to the log file."), _("\
Show whether logging overwrites or appends to the log file."), _("\
If set, logging overrides the log file."),
set_logging_overwrite,
show_logging_overwrite,
&set_logging_cmdlist, &show_logging_cmdlist);
add_setshow_boolean_cmd ("redirect", class_support, &logging_redirect, _("\
Set the logging output mode."), _("\
Show the logging output mode."), _("\
If redirect is off, output will go to both the screen and the log file.\n\
If redirect is on, output will go only to the log file."),
set_logging_redirect,
show_logging_redirect,
&set_logging_cmdlist, &show_logging_cmdlist);
add_setshow_boolean_cmd ("debugredirect", class_support,
&debug_redirect, _("\
Set the logging debug output mode."), _("\
Show the logging debug output mode."), _("\
If debug redirect is off, debug will go to both the screen and the log file.\n\
If debug redirect is on, debug will go only to the log file."),
set_logging_redirect,
show_logging_redirect,
&set_logging_cmdlist, &show_logging_cmdlist);
add_setshow_filename_cmd ("file", class_support, &logging_filename, _("\
Set the current logfile."), _("\
Show the current logfile."), _("\
The logfile is used when directing GDB's output."),
NULL,
show_logging_filename,
&set_logging_cmdlist, &show_logging_cmdlist);
add_cmd ("on", class_support, set_logging_on,
_("Enable logging."), &set_logging_cmdlist);
add_cmd ("off", class_support, set_logging_off,
_("Disable logging."), &set_logging_cmdlist);
logging_filename = xstrdup ("gdb.txt");
}