8sa1-binutils-gdb/gdb/cli/cli-logging.c
Pedro Alves 5be5dbf0ce Fix "-gdb-set logging redirect on" crash
This commit fixes a "-gdb-set logging redirect on" crash by not
handling "logging redirect on" on the fly.

Previous discussion here:
 https://sourceware.org/ml/gdb-patches/2017-01/msg00467.html

Code for handling "logging redirect on" on the fly was added here:
 https://sourceware.org/ml/gdb-patches/2010-08/msg00202.html

Meanwhile, MI gained support for logging, but flipping redirect "on"
on the fly was not considered.  The result is that this sequence of
commands crashes GDB:

 -gdb-set logging on
 -gdb-set logging redirect on

 Program received signal SIGSEGV, Segmentation fault.
 0x00000000008dd7bc in gdb_flush (file=0x2a097f0) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/ui-file.c:95
 194       file->to_flush (file);
 (top-gdb) bt
 #0  0x00000000008dd7bc in gdb_flush(ui_file*) (file=0x2a097f0) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/ui-file.c:95
 #1  0x00000000007b5f34 in gdb_wait_for_event(int) (block=0) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/event-loop.c:752
 #2  0x00000000007b52b6 in gdb_do_one_event() () at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/event-loop.c:322
 #3  0x00000000007b5362 in start_event_loop() () at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/event-loop.c:371
 #4  0x000000000082704a in captured_command_loop(void*) (data=0x0) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/main.c:325
 #5  0x00000000007b8d7c in catch_errors(int (*)(void*), void*, char*, return_mask) (func=0x827008 <captured_command_loop(void*)>, func_args=0x0, errstring=0x11dee51 "", mask=RETURN_MASK_ALL) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/exceptions.c:236
 #6  0x000000000082839b in captured_main(void*) (data=0x7fffffffd820) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/main.c:1148
 During symbol reading, cannot get low and high bounds for subprogram DIE at 24065.
 #7  0x00000000008283c4 in gdb_main(captured_main_args*) (args=0x7fffffffd820) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/main.c:1158
 #8  0x0000000000412d4d in main(int, char**) (argc=4, argv=0x7fffffffd928) at /home/pedro/gdb/mygit/cxx-convertion/src/gdb/gdb.c:32

The handling of redirect on the fly is not really a use case we need
to handle, IMO.  Its inconsistent (other "set logging foo" commands
aren't handled on the fly), and complicates the code significantly.
Instead of complicating it further for MI, go back to the original
idea of warning, only:

  https://sourceware.org/ml/gdb-patches/2010-08/msg00083.html

New test included.

gdb/ChangeLog:
2017-02-02  Pedro Alves  <palves@redhat.com>

	* cli/cli-logging.c (maybe_warn_already_logging): New factored out
	from ...
	(set_logging_overwrite): ... here.
	(logging_no_redirect_file): Delete.
	(set_logging_redirect): Don't handle redirection on the fly.
	Instead warn that "logging off" / "logging on" is necessary.
	(pop_output_files): Delete references to logging_no_redirect_file.
	(show_logging_command): Always speak in terms of what will happen
	once logging is reenabled.

gdb/testsuite/ChangeLog:
2017-02-02  Pedro Alves  <palves@redhat.com>

	* gdb.mi/mi-logging.exp: Add "redirect while already logging"
	tests.
2017-02-02 11:39:56 +00:00

281 lines
8.1 KiB
C

/* Command-line output logging for GDB, the GNU debugger.
Copyright (C) 2003-2017 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"
/* These hold the pushed copies of the gdb output files.
If NULL then nothing has yet been pushed. */
struct saved_output_files
{
struct ui_file *out;
struct ui_file *err;
struct ui_file *log;
struct ui_file *targ;
struct ui_file *targerr;
};
static struct saved_output_files saved_output;
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 \"%s\".\n"),
value);
}
static int 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 (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 int logging_redirect;
static void
set_logging_redirect (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)
{
if (current_interp_set_logging (0, NULL, NULL) == 0)
{
/* Only delete one of the files -- they are all set to the same
value. */
delete gdb_stdout;
gdb_stdout = saved_output.out;
gdb_stderr = saved_output.err;
gdb_stdlog = saved_output.log;
gdb_stdtarg = saved_output.targ;
gdb_stdtargerr = saved_output.targerr;
}
saved_output.out = NULL;
saved_output.err = NULL;
saved_output.log = NULL;
saved_output.targ = NULL;
saved_output.targerr = NULL;
/* 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)
{
ui_file_up output;
ui_file_up no_redirect_file;
if (saved_filename != NULL)
{
fprintf_unfiltered (gdb_stdout, "Already logging to %s.\n",
saved_filename);
return;
}
stdio_file_up log (new stdio_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 (!logging_redirect)
{
no_redirect_file = std::move (log);
output.reset (new tee_file (gdb_stdout, 0, no_redirect_file.get (), 0));
if (from_tty)
fprintf_unfiltered (gdb_stdout, "Copying output to %s.\n",
logging_filename);
}
else
{
output = std::move (log);
if (from_tty)
fprintf_unfiltered (gdb_stdout, "Redirecting output to %s.\n",
logging_filename);
}
saved_filename = xstrdup (logging_filename);
saved_output.out = gdb_stdout;
saved_output.err = gdb_stderr;
saved_output.log = gdb_stdlog;
saved_output.targ = gdb_stdtarg;
saved_output.targerr = gdb_stdtargerr;
/* Let the interpreter do anything it needs. */
if (current_interp_set_logging (1, output.get (),
no_redirect_file.get ()) == 0)
{
gdb_stdout = output.get ();
gdb_stdlog = output.get ();
gdb_stderr = output.get ();
gdb_stdtarg = output.get ();
gdb_stdtargerr = output.get ();
}
output.release ();
no_redirect_file.release ();
/* Don't do the redirect for MI, it confuses MI's ui-out scheme. */
if (!current_uiout->is_mi_like_p ())
current_uiout->redirect (gdb_stdout);
}
static void
set_logging_on (char *args, int from_tty)
{
char *rest = args;
if (rest && *rest)
{
xfree (logging_filename);
logging_filename = xstrdup (rest);
}
handle_redirections (from_tty);
}
static void
set_logging_off (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;
}
static void
set_logging_command (char *args, int from_tty)
{
printf_unfiltered (_("\"set logging\" lets you log output to a file.\n"
"Usage: set logging on [FILENAME]\n"
" set logging off\n"
" set logging file FILENAME\n"
" set logging overwrite [on|off]\n"
" set logging redirect [on|off]\n"));
}
static void
show_logging_command (char *args, int from_tty)
{
if (saved_filename)
printf_unfiltered (_("Currently logging to \"%s\".\n"), saved_filename);
if (saved_filename == NULL
|| strcmp (logging_filename, saved_filename) != 0)
printf_unfiltered (_("Future logs will be written to %s.\n"),
logging_filename);
if (logging_overwrite)
printf_unfiltered (_("Logs will overwrite the log file.\n"));
else
printf_unfiltered (_("Logs will be appended to the log file.\n"));
if (logging_redirect)
printf_unfiltered (_("Output will be sent only to the log file.\n"));
else
printf_unfiltered (_("Output will be logged and displayed.\n"));
}
/* Provide a prototype to silence -Wmissing-prototypes. */
extern initialize_file_ftype _initialize_cli_logging;
void
_initialize_cli_logging (void)
{
static struct cmd_list_element *set_logging_cmdlist, *show_logging_cmdlist;
add_prefix_cmd ("logging", class_support, set_logging_command,
_("Set logging options"), &set_logging_cmdlist,
"set logging ", 0, &setlist);
add_prefix_cmd ("logging", class_support, show_logging_command,
_("Show logging options"), &show_logging_cmdlist,
"show logging ", 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_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");
}