blob: 0f81502e5083e6284c4394036e79111e22807864 [file] [log] [blame]
/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
/*
* MT safe ; except for g_on_error_stack_trace, but who wants thread safety
* then
*/
#include "config.h"
#include "glibconfig.h"
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <sys/types.h>
#include <time.h>
#ifdef G_OS_UNIX
#include "glib-unixprivate.h"
#include <errno.h>
#include <unistd.h>
#include <sys/wait.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif /* HAVE_SYS_SELECT_H */
#endif
#include <string.h>
#ifdef G_OS_WIN32
# define STRICT /* Strict typing, please */
# define _WIN32_WINDOWS 0x0401 /* to get IsDebuggerPresent */
# include <windows.h>
# undef STRICT
#else
# include <fcntl.h>
#endif
#include "gbacktrace.h"
#include "gtypes.h"
#include "gmain.h"
#include "gprintfint.h"
#include "gunicode.h"
#include "gutils.h"
#ifndef G_OS_WIN32
static void stack_trace (const char * const *args);
#endif
/* Default to using LLDB for backtraces on macOS. */
#ifdef __APPLE__
#define USE_LLDB
#endif
#ifdef USE_LLDB
#define DEBUGGER "lldb"
#else
#define DEBUGGER "gdb"
#endif
/* People want to hit this from their debugger... */
GLIB_AVAILABLE_IN_ALL volatile gboolean glib_on_error_halt;
volatile gboolean glib_on_error_halt = TRUE;
/**
* g_on_error_query:
* @prg_name: the program name, needed by gdb for the "[S]tack trace"
* option. If @prg_name is %NULL, g_get_prgname() is called to get
* the program name (which will work correctly if gdk_init() or
* gtk_init() has been called)
*
* Prompts the user with
* `[E]xit, [H]alt, show [S]tack trace or [P]roceed`.
* This function is intended to be used for debugging use only.
* The following example shows how it can be used together with
* the g_log() functions.
*
* |[<!-- language="C" -->
* #include <glib.h>
*
* static void
* log_handler (const gchar *log_domain,
* GLogLevelFlags log_level,
* const gchar *message,
* gpointer user_data)
* {
* g_log_default_handler (log_domain, log_level, message, user_data);
*
* g_on_error_query (MY_PROGRAM_NAME);
* }
*
* int
* main (int argc, char *argv[])
* {
* g_log_set_handler (MY_LOG_DOMAIN,
* G_LOG_LEVEL_WARNING |
* G_LOG_LEVEL_ERROR |
* G_LOG_LEVEL_CRITICAL,
* log_handler,
* NULL);
* ...
* ]|
*
* If "[E]xit" is selected, the application terminates with a call
* to _exit(0).
*
* If "[S]tack" trace is selected, g_on_error_stack_trace() is called.
* This invokes gdb, which attaches to the current process and shows
* a stack trace. The prompt is then shown again.
*
* If "[P]roceed" is selected, the function returns.
*
* This function may cause different actions on non-UNIX platforms.
*
* On Windows consider using the `G_DEBUGGER` environment
* variable (see [Running GLib Applications](glib-running.html)) and
* calling g_on_error_stack_trace() instead.
*/
void
g_on_error_query (const gchar *prg_name)
{
#ifndef G_OS_WIN32
static const gchar * const query1 = "[E]xit, [H]alt";
static const gchar * const query2 = ", show [S]tack trace";
static const gchar * const query3 = " or [P]roceed";
gchar buf[16];
if (!prg_name)
prg_name = g_get_prgname ();
retry:
if (prg_name)
_g_fprintf (stdout,
"%s (pid:%u): %s%s%s: ",
prg_name,
(guint) getpid (),
query1,
query2,
query3);
else
_g_fprintf (stdout,
"(process:%u): %s%s: ",
(guint) getpid (),
query1,
query3);
fflush (stdout);
if (isatty(0) && isatty(1))
{
if (fgets (buf, 8, stdin) == NULL)
_exit (0);
}
else
{
strcpy (buf, "E\n");
}
if ((buf[0] == 'E' || buf[0] == 'e')
&& buf[1] == '\n')
_exit (0);
else if ((buf[0] == 'P' || buf[0] == 'p')
&& buf[1] == '\n')
return;
else if (prg_name
&& (buf[0] == 'S' || buf[0] == 's')
&& buf[1] == '\n')
{
g_on_error_stack_trace (prg_name);
goto retry;
}
else if ((buf[0] == 'H' || buf[0] == 'h')
&& buf[1] == '\n')
{
while (glib_on_error_halt)
;
glib_on_error_halt = TRUE;
return;
}
else
goto retry;
#else
if (!prg_name)
prg_name = g_get_prgname ();
/* MessageBox is allowed on UWP apps only when building against
* the debug CRT, which will set -D_DEBUG */
#if defined(_DEBUG) || !defined(G_WINAPI_ONLY_APP)
{
WCHAR *caption = NULL;
if (prg_name && *prg_name)
{
caption = g_utf8_to_utf16 (prg_name, -1, NULL, NULL, NULL);
}
MessageBoxW (NULL, L"g_on_error_query called, program terminating",
caption,
MB_OK|MB_ICONERROR);
g_free (caption);
}
#else
printf ("g_on_error_query called, program '%s' terminating\n",
(prg_name && *prg_name) ? prg_name : "(null)");
#endif
_exit(0);
#endif
}
/**
* g_on_error_stack_trace:
* @prg_name: the program name, needed by gdb for the "[S]tack trace"
* option
*
* Invokes gdb, which attaches to the current process and shows a
* stack trace. Called by g_on_error_query() when the "[S]tack trace"
* option is selected. You can get the current process's program name
* with g_get_prgname(), assuming that you have called gtk_init() or
* gdk_init().
*
* This function may cause different actions on non-UNIX platforms.
*
* When running on Windows, this function is *not* called by
* g_on_error_query(). If called directly, it will raise an
* exception, which will crash the program. If the `G_DEBUGGER` environment
* variable is set, a debugger will be invoked to attach and
* handle that exception (see [Running GLib Applications](glib-running.html)).
*/
void
g_on_error_stack_trace (const gchar *prg_name)
{
#if defined(G_OS_UNIX)
pid_t pid;
gchar buf[16];
const gchar *args[5] = { DEBUGGER, NULL, NULL, NULL, NULL };
int status;
if (!prg_name)
return;
_g_sprintf (buf, "%u", (guint) getpid ());
#ifdef USE_LLDB
args[1] = prg_name;
args[2] = "-p";
args[3] = buf;
#else
args[1] = prg_name;
args[2] = buf;
#endif
pid = fork ();
if (pid == 0)
{
stack_trace (args);
_exit (0);
}
else if (pid == (pid_t) -1)
{
perror ("unable to fork " DEBUGGER);
return;
}
/* Wait until the child really terminates. On Mac OS X waitpid ()
* will also return when the child is being stopped due to tracing.
*/
while (1)
{
pid_t retval = waitpid (pid, &status, 0);
if (WIFEXITED (retval) || WIFSIGNALED (retval))
break;
}
#else
if (IsDebuggerPresent ())
G_BREAKPOINT ();
else
g_abort ();
#endif
}
#ifndef G_OS_WIN32
static gboolean stack_trace_done = FALSE;
static void
stack_trace_sigchld (int signum)
{
stack_trace_done = TRUE;
}
#define BUFSIZE 1024
static inline const char *
get_strerror (char *buffer, gsize n)
{
#if defined(STRERROR_R_CHAR_P)
return strerror_r (errno, buffer, n);
#elif defined(HAVE_STRERROR_R)
int ret = strerror_r (errno, buffer, n);
if (ret == 0 || ret == EINVAL)
return buffer;
return NULL;
#else
const char *error_str = strerror (errno);
if (!error_str)
return NULL;
strncpy (buffer, error_str, n);
return buffer;
#endif
}
static gssize
checked_write (int fd, gconstpointer buf, gsize n)
{
gssize written = write (fd, buf, n);
if (written == -1)
{
char msg[BUFSIZE] = {0};
char error_str[BUFSIZE / 2] = {0};
get_strerror (error_str, sizeof (error_str) - 1);
snprintf (msg, sizeof (msg) - 1, "Unable to write to fd %d: %s", fd, error_str);
perror (msg);
_exit (0);
}
return written;
}
static int
checked_dup (int fd)
{
int new_fd = dup (fd);
if (new_fd == -1)
{
char msg[BUFSIZE] = {0};
char error_str[BUFSIZE / 2] = {0};
get_strerror (error_str, sizeof (error_str) - 1);
snprintf (msg, sizeof (msg) - 1, "Unable to duplicate fd %d: %s", fd, error_str);
perror (msg);
_exit (0);
}
return new_fd;
}
static void
stack_trace (const char * const *args)
{
pid_t pid;
int in_fd[2];
int out_fd[2];
fd_set fdset;
fd_set readset;
struct timeval tv;
int sel, idx, state;
#ifdef USE_LLDB
int line_idx;
#endif
char buffer[BUFSIZE];
char c;
stack_trace_done = FALSE;
signal (SIGCHLD, stack_trace_sigchld);
if (!g_unix_open_pipe_internal (in_fd, TRUE, FALSE) ||
!g_unix_open_pipe_internal (out_fd, TRUE, FALSE))
{
perror ("unable to open pipe");
_exit (0);
}
pid = fork ();
if (pid == 0)
{
/* Save stderr for printing failure below */
int old_err = dup (2);
if (old_err != -1)
{
int getfd = fcntl (old_err, F_GETFD);
if (getfd != -1)
(void) fcntl (old_err, F_SETFD, getfd | FD_CLOEXEC);
}
close (0);
checked_dup (in_fd[0]); /* set the stdin to the in pipe */
close (1);
checked_dup (out_fd[1]); /* set the stdout to the out pipe */
close (2);
checked_dup (out_fd[1]); /* set the stderr to the out pipe */
execvp (args[0], (char **) args); /* exec gdb */
/* Print failure to original stderr */
if (old_err != -1)
{
close (2);
/* We can ignore the return value here as we're failing anyways */
(void) !dup (old_err);
}
perror ("exec " DEBUGGER " failed");
_exit (0);
}
else if (pid == (pid_t) -1)
{
perror ("unable to fork");
_exit (0);
}
FD_ZERO (&fdset);
FD_SET (out_fd[0], &fdset);
#ifdef USE_LLDB
checked_write (in_fd[1], "bt\n", 3);
checked_write (in_fd[1], "p x = 0\n", 8);
checked_write (in_fd[1], "process detach\n", 15);
checked_write (in_fd[1], "quit\n", 5);
#else
/* Don't wrap so that lines are not truncated */
checked_write (in_fd[1], "set width unlimited\n", 20);
checked_write (in_fd[1], "backtrace\n", 10);
checked_write (in_fd[1], "p x = 0\n", 8);
checked_write (in_fd[1], "quit\n", 5);
#endif
idx = 0;
#ifdef USE_LLDB
line_idx = 0;
#endif
state = 0;
while (1)
{
readset = fdset;
tv.tv_sec = 1;
tv.tv_usec = 0;
sel = select (FD_SETSIZE, &readset, NULL, NULL, &tv);
if (sel == -1)
break;
if ((sel > 0) && (FD_ISSET (out_fd[0], &readset)))
{
if (read (out_fd[0], &c, 1))
{
#ifdef USE_LLDB
line_idx += 1;
#endif
switch (state)
{
case 0:
#ifdef USE_LLDB
if (c == '*' || (c == ' ' && line_idx == 1))
#else
if (c == '#')
#endif
{
state = 1;
idx = 0;
buffer[idx++] = c;
}
break;
case 1:
if (idx < BUFSIZE)
buffer[idx++] = c;
if ((c == '\n') || (c == '\r'))
{
buffer[idx] = 0;
_g_fprintf (stdout, "%s", buffer);
state = 0;
idx = 0;
#ifdef USE_LLDB
line_idx = 0;
#endif
}
break;
default:
break;
}
}
}
else if (stack_trace_done)
break;
}
close (in_fd[0]);
close (in_fd[1]);
close (out_fd[0]);
close (out_fd[1]);
_exit (0);
}
#endif /* !G_OS_WIN32 */