Restart on crash

src/systray/systraybar.c

@@ -28,6 +28,7 @@
 #include <X11/extensions/Xdamage.h>
 #include <X11/extensions/Xcomposite.h>
 #include <X11/extensions/Xrender.h>
+#include <unistd.h>
 
 #include "systraybar.h"
 #include "server.h"

src/tint.c

@@ -34,6 +34,8 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <pwd.h>
+#include <time.h>
+#include <sys/time.h>
 
 #ifdef HAVE_SN
 #include <libsn/sn.h>
@@ -75,6 +77,7 @@ XSettingsClient *xsettings_client = NULL;
 
 timeout *detect_compositor_timer = NULL;
 int detect_compositor_timer_counter = 0;
+double start_time = 0;
 
 void detect_compositor(void *arg)
 {
@@ -185,14 +188,9 @@ const char *get_home_dir()
 	return pw->pw_dir;
 }
 
-void crash_handler(int sig)
+void dump_backtrace(int log_fd)
 {
-	char path[4096];
-	sprintf(path, "%s/.tint2-crash.log", get_home_dir());
-	int log_fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0600);
-	log_string(log_fd, "Crashing with signal ");
-	log_string(log_fd, signal_name(sig));
-	log_string(log_fd, "\nBacktrace:\n");
+	log_string(log_fd, YELLOW "\nBacktrace:\n");
 
 #ifdef ENABLE_LIBUNWIND
 	unw_cursor_t cursor;
@@ -225,7 +223,61 @@ void crash_handler(int sig)
 	log_string(log_fd, "Backtrace not supported on this system. Install libunwind or libexecinfo.\n");
 #endif
 #endif
-	_exit(sig);
+	log_string(log_fd, RESET);
+}
+
+// sleep() returns early when signals arrive. This function does not.
+void safe_sleep(int seconds)
+{
+	double t0 = get_time();
+	while (1) {
+		double t = get_time();
+		if (t > t0 + seconds)
+			return;
+		sleep(1);
+	}
+}
+
+void reexecute_tint2()
+{
+	write_string(2, GREEN "Attempting to restart tint2...\n" RESET);
+	// If tint2 cannot stay stable for 30 seconds, don't restart
+	if (get_time() - start_time < 30) {
+		write_string(2, GREEN "Not restarting tint2 since the uptime is too small.\n" RESET);
+		exit(-1);
+	}
+	safe_sleep(1);
+	close_all_fds();
+	char *path = get_own_path();
+	execlp(path, path, "-c", config_path, NULL);
+	exit(-1);
+}
+
+void crash_handler(int sig)
+{
+	// We are going to crash, so restart the panel
+	char path[4096];
+	sprintf(path, "%s/.tint2-crash.log", get_home_dir());
+	int log_fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0600);
+	log_string(log_fd, RED "tint2 crashed with signal " RESET);
+	log_string(log_fd, signal_name(sig));
+	dump_backtrace(log_fd);
+	log_string(log_fd, RED "Please create a bug report with this log output.\n" RESET);
+	close(log_fd);
+	reexecute_tint2();
+}
+
+void x11_io_error(Display *display)
+{
+	// We are going to crash, so restart the panel
+	char path[4096];
+	sprintf(path, "%s/.tint2-crash.log", get_home_dir());
+	int log_fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0600);
+	log_string(log_fd, RED "tint2 crashed due to an X11 I/O error" RESET);
+	dump_backtrace(log_fd);
+	log_string(log_fd, RED "Please create a bug report with this log output.\n" RESET);
+	close(log_fd);
+	reexecute_tint2();
 }
 
 void init(int argc, char *argv[])
@@ -373,6 +425,7 @@ void init_X11_pre_config()
 		exit(1);
 	}
 	XSetErrorHandler((XErrorHandler)server_catch_error);
+	XSetIOErrorHandler((XIOErrorHandler)x11_io_error);
 	server_init_atoms();
 	server.screen = DefaultScreen(server.display);
 	server.root_win = RootWindow(server.display, server.screen);
@@ -1387,6 +1440,8 @@ void dnd_drop(XClientMessageEvent *e)
 int main(int argc, char *argv[])
 {
 start:
+	start_time = get_time();
+
 	init(argc, argv);
 
 	init_X11_pre_config();

src/util/common.c

@@ -32,6 +32,13 @@
 #include "common.h"
 #include "../server.h"
 #include <sys/wait.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <errno.h>
+#include <sys/sysctl.h>
 
 #ifdef HAVE_RSVG
 #include <librsvg/rsvg.h>
@@ -620,3 +627,112 @@ GList *g_list_copy_deep(GList *list, GCopyFunc func, gpointer user_data)
 	return list;
 }
 #endif
+
+// Based loosely on close_allv from
+// https://git.gnome.org/browse/glib/tree/gio/libasyncns/asyncns.c?h=2.21.0#n205
+// license: LGPL version 2.1
+// but with all the junk removed
+// and
+// https://opensource.apple.com/source/sudo/sudo-46/src/closefrom.c
+// license: BSD
+void close_all_fds()
+{
+	const int from_fd = 3;
+
+#ifdef __linux__
+	DIR *d = opendir("/proc/self/fd");
+	if (d) {
+		for (struct dirent *de = readdir(d); de; de = readdir(d)) {
+			if (de->d_name[0] == '.')
+				continue;
+			int fd = atoi(de->d_name);
+			if (fd < from_fd)
+				continue;
+			if (fd == dirfd(d))
+				continue;
+			close(fd);
+		}
+		closedir(d);
+		return;
+	}
+#endif
+
+#if defined(__FreeBSD__) || defined(__DragonFly__) || defined(__OpenBSD__)
+	closefrom(from_fd);
+	return;
+#endif
+
+#if defined(__NetBSD__)
+	fcntl(from_fd, F_CLOSEM, 0);
+#endif
+
+	// Worst case scenario: iterate over all possible fds
+	int max_fd = sysconf(_SC_OPEN_MAX);
+	for (int fd = from_fd; fd < max_fd; fd++) {
+		close(fd);
+	}
+
+	return;
+}
+
+char* get_own_path()
+{
+	const int buf_size = 4096;
+	char *buf = calloc(buf_size, 1);
+
+#ifdef __linux__
+	if (readlink("/proc/self/exe", buf, buf_size) > 0)
+		return buf;
+#endif
+
+#if defined(__FreeBSD__)
+	int mib[4] = {
+		CTL_KERN,
+		KERN_PROC,
+		KERN_PROC_PATHNAME,
+		getpid()
+	};
+
+	size_t max_len = buf_size;
+	if (sysctl(mib, 4, buf, &max_len, NULL, 0) == 0)
+		return buf;
+#endif
+
+#if defined(__DragonFly__)
+	if (readlink("/proc/curproc/file", buf, buf_size) > 0)
+		return buf;
+#endif
+
+#if defined(__NetBSD__)
+	if (readlink("/proc/curproc/exe", buf, buf_size) > 0)
+		return buf;
+#endif
+
+#if defined(__OpenBSD__)
+	int mib[4] = {
+		CTL_KERN,
+		KERN_PROC_ARGS,
+		getpid(),
+		KERN_PROC_ARGV
+	};
+
+	char *path = NULL;
+	size_t len;
+	if (sysctl(mib, 4, NULL, &len, NULL, 0) == 0 && len > 0) {
+		char **argv = malloc(len);
+		if (argv) {
+			if (sysctl(mib, 4, argv, &len, NULL, 0) == 0) {
+				path = realpath(argv[0], NULL);
+			}
+		}
+		free(argv);
+	}
+	if (path) {
+		free(buf);
+		return path;
+	}
+#endif
+
+	sprintf(buf, "tint2");
+	return buf;
+}

src/util/common.h

@@ -14,7 +14,7 @@
 
 #define GREEN  "\033[1;32m"
 #define YELLOW "\033[1;33m"
-#define RED    "\033[31m"
+#define RED    "\033[1;31m"
 #define BLUE   "\033[1;34m"
 #define RESET  "\033[0m"
 
@@ -108,4 +108,8 @@ GList *g_list_copy_deep(GList *list, GCopyFunc func, gpointer user_data);
 #define g_assert_null(expr) g_assert((expr) == NULL)
 #endif
 
+void close_all_fds();
+
+char* get_own_path();
+
 #endif

src/util/timer.c

@@ -435,11 +435,16 @@ void stop_multi_timeout(timeout *t)
 
 double profiling_get_time_old_time = 0;
 
-double profiling_get_time()
+double get_time()
 {
 	struct timespec cur_time;
 	clock_gettime(CLOCK_MONOTONIC, &cur_time);
-	double t = cur_time.tv_sec + cur_time.tv_nsec * 1.0e-9;
+	return cur_time.tv_sec + cur_time.tv_nsec * 1.0e-9;
+}
+
+double profiling_get_time()
+{
+	double t = get_time();
 	if (profiling_get_time_old_time == 0)
 		profiling_get_time_old_time = t;
 	double delta = t - profiling_get_time_old_time;

src/util/timer.h

@@ -69,4 +69,6 @@ struct timespec add_msec_to_timespec(struct timespec ts, int msec);
 // At the first call returns zero.
 double profiling_get_time();
 
+double get_time();
+
 #endif // TIMER_H