Make the session automatically restart

zerocc2014 · May 5, 2019 · 7a45420 · 7a45420
1 parent fd3308f
commit 7a45420
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Showing 6 changed files with 57 additions and 27 deletions.
diff --git a/app/AppDelegate.h b/app/AppDelegate.h
@@ -14,4 +14,4 @@
 
 @end
 
-extern NSString *const ISHExitedNotification;
+extern NSString *const ProcessExitedNotification;
diff --git a/app/AppDelegate.m b/app/AppDelegate.m
@@ -16,12 +16,23 @@
 
 @interface AppDelegate ()
 
+@property int sessionPid;
+
 @property BOOL exiting;
 
 @end
 
-static void ios_handle_exit(int code) {
-    [[NSNotificationCenter defaultCenter] postNotificationName:ISHExitedNotification object:nil];
+static void ios_handle_exit(struct task *task, int code) {
+    // we are interested in init and in children of init
+    // this is called with pids_lock as an implementation side effect, please do not cite as an example of good API design
+    if (task->parent != NULL && task->parent->parent != NULL)
+        return;
+    dispatch_async(dispatch_get_main_queue(), ^{
+        [[NSNotificationCenter defaultCenter] postNotificationName:ProcessExitedNotification
+                                                            object:nil
+                                                          userInfo:@{@"pid": @(task->pid),
+                                                                     @"code": @(code)}];
+    });
 }
 
 // Put the abort message in the thread name so it gets included in the crash dump
@@ -141,24 +152,32 @@ - (int)startThings {
     task_start(current);
 
     if (UserPreferences.shared.bootEnabled) {
-        err = become_new_init_child();
-        if (err < 0)
-            return err;
-        err = create_stdio("/dev/tty7");
-        if (err < 0)
-            return err;
-        char argv[4096];
-        [self convertCommand:UserPreferences.shared.launchCommand toArgs:argv limitSize:sizeof(argv)];
-        const char *envp = "TERM=xterm-256color\0";
-        err = sys_execve(argv, argv, envp);
+        err = [self startSession];
         if (err < 0)
             return err;
-        task_start(current);
     }
 
     return 0;
 }
 
+- (int)startSession {
+    int err = become_new_init_child();
+    if (err < 0)
+        return err;
+    err = create_stdio("/dev/tty7");
+    if (err < 0)
+        return err;
+    char argv[4096];
+    [self convertCommand:UserPreferences.shared.launchCommand toArgs:argv limitSize:sizeof(argv)];
+    const char *envp = "TERM=xterm-256color\0";
+    err = sys_execve(argv, argv, envp);
+    if (err < 0)
+        return err;
+    self.sessionPid = current->pid;
+    task_start(current);
+    return 0;
+}
+
 - (void)convertCommand:(NSArray<NSString *> *)command toArgs:(char *)argv limitSize:(size_t)maxSize {
     char *p = argv;
     for (NSString *cmd in command) {
@@ -178,6 +197,12 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
     [[NSURLSession.sharedSession dataTaskWithURL:[NSURL URLWithString:@"http://captive.apple.com"]] resume];
 
     [UserPreferences.shared addObserver:self forKeyPath:@"shouldDisableDimming" options:NSKeyValueObservingOptionInitial context:nil];
+
+    [NSNotificationCenter.defaultCenter addObserver:self
+                                           selector:@selector(processExited:)
+                                               name:ProcessExitedNotification
+                                             object:nil];
+
     int err = [self startThings];
     if (err < 0) {
         NSString *message = [NSString stringWithFormat:@"could not initialize"];
@@ -194,6 +219,13 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
     UIApplication.sharedApplication.idleTimerDisabled = UserPreferences.shared.shouldDisableDimming;
 }
 
+- (void)processExited:(NSNotification *)notif {
+    int pid = [notif.userInfo[@"pid"] intValue];
+    if (pid == self.sessionPid) {
+        [self startSession];
+    }
+}
+
 - (void)showMessage:(NSString *)message subtitle:(NSString *)subtitle fatal:(BOOL)fatal {
     dispatch_async(dispatch_get_main_queue(), ^{
         UIAlertController *alert = [UIAlertController alertControllerWithTitle:message message:subtitle preferredStyle:UIAlertControllerStyleAlert];
@@ -217,4 +249,4 @@ - (void)applicationDidEnterBackground:(UIApplication *)application {
 
 @end
 
-NSString *const ISHExitedNotification = @"ISHExitedNotification";
+NSString *const ProcessExitedNotification = @"ProcessExitedNotification";
diff --git a/app/TerminalViewController.m b/app/TerminalViewController.m
@@ -55,11 +55,6 @@ - (void)viewDidLoad {
                    name:UIKeyboardWillHideNotification
                  object:nil];
 
-    [center addObserver:self
-               selector:@selector(ishExited:)
-                   name:ISHExitedNotification
-                 object:nil];
-
     [self _updateStyleFromPreferences:NO];
     [[UserPreferences shared] addObserver:self forKeyPath:@"theme" options:NSKeyValueObservingOptionNew context:nil];
 

diff --git a/kernel/exit.c b/kernel/exit.c
@@ -30,6 +30,8 @@ static bool exit_tgroup(struct task *task) {
     return group_dead;
 }
 
+void (*exit_hook)(struct task *task, int code) = NULL;
+
 noreturn void do_exit(int status) {
     // has to happen before mm_release
     addr_t clear_tid = current->clear_tid;
@@ -79,6 +81,9 @@ noreturn void do_exit(int status) {
             notify(&parent->group->child_exit);
             send_signal(parent, leader->exit_signal);
         }
+
+        if (exit_hook != NULL)
+            exit_hook(current, status);
     }
 
     vfork_notify(current);
@@ -111,9 +116,8 @@ noreturn void do_exit_group(int status) {
     do_exit(status);
 }
 
-void (*exit_hook)(int code) = NULL;
 // always called from init process
-static void halt_system(int status) {
+static void halt_system() {
     // brutally murder everything
     // which will leave everything in an inconsistent state. I will solve this problem later.
     for (int i = 2; i < MAX_PID; i++) {
@@ -129,9 +133,6 @@ static void halt_system(int status) {
         mount_remove(mount);
     }
     unlock(&mounts_lock);
-
-    if (exit_hook != NULL)
-        exit_hook(status);
 }
 
 dword_t sys_exit(dword_t status) {

diff --git a/kernel/task.h b/kernel/task.h
@@ -150,7 +150,7 @@ extern void (*task_run_hook)(void);
 // TODO document
 void task_start(struct task *task);
 
-extern void (*exit_hook)(int code);
+extern void (*exit_hook)(struct task *task, int code);
 
 #define superuser() (current != NULL && current->euid == 0)
 

diff --git a/xX_main_Xx.h b/xX_main_Xx.h
@@ -10,7 +10,9 @@
 #define IOPOL_VFS_HFS_CASE_SENSITIVITY_FORCE_CASE_SENSITIVE 1
 #endif
 
-static void exit_handler(int code) {
+static void exit_handler(struct task *task, int code) {
+    if (task->parent != NULL)
+        return;
     if (code & 0xff)
         raise(code & 0xff);
     else
Original file line number	Diff line number	Diff line change
Expand Up		@@ -14,4 +14,4 @@

		@end

		extern NSString *const ISHExitedNotification;
		extern NSString *const ProcessExitedNotification;