Use execve to "launch" Interface on macOS

Co-authored-by: dante ruiz <dante@highfidelity.io>

launchers/darwin/CMakeLists.txt

@@ -43,6 +43,8 @@ set(src_files
   src/LaunchInterface.h
   src/CustomUI.h
   src/CustomUI.m
+  src/NSTask+NSTaskExecveAdditions.h
+  src/NSTask+NSTaskExecveAdditions.m
   src/main.mm
   nib/Window.xib
   nib/SplashScreen.xib

launchers/darwin/src/Launcher.m

@@ -7,6 +7,7 @@
 #import "ProcessScreen.h"
 #import "ErrorViewController.h"
 #import "Settings.h"
+#import "NSTask+NSTaskExecveAdditions.h"
 
 @interface Launcher ()
 
@@ -456,8 +457,6 @@ static BOOL const DELETE_ZIP_FILES = TRUE;
     NSWorkspace *workspace = [NSWorkspace sharedWorkspace];
     NSURL *url = [NSURL fileURLWithPath:[workspace fullPathForApplication:[[self getAppPath] stringByAppendingString:@"interface.app/Contents/MacOS/interface"]]];
 
-    NSError *error = nil;
-
     NSString* contentPath = [[self getDownloadPathForContentAndScripts] stringByAppendingString:@"content"];
     NSString* displayName = [ self displayName];
     NSString* scriptsPath = [[self getAppPath] stringByAppendingString:@"interface.app/Contents/Resources/scripts/simplifiedUIBootstrapper.js"];
@@ -484,13 +483,11 @@ static BOOL const DELETE_ZIP_FILES = TRUE;
                             @"--no-updater",
                             @"--no-launcher", nil];
     }
-    [workspace launchApplicationAtURL:url options:NSWorkspaceLaunchNewInstance configuration:[NSDictionary dictionaryWithObject:arguments forKey:NSWorkspaceLaunchConfigurationArguments] error:&error];
 
-    [NSTimer scheduledTimerWithTimeInterval: 3.0
-                                     target: self
-                                   selector: @selector(exitLauncher:)
-                                   userInfo:nil
-                                    repeats: NO];
+    NSTask *task = [[NSTask alloc] init];
+    task.launchPath = [url path];
+    task.arguments = arguments;
+    [task replaceThisProcess];
 }
 
 - (ProcessState) currentProccessState
@@ -500,15 +497,20 @@ static BOOL const DELETE_ZIP_FILES = TRUE;
 
 - (void) callLaunchInterface:(NSTimer*) timer
 {
+    NSWindow* mainWindow = [[[NSApplication sharedApplication] windows] objectAtIndex:0];
+
     ProcessScreen* processScreen = [[ProcessScreen alloc] initWithNibName:@"ProcessScreen" bundle:nil];
-    [[[[NSApplication sharedApplication] windows] objectAtIndex:0] setContentViewController: processScreen];
-    [self launchInterface];
-}
-
-
-- (void) exitLauncher:(NSTimer*) timer
-{
-    [NSApp terminate:self];
+    [mainWindow setContentViewController: processScreen];
+    @try
+    {
+        [self launchInterface];
+    }
+    @catch (NSException *exception)
+    {
+        NSLog(@"Caught exception: Name: %@, Reason: %@", exception.name, exception.reason);
+        ErrorViewController* errorViewController = [[ErrorViewController alloc] initWithNibName:@"ErrorScreen" bundle:nil];
+        [mainWindow setContentViewController: errorViewController];
+    }
 }
 
 @end

launchers/darwin/src/NSTask+NSTaskExecveAdditions.h

@@ -0,0 +1,9 @@
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface NSTask (NSTaskExecveAdditions)
+- (void) replaceThisProcess;
+@end
+
+NS_ASSUME_NONNULL_END

launchers/darwin/src/NSTask+NSTaskExecveAdditions.m

@@ -0,0 +1,73 @@
+#import "NSTask+NSTaskExecveAdditions.h"
+
+#import <libgen.h>
+
+char **
+toCArray(NSArray<NSString *> *array)
+{
+    // Add one to count to accommodate the NULL that terminates the array.
+    char **cArray = (char **) calloc([array count] + 1, sizeof(char *));
+    if (cArray == NULL) {
+        NSException *exception = [NSException
+                                  exceptionWithName:@"MemoryException"
+                                  reason:@"malloc failed"
+                                  userInfo:nil];
+        @throw exception;
+    }
+    char *str;
+    for (int i = 0; i < [array count]; i++) {
+        str = (char *) [array[i] UTF8String];
+        if (str == NULL) {
+            NSException *exception = [NSException
+                                      exceptionWithName:@"NULLStringException"
+                                      reason:@"UTF8String was NULL"
+                                      userInfo:nil];
+            @throw exception;
+        }
+        if (asprintf(&cArray[i], "%s", str) == -1) {
+            for (int j = 0; j < i; j++) {
+                free(cArray[j]);
+            }
+            free(cArray);
+            NSException *exception = [NSException
+                                      exceptionWithName:@"MemoryException"
+                                      reason:@"malloc failed"
+                                      userInfo:nil];
+            @throw exception;
+        }
+    }
+    return cArray;
+}
+
+@implementation NSTask (NSTaskExecveAdditions)
+
+- (void) replaceThisProcess {
+    char **args = toCArray([@[[self launchPath]] arrayByAddingObjectsFromArray:[self arguments]]);
+
+    NSMutableArray *env = [[NSMutableArray alloc] init];
+    NSDictionary* environvment = [[NSProcessInfo processInfo] environment];
+    for (NSString* key in environvment) {
+        NSString* environmentVariable = [[key stringByAppendingString:@"="] stringByAppendingString:environvment[key]];
+        [env addObject:environmentVariable];
+    }
+
+    char** envp = toCArray(env);
+    // `execve` replaces the current process with `path`.
+    // It will only return if it fails to replace the current process.
+    chdir(dirname(args[0]));
+    execve(args[0], (char * const *)args, envp);
+
+    // If we're here `execve` failed. :(
+    for (int i = 0; i < [[self arguments] count]; i++) {
+        free((void *) args[i]);
+    }
+    free((void *) args);
+
+    NSException *exception = [NSException
+                              exceptionWithName:@"ExecveException"
+                              reason:[NSString stringWithFormat:@"couldn't execve: %s", strerror(errno)]
+                              userInfo:nil];
+    @throw exception;
+}
+
+@end