Move the agents directory from a location in Application Support to a temporary directory.

In macOS Catalina, all directories in Application Support are managed by TCC. If TCC thinks that an application is modifying a directory in Application Support which is not its own, it will deny any change to that directory even if filesystem permissions are correct.

By creating a different directory for each agent, and by locating this directories inside $TMPDIR, we avoid triggering TCC's wrath. launchd doesn't care if we launch agents from a temporary directory.

Other improvements introduced as side-effects:
(1) the agents directory is now removed completely as soon as there are no agents running
(2) the agents directory will always be located in the root drive (because all temporary directories are created under /private/var/folders), therefore improving performance if the user's home is remapped to a slower disk

Config.xcconfig

@@ -0,0 +1,28 @@
+// Copyright (c) 2020, OpenEmu Team
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//     * Neither the name of the OpenEmu Team nor the
+//       names of its contributors may be used to endorse or promote products
+//       derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY OpenEmu Team ''AS IS'' AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL OpenEmu Team BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Configuration settings file format documentation can be found at:
+// https://help.apple.com/xcode/#/dev745c5c974
+
+OE_API_VERSION=2

OpenEmuXPCCommunicator.xcodeproj/project.pbxproj

@@ -107,6 +107,8 @@
 
 /* Begin PBXFileReference section */
 		0544B67E23D1347600F63D61 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.xib; name = Base; path = Base.lproj/MainMenu.xib; sourceTree = "<group>"; };
+		05E6959E24CC77EA00ACFB35 /* OpenEmuXPCCommunicatorAgent-Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "OpenEmuXPCCommunicatorAgent-Info.plist"; sourceTree = "<group>"; };
+		05E695A224CC86F100ACFB35 /* Config.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Config.xcconfig; sourceTree = "<group>"; };
 		05F6380722DFFB3700FC49FF /* OEXPCDebugSupport.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = OEXPCDebugSupport.h; sourceTree = "<group>"; };
 		05F6380822DFFB3700FC49FF /* OEXPCDebugSupport.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = OEXPCDebugSupport.m; sourceTree = "<group>"; };
 		C643AC5117935A9A00456656 /* OpenEmuXPCCommunicator.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = OpenEmuXPCCommunicator.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -115,7 +117,7 @@
 		C643AC5817935A9B00456656 /* CoreData.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreData.framework; path = System/Library/Frameworks/CoreData.framework; sourceTree = SDKROOT; };
 		C643AC5917935A9B00456656 /* Foundation.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Foundation.framework; path = System/Library/Frameworks/Foundation.framework; sourceTree = SDKROOT; };
 		C643AC5C17935A9B00456656 /* OpenEmuXPCCommunicator-Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "OpenEmuXPCCommunicator-Info.plist"; sourceTree = "<group>"; };
-		C643AC5E17935A9B00456656 /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
+		C643AC5E17935A9B00456656 /* en */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
 		C643AC6017935A9B00456656 /* OpenEmuXPCCommunicator-Prefix.pch */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "OpenEmuXPCCommunicator-Prefix.pch"; sourceTree = "<group>"; };
 		C643AC6D17935C1200456656 /* OpenEmuXPCCommunicatorAgent */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = OpenEmuXPCCommunicatorAgent; sourceTree = BUILT_PRODUCTS_DIR; };
 		C643AC6E17935C1200456656 /* Foundation.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Foundation.framework; path = System/Library/Frameworks/Foundation.framework; sourceTree = SDKROOT; };
@@ -132,7 +134,7 @@
 		C643AC8D1793916E00456656 /* OpenEmuXPCCommunicator.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OpenEmuXPCCommunicator.h; sourceTree = "<group>"; };
 		C643AC93179392C000456656 /* OEXPCCTestApplication.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = OEXPCCTestApplication.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		C643AC97179392C000456656 /* OEXPCCTestApplication-Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "OEXPCCTestApplication-Info.plist"; sourceTree = "<group>"; };
-		C643AC99179392C000456656 /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
+		C643AC99179392C000456656 /* en */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
 		C643AC9B179392C000456656 /* main.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = main.m; sourceTree = "<group>"; };
 		C643AC9D179392C000456656 /* OEXPCCTestApplication-Prefix.pch */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "OEXPCCTestApplication-Prefix.pch"; sourceTree = "<group>"; };
 		C643AC9F179392C000456656 /* en */ = {isa = PBXFileReference; lastKnownFileType = text.rtf; name = en; path = en.lproj/Credits.rtf; sourceTree = "<group>"; };
@@ -190,6 +192,7 @@
 		C643AC4717935A9A00456656 = {
 			isa = PBXGroup;
 			children = (
+				05E695A224CC86F100ACFB35 /* Config.xcconfig */,
 				C643AC5A17935A9B00456656 /* OpenEmuXPCCommunicator */,
 				C643AC7017935C1200456656 /* OpenEmuXPCCommunicatorAgent */,
 				C643AC95179392C000456656 /* OEXPCCTestApplication */,
@@ -197,7 +200,9 @@
 				C643AC5317935A9A00456656 /* Frameworks */,
 				C643AC5217935A9A00456656 /* Products */,
 			);
+			indentWidth = 4;
 			sourceTree = "<group>";
+			tabWidth = 4;
 			usesTabs = 0;
 		};
 		C643AC5217935A9A00456656 /* Products */ = {
@@ -273,6 +278,7 @@
 			isa = PBXGroup;
 			children = (
 				C643AC7417935C1200456656 /* OpenEmuXPCCommunicatorAgent-Prefix.pch */,
+				05E6959E24CC77EA00ACFB35 /* OpenEmuXPCCommunicatorAgent-Info.plist */,
 			);
 			name = "Supporting Files";
 			sourceTree = "<group>";
@@ -577,6 +583,7 @@
 /* Begin XCBuildConfiguration section */
 		C643AC6417935A9B00456656 /* Debug */ = {
 			isa = XCBuildConfiguration;
+			baseConfigurationReference = 05E695A224CC86F100ACFB35 /* Config.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
@@ -601,6 +608,7 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
+				CURRENT_PROJECT_VERSION = 2;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu99;
@@ -620,6 +628,7 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				MACOSX_DEPLOYMENT_TARGET = 10.14.4;
+				MARKETING_VERSION = 2.0;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = macosx;
 			};
@@ -627,6 +636,7 @@
 		};
 		C643AC6517935A9B00456656 /* Release */ = {
 			isa = XCBuildConfiguration;
+			baseConfigurationReference = 05E695A224CC86F100ACFB35 /* Config.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
@@ -651,6 +661,7 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = YES;
+				CURRENT_PROJECT_VERSION = 2;
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu99;
@@ -663,6 +674,7 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				MACOSX_DEPLOYMENT_TARGET = 10.14.4;
+				MARKETING_VERSION = 2.0;
 				SDKROOT = macosx;
 			};
 			name = Release;
@@ -714,8 +726,11 @@
 			buildSettings = {
 				CODE_SIGN_IDENTITY = "";
 				CODE_SIGN_STYLE = Manual;
+				CREATE_INFOPLIST_SECTION_IN_BINARY = YES;
 				GCC_PRECOMPILE_PREFIX_HEADER = YES;
 				GCC_PREFIX_HEADER = "OpenEmuXPCCommunicatorAgent/OpenEmuXPCCommunicatorAgent-Prefix.pch";
+				INFOPLIST_FILE = "$(SRCROOT)/OpenEmuXPCCommunicatorAgent/OpenEmuXPCCommunicatorAgent-Info.plist";
+				PRODUCT_BUNDLE_IDENTIFIER = "org.openemu.${PRODUCT_NAME:rfc1034identifier}";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 			};
@@ -726,8 +741,11 @@
 			buildSettings = {
 				CODE_SIGN_IDENTITY = "";
 				CODE_SIGN_STYLE = Manual;
+				CREATE_INFOPLIST_SECTION_IN_BINARY = YES;
 				GCC_PRECOMPILE_PREFIX_HEADER = YES;
 				GCC_PREFIX_HEADER = "OpenEmuXPCCommunicatorAgent/OpenEmuXPCCommunicatorAgent-Prefix.pch";
+				INFOPLIST_FILE = "$(SRCROOT)/OpenEmuXPCCommunicatorAgent/OpenEmuXPCCommunicatorAgent-Info.plist";
+				PRODUCT_BUNDLE_IDENTIFIER = "org.openemu.${PRODUCT_NAME:rfc1034identifier}";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 			};

OpenEmuXPCCommunicator/OEXPCCAgentConfiguration.h

@@ -33,9 +33,9 @@
 + (OEXPCCAgentConfiguration *)defaultConfiguration;
 - (void)tearDownAgent;
 
-// Directory containing the agent binaries (Application Support).
-// If for any reason -tearDownAgent hasn't been called on app termination, you may use this method
-// to cleanup the folder.
+/** Temporary directory containing the agent binaries.
+ *  Randomly generated and created as soon as an agent is initialized, and
+ *  deleted as soon as all agents in the current process are torn down. */
 + (NSString *)agentsDirectory;
 
 @property(readonly) NSString *serviceName;

OpenEmuXPCCommunicator/OEXPCCAgentConfiguration.m

@@ -31,6 +31,12 @@ NSString *const _OEXPCCAgentServiceNameArgumentPrefix = @"--org.openemu.OEXPCCAg
 NSString *const _OEXPCCAgentProcessIdentifierArgumentPrefix = @"--org.openemu.OEXPCCAgent.ProcessIdentifier=";
 NSString *const _OEXPCCAgentServiceNamePrefix = @"org.openemu.OEXPCCAgent.";
 
+/* Number of agents currently set up
+ * Used to delete the agents directory when the number of agents reaches zero*/
+static NSInteger liveAgents = 0;
+/* Directory where the agent launchd plists and binaries are located */
+static NSString *agentsDirectory = nil;
+
 @implementation OEXPCCAgentConfiguration
 {
     NSString *_serviceNameArgument;
@@ -65,7 +71,7 @@ NSString *const _OEXPCCAgentServiceNamePrefix = @"org.openemu.OEXPCCAgent.";
         _serviceName = [@[ _OEXPCCAgentServiceNamePrefix, [[NSUUID UUID] UUIDString] ] componentsJoinedByString:@""];
         _serviceNameArgument = [@[ _OEXPCCAgentServiceNameArgumentPrefix, _serviceName ] componentsJoinedByString:@""];
 
-        _agentProcessPath = [[[self class] OEXPCC_agentsApplicationSupportFolderPath] stringByAppendingPathComponent:_serviceName];
+        _agentProcessPath = [[[self class] agentsDirectory] stringByAppendingPathComponent:_serviceName];
         _agentPlistPath = [_agentProcessPath stringByAppendingPathExtension:@"plist"];
 
         [self OEXPCC_setUpAgent];
@@ -75,6 +81,7 @@ NSString *const _OEXPCCAgentServiceNamePrefix = @"org.openemu.OEXPCCAgent.";
 
 - (void)OEXPCC_setUpAgent
 {
+    [[self class] OEXPCC_incrementAgentCount];
     [[self OEXPCC_propertyListForAgent] writeToFile:_agentPlistPath atomically:YES];
     [[NSFileManager defaultManager] copyItemAtPath:[self OEXPCC_originalAgentProgramPath] toPath:_agentProcessPath error:NULL];
 
@@ -103,6 +110,7 @@ NSString *const _OEXPCCAgentServiceNamePrefix = @"org.openemu.OEXPCCAgent.";
 
     [[NSFileManager defaultManager] removeItemAtPath:_agentPlistPath error:NULL];
     [[NSFileManager defaultManager] removeItemAtPath:_agentProcessPath error:NULL];
+    [[self class] OEXPCC_decrementAgentCount];
 }
 
 - (NSString *)agentServiceNameProcessArgument
@@ -135,25 +143,40 @@ NSString *const _OEXPCCAgentServiceNamePrefix = @"org.openemu.OEXPCCAgent.";
     };
 }
 
-+ (NSString *)OEXPCC_agentsApplicationSupportFolderPath
-{
-    static NSString *agentsApplicationSupportFolderPath = nil;
-    static dispatch_once_t onceToken;
-    dispatch_once(&onceToken, ^{
-        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES);
-        if([paths count] == 0) @throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"Could not find Application Support directory." userInfo:nil];
-
-        agentsApplicationSupportFolderPath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"org.openemu.OEXPCCAgent.Agents"];
-
-        [[NSFileManager defaultManager] createDirectoryAtPath:agentsApplicationSupportFolderPath withIntermediateDirectories:YES attributes:nil error:NULL];
-    });
-
-    return agentsApplicationSupportFolderPath;
-}
-
 + (NSString *)agentsDirectory
 {
-    return [self OEXPCC_agentsApplicationSupportFolderPath];
+    @synchronized ([self class]) {
+        if (agentsDirectory)
+            return agentsDirectory;
+        
+        char *tempDirectoryTemplate = NULL;
+        asprintf(&tempDirectoryTemplate, "%s/org.openemu.OEXPCCAgent.Agents.XXXXXXXX", [NSTemporaryDirectory() fileSystemRepresentation]);
+        if (!mkdtemp(tempDirectoryTemplate)) {
+            [NSException exceptionWithName:NSInternalInconsistencyException reason:@"Cannot create temporary agent plist directory." userInfo:nil];
+        }
+        agentsDirectory = [[NSURL fileURLWithFileSystemRepresentation:tempDirectoryTemplate isDirectory:YES relativeToURL:nil] path];
+        return agentsDirectory;
+    }
+}
+
++ (void)OEXPCC_incrementAgentCount
+{
+    @synchronized ([self class]) {
+        liveAgents++;
+        if (liveAgents > 0) {
+            [self agentsDirectory];
+        }
+    }
+}
+
++ (void)OEXPCC_decrementAgentCount
+{
+    @synchronized ([self class]) {
+        liveAgents = MAX(liveAgents - 1, 0);
+        if (liveAgents == 0 && agentsDirectory) {
+            [[NSFileManager defaultManager] removeItemAtPath:agentsDirectory error:nil];
+        }
+    }
 }
 
 @end

OpenEmuXPCCommunicator/OpenEmuXPCCommunicator-Info.plist

@@ -9,7 +9,7 @@
 	<key>CFBundleIconFile</key>
 	<string></string>
 	<key>CFBundleIdentifier</key>
-	<string>org.openemu.${PRODUCT_NAME:rfc1034identifier}</string>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
 	<key>CFBundleInfoDictionaryVersion</key>
 	<string>6.0</string>
 	<key>CFBundleName</key>
@@ -17,14 +17,16 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.0</string>
+	<string>$(MARKETING_VERSION)</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>1</string>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>NSHumanReadableCopyright</key>
 	<string>Copyright © 2013 OpenEmu Team. All rights reserved.</string>
 	<key>NSPrincipalClass</key>
 	<string></string>
+	<key>OEAPIVersion</key>
+	<string>$(OE_API_VERSION)</string>
 </dict>
 </plist>

OpenEmuXPCCommunicatorAgent/OpenEmuXPCCommunicatorAgent-Info.plist

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(MARKETING_VERSION)</string>
+	<key>CFBundleVersion</key>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copyright © 2020 OpenEmu. All rights reserved.</string>
+	<key>OEAPIVersion</key>
+	<string>$(OE_API_VERSION)</string>
+</dict>
+</plist>