macos: support env vars for surface config, clean up surface config

include/ghostty.h

@@ -385,6 +385,11 @@ typedef struct {
   bool rectangle;
 } ghostty_selection_s;
 
+typedef struct {
+  const char* key;
+  const char* value;
+} ghostty_env_var_s;
+
 typedef struct {
   void* nsview;
 } ghostty_platform_macos_s;
@@ -406,6 +411,8 @@ typedef struct {
   float font_size;
   const char* working_directory;
   const char* command;
+  ghostty_env_var_s* env_vars;
+  size_t env_var_count;
 } ghostty_surface_config_s;
 
 typedef struct {
@@ -807,7 +814,8 @@ void ghostty_app_set_color_scheme(ghostty_app_t, ghostty_color_scheme_e);
 
 ghostty_surface_config_s ghostty_surface_config_new();
 
-ghostty_surface_t ghostty_surface_new(ghostty_app_t, ghostty_surface_config_s*);
+ghostty_surface_t ghostty_surface_new(ghostty_app_t,
+                                      const ghostty_surface_config_s*);
 void ghostty_surface_free(ghostty_surface_t);
 void* ghostty_surface_userdata(ghostty_surface_t);
 ghostty_app_t ghostty_surface_app(ghostty_surface_t);

macos/Ghostty.xcodeproj/project.pbxproj

@@ -15,6 +15,7 @@
 		A50297352DFA0F3400B4E924 /* Double+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = A50297342DFA0F3300B4E924 /* Double+Extension.swift */; };
 		A511940F2E050595007258CC /* CloseTerminalIntent.swift in Sources */ = {isa = PBXBuildFile; fileRef = A511940E2E050590007258CC /* CloseTerminalIntent.swift */; };
 		A51194112E05A483007258CC /* QuickTerminalIntent.swift in Sources */ = {isa = PBXBuildFile; fileRef = A51194102E05A480007258CC /* QuickTerminalIntent.swift */; };
+		A51194132E05D006007258CC /* Optional+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = A51194122E05D003007258CC /* Optional+Extension.swift */; };
 		A514C8D62B54A16400493A16 /* Ghostty.Config.swift in Sources */ = {isa = PBXBuildFile; fileRef = A514C8D52B54A16400493A16 /* Ghostty.Config.swift */; };
 		A514C8D72B54A16400493A16 /* Ghostty.Config.swift in Sources */ = {isa = PBXBuildFile; fileRef = A514C8D52B54A16400493A16 /* Ghostty.Config.swift */; };
 		A514C8D82B54DC6800493A16 /* Ghostty.App.swift in Sources */ = {isa = PBXBuildFile; fileRef = A53D0C992B543F3B00305CE6 /* Ghostty.App.swift */; };
@@ -153,6 +154,7 @@
 		A50297342DFA0F3300B4E924 /* Double+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Double+Extension.swift"; sourceTree = "<group>"; };
 		A511940E2E050590007258CC /* CloseTerminalIntent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CloseTerminalIntent.swift; sourceTree = "<group>"; };
 		A51194102E05A480007258CC /* QuickTerminalIntent.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = QuickTerminalIntent.swift; sourceTree = "<group>"; };
+		A51194122E05D003007258CC /* Optional+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Optional+Extension.swift"; sourceTree = "<group>"; };
 		A514C8D52B54A16400493A16 /* Ghostty.Config.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Ghostty.Config.swift; sourceTree = "<group>"; };
 		A51544FD2DFB1110009E85D8 /* TitlebarTabsTahoeTerminalWindow.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TitlebarTabsTahoeTerminalWindow.swift; sourceTree = "<group>"; };
 		A51544FF2DFB112E009E85D8 /* TerminalTabsTitlebarTahoe.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = TerminalTabsTitlebarTahoe.xib; sourceTree = "<group>"; };
@@ -506,6 +508,7 @@
 				A586366E2DF25D8300E04A10 /* Duration+Extension.swift */,
 				A53A29802DB44A5E00B6E02C /* KeyboardShortcut+Extension.swift */,
 				A53A297E2DB4480A00B6E02C /* EventModifiers+Extension.swift */,
+				A51194122E05D003007258CC /* Optional+Extension.swift */,
 				C159E81C2B66A06B00FDFE9C /* OSColor+Extension.swift */,
 				A599CDAF2CF103F20049FA26 /* NSAppearance+Extension.swift */,
 				A5A2A3CB2D444AB80033CF96 /* NSApplication+Extension.swift */,
@@ -786,6 +789,7 @@
 				CFBB5FEA2D231E5000FD62EE /* QuickTerminalSpaceBehavior.swift in Sources */,
 				A54B0CE92D0CECD100CBEFF8 /* ColorizedGhosttyIconView.swift in Sources */,
 				A5D0AF3D2B37804400D21823 /* CodableBridge.swift in Sources */,
+				A51194132E05D006007258CC /* Optional+Extension.swift in Sources */,
 				A5D0AF3B2B36A1DE00D21823 /* TerminalRestorable.swift in Sources */,
 				C1F26EA72B738B9900404083 /* NSView+Extension.swift in Sources */,
 				A586366F2DF25D8600E04A10 /* Duration+Extension.swift in Sources */,

macos/Sources/Ghostty/SurfaceView.swift

@@ -419,17 +419,35 @@ extension Ghostty {
         /// Explicit command to set
         var command: String? = nil
         
+        /// Environment variables to set for the terminal
+        var environmentVariables: [String: String] = [:]
+
         init() {}
 
         init(from config: ghostty_surface_config_s) {
             self.fontSize = config.font_size
-            self.workingDirectory = String.init(cString: config.working_directory, encoding: .utf8)
+            if let workingDirectory = config.working_directory {
-            self.command = String.init(cString: config.command, encoding: .utf8)
+                self.workingDirectory = String.init(cString: workingDirectory, encoding: .utf8)
+            }
+            if let command = config.command {
+                self.command = String.init(cString: command, encoding: .utf8)
+            }
+
+            // Convert the C env vars to Swift dictionary
+            if config.env_var_count > 0, let envVars = config.env_vars {
+                for i in 0..<config.env_var_count {
+                    let envVar = envVars[i]
+                    if let key = String(cString: envVar.key, encoding: .utf8),
+                       let value = String(cString: envVar.value, encoding: .utf8) {
+                        self.environmentVariables[key] = value
+                    }
+                }
+            }
         }
 
-        /// Returns the ghostty configuration for this surface configuration struct. The memory
+        /// Provides a C-compatible ghostty configuration within a closure. The configuration
-        /// in the returned struct is only valid as long as this struct is retained.
+        /// and all its string pointers are only valid within the closure.
-        func ghosttyConfig(view: SurfaceView) -> ghostty_surface_config_s {
+        func withCValue<T>(view: SurfaceView, _ body: (inout ghostty_surface_config_s) throws -> T) rethrows -> T {
             var config = ghostty_surface_config_new()
             config.userdata = Unmanaged.passUnretained(view).toOpaque()
             #if os(macOS)
@@ -438,7 +456,6 @@ extension Ghostty {
                 nsview: Unmanaged.passUnretained(view).toOpaque()
             ))
             config.scale_factor = NSScreen.main!.backingScaleFactor
-
             #elseif os(iOS)
             config.platform_tag = GHOSTTY_PLATFORM_IOS
             config.platform = ghostty_platform_u(ios: ghostty_platform_ios_s(
@@ -453,15 +470,42 @@ extension Ghostty {
             #error("unsupported target")
             #endif
 
-            if let fontSize = fontSize { config.font_size = fontSize }
+            // Zero is our default value that means to inherit the font size.
-            if let workingDirectory = workingDirectory {
+            config.font_size = fontSize ?? 0
-                config.working_directory = (workingDirectory as NSString).utf8String
-            }
-            if let command = command {
-                config.command = (command as NSString).utf8String
-            }
 
-            return config
+            // Use withCString to ensure strings remain valid for the duration of the closure
+            return try workingDirectory.withCString { cWorkingDir in
+                config.working_directory = cWorkingDir
+
+                return try command.withCString { cCommand in
+                    config.command = cCommand
+
+                    // Convert dictionary to arrays for easier processing
+                    let keys = Array(environmentVariables.keys)
+                    let values = Array(environmentVariables.values)
+
+                    // Create C strings for all keys and values
+                    return try keys.withCStrings { keyCStrings in
+                        return try values.withCStrings { valueCStrings in
+                            // Create array of ghostty_env_var_s
+                            var envVars = Array<ghostty_env_var_s>()
+                            envVars.reserveCapacity(environmentVariables.count)
+                            for i in 0..<environmentVariables.count {
+                                envVars.append(ghostty_env_var_s(
+                                    key: keyCStrings[i],
+                                    value: valueCStrings[i]
+                                ))
+                            }
+
+                            return try envVars.withUnsafeMutableBufferPointer { buffer in
+                                config.env_vars = buffer.baseAddress
+                                config.env_var_count = environmentVariables.count
+                                return try body(&config)
+                            }
+                        }
+                    }
+                }
+            }
         }
     }
 

macos/Sources/Ghostty/SurfaceView_AppKit.swift

@@ -290,8 +290,10 @@ extension Ghostty {
 
             // Setup our surface. This will also initialize all the terminal IO.
             let surface_cfg = baseConfig ?? SurfaceConfiguration()
-            var surface_cfg_c = surface_cfg.ghosttyConfig(view: self)
+            let surface = surface_cfg.withCValue(view: self) { surface_cfg_c in
-            guard let surface = ghostty_surface_new(app, &surface_cfg_c) else {
+                ghostty_surface_new(app, &surface_cfg_c)
+            }
+            guard let surface = surface else {
                 self.error = Ghostty.Error.apiFailed
                 return
             }

macos/Sources/Ghostty/SurfaceView_UIKit.swift

@@ -57,8 +57,10 @@ extension Ghostty {
 
             // Setup our surface. This will also initialize all the terminal IO.
             let surface_cfg = baseConfig ?? SurfaceConfiguration()
-            var surface_cfg_c = surface_cfg.ghosttyConfig(view: self)
+            let surface = surface_cfg.withCValue(view: self) { surface_cfg_c in
-            guard let surface = ghostty_surface_new(app, &surface_cfg_c) else {
+                ghostty_surface_new(app, &surface_cfg_c)
+            }
+            guard let surface = surface else {
                 // TODO
                 return
             }

macos/Sources/Helpers/Extensions/Array+Extension.swift

@@ -21,3 +21,28 @@ extension Array {
         return i + 1
     }
 }
+
+extension Array where Element == String {
+    /// Executes a closure with an array of C string pointers.
+    func withCStrings<T>(_ body: ([UnsafePointer<Int8>?]) throws -> T) rethrows -> T {
+        // Handle empty array
+        if isEmpty {
+            return try body([])
+        }
+
+        // Recursive helper to process strings
+        func helper(index: Int, accumulated: [UnsafePointer<Int8>?], body: ([UnsafePointer<Int8>?]) throws -> T) rethrows -> T {
+            if index == count {
+                return try body(accumulated)
+            } else {
+                return try self[index].withCString { cStr in
+                    var newAccumulated = accumulated
+                    newAccumulated.append(cStr)
+                    return try helper(index: index + 1, accumulated: newAccumulated, body: body)
+                }
+            }
+        }
+
+        return try helper(index: 0, accumulated: [], body: body)
+    }
+}

macos/Sources/Helpers/Extensions/Optional+Extension.swift

@@ -0,0 +1,10 @@
+extension Optional where Wrapped == String {
+    /// Executes a closure with a C string pointer, handling nil gracefully.
+    func withCString<T>(_ body: (UnsafePointer<Int8>?) throws -> T) rethrows -> T {
+        if let string = self {
+            return try string.withCString(body)
+        } else {
+            return try body(nil)
+        }
+    }
+}

src/apprt/embedded.zig

@@ -376,6 +376,14 @@ pub const PlatformTag = enum(c_int) {
     ios = 2,
 };
 
+pub const EnvVar = extern struct {
+    /// The name of the environment variable.
+    key: [*:0]const u8,
+
+    /// The value of the environment variable.
+    value: [*:0]const u8,
+};
+
 pub const Surface = struct {
     app: *App,
     platform: Platform,
@@ -407,7 +415,7 @@ pub const Surface = struct {
         font_size: f32 = 0,
 
         /// The working directory to load into.
-        working_directory: [*:0]const u8 = "",
+        working_directory: ?[*:0]const u8 = null,
 
         /// The command to run in the new surface. If this is set then
         /// the "wait-after-command" option is also automatically set to true,
@@ -417,7 +425,11 @@ pub const Surface = struct {
         /// despite Ghostty allowing directly executed commands via config.
         /// This is a legacy thing and we should probably change it in the
         /// future once we have a concrete use case.
-        command: [*:0]const u8 = "",
+        command: ?[*:0]const u8 = null,
+
+        /// Extra environment variables to set for the surface.
+        env_vars: ?[*]EnvVar = null,
+        env_var_count: usize = 0,
     };
 
     pub fn init(self: *Surface, app: *App, opts: Options) !void {
@@ -443,41 +455,59 @@ pub const Surface = struct {
         defer config.deinit();
 
         // If we have a working directory from the options then we set it.
-        const wd = std.mem.sliceTo(opts.working_directory, 0);
+        if (opts.working_directory) |c_wd| {
-        if (wd.len > 0) wd: {
+            const wd = std.mem.sliceTo(c_wd, 0);
-            var dir = std.fs.openDirAbsolute(wd, .{}) catch |err| {
+            if (wd.len > 0) wd: {
-                log.warn(
+                var dir = std.fs.openDirAbsolute(wd, .{}) catch |err| {
-                    "error opening requested working directory dir={s} err={}",
+                    log.warn(
-                    .{ wd, err },
+                        "error opening requested working directory dir={s} err={}",
-                );
+                        .{ wd, err },
-                break :wd;
+                    );
-            };
+                    break :wd;
-            defer dir.close();
+                };
+                defer dir.close();
 
-            const stat = dir.stat() catch |err| {
+                const stat = dir.stat() catch |err| {
-                log.warn(
+                    log.warn(
-                    "failed to stat requested working directory dir={s} err={}",
+                        "failed to stat requested working directory dir={s} err={}",
-                    .{ wd, err },
+                        .{ wd, err },
-                );
+                    );
-                break :wd;
+                    break :wd;
-            };
+                };
 
-            if (stat.kind != .directory) {
+                if (stat.kind != .directory) {
-                log.warn(
+                    log.warn(
-                    "requested working directory is not a directory dir={s}",
+                        "requested working directory is not a directory dir={s}",
-                    .{wd},
+                        .{wd},
-                );
+                    );
-                break :wd;
+                    break :wd;
+                }
+
+                config.@"working-directory" = wd;
             }
-
-            config.@"working-directory" = wd;
         }
 
         // If we have a command from the options then we set it.
-        const cmd = std.mem.sliceTo(opts.command, 0);
+        if (opts.command) |c_command| {
-        if (cmd.len > 0) {
+            const cmd = std.mem.sliceTo(c_command, 0);
-            config.command = .{ .shell = cmd };
+            if (cmd.len > 0) {
-            config.@"wait-after-command" = true;
+                config.command = .{ .shell = cmd };
+                config.@"wait-after-command" = true;
+            }
+        }
+
+        // Apply any environment variables that were requested.
+        if (opts.env_var_count > 0) {
+            const alloc = config.arenaAlloc();
+            for (opts.env_vars.?[0..opts.env_var_count]) |env_var| {
+                const key = std.mem.sliceTo(env_var.key, 0);
+                const value = std.mem.sliceTo(env_var.value, 0);
+                try config.env.map.put(
+                    alloc,
+                    try alloc.dupeZ(u8, key),
+                    try alloc.dupeZ(u8, value),
+                );
+            }
         }
 
         // Initialize our surface right away. We're given a view that is

src/config/Config.zig

@@ -3004,6 +3004,11 @@ pub fn loadRecursiveFiles(self: *Config, alloc_gpa: Allocator) !void {
     }
 }
 
+/// Get the arena allocator associated with the configuration.
+pub fn arenaAlloc(self: *Config) Allocator {
+    return self._arena.?.allocator();
+}
+
 /// Change the state of conditionals and reload the configuration
 /// based on the new state. This returns a new configuration based
 /// on the new state. The caller must free the old configuration if they