Open new log file handle after fork()

This would also need to be done in the
nested fork() calls.

Signed-off-by: AnErrupTion <anerruption@disroot.org>

src/auth.zig

@@ -57,25 +57,31 @@ pub fn authenticate(allocator: std.mem.Allocator, log_writer: *std.Io.Writer, op
     };
     var handle: ?*interop.pam.pam_handle = undefined;
 
+    try log_writer.writeAll("[pam] starting session\n");
     var status = interop.pam.pam_start(options.service_name, null, &conv, &handle);
     if (status != interop.pam.PAM_SUCCESS) return pamDiagnose(status);
     defer _ = interop.pam.pam_end(handle, status);
 
     // Set PAM_TTY as the current TTY. This is required in case it isn't being set by another PAM module
+    try log_writer.writeAll("[pam] setting tty\n");
     status = interop.pam.pam_set_item(handle, interop.pam.PAM_TTY, pam_tty_str.ptr);
     if (status != interop.pam.PAM_SUCCESS) return pamDiagnose(status);
 
     // Do the PAM routine
+    try log_writer.writeAll("[pam] authenticating\n");
     status = interop.pam.pam_authenticate(handle, 0);
     if (status != interop.pam.PAM_SUCCESS) return pamDiagnose(status);
 
+    try log_writer.writeAll("[pam] validating account\n");
     status = interop.pam.pam_acct_mgmt(handle, 0);
     if (status != interop.pam.PAM_SUCCESS) return pamDiagnose(status);
 
+    try log_writer.writeAll("[pam] setting credentials\n");
     status = interop.pam.pam_setcred(handle, interop.pam.PAM_ESTABLISH_CRED);
     if (status != interop.pam.PAM_SUCCESS) return pamDiagnose(status);
     defer status = interop.pam.pam_setcred(handle, interop.pam.PAM_DELETE_CRED);
 
+    try log_writer.writeAll("[pam] opening session\n");
     status = interop.pam.pam_open_session(handle, 0);
     if (status != interop.pam.PAM_SUCCESS) return pamDiagnose(status);
     defer status = interop.pam.pam_close_session(handle, 0);

src/main.zig

@@ -264,29 +264,9 @@ pub fn main() !void {
     var log_file: std.fs.File = undefined;
     defer log_file.close();
 
-    var could_open_log_file = true;
-    open_log_file: {
-        log_file = std.fs.cwd().openFile(config.ly_log, .{ .mode = .write_only }) catch std.fs.cwd().createFile(config.ly_log, .{ .mode = 0o666 }) catch {
-            // If we could neither open an existing log file nor create a new
-            // one, abort.
-            could_open_log_file = false;
-            break :open_log_file;
-        };
-    }
-
-    if (!could_open_log_file) {
-        log_file = try std.fs.openFileAbsolute("/dev/null", .{ .mode = .write_only });
-    }
-
     var log_buffer: [1024]u8 = undefined;
-    var log_file_writer = log_file.writer(&log_buffer);
+    var log_file_writer: std.fs.File.Writer = undefined;
-
+    var could_open_log_file = try openLogFile(config.ly_log, &log_file, &log_buffer, &log_file_writer);
-    // Seek to the end of the log file
-    if (could_open_log_file) {
-        const stat = try log_file.stat();
-        try log_file_writer.seekTo(stat.size);
-    }
-
     var log_writer = &log_file_writer.interface;
 
     // These strings only end up getting freed if the user quits Ly using Ctrl+C, which is fine since in the other cases
@@ -937,6 +917,8 @@ pub fn main() !void {
                 defer shared_err.deinit();
 
                 {
+                    log_file.close();
+
                     session_pid = try std.posix.fork();
                     if (session_pid == 0) {
                         const current_environment = session.label.list.items[session.label.current].environment;
@@ -960,10 +942,18 @@ pub fn main() !void {
                         };
                         std.posix.sigaction(std.posix.SIG.CHLD, &tty_control_transfer_act, null);
 
+                        could_open_log_file = try openLogFile(config.ly_log, &log_file, &log_buffer, &log_file_writer);
+                        log_writer = &log_file_writer.interface;
+                        defer log_file.close();
+
                         auth.authenticate(allocator, log_writer, auth_options, current_environment, login.getCurrentUsername(), password.text.items) catch |err| {
                             shared_err.writeError(err);
+
+                            try log_writer.flush();
                             std.process.exit(1);
                         };
+
+                        try log_writer.flush();
                         std.process.exit(0);
                     }
 
@@ -972,6 +962,9 @@ pub fn main() !void {
                     // This is a workaround to ensure the session process has exited before re-initializing the TTY.
                     std.Thread.sleep(std.time.ns_per_s * 1);
                     session_pid = -1;
+
+                    could_open_log_file = try openLogFile(config.ly_log, &log_file, &log_buffer, &log_file_writer);
+                    log_writer = &log_file_writer.interface;
                 }
 
                 // Take back control of the TTY
@@ -1060,6 +1053,33 @@ pub fn main() !void {
     }
 }
 
+fn openLogFile(path: []const u8, log_file: *std.fs.File, buffer: []u8, writer: *std.fs.File.Writer) !bool {
+    var could_open_log_file = true;
+    open_log_file: {
+        log_file.* = std.fs.cwd().openFile(path, .{ .mode = .write_only }) catch std.fs.cwd().createFile(path, .{ .mode = 0o666 }) catch {
+            // If we could neither open an existing log file nor create a new
+            // one, abort.
+            could_open_log_file = false;
+            break :open_log_file;
+        };
+    }
+
+    if (!could_open_log_file) {
+        log_file.* = try std.fs.openFileAbsolute("/dev/null", .{ .mode = .write_only });
+    }
+
+    var log_file_writer = log_file.writer(buffer);
+
+    // Seek to the end of the log file
+    if (could_open_log_file) {
+        const stat = try log_file.stat();
+        try log_file_writer.seekTo(stat.size);
+    }
+
+    writer.* = log_file_writer;
+    return could_open_log_file;
+}
+
 fn configErrorHandler(type_name: []const u8, key: []const u8, value: []const u8, err: anyerror) void {
     config_errors.append(temporary_allocator, .{
         .type_name = temporary_allocator.dupe(u8, type_name) catch return,