Extended fs_shell by an interface for external scripting.

This is the first step towards getting rid of the UserlandFS dependency
for building a HD image. Which is in turn the first step to being able to
build one under Linux.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11541 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/tests/add-ons/kernel/file_systems/fs_shell/external_commands.cpp

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2005, Ingo Weinhold, bonefish@users.sf.net.
+ * Distributed under the terms of the MIT License.
+ */
+
+#include "external_commands.h"
+
+#ifdef __BEOS__
+
+#include <stdio.h>
+#include <string.h>
+
+#include <OS.h>
+
+#include "fs_shell_command_beos.h"
+
+static port_id sReplyPort = -1;
+
+static port_id
+get_command_port()
+{
+	static port_id port = -1;
+	static bool initialized = false;
+
+	if (!initialized) {
+		port = create_port(10, kFSShellCommandPort);
+		initialized = true;
+	}
+
+	return port;
+}
+
+
+char *
+get_external_command(const char *prompt, char *input, int len)
+{
+	// get/create the port
+	port_id port = get_command_port();
+	if (port < 0) {
+		fprintf(stderr, "Failed to create command port: %s\n", strerror(port));
+		return NULL;
+	}
+
+
+	while (true) {
+		// read a message
+		external_command_message message;
+		ssize_t bytesRead;
+		do {
+			int32 code;
+			bytesRead = read_port(port, &code, &message, sizeof(message));
+		} while (bytesRead == B_INTERRUPTED);
+
+		if (bytesRead < 0) {
+			fprintf(stderr, "Reading from port failed: %s\n",
+				strerror(bytesRead));
+			return NULL;
+		}
+
+		// get the len of the command
+		int commandLen = (char*)&message + bytesRead - message.command;
+		if (commandLen <= 1) {
+			fprintf(stderr, "No command given.\n");
+			continue;
+		}
+		if (commandLen > len) {
+			fprintf(stderr, "Command too long. Ignored.\n");
+			continue;
+		}
+
+		// copy the command
+		memcpy(input, message.command, commandLen);
+		input[len - 1] = '\0';	// always NULL-terminate
+		sReplyPort = message.reply_port;
+		return input;
+	}
+}
+
+
+void
+reply_to_external_command(int result)
+{
+	if (sReplyPort >= 0) {
+		// prepare the message
+		external_command_reply reply;
+		reply.error = result;
+
+		// send the reply
+		status_t error;
+		do {
+			error = write_port(sReplyPort, 0, &reply, sizeof(reply));
+		} while (error == B_INTERRUPTED);
+		sReplyPort = -1;
+
+		if (error != B_OK) {
+			fprintf(stderr, "Failed to send command result to reply port: %s\n",
+				strerror(error));
+		}
+	}
+}
+
+#endif // __BEOS__

src/tests/add-ons/kernel/file_systems/fs_shell/external_commands.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2005, Haiku Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef FS_SHELL_EXTERNAL_COMMANDS_H
+#define FS_SHELL_EXTERNAL_COMMANDS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+char *get_external_command(const char *prompt, char *input, int len);
+void reply_to_external_command(int result);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	// FS_SHELL_EXTERNAL_COMMANDS_H