* Added add_debugger_command_etc() which is similar to

add_debugger_command(), but additionally takes parameters "usage"
  and "flags".
* Added add_debugger_command_alias() which creates another name for an
  existing command.
* Added print_debugger_command_usage() to print a command's usage.
* invoke_debugger_command() intercepts invocations with "--help" and
  prints the command's usage text, if it is known. If unknown, the
  command will be called normally.
* Made use of the new functions in debug.cpp.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23573 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/debug.h

@@ -70,6 +70,13 @@ extern bool		evaluate_debug_expression(const char* expression,
 					uint64* result, bool silent);
 extern int		evaluate_debug_command(const char* command);
 
+extern status_t	add_debugger_command_etc(const char* name,
+					debugger_command_hook func, const char* description,
+					const char* usage, uint32 flags);
+extern status_t	add_debugger_command_alias(const char* newName,
+					const char* oldName, const char* description);
+extern bool		print_debugger_command_usage(const char* command);
+
 extern void		_user_debug_output(const char *userString);
 
 #ifdef __cplusplus

src/system/kernel/debug/debug.cpp

@@ -204,9 +204,7 @@ public:
 
 			if (command != NULL) {
 				kputchar('\n');
-
+				print_debugger_command_usage(command->name);
-				char* args[3] = { NULL, "--help", NULL };
-				invoke_debugger_command(command, 2, args);
 			} else {
 				if (ambiguous)
 					kprintf("\nambiguous command\n");
@@ -558,13 +556,6 @@ kernel_debugger_loop(void)
 static int
 cmd_reboot(int argc, char **argv)
 {
-	static const char* usage = "usage: %s\n"
-		"Reboots the system.\n";
-	if (argc > 1 && strcmp(argv[1], "--help") == 0) {
-		kprintf(usage, argv[0]);
-		return 0;
-	}
-
 	arch_cpu_shutdown(true);
 	return 0;
 		// I'll be really suprised if this line ever runs! ;-)
@@ -574,13 +565,6 @@ cmd_reboot(int argc, char **argv)
 static int
 cmd_shutdown(int argc, char **argv)
 {
-	static const char* usage = "usage: %s\n"
-		"Shuts down the system.\n";
-	if (argc > 1 && strcmp(argv[1], "--help") == 0) {
-		kprintf(usage, argv[0]);
-		return 0;
-	}
-
 	arch_cpu_shutdown(false);
 	return 0;
 }
@@ -589,13 +573,6 @@ cmd_shutdown(int argc, char **argv)
 static int
 cmd_help(int argc, char **argv)
 {
-	static const char* usage = "usage: %s [name]\n"
-		"Lists all debugger commands or those starting with \"name\".\n";
-	if (argc > 1 && strcmp(argv[1], "--help") == 0) {
-		kprintf(usage, argv[0]);
-		return 0;
-	}
-
 	debugger_command *command, *specified = NULL;
 	const char *start = NULL;
 	int32 startLength = 0;
@@ -634,13 +611,6 @@ cmd_help(int argc, char **argv)
 static int
 cmd_continue(int argc, char **argv)
 {
-	static const char* usage = "usage: %s\n"
-		"Leaves kernel debugger.\n";
-	if (argc > 1 && strcmp(argv[1], "--help") == 0) {
-		kprintf(usage, argv[0]);
-		return 0;
-	}
-
 	return B_KDEBUG_QUIT;
 }
 
@@ -648,13 +618,6 @@ cmd_continue(int argc, char **argv)
 static int
 cmd_dump_kdl_message(int argc, char **argv)
 {
-	static const char* usage = "usage: %s\n"
-		"Reprints the message printed when entering KDL.\n";
-	if (argc > 1 && strcmp(argv[1], "--help") == 0) {
-		kprintf(usage, argv[0]);
-		return 0;
-	}
-
 	if (sCurrentKernelDebuggerMessage) {
 		kputs(sCurrentKernelDebuggerMessage);
 		kputchar('\n');
@@ -666,10 +629,8 @@ cmd_dump_kdl_message(int argc, char **argv)
 static int
 cmd_expr(int argc, char **argv)
 {
-	static const char* usage = "usage: %s <expression>\n"
+	if (argc != 2) {
-		"Evaluates the given expression and prints the result.\n";
+		print_debugger_command_usage(argv[0]);
-	if (argc != 2 || strcmp(argv[1], "--help") == 0) {
-		kprintf(usage, argv[0]);
 		return 0;
 	}
 
@@ -917,19 +878,31 @@ debug_init(kernel_args *args)
 status_t
 debug_init_post_vm(kernel_args *args)
 {
-	void *handle;
+	add_debugger_command_etc("help", &cmd_help, "List all debugger commands",
-
+		"usage: %s [name]\n"
-	add_debugger_command("help", &cmd_help, "List all debugger commands");
+		"Lists all debugger commands or those starting with \"name\".\n", 0);
-	add_debugger_command("reboot", &cmd_reboot, "Reboot the system");
+	add_debugger_command_etc("reboot", &cmd_reboot, "Reboot the system",
-	add_debugger_command("shutdown", &cmd_shutdown, "Shut down the system");
+		"usage: %s\n"
-	add_debugger_command("gdb", &cmd_gdb, "Connect to remote gdb");
+		"Reboots the system.\n", 0);
-	add_debugger_command("exit", &cmd_continue, "Same as \"continue\"");
+	add_debugger_command_etc("shutdown", &cmd_shutdown, "Shut down the system",
-	add_debugger_command("es", &cmd_continue, "Same as \"continue\"");
+		"usage: %s\n"
-	add_debugger_command("continue", &cmd_continue, "Leave kernel debugger");
+		"Shuts down the system.\n", 0);
-	add_debugger_command("message", &cmd_dump_kdl_message,
+	add_debugger_command_etc("gdb", &cmd_gdb, "Connect to remote gdb",
-		"Reprint the message printed when entering KDL");
+		"usage: %s\n"
-	add_debugger_command("expr", &cmd_expr,
+		"Connects to a remote gdb connected to the serial port.\n", 0);
-		"Evaluates the given expression and prints the result");
+	add_debugger_command_etc("continue", &cmd_continue, "Leave kernel debugger",
+		"usage: %s\n"
+		"Leaves kernel debugger.\n", 0);
+	add_debugger_command_alias("exit", "continue", "Same as \"continue\"");
+	add_debugger_command_alias("es", "continue", "Same as \"continue\"");
+	add_debugger_command_etc("message", &cmd_dump_kdl_message,
+		"Reprint the message printed when entering KDL",
+		"usage: %s\n"
+		"Reprints the message printed when entering KDL.\n", 0);
+	add_debugger_command_etc("expr", &cmd_expr,
+		"Evaluates the given expression and prints the result",
+		"usage: %s <expression>\n"
+		"Evaluates the given expression and prints the result.\n", 0);
 
 	debug_variables_init();
 	frame_buffer_console_init(args);
@@ -937,7 +910,7 @@ debug_init_post_vm(kernel_args *args)
 	tracing_init();
 
 	// get debug settings
-	handle = load_driver_settings("kernel");
+	void *handle = load_driver_settings("kernel");
 	if (handle != NULL) {
 		sSerialDebugEnabled = get_driver_boolean_parameter(handle,
 			"serial_debug_output", sSerialDebugEnabled, sSerialDebugEnabled);

src/system/kernel/debug/debug_commands.cpp

@@ -17,6 +17,7 @@
 #include <debug.h>
 #include <lock.h>
 #include <thread.h>
+#include <util/AutoLock.h>
 
 #include "debug_variables.h"
 
@@ -94,6 +95,14 @@ in_command_invocation(void)
 int
 invoke_debugger_command(struct debugger_command *command, int argc, char** argv)
 {
+	// intercept invocations with "--help" and directly print the usage text
+	// If we know the command's usage text, intercept "--help" invocations
+	// and print it directly.
+	if (argc == 2 && strcmp(argv[1], "--help") == 0 && command->usage != NULL) {
+		kprintf(command->usage, command->name);
+		return 0;
+	}
+
 	struct thread* thread = thread_get_current_thread();
 	addr_t oldFaultHandler = thread->fault_handler;
 
@@ -168,33 +177,79 @@ sort_debugger_commands()
 }
 
 
+status_t
+add_debugger_command_etc(const char* name, debugger_command_hook func,
+	const char* description, const char* usage, uint32 flags)
+{
+	struct debugger_command *cmd;
+
+	cmd = (struct debugger_command*)malloc(sizeof(struct debugger_command));
+	if (cmd == NULL)
+		return B_NO_MEMORY;
+
+	cmd->func = func;
+	cmd->name = name;
+	cmd->description = description;
+	cmd->usage = usage;
+	cmd->flags = flags;
+
+	InterruptsSpinLocker _(sSpinlock);
+
+	cmd->next = sCommands;
+	sCommands = cmd;
+
+	return B_OK;
+}
+
+
+status_t
+add_debugger_command_alias(const char* newName, const char* oldName,
+	const char* description)
+{
+	// get the old command
+	bool ambiguous;
+	debugger_command* command = find_debugger_command(oldName, false,
+		ambiguous);
+	if (command == NULL)
+		return B_NAME_NOT_FOUND;
+
+	// register new command
+	return add_debugger_command_etc(newName, command->func,
+		description != NULL ? description : command->description,
+		command->usage, command->flags);
+}
+
+
+bool
+print_debugger_command_usage(const char* commandName)
+{
+	// get the command
+	bool ambiguous;
+	debugger_command* command = find_debugger_command(commandName, true,
+		ambiguous);
+	if (command == NULL)
+		return false;
+
+	// directly print the usage text, if we know it, otherwise invoke the
+	// command with "--help"
+	if (command->usage != NULL) {
+		kprintf(command->usage, command->name);
+	} else {
+		char* args[3] = { NULL, "--help", NULL };
+		invoke_debugger_command(command, 2, args);
+	}
+
+	return true;
+}
+
+
 //	#pragma mark - public API
 
 
 int
 add_debugger_command(char *name, int (*func)(int, char **), char *desc)
 {
-	cpu_status state;
+	return add_debugger_command_etc(name, func, desc, NULL, 0);
-	struct debugger_command *cmd;
-
-	cmd = (struct debugger_command *)malloc(sizeof(struct debugger_command));
-	if (cmd == NULL)
-		return ENOMEM;
-
-	cmd->func = func;
-	cmd->name = name;
-	cmd->description = desc;
-
-	state = disable_interrupts();
-	acquire_spinlock(&sSpinlock);
-
-	cmd->next = sCommands;
-	sCommands = cmd;
-
-	release_spinlock(&sSpinlock);
-	restore_interrupts(state);
-
-	return B_NO_ERROR;
 }
 
 

src/system/kernel/debug/debug_commands.h

@@ -10,10 +10,12 @@
 
 
 struct debugger_command {
-	struct debugger_command *next;
+	struct debugger_command* next;
 	int				(*func)(int, char **);
-	const char *name;
+	const char*		name;
-	const char *description;
+	const char*		description;
+	const char*		usage;
+	uint32			flags;
 };
 
 #ifdef __cplusplus