* Added support for the "--help" argument to some debugger commands.

* The kernel debugger does now define some temporary variables when
  entered (current thread and team, etc.).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23549 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/arch/x86/arch_debug.cpp

@@ -233,17 +233,22 @@ get_previous_iframe(struct thread* thread, struct iframe* frame)
 static int
 stack_trace(int argc, char **argv)
 {
+	static const char* usage = "usage: %s [ <thread id> ]\n"
+		"Prints a stack trace for the current, respectively the specified\n"
+		"thread.\n"
+		"  <thread id>  -  The ID of the thread for which to print the stack\n"
+		"                  trace.\n";
+	if (argc > 2 || argc == 2 && strcmp(argv[1], "--help") == 0) {
+		kprintf(usage, argv[0]);
+		return 0;
+	}
+
 	uint32 previousLocations[NUM_PREVIOUS_LOCATIONS];
 	struct thread *thread = NULL;
 	addr_t oldPageDirectory = 0;
 	uint32 ebp = x86_read_ebp();
 	int32 i, num = 0, last = 0;
 
-	if (argc > 2) {
-		kprintf("usage: %s [thread id]\n", argv[0]);
-		return 0;
-	}
-
 	setup_for_thread(argc == 2 ? argv[1] : NULL, &thread, &ebp,
 		&oldPageDirectory);
 
@@ -363,6 +368,18 @@ print_call(struct thread *thread, addr_t eip, addr_t ebp, int32 argCount)
 static int
 show_call(int argc, char **argv)
 {
+	static const char* usage
+		= "usage: %s [ <thread id> ] <call index> [ -<arg count> ]\n"
+		"Prints a function call with parameters of the current, respectively\n"
+		"the specified thread.\n"
+		"  <thread id>   -  The ID of the thread for which to print the call.\n"
+		"  <call index>  -  The index of the call in the stack trace.\n"
+		"  <arg count>   -  The number of call arguments to print.\n";
+	if (argc == 2 && strcmp(argv[1], "--help") == 0) {
+		kprintf(usage, argv[0]);
+		return 0;
+	}
+
 	struct thread *thread = NULL;
 	addr_t oldPageDirectory = 0;
 	uint32 ebp = x86_read_ebp();
@@ -378,7 +395,7 @@ show_call(int argc, char **argv)
 	}
 
 	if (argc < 2 || argc > 3) {
-		kprintf("usage: %s [thread id] <call-index> [-<arg-count>]\n", argv[0]);
+		kprintf(usage, argv[0]);
 		return 0;
 	}
 
@@ -424,7 +441,7 @@ show_call(int argc, char **argv)
 	}
 
 	if (oldPageDirectory != 0) {
-		// switch back to the previous page directory to no cause any troubles
+		// switch back to the previous page directory to not cause any troubles
 		write_cr3(oldPageDirectory);
 	}
 
@@ -435,6 +452,16 @@ show_call(int argc, char **argv)
 static int
 dump_iframes(int argc, char **argv)
 {
+	static const char* usage = "usage: %s [ <thread id> ]\n"
+		"Prints the iframe stack for the current, respectively the specified\n"
+		"thread.\n"
+		"  <thread id>  -  The ID of the thread for which to print the iframe\n"
+		"                  stack.\n";
+	if (argc == 2 && strcmp(argv[1], "--help") == 0) {
+		kprintf(usage, argv[0]);
+		return 0;
+	}
+
 	struct thread *thread = NULL;
 	int32 i;
 
@@ -448,7 +475,7 @@ dump_iframes(int argc, char **argv)
 			return 0;
 		}
 	} else if (argc > 2) {
-		kprintf("usage: %s [thread id]\n", argv[0]);
+		kprintf(usage, argv[0]);
 		return 0;
 	}
 

src/system/kernel/debug/debug.cpp

@@ -497,6 +497,15 @@ kernel_debugger_loop(void)
 	int32 previousCPU = sDebuggerOnCPU;
 	sDebuggerOnCPU = smp_get_current_cpu();
 
+	// set a few temporary debug variables
+	if (struct thread* thread = thread_get_current_thread()) {
+		set_debug_variable("_thread", (uint64)(addr_t)thread);
+		set_debug_variable("_threadID", thread->id);
+		set_debug_variable("_team", (uint64)(addr_t)thread->team);
+		set_debug_variable("_teamID", thread->team->id);
+		set_debug_variable("_cpu", sDebuggerOnCPU);
+	}
+
 	kprintf("Welcome to Kernel Debugging Land...\n");
 	kprintf("Running on CPU %ld\n", sDebuggerOnCPU);
 
@@ -549,6 +558,13 @@ 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! ;-)
@@ -558,6 +574,13 @@ 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;
 }
@@ -566,6 +589,13 @@ cmd_shutdown(int argc, char **argv)
 static int
 cmd_help(int argc, char **argv)
 {
+	static const char* usage = "usage: %s\n"
+		"Lists all debugger commands.\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;
@@ -604,6 +634,13 @@ 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;
 }
 
@@ -611,6 +648,13 @@ 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');
@@ -622,10 +666,10 @@ cmd_dump_kdl_message(int argc, char **argv)
 static int
 cmd_expr(int argc, char **argv)
 {
-	static const char* usage = "usage: expr <expression>\n"
+	static const char* usage = "usage: %s <expression>\n"
 		"Evaluates the given expression and prints the result.\n";
 	if (argc != 2 || strcmp(argv[1], "--help") == 0) {
-		kprintf(usage);
+		kprintf(usage, argv[0]);
 		return 0;
 	}