New debugging commands.

kern/main/menu.c

@@ -35,6 +35,8 @@
 #include <lib.h>
 #include <uio.h>
 #include <clock.h>
+#include <mainbus.h>
+#include <synch.h>
 #include <thread.h>
 #include <proc.h>
 #include <vfs.h>
@@ -237,6 +239,21 @@ cmd_sync(int nargs, char **args)
 	return 0;
 }
 
+/*
+ * Command for dropping to the debugger.
+ */
+static
+int
+cmd_debug(int nargs, char **args)
+{
+	(void)nargs;
+	(void)args;
+
+	mainbus_debugger();
+
+	return 0;
+}
+
 /*
  * Command for doing an intentional panic.
  */
@@ -251,6 +268,81 @@ cmd_panic(int nargs, char **args)
 	return 0;
 }
 
+/*
+ * Subthread for intentially deadlocking.
+ */
+struct deadlock {
+	struct lock *lock1;
+	struct lock *lock2;
+};
+
+static
+void
+cmd_deadlockthread(void *ptr, unsigned long num)
+{
+	struct deadlock *dl = ptr;
+
+	(void)num;
+
+	/* If it doesn't wedge right away, keep trying... */
+	while (1) {
+		lock_acquire(dl->lock2);
+		lock_acquire(dl->lock1);
+		kprintf("+");
+		lock_release(dl->lock1);
+		lock_release(dl->lock2);
+	}
+}
+
+/*
+ * Command for doing an intentional deadlock.
+ */
+static
+int
+cmd_deadlock(int nargs, char **args)
+{
+	struct deadlock dl;
+	int result;
+
+	(void)nargs;
+	(void)args;
+
+	dl.lock1 = lock_create("deadlock1");
+	if (dl.lock1 == NULL) {
+		kprintf("lock_create failed\n");
+		return ENOMEM;
+	}
+	dl.lock2 = lock_create("deadlock2");
+	if (dl.lock2 == NULL) {
+		lock_destroy(dl.lock1);
+		kprintf("lock_create failed\n");
+		return ENOMEM;
+	}
+
+	result = thread_fork(args[0] /* thread name */,
+			NULL /* kernel thread */,
+			cmd_deadlockthread /* thread function */,
+			&dl /* thread arg */, 0 /* thread arg */);
+	if (result) {
+		kprintf("thread_fork failed: %s\n", strerror(result));
+		lock_release(dl.lock1);
+		lock_destroy(dl.lock2);
+		lock_destroy(dl.lock1);
+		return result;
+	}
+
+	/* If it doesn't wedge right away, keep trying... */
+	while (1) {
+		lock_acquire(dl.lock1);
+		lock_acquire(dl.lock2);
+		kprintf(".");
+		lock_release(dl.lock2);
+		lock_release(dl.lock1);
+	}
+	/* NOTREACHED */
+	return 0;
+}
+
 /*
  * Command for shutting down.
  */
@@ -441,7 +533,9 @@ static const char *opsmenu[] = {
 	"[cd]      Change directory          ",
 	"[pwd]     Print current directory   ",
 	"[sync]    Sync filesystems          ",
+	"[debug]   Drop to debugger          ",
 	"[panic]   Intentional panic         ",
+	"[deadlock] Intentional deadlock     ",
 	"[q]       Quit and shut down        ",
 	NULL
 };
@@ -547,7 +641,9 @@ static struct {
 	{ "cd",		cmd_chdir },
 	{ "pwd",	cmd_pwd },
 	{ "sync",	cmd_sync },
+	{ "debug",	cmd_debug },
 	{ "panic",	cmd_panic },
+	{ "deadlock",	cmd_deadlock },
 	{ "q",		cmd_quit },
 	{ "exit",	cmd_quit },
 	{ "halt",	cmd_quit },