mconsole_kern.c

来自「LINUX 2.6.17.4的源码」· C语言 代码 · 共 914 行 · 第 1/2 页

	*end_out = 0;

	return 0;
}

static int mem_remove(int n)
{
	return -EBUSY;
}

static struct mc_device mem_mc = {
	.name		= "mem",
	.config		= mem_config,
	.get_config	= mem_get_config,
	.id		= mem_id,
	.remove		= mem_remove,
};

static int mem_mc_init(void)
{
	if(can_drop_memory())
		mconsole_register_dev(&mem_mc);
	else printk("Can't release memory to the host - memory hotplug won't "
		    "be supported\n");
	return 0;
}

__initcall(mem_mc_init);

#define CONFIG_BUF_SIZE 64

static void mconsole_get_config(int (*get_config)(char *, char *, int,
						  char **),
				struct mc_request *req, char *name)
{
	char default_buf[CONFIG_BUF_SIZE], *error, *buf;
	int n, size;

	if(get_config == NULL){
		mconsole_reply(req, "No get_config routine defined", 1, 0);
		return;
	}

	error = NULL;
	size = sizeof(default_buf)/sizeof(default_buf[0]);
	buf = default_buf;

	while(1){
		n = (*get_config)(name, buf, size, &error);
		if(error != NULL){
			mconsole_reply(req, error, 1, 0);
			goto out;
		}

		if(n <= size){
			mconsole_reply(req, buf, 0, 0);
			goto out;
		}

		if(buf != default_buf)
			kfree(buf);

		size = n;
		buf = kmalloc(size, GFP_KERNEL);
		if(buf == NULL){
			mconsole_reply(req, "Failed to allocate buffer", 1, 0);
			return;
		}
	}
 out:
	if(buf != default_buf)
		kfree(buf);
}

void mconsole_config(struct mc_request *req)
{
	struct mc_device *dev;
	char *ptr = req->request.data, *name;
	int err;

	ptr += strlen("config");
	while(isspace(*ptr)) ptr++;
	dev = mconsole_find_dev(ptr);
	if(dev == NULL){
		mconsole_reply(req, "Bad configuration option", 1, 0);
		return;
	}

	name = &ptr[strlen(dev->name)];
	ptr = name;
	while((*ptr != '=') && (*ptr != '\0'))
		ptr++;

	if(*ptr == '='){
		err = (*dev->config)(name);
		mconsole_reply(req, "", err, 0);
	}
	else mconsole_get_config(dev->get_config, req, name);
}

void mconsole_remove(struct mc_request *req)
{
	struct mc_device *dev;
	char *ptr = req->request.data, *err_msg = "";
	char error[256];
	int err, start, end, n;

	ptr += strlen("remove");
	while(isspace(*ptr)) ptr++;
	dev = mconsole_find_dev(ptr);
	if(dev == NULL){
		mconsole_reply(req, "Bad remove option", 1, 0);
		return;
	}

	ptr = &ptr[strlen(dev->name)];

	err = 1;
	n = (*dev->id)(&ptr, &start, &end);
	if(n < 0){
		err_msg = "Couldn't parse device number";
		goto out;
	}
	else if((n < start) || (n > end)){
		sprintf(error, "Invalid device number - must be between "
			"%d and %d", start, end);
		err_msg = error;
		goto out;
	}

	err = (*dev->remove)(n);
	switch(err){
	case -ENODEV:
		err_msg = "Device doesn't exist";
		break;
	case -EBUSY:
		err_msg = "Device is currently open";
		break;
	default:
		break;
	}
out:
	mconsole_reply(req, err_msg, err, 0);
}

static DEFINE_SPINLOCK(console_lock);
static LIST_HEAD(clients);
static char console_buf[MCONSOLE_MAX_DATA];
static int console_index = 0;

static void console_write(struct console *console, const char *string,
			  unsigned len)
{
	struct list_head *ele;
	int n;

	if(list_empty(&clients))
		return;

	while(1){
		n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
		strncpy(&console_buf[console_index], string, n);
		console_index += n;
		string += n;
		len -= n;
		if(len == 0)
			return;

		list_for_each(ele, &clients){
			struct mconsole_entry *entry;

			entry = list_entry(ele, struct mconsole_entry, list);
			mconsole_reply_len(&entry->request, console_buf,
					   console_index, 0, 1);
		}

		console_index = 0;
	}
}

static struct console mc_console = { .name	= "mc",
				     .write	= console_write,
				     .flags	= CON_ENABLED,
				     .index	= -1 };

static int mc_add_console(void)
{
	register_console(&mc_console);
	return 0;
}

late_initcall(mc_add_console);

static void with_console(struct mc_request *req, void (*proc)(void *),
			 void *arg)
{
	struct mconsole_entry entry;
	unsigned long flags;

	entry.request = *req;
	list_add(&entry.list, &clients);
	spin_lock_irqsave(&console_lock, flags);

	(*proc)(arg);

	mconsole_reply_len(req, console_buf, console_index, 0, 0);
	console_index = 0;

	spin_unlock_irqrestore(&console_lock, flags);
	list_del(&entry.list);
}

#ifdef CONFIG_MAGIC_SYSRQ
static void sysrq_proc(void *arg)
{
	char *op = arg;

	handle_sysrq(*op, &current->thread.regs, NULL);
}

void mconsole_sysrq(struct mc_request *req)
{
	char *ptr = req->request.data;

	ptr += strlen("sysrq");
	while(isspace(*ptr)) ptr++;

	/* With 'b', the system will shut down without a chance to reply,
	 * so in this case, we reply first.
	 */
	if(*ptr == 'b')
		mconsole_reply(req, "", 0, 0);

	with_console(req, sysrq_proc, ptr);
}
#else
void mconsole_sysrq(struct mc_request *req)
{
	mconsole_reply(req, "Sysrq not compiled in", 1, 0);
}
#endif

#ifdef CONFIG_MODE_SKAS

static void stack_proc(void *arg)
{
	struct task_struct *from = current, *to = arg;

	to->thread.saved_task = from;
	switch_to(from, to, from);
}

/* Mconsole stack trace
 *  Added by Allan Graves, Jeff Dike
 *  Dumps a stacks registers to the linux console.
 *  Usage stack <pid>.
 */
static void do_stack_trace(struct mc_request *req)
{
	char *ptr = req->request.data;
	int pid_requested= -1;
	struct task_struct *from = NULL;
	struct task_struct *to = NULL;

	/* Would be nice:
	 * 1) Send showregs output to mconsole.
	 * 2) Add a way to stack dump all pids.
	 */

	ptr += strlen("stack");
	while(isspace(*ptr)) ptr++;

	/* Should really check for multiple pids or reject bad args here */
	/* What do the arguments in mconsole_reply mean? */
	if(sscanf(ptr, "%d", &pid_requested) == 0){
		mconsole_reply(req, "Please specify a pid", 1, 0);
		return;
	}

	from = current;

	to = find_task_by_pid(pid_requested);
	if((to == NULL) || (pid_requested == 0)) {
		mconsole_reply(req, "Couldn't find that pid", 1, 0);
		return;
	}
	with_console(req, stack_proc, to);
}
#endif /* CONFIG_MODE_SKAS */

void mconsole_stack(struct mc_request *req)
{
	/* This command doesn't work in TT mode, so let's check and then
	 * get out of here
	 */
	CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
				   1, 0),
		    do_stack_trace(req));
}

/* Changed by mconsole_setup, which is __setup, and called before SMP is
 * active.
 */
static char *notify_socket = NULL;

static int mconsole_init(void)
{
	/* long to avoid size mismatch warnings from gcc */
	long sock;
	int err;
	char file[256];

	if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
	snprintf(mconsole_socket_name, sizeof(file), "%s", file);

	sock = os_create_unix_socket(file, sizeof(file), 1);
	if (sock < 0){
		printk("Failed to initialize management console\n");
		return(1);
	}

	register_reboot_notifier(&reboot_notifier);

	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
			     SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
			     "mconsole", (void *)sock);
	if (err){
		printk("Failed to get IRQ for management console\n");
		return(1);
	}

	if(notify_socket != NULL){
		notify_socket = kstrdup(notify_socket, GFP_KERNEL);
		if(notify_socket != NULL)
			mconsole_notify(notify_socket, MCONSOLE_SOCKET,
					mconsole_socket_name,
					strlen(mconsole_socket_name) + 1);
		else printk(KERN_ERR "mconsole_setup failed to strdup "
			    "string\n");
	}

	printk("mconsole (version %d) initialized on %s\n",
	       MCONSOLE_VERSION, mconsole_socket_name);
	return(0);
}

__initcall(mconsole_init);

static int write_proc_mconsole(struct file *file, const char __user *buffer,
			       unsigned long count, void *data)
{
	char *buf;

	buf = kmalloc(count + 1, GFP_KERNEL);
	if(buf == NULL)
		return(-ENOMEM);

	if(copy_from_user(buf, buffer, count)){
		count = -EFAULT;
		goto out;
	}

	buf[count] = '\0';

	mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
 out:
	kfree(buf);
	return(count);
}

static int create_proc_mconsole(void)
{
	struct proc_dir_entry *ent;

	if(notify_socket == NULL) return(0);

	ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
	if(ent == NULL){
		printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
		return(0);
	}

	ent->read_proc = NULL;
	ent->write_proc = write_proc_mconsole;
	return(0);
}

static DEFINE_SPINLOCK(notify_spinlock);

void lock_notify(void)
{
	spin_lock(&notify_spinlock);
}

void unlock_notify(void)
{
	spin_unlock(&notify_spinlock);
}

__initcall(create_proc_mconsole);

#define NOTIFY "=notify:"

static int mconsole_setup(char *str)
{
	if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
		str += strlen(NOTIFY);
		notify_socket = str;
	}
	else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
	return(1);
}

__setup("mconsole", mconsole_setup);

__uml_help(mconsole_setup,
"mconsole=notify:<socket>\n"
"    Requests that the mconsole driver send a message to the named Unix\n"
"    socket containing the name of the mconsole socket.  This also serves\n"
"    to notify outside processes when UML has booted far enough to respond\n"
"    to mconsole requests.\n\n"
);

static int notify_panic(struct notifier_block *self, unsigned long unused1,
			void *ptr)
{
	char *message = ptr;

	if(notify_socket == NULL) return(0);

	mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
			strlen(message) + 1);
	return(0);
}

static struct notifier_block panic_exit_notifier = {
	.notifier_call 		= notify_panic,
	.next 			= NULL,
	.priority 		= 1
};

static int add_notifier(void)
{
	atomic_notifier_chain_register(&panic_notifier_list,
			&panic_exit_notifier);
	return(0);
}

__initcall(add_notifier);

char *mconsole_notify_socket(void)
{
	return(notify_socket);
}

EXPORT_SYMBOL(mconsole_notify_socket);