2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3 * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
7 #include <linux/console.h>
8 #include <linux/ctype.h>
9 #include <linux/string.h>
10 #include <linux/interrupt.h>
11 #include <linux/list.h>
13 #include <linux/module.h>
14 #include <linux/notifier.h>
15 #include <linux/reboot.h>
16 #include <linux/proc_fs.h>
17 #include <linux/slab.h>
18 #include <linux/syscalls.h>
19 #include <linux/utsname.h>
20 #include <linux/socket.h>
22 #include <linux/workqueue.h>
23 #include <linux/mutex.h>
24 #include <asm/uaccess.h>
29 #include "kern_util.h"
31 #include "mconsole_kern.h"
34 static int do_unlink_socket(struct notifier_block *notifier,
35 unsigned long what, void *data)
37 return mconsole_unlink_socket();
41 static struct notifier_block reboot_notifier = {
42 .notifier_call = do_unlink_socket,
46 /* Safe without explicit locking for now. Tasklets provide their own
47 * locking, and the interrupt handler is safe because it can't interrupt
48 * itself and it can only happen on CPU 0.
51 static LIST_HEAD(mc_requests);
53 static void mc_work_proc(struct work_struct *unused)
55 struct mconsole_entry *req;
58 while (!list_empty(&mc_requests)) {
59 local_irq_save(flags);
60 req = list_entry(mc_requests.next, struct mconsole_entry, list);
62 local_irq_restore(flags);
63 req->request.cmd->handler(&req->request);
68 static DECLARE_WORK(mconsole_work, mc_work_proc);
70 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
72 /* long to avoid size mismatch warnings from gcc */
74 struct mconsole_entry *new;
75 static struct mc_request req; /* that's OK */
78 while (mconsole_get_request(fd, &req)) {
79 if (req.cmd->context == MCONSOLE_INTR)
80 (*req.cmd->handler)(&req);
82 new = kmalloc(sizeof(*new), GFP_NOWAIT);
84 mconsole_reply(&req, "Out of memory", 1, 0);
87 new->request.regs = get_irq_regs()->regs;
88 list_add(&new->list, &mc_requests);
92 if (!list_empty(&mc_requests))
93 schedule_work(&mconsole_work);
94 reactivate_fd(fd, MCONSOLE_IRQ);
98 void mconsole_version(struct mc_request *req)
102 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
103 utsname()->nodename, utsname()->release, utsname()->version,
105 mconsole_reply(req, version, 0, 0);
108 void mconsole_log(struct mc_request *req)
111 char *ptr = req->request.data;
113 ptr += strlen("log ");
115 len = req->len - (ptr - req->request.data);
116 printk(KERN_WARNING "%.*s", len, ptr);
117 mconsole_reply(req, "", 0, 0);
120 /* This is a more convoluted version of mconsole_proc, which has some stability
121 * problems; however, we need it fixed, because it is expected that UML users
122 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
123 * show the real procfs content, not the ones from hppfs.*/
125 void mconsole_proc(struct mc_request *req)
128 struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
131 char *ptr = req->request.data, *buf;
132 mm_segment_t old_fs = get_fs();
134 ptr += strlen("proc");
135 ptr = skip_spaces(ptr);
137 err = vfs_path_lookup(mnt->mnt_root, mnt, ptr, LOOKUP_FOLLOW, &nd);
139 mconsole_reply(req, "Failed to look up file", 1, 0);
143 err = may_open(&nd.path, MAY_READ, FMODE_READ);
145 mconsole_reply(req, "Failed to open file", 1, 0);
150 file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
154 mconsole_reply(req, "Failed to open file", 1, 0);
159 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
161 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
165 if (file->f_op->read) {
169 n = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
170 file_pos_write(file, pos);
174 mconsole_reply(req, buf, 0, (n > 0));
177 mconsole_reply(req, "Read of file failed",
183 else mconsole_reply(req, "", 0, 0);
193 void mconsole_proc(struct mc_request *req)
200 char *ptr = req->request.data;
202 ptr += strlen("proc");
203 ptr = skip_spaces(ptr);
204 snprintf(path, sizeof(path), "/proc/%s", ptr);
206 fd = sys_open(path, 0, 0);
208 mconsole_reply(req, "Failed to open file", 1, 0);
209 printk(KERN_ERR "open %s: %d\n",path,fd);
213 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
215 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
220 len = sys_read(fd, buf, PAGE_SIZE-1);
222 mconsole_reply(req, "Read of file failed", 1, 0);
225 /* Begin the file content on his own line. */
227 mconsole_reply(req, "\n", 0, 1);
230 if (len == PAGE_SIZE-1) {
232 mconsole_reply(req, buf, 0, 1);
235 mconsole_reply(req, buf, 0, 0);
248 #define UML_MCONSOLE_HELPTEXT \
250 version - Get kernel version \n\
251 help - Print this message \n\
253 reboot - Reboot UML \n\
254 config <dev>=<config> - Add a new device to UML; \n\
255 same syntax as command line \n\
256 config <dev> - Query the configuration of a device \n\
257 remove <dev> - Remove a device from UML \n\
258 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
259 cad - invoke the Ctrl-Alt-Del handler \n\
260 stop - pause the UML; it will do nothing until it receives a 'go' \n\
261 go - continue the UML after a 'stop' \n\
262 log <string> - make UML enter <string> into the kernel log\n\
263 proc <file> - returns the contents of the UML's /proc/<file>\n\
264 stack <pid> - returns the stack of the specified pid\n\
267 void mconsole_help(struct mc_request *req)
269 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
272 void mconsole_halt(struct mc_request *req)
274 mconsole_reply(req, "", 0, 0);
278 void mconsole_reboot(struct mc_request *req)
280 mconsole_reply(req, "", 0, 0);
281 machine_restart(NULL);
284 void mconsole_cad(struct mc_request *req)
286 mconsole_reply(req, "", 0, 0);
290 void mconsole_go(struct mc_request *req)
292 mconsole_reply(req, "Not stopped", 1, 0);
295 void mconsole_stop(struct mc_request *req)
297 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
298 os_set_fd_block(req->originating_fd, 1);
299 mconsole_reply(req, "stopped", 0, 0);
301 if (!mconsole_get_request(req->originating_fd, req))
303 if (req->cmd->handler == mconsole_go)
305 if (req->cmd->handler == mconsole_stop) {
306 mconsole_reply(req, "Already stopped", 1, 0);
309 if (req->cmd->handler == mconsole_sysrq) {
310 struct pt_regs *old_regs;
311 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
313 set_irq_regs(old_regs);
316 (*req->cmd->handler)(req);
318 os_set_fd_block(req->originating_fd, 0);
319 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
320 mconsole_reply(req, "", 0, 0);
323 static DEFINE_SPINLOCK(mc_devices_lock);
324 static LIST_HEAD(mconsole_devices);
326 void mconsole_register_dev(struct mc_device *new)
328 spin_lock(&mc_devices_lock);
329 BUG_ON(!list_empty(&new->list));
330 list_add(&new->list, &mconsole_devices);
331 spin_unlock(&mc_devices_lock);
334 static struct mc_device *mconsole_find_dev(char *name)
336 struct list_head *ele;
337 struct mc_device *dev;
339 list_for_each(ele, &mconsole_devices) {
340 dev = list_entry(ele, struct mc_device, list);
341 if (!strncmp(name, dev->name, strlen(dev->name)))
347 #define UNPLUGGED_PER_PAGE \
348 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
350 struct unplugged_pages {
351 struct list_head list;
352 void *pages[UNPLUGGED_PER_PAGE];
355 static DEFINE_MUTEX(plug_mem_mutex);
356 static unsigned long long unplugged_pages_count = 0;
357 static LIST_HEAD(unplugged_pages);
358 static int unplug_index = UNPLUGGED_PER_PAGE;
360 static int mem_config(char *str, char **error_out)
362 unsigned long long diff;
363 int err = -EINVAL, i, add;
367 *error_out = "Expected '=' after 'mem'";
374 else if (str[0] == '+') {
378 *error_out = "Expected increment to start with '-' or '+'";
383 diff = memparse(str, &ret);
385 *error_out = "Failed to parse memory increment";
391 mutex_lock(&plug_mem_mutex);
392 for (i = 0; i < diff; i++) {
393 struct unplugged_pages *unplugged;
397 if (list_empty(&unplugged_pages))
400 unplugged = list_entry(unplugged_pages.next,
401 struct unplugged_pages, list);
402 if (unplug_index > 0)
403 addr = unplugged->pages[--unplug_index];
405 list_del(&unplugged->list);
407 unplug_index = UNPLUGGED_PER_PAGE;
410 free_page((unsigned long) addr);
411 unplugged_pages_count--;
416 page = alloc_page(GFP_ATOMIC);
420 unplugged = page_address(page);
421 if (unplug_index == UNPLUGGED_PER_PAGE) {
422 list_add(&unplugged->list, &unplugged_pages);
426 struct list_head *entry = unplugged_pages.next;
429 unplugged = list_entry(entry,
430 struct unplugged_pages,
432 err = os_drop_memory(addr, PAGE_SIZE);
434 printk(KERN_ERR "Failed to release "
435 "memory - errno = %d\n", err);
436 *error_out = "Failed to release memory";
439 unplugged->pages[unplug_index++] = addr;
442 unplugged_pages_count++;
448 mutex_unlock(&plug_mem_mutex);
453 static int mem_get_config(char *name, char *str, int size, char **error_out)
455 char buf[sizeof("18446744073709551615")];
458 sprintf(buf, "%ld", uml_physmem);
459 CONFIG_CHUNK(str, size, len, buf, 1);
464 static int mem_id(char **str, int *start_out, int *end_out)
472 static int mem_remove(int n, char **error_out)
474 *error_out = "Memory doesn't support the remove operation";
478 static struct mc_device mem_mc = {
479 .list = LIST_HEAD_INIT(mem_mc.list),
481 .config = mem_config,
482 .get_config = mem_get_config,
484 .remove = mem_remove,
487 static int __init mem_mc_init(void)
489 if (can_drop_memory())
490 mconsole_register_dev(&mem_mc);
491 else printk(KERN_ERR "Can't release memory to the host - memory "
492 "hotplug won't be supported\n");
496 __initcall(mem_mc_init);
498 #define CONFIG_BUF_SIZE 64
500 static void mconsole_get_config(int (*get_config)(char *, char *, int,
502 struct mc_request *req, char *name)
504 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
507 if (get_config == NULL) {
508 mconsole_reply(req, "No get_config routine defined", 1, 0);
513 size = ARRAY_SIZE(default_buf);
517 n = (*get_config)(name, buf, size, &error);
519 mconsole_reply(req, error, 1, 0);
524 mconsole_reply(req, buf, 0, 0);
528 if (buf != default_buf)
532 buf = kmalloc(size, GFP_KERNEL);
534 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
539 if (buf != default_buf)
543 void mconsole_config(struct mc_request *req)
545 struct mc_device *dev;
546 char *ptr = req->request.data, *name, *error_string = "";
549 ptr += strlen("config");
550 ptr = skip_spaces(ptr);
551 dev = mconsole_find_dev(ptr);
553 mconsole_reply(req, "Bad configuration option", 1, 0);
557 name = &ptr[strlen(dev->name)];
559 while ((*ptr != '=') && (*ptr != '\0'))
563 err = (*dev->config)(name, &error_string);
564 mconsole_reply(req, error_string, err, 0);
566 else mconsole_get_config(dev->get_config, req, name);
569 void mconsole_remove(struct mc_request *req)
571 struct mc_device *dev;
572 char *ptr = req->request.data, *err_msg = "";
574 int err, start, end, n;
576 ptr += strlen("remove");
577 ptr = skip_spaces(ptr);
578 dev = mconsole_find_dev(ptr);
580 mconsole_reply(req, "Bad remove option", 1, 0);
584 ptr = &ptr[strlen(dev->name)];
587 n = (*dev->id)(&ptr, &start, &end);
589 err_msg = "Couldn't parse device number";
592 else if ((n < start) || (n > end)) {
593 sprintf(error, "Invalid device number - must be between "
594 "%d and %d", start, end);
600 err = (*dev->remove)(n, &err_msg);
607 err_msg = "Device doesn't exist";
611 err_msg = "Device is currently open";
617 mconsole_reply(req, err_msg, err, 0);
620 struct mconsole_output {
621 struct list_head list;
622 struct mc_request *req;
625 static DEFINE_SPINLOCK(client_lock);
626 static LIST_HEAD(clients);
627 static char console_buf[MCONSOLE_MAX_DATA];
629 static void console_write(struct console *console, const char *string,
632 struct list_head *ele;
635 if (list_empty(&clients))
639 n = min((size_t) len, ARRAY_SIZE(console_buf));
640 strncpy(console_buf, string, n);
644 list_for_each(ele, &clients) {
645 struct mconsole_output *entry;
647 entry = list_entry(ele, struct mconsole_output, list);
648 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
653 static struct console mc_console = { .name = "mc",
654 .write = console_write,
655 .flags = CON_ENABLED,
658 static int mc_add_console(void)
660 register_console(&mc_console);
664 late_initcall(mc_add_console);
666 static void with_console(struct mc_request *req, void (*proc)(void *),
669 struct mconsole_output entry;
673 spin_lock_irqsave(&client_lock, flags);
674 list_add(&entry.list, &clients);
675 spin_unlock_irqrestore(&client_lock, flags);
679 mconsole_reply_len(req, "", 0, 0, 0);
681 spin_lock_irqsave(&client_lock, flags);
682 list_del(&entry.list);
683 spin_unlock_irqrestore(&client_lock, flags);
686 #ifdef CONFIG_MAGIC_SYSRQ
688 #include <linux/sysrq.h>
690 static void sysrq_proc(void *arg)
693 handle_sysrq(*op, NULL);
696 void mconsole_sysrq(struct mc_request *req)
698 char *ptr = req->request.data;
700 ptr += strlen("sysrq");
701 ptr = skip_spaces(ptr);
704 * With 'b', the system will shut down without a chance to reply,
705 * so in this case, we reply first.
708 mconsole_reply(req, "", 0, 0);
710 with_console(req, sysrq_proc, ptr);
713 void mconsole_sysrq(struct mc_request *req)
715 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
719 static void stack_proc(void *arg)
721 struct task_struct *from = current, *to = arg;
723 to->thread.saved_task = from;
724 switch_to(from, to, from);
728 * Mconsole stack trace
729 * Added by Allan Graves, Jeff Dike
730 * Dumps a stacks registers to the linux console.
733 void mconsole_stack(struct mc_request *req)
735 char *ptr = req->request.data;
736 int pid_requested= -1;
737 struct task_struct *to = NULL;
741 * 1) Send showregs output to mconsole.
742 * 2) Add a way to stack dump all pids.
745 ptr += strlen("stack");
746 ptr = skip_spaces(ptr);
749 * Should really check for multiple pids or reject bad args here
751 /* What do the arguments in mconsole_reply mean? */
752 if (sscanf(ptr, "%d", &pid_requested) == 0) {
753 mconsole_reply(req, "Please specify a pid", 1, 0);
757 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
758 if ((to == NULL) || (pid_requested == 0)) {
759 mconsole_reply(req, "Couldn't find that pid", 1, 0);
762 with_console(req, stack_proc, to);
766 * Changed by mconsole_setup, which is __setup, and called before SMP is
769 static char *notify_socket = NULL;
771 static int __init mconsole_init(void)
773 /* long to avoid size mismatch warnings from gcc */
776 char file[UNIX_PATH_MAX];
778 if (umid_file_name("mconsole", file, sizeof(file)))
780 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
782 sock = os_create_unix_socket(file, sizeof(file), 1);
784 printk(KERN_ERR "Failed to initialize management console\n");
787 if (os_set_fd_block(sock, 0))
790 register_reboot_notifier(&reboot_notifier);
792 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
793 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
794 "mconsole", (void *)sock);
796 printk(KERN_ERR "Failed to get IRQ for management console\n");
800 if (notify_socket != NULL) {
801 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
802 if (notify_socket != NULL)
803 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
804 mconsole_socket_name,
805 strlen(mconsole_socket_name) + 1);
806 else printk(KERN_ERR "mconsole_setup failed to strdup "
810 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
811 MCONSOLE_VERSION, mconsole_socket_name);
819 __initcall(mconsole_init);
821 static ssize_t mconsole_proc_write(struct file *file,
822 const char __user *buffer, size_t count, loff_t *pos)
826 buf = kmalloc(count + 1, GFP_KERNEL);
830 if (copy_from_user(buf, buffer, count)) {
837 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
843 static const struct file_operations mconsole_proc_fops = {
844 .owner = THIS_MODULE,
845 .write = mconsole_proc_write,
848 static int create_proc_mconsole(void)
850 struct proc_dir_entry *ent;
852 if (notify_socket == NULL)
855 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
857 printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
864 static DEFINE_SPINLOCK(notify_spinlock);
866 void lock_notify(void)
868 spin_lock(¬ify_spinlock);
871 void unlock_notify(void)
873 spin_unlock(¬ify_spinlock);
876 __initcall(create_proc_mconsole);
878 #define NOTIFY "notify:"
880 static int mconsole_setup(char *str)
882 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
883 str += strlen(NOTIFY);
886 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
890 __setup("mconsole=", mconsole_setup);
892 __uml_help(mconsole_setup,
893 "mconsole=notify:<socket>\n"
894 " Requests that the mconsole driver send a message to the named Unix\n"
895 " socket containing the name of the mconsole socket. This also serves\n"
896 " to notify outside processes when UML has booted far enough to respond\n"
897 " to mconsole requests.\n\n"
900 static int notify_panic(struct notifier_block *self, unsigned long unused1,
905 if (notify_socket == NULL)
908 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
909 strlen(message) + 1);
913 static struct notifier_block panic_exit_notifier = {
914 .notifier_call = notify_panic,
919 static int add_notifier(void)
921 atomic_notifier_chain_register(&panic_notifier_list,
922 &panic_exit_notifier);
926 __initcall(add_notifier);
928 char *mconsole_notify_socket(void)
930 return notify_socket;
933 EXPORT_SYMBOL(mconsole_notify_socket);