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/sched/debug.h>
17 #include <linux/proc_fs.h>
18 #include <linux/slab.h>
19 #include <linux/syscalls.h>
20 #include <linux/utsname.h>
21 #include <linux/socket.h>
23 #include <linux/workqueue.h>
24 #include <linux/mutex.h>
26 #include <linux/mount.h>
27 #include <linux/file.h>
28 #include <linux/uaccess.h>
29 #include <asm/switch_to.h>
34 #include <kern_util.h>
36 #include "mconsole_kern.h"
39 static int do_unlink_socket(struct notifier_block *notifier,
40 unsigned long what, void *data)
42 return mconsole_unlink_socket();
46 static struct notifier_block reboot_notifier = {
47 .notifier_call = do_unlink_socket,
51 /* Safe without explicit locking for now. Tasklets provide their own
52 * locking, and the interrupt handler is safe because it can't interrupt
53 * itself and it can only happen on CPU 0.
56 static LIST_HEAD(mc_requests);
58 static void mc_work_proc(struct work_struct *unused)
60 struct mconsole_entry *req;
63 while (!list_empty(&mc_requests)) {
64 local_irq_save(flags);
65 req = list_entry(mc_requests.next, struct mconsole_entry, list);
67 local_irq_restore(flags);
68 req->request.cmd->handler(&req->request);
73 static DECLARE_WORK(mconsole_work, mc_work_proc);
75 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
77 /* long to avoid size mismatch warnings from gcc */
79 struct mconsole_entry *new;
80 static struct mc_request req; /* that's OK */
83 while (mconsole_get_request(fd, &req)) {
84 if (req.cmd->context == MCONSOLE_INTR)
85 (*req.cmd->handler)(&req);
87 new = kmalloc(sizeof(*new), GFP_NOWAIT);
89 mconsole_reply(&req, "Out of memory", 1, 0);
92 new->request.regs = get_irq_regs()->regs;
93 list_add(&new->list, &mc_requests);
97 if (!list_empty(&mc_requests))
98 schedule_work(&mconsole_work);
99 reactivate_fd(fd, MCONSOLE_IRQ);
103 void mconsole_version(struct mc_request *req)
107 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
108 utsname()->nodename, utsname()->release, utsname()->version,
110 mconsole_reply(req, version, 0, 0);
113 void mconsole_log(struct mc_request *req)
116 char *ptr = req->request.data;
118 ptr += strlen("log ");
120 len = req->len - (ptr - req->request.data);
121 printk(KERN_WARNING "%.*s", len, ptr);
122 mconsole_reply(req, "", 0, 0);
125 void mconsole_proc(struct mc_request *req)
127 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
132 char *ptr = req->request.data;
135 ptr += strlen("proc");
136 ptr = skip_spaces(ptr);
138 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
140 mconsole_reply(req, "Failed to open file", 1, 0);
141 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
145 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
147 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
152 len = kernel_read(file, buf, PAGE_SIZE - 1, &pos);
154 mconsole_reply(req, "Read of file failed", 1, 0);
157 /* Begin the file content on his own line. */
159 mconsole_reply(req, "\n", 0, 1);
163 mconsole_reply(req, buf, 0, (len > 0));
172 #define UML_MCONSOLE_HELPTEXT \
174 version - Get kernel version \n\
175 help - Print this message \n\
177 reboot - Reboot UML \n\
178 config <dev>=<config> - Add a new device to UML; \n\
179 same syntax as command line \n\
180 config <dev> - Query the configuration of a device \n\
181 remove <dev> - Remove a device from UML \n\
182 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
183 cad - invoke the Ctrl-Alt-Del handler \n\
184 stop - pause the UML; it will do nothing until it receives a 'go' \n\
185 go - continue the UML after a 'stop' \n\
186 log <string> - make UML enter <string> into the kernel log\n\
187 proc <file> - returns the contents of the UML's /proc/<file>\n\
188 stack <pid> - returns the stack of the specified pid\n\
191 void mconsole_help(struct mc_request *req)
193 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
196 void mconsole_halt(struct mc_request *req)
198 mconsole_reply(req, "", 0, 0);
202 void mconsole_reboot(struct mc_request *req)
204 mconsole_reply(req, "", 0, 0);
205 machine_restart(NULL);
208 void mconsole_cad(struct mc_request *req)
210 mconsole_reply(req, "", 0, 0);
214 void mconsole_go(struct mc_request *req)
216 mconsole_reply(req, "Not stopped", 1, 0);
219 void mconsole_stop(struct mc_request *req)
222 os_set_fd_block(req->originating_fd, 1);
223 mconsole_reply(req, "stopped", 0, 0);
225 if (!mconsole_get_request(req->originating_fd, req))
227 if (req->cmd->handler == mconsole_go)
229 if (req->cmd->handler == mconsole_stop) {
230 mconsole_reply(req, "Already stopped", 1, 0);
233 if (req->cmd->handler == mconsole_sysrq) {
234 struct pt_regs *old_regs;
235 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
237 set_irq_regs(old_regs);
240 (*req->cmd->handler)(req);
242 os_set_fd_block(req->originating_fd, 0);
243 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
244 mconsole_reply(req, "", 0, 0);
248 static DEFINE_SPINLOCK(mc_devices_lock);
249 static LIST_HEAD(mconsole_devices);
251 void mconsole_register_dev(struct mc_device *new)
253 spin_lock(&mc_devices_lock);
254 BUG_ON(!list_empty(&new->list));
255 list_add(&new->list, &mconsole_devices);
256 spin_unlock(&mc_devices_lock);
259 static struct mc_device *mconsole_find_dev(char *name)
261 struct list_head *ele;
262 struct mc_device *dev;
264 list_for_each(ele, &mconsole_devices) {
265 dev = list_entry(ele, struct mc_device, list);
266 if (!strncmp(name, dev->name, strlen(dev->name)))
272 #define UNPLUGGED_PER_PAGE \
273 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
275 struct unplugged_pages {
276 struct list_head list;
277 void *pages[UNPLUGGED_PER_PAGE];
280 static DEFINE_MUTEX(plug_mem_mutex);
281 static unsigned long long unplugged_pages_count = 0;
282 static LIST_HEAD(unplugged_pages);
283 static int unplug_index = UNPLUGGED_PER_PAGE;
285 static int mem_config(char *str, char **error_out)
287 unsigned long long diff;
288 int err = -EINVAL, i, add;
292 *error_out = "Expected '=' after 'mem'";
299 else if (str[0] == '+') {
303 *error_out = "Expected increment to start with '-' or '+'";
308 diff = memparse(str, &ret);
310 *error_out = "Failed to parse memory increment";
316 mutex_lock(&plug_mem_mutex);
317 for (i = 0; i < diff; i++) {
318 struct unplugged_pages *unplugged;
322 if (list_empty(&unplugged_pages))
325 unplugged = list_entry(unplugged_pages.next,
326 struct unplugged_pages, list);
327 if (unplug_index > 0)
328 addr = unplugged->pages[--unplug_index];
330 list_del(&unplugged->list);
332 unplug_index = UNPLUGGED_PER_PAGE;
335 free_page((unsigned long) addr);
336 unplugged_pages_count--;
341 page = alloc_page(GFP_ATOMIC);
345 unplugged = page_address(page);
346 if (unplug_index == UNPLUGGED_PER_PAGE) {
347 list_add(&unplugged->list, &unplugged_pages);
351 struct list_head *entry = unplugged_pages.next;
354 unplugged = list_entry(entry,
355 struct unplugged_pages,
357 err = os_drop_memory(addr, PAGE_SIZE);
359 printk(KERN_ERR "Failed to release "
360 "memory - errno = %d\n", err);
361 *error_out = "Failed to release memory";
364 unplugged->pages[unplug_index++] = addr;
367 unplugged_pages_count++;
373 mutex_unlock(&plug_mem_mutex);
378 static int mem_get_config(char *name, char *str, int size, char **error_out)
380 char buf[sizeof("18446744073709551615")];
383 sprintf(buf, "%ld", uml_physmem);
384 CONFIG_CHUNK(str, size, len, buf, 1);
389 static int mem_id(char **str, int *start_out, int *end_out)
397 static int mem_remove(int n, char **error_out)
399 *error_out = "Memory doesn't support the remove operation";
403 static struct mc_device mem_mc = {
404 .list = LIST_HEAD_INIT(mem_mc.list),
406 .config = mem_config,
407 .get_config = mem_get_config,
409 .remove = mem_remove,
412 static int __init mem_mc_init(void)
414 if (can_drop_memory())
415 mconsole_register_dev(&mem_mc);
416 else printk(KERN_ERR "Can't release memory to the host - memory "
417 "hotplug won't be supported\n");
421 __initcall(mem_mc_init);
423 #define CONFIG_BUF_SIZE 64
425 static void mconsole_get_config(int (*get_config)(char *, char *, int,
427 struct mc_request *req, char *name)
429 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
432 if (get_config == NULL) {
433 mconsole_reply(req, "No get_config routine defined", 1, 0);
438 size = ARRAY_SIZE(default_buf);
442 n = (*get_config)(name, buf, size, &error);
444 mconsole_reply(req, error, 1, 0);
449 mconsole_reply(req, buf, 0, 0);
453 if (buf != default_buf)
457 buf = kmalloc(size, GFP_KERNEL);
459 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
464 if (buf != default_buf)
468 void mconsole_config(struct mc_request *req)
470 struct mc_device *dev;
471 char *ptr = req->request.data, *name, *error_string = "";
474 ptr += strlen("config");
475 ptr = skip_spaces(ptr);
476 dev = mconsole_find_dev(ptr);
478 mconsole_reply(req, "Bad configuration option", 1, 0);
482 name = &ptr[strlen(dev->name)];
484 while ((*ptr != '=') && (*ptr != '\0'))
488 err = (*dev->config)(name, &error_string);
489 mconsole_reply(req, error_string, err, 0);
491 else mconsole_get_config(dev->get_config, req, name);
494 void mconsole_remove(struct mc_request *req)
496 struct mc_device *dev;
497 char *ptr = req->request.data, *err_msg = "";
499 int err, start, end, n;
501 ptr += strlen("remove");
502 ptr = skip_spaces(ptr);
503 dev = mconsole_find_dev(ptr);
505 mconsole_reply(req, "Bad remove option", 1, 0);
509 ptr = &ptr[strlen(dev->name)];
512 n = (*dev->id)(&ptr, &start, &end);
514 err_msg = "Couldn't parse device number";
517 else if ((n < start) || (n > end)) {
518 sprintf(error, "Invalid device number - must be between "
519 "%d and %d", start, end);
525 err = (*dev->remove)(n, &err_msg);
532 err_msg = "Device doesn't exist";
536 err_msg = "Device is currently open";
542 mconsole_reply(req, err_msg, err, 0);
545 struct mconsole_output {
546 struct list_head list;
547 struct mc_request *req;
550 static DEFINE_SPINLOCK(client_lock);
551 static LIST_HEAD(clients);
552 static char console_buf[MCONSOLE_MAX_DATA];
554 static void console_write(struct console *console, const char *string,
557 struct list_head *ele;
560 if (list_empty(&clients))
564 n = min((size_t) len, ARRAY_SIZE(console_buf));
565 strncpy(console_buf, string, n);
569 list_for_each(ele, &clients) {
570 struct mconsole_output *entry;
572 entry = list_entry(ele, struct mconsole_output, list);
573 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
578 static struct console mc_console = { .name = "mc",
579 .write = console_write,
580 .flags = CON_ENABLED,
583 static int mc_add_console(void)
585 register_console(&mc_console);
589 late_initcall(mc_add_console);
591 static void with_console(struct mc_request *req, void (*proc)(void *),
594 struct mconsole_output entry;
598 spin_lock_irqsave(&client_lock, flags);
599 list_add(&entry.list, &clients);
600 spin_unlock_irqrestore(&client_lock, flags);
604 mconsole_reply_len(req, "", 0, 0, 0);
606 spin_lock_irqsave(&client_lock, flags);
607 list_del(&entry.list);
608 spin_unlock_irqrestore(&client_lock, flags);
611 #ifdef CONFIG_MAGIC_SYSRQ
613 #include <linux/sysrq.h>
615 static void sysrq_proc(void *arg)
621 void mconsole_sysrq(struct mc_request *req)
623 char *ptr = req->request.data;
625 ptr += strlen("sysrq");
626 ptr = skip_spaces(ptr);
629 * With 'b', the system will shut down without a chance to reply,
630 * so in this case, we reply first.
633 mconsole_reply(req, "", 0, 0);
635 with_console(req, sysrq_proc, ptr);
638 void mconsole_sysrq(struct mc_request *req)
640 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
644 static void stack_proc(void *arg)
646 struct task_struct *task = arg;
648 show_stack(task, NULL);
652 * Mconsole stack trace
653 * Added by Allan Graves, Jeff Dike
654 * Dumps a stacks registers to the linux console.
657 void mconsole_stack(struct mc_request *req)
659 char *ptr = req->request.data;
660 int pid_requested= -1;
661 struct task_struct *to = NULL;
665 * 1) Send showregs output to mconsole.
666 * 2) Add a way to stack dump all pids.
669 ptr += strlen("stack");
670 ptr = skip_spaces(ptr);
673 * Should really check for multiple pids or reject bad args here
675 /* What do the arguments in mconsole_reply mean? */
676 if (sscanf(ptr, "%d", &pid_requested) == 0) {
677 mconsole_reply(req, "Please specify a pid", 1, 0);
681 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
682 if ((to == NULL) || (pid_requested == 0)) {
683 mconsole_reply(req, "Couldn't find that pid", 1, 0);
686 with_console(req, stack_proc, to);
690 * Changed by mconsole_setup, which is __setup, and called before SMP is
693 static char *notify_socket = NULL;
695 static int __init mconsole_init(void)
697 /* long to avoid size mismatch warnings from gcc */
700 char file[UNIX_PATH_MAX];
702 if (umid_file_name("mconsole", file, sizeof(file)))
704 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
706 sock = os_create_unix_socket(file, sizeof(file), 1);
708 printk(KERN_ERR "Failed to initialize management console\n");
711 if (os_set_fd_block(sock, 0))
714 register_reboot_notifier(&reboot_notifier);
716 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
717 IRQF_SHARED, "mconsole", (void *)sock);
719 printk(KERN_ERR "Failed to get IRQ for management console\n");
723 if (notify_socket != NULL) {
724 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
725 if (notify_socket != NULL)
726 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
727 mconsole_socket_name,
728 strlen(mconsole_socket_name) + 1);
729 else printk(KERN_ERR "mconsole_setup failed to strdup "
733 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
734 MCONSOLE_VERSION, mconsole_socket_name);
742 __initcall(mconsole_init);
744 static ssize_t mconsole_proc_write(struct file *file,
745 const char __user *buffer, size_t count, loff_t *pos)
749 buf = memdup_user_nul(buffer, count);
753 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
758 static const struct file_operations mconsole_proc_fops = {
759 .owner = THIS_MODULE,
760 .write = mconsole_proc_write,
761 .llseek = noop_llseek,
764 static int create_proc_mconsole(void)
766 struct proc_dir_entry *ent;
768 if (notify_socket == NULL)
771 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
773 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
779 static DEFINE_SPINLOCK(notify_spinlock);
781 void lock_notify(void)
783 spin_lock(¬ify_spinlock);
786 void unlock_notify(void)
788 spin_unlock(¬ify_spinlock);
791 __initcall(create_proc_mconsole);
793 #define NOTIFY "notify:"
795 static int mconsole_setup(char *str)
797 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
798 str += strlen(NOTIFY);
801 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
805 __setup("mconsole=", mconsole_setup);
807 __uml_help(mconsole_setup,
808 "mconsole=notify:<socket>\n"
809 " Requests that the mconsole driver send a message to the named Unix\n"
810 " socket containing the name of the mconsole socket. This also serves\n"
811 " to notify outside processes when UML has booted far enough to respond\n"
812 " to mconsole requests.\n\n"
815 static int notify_panic(struct notifier_block *self, unsigned long unused1,
820 if (notify_socket == NULL)
823 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
824 strlen(message) + 1);
828 static struct notifier_block panic_exit_notifier = {
829 .notifier_call = notify_panic,
834 static int add_notifier(void)
836 atomic_notifier_chain_register(&panic_notifier_list,
837 &panic_exit_notifier);
841 __initcall(add_notifier);
843 char *mconsole_notify_socket(void)
845 return notify_socket;
848 EXPORT_SYMBOL(mconsole_notify_socket);