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>
25 #include <linux/mount.h>
26 #include <linux/file.h>
27 #include <asm/uaccess.h>
28 #include <asm/switch_to.h>
33 #include <kern_util.h>
35 #include "mconsole_kern.h"
38 static int do_unlink_socket(struct notifier_block *notifier,
39 unsigned long what, void *data)
41 return mconsole_unlink_socket();
45 static struct notifier_block reboot_notifier = {
46 .notifier_call = do_unlink_socket,
50 /* Safe without explicit locking for now. Tasklets provide their own
51 * locking, and the interrupt handler is safe because it can't interrupt
52 * itself and it can only happen on CPU 0.
55 static LIST_HEAD(mc_requests);
57 static void mc_work_proc(struct work_struct *unused)
59 struct mconsole_entry *req;
62 while (!list_empty(&mc_requests)) {
63 local_irq_save(flags);
64 req = list_entry(mc_requests.next, struct mconsole_entry, list);
66 local_irq_restore(flags);
67 req->request.cmd->handler(&req->request);
72 static DECLARE_WORK(mconsole_work, mc_work_proc);
74 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
76 /* long to avoid size mismatch warnings from gcc */
78 struct mconsole_entry *new;
79 static struct mc_request req; /* that's OK */
82 while (mconsole_get_request(fd, &req)) {
83 if (req.cmd->context == MCONSOLE_INTR)
84 (*req.cmd->handler)(&req);
86 new = kmalloc(sizeof(*new), GFP_NOWAIT);
88 mconsole_reply(&req, "Out of memory", 1, 0);
91 new->request.regs = get_irq_regs()->regs;
92 list_add(&new->list, &mc_requests);
96 if (!list_empty(&mc_requests))
97 schedule_work(&mconsole_work);
98 reactivate_fd(fd, MCONSOLE_IRQ);
102 void mconsole_version(struct mc_request *req)
106 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
107 utsname()->nodename, utsname()->release, utsname()->version,
109 mconsole_reply(req, version, 0, 0);
112 void mconsole_log(struct mc_request *req)
115 char *ptr = req->request.data;
117 ptr += strlen("log ");
119 len = req->len - (ptr - req->request.data);
120 printk(KERN_WARNING "%.*s", len, ptr);
121 mconsole_reply(req, "", 0, 0);
124 void mconsole_proc(struct mc_request *req)
126 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
131 char *ptr = req->request.data;
133 ptr += strlen("proc");
134 ptr = skip_spaces(ptr);
136 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY);
138 mconsole_reply(req, "Failed to open file", 1, 0);
139 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
143 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
145 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
150 loff_t pos = file->f_pos;
151 mm_segment_t old_fs = get_fs();
153 len = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
157 mconsole_reply(req, "Read of file failed", 1, 0);
160 /* Begin the file content on his own line. */
162 mconsole_reply(req, "\n", 0, 1);
166 mconsole_reply(req, buf, 0, (len > 0));
175 #define UML_MCONSOLE_HELPTEXT \
177 version - Get kernel version \n\
178 help - Print this message \n\
180 reboot - Reboot UML \n\
181 config <dev>=<config> - Add a new device to UML; \n\
182 same syntax as command line \n\
183 config <dev> - Query the configuration of a device \n\
184 remove <dev> - Remove a device from UML \n\
185 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
186 cad - invoke the Ctrl-Alt-Del handler \n\
187 stop - pause the UML; it will do nothing until it receives a 'go' \n\
188 go - continue the UML after a 'stop' \n\
189 log <string> - make UML enter <string> into the kernel log\n\
190 proc <file> - returns the contents of the UML's /proc/<file>\n\
191 stack <pid> - returns the stack of the specified pid\n\
194 void mconsole_help(struct mc_request *req)
196 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
199 void mconsole_halt(struct mc_request *req)
201 mconsole_reply(req, "", 0, 0);
205 void mconsole_reboot(struct mc_request *req)
207 mconsole_reply(req, "", 0, 0);
208 machine_restart(NULL);
211 void mconsole_cad(struct mc_request *req)
213 mconsole_reply(req, "", 0, 0);
217 void mconsole_go(struct mc_request *req)
219 mconsole_reply(req, "Not stopped", 1, 0);
222 void mconsole_stop(struct mc_request *req)
224 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
225 os_set_fd_block(req->originating_fd, 1);
226 mconsole_reply(req, "stopped", 0, 0);
228 if (!mconsole_get_request(req->originating_fd, req))
230 if (req->cmd->handler == mconsole_go)
232 if (req->cmd->handler == mconsole_stop) {
233 mconsole_reply(req, "Already stopped", 1, 0);
236 if (req->cmd->handler == mconsole_sysrq) {
237 struct pt_regs *old_regs;
238 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
240 set_irq_regs(old_regs);
243 (*req->cmd->handler)(req);
245 os_set_fd_block(req->originating_fd, 0);
246 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
247 mconsole_reply(req, "", 0, 0);
250 static DEFINE_SPINLOCK(mc_devices_lock);
251 static LIST_HEAD(mconsole_devices);
253 void mconsole_register_dev(struct mc_device *new)
255 spin_lock(&mc_devices_lock);
256 BUG_ON(!list_empty(&new->list));
257 list_add(&new->list, &mconsole_devices);
258 spin_unlock(&mc_devices_lock);
261 static struct mc_device *mconsole_find_dev(char *name)
263 struct list_head *ele;
264 struct mc_device *dev;
266 list_for_each(ele, &mconsole_devices) {
267 dev = list_entry(ele, struct mc_device, list);
268 if (!strncmp(name, dev->name, strlen(dev->name)))
274 #define UNPLUGGED_PER_PAGE \
275 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
277 struct unplugged_pages {
278 struct list_head list;
279 void *pages[UNPLUGGED_PER_PAGE];
282 static DEFINE_MUTEX(plug_mem_mutex);
283 static unsigned long long unplugged_pages_count = 0;
284 static LIST_HEAD(unplugged_pages);
285 static int unplug_index = UNPLUGGED_PER_PAGE;
287 static int mem_config(char *str, char **error_out)
289 unsigned long long diff;
290 int err = -EINVAL, i, add;
294 *error_out = "Expected '=' after 'mem'";
301 else if (str[0] == '+') {
305 *error_out = "Expected increment to start with '-' or '+'";
310 diff = memparse(str, &ret);
312 *error_out = "Failed to parse memory increment";
318 mutex_lock(&plug_mem_mutex);
319 for (i = 0; i < diff; i++) {
320 struct unplugged_pages *unplugged;
324 if (list_empty(&unplugged_pages))
327 unplugged = list_entry(unplugged_pages.next,
328 struct unplugged_pages, list);
329 if (unplug_index > 0)
330 addr = unplugged->pages[--unplug_index];
332 list_del(&unplugged->list);
334 unplug_index = UNPLUGGED_PER_PAGE;
337 free_page((unsigned long) addr);
338 unplugged_pages_count--;
343 page = alloc_page(GFP_ATOMIC);
347 unplugged = page_address(page);
348 if (unplug_index == UNPLUGGED_PER_PAGE) {
349 list_add(&unplugged->list, &unplugged_pages);
353 struct list_head *entry = unplugged_pages.next;
356 unplugged = list_entry(entry,
357 struct unplugged_pages,
359 err = os_drop_memory(addr, PAGE_SIZE);
361 printk(KERN_ERR "Failed to release "
362 "memory - errno = %d\n", err);
363 *error_out = "Failed to release memory";
366 unplugged->pages[unplug_index++] = addr;
369 unplugged_pages_count++;
375 mutex_unlock(&plug_mem_mutex);
380 static int mem_get_config(char *name, char *str, int size, char **error_out)
382 char buf[sizeof("18446744073709551615")];
385 sprintf(buf, "%ld", uml_physmem);
386 CONFIG_CHUNK(str, size, len, buf, 1);
391 static int mem_id(char **str, int *start_out, int *end_out)
399 static int mem_remove(int n, char **error_out)
401 *error_out = "Memory doesn't support the remove operation";
405 static struct mc_device mem_mc = {
406 .list = LIST_HEAD_INIT(mem_mc.list),
408 .config = mem_config,
409 .get_config = mem_get_config,
411 .remove = mem_remove,
414 static int __init mem_mc_init(void)
416 if (can_drop_memory())
417 mconsole_register_dev(&mem_mc);
418 else printk(KERN_ERR "Can't release memory to the host - memory "
419 "hotplug won't be supported\n");
423 __initcall(mem_mc_init);
425 #define CONFIG_BUF_SIZE 64
427 static void mconsole_get_config(int (*get_config)(char *, char *, int,
429 struct mc_request *req, char *name)
431 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
434 if (get_config == NULL) {
435 mconsole_reply(req, "No get_config routine defined", 1, 0);
440 size = ARRAY_SIZE(default_buf);
444 n = (*get_config)(name, buf, size, &error);
446 mconsole_reply(req, error, 1, 0);
451 mconsole_reply(req, buf, 0, 0);
455 if (buf != default_buf)
459 buf = kmalloc(size, GFP_KERNEL);
461 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
466 if (buf != default_buf)
470 void mconsole_config(struct mc_request *req)
472 struct mc_device *dev;
473 char *ptr = req->request.data, *name, *error_string = "";
476 ptr += strlen("config");
477 ptr = skip_spaces(ptr);
478 dev = mconsole_find_dev(ptr);
480 mconsole_reply(req, "Bad configuration option", 1, 0);
484 name = &ptr[strlen(dev->name)];
486 while ((*ptr != '=') && (*ptr != '\0'))
490 err = (*dev->config)(name, &error_string);
491 mconsole_reply(req, error_string, err, 0);
493 else mconsole_get_config(dev->get_config, req, name);
496 void mconsole_remove(struct mc_request *req)
498 struct mc_device *dev;
499 char *ptr = req->request.data, *err_msg = "";
501 int err, start, end, n;
503 ptr += strlen("remove");
504 ptr = skip_spaces(ptr);
505 dev = mconsole_find_dev(ptr);
507 mconsole_reply(req, "Bad remove option", 1, 0);
511 ptr = &ptr[strlen(dev->name)];
514 n = (*dev->id)(&ptr, &start, &end);
516 err_msg = "Couldn't parse device number";
519 else if ((n < start) || (n > end)) {
520 sprintf(error, "Invalid device number - must be between "
521 "%d and %d", start, end);
527 err = (*dev->remove)(n, &err_msg);
534 err_msg = "Device doesn't exist";
538 err_msg = "Device is currently open";
544 mconsole_reply(req, err_msg, err, 0);
547 struct mconsole_output {
548 struct list_head list;
549 struct mc_request *req;
552 static DEFINE_SPINLOCK(client_lock);
553 static LIST_HEAD(clients);
554 static char console_buf[MCONSOLE_MAX_DATA];
556 static void console_write(struct console *console, const char *string,
559 struct list_head *ele;
562 if (list_empty(&clients))
566 n = min((size_t) len, ARRAY_SIZE(console_buf));
567 strncpy(console_buf, string, n);
571 list_for_each(ele, &clients) {
572 struct mconsole_output *entry;
574 entry = list_entry(ele, struct mconsole_output, list);
575 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
580 static struct console mc_console = { .name = "mc",
581 .write = console_write,
582 .flags = CON_ENABLED,
585 static int mc_add_console(void)
587 register_console(&mc_console);
591 late_initcall(mc_add_console);
593 static void with_console(struct mc_request *req, void (*proc)(void *),
596 struct mconsole_output entry;
600 spin_lock_irqsave(&client_lock, flags);
601 list_add(&entry.list, &clients);
602 spin_unlock_irqrestore(&client_lock, flags);
606 mconsole_reply_len(req, "", 0, 0, 0);
608 spin_lock_irqsave(&client_lock, flags);
609 list_del(&entry.list);
610 spin_unlock_irqrestore(&client_lock, flags);
613 #ifdef CONFIG_MAGIC_SYSRQ
615 #include <linux/sysrq.h>
617 static void sysrq_proc(void *arg)
623 void mconsole_sysrq(struct mc_request *req)
625 char *ptr = req->request.data;
627 ptr += strlen("sysrq");
628 ptr = skip_spaces(ptr);
631 * With 'b', the system will shut down without a chance to reply,
632 * so in this case, we reply first.
635 mconsole_reply(req, "", 0, 0);
637 with_console(req, sysrq_proc, ptr);
640 void mconsole_sysrq(struct mc_request *req)
642 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
646 static void stack_proc(void *arg)
648 struct task_struct *task = arg;
650 show_stack(task, NULL);
654 * Mconsole stack trace
655 * Added by Allan Graves, Jeff Dike
656 * Dumps a stacks registers to the linux console.
659 void mconsole_stack(struct mc_request *req)
661 char *ptr = req->request.data;
662 int pid_requested= -1;
663 struct task_struct *to = NULL;
667 * 1) Send showregs output to mconsole.
668 * 2) Add a way to stack dump all pids.
671 ptr += strlen("stack");
672 ptr = skip_spaces(ptr);
675 * Should really check for multiple pids or reject bad args here
677 /* What do the arguments in mconsole_reply mean? */
678 if (sscanf(ptr, "%d", &pid_requested) == 0) {
679 mconsole_reply(req, "Please specify a pid", 1, 0);
683 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
684 if ((to == NULL) || (pid_requested == 0)) {
685 mconsole_reply(req, "Couldn't find that pid", 1, 0);
688 with_console(req, stack_proc, to);
692 * Changed by mconsole_setup, which is __setup, and called before SMP is
695 static char *notify_socket = NULL;
697 static int __init mconsole_init(void)
699 /* long to avoid size mismatch warnings from gcc */
702 char file[UNIX_PATH_MAX];
704 if (umid_file_name("mconsole", file, sizeof(file)))
706 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
708 sock = os_create_unix_socket(file, sizeof(file), 1);
710 printk(KERN_ERR "Failed to initialize management console\n");
713 if (os_set_fd_block(sock, 0))
716 register_reboot_notifier(&reboot_notifier);
718 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
719 IRQF_SHARED, "mconsole", (void *)sock);
721 printk(KERN_ERR "Failed to get IRQ for management console\n");
725 if (notify_socket != NULL) {
726 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
727 if (notify_socket != NULL)
728 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
729 mconsole_socket_name,
730 strlen(mconsole_socket_name) + 1);
731 else printk(KERN_ERR "mconsole_setup failed to strdup "
735 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
736 MCONSOLE_VERSION, mconsole_socket_name);
744 __initcall(mconsole_init);
746 static ssize_t mconsole_proc_write(struct file *file,
747 const char __user *buffer, size_t count, loff_t *pos)
751 buf = kmalloc(count + 1, GFP_KERNEL);
755 if (copy_from_user(buf, buffer, count)) {
762 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
768 static const struct file_operations mconsole_proc_fops = {
769 .owner = THIS_MODULE,
770 .write = mconsole_proc_write,
771 .llseek = noop_llseek,
774 static int create_proc_mconsole(void)
776 struct proc_dir_entry *ent;
778 if (notify_socket == NULL)
781 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
783 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
789 static DEFINE_SPINLOCK(notify_spinlock);
791 void lock_notify(void)
793 spin_lock(¬ify_spinlock);
796 void unlock_notify(void)
798 spin_unlock(¬ify_spinlock);
801 __initcall(create_proc_mconsole);
803 #define NOTIFY "notify:"
805 static int mconsole_setup(char *str)
807 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
808 str += strlen(NOTIFY);
811 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
815 __setup("mconsole=", mconsole_setup);
817 __uml_help(mconsole_setup,
818 "mconsole=notify:<socket>\n"
819 " Requests that the mconsole driver send a message to the named Unix\n"
820 " socket containing the name of the mconsole socket. This also serves\n"
821 " to notify outside processes when UML has booted far enough to respond\n"
822 " to mconsole requests.\n\n"
825 static int notify_panic(struct notifier_block *self, unsigned long unused1,
830 if (notify_socket == NULL)
833 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
834 strlen(message) + 1);
838 static struct notifier_block panic_exit_notifier = {
839 .notifier_call = notify_panic,
844 static int add_notifier(void)
846 atomic_notifier_chain_register(&panic_notifier_list,
847 &panic_exit_notifier);
851 __initcall(add_notifier);
853 char *mconsole_notify_socket(void)
855 return notify_socket;
858 EXPORT_SYMBOL(mconsole_notify_socket);