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 file_system_type *proc;
129 struct super_block *super;
132 char *ptr = req->request.data, *buf;
134 ptr += strlen("proc");
135 ptr = skip_spaces(ptr);
137 proc = get_fs_type("proc");
139 mconsole_reply(req, "procfs not registered", 1, 0);
143 super = (*proc->get_sb)(proc, 0, NULL, NULL);
144 put_filesystem(proc);
146 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
149 up_write(&super->s_umount);
151 nd.path.dentry = super->s_root;
153 nd.flags = O_RDONLY + 1;
154 nd.last_type = LAST_ROOT;
156 /* START: it was experienced that the stability problems are closed
157 * if commenting out these two calls + the below read cycle. To
158 * make UML crash again, it was enough to readd either one.*/
159 err = link_path_walk(ptr, &nd);
161 mconsole_reply(req, "Failed to look up file", 1, 0);
165 file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
168 mconsole_reply(req, "Failed to open file", 1, 0);
173 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
175 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
179 if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
181 n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
185 mconsole_reply(req, buf, 0, (n > 0));
188 mconsole_reply(req, "Read of file failed",
194 else mconsole_reply(req, "", 0, 0);
201 deactivate_super(super);
206 void mconsole_proc(struct mc_request *req)
213 char *ptr = req->request.data;
215 ptr += strlen("proc");
216 ptr = skip_spaces(ptr);
217 snprintf(path, sizeof(path), "/proc/%s", ptr);
219 fd = sys_open(path, 0, 0);
221 mconsole_reply(req, "Failed to open file", 1, 0);
222 printk(KERN_ERR "open %s: %d\n",path,fd);
226 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
228 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
233 len = sys_read(fd, buf, PAGE_SIZE-1);
235 mconsole_reply(req, "Read of file failed", 1, 0);
238 /* Begin the file content on his own line. */
240 mconsole_reply(req, "\n", 0, 1);
243 if (len == PAGE_SIZE-1) {
245 mconsole_reply(req, buf, 0, 1);
248 mconsole_reply(req, buf, 0, 0);
261 #define UML_MCONSOLE_HELPTEXT \
263 version - Get kernel version \n\
264 help - Print this message \n\
266 reboot - Reboot UML \n\
267 config <dev>=<config> - Add a new device to UML; \n\
268 same syntax as command line \n\
269 config <dev> - Query the configuration of a device \n\
270 remove <dev> - Remove a device from UML \n\
271 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
272 cad - invoke the Ctrl-Alt-Del handler \n\
273 stop - pause the UML; it will do nothing until it receives a 'go' \n\
274 go - continue the UML after a 'stop' \n\
275 log <string> - make UML enter <string> into the kernel log\n\
276 proc <file> - returns the contents of the UML's /proc/<file>\n\
277 stack <pid> - returns the stack of the specified pid\n\
280 void mconsole_help(struct mc_request *req)
282 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
285 void mconsole_halt(struct mc_request *req)
287 mconsole_reply(req, "", 0, 0);
291 void mconsole_reboot(struct mc_request *req)
293 mconsole_reply(req, "", 0, 0);
294 machine_restart(NULL);
297 void mconsole_cad(struct mc_request *req)
299 mconsole_reply(req, "", 0, 0);
303 void mconsole_go(struct mc_request *req)
305 mconsole_reply(req, "Not stopped", 1, 0);
308 void mconsole_stop(struct mc_request *req)
310 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
311 os_set_fd_block(req->originating_fd, 1);
312 mconsole_reply(req, "stopped", 0, 0);
314 if (!mconsole_get_request(req->originating_fd, req))
316 if (req->cmd->handler == mconsole_go)
318 if (req->cmd->handler == mconsole_stop) {
319 mconsole_reply(req, "Already stopped", 1, 0);
322 if (req->cmd->handler == mconsole_sysrq) {
323 struct pt_regs *old_regs;
324 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
326 set_irq_regs(old_regs);
329 (*req->cmd->handler)(req);
331 os_set_fd_block(req->originating_fd, 0);
332 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
333 mconsole_reply(req, "", 0, 0);
336 static DEFINE_SPINLOCK(mc_devices_lock);
337 static LIST_HEAD(mconsole_devices);
339 void mconsole_register_dev(struct mc_device *new)
341 spin_lock(&mc_devices_lock);
342 BUG_ON(!list_empty(&new->list));
343 list_add(&new->list, &mconsole_devices);
344 spin_unlock(&mc_devices_lock);
347 static struct mc_device *mconsole_find_dev(char *name)
349 struct list_head *ele;
350 struct mc_device *dev;
352 list_for_each(ele, &mconsole_devices) {
353 dev = list_entry(ele, struct mc_device, list);
354 if (!strncmp(name, dev->name, strlen(dev->name)))
360 #define UNPLUGGED_PER_PAGE \
361 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
363 struct unplugged_pages {
364 struct list_head list;
365 void *pages[UNPLUGGED_PER_PAGE];
368 static DEFINE_MUTEX(plug_mem_mutex);
369 static unsigned long long unplugged_pages_count = 0;
370 static LIST_HEAD(unplugged_pages);
371 static int unplug_index = UNPLUGGED_PER_PAGE;
373 static int mem_config(char *str, char **error_out)
375 unsigned long long diff;
376 int err = -EINVAL, i, add;
380 *error_out = "Expected '=' after 'mem'";
387 else if (str[0] == '+') {
391 *error_out = "Expected increment to start with '-' or '+'";
396 diff = memparse(str, &ret);
398 *error_out = "Failed to parse memory increment";
404 mutex_lock(&plug_mem_mutex);
405 for (i = 0; i < diff; i++) {
406 struct unplugged_pages *unplugged;
410 if (list_empty(&unplugged_pages))
413 unplugged = list_entry(unplugged_pages.next,
414 struct unplugged_pages, list);
415 if (unplug_index > 0)
416 addr = unplugged->pages[--unplug_index];
418 list_del(&unplugged->list);
420 unplug_index = UNPLUGGED_PER_PAGE;
423 free_page((unsigned long) addr);
424 unplugged_pages_count--;
429 page = alloc_page(GFP_ATOMIC);
433 unplugged = page_address(page);
434 if (unplug_index == UNPLUGGED_PER_PAGE) {
435 list_add(&unplugged->list, &unplugged_pages);
439 struct list_head *entry = unplugged_pages.next;
442 unplugged = list_entry(entry,
443 struct unplugged_pages,
445 err = os_drop_memory(addr, PAGE_SIZE);
447 printk(KERN_ERR "Failed to release "
448 "memory - errno = %d\n", err);
449 *error_out = "Failed to release memory";
452 unplugged->pages[unplug_index++] = addr;
455 unplugged_pages_count++;
461 mutex_unlock(&plug_mem_mutex);
466 static int mem_get_config(char *name, char *str, int size, char **error_out)
468 char buf[sizeof("18446744073709551615")];
471 sprintf(buf, "%ld", uml_physmem);
472 CONFIG_CHUNK(str, size, len, buf, 1);
477 static int mem_id(char **str, int *start_out, int *end_out)
485 static int mem_remove(int n, char **error_out)
487 *error_out = "Memory doesn't support the remove operation";
491 static struct mc_device mem_mc = {
492 .list = LIST_HEAD_INIT(mem_mc.list),
494 .config = mem_config,
495 .get_config = mem_get_config,
497 .remove = mem_remove,
500 static int __init mem_mc_init(void)
502 if (can_drop_memory())
503 mconsole_register_dev(&mem_mc);
504 else printk(KERN_ERR "Can't release memory to the host - memory "
505 "hotplug won't be supported\n");
509 __initcall(mem_mc_init);
511 #define CONFIG_BUF_SIZE 64
513 static void mconsole_get_config(int (*get_config)(char *, char *, int,
515 struct mc_request *req, char *name)
517 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
520 if (get_config == NULL) {
521 mconsole_reply(req, "No get_config routine defined", 1, 0);
526 size = ARRAY_SIZE(default_buf);
530 n = (*get_config)(name, buf, size, &error);
532 mconsole_reply(req, error, 1, 0);
537 mconsole_reply(req, buf, 0, 0);
541 if (buf != default_buf)
545 buf = kmalloc(size, GFP_KERNEL);
547 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
552 if (buf != default_buf)
556 void mconsole_config(struct mc_request *req)
558 struct mc_device *dev;
559 char *ptr = req->request.data, *name, *error_string = "";
562 ptr += strlen("config");
563 ptr = skip_spaces(ptr);
564 dev = mconsole_find_dev(ptr);
566 mconsole_reply(req, "Bad configuration option", 1, 0);
570 name = &ptr[strlen(dev->name)];
572 while ((*ptr != '=') && (*ptr != '\0'))
576 err = (*dev->config)(name, &error_string);
577 mconsole_reply(req, error_string, err, 0);
579 else mconsole_get_config(dev->get_config, req, name);
582 void mconsole_remove(struct mc_request *req)
584 struct mc_device *dev;
585 char *ptr = req->request.data, *err_msg = "";
587 int err, start, end, n;
589 ptr += strlen("remove");
590 ptr = skip_spaces(ptr);
591 dev = mconsole_find_dev(ptr);
593 mconsole_reply(req, "Bad remove option", 1, 0);
597 ptr = &ptr[strlen(dev->name)];
600 n = (*dev->id)(&ptr, &start, &end);
602 err_msg = "Couldn't parse device number";
605 else if ((n < start) || (n > end)) {
606 sprintf(error, "Invalid device number - must be between "
607 "%d and %d", start, end);
613 err = (*dev->remove)(n, &err_msg);
620 err_msg = "Device doesn't exist";
624 err_msg = "Device is currently open";
630 mconsole_reply(req, err_msg, err, 0);
633 struct mconsole_output {
634 struct list_head list;
635 struct mc_request *req;
638 static DEFINE_SPINLOCK(client_lock);
639 static LIST_HEAD(clients);
640 static char console_buf[MCONSOLE_MAX_DATA];
642 static void console_write(struct console *console, const char *string,
645 struct list_head *ele;
648 if (list_empty(&clients))
652 n = min((size_t) len, ARRAY_SIZE(console_buf));
653 strncpy(console_buf, string, n);
657 list_for_each(ele, &clients) {
658 struct mconsole_output *entry;
660 entry = list_entry(ele, struct mconsole_output, list);
661 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
666 static struct console mc_console = { .name = "mc",
667 .write = console_write,
668 .flags = CON_ENABLED,
671 static int mc_add_console(void)
673 register_console(&mc_console);
677 late_initcall(mc_add_console);
679 static void with_console(struct mc_request *req, void (*proc)(void *),
682 struct mconsole_output entry;
686 spin_lock_irqsave(&client_lock, flags);
687 list_add(&entry.list, &clients);
688 spin_unlock_irqrestore(&client_lock, flags);
692 mconsole_reply_len(req, "", 0, 0, 0);
694 spin_lock_irqsave(&client_lock, flags);
695 list_del(&entry.list);
696 spin_unlock_irqrestore(&client_lock, flags);
699 #ifdef CONFIG_MAGIC_SYSRQ
701 #include <linux/sysrq.h>
703 static void sysrq_proc(void *arg)
706 handle_sysrq(*op, NULL);
709 void mconsole_sysrq(struct mc_request *req)
711 char *ptr = req->request.data;
713 ptr += strlen("sysrq");
714 ptr = skip_spaces(ptr);
717 * With 'b', the system will shut down without a chance to reply,
718 * so in this case, we reply first.
721 mconsole_reply(req, "", 0, 0);
723 with_console(req, sysrq_proc, ptr);
726 void mconsole_sysrq(struct mc_request *req)
728 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
732 static void stack_proc(void *arg)
734 struct task_struct *from = current, *to = arg;
736 to->thread.saved_task = from;
737 switch_to(from, to, from);
741 * Mconsole stack trace
742 * Added by Allan Graves, Jeff Dike
743 * Dumps a stacks registers to the linux console.
746 void mconsole_stack(struct mc_request *req)
748 char *ptr = req->request.data;
749 int pid_requested= -1;
750 struct task_struct *to = NULL;
754 * 1) Send showregs output to mconsole.
755 * 2) Add a way to stack dump all pids.
758 ptr += strlen("stack");
759 ptr = skip_spaces(ptr);
762 * Should really check for multiple pids or reject bad args here
764 /* What do the arguments in mconsole_reply mean? */
765 if (sscanf(ptr, "%d", &pid_requested) == 0) {
766 mconsole_reply(req, "Please specify a pid", 1, 0);
770 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
771 if ((to == NULL) || (pid_requested == 0)) {
772 mconsole_reply(req, "Couldn't find that pid", 1, 0);
775 with_console(req, stack_proc, to);
779 * Changed by mconsole_setup, which is __setup, and called before SMP is
782 static char *notify_socket = NULL;
784 static int __init mconsole_init(void)
786 /* long to avoid size mismatch warnings from gcc */
789 char file[UNIX_PATH_MAX];
791 if (umid_file_name("mconsole", file, sizeof(file)))
793 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
795 sock = os_create_unix_socket(file, sizeof(file), 1);
797 printk(KERN_ERR "Failed to initialize management console\n");
800 if (os_set_fd_block(sock, 0))
803 register_reboot_notifier(&reboot_notifier);
805 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
806 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
807 "mconsole", (void *)sock);
809 printk(KERN_ERR "Failed to get IRQ for management console\n");
813 if (notify_socket != NULL) {
814 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
815 if (notify_socket != NULL)
816 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
817 mconsole_socket_name,
818 strlen(mconsole_socket_name) + 1);
819 else printk(KERN_ERR "mconsole_setup failed to strdup "
823 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
824 MCONSOLE_VERSION, mconsole_socket_name);
832 __initcall(mconsole_init);
834 static ssize_t mconsole_proc_write(struct file *file,
835 const char __user *buffer, size_t count, loff_t *pos)
839 buf = kmalloc(count + 1, GFP_KERNEL);
843 if (copy_from_user(buf, buffer, count)) {
850 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
856 static const struct file_operations mconsole_proc_fops = {
857 .owner = THIS_MODULE,
858 .write = mconsole_proc_write,
861 static int create_proc_mconsole(void)
863 struct proc_dir_entry *ent;
865 if (notify_socket == NULL)
868 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
870 printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
877 static DEFINE_SPINLOCK(notify_spinlock);
879 void lock_notify(void)
881 spin_lock(¬ify_spinlock);
884 void unlock_notify(void)
886 spin_unlock(¬ify_spinlock);
889 __initcall(create_proc_mconsole);
891 #define NOTIFY "notify:"
893 static int mconsole_setup(char *str)
895 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
896 str += strlen(NOTIFY);
899 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
903 __setup("mconsole=", mconsole_setup);
905 __uml_help(mconsole_setup,
906 "mconsole=notify:<socket>\n"
907 " Requests that the mconsole driver send a message to the named Unix\n"
908 " socket containing the name of the mconsole socket. This also serves\n"
909 " to notify outside processes when UML has booted far enough to respond\n"
910 " to mconsole requests.\n\n"
913 static int notify_panic(struct notifier_block *self, unsigned long unused1,
918 if (notify_socket == NULL)
921 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
922 strlen(message) + 1);
926 static struct notifier_block panic_exit_notifier = {
927 .notifier_call = notify_panic,
932 static int add_notifier(void)
934 atomic_notifier_chain_register(&panic_notifier_list,
935 &panic_exit_notifier);
939 __initcall(add_notifier);
941 char *mconsole_notify_socket(void)
943 return notify_socket;
946 EXPORT_SYMBOL(mconsole_notify_socket);