2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3 * Copyright (C) 2001 - 2007 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/interrupt.h"
10 #include "linux/list.h"
12 #include "linux/module.h"
13 #include "linux/notifier.h"
14 #include "linux/reboot.h"
15 #include "linux/proc_fs.h"
16 #include "linux/slab.h"
17 #include "linux/syscalls.h"
18 #include "linux/utsname.h"
19 #include "linux/workqueue.h"
20 #include "linux/mutex.h"
21 #include "asm/uaccess.h"
25 #include "kern_util.h"
27 #include "mconsole_kern.h"
30 static int do_unlink_socket(struct notifier_block *notifier,
31 unsigned long what, void *data)
33 return mconsole_unlink_socket();
37 static struct notifier_block reboot_notifier = {
38 .notifier_call = do_unlink_socket,
42 /* Safe without explicit locking for now. Tasklets provide their own
43 * locking, and the interrupt handler is safe because it can't interrupt
44 * itself and it can only happen on CPU 0.
47 static LIST_HEAD(mc_requests);
49 static void mc_work_proc(struct work_struct *unused)
51 struct mconsole_entry *req;
54 while (!list_empty(&mc_requests)) {
55 local_irq_save(flags);
56 req = list_entry(mc_requests.next, struct mconsole_entry, list);
58 local_irq_restore(flags);
59 req->request.cmd->handler(&req->request);
64 static DECLARE_WORK(mconsole_work, mc_work_proc);
66 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
68 /* long to avoid size mismatch warnings from gcc */
70 struct mconsole_entry *new;
71 static struct mc_request req; /* that's OK */
74 while (mconsole_get_request(fd, &req)) {
75 if (req.cmd->context == MCONSOLE_INTR)
76 (*req.cmd->handler)(&req);
78 new = kmalloc(sizeof(*new), GFP_NOWAIT);
80 mconsole_reply(&req, "Out of memory", 1, 0);
83 new->request.regs = get_irq_regs()->regs;
84 list_add(&new->list, &mc_requests);
88 if (!list_empty(&mc_requests))
89 schedule_work(&mconsole_work);
90 reactivate_fd(fd, MCONSOLE_IRQ);
94 void mconsole_version(struct mc_request *req)
98 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
99 utsname()->nodename, utsname()->release, utsname()->version,
101 mconsole_reply(req, version, 0, 0);
104 void mconsole_log(struct mc_request *req)
107 char *ptr = req->request.data;
109 ptr += strlen("log ");
111 len = req->len - (ptr - req->request.data);
112 printk(KERN_WARNING "%.*s", len, ptr);
113 mconsole_reply(req, "", 0, 0);
116 /* This is a more convoluted version of mconsole_proc, which has some stability
117 * problems; however, we need it fixed, because it is expected that UML users
118 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
119 * show the real procfs content, not the ones from hppfs.*/
121 void mconsole_proc(struct mc_request *req)
124 struct file_system_type *proc;
125 struct super_block *super;
128 char *ptr = req->request.data, *buf;
130 ptr += strlen("proc");
131 while (isspace(*ptr)) ptr++;
133 proc = get_fs_type("proc");
135 mconsole_reply(req, "procfs not registered", 1, 0);
139 super = (*proc->get_sb)(proc, 0, NULL, NULL);
140 put_filesystem(proc);
142 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
145 up_write(&super->s_umount);
147 nd.dentry = super->s_root;
149 nd.flags = O_RDONLY + 1;
150 nd.last_type = LAST_ROOT;
152 /* START: it was experienced that the stability problems are closed
153 * if commenting out these two calls + the below read cycle. To
154 * make UML crash again, it was enough to readd either one.*/
155 err = link_path_walk(ptr, &nd);
157 mconsole_reply(req, "Failed to look up file", 1, 0);
161 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
163 mconsole_reply(req, "Failed to open file", 1, 0);
168 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
170 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
174 if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
176 n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
180 mconsole_reply(req, buf, 0, (n > 0));
183 mconsole_reply(req, "Read of file failed",
189 else mconsole_reply(req, "", 0, 0);
196 deactivate_super(super);
201 void mconsole_proc(struct mc_request *req)
208 char *ptr = req->request.data;
210 ptr += strlen("proc");
211 while (isspace(*ptr))
213 snprintf(path, sizeof(path), "/proc/%s", ptr);
215 fd = sys_open(path, 0, 0);
217 mconsole_reply(req, "Failed to open file", 1, 0);
218 printk(KERN_ERR "open %s: %d\n",path,fd);
222 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
224 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
229 len = sys_read(fd, buf, PAGE_SIZE-1);
231 mconsole_reply(req, "Read of file failed", 1, 0);
234 /* Begin the file content on his own line. */
236 mconsole_reply(req, "\n", 0, 1);
239 if (len == PAGE_SIZE-1) {
241 mconsole_reply(req, buf, 0, 1);
244 mconsole_reply(req, buf, 0, 0);
257 #define UML_MCONSOLE_HELPTEXT \
259 version - Get kernel version \n\
260 help - Print this message \n\
262 reboot - Reboot UML \n\
263 config <dev>=<config> - Add a new device to UML; \n\
264 same syntax as command line \n\
265 config <dev> - Query the configuration of a device \n\
266 remove <dev> - Remove a device from UML \n\
267 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
268 cad - invoke the Ctrl-Alt-Del handler \n\
269 stop - pause the UML; it will do nothing until it receives a 'go' \n\
270 go - continue the UML after a 'stop' \n\
271 log <string> - make UML enter <string> into the kernel log\n\
272 proc <file> - returns the contents of the UML's /proc/<file>\n\
273 stack <pid> - returns the stack of the specified pid\n\
276 void mconsole_help(struct mc_request *req)
278 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
281 void mconsole_halt(struct mc_request *req)
283 mconsole_reply(req, "", 0, 0);
287 void mconsole_reboot(struct mc_request *req)
289 mconsole_reply(req, "", 0, 0);
290 machine_restart(NULL);
293 void mconsole_cad(struct mc_request *req)
295 mconsole_reply(req, "", 0, 0);
299 void mconsole_go(struct mc_request *req)
301 mconsole_reply(req, "Not stopped", 1, 0);
304 void mconsole_stop(struct mc_request *req)
306 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
307 os_set_fd_block(req->originating_fd, 1);
308 mconsole_reply(req, "stopped", 0, 0);
310 if (!mconsole_get_request(req->originating_fd, req))
312 if (req->cmd->handler == mconsole_go)
314 if (req->cmd->handler == mconsole_stop) {
315 mconsole_reply(req, "Already stopped", 1, 0);
318 if (req->cmd->handler == mconsole_sysrq) {
319 struct pt_regs *old_regs;
320 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
322 set_irq_regs(old_regs);
325 (*req->cmd->handler)(req);
327 os_set_fd_block(req->originating_fd, 0);
328 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
329 mconsole_reply(req, "", 0, 0);
332 static DEFINE_SPINLOCK(mc_devices_lock);
333 static LIST_HEAD(mconsole_devices);
335 void mconsole_register_dev(struct mc_device *new)
337 spin_lock(&mc_devices_lock);
338 BUG_ON(!list_empty(&new->list));
339 list_add(&new->list, &mconsole_devices);
340 spin_unlock(&mc_devices_lock);
343 static struct mc_device *mconsole_find_dev(char *name)
345 struct list_head *ele;
346 struct mc_device *dev;
348 list_for_each(ele, &mconsole_devices) {
349 dev = list_entry(ele, struct mc_device, list);
350 if (!strncmp(name, dev->name, strlen(dev->name)))
356 #define UNPLUGGED_PER_PAGE \
357 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
359 struct unplugged_pages {
360 struct list_head list;
361 void *pages[UNPLUGGED_PER_PAGE];
364 static DEFINE_MUTEX(plug_mem_mutex);
365 static unsigned long long unplugged_pages_count = 0;
366 static LIST_HEAD(unplugged_pages);
367 static int unplug_index = UNPLUGGED_PER_PAGE;
369 static int mem_config(char *str, char **error_out)
371 unsigned long long diff;
372 int err = -EINVAL, i, add;
376 *error_out = "Expected '=' after 'mem'";
383 else if (str[0] == '+') {
387 *error_out = "Expected increment to start with '-' or '+'";
392 diff = memparse(str, &ret);
394 *error_out = "Failed to parse memory increment";
400 mutex_lock(&plug_mem_mutex);
401 for (i = 0; i < diff; i++) {
402 struct unplugged_pages *unplugged;
406 if (list_empty(&unplugged_pages))
409 unplugged = list_entry(unplugged_pages.next,
410 struct unplugged_pages, list);
411 if (unplug_index > 0)
412 addr = unplugged->pages[--unplug_index];
414 list_del(&unplugged->list);
416 unplug_index = UNPLUGGED_PER_PAGE;
419 free_page((unsigned long) addr);
420 unplugged_pages_count--;
425 page = alloc_page(GFP_ATOMIC);
429 unplugged = page_address(page);
430 if (unplug_index == UNPLUGGED_PER_PAGE) {
431 list_add(&unplugged->list, &unplugged_pages);
435 struct list_head *entry = unplugged_pages.next;
438 unplugged = list_entry(entry,
439 struct unplugged_pages,
441 err = os_drop_memory(addr, PAGE_SIZE);
443 printk(KERN_ERR "Failed to release "
444 "memory - errno = %d\n", err);
445 *error_out = "Failed to release memory";
448 unplugged->pages[unplug_index++] = addr;
451 unplugged_pages_count++;
457 mutex_unlock(&plug_mem_mutex);
462 static int mem_get_config(char *name, char *str, int size, char **error_out)
464 char buf[sizeof("18446744073709551615")];
467 sprintf(buf, "%ld", uml_physmem);
468 CONFIG_CHUNK(str, size, len, buf, 1);
473 static int mem_id(char **str, int *start_out, int *end_out)
481 static int mem_remove(int n, char **error_out)
483 *error_out = "Memory doesn't support the remove operation";
487 static struct mc_device mem_mc = {
488 .list = LIST_HEAD_INIT(mem_mc.list),
490 .config = mem_config,
491 .get_config = mem_get_config,
493 .remove = mem_remove,
496 static int __init mem_mc_init(void)
498 if (can_drop_memory())
499 mconsole_register_dev(&mem_mc);
500 else printk(KERN_ERR "Can't release memory to the host - memory "
501 "hotplug won't be supported\n");
505 __initcall(mem_mc_init);
507 #define CONFIG_BUF_SIZE 64
509 static void mconsole_get_config(int (*get_config)(char *, char *, int,
511 struct mc_request *req, char *name)
513 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
516 if (get_config == NULL) {
517 mconsole_reply(req, "No get_config routine defined", 1, 0);
522 size = ARRAY_SIZE(default_buf);
526 n = (*get_config)(name, buf, size, &error);
528 mconsole_reply(req, error, 1, 0);
533 mconsole_reply(req, buf, 0, 0);
537 if (buf != default_buf)
541 buf = kmalloc(size, GFP_KERNEL);
543 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
548 if (buf != default_buf)
552 void mconsole_config(struct mc_request *req)
554 struct mc_device *dev;
555 char *ptr = req->request.data, *name, *error_string = "";
558 ptr += strlen("config");
559 while (isspace(*ptr))
561 dev = mconsole_find_dev(ptr);
563 mconsole_reply(req, "Bad configuration option", 1, 0);
567 name = &ptr[strlen(dev->name)];
569 while ((*ptr != '=') && (*ptr != '\0'))
573 err = (*dev->config)(name, &error_string);
574 mconsole_reply(req, error_string, err, 0);
576 else mconsole_get_config(dev->get_config, req, name);
579 void mconsole_remove(struct mc_request *req)
581 struct mc_device *dev;
582 char *ptr = req->request.data, *err_msg = "";
584 int err, start, end, n;
586 ptr += strlen("remove");
587 while (isspace(*ptr)) ptr++;
588 dev = mconsole_find_dev(ptr);
590 mconsole_reply(req, "Bad remove option", 1, 0);
594 ptr = &ptr[strlen(dev->name)];
597 n = (*dev->id)(&ptr, &start, &end);
599 err_msg = "Couldn't parse device number";
602 else if ((n < start) || (n > end)) {
603 sprintf(error, "Invalid device number - must be between "
604 "%d and %d", start, end);
610 err = (*dev->remove)(n, &err_msg);
617 err_msg = "Device doesn't exist";
621 err_msg = "Device is currently open";
627 mconsole_reply(req, err_msg, err, 0);
630 struct mconsole_output {
631 struct list_head list;
632 struct mc_request *req;
635 static DEFINE_SPINLOCK(client_lock);
636 static LIST_HEAD(clients);
637 static char console_buf[MCONSOLE_MAX_DATA];
639 static void console_write(struct console *console, const char *string,
642 struct list_head *ele;
645 if (list_empty(&clients))
649 n = min((size_t) len, ARRAY_SIZE(console_buf));
650 strncpy(console_buf, string, n);
654 list_for_each(ele, &clients) {
655 struct mconsole_output *entry;
657 entry = list_entry(ele, struct mconsole_output, list);
658 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
663 static struct console mc_console = { .name = "mc",
664 .write = console_write,
665 .flags = CON_ENABLED,
668 static int mc_add_console(void)
670 register_console(&mc_console);
674 late_initcall(mc_add_console);
676 static void with_console(struct mc_request *req, void (*proc)(void *),
679 struct mconsole_output entry;
683 spin_lock_irqsave(&client_lock, flags);
684 list_add(&entry.list, &clients);
685 spin_unlock_irqrestore(&client_lock, flags);
689 mconsole_reply_len(req, "", 0, 0, 0);
691 spin_lock_irqsave(&client_lock, flags);
692 list_del(&entry.list);
693 spin_unlock_irqrestore(&client_lock, flags);
696 #ifdef CONFIG_MAGIC_SYSRQ
698 #include <linux/sysrq.h>
700 static void sysrq_proc(void *arg)
703 handle_sysrq(*op, NULL);
706 void mconsole_sysrq(struct mc_request *req)
708 char *ptr = req->request.data;
710 ptr += strlen("sysrq");
711 while (isspace(*ptr)) ptr++;
714 * With 'b', the system will shut down without a chance to reply,
715 * so in this case, we reply first.
718 mconsole_reply(req, "", 0, 0);
720 with_console(req, sysrq_proc, ptr);
723 void mconsole_sysrq(struct mc_request *req)
725 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
729 static void stack_proc(void *arg)
731 struct task_struct *from = current, *to = arg;
733 to->thread.saved_task = from;
734 switch_to(from, to, from);
738 * Mconsole stack trace
739 * Added by Allan Graves, Jeff Dike
740 * Dumps a stacks registers to the linux console.
743 void mconsole_stack(struct mc_request *req)
745 char *ptr = req->request.data;
746 int pid_requested= -1;
747 struct task_struct *to = NULL;
751 * 1) Send showregs output to mconsole.
752 * 2) Add a way to stack dump all pids.
755 ptr += strlen("stack");
756 while (isspace(*ptr))
760 * Should really check for multiple pids or reject bad args here
762 /* What do the arguments in mconsole_reply mean? */
763 if (sscanf(ptr, "%d", &pid_requested) == 0) {
764 mconsole_reply(req, "Please specify a pid", 1, 0);
768 to = find_task_by_pid(pid_requested);
769 if ((to == NULL) || (pid_requested == 0)) {
770 mconsole_reply(req, "Couldn't find that pid", 1, 0);
773 with_console(req, stack_proc, to);
777 * Changed by mconsole_setup, which is __setup, and called before SMP is
780 static char *notify_socket = NULL;
782 static int __init mconsole_init(void)
784 /* long to avoid size mismatch warnings from gcc */
789 if (umid_file_name("mconsole", file, sizeof(file)))
791 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
793 sock = os_create_unix_socket(file, sizeof(file), 1);
795 printk(KERN_ERR "Failed to initialize management console\n");
798 if (os_set_fd_block(sock, 0))
801 register_reboot_notifier(&reboot_notifier);
803 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
804 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
805 "mconsole", (void *)sock);
807 printk(KERN_ERR "Failed to get IRQ for management console\n");
811 if (notify_socket != NULL) {
812 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
813 if (notify_socket != NULL)
814 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
815 mconsole_socket_name,
816 strlen(mconsole_socket_name) + 1);
817 else printk(KERN_ERR "mconsole_setup failed to strdup "
821 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
822 MCONSOLE_VERSION, mconsole_socket_name);
830 __initcall(mconsole_init);
832 static int write_proc_mconsole(struct file *file, const char __user *buffer,
833 unsigned long count, void *data)
837 buf = kmalloc(count + 1, GFP_KERNEL);
841 if (copy_from_user(buf, buffer, count)) {
848 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
854 static int create_proc_mconsole(void)
856 struct proc_dir_entry *ent;
858 if (notify_socket == NULL)
861 ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
863 printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
868 ent->read_proc = NULL;
869 ent->write_proc = write_proc_mconsole;
873 static DEFINE_SPINLOCK(notify_spinlock);
875 void lock_notify(void)
877 spin_lock(¬ify_spinlock);
880 void unlock_notify(void)
882 spin_unlock(¬ify_spinlock);
885 __initcall(create_proc_mconsole);
887 #define NOTIFY "notify:"
889 static int mconsole_setup(char *str)
891 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
892 str += strlen(NOTIFY);
895 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
899 __setup("mconsole=", mconsole_setup);
901 __uml_help(mconsole_setup,
902 "mconsole=notify:<socket>\n"
903 " Requests that the mconsole driver send a message to the named Unix\n"
904 " socket containing the name of the mconsole socket. This also serves\n"
905 " to notify outside processes when UML has booted far enough to respond\n"
906 " to mconsole requests.\n\n"
909 static int notify_panic(struct notifier_block *self, unsigned long unused1,
914 if (notify_socket == NULL)
917 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
918 strlen(message) + 1);
922 static struct notifier_block panic_exit_notifier = {
923 .notifier_call = notify_panic,
928 static int add_notifier(void)
930 atomic_notifier_chain_register(&panic_notifier_list,
931 &panic_exit_notifier);
935 __initcall(add_notifier);
937 char *mconsole_notify_socket(void)
939 return notify_socket;
942 EXPORT_SYMBOL(mconsole_notify_socket);