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>
25 #include <asm/switch_to.h>
30 #include "kern_util.h"
32 #include "mconsole_kern.h"
35 static int do_unlink_socket(struct notifier_block *notifier,
36 unsigned long what, void *data)
38 return mconsole_unlink_socket();
42 static struct notifier_block reboot_notifier = {
43 .notifier_call = do_unlink_socket,
47 /* Safe without explicit locking for now. Tasklets provide their own
48 * locking, and the interrupt handler is safe because it can't interrupt
49 * itself and it can only happen on CPU 0.
52 static LIST_HEAD(mc_requests);
54 static void mc_work_proc(struct work_struct *unused)
56 struct mconsole_entry *req;
59 while (!list_empty(&mc_requests)) {
60 local_irq_save(flags);
61 req = list_entry(mc_requests.next, struct mconsole_entry, list);
63 local_irq_restore(flags);
64 req->request.cmd->handler(&req->request);
69 static DECLARE_WORK(mconsole_work, mc_work_proc);
71 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
73 /* long to avoid size mismatch warnings from gcc */
75 struct mconsole_entry *new;
76 static struct mc_request req; /* that's OK */
79 while (mconsole_get_request(fd, &req)) {
80 if (req.cmd->context == MCONSOLE_INTR)
81 (*req.cmd->handler)(&req);
83 new = kmalloc(sizeof(*new), GFP_NOWAIT);
85 mconsole_reply(&req, "Out of memory", 1, 0);
88 new->request.regs = get_irq_regs()->regs;
89 list_add(&new->list, &mc_requests);
93 if (!list_empty(&mc_requests))
94 schedule_work(&mconsole_work);
95 reactivate_fd(fd, MCONSOLE_IRQ);
99 void mconsole_version(struct mc_request *req)
103 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
104 utsname()->nodename, utsname()->release, utsname()->version,
106 mconsole_reply(req, version, 0, 0);
109 void mconsole_log(struct mc_request *req)
112 char *ptr = req->request.data;
114 ptr += strlen("log ");
116 len = req->len - (ptr - req->request.data);
117 printk(KERN_WARNING "%.*s", len, ptr);
118 mconsole_reply(req, "", 0, 0);
121 /* This is a more convoluted version of mconsole_proc, which has some stability
122 * problems; however, we need it fixed, because it is expected that UML users
123 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
124 * show the real procfs content, not the ones from hppfs.*/
126 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 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY);
139 mconsole_reply(req, "Failed to open file", 1, 0);
143 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
145 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
149 if (file->f_op->read) {
153 n = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
154 file_pos_write(file, pos);
158 mconsole_reply(req, buf, 0, (n > 0));
161 mconsole_reply(req, "Read of file failed",
167 else mconsole_reply(req, "", 0, 0);
177 void mconsole_proc(struct mc_request *req)
184 char *ptr = req->request.data;
186 ptr += strlen("proc");
187 ptr = skip_spaces(ptr);
188 snprintf(path, sizeof(path), "/proc/%s", ptr);
190 fd = sys_open(path, 0, 0);
192 mconsole_reply(req, "Failed to open file", 1, 0);
193 printk(KERN_ERR "open %s: %d\n",path,fd);
197 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
199 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
204 len = sys_read(fd, buf, PAGE_SIZE-1);
206 mconsole_reply(req, "Read of file failed", 1, 0);
209 /* Begin the file content on his own line. */
211 mconsole_reply(req, "\n", 0, 1);
214 if (len == PAGE_SIZE-1) {
216 mconsole_reply(req, buf, 0, 1);
219 mconsole_reply(req, buf, 0, 0);
232 #define UML_MCONSOLE_HELPTEXT \
234 version - Get kernel version \n\
235 help - Print this message \n\
237 reboot - Reboot UML \n\
238 config <dev>=<config> - Add a new device to UML; \n\
239 same syntax as command line \n\
240 config <dev> - Query the configuration of a device \n\
241 remove <dev> - Remove a device from UML \n\
242 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
243 cad - invoke the Ctrl-Alt-Del handler \n\
244 stop - pause the UML; it will do nothing until it receives a 'go' \n\
245 go - continue the UML after a 'stop' \n\
246 log <string> - make UML enter <string> into the kernel log\n\
247 proc <file> - returns the contents of the UML's /proc/<file>\n\
248 stack <pid> - returns the stack of the specified pid\n\
251 void mconsole_help(struct mc_request *req)
253 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
256 void mconsole_halt(struct mc_request *req)
258 mconsole_reply(req, "", 0, 0);
262 void mconsole_reboot(struct mc_request *req)
264 mconsole_reply(req, "", 0, 0);
265 machine_restart(NULL);
268 void mconsole_cad(struct mc_request *req)
270 mconsole_reply(req, "", 0, 0);
274 void mconsole_go(struct mc_request *req)
276 mconsole_reply(req, "Not stopped", 1, 0);
279 void mconsole_stop(struct mc_request *req)
281 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
282 os_set_fd_block(req->originating_fd, 1);
283 mconsole_reply(req, "stopped", 0, 0);
285 if (!mconsole_get_request(req->originating_fd, req))
287 if (req->cmd->handler == mconsole_go)
289 if (req->cmd->handler == mconsole_stop) {
290 mconsole_reply(req, "Already stopped", 1, 0);
293 if (req->cmd->handler == mconsole_sysrq) {
294 struct pt_regs *old_regs;
295 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
297 set_irq_regs(old_regs);
300 (*req->cmd->handler)(req);
302 os_set_fd_block(req->originating_fd, 0);
303 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
304 mconsole_reply(req, "", 0, 0);
307 static DEFINE_SPINLOCK(mc_devices_lock);
308 static LIST_HEAD(mconsole_devices);
310 void mconsole_register_dev(struct mc_device *new)
312 spin_lock(&mc_devices_lock);
313 BUG_ON(!list_empty(&new->list));
314 list_add(&new->list, &mconsole_devices);
315 spin_unlock(&mc_devices_lock);
318 static struct mc_device *mconsole_find_dev(char *name)
320 struct list_head *ele;
321 struct mc_device *dev;
323 list_for_each(ele, &mconsole_devices) {
324 dev = list_entry(ele, struct mc_device, list);
325 if (!strncmp(name, dev->name, strlen(dev->name)))
331 #define UNPLUGGED_PER_PAGE \
332 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
334 struct unplugged_pages {
335 struct list_head list;
336 void *pages[UNPLUGGED_PER_PAGE];
339 static DEFINE_MUTEX(plug_mem_mutex);
340 static unsigned long long unplugged_pages_count = 0;
341 static LIST_HEAD(unplugged_pages);
342 static int unplug_index = UNPLUGGED_PER_PAGE;
344 static int mem_config(char *str, char **error_out)
346 unsigned long long diff;
347 int err = -EINVAL, i, add;
351 *error_out = "Expected '=' after 'mem'";
358 else if (str[0] == '+') {
362 *error_out = "Expected increment to start with '-' or '+'";
367 diff = memparse(str, &ret);
369 *error_out = "Failed to parse memory increment";
375 mutex_lock(&plug_mem_mutex);
376 for (i = 0; i < diff; i++) {
377 struct unplugged_pages *unplugged;
381 if (list_empty(&unplugged_pages))
384 unplugged = list_entry(unplugged_pages.next,
385 struct unplugged_pages, list);
386 if (unplug_index > 0)
387 addr = unplugged->pages[--unplug_index];
389 list_del(&unplugged->list);
391 unplug_index = UNPLUGGED_PER_PAGE;
394 free_page((unsigned long) addr);
395 unplugged_pages_count--;
400 page = alloc_page(GFP_ATOMIC);
404 unplugged = page_address(page);
405 if (unplug_index == UNPLUGGED_PER_PAGE) {
406 list_add(&unplugged->list, &unplugged_pages);
410 struct list_head *entry = unplugged_pages.next;
413 unplugged = list_entry(entry,
414 struct unplugged_pages,
416 err = os_drop_memory(addr, PAGE_SIZE);
418 printk(KERN_ERR "Failed to release "
419 "memory - errno = %d\n", err);
420 *error_out = "Failed to release memory";
423 unplugged->pages[unplug_index++] = addr;
426 unplugged_pages_count++;
432 mutex_unlock(&plug_mem_mutex);
437 static int mem_get_config(char *name, char *str, int size, char **error_out)
439 char buf[sizeof("18446744073709551615")];
442 sprintf(buf, "%ld", uml_physmem);
443 CONFIG_CHUNK(str, size, len, buf, 1);
448 static int mem_id(char **str, int *start_out, int *end_out)
456 static int mem_remove(int n, char **error_out)
458 *error_out = "Memory doesn't support the remove operation";
462 static struct mc_device mem_mc = {
463 .list = LIST_HEAD_INIT(mem_mc.list),
465 .config = mem_config,
466 .get_config = mem_get_config,
468 .remove = mem_remove,
471 static int __init mem_mc_init(void)
473 if (can_drop_memory())
474 mconsole_register_dev(&mem_mc);
475 else printk(KERN_ERR "Can't release memory to the host - memory "
476 "hotplug won't be supported\n");
480 __initcall(mem_mc_init);
482 #define CONFIG_BUF_SIZE 64
484 static void mconsole_get_config(int (*get_config)(char *, char *, int,
486 struct mc_request *req, char *name)
488 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
491 if (get_config == NULL) {
492 mconsole_reply(req, "No get_config routine defined", 1, 0);
497 size = ARRAY_SIZE(default_buf);
501 n = (*get_config)(name, buf, size, &error);
503 mconsole_reply(req, error, 1, 0);
508 mconsole_reply(req, buf, 0, 0);
512 if (buf != default_buf)
516 buf = kmalloc(size, GFP_KERNEL);
518 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
523 if (buf != default_buf)
527 void mconsole_config(struct mc_request *req)
529 struct mc_device *dev;
530 char *ptr = req->request.data, *name, *error_string = "";
533 ptr += strlen("config");
534 ptr = skip_spaces(ptr);
535 dev = mconsole_find_dev(ptr);
537 mconsole_reply(req, "Bad configuration option", 1, 0);
541 name = &ptr[strlen(dev->name)];
543 while ((*ptr != '=') && (*ptr != '\0'))
547 err = (*dev->config)(name, &error_string);
548 mconsole_reply(req, error_string, err, 0);
550 else mconsole_get_config(dev->get_config, req, name);
553 void mconsole_remove(struct mc_request *req)
555 struct mc_device *dev;
556 char *ptr = req->request.data, *err_msg = "";
558 int err, start, end, n;
560 ptr += strlen("remove");
561 ptr = skip_spaces(ptr);
562 dev = mconsole_find_dev(ptr);
564 mconsole_reply(req, "Bad remove option", 1, 0);
568 ptr = &ptr[strlen(dev->name)];
571 n = (*dev->id)(&ptr, &start, &end);
573 err_msg = "Couldn't parse device number";
576 else if ((n < start) || (n > end)) {
577 sprintf(error, "Invalid device number - must be between "
578 "%d and %d", start, end);
584 err = (*dev->remove)(n, &err_msg);
591 err_msg = "Device doesn't exist";
595 err_msg = "Device is currently open";
601 mconsole_reply(req, err_msg, err, 0);
604 struct mconsole_output {
605 struct list_head list;
606 struct mc_request *req;
609 static DEFINE_SPINLOCK(client_lock);
610 static LIST_HEAD(clients);
611 static char console_buf[MCONSOLE_MAX_DATA];
613 static void console_write(struct console *console, const char *string,
616 struct list_head *ele;
619 if (list_empty(&clients))
623 n = min((size_t) len, ARRAY_SIZE(console_buf));
624 strncpy(console_buf, string, n);
628 list_for_each(ele, &clients) {
629 struct mconsole_output *entry;
631 entry = list_entry(ele, struct mconsole_output, list);
632 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
637 static struct console mc_console = { .name = "mc",
638 .write = console_write,
639 .flags = CON_ENABLED,
642 static int mc_add_console(void)
644 register_console(&mc_console);
648 late_initcall(mc_add_console);
650 static void with_console(struct mc_request *req, void (*proc)(void *),
653 struct mconsole_output entry;
657 spin_lock_irqsave(&client_lock, flags);
658 list_add(&entry.list, &clients);
659 spin_unlock_irqrestore(&client_lock, flags);
663 mconsole_reply_len(req, "", 0, 0, 0);
665 spin_lock_irqsave(&client_lock, flags);
666 list_del(&entry.list);
667 spin_unlock_irqrestore(&client_lock, flags);
670 #ifdef CONFIG_MAGIC_SYSRQ
672 #include <linux/sysrq.h>
674 static void sysrq_proc(void *arg)
680 void mconsole_sysrq(struct mc_request *req)
682 char *ptr = req->request.data;
684 ptr += strlen("sysrq");
685 ptr = skip_spaces(ptr);
688 * With 'b', the system will shut down without a chance to reply,
689 * so in this case, we reply first.
692 mconsole_reply(req, "", 0, 0);
694 with_console(req, sysrq_proc, ptr);
697 void mconsole_sysrq(struct mc_request *req)
699 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
703 static void stack_proc(void *arg)
705 struct task_struct *from = current, *to = arg;
707 to->thread.saved_task = from;
708 switch_to(from, to, from);
712 * Mconsole stack trace
713 * Added by Allan Graves, Jeff Dike
714 * Dumps a stacks registers to the linux console.
717 void mconsole_stack(struct mc_request *req)
719 char *ptr = req->request.data;
720 int pid_requested= -1;
721 struct task_struct *to = NULL;
725 * 1) Send showregs output to mconsole.
726 * 2) Add a way to stack dump all pids.
729 ptr += strlen("stack");
730 ptr = skip_spaces(ptr);
733 * Should really check for multiple pids or reject bad args here
735 /* What do the arguments in mconsole_reply mean? */
736 if (sscanf(ptr, "%d", &pid_requested) == 0) {
737 mconsole_reply(req, "Please specify a pid", 1, 0);
741 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
742 if ((to == NULL) || (pid_requested == 0)) {
743 mconsole_reply(req, "Couldn't find that pid", 1, 0);
746 with_console(req, stack_proc, to);
750 * Changed by mconsole_setup, which is __setup, and called before SMP is
753 static char *notify_socket = NULL;
755 static int __init mconsole_init(void)
757 /* long to avoid size mismatch warnings from gcc */
760 char file[UNIX_PATH_MAX];
762 if (umid_file_name("mconsole", file, sizeof(file)))
764 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
766 sock = os_create_unix_socket(file, sizeof(file), 1);
768 printk(KERN_ERR "Failed to initialize management console\n");
771 if (os_set_fd_block(sock, 0))
774 register_reboot_notifier(&reboot_notifier);
776 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
777 IRQF_SHARED | IRQF_SAMPLE_RANDOM,
778 "mconsole", (void *)sock);
780 printk(KERN_ERR "Failed to get IRQ for management console\n");
784 if (notify_socket != NULL) {
785 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
786 if (notify_socket != NULL)
787 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
788 mconsole_socket_name,
789 strlen(mconsole_socket_name) + 1);
790 else printk(KERN_ERR "mconsole_setup failed to strdup "
794 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
795 MCONSOLE_VERSION, mconsole_socket_name);
803 __initcall(mconsole_init);
805 static ssize_t mconsole_proc_write(struct file *file,
806 const char __user *buffer, size_t count, loff_t *pos)
810 buf = kmalloc(count + 1, GFP_KERNEL);
814 if (copy_from_user(buf, buffer, count)) {
821 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
827 static const struct file_operations mconsole_proc_fops = {
828 .owner = THIS_MODULE,
829 .write = mconsole_proc_write,
830 .llseek = noop_llseek,
833 static int create_proc_mconsole(void)
835 struct proc_dir_entry *ent;
837 if (notify_socket == NULL)
840 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
842 printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
849 static DEFINE_SPINLOCK(notify_spinlock);
851 void lock_notify(void)
853 spin_lock(¬ify_spinlock);
856 void unlock_notify(void)
858 spin_unlock(¬ify_spinlock);
861 __initcall(create_proc_mconsole);
863 #define NOTIFY "notify:"
865 static int mconsole_setup(char *str)
867 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
868 str += strlen(NOTIFY);
871 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
875 __setup("mconsole=", mconsole_setup);
877 __uml_help(mconsole_setup,
878 "mconsole=notify:<socket>\n"
879 " Requests that the mconsole driver send a message to the named Unix\n"
880 " socket containing the name of the mconsole socket. This also serves\n"
881 " to notify outside processes when UML has booted far enough to respond\n"
882 " to mconsole requests.\n\n"
885 static int notify_panic(struct notifier_block *self, unsigned long unused1,
890 if (notify_socket == NULL)
893 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
894 strlen(message) + 1);
898 static struct notifier_block panic_exit_notifier = {
899 .notifier_call = notify_panic,
904 static int add_notifier(void)
906 atomic_notifier_chain_register(&panic_notifier_list,
907 &panic_exit_notifier);
911 __initcall(add_notifier);
913 char *mconsole_notify_socket(void)
915 return notify_socket;
918 EXPORT_SYMBOL(mconsole_notify_socket);