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 "asm/uaccess.h"
24 #include "kern_util.h"
26 #include "mconsole_kern.h"
29 static int do_unlink_socket(struct notifier_block *notifier,
30 unsigned long what, void *data)
32 return mconsole_unlink_socket();
36 static struct notifier_block reboot_notifier = {
37 .notifier_call = do_unlink_socket,
41 /* Safe without explicit locking for now. Tasklets provide their own
42 * locking, and the interrupt handler is safe because it can't interrupt
43 * itself and it can only happen on CPU 0.
46 static LIST_HEAD(mc_requests);
48 static void mc_work_proc(struct work_struct *unused)
50 struct mconsole_entry *req;
53 while (!list_empty(&mc_requests)) {
54 local_irq_save(flags);
55 req = list_entry(mc_requests.next, struct mconsole_entry, list);
57 local_irq_restore(flags);
58 req->request.cmd->handler(&req->request);
63 static DECLARE_WORK(mconsole_work, mc_work_proc);
65 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
67 /* long to avoid size mismatch warnings from gcc */
69 struct mconsole_entry *new;
70 static struct mc_request req; /* that's OK */
73 while (mconsole_get_request(fd, &req)) {
74 if (req.cmd->context == MCONSOLE_INTR)
75 (*req.cmd->handler)(&req);
77 new = kmalloc(sizeof(*new), GFP_NOWAIT);
79 mconsole_reply(&req, "Out of memory", 1, 0);
82 new->request.regs = get_irq_regs()->regs;
83 list_add(&new->list, &mc_requests);
87 if (!list_empty(&mc_requests))
88 schedule_work(&mconsole_work);
89 reactivate_fd(fd, MCONSOLE_IRQ);
93 void mconsole_version(struct mc_request *req)
97 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
98 utsname()->nodename, utsname()->release, utsname()->version,
100 mconsole_reply(req, version, 0, 0);
103 void mconsole_log(struct mc_request *req)
106 char *ptr = req->request.data;
108 ptr += strlen("log ");
110 len = req->len - (ptr - req->request.data);
111 printk(KERN_WARNING "%.*s", len, ptr);
112 mconsole_reply(req, "", 0, 0);
115 /* This is a more convoluted version of mconsole_proc, which has some stability
116 * problems; however, we need it fixed, because it is expected that UML users
117 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
118 * show the real procfs content, not the ones from hppfs.*/
120 void mconsole_proc(struct mc_request *req)
123 struct file_system_type *proc;
124 struct super_block *super;
127 char *ptr = req->request.data, *buf;
129 ptr += strlen("proc");
130 while (isspace(*ptr)) ptr++;
132 proc = get_fs_type("proc");
134 mconsole_reply(req, "procfs not registered", 1, 0);
138 super = (*proc->get_sb)(proc, 0, NULL, NULL);
139 put_filesystem(proc);
141 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
144 up_write(&super->s_umount);
146 nd.dentry = super->s_root;
148 nd.flags = O_RDONLY + 1;
149 nd.last_type = LAST_ROOT;
151 /* START: it was experienced that the stability problems are closed
152 * if commenting out these two calls + the below read cycle. To
153 * make UML crash again, it was enough to readd either one.*/
154 err = link_path_walk(ptr, &nd);
156 mconsole_reply(req, "Failed to look up file", 1, 0);
160 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
162 mconsole_reply(req, "Failed to open file", 1, 0);
167 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
169 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
173 if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
175 n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
179 mconsole_reply(req, buf, 0, (n > 0));
182 mconsole_reply(req, "Read of file failed",
188 else mconsole_reply(req, "", 0, 0);
195 deactivate_super(super);
200 void mconsole_proc(struct mc_request *req)
207 char *ptr = req->request.data;
209 ptr += strlen("proc");
210 while (isspace(*ptr))
212 snprintf(path, sizeof(path), "/proc/%s", ptr);
214 fd = sys_open(path, 0, 0);
216 mconsole_reply(req, "Failed to open file", 1, 0);
217 printk(KERN_ERR "open %s: %d\n",path,fd);
221 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
223 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
228 len = sys_read(fd, buf, PAGE_SIZE-1);
230 mconsole_reply(req, "Read of file failed", 1, 0);
233 /* Begin the file content on his own line. */
235 mconsole_reply(req, "\n", 0, 1);
238 if (len == PAGE_SIZE-1) {
240 mconsole_reply(req, buf, 0, 1);
243 mconsole_reply(req, buf, 0, 0);
256 #define UML_MCONSOLE_HELPTEXT \
258 version - Get kernel version \n\
259 help - Print this message \n\
261 reboot - Reboot UML \n\
262 config <dev>=<config> - Add a new device to UML; \n\
263 same syntax as command line \n\
264 config <dev> - Query the configuration of a device \n\
265 remove <dev> - Remove a device from UML \n\
266 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
267 cad - invoke the Ctrl-Alt-Del handler \n\
268 stop - pause the UML; it will do nothing until it receives a 'go' \n\
269 go - continue the UML after a 'stop' \n\
270 log <string> - make UML enter <string> into the kernel log\n\
271 proc <file> - returns the contents of the UML's /proc/<file>\n\
272 stack <pid> - returns the stack of the specified pid\n\
275 void mconsole_help(struct mc_request *req)
277 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
280 void mconsole_halt(struct mc_request *req)
282 mconsole_reply(req, "", 0, 0);
286 void mconsole_reboot(struct mc_request *req)
288 mconsole_reply(req, "", 0, 0);
289 machine_restart(NULL);
292 void mconsole_cad(struct mc_request *req)
294 mconsole_reply(req, "", 0, 0);
298 void mconsole_go(struct mc_request *req)
300 mconsole_reply(req, "Not stopped", 1, 0);
303 void mconsole_stop(struct mc_request *req)
305 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
306 os_set_fd_block(req->originating_fd, 1);
307 mconsole_reply(req, "stopped", 0, 0);
309 if (!mconsole_get_request(req->originating_fd, req))
311 if (req->cmd->handler == mconsole_go)
313 if (req->cmd->handler == mconsole_stop) {
314 mconsole_reply(req, "Already stopped", 1, 0);
317 if (req->cmd->handler == mconsole_sysrq) {
318 struct pt_regs *old_regs;
319 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
321 set_irq_regs(old_regs);
324 (*req->cmd->handler)(req);
326 os_set_fd_block(req->originating_fd, 0);
327 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
328 mconsole_reply(req, "", 0, 0);
331 static DEFINE_SPINLOCK(mc_devices_lock);
332 static LIST_HEAD(mconsole_devices);
334 void mconsole_register_dev(struct mc_device *new)
336 spin_lock(&mc_devices_lock);
337 BUG_ON(!list_empty(&new->list));
338 list_add(&new->list, &mconsole_devices);
339 spin_unlock(&mc_devices_lock);
342 static struct mc_device *mconsole_find_dev(char *name)
344 struct list_head *ele;
345 struct mc_device *dev;
347 list_for_each(ele, &mconsole_devices) {
348 dev = list_entry(ele, struct mc_device, list);
349 if (!strncmp(name, dev->name, strlen(dev->name)))
355 #define UNPLUGGED_PER_PAGE \
356 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
358 struct unplugged_pages {
359 struct list_head list;
360 void *pages[UNPLUGGED_PER_PAGE];
363 static DECLARE_MUTEX(plug_mem_mutex);
364 static unsigned long long unplugged_pages_count = 0;
365 static LIST_HEAD(unplugged_pages);
366 static int unplug_index = UNPLUGGED_PER_PAGE;
368 static int mem_config(char *str, char **error_out)
370 unsigned long long diff;
371 int err = -EINVAL, i, add;
375 *error_out = "Expected '=' after 'mem'";
382 else if (str[0] == '+') {
386 *error_out = "Expected increment to start with '-' or '+'";
391 diff = memparse(str, &ret);
393 *error_out = "Failed to parse memory increment";
399 down(&plug_mem_mutex);
400 for (i = 0; i < diff; i++) {
401 struct unplugged_pages *unplugged;
405 if (list_empty(&unplugged_pages))
408 unplugged = list_entry(unplugged_pages.next,
409 struct unplugged_pages, list);
410 if (unplug_index > 0)
411 addr = unplugged->pages[--unplug_index];
413 list_del(&unplugged->list);
415 unplug_index = UNPLUGGED_PER_PAGE;
418 free_page((unsigned long) addr);
419 unplugged_pages_count--;
424 page = alloc_page(GFP_ATOMIC);
428 unplugged = page_address(page);
429 if (unplug_index == UNPLUGGED_PER_PAGE) {
430 list_add(&unplugged->list, &unplugged_pages);
434 struct list_head *entry = unplugged_pages.next;
437 unplugged = list_entry(entry,
438 struct unplugged_pages,
440 err = os_drop_memory(addr, PAGE_SIZE);
442 printk(KERN_ERR "Failed to release "
443 "memory - errno = %d\n", err);
444 *error_out = "Failed to release memory";
447 unplugged->pages[unplug_index++] = addr;
450 unplugged_pages_count++;
461 static int mem_get_config(char *name, char *str, int size, char **error_out)
463 char buf[sizeof("18446744073709551615")];
466 sprintf(buf, "%ld", uml_physmem);
467 CONFIG_CHUNK(str, size, len, buf, 1);
472 static int mem_id(char **str, int *start_out, int *end_out)
480 static int mem_remove(int n, char **error_out)
482 *error_out = "Memory doesn't support the remove operation";
486 static struct mc_device mem_mc = {
487 .list = LIST_HEAD_INIT(mem_mc.list),
489 .config = mem_config,
490 .get_config = mem_get_config,
492 .remove = mem_remove,
495 static int __init mem_mc_init(void)
497 if (can_drop_memory())
498 mconsole_register_dev(&mem_mc);
499 else printk(KERN_ERR "Can't release memory to the host - memory "
500 "hotplug won't be supported\n");
504 __initcall(mem_mc_init);
506 #define CONFIG_BUF_SIZE 64
508 static void mconsole_get_config(int (*get_config)(char *, char *, int,
510 struct mc_request *req, char *name)
512 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
515 if (get_config == NULL) {
516 mconsole_reply(req, "No get_config routine defined", 1, 0);
521 size = ARRAY_SIZE(default_buf);
525 n = (*get_config)(name, buf, size, &error);
527 mconsole_reply(req, error, 1, 0);
532 mconsole_reply(req, buf, 0, 0);
536 if (buf != default_buf)
540 buf = kmalloc(size, GFP_KERNEL);
542 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
547 if (buf != default_buf)
551 void mconsole_config(struct mc_request *req)
553 struct mc_device *dev;
554 char *ptr = req->request.data, *name, *error_string = "";
557 ptr += strlen("config");
558 while (isspace(*ptr))
560 dev = mconsole_find_dev(ptr);
562 mconsole_reply(req, "Bad configuration option", 1, 0);
566 name = &ptr[strlen(dev->name)];
568 while ((*ptr != '=') && (*ptr != '\0'))
572 err = (*dev->config)(name, &error_string);
573 mconsole_reply(req, error_string, err, 0);
575 else mconsole_get_config(dev->get_config, req, name);
578 void mconsole_remove(struct mc_request *req)
580 struct mc_device *dev;
581 char *ptr = req->request.data, *err_msg = "";
583 int err, start, end, n;
585 ptr += strlen("remove");
586 while (isspace(*ptr)) ptr++;
587 dev = mconsole_find_dev(ptr);
589 mconsole_reply(req, "Bad remove option", 1, 0);
593 ptr = &ptr[strlen(dev->name)];
596 n = (*dev->id)(&ptr, &start, &end);
598 err_msg = "Couldn't parse device number";
601 else if ((n < start) || (n > end)) {
602 sprintf(error, "Invalid device number - must be between "
603 "%d and %d", start, end);
609 err = (*dev->remove)(n, &err_msg);
616 err_msg = "Device doesn't exist";
620 err_msg = "Device is currently open";
626 mconsole_reply(req, err_msg, err, 0);
629 struct mconsole_output {
630 struct list_head list;
631 struct mc_request *req;
634 static DEFINE_SPINLOCK(client_lock);
635 static LIST_HEAD(clients);
636 static char console_buf[MCONSOLE_MAX_DATA];
638 static void console_write(struct console *console, const char *string,
641 struct list_head *ele;
644 if (list_empty(&clients))
648 n = min((size_t) len, ARRAY_SIZE(console_buf));
649 strncpy(console_buf, string, n);
653 list_for_each(ele, &clients) {
654 struct mconsole_output *entry;
656 entry = list_entry(ele, struct mconsole_output, list);
657 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
662 static struct console mc_console = { .name = "mc",
663 .write = console_write,
664 .flags = CON_ENABLED,
667 static int mc_add_console(void)
669 register_console(&mc_console);
673 late_initcall(mc_add_console);
675 static void with_console(struct mc_request *req, void (*proc)(void *),
678 struct mconsole_output entry;
682 spin_lock_irqsave(&client_lock, flags);
683 list_add(&entry.list, &clients);
684 spin_unlock_irqrestore(&client_lock, flags);
688 mconsole_reply_len(req, "", 0, 0, 0);
690 spin_lock_irqsave(&client_lock, flags);
691 list_del(&entry.list);
692 spin_unlock_irqrestore(&client_lock, flags);
695 #ifdef CONFIG_MAGIC_SYSRQ
697 #include <linux/sysrq.h>
699 static void sysrq_proc(void *arg)
702 handle_sysrq(*op, NULL);
705 void mconsole_sysrq(struct mc_request *req)
707 char *ptr = req->request.data;
709 ptr += strlen("sysrq");
710 while (isspace(*ptr)) ptr++;
713 * With 'b', the system will shut down without a chance to reply,
714 * so in this case, we reply first.
717 mconsole_reply(req, "", 0, 0);
719 with_console(req, sysrq_proc, ptr);
722 void mconsole_sysrq(struct mc_request *req)
724 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
728 static void stack_proc(void *arg)
730 struct task_struct *from = current, *to = arg;
732 to->thread.saved_task = from;
733 switch_to(from, to, from);
737 * Mconsole stack trace
738 * Added by Allan Graves, Jeff Dike
739 * Dumps a stacks registers to the linux console.
742 void mconsole_stack(struct mc_request *req)
744 char *ptr = req->request.data;
745 int pid_requested= -1;
746 struct task_struct *to = NULL;
750 * 1) Send showregs output to mconsole.
751 * 2) Add a way to stack dump all pids.
754 ptr += strlen("stack");
755 while (isspace(*ptr))
759 * Should really check for multiple pids or reject bad args here
761 /* What do the arguments in mconsole_reply mean? */
762 if (sscanf(ptr, "%d", &pid_requested) == 0) {
763 mconsole_reply(req, "Please specify a pid", 1, 0);
767 to = find_task_by_pid(pid_requested);
768 if ((to == NULL) || (pid_requested == 0)) {
769 mconsole_reply(req, "Couldn't find that pid", 1, 0);
772 with_console(req, stack_proc, to);
776 * Changed by mconsole_setup, which is __setup, and called before SMP is
779 static char *notify_socket = NULL;
781 static int __init mconsole_init(void)
783 /* long to avoid size mismatch warnings from gcc */
788 if (umid_file_name("mconsole", file, sizeof(file)))
790 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
792 sock = os_create_unix_socket(file, sizeof(file), 1);
794 printk(KERN_ERR "Failed to initialize management console\n");
797 if (os_set_fd_block(sock, 0))
800 register_reboot_notifier(&reboot_notifier);
802 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
803 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
804 "mconsole", (void *)sock);
806 printk(KERN_ERR "Failed to get IRQ for management console\n");
810 if (notify_socket != NULL) {
811 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
812 if (notify_socket != NULL)
813 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
814 mconsole_socket_name,
815 strlen(mconsole_socket_name) + 1);
816 else printk(KERN_ERR "mconsole_setup failed to strdup "
820 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
821 MCONSOLE_VERSION, mconsole_socket_name);
829 __initcall(mconsole_init);
831 static int write_proc_mconsole(struct file *file, const char __user *buffer,
832 unsigned long count, void *data)
836 buf = kmalloc(count + 1, GFP_KERNEL);
840 if (copy_from_user(buf, buffer, count)) {
847 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
853 static int create_proc_mconsole(void)
855 struct proc_dir_entry *ent;
857 if (notify_socket == NULL)
860 ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
862 printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
867 ent->read_proc = NULL;
868 ent->write_proc = write_proc_mconsole;
872 static DEFINE_SPINLOCK(notify_spinlock);
874 void lock_notify(void)
876 spin_lock(¬ify_spinlock);
879 void unlock_notify(void)
881 spin_unlock(¬ify_spinlock);
884 __initcall(create_proc_mconsole);
886 #define NOTIFY "notify:"
888 static int mconsole_setup(char *str)
890 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
891 str += strlen(NOTIFY);
894 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
898 __setup("mconsole=", mconsole_setup);
900 __uml_help(mconsole_setup,
901 "mconsole=notify:<socket>\n"
902 " Requests that the mconsole driver send a message to the named Unix\n"
903 " socket containing the name of the mconsole socket. This also serves\n"
904 " to notify outside processes when UML has booted far enough to respond\n"
905 " to mconsole requests.\n\n"
908 static int notify_panic(struct notifier_block *self, unsigned long unused1,
913 if (notify_socket == NULL)
916 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
917 strlen(message) + 1);
921 static struct notifier_block panic_exit_notifier = {
922 .notifier_call = notify_panic,
927 static int add_notifier(void)
929 atomic_notifier_chain_register(&panic_notifier_list,
930 &panic_exit_notifier);
934 __initcall(add_notifier);
936 char *mconsole_notify_socket(void)
938 return notify_socket;
941 EXPORT_SYMBOL(mconsole_notify_socket);