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/sched/debug.h>
17 #include <linux/proc_fs.h>
18 #include <linux/slab.h>
19 #include <linux/syscalls.h>
20 #include <linux/utsname.h>
21 #include <linux/socket.h>
23 #include <linux/workqueue.h>
24 #include <linux/mutex.h>
26 #include <linux/mount.h>
27 #include <linux/file.h>
28 #include <linux/uaccess.h>
29 #include <asm/switch_to.h>
34 #include <kern_util.h>
36 #include "mconsole_kern.h"
39 static int do_unlink_socket(struct notifier_block *notifier,
40 unsigned long what, void *data)
42 return mconsole_unlink_socket();
46 static struct notifier_block reboot_notifier = {
47 .notifier_call = do_unlink_socket,
51 /* Safe without explicit locking for now. Tasklets provide their own
52 * locking, and the interrupt handler is safe because it can't interrupt
53 * itself and it can only happen on CPU 0.
56 static LIST_HEAD(mc_requests);
58 static void mc_work_proc(struct work_struct *unused)
60 struct mconsole_entry *req;
63 while (!list_empty(&mc_requests)) {
64 local_irq_save(flags);
65 req = list_entry(mc_requests.next, struct mconsole_entry, list);
67 local_irq_restore(flags);
68 req->request.cmd->handler(&req->request);
73 static DECLARE_WORK(mconsole_work, mc_work_proc);
75 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
77 /* long to avoid size mismatch warnings from gcc */
79 struct mconsole_entry *new;
80 static struct mc_request req; /* that's OK */
83 while (mconsole_get_request(fd, &req)) {
84 if (req.cmd->context == MCONSOLE_INTR)
85 (*req.cmd->handler)(&req);
87 new = kmalloc(sizeof(*new), GFP_NOWAIT);
89 mconsole_reply(&req, "Out of memory", 1, 0);
92 new->request.regs = get_irq_regs()->regs;
93 list_add(&new->list, &mc_requests);
97 if (!list_empty(&mc_requests))
98 schedule_work(&mconsole_work);
99 reactivate_fd(fd, MCONSOLE_IRQ);
103 void mconsole_version(struct mc_request *req)
107 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
108 utsname()->nodename, utsname()->release, utsname()->version,
110 mconsole_reply(req, version, 0, 0);
113 void mconsole_log(struct mc_request *req)
116 char *ptr = req->request.data;
118 ptr += strlen("log ");
120 len = req->len - (ptr - req->request.data);
121 printk(KERN_WARNING "%.*s", len, ptr);
122 mconsole_reply(req, "", 0, 0);
125 void mconsole_proc(struct mc_request *req)
127 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
132 char *ptr = req->request.data;
134 ptr += strlen("proc");
135 ptr = skip_spaces(ptr);
137 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
139 mconsole_reply(req, "Failed to open file", 1, 0);
140 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
144 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
146 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
151 loff_t pos = file->f_pos;
152 mm_segment_t old_fs = get_fs();
154 len = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
158 mconsole_reply(req, "Read of file failed", 1, 0);
161 /* Begin the file content on his own line. */
163 mconsole_reply(req, "\n", 0, 1);
167 mconsole_reply(req, buf, 0, (len > 0));
176 #define UML_MCONSOLE_HELPTEXT \
178 version - Get kernel version \n\
179 help - Print this message \n\
181 reboot - Reboot UML \n\
182 config <dev>=<config> - Add a new device to UML; \n\
183 same syntax as command line \n\
184 config <dev> - Query the configuration of a device \n\
185 remove <dev> - Remove a device from UML \n\
186 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
187 cad - invoke the Ctrl-Alt-Del handler \n\
188 stop - pause the UML; it will do nothing until it receives a 'go' \n\
189 go - continue the UML after a 'stop' \n\
190 log <string> - make UML enter <string> into the kernel log\n\
191 proc <file> - returns the contents of the UML's /proc/<file>\n\
192 stack <pid> - returns the stack of the specified pid\n\
195 void mconsole_help(struct mc_request *req)
197 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
200 void mconsole_halt(struct mc_request *req)
202 mconsole_reply(req, "", 0, 0);
206 void mconsole_reboot(struct mc_request *req)
208 mconsole_reply(req, "", 0, 0);
209 machine_restart(NULL);
212 void mconsole_cad(struct mc_request *req)
214 mconsole_reply(req, "", 0, 0);
218 void mconsole_go(struct mc_request *req)
220 mconsole_reply(req, "Not stopped", 1, 0);
223 void mconsole_stop(struct mc_request *req)
225 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
226 os_set_fd_block(req->originating_fd, 1);
227 mconsole_reply(req, "stopped", 0, 0);
229 if (!mconsole_get_request(req->originating_fd, req))
231 if (req->cmd->handler == mconsole_go)
233 if (req->cmd->handler == mconsole_stop) {
234 mconsole_reply(req, "Already stopped", 1, 0);
237 if (req->cmd->handler == mconsole_sysrq) {
238 struct pt_regs *old_regs;
239 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
241 set_irq_regs(old_regs);
244 (*req->cmd->handler)(req);
246 os_set_fd_block(req->originating_fd, 0);
247 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
248 mconsole_reply(req, "", 0, 0);
251 static DEFINE_SPINLOCK(mc_devices_lock);
252 static LIST_HEAD(mconsole_devices);
254 void mconsole_register_dev(struct mc_device *new)
256 spin_lock(&mc_devices_lock);
257 BUG_ON(!list_empty(&new->list));
258 list_add(&new->list, &mconsole_devices);
259 spin_unlock(&mc_devices_lock);
262 static struct mc_device *mconsole_find_dev(char *name)
264 struct list_head *ele;
265 struct mc_device *dev;
267 list_for_each(ele, &mconsole_devices) {
268 dev = list_entry(ele, struct mc_device, list);
269 if (!strncmp(name, dev->name, strlen(dev->name)))
275 #define UNPLUGGED_PER_PAGE \
276 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
278 struct unplugged_pages {
279 struct list_head list;
280 void *pages[UNPLUGGED_PER_PAGE];
283 static DEFINE_MUTEX(plug_mem_mutex);
284 static unsigned long long unplugged_pages_count = 0;
285 static LIST_HEAD(unplugged_pages);
286 static int unplug_index = UNPLUGGED_PER_PAGE;
288 static int mem_config(char *str, char **error_out)
290 unsigned long long diff;
291 int err = -EINVAL, i, add;
295 *error_out = "Expected '=' after 'mem'";
302 else if (str[0] == '+') {
306 *error_out = "Expected increment to start with '-' or '+'";
311 diff = memparse(str, &ret);
313 *error_out = "Failed to parse memory increment";
319 mutex_lock(&plug_mem_mutex);
320 for (i = 0; i < diff; i++) {
321 struct unplugged_pages *unplugged;
325 if (list_empty(&unplugged_pages))
328 unplugged = list_entry(unplugged_pages.next,
329 struct unplugged_pages, list);
330 if (unplug_index > 0)
331 addr = unplugged->pages[--unplug_index];
333 list_del(&unplugged->list);
335 unplug_index = UNPLUGGED_PER_PAGE;
338 free_page((unsigned long) addr);
339 unplugged_pages_count--;
344 page = alloc_page(GFP_ATOMIC);
348 unplugged = page_address(page);
349 if (unplug_index == UNPLUGGED_PER_PAGE) {
350 list_add(&unplugged->list, &unplugged_pages);
354 struct list_head *entry = unplugged_pages.next;
357 unplugged = list_entry(entry,
358 struct unplugged_pages,
360 err = os_drop_memory(addr, PAGE_SIZE);
362 printk(KERN_ERR "Failed to release "
363 "memory - errno = %d\n", err);
364 *error_out = "Failed to release memory";
367 unplugged->pages[unplug_index++] = addr;
370 unplugged_pages_count++;
376 mutex_unlock(&plug_mem_mutex);
381 static int mem_get_config(char *name, char *str, int size, char **error_out)
383 char buf[sizeof("18446744073709551615")];
386 sprintf(buf, "%ld", uml_physmem);
387 CONFIG_CHUNK(str, size, len, buf, 1);
392 static int mem_id(char **str, int *start_out, int *end_out)
400 static int mem_remove(int n, char **error_out)
402 *error_out = "Memory doesn't support the remove operation";
406 static struct mc_device mem_mc = {
407 .list = LIST_HEAD_INIT(mem_mc.list),
409 .config = mem_config,
410 .get_config = mem_get_config,
412 .remove = mem_remove,
415 static int __init mem_mc_init(void)
417 if (can_drop_memory())
418 mconsole_register_dev(&mem_mc);
419 else printk(KERN_ERR "Can't release memory to the host - memory "
420 "hotplug won't be supported\n");
424 __initcall(mem_mc_init);
426 #define CONFIG_BUF_SIZE 64
428 static void mconsole_get_config(int (*get_config)(char *, char *, int,
430 struct mc_request *req, char *name)
432 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
435 if (get_config == NULL) {
436 mconsole_reply(req, "No get_config routine defined", 1, 0);
441 size = ARRAY_SIZE(default_buf);
445 n = (*get_config)(name, buf, size, &error);
447 mconsole_reply(req, error, 1, 0);
452 mconsole_reply(req, buf, 0, 0);
456 if (buf != default_buf)
460 buf = kmalloc(size, GFP_KERNEL);
462 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
467 if (buf != default_buf)
471 void mconsole_config(struct mc_request *req)
473 struct mc_device *dev;
474 char *ptr = req->request.data, *name, *error_string = "";
477 ptr += strlen("config");
478 ptr = skip_spaces(ptr);
479 dev = mconsole_find_dev(ptr);
481 mconsole_reply(req, "Bad configuration option", 1, 0);
485 name = &ptr[strlen(dev->name)];
487 while ((*ptr != '=') && (*ptr != '\0'))
491 err = (*dev->config)(name, &error_string);
492 mconsole_reply(req, error_string, err, 0);
494 else mconsole_get_config(dev->get_config, req, name);
497 void mconsole_remove(struct mc_request *req)
499 struct mc_device *dev;
500 char *ptr = req->request.data, *err_msg = "";
502 int err, start, end, n;
504 ptr += strlen("remove");
505 ptr = skip_spaces(ptr);
506 dev = mconsole_find_dev(ptr);
508 mconsole_reply(req, "Bad remove option", 1, 0);
512 ptr = &ptr[strlen(dev->name)];
515 n = (*dev->id)(&ptr, &start, &end);
517 err_msg = "Couldn't parse device number";
520 else if ((n < start) || (n > end)) {
521 sprintf(error, "Invalid device number - must be between "
522 "%d and %d", start, end);
528 err = (*dev->remove)(n, &err_msg);
535 err_msg = "Device doesn't exist";
539 err_msg = "Device is currently open";
545 mconsole_reply(req, err_msg, err, 0);
548 struct mconsole_output {
549 struct list_head list;
550 struct mc_request *req;
553 static DEFINE_SPINLOCK(client_lock);
554 static LIST_HEAD(clients);
555 static char console_buf[MCONSOLE_MAX_DATA];
557 static void console_write(struct console *console, const char *string,
560 struct list_head *ele;
563 if (list_empty(&clients))
567 n = min((size_t) len, ARRAY_SIZE(console_buf));
568 strncpy(console_buf, string, n);
572 list_for_each(ele, &clients) {
573 struct mconsole_output *entry;
575 entry = list_entry(ele, struct mconsole_output, list);
576 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
581 static struct console mc_console = { .name = "mc",
582 .write = console_write,
583 .flags = CON_ENABLED,
586 static int mc_add_console(void)
588 register_console(&mc_console);
592 late_initcall(mc_add_console);
594 static void with_console(struct mc_request *req, void (*proc)(void *),
597 struct mconsole_output entry;
601 spin_lock_irqsave(&client_lock, flags);
602 list_add(&entry.list, &clients);
603 spin_unlock_irqrestore(&client_lock, flags);
607 mconsole_reply_len(req, "", 0, 0, 0);
609 spin_lock_irqsave(&client_lock, flags);
610 list_del(&entry.list);
611 spin_unlock_irqrestore(&client_lock, flags);
614 #ifdef CONFIG_MAGIC_SYSRQ
616 #include <linux/sysrq.h>
618 static void sysrq_proc(void *arg)
624 void mconsole_sysrq(struct mc_request *req)
626 char *ptr = req->request.data;
628 ptr += strlen("sysrq");
629 ptr = skip_spaces(ptr);
632 * With 'b', the system will shut down without a chance to reply,
633 * so in this case, we reply first.
636 mconsole_reply(req, "", 0, 0);
638 with_console(req, sysrq_proc, ptr);
641 void mconsole_sysrq(struct mc_request *req)
643 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
647 static void stack_proc(void *arg)
649 struct task_struct *task = arg;
651 show_stack(task, NULL);
655 * Mconsole stack trace
656 * Added by Allan Graves, Jeff Dike
657 * Dumps a stacks registers to the linux console.
660 void mconsole_stack(struct mc_request *req)
662 char *ptr = req->request.data;
663 int pid_requested= -1;
664 struct task_struct *to = NULL;
668 * 1) Send showregs output to mconsole.
669 * 2) Add a way to stack dump all pids.
672 ptr += strlen("stack");
673 ptr = skip_spaces(ptr);
676 * Should really check for multiple pids or reject bad args here
678 /* What do the arguments in mconsole_reply mean? */
679 if (sscanf(ptr, "%d", &pid_requested) == 0) {
680 mconsole_reply(req, "Please specify a pid", 1, 0);
684 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
685 if ((to == NULL) || (pid_requested == 0)) {
686 mconsole_reply(req, "Couldn't find that pid", 1, 0);
689 with_console(req, stack_proc, to);
693 * Changed by mconsole_setup, which is __setup, and called before SMP is
696 static char *notify_socket = NULL;
698 static int __init mconsole_init(void)
700 /* long to avoid size mismatch warnings from gcc */
703 char file[UNIX_PATH_MAX];
705 if (umid_file_name("mconsole", file, sizeof(file)))
707 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
709 sock = os_create_unix_socket(file, sizeof(file), 1);
711 printk(KERN_ERR "Failed to initialize management console\n");
714 if (os_set_fd_block(sock, 0))
717 register_reboot_notifier(&reboot_notifier);
719 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
720 IRQF_SHARED, "mconsole", (void *)sock);
722 printk(KERN_ERR "Failed to get IRQ for management console\n");
726 if (notify_socket != NULL) {
727 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
728 if (notify_socket != NULL)
729 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
730 mconsole_socket_name,
731 strlen(mconsole_socket_name) + 1);
732 else printk(KERN_ERR "mconsole_setup failed to strdup "
736 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
737 MCONSOLE_VERSION, mconsole_socket_name);
745 __initcall(mconsole_init);
747 static ssize_t mconsole_proc_write(struct file *file,
748 const char __user *buffer, size_t count, loff_t *pos)
752 buf = memdup_user_nul(buffer, count);
756 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
761 static const struct file_operations mconsole_proc_fops = {
762 .owner = THIS_MODULE,
763 .write = mconsole_proc_write,
764 .llseek = noop_llseek,
767 static int create_proc_mconsole(void)
769 struct proc_dir_entry *ent;
771 if (notify_socket == NULL)
774 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
776 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
782 static DEFINE_SPINLOCK(notify_spinlock);
784 void lock_notify(void)
786 spin_lock(¬ify_spinlock);
789 void unlock_notify(void)
791 spin_unlock(¬ify_spinlock);
794 __initcall(create_proc_mconsole);
796 #define NOTIFY "notify:"
798 static int mconsole_setup(char *str)
800 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
801 str += strlen(NOTIFY);
804 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
808 __setup("mconsole=", mconsole_setup);
810 __uml_help(mconsole_setup,
811 "mconsole=notify:<socket>\n"
812 " Requests that the mconsole driver send a message to the named Unix\n"
813 " socket containing the name of the mconsole socket. This also serves\n"
814 " to notify outside processes when UML has booted far enough to respond\n"
815 " to mconsole requests.\n\n"
818 static int notify_panic(struct notifier_block *self, unsigned long unused1,
823 if (notify_socket == NULL)
826 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
827 strlen(message) + 1);
831 static struct notifier_block panic_exit_notifier = {
832 .notifier_call = notify_panic,
837 static int add_notifier(void)
839 atomic_notifier_chain_register(&panic_notifier_list,
840 &panic_exit_notifier);
844 __initcall(add_notifier);
846 char *mconsole_notify_socket(void)
848 return notify_socket;
851 EXPORT_SYMBOL(mconsole_notify_socket);