1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
4 * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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);
102 void mconsole_version(struct mc_request *req)
106 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
107 utsname()->nodename, utsname()->release, utsname()->version,
109 mconsole_reply(req, version, 0, 0);
112 void mconsole_log(struct mc_request *req)
115 char *ptr = req->request.data;
117 ptr += strlen("log ");
119 len = req->len - (ptr - req->request.data);
120 printk(KERN_WARNING "%.*s", len, ptr);
121 mconsole_reply(req, "", 0, 0);
124 void mconsole_proc(struct mc_request *req)
126 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
131 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 len = kernel_read(file, buf, PAGE_SIZE - 1, &pos);
153 mconsole_reply(req, "Read of file failed", 1, 0);
156 /* Begin the file content on his own line. */
158 mconsole_reply(req, "\n", 0, 1);
162 mconsole_reply(req, buf, 0, (len > 0));
171 #define UML_MCONSOLE_HELPTEXT \
173 version - Get kernel version \n\
174 help - Print this message \n\
176 reboot - Reboot UML \n\
177 config <dev>=<config> - Add a new device to UML; \n\
178 same syntax as command line \n\
179 config <dev> - Query the configuration of a device \n\
180 remove <dev> - Remove a device from UML \n\
181 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
182 cad - invoke the Ctrl-Alt-Del handler \n\
183 stop - pause the UML; it will do nothing until it receives a 'go' \n\
184 go - continue the UML after a 'stop' \n\
185 log <string> - make UML enter <string> into the kernel log\n\
186 proc <file> - returns the contents of the UML's /proc/<file>\n\
187 stack <pid> - returns the stack of the specified pid\n\
190 void mconsole_help(struct mc_request *req)
192 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
195 void mconsole_halt(struct mc_request *req)
197 mconsole_reply(req, "", 0, 0);
201 void mconsole_reboot(struct mc_request *req)
203 mconsole_reply(req, "", 0, 0);
204 machine_restart(NULL);
207 void mconsole_cad(struct mc_request *req)
209 mconsole_reply(req, "", 0, 0);
213 void mconsole_go(struct mc_request *req)
215 mconsole_reply(req, "Not stopped", 1, 0);
218 void mconsole_stop(struct mc_request *req)
220 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
221 os_set_fd_block(req->originating_fd, 1);
222 mconsole_reply(req, "stopped", 0, 0);
224 if (!mconsole_get_request(req->originating_fd, req))
226 if (req->cmd->handler == mconsole_go)
228 if (req->cmd->handler == mconsole_stop) {
229 mconsole_reply(req, "Already stopped", 1, 0);
232 if (req->cmd->handler == mconsole_sysrq) {
233 struct pt_regs *old_regs;
234 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
236 set_irq_regs(old_regs);
239 (*req->cmd->handler)(req);
241 os_set_fd_block(req->originating_fd, 0);
242 mconsole_reply(req, "", 0, 0);
245 static DEFINE_SPINLOCK(mc_devices_lock);
246 static LIST_HEAD(mconsole_devices);
248 void mconsole_register_dev(struct mc_device *new)
250 spin_lock(&mc_devices_lock);
251 BUG_ON(!list_empty(&new->list));
252 list_add(&new->list, &mconsole_devices);
253 spin_unlock(&mc_devices_lock);
256 static struct mc_device *mconsole_find_dev(char *name)
258 struct list_head *ele;
259 struct mc_device *dev;
261 list_for_each(ele, &mconsole_devices) {
262 dev = list_entry(ele, struct mc_device, list);
263 if (!strncmp(name, dev->name, strlen(dev->name)))
269 #define UNPLUGGED_PER_PAGE \
270 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
272 struct unplugged_pages {
273 struct list_head list;
274 void *pages[UNPLUGGED_PER_PAGE];
277 static DEFINE_MUTEX(plug_mem_mutex);
278 static unsigned long long unplugged_pages_count = 0;
279 static LIST_HEAD(unplugged_pages);
280 static int unplug_index = UNPLUGGED_PER_PAGE;
282 static int mem_config(char *str, char **error_out)
284 unsigned long long diff;
285 int err = -EINVAL, i, add;
289 *error_out = "Expected '=' after 'mem'";
296 else if (str[0] == '+') {
300 *error_out = "Expected increment to start with '-' or '+'";
305 diff = memparse(str, &ret);
307 *error_out = "Failed to parse memory increment";
313 mutex_lock(&plug_mem_mutex);
314 for (i = 0; i < diff; i++) {
315 struct unplugged_pages *unplugged;
319 if (list_empty(&unplugged_pages))
322 unplugged = list_entry(unplugged_pages.next,
323 struct unplugged_pages, list);
324 if (unplug_index > 0)
325 addr = unplugged->pages[--unplug_index];
327 list_del(&unplugged->list);
329 unplug_index = UNPLUGGED_PER_PAGE;
332 free_page((unsigned long) addr);
333 unplugged_pages_count--;
338 page = alloc_page(GFP_ATOMIC);
342 unplugged = page_address(page);
343 if (unplug_index == UNPLUGGED_PER_PAGE) {
344 list_add(&unplugged->list, &unplugged_pages);
348 struct list_head *entry = unplugged_pages.next;
351 unplugged = list_entry(entry,
352 struct unplugged_pages,
354 err = os_drop_memory(addr, PAGE_SIZE);
356 printk(KERN_ERR "Failed to release "
357 "memory - errno = %d\n", err);
358 *error_out = "Failed to release memory";
361 unplugged->pages[unplug_index++] = addr;
364 unplugged_pages_count++;
370 mutex_unlock(&plug_mem_mutex);
375 static int mem_get_config(char *name, char *str, int size, char **error_out)
377 char buf[sizeof("18446744073709551615")];
380 sprintf(buf, "%ld", uml_physmem);
381 CONFIG_CHUNK(str, size, len, buf, 1);
386 static int mem_id(char **str, int *start_out, int *end_out)
394 static int mem_remove(int n, char **error_out)
396 *error_out = "Memory doesn't support the remove operation";
400 static struct mc_device mem_mc = {
401 .list = LIST_HEAD_INIT(mem_mc.list),
403 .config = mem_config,
404 .get_config = mem_get_config,
406 .remove = mem_remove,
409 static int __init mem_mc_init(void)
411 if (can_drop_memory())
412 mconsole_register_dev(&mem_mc);
413 else printk(KERN_ERR "Can't release memory to the host - memory "
414 "hotplug won't be supported\n");
418 __initcall(mem_mc_init);
420 #define CONFIG_BUF_SIZE 64
422 static void mconsole_get_config(int (*get_config)(char *, char *, int,
424 struct mc_request *req, char *name)
426 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
429 if (get_config == NULL) {
430 mconsole_reply(req, "No get_config routine defined", 1, 0);
435 size = ARRAY_SIZE(default_buf);
439 n = (*get_config)(name, buf, size, &error);
441 mconsole_reply(req, error, 1, 0);
446 mconsole_reply(req, buf, 0, 0);
450 if (buf != default_buf)
454 buf = kmalloc(size, GFP_KERNEL);
456 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
461 if (buf != default_buf)
465 void mconsole_config(struct mc_request *req)
467 struct mc_device *dev;
468 char *ptr = req->request.data, *name, *error_string = "";
471 ptr += strlen("config");
472 ptr = skip_spaces(ptr);
473 dev = mconsole_find_dev(ptr);
475 mconsole_reply(req, "Bad configuration option", 1, 0);
479 name = &ptr[strlen(dev->name)];
481 while ((*ptr != '=') && (*ptr != '\0'))
485 err = (*dev->config)(name, &error_string);
486 mconsole_reply(req, error_string, err, 0);
488 else mconsole_get_config(dev->get_config, req, name);
491 void mconsole_remove(struct mc_request *req)
493 struct mc_device *dev;
494 char *ptr = req->request.data, *err_msg = "";
496 int err, start, end, n;
498 ptr += strlen("remove");
499 ptr = skip_spaces(ptr);
500 dev = mconsole_find_dev(ptr);
502 mconsole_reply(req, "Bad remove option", 1, 0);
506 ptr = &ptr[strlen(dev->name)];
509 n = (*dev->id)(&ptr, &start, &end);
511 err_msg = "Couldn't parse device number";
514 else if ((n < start) || (n > end)) {
515 sprintf(error, "Invalid device number - must be between "
516 "%d and %d", start, end);
522 err = (*dev->remove)(n, &err_msg);
529 err_msg = "Device doesn't exist";
533 err_msg = "Device is currently open";
539 mconsole_reply(req, err_msg, err, 0);
542 struct mconsole_output {
543 struct list_head list;
544 struct mc_request *req;
547 static DEFINE_SPINLOCK(client_lock);
548 static LIST_HEAD(clients);
549 static char console_buf[MCONSOLE_MAX_DATA];
551 static void console_write(struct console *console, const char *string,
554 struct list_head *ele;
557 if (list_empty(&clients))
561 n = min((size_t) len, ARRAY_SIZE(console_buf));
562 strncpy(console_buf, string, n);
566 list_for_each(ele, &clients) {
567 struct mconsole_output *entry;
569 entry = list_entry(ele, struct mconsole_output, list);
570 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
575 static struct console mc_console = { .name = "mc",
576 .write = console_write,
577 .flags = CON_ENABLED,
580 static int mc_add_console(void)
582 register_console(&mc_console);
586 late_initcall(mc_add_console);
588 static void with_console(struct mc_request *req, void (*proc)(void *),
591 struct mconsole_output entry;
595 spin_lock_irqsave(&client_lock, flags);
596 list_add(&entry.list, &clients);
597 spin_unlock_irqrestore(&client_lock, flags);
601 mconsole_reply_len(req, "", 0, 0, 0);
603 spin_lock_irqsave(&client_lock, flags);
604 list_del(&entry.list);
605 spin_unlock_irqrestore(&client_lock, flags);
608 #ifdef CONFIG_MAGIC_SYSRQ
610 #include <linux/sysrq.h>
612 static void sysrq_proc(void *arg)
618 void mconsole_sysrq(struct mc_request *req)
620 char *ptr = req->request.data;
622 ptr += strlen("sysrq");
623 ptr = skip_spaces(ptr);
626 * With 'b', the system will shut down without a chance to reply,
627 * so in this case, we reply first.
630 mconsole_reply(req, "", 0, 0);
632 with_console(req, sysrq_proc, ptr);
635 void mconsole_sysrq(struct mc_request *req)
637 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
641 static void stack_proc(void *arg)
643 struct task_struct *task = arg;
645 show_stack(task, NULL);
649 * Mconsole stack trace
650 * Added by Allan Graves, Jeff Dike
651 * Dumps a stacks registers to the linux console.
654 void mconsole_stack(struct mc_request *req)
656 char *ptr = req->request.data;
657 int pid_requested= -1;
658 struct task_struct *to = NULL;
662 * 1) Send showregs output to mconsole.
663 * 2) Add a way to stack dump all pids.
666 ptr += strlen("stack");
667 ptr = skip_spaces(ptr);
670 * Should really check for multiple pids or reject bad args here
672 /* What do the arguments in mconsole_reply mean? */
673 if (sscanf(ptr, "%d", &pid_requested) == 0) {
674 mconsole_reply(req, "Please specify a pid", 1, 0);
678 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
679 if ((to == NULL) || (pid_requested == 0)) {
680 mconsole_reply(req, "Couldn't find that pid", 1, 0);
683 with_console(req, stack_proc, to);
687 * Changed by mconsole_setup, which is __setup, and called before SMP is
690 static char *notify_socket = NULL;
692 static int __init mconsole_init(void)
694 /* long to avoid size mismatch warnings from gcc */
697 char file[UNIX_PATH_MAX];
699 if (umid_file_name("mconsole", file, sizeof(file)))
701 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
703 sock = os_create_unix_socket(file, sizeof(file), 1);
705 printk(KERN_ERR "Failed to initialize management console\n");
708 if (os_set_fd_block(sock, 0))
711 register_reboot_notifier(&reboot_notifier);
713 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
714 IRQF_SHARED, "mconsole", (void *)sock);
716 printk(KERN_ERR "Failed to get IRQ for management console\n");
720 if (notify_socket != NULL) {
721 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
722 if (notify_socket != NULL)
723 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
724 mconsole_socket_name,
725 strlen(mconsole_socket_name) + 1);
726 else printk(KERN_ERR "mconsole_setup failed to strdup "
730 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
731 MCONSOLE_VERSION, mconsole_socket_name);
739 __initcall(mconsole_init);
741 static ssize_t mconsole_proc_write(struct file *file,
742 const char __user *buffer, size_t count, loff_t *pos)
746 buf = memdup_user_nul(buffer, count);
750 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
755 static const struct file_operations mconsole_proc_fops = {
756 .owner = THIS_MODULE,
757 .write = mconsole_proc_write,
758 .llseek = noop_llseek,
761 static int create_proc_mconsole(void)
763 struct proc_dir_entry *ent;
765 if (notify_socket == NULL)
768 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
770 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
776 static DEFINE_SPINLOCK(notify_spinlock);
778 void lock_notify(void)
780 spin_lock(¬ify_spinlock);
783 void unlock_notify(void)
785 spin_unlock(¬ify_spinlock);
788 __initcall(create_proc_mconsole);
790 #define NOTIFY "notify:"
792 static int mconsole_setup(char *str)
794 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
795 str += strlen(NOTIFY);
798 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
802 __setup("mconsole=", mconsole_setup);
804 __uml_help(mconsole_setup,
805 "mconsole=notify:<socket>\n"
806 " Requests that the mconsole driver send a message to the named Unix\n"
807 " socket containing the name of the mconsole socket. This also serves\n"
808 " to notify outside processes when UML has booted far enough to respond\n"
809 " to mconsole requests.\n\n"
812 static int notify_panic(struct notifier_block *self, unsigned long unused1,
817 if (notify_socket == NULL)
820 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
821 strlen(message) + 1);
825 static struct notifier_block panic_exit_notifier = {
826 .notifier_call = notify_panic,
831 static int add_notifier(void)
833 atomic_notifier_chain_register(&panic_notifier_list,
834 &panic_exit_notifier);
838 __initcall(add_notifier);
840 char *mconsole_notify_socket(void)
842 return notify_socket;
845 EXPORT_SYMBOL(mconsole_notify_socket);