2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3 * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
4 * Licensed under the GPL
7 #include "linux/kernel.h"
8 #include "linux/slab.h"
9 #include "linux/init.h"
10 #include "linux/notifier.h"
11 #include "linux/reboot.h"
12 #include "linux/utsname.h"
13 #include "linux/ctype.h"
14 #include "linux/interrupt.h"
15 #include "linux/sysrq.h"
16 #include "linux/workqueue.h"
17 #include "linux/module.h"
18 #include "linux/file.h"
20 #include "linux/namei.h"
21 #include "linux/proc_fs.h"
22 #include "linux/syscalls.h"
23 #include "linux/list.h"
25 #include "linux/console.h"
27 #include "asm/uaccess.h"
28 #include "kern_util.h"
31 #include "mconsole_kern.h"
37 static int do_unlink_socket(struct notifier_block *notifier,
38 unsigned long what, void *data)
40 return(mconsole_unlink_socket());
44 static struct notifier_block reboot_notifier = {
45 .notifier_call = do_unlink_socket,
49 /* Safe without explicit locking for now. Tasklets provide their own
50 * locking, and the interrupt handler is safe because it can't interrupt
51 * itself and it can only happen on CPU 0.
54 static LIST_HEAD(mc_requests);
56 static void mc_work_proc(struct work_struct *unused)
58 struct mconsole_entry *req;
61 while(!list_empty(&mc_requests)){
62 local_irq_save(flags);
63 req = list_entry(mc_requests.next, struct mconsole_entry,
66 local_irq_restore(flags);
67 req->request.cmd->handler(&req->request);
72 static DECLARE_WORK(mconsole_work, mc_work_proc);
74 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
76 /* long to avoid size mismatch warnings from gcc */
78 struct mconsole_entry *new;
79 static struct mc_request req; /* that's OK */
82 while (mconsole_get_request(fd, &req)){
83 if(req.cmd->context == MCONSOLE_INTR)
84 (*req.cmd->handler)(&req);
86 new = kmalloc(sizeof(*new), GFP_NOWAIT);
88 mconsole_reply(&req, "Out of memory", 1, 0);
91 new->request.regs = get_irq_regs()->regs;
92 list_add(&new->list, &mc_requests);
96 if(!list_empty(&mc_requests))
97 schedule_work(&mconsole_work);
98 reactivate_fd(fd, MCONSOLE_IRQ);
102 void mconsole_version(struct mc_request *req)
106 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
107 utsname()->nodename, utsname()->release,
108 utsname()->version, utsname()->machine);
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("%.*s", len, ptr);
121 mconsole_reply(req, "", 0, 0);
124 /* This is a more convoluted version of mconsole_proc, which has some stability
125 * problems; however, we need it fixed, because it is expected that UML users
126 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
127 * show the real procfs content, not the ones from hppfs.*/
129 void mconsole_proc(struct mc_request *req)
132 struct file_system_type *proc;
133 struct super_block *super;
136 char *ptr = req->request.data, *buf;
138 ptr += strlen("proc");
139 while(isspace(*ptr)) ptr++;
141 proc = get_fs_type("proc");
143 mconsole_reply(req, "procfs not registered", 1, 0);
147 super = (*proc->get_sb)(proc, 0, NULL, NULL);
148 put_filesystem(proc);
150 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
153 up_write(&super->s_umount);
155 nd.dentry = super->s_root;
157 nd.flags = O_RDONLY + 1;
158 nd.last_type = LAST_ROOT;
160 /* START: it was experienced that the stability problems are closed
161 * if commenting out these two calls + the below read cycle. To
162 * make UML crash again, it was enough to readd either one.*/
163 err = link_path_walk(ptr, &nd);
165 mconsole_reply(req, "Failed to look up file", 1, 0);
169 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
171 mconsole_reply(req, "Failed to open file", 1, 0);
176 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
178 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
182 if((file->f_op != NULL) && (file->f_op->read != NULL)){
184 n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
188 mconsole_reply(req, buf, 0, (n > 0));
191 mconsole_reply(req, "Read of file failed",
197 else mconsole_reply(req, "", 0, 0);
204 deactivate_super(super);
209 void mconsole_proc(struct mc_request *req)
216 char *ptr = req->request.data;
218 ptr += strlen("proc");
219 while(isspace(*ptr)) ptr++;
220 snprintf(path, sizeof(path), "/proc/%s", ptr);
222 fd = sys_open(path, 0, 0);
224 mconsole_reply(req, "Failed to open file", 1, 0);
225 printk("open %s: %d\n",path,fd);
229 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
231 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
236 len = sys_read(fd, buf, PAGE_SIZE-1);
238 mconsole_reply(req, "Read of file failed", 1, 0);
241 /*Begin the file content on his own line.*/
243 mconsole_reply(req, "\n", 0, 1);
246 if (len == PAGE_SIZE-1) {
248 mconsole_reply(req, buf, 0, 1);
251 mconsole_reply(req, buf, 0, 0);
264 #define UML_MCONSOLE_HELPTEXT \
266 version - Get kernel version \n\
267 help - Print this message \n\
269 reboot - Reboot UML \n\
270 config <dev>=<config> - Add a new device to UML; \n\
271 same syntax as command line \n\
272 config <dev> - Query the configuration of a device \n\
273 remove <dev> - Remove a device from UML \n\
274 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
275 cad - invoke the Ctrl-Alt-Del handler \n\
276 stop - pause the UML; it will do nothing until it receives a 'go' \n\
277 go - continue the UML after a 'stop' \n\
278 log <string> - make UML enter <string> into the kernel log\n\
279 proc <file> - returns the contents of the UML's /proc/<file>\n\
280 stack <pid> - returns the stack of the specified pid\n\
283 void mconsole_help(struct mc_request *req)
285 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
288 void mconsole_halt(struct mc_request *req)
290 mconsole_reply(req, "", 0, 0);
294 void mconsole_reboot(struct mc_request *req)
296 mconsole_reply(req, "", 0, 0);
297 machine_restart(NULL);
300 void mconsole_cad(struct mc_request *req)
302 mconsole_reply(req, "", 0, 0);
306 void mconsole_go(struct mc_request *req)
308 mconsole_reply(req, "Not stopped", 1, 0);
311 void mconsole_stop(struct mc_request *req)
313 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
314 os_set_fd_block(req->originating_fd, 1);
315 mconsole_reply(req, "stopped", 0, 0);
316 while (mconsole_get_request(req->originating_fd, req)) {
317 if (req->cmd->handler == mconsole_go)
319 if (req->cmd->handler == mconsole_stop) {
320 mconsole_reply(req, "Already stopped", 1, 0);
323 if (req->cmd->handler == mconsole_sysrq) {
324 struct pt_regs *old_regs;
325 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
327 set_irq_regs(old_regs);
330 (*req->cmd->handler)(req);
332 os_set_fd_block(req->originating_fd, 0);
333 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
334 mconsole_reply(req, "", 0, 0);
337 static DEFINE_SPINLOCK(mc_devices_lock);
338 static LIST_HEAD(mconsole_devices);
340 void mconsole_register_dev(struct mc_device *new)
342 spin_lock(&mc_devices_lock);
343 BUG_ON(!list_empty(&new->list));
344 list_add(&new->list, &mconsole_devices);
345 spin_unlock(&mc_devices_lock);
348 static struct mc_device *mconsole_find_dev(char *name)
350 struct list_head *ele;
351 struct mc_device *dev;
353 list_for_each(ele, &mconsole_devices){
354 dev = list_entry(ele, struct mc_device, list);
355 if(!strncmp(name, dev->name, strlen(dev->name)))
361 #define UNPLUGGED_PER_PAGE \
362 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
364 struct unplugged_pages {
365 struct list_head list;
366 void *pages[UNPLUGGED_PER_PAGE];
369 static DECLARE_MUTEX(plug_mem_mutex);
370 static unsigned long long unplugged_pages_count = 0;
371 static LIST_HEAD(unplugged_pages);
372 static int unplug_index = UNPLUGGED_PER_PAGE;
374 static int mem_config(char *str, char **error_out)
376 unsigned long long diff;
377 int err = -EINVAL, i, add;
381 *error_out = "Expected '=' after 'mem'";
388 else if(str[0] == '+'){
392 *error_out = "Expected increment to start with '-' or '+'";
397 diff = memparse(str, &ret);
399 *error_out = "Failed to parse memory increment";
405 down(&plug_mem_mutex);
406 for(i = 0; i < diff; i++){
407 struct unplugged_pages *unplugged;
411 if(list_empty(&unplugged_pages))
414 unplugged = list_entry(unplugged_pages.next,
415 struct unplugged_pages, list);
417 addr = unplugged->pages[--unplug_index];
419 list_del(&unplugged->list);
421 unplug_index = UNPLUGGED_PER_PAGE;
424 free_page((unsigned long) addr);
425 unplugged_pages_count--;
430 page = alloc_page(GFP_ATOMIC);
434 unplugged = page_address(page);
435 if(unplug_index == UNPLUGGED_PER_PAGE){
436 list_add(&unplugged->list, &unplugged_pages);
440 struct list_head *entry = unplugged_pages.next;
443 unplugged = list_entry(entry,
444 struct unplugged_pages,
446 err = os_drop_memory(addr, PAGE_SIZE);
448 printk("Failed to release memory - "
449 "errno = %d\n", err);
450 *error_out = "Failed to release memory";
453 unplugged->pages[unplug_index++] = addr;
456 unplugged_pages_count++;
467 static int mem_get_config(char *name, char *str, int size, char **error_out)
469 char buf[sizeof("18446744073709551615")];
472 sprintf(buf, "%ld", uml_physmem);
473 CONFIG_CHUNK(str, size, len, buf, 1);
478 static int mem_id(char **str, int *start_out, int *end_out)
486 static int mem_remove(int n, char **error_out)
488 *error_out = "Memory doesn't support the remove operation";
492 static struct mc_device mem_mc = {
493 .list = LIST_HEAD_INIT(mem_mc.list),
495 .config = mem_config,
496 .get_config = mem_get_config,
498 .remove = mem_remove,
501 static int __init mem_mc_init(void)
503 if(can_drop_memory())
504 mconsole_register_dev(&mem_mc);
505 else printk("Can't release memory to the host - memory hotplug won't "
510 __initcall(mem_mc_init);
512 #define CONFIG_BUF_SIZE 64
514 static void mconsole_get_config(int (*get_config)(char *, char *, int,
516 struct mc_request *req, char *name)
518 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
521 if(get_config == NULL){
522 mconsole_reply(req, "No get_config routine defined", 1, 0);
527 size = ARRAY_SIZE(default_buf);
531 n = (*get_config)(name, buf, size, &error);
533 mconsole_reply(req, error, 1, 0);
538 mconsole_reply(req, buf, 0, 0);
542 if(buf != default_buf)
546 buf = kmalloc(size, GFP_KERNEL);
548 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
553 if(buf != default_buf)
557 void mconsole_config(struct mc_request *req)
559 struct mc_device *dev;
560 char *ptr = req->request.data, *name, *error_string = "";
563 ptr += strlen("config");
564 while(isspace(*ptr)) ptr++;
565 dev = mconsole_find_dev(ptr);
567 mconsole_reply(req, "Bad configuration option", 1, 0);
571 name = &ptr[strlen(dev->name)];
573 while((*ptr != '=') && (*ptr != '\0'))
577 err = (*dev->config)(name, &error_string);
578 mconsole_reply(req, error_string, err, 0);
580 else mconsole_get_config(dev->get_config, req, name);
583 void mconsole_remove(struct mc_request *req)
585 struct mc_device *dev;
586 char *ptr = req->request.data, *err_msg = "";
588 int err, start, end, n;
590 ptr += strlen("remove");
591 while(isspace(*ptr)) ptr++;
592 dev = mconsole_find_dev(ptr);
594 mconsole_reply(req, "Bad remove option", 1, 0);
598 ptr = &ptr[strlen(dev->name)];
601 n = (*dev->id)(&ptr, &start, &end);
603 err_msg = "Couldn't parse device number";
606 else if((n < start) || (n > end)){
607 sprintf(error, "Invalid device number - must be between "
608 "%d and %d", start, end);
614 err = (*dev->remove)(n, &err_msg);
621 err_msg = "Device doesn't exist";
625 err_msg = "Device is currently open";
631 mconsole_reply(req, err_msg, err, 0);
634 struct mconsole_output {
635 struct list_head list;
636 struct mc_request *req;
639 static DEFINE_SPINLOCK(client_lock);
640 static LIST_HEAD(clients);
641 static char console_buf[MCONSOLE_MAX_DATA];
642 static int console_index = 0;
644 static void console_write(struct console *console, const char *string,
647 struct list_head *ele;
650 if(list_empty(&clients))
654 n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
655 strncpy(&console_buf[console_index], string, n);
662 list_for_each(ele, &clients){
663 struct mconsole_output *entry;
665 entry = list_entry(ele, struct mconsole_output, list);
666 mconsole_reply_len(entry->req, console_buf,
667 console_index, 0, 1);
674 static struct console mc_console = { .name = "mc",
675 .write = console_write,
676 .flags = CON_ENABLED,
679 static int mc_add_console(void)
681 register_console(&mc_console);
685 late_initcall(mc_add_console);
687 static void with_console(struct mc_request *req, void (*proc)(void *),
690 struct mconsole_output entry;
694 spin_lock_irqsave(&client_lock, flags);
695 list_add(&entry.list, &clients);
696 spin_unlock_irqrestore(&client_lock, flags);
700 mconsole_reply_len(req, console_buf, console_index, 0, 0);
703 spin_lock_irqsave(&client_lock, flags);
704 list_del(&entry.list);
705 spin_unlock_irqrestore(&client_lock, flags);
708 #ifdef CONFIG_MAGIC_SYSRQ
709 static void sysrq_proc(void *arg)
712 handle_sysrq(*op, NULL);
715 void mconsole_sysrq(struct mc_request *req)
717 char *ptr = req->request.data;
719 ptr += strlen("sysrq");
720 while(isspace(*ptr)) ptr++;
722 /* With 'b', the system will shut down without a chance to reply,
723 * so in this case, we reply first.
726 mconsole_reply(req, "", 0, 0);
728 with_console(req, sysrq_proc, ptr);
731 void mconsole_sysrq(struct mc_request *req)
733 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
737 static void stack_proc(void *arg)
739 struct task_struct *from = current, *to = arg;
741 to->thread.saved_task = from;
742 switch_to(from, to, from);
745 /* Mconsole stack trace
746 * Added by Allan Graves, Jeff Dike
747 * Dumps a stacks registers to the linux console.
750 void mconsole_stack(struct mc_request *req)
752 char *ptr = req->request.data;
753 int pid_requested= -1;
754 struct task_struct *from = NULL;
755 struct task_struct *to = NULL;
758 * 1) Send showregs output to mconsole.
759 * 2) Add a way to stack dump all pids.
762 ptr += strlen("stack");
763 while(isspace(*ptr)) ptr++;
765 /* Should really check for multiple pids or reject bad args here */
766 /* What do the arguments in mconsole_reply mean? */
767 if(sscanf(ptr, "%d", &pid_requested) == 0){
768 mconsole_reply(req, "Please specify a pid", 1, 0);
774 to = find_task_by_pid(pid_requested);
775 if((to == NULL) || (pid_requested == 0)) {
776 mconsole_reply(req, "Couldn't find that pid", 1, 0);
779 with_console(req, stack_proc, to);
782 /* Changed by mconsole_setup, which is __setup, and called before SMP is
785 static char *notify_socket = NULL;
787 static int __init mconsole_init(void)
789 /* long to avoid size mismatch warnings from gcc */
794 if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
795 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
797 sock = os_create_unix_socket(file, sizeof(file), 1);
799 printk("Failed to initialize management console\n");
803 register_reboot_notifier(&reboot_notifier);
805 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
806 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
807 "mconsole", (void *)sock);
809 printk("Failed to get IRQ for management console\n");
813 if(notify_socket != NULL){
814 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
815 if(notify_socket != NULL)
816 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
817 mconsole_socket_name,
818 strlen(mconsole_socket_name) + 1);
819 else printk(KERN_ERR "mconsole_setup failed to strdup "
823 printk("mconsole (version %d) initialized on %s\n",
824 MCONSOLE_VERSION, mconsole_socket_name);
828 __initcall(mconsole_init);
830 static int write_proc_mconsole(struct file *file, const char __user *buffer,
831 unsigned long count, void *data)
835 buf = kmalloc(count + 1, GFP_KERNEL);
839 if(copy_from_user(buf, buffer, count)){
846 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
852 static int create_proc_mconsole(void)
854 struct proc_dir_entry *ent;
856 if(notify_socket == NULL) return(0);
858 ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
860 printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
864 ent->read_proc = NULL;
865 ent->write_proc = write_proc_mconsole;
869 static DEFINE_SPINLOCK(notify_spinlock);
871 void lock_notify(void)
873 spin_lock(¬ify_spinlock);
876 void unlock_notify(void)
878 spin_unlock(¬ify_spinlock);
881 __initcall(create_proc_mconsole);
883 #define NOTIFY "=notify:"
885 static int mconsole_setup(char *str)
887 if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
888 str += strlen(NOTIFY);
891 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
895 __setup("mconsole", mconsole_setup);
897 __uml_help(mconsole_setup,
898 "mconsole=notify:<socket>\n"
899 " Requests that the mconsole driver send a message to the named Unix\n"
900 " socket containing the name of the mconsole socket. This also serves\n"
901 " to notify outside processes when UML has booted far enough to respond\n"
902 " to mconsole requests.\n\n"
905 static int notify_panic(struct notifier_block *self, unsigned long unused1,
910 if(notify_socket == NULL) return(0);
912 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
913 strlen(message) + 1);
917 static struct notifier_block panic_exit_notifier = {
918 .notifier_call = notify_panic,
923 static int add_notifier(void)
925 atomic_notifier_chain_register(&panic_notifier_list,
926 &panic_exit_notifier);
930 __initcall(add_notifier);
932 char *mconsole_notify_socket(void)
934 return(notify_socket);
937 EXPORT_SYMBOL(mconsole_notify_socket);