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/panic_notifier.h>
16 #include <linux/reboot.h>
17 #include <linux/sched/debug.h>
18 #include <linux/proc_fs.h>
19 #include <linux/slab.h>
20 #include <linux/syscalls.h>
21 #include <linux/utsname.h>
22 #include <linux/socket.h>
24 #include <linux/workqueue.h>
25 #include <linux/mutex.h>
27 #include <linux/mount.h>
28 #include <linux/file.h>
29 #include <linux/uaccess.h>
30 #include <asm/switch_to.h>
35 #include <kern_util.h>
37 #include "mconsole_kern.h"
40 static struct vfsmount
*proc_mnt
= NULL
;
42 static int do_unlink_socket(struct notifier_block
*notifier
,
43 unsigned long what
, void *data
)
45 return mconsole_unlink_socket();
49 static struct notifier_block reboot_notifier
= {
50 .notifier_call
= do_unlink_socket
,
54 /* Safe without explicit locking for now. Tasklets provide their own
55 * locking, and the interrupt handler is safe because it can't interrupt
56 * itself and it can only happen on CPU 0.
59 static LIST_HEAD(mc_requests
);
61 static void mc_work_proc(struct work_struct
*unused
)
63 struct mconsole_entry
*req
;
66 while (!list_empty(&mc_requests
)) {
67 local_irq_save(flags
);
68 req
= list_entry(mc_requests
.next
, struct mconsole_entry
, list
);
70 local_irq_restore(flags
);
71 req
->request
.cmd
->handler(&req
->request
);
76 static DECLARE_WORK(mconsole_work
, mc_work_proc
);
78 static irqreturn_t
mconsole_interrupt(int irq
, void *dev_id
)
80 /* long to avoid size mismatch warnings from gcc */
82 struct mconsole_entry
*new;
83 static struct mc_request req
; /* that's OK */
86 while (mconsole_get_request(fd
, &req
)) {
87 if (req
.cmd
->context
== MCONSOLE_INTR
)
88 (*req
.cmd
->handler
)(&req
);
90 new = kmalloc(sizeof(*new), GFP_NOWAIT
);
92 mconsole_reply(&req
, "Out of memory", 1, 0);
95 new->request
.regs
= get_irq_regs()->regs
;
96 list_add(&new->list
, &mc_requests
);
100 if (!list_empty(&mc_requests
))
101 schedule_work(&mconsole_work
);
105 void mconsole_version(struct mc_request
*req
)
109 sprintf(version
, "%s %s %s %s %s", utsname()->sysname
,
110 utsname()->nodename
, utsname()->release
, utsname()->version
,
112 mconsole_reply(req
, version
, 0, 0);
115 void mconsole_log(struct mc_request
*req
)
118 char *ptr
= req
->request
.data
;
120 ptr
+= strlen("log ");
122 len
= req
->len
- (ptr
- req
->request
.data
);
123 printk(KERN_WARNING
"%.*s", len
, ptr
);
124 mconsole_reply(req
, "", 0, 0);
127 void mconsole_proc(struct mc_request
*req
)
129 struct vfsmount
*mnt
= proc_mnt
;
134 char *ptr
= req
->request
.data
;
137 ptr
+= strlen("proc");
138 ptr
= skip_spaces(ptr
);
141 mconsole_reply(req
, "Proc not available", 1, 0);
144 file
= file_open_root_mnt(mnt
, ptr
, O_RDONLY
, 0);
146 mconsole_reply(req
, "Failed to open file", 1, 0);
147 printk(KERN_ERR
"open /proc/%s: %ld\n", ptr
, PTR_ERR(file
));
151 buf
= kmalloc(PAGE_SIZE
, GFP_KERNEL
);
153 mconsole_reply(req
, "Failed to allocate buffer", 1, 0);
158 len
= kernel_read(file
, buf
, PAGE_SIZE
- 1, &pos
);
160 mconsole_reply(req
, "Read of file failed", 1, 0);
163 /* Begin the file content on his own line. */
165 mconsole_reply(req
, "\n", 0, 1);
169 mconsole_reply(req
, buf
, 0, (len
> 0));
178 #define UML_MCONSOLE_HELPTEXT \
180 version - Get kernel version \n\
181 help - Print this message \n\
183 reboot - Reboot UML \n\
184 config <dev>=<config> - Add a new device to UML; \n\
185 same syntax as command line \n\
186 config <dev> - Query the configuration of a device \n\
187 remove <dev> - Remove a device from UML \n\
188 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
189 cad - invoke the Ctrl-Alt-Del handler \n\
190 stop - pause the UML; it will do nothing until it receives a 'go' \n\
191 go - continue the UML after a 'stop' \n\
192 log <string> - make UML enter <string> into the kernel log\n\
193 proc <file> - returns the contents of the UML's /proc/<file>\n\
194 stack <pid> - returns the stack of the specified pid\n\
197 void mconsole_help(struct mc_request
*req
)
199 mconsole_reply(req
, UML_MCONSOLE_HELPTEXT
, 0, 0);
202 void mconsole_halt(struct mc_request
*req
)
204 mconsole_reply(req
, "", 0, 0);
208 void mconsole_reboot(struct mc_request
*req
)
210 mconsole_reply(req
, "", 0, 0);
211 machine_restart(NULL
);
214 void mconsole_cad(struct mc_request
*req
)
216 mconsole_reply(req
, "", 0, 0);
220 void mconsole_go(struct mc_request
*req
)
222 mconsole_reply(req
, "Not stopped", 1, 0);
225 void mconsole_stop(struct mc_request
*req
)
227 deactivate_fd(req
->originating_fd
, MCONSOLE_IRQ
);
228 os_set_fd_block(req
->originating_fd
, 1);
229 mconsole_reply(req
, "stopped", 0, 0);
231 if (!mconsole_get_request(req
->originating_fd
, req
))
233 if (req
->cmd
->handler
== mconsole_go
)
235 if (req
->cmd
->handler
== mconsole_stop
) {
236 mconsole_reply(req
, "Already stopped", 1, 0);
239 if (req
->cmd
->handler
== mconsole_sysrq
) {
240 struct pt_regs
*old_regs
;
241 old_regs
= set_irq_regs((struct pt_regs
*)&req
->regs
);
243 set_irq_regs(old_regs
);
246 (*req
->cmd
->handler
)(req
);
248 os_set_fd_block(req
->originating_fd
, 0);
249 mconsole_reply(req
, "", 0, 0);
252 static DEFINE_SPINLOCK(mc_devices_lock
);
253 static LIST_HEAD(mconsole_devices
);
255 void mconsole_register_dev(struct mc_device
*new)
257 spin_lock(&mc_devices_lock
);
258 BUG_ON(!list_empty(&new->list
));
259 list_add(&new->list
, &mconsole_devices
);
260 spin_unlock(&mc_devices_lock
);
263 static struct mc_device
*mconsole_find_dev(char *name
)
265 struct list_head
*ele
;
266 struct mc_device
*dev
;
268 list_for_each(ele
, &mconsole_devices
) {
269 dev
= list_entry(ele
, struct mc_device
, list
);
270 if (!strncmp(name
, dev
->name
, strlen(dev
->name
)))
276 #define UNPLUGGED_PER_PAGE \
277 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
279 struct unplugged_pages
{
280 struct list_head list
;
281 void *pages
[UNPLUGGED_PER_PAGE
];
284 static DEFINE_MUTEX(plug_mem_mutex
);
285 static unsigned long long unplugged_pages_count
= 0;
286 static LIST_HEAD(unplugged_pages
);
287 static int unplug_index
= UNPLUGGED_PER_PAGE
;
289 static int mem_config(char *str
, char **error_out
)
291 unsigned long long diff
;
292 int err
= -EINVAL
, i
, add
;
296 *error_out
= "Expected '=' after 'mem'";
303 else if (str
[0] == '+') {
307 *error_out
= "Expected increment to start with '-' or '+'";
312 diff
= memparse(str
, &ret
);
314 *error_out
= "Failed to parse memory increment";
320 mutex_lock(&plug_mem_mutex
);
321 for (i
= 0; i
< diff
; i
++) {
322 struct unplugged_pages
*unplugged
;
326 if (list_empty(&unplugged_pages
))
329 unplugged
= list_entry(unplugged_pages
.next
,
330 struct unplugged_pages
, list
);
331 if (unplug_index
> 0)
332 addr
= unplugged
->pages
[--unplug_index
];
334 list_del(&unplugged
->list
);
336 unplug_index
= UNPLUGGED_PER_PAGE
;
339 free_page((unsigned long) addr
);
340 unplugged_pages_count
--;
345 page
= alloc_page(GFP_ATOMIC
);
349 unplugged
= page_address(page
);
350 if (unplug_index
== UNPLUGGED_PER_PAGE
) {
351 list_add(&unplugged
->list
, &unplugged_pages
);
355 struct list_head
*entry
= unplugged_pages
.next
;
358 unplugged
= list_entry(entry
,
359 struct unplugged_pages
,
361 err
= os_drop_memory(addr
, PAGE_SIZE
);
363 printk(KERN_ERR
"Failed to release "
364 "memory - errno = %d\n", err
);
365 *error_out
= "Failed to release memory";
368 unplugged
->pages
[unplug_index
++] = addr
;
371 unplugged_pages_count
++;
377 mutex_unlock(&plug_mem_mutex
);
382 static int mem_get_config(char *name
, char *str
, int size
, char **error_out
)
384 char buf
[sizeof("18446744073709551615")];
387 sprintf(buf
, "%ld", uml_physmem
);
388 CONFIG_CHUNK(str
, size
, len
, buf
, 1);
393 static int mem_id(char **str
, int *start_out
, int *end_out
)
401 static int mem_remove(int n
, char **error_out
)
403 *error_out
= "Memory doesn't support the remove operation";
407 static struct mc_device mem_mc
= {
408 .list
= LIST_HEAD_INIT(mem_mc
.list
),
410 .config
= mem_config
,
411 .get_config
= mem_get_config
,
413 .remove
= mem_remove
,
416 static int __init
mem_mc_init(void)
418 if (can_drop_memory())
419 mconsole_register_dev(&mem_mc
);
420 else printk(KERN_ERR
"Can't release memory to the host - memory "
421 "hotplug won't be supported\n");
425 __initcall(mem_mc_init
);
427 #define CONFIG_BUF_SIZE 64
429 static void mconsole_get_config(int (*get_config
)(char *, char *, int,
431 struct mc_request
*req
, char *name
)
433 char default_buf
[CONFIG_BUF_SIZE
], *error
, *buf
;
436 if (get_config
== NULL
) {
437 mconsole_reply(req
, "No get_config routine defined", 1, 0);
442 size
= ARRAY_SIZE(default_buf
);
446 n
= (*get_config
)(name
, buf
, size
, &error
);
448 mconsole_reply(req
, error
, 1, 0);
453 mconsole_reply(req
, buf
, 0, 0);
457 if (buf
!= default_buf
)
461 buf
= kmalloc(size
, GFP_KERNEL
);
463 mconsole_reply(req
, "Failed to allocate buffer", 1, 0);
468 if (buf
!= default_buf
)
472 void mconsole_config(struct mc_request
*req
)
474 struct mc_device
*dev
;
475 char *ptr
= req
->request
.data
, *name
, *error_string
= "";
478 ptr
+= strlen("config");
479 ptr
= skip_spaces(ptr
);
480 dev
= mconsole_find_dev(ptr
);
482 mconsole_reply(req
, "Bad configuration option", 1, 0);
486 name
= &ptr
[strlen(dev
->name
)];
488 while ((*ptr
!= '=') && (*ptr
!= '\0'))
492 err
= (*dev
->config
)(name
, &error_string
);
493 mconsole_reply(req
, error_string
, err
, 0);
495 else mconsole_get_config(dev
->get_config
, req
, name
);
498 void mconsole_remove(struct mc_request
*req
)
500 struct mc_device
*dev
;
501 char *ptr
= req
->request
.data
, *err_msg
= "";
503 int err
, start
, end
, n
;
505 ptr
+= strlen("remove");
506 ptr
= skip_spaces(ptr
);
507 dev
= mconsole_find_dev(ptr
);
509 mconsole_reply(req
, "Bad remove option", 1, 0);
513 ptr
= &ptr
[strlen(dev
->name
)];
516 n
= (*dev
->id
)(&ptr
, &start
, &end
);
518 err_msg
= "Couldn't parse device number";
521 else if ((n
< start
) || (n
> end
)) {
522 sprintf(error
, "Invalid device number - must be between "
523 "%d and %d", start
, end
);
529 err
= (*dev
->remove
)(n
, &err_msg
);
536 err_msg
= "Device doesn't exist";
540 err_msg
= "Device is currently open";
546 mconsole_reply(req
, err_msg
, err
, 0);
549 struct mconsole_output
{
550 struct list_head list
;
551 struct mc_request
*req
;
554 static DEFINE_SPINLOCK(client_lock
);
555 static LIST_HEAD(clients
);
556 static char console_buf
[MCONSOLE_MAX_DATA
];
558 static void console_write(struct console
*console
, const char *string
,
561 struct list_head
*ele
;
564 if (list_empty(&clients
))
568 n
= min((size_t) len
, ARRAY_SIZE(console_buf
));
569 strncpy(console_buf
, string
, n
);
573 list_for_each(ele
, &clients
) {
574 struct mconsole_output
*entry
;
576 entry
= list_entry(ele
, struct mconsole_output
, list
);
577 mconsole_reply_len(entry
->req
, console_buf
, n
, 0, 1);
582 static struct console mc_console
= { .name
= "mc",
583 .write
= console_write
,
584 .flags
= CON_ENABLED
,
587 static int mc_add_console(void)
589 register_console(&mc_console
);
593 late_initcall(mc_add_console
);
595 static void with_console(struct mc_request
*req
, void (*proc
)(void *),
598 struct mconsole_output entry
;
602 spin_lock_irqsave(&client_lock
, flags
);
603 list_add(&entry
.list
, &clients
);
604 spin_unlock_irqrestore(&client_lock
, flags
);
608 mconsole_reply_len(req
, "", 0, 0, 0);
610 spin_lock_irqsave(&client_lock
, flags
);
611 list_del(&entry
.list
);
612 spin_unlock_irqrestore(&client_lock
, flags
);
615 #ifdef CONFIG_MAGIC_SYSRQ
617 #include <linux/sysrq.h>
619 static void sysrq_proc(void *arg
)
625 void mconsole_sysrq(struct mc_request
*req
)
627 char *ptr
= req
->request
.data
;
629 ptr
+= strlen("sysrq");
630 ptr
= skip_spaces(ptr
);
633 * With 'b', the system will shut down without a chance to reply,
634 * so in this case, we reply first.
637 mconsole_reply(req
, "", 0, 0);
639 with_console(req
, sysrq_proc
, ptr
);
642 void mconsole_sysrq(struct mc_request
*req
)
644 mconsole_reply(req
, "Sysrq not compiled in", 1, 0);
648 static void stack_proc(void *arg
)
650 struct task_struct
*task
= arg
;
652 show_stack(task
, NULL
, KERN_INFO
);
656 * Mconsole stack trace
657 * Added by Allan Graves, Jeff Dike
658 * Dumps a stacks registers to the linux console.
661 void mconsole_stack(struct mc_request
*req
)
663 char *ptr
= req
->request
.data
;
664 int pid_requested
= -1;
665 struct task_struct
*to
= NULL
;
669 * 1) Send showregs output to mconsole.
670 * 2) Add a way to stack dump all pids.
673 ptr
+= strlen("stack");
674 ptr
= skip_spaces(ptr
);
677 * Should really check for multiple pids or reject bad args here
679 /* What do the arguments in mconsole_reply mean? */
680 if (sscanf(ptr
, "%d", &pid_requested
) == 0) {
681 mconsole_reply(req
, "Please specify a pid", 1, 0);
685 to
= find_task_by_pid_ns(pid_requested
, &init_pid_ns
);
686 if ((to
== NULL
) || (pid_requested
== 0)) {
687 mconsole_reply(req
, "Couldn't find that pid", 1, 0);
690 with_console(req
, stack_proc
, to
);
693 static int __init
mount_proc(void)
695 struct file_system_type
*proc_fs_type
;
696 struct vfsmount
*mnt
;
698 proc_fs_type
= get_fs_type("proc");
702 mnt
= kern_mount(proc_fs_type
);
703 put_filesystem(proc_fs_type
);
712 * Changed by mconsole_setup, which is __setup, and called before SMP is
715 static char *notify_socket
= NULL
;
717 static int __init
mconsole_init(void)
719 /* long to avoid size mismatch warnings from gcc */
722 char file
[UNIX_PATH_MAX
];
726 if (umid_file_name("mconsole", file
, sizeof(file
)))
728 snprintf(mconsole_socket_name
, sizeof(file
), "%s", file
);
730 sock
= os_create_unix_socket(file
, sizeof(file
), 1);
732 printk(KERN_ERR
"Failed to initialize management console\n");
735 if (os_set_fd_block(sock
, 0))
738 register_reboot_notifier(&reboot_notifier
);
740 err
= um_request_irq(MCONSOLE_IRQ
, sock
, IRQ_READ
, mconsole_interrupt
,
741 IRQF_SHARED
, "mconsole", (void *)sock
);
743 printk(KERN_ERR
"Failed to get IRQ for management console\n");
747 if (notify_socket
!= NULL
) {
748 notify_socket
= kstrdup(notify_socket
, GFP_KERNEL
);
749 if (notify_socket
!= NULL
)
750 mconsole_notify(notify_socket
, MCONSOLE_SOCKET
,
751 mconsole_socket_name
,
752 strlen(mconsole_socket_name
) + 1);
753 else printk(KERN_ERR
"mconsole_setup failed to strdup "
757 printk(KERN_INFO
"mconsole (version %d) initialized on %s\n",
758 MCONSOLE_VERSION
, mconsole_socket_name
);
766 __initcall(mconsole_init
);
768 static ssize_t
mconsole_proc_write(struct file
*file
,
769 const char __user
*buffer
, size_t count
, loff_t
*pos
)
773 buf
= memdup_user_nul(buffer
, count
);
777 mconsole_notify(notify_socket
, MCONSOLE_USER_NOTIFY
, buf
, count
);
782 static const struct proc_ops mconsole_proc_ops
= {
783 .proc_write
= mconsole_proc_write
,
784 .proc_lseek
= noop_llseek
,
787 static int create_proc_mconsole(void)
789 struct proc_dir_entry
*ent
;
791 if (notify_socket
== NULL
)
794 ent
= proc_create("mconsole", 0200, NULL
, &mconsole_proc_ops
);
796 printk(KERN_INFO
"create_proc_mconsole : proc_create failed\n");
802 static DEFINE_SPINLOCK(notify_spinlock
);
804 void lock_notify(void)
806 spin_lock(¬ify_spinlock
);
809 void unlock_notify(void)
811 spin_unlock(¬ify_spinlock
);
814 __initcall(create_proc_mconsole
);
816 #define NOTIFY "notify:"
818 static int mconsole_setup(char *str
)
820 if (!strncmp(str
, NOTIFY
, strlen(NOTIFY
))) {
821 str
+= strlen(NOTIFY
);
824 else printk(KERN_ERR
"mconsole_setup : Unknown option - '%s'\n", str
);
828 __setup("mconsole=", mconsole_setup
);
830 __uml_help(mconsole_setup
,
831 "mconsole=notify:<socket>\n"
832 " Requests that the mconsole driver send a message to the named Unix\n"
833 " socket containing the name of the mconsole socket. This also serves\n"
834 " to notify outside processes when UML has booted far enough to respond\n"
835 " to mconsole requests.\n\n"
838 static int notify_panic(struct notifier_block
*self
, unsigned long unused1
,
843 if (notify_socket
== NULL
)
846 mconsole_notify(notify_socket
, MCONSOLE_PANIC
, message
,
847 strlen(message
) + 1);
851 static struct notifier_block panic_exit_notifier
= {
852 .notifier_call
= notify_panic
,
857 static int add_notifier(void)
859 atomic_notifier_chain_register(&panic_notifier_list
,
860 &panic_exit_notifier
);
864 __initcall(add_notifier
);
866 char *mconsole_notify_socket(void)
868 return notify_socket
;
871 EXPORT_SYMBOL(mconsole_notify_socket
);