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review.evervolv.com / android_kernel_htc_msm8960 / b9ec0339d8e22cadf2d9d1b010b51dc53837dfb0 / . / arch / x86 / xen / manage.c
blob: aa7af9e6abc05ac622da6930ab87e8f731f802bd [file] [log] [blame]
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -0700[diff] [blame]1/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4#include <linux/kernel.h>
5#include <linux/err.h>
6#include <linux/reboot.h>
7#include <linux/sysrq.h>
8
9#include <xen/xenbus.h>
10
11#define SHUTDOWN_INVALID -1
12#define SHUTDOWN_POWEROFF 0
13#define SHUTDOWN_SUSPEND 2
14/* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
15 * report a crash, not be instructed to crash!
16 * HALT is the same as POWEROFF, as far as we're concerned. The tools use
17 * the distinction when we return the reason code to them.
18 */
19#define SHUTDOWN_HALT 4
20
21/* Ignore multiple shutdown requests. */
22static int shutting_down = SHUTDOWN_INVALID;
23
24static void shutdown_handler(struct xenbus_watch *watch,
25 const char **vec, unsigned int len)
26{
27 char *str;
28 struct xenbus_transaction xbt;
29 int err;
30
31 if (shutting_down != SHUTDOWN_INVALID)
32 return;
33
34 again:
35 err = xenbus_transaction_start(&xbt);
36 if (err)
37 return;
38
39 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
40 /* Ignore read errors and empty reads. */
41 if (XENBUS_IS_ERR_READ(str)) {
42 xenbus_transaction_end(xbt, 1);
43 return;
44 }
45
46 xenbus_write(xbt, "control", "shutdown", "");
47
48 err = xenbus_transaction_end(xbt, 0);
49 if (err == -EAGAIN) {
50 kfree(str);
51 goto again;
52 }
53
54 if (strcmp(str, "poweroff") == 0 ||
55 strcmp(str, "halt") == 0)
56 orderly_poweroff(false);
57 else if (strcmp(str, "reboot") == 0)
58 ctrl_alt_del();
59 else {
60 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
61 shutting_down = SHUTDOWN_INVALID;
62 }
63
64 kfree(str);
65}
66
67static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
68 unsigned int len)
69{
70 char sysrq_key = '\0';
71 struct xenbus_transaction xbt;
72 int err;
73
74 again:
75 err = xenbus_transaction_start(&xbt);
76 if (err)
77 return;
78 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
79 printk(KERN_ERR "Unable to read sysrq code in "
80 "control/sysrq\n");
81 xenbus_transaction_end(xbt, 1);
82 return;
83 }
84
85 if (sysrq_key != '\0')
86 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
87
88 err = xenbus_transaction_end(xbt, 0);
89 if (err == -EAGAIN)
90 goto again;
91
92 if (sysrq_key != '\0')
93 handle_sysrq(sysrq_key, NULL);
94}
95
96static struct xenbus_watch shutdown_watch = {
97 .node = "control/shutdown",
98 .callback = shutdown_handler
99};
100
101static struct xenbus_watch sysrq_watch = {
102 .node = "control/sysrq",
103 .callback = sysrq_handler
104};
105
106static int setup_shutdown_watcher(void)
107{
108 int err;
109
110 err = register_xenbus_watch(&shutdown_watch);
111 if (err) {
112 printk(KERN_ERR "Failed to set shutdown watcher\n");
113 return err;
114 }
115
116 err = register_xenbus_watch(&sysrq_watch);
117 if (err) {
118 printk(KERN_ERR "Failed to set sysrq watcher\n");
119 return err;
120 }
121
122 return 0;
123}
124
125static int shutdown_event(struct notifier_block *notifier,
126 unsigned long event,
127 void *data)
128{
129 setup_shutdown_watcher();
130 return NOTIFY_DONE;
131}
132
133static int __init setup_shutdown_event(void)
134{
135 static struct notifier_block xenstore_notifier = {
136 .notifier_call = shutdown_event
137 };
138 register_xenstore_notifier(&xenstore_notifier);
139
140 return 0;
141}
142
143subsys_initcall(setup_shutdown_event);