projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 3e2b8fbe JF |
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. */ | |
| 22 | static int shutting_down = SHUTDOWN_INVALID; | |
| 23 | ||
| 24 | static 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 | ||
| 67 | static 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 | ||
| 96 | static struct xenbus_watch shutdown_watch = { | |
| 97 | .node = "control/shutdown", | |
| 98 | .callback = shutdown_handler | |
| 99 | }; | |
| 100 | ||
| 101 | static struct xenbus_watch sysrq_watch = { | |
| 102 | .node = "control/sysrq", | |
| 103 | .callback = sysrq_handler | |
| 104 | }; | |
| 105 | ||
| 106 | static 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 | ||
| 125 | static 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 | ||
| 133 | static 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 | ||
| 143 | subsys_initcall(setup_shutdown_event); |