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3e2b8fbeec
The guest domain can be asked to shutdown or reboot itself, or have a sysrq key injected, via xenbus. This patch adds a watcher for those events, and does the appropriate action. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Chris Wright <chrisw@sous-sol.org>
144 lines
3.0 KiB
C
144 lines
3.0 KiB
C
/*
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* Handle extern requests for shutdown, reboot and sysrq
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*/
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/reboot.h>
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#include <linux/sysrq.h>
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#include <xen/xenbus.h>
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#define SHUTDOWN_INVALID -1
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#define SHUTDOWN_POWEROFF 0
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#define SHUTDOWN_SUSPEND 2
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/* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
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* report a crash, not be instructed to crash!
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* HALT is the same as POWEROFF, as far as we're concerned. The tools use
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* the distinction when we return the reason code to them.
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*/
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#define SHUTDOWN_HALT 4
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/* Ignore multiple shutdown requests. */
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static int shutting_down = SHUTDOWN_INVALID;
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static void shutdown_handler(struct xenbus_watch *watch,
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const char **vec, unsigned int len)
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{
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char *str;
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struct xenbus_transaction xbt;
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int err;
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if (shutting_down != SHUTDOWN_INVALID)
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return;
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again:
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err = xenbus_transaction_start(&xbt);
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if (err)
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return;
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str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
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/* Ignore read errors and empty reads. */
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if (XENBUS_IS_ERR_READ(str)) {
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xenbus_transaction_end(xbt, 1);
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return;
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}
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xenbus_write(xbt, "control", "shutdown", "");
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err = xenbus_transaction_end(xbt, 0);
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if (err == -EAGAIN) {
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kfree(str);
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goto again;
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}
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if (strcmp(str, "poweroff") == 0 ||
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strcmp(str, "halt") == 0)
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orderly_poweroff(false);
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else if (strcmp(str, "reboot") == 0)
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ctrl_alt_del();
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else {
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printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
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shutting_down = SHUTDOWN_INVALID;
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}
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kfree(str);
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}
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static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
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unsigned int len)
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{
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char sysrq_key = '\0';
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struct xenbus_transaction xbt;
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int err;
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again:
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err = xenbus_transaction_start(&xbt);
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if (err)
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return;
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if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
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printk(KERN_ERR "Unable to read sysrq code in "
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"control/sysrq\n");
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xenbus_transaction_end(xbt, 1);
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return;
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}
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if (sysrq_key != '\0')
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xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
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err = xenbus_transaction_end(xbt, 0);
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if (err == -EAGAIN)
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goto again;
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if (sysrq_key != '\0')
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handle_sysrq(sysrq_key, NULL);
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}
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static struct xenbus_watch shutdown_watch = {
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.node = "control/shutdown",
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.callback = shutdown_handler
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};
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static struct xenbus_watch sysrq_watch = {
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.node = "control/sysrq",
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.callback = sysrq_handler
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};
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static int setup_shutdown_watcher(void)
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{
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int err;
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err = register_xenbus_watch(&shutdown_watch);
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if (err) {
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printk(KERN_ERR "Failed to set shutdown watcher\n");
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return err;
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}
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err = register_xenbus_watch(&sysrq_watch);
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if (err) {
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printk(KERN_ERR "Failed to set sysrq watcher\n");
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return err;
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}
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return 0;
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}
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static int shutdown_event(struct notifier_block *notifier,
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unsigned long event,
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void *data)
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{
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setup_shutdown_watcher();
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return NOTIFY_DONE;
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}
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static int __init setup_shutdown_event(void)
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{
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static struct notifier_block xenstore_notifier = {
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.notifier_call = shutdown_event
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};
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register_xenstore_notifier(&xenstore_notifier);
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return 0;
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}
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subsys_initcall(setup_shutdown_event);
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