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Subject[Suspend2][ 11/21] [Suspend2] Wait for keypress.
Date
Wait for a keypress. This might be via userspace (normal case), or in the
special case of an emergency message early in the process, via reading
/dev/console. In these later cases, we can't rely on the userspace process
existing, and want to give the user some control over what happens. We do
implement a timeout though, so unattended boots don't hang indefinitely.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

kernel/power/ui.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/kernel/power/ui.c b/kernel/power/ui.c
index 3378766..6271a24 100644
--- a/kernel/power/ui.c
+++ b/kernel/power/ui.c
@@ -331,3 +331,74 @@ void __suspend_message(unsigned long sec
&msg, sizeof(msg));
}

+static void wait_for_key_via_userui(void)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ add_wait_queue(&userui_wait_for_key, &wait);
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ interruptible_sleep_on(&userui_wait_for_key);
+
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&userui_wait_for_key, &wait);
+}
+
+char suspend_wait_for_keypress(int timeout)
+{
+ int fd;
+ char key = '\0';
+ struct termios t, t_backup;
+
+ if (ui_helper_data.pid != -1) {
+ wait_for_key_via_userui();
+ key = ' ';
+ goto out;
+ }
+
+ /* We should be guaranteed /dev/console exists after populate_rootfs() in
+ * init/main.c
+ */
+ if ((fd = sys_open("/dev/console", O_RDONLY, 0)) < 0) {
+ printk("Couldn't open /dev/console.\n");
+ goto out;
+ }
+
+ if (sys_ioctl(fd, TCGETS, (long)&t) < 0)
+ goto out_close;
+
+ memcpy(&t_backup, &t, sizeof(t));
+
+ t.c_lflag &= ~(ISIG|ICANON|ECHO);
+ t.c_cc[VMIN] = 0;
+ if (timeout)
+ t.c_cc[VTIME] = timeout*10;
+
+ if (sys_ioctl(fd, TCSETS, (long)&t) < 0)
+ goto out_restore;
+
+ while (1) {
+ if (sys_read(fd, &key, 1) <= 0) {
+ key = '\0';
+ break;
+ }
+ key = tolower(key);
+ if (test_suspend_state(SUSPEND_SANITY_CHECK_PROMPT)) {
+ if (key == 'c') {
+ set_suspend_state(SUSPEND_CONTINUE_REQ);
+ break;
+ } else if (key == ' ')
+ break;
+ } else
+ break;
+ }
+
+out_restore:
+ sys_ioctl(fd, TCSETS, (long)&t_backup);
+
+out_close:
+ sys_close(fd);
+out:
+ return key;
+}
+
--
Nigel Cunningham nigel at suspend2 dot net
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