implements a function to restart the daemon by command or signal

Because sometimes tho communication between daemon and KB is corrupted
after resuming from Standby or suspend, a restart function is
implemented.
It first calls the quit() funtion, then it calls main() again with the
original parameter list.

There are two ways to restart the daemon:
- send the string "restart some-description-as-one-word" to the cmd-pipe
  (normally /dev/input/ckb1/cmd or /dev/input/ckb2/cmd, dependign on
  what device gets what usb number

- sending SIGUSR1 to the daemon-process (as root).

Later on, there may be a user interface in the client
for the first method.

DAEMON.md

@@ -203,6 +203,18 @@ The latest firmware versions and their URLs can be found in the `FIRMWARE` docum
 
 When the device reconnects you should see the new firmware version in its `fwversion` node; if you see `0000` instead it means that the keyboard did not update successfully and will need another `fwupdate` command in order to function again. If the update fails repeatedly, try connecting the keyboard to a Windows PC and using the official firmware update in CUE.
 
+Restart
+-------
+
+Because sometimes tho communication between daemon and KB is corrupted after resuming from Standby or suspend, a restart function is implemented.
+It first calls the quit() funtion, then it calls main() again with the original parameter list.
+
+There are two ways to restart the daemon:
+- send the string "restart some-description-as-one-word" to the cmd-pipe (normally /dev/input/ckb1/cmd or /dev/input/ckb2/cmd, dependign on what device gets what usb number
+- sending SIGUSR1 to the daemon-process (as root).
+
+Later on, there may be a user interface in the client for the first method.
+
 Security
 --------
 

src/ckb-daemon/command.c

@@ -51,7 +51,8 @@ static const char* const cmd_strings[CMD_COUNT - 1] = {
 
     "notify",
     "inotify",
-    "get"
+    "get",
+    "restart"
 };
 
 #define TRY_WITH_RESET(action)  \
@@ -276,6 +277,9 @@ int readcmd(usbdevice* kb, const char* line){
                 continue;
             }
             break;
+        case RESTART:
+            vt->do_cmd[command](kb, mode, notifynumber, 0, word);
+            break;
         default:;
         }
         // For anything else, split the parameter at the colon

src/ckb-daemon/command.h

@@ -58,14 +58,15 @@ typedef enum {
     NOTIFY,
     INOTIFY,
     GET,
+    RESTART,
 
-    CMD_LAST = GET
+    CMD_LAST = RESTART
 } cmd;
 #define CMD_COUNT       (CMD_LAST - CMD_FIRST + 2)
 #define CMD_DEV_COUNT   (CMD_LAST - CMD_VT_FIRST + 1)
 
 // Device command vtable. Most have a standard prototype, but a few are exceptions.
-// Not all parameters are used by all commands - they are sometimes repurposed or used as dummy arguemnts. See relevant headers.
+// Not all parameters are used by all commands - they are sometimes repurposed or used as dummy arguments. See relevant headers.
 typedef void (*cmdhandler)(usbdevice* kb, usbmode* modeidx, int notifyidx, int keyindex, const char* parameter);    // Normal command
 typedef int (*cmdhandler_io)(usbdevice* kb, usbmode* modeidx, int notifyidx, int keyindex, const char* parameter);  // Command with hardware I/O - returns zero on success
 typedef void (*cmdhandler_mac)(usbdevice* kb, usbmode* modeidx, int notifyidx, const char* keys, const char* assignment); // Macro command has a different left-side handler
@@ -117,6 +118,7 @@ typedef union devcmd {
         cmdhandler notify;
         cmdhandler inotify;
         cmdhandler get;
+        cmdhandler restart;
 
         // Extra functions not command-related
         // device.h

src/ckb-daemon/device_vtable.c

@@ -59,6 +59,7 @@ const devcmd vtable_keyboard = {
     .notify = cmd_notify,
     .inotify = cmd_inotify,
     .get = cmd_get,
+    .restart = cmd_restart,
 
     .start = start_dev,
     .setmodeindex = int1_void_none,
@@ -105,6 +106,7 @@ const devcmd vtable_keyboard_nonrgb = {
     .notify = cmd_notify,
     .inotify = cmd_inotify,
     .get = cmd_get,
+    .restart = cmd_restart,
 
     .start = start_kb_nrgb,
     .setmodeindex = setmodeindex_nrgb,
@@ -151,6 +153,7 @@ const devcmd vtable_mouse = {
     .notify = cmd_notify,
     .inotify = cmd_none,
     .get = cmd_get,
+    .restart = cmd_restart,
 
     .start = start_dev,
     .setmodeindex = int1_void_none,

src/ckb-daemon/main.c

@@ -4,11 +4,16 @@
 #include "led.h"
 #include "notify.h"
 
+static int main_ac;
+static char **main_av;
+
 // usb.c
 extern volatile int reset_stop;
 extern int features_mask;
 // device.c
 extern int hwload_mode;
+static void quit2(char mut);
+extern int restart();
 
 // Timespec utility function
 void timespec_add(struct timespec* timespec, long nanoseconds){
@@ -17,12 +22,18 @@ void timespec_add(struct timespec* timespec, long nanoseconds){
     timespec->tv_nsec = nanoseconds % 1000000000;
 }
 
-void quit(){
+static void quit(){
+    quit2(1);
+}
+
+// try to close files maybe without locking the mutex
+// if mut == true then lock
+void quit2(char mut){
     // Abort any USB resets in progress
     reset_stop = 1;
     for(int i = 1; i < DEV_MAX; i++){
         // Before closing, set all keyboards back to HID input mode so that the stock driver can still talk to them
-        pthread_mutex_lock(devmutex + i);
+        if (mut) pthread_mutex_lock(devmutex + i);
         if(IS_CONNECTED(keyboard + i)){
             revertusb(keyboard + i);
             closeusb(keyboard + i);
@@ -69,6 +80,8 @@ int main(int argc, char** argv){
     // Set output pipes to buffer on newlines, if they weren't set that way already
     setlinebuf(stdout);
     setlinebuf(stderr);
+    main_ac = argc;
+    main_av = argv;
 
     printf("    ckb: Corsair RGB driver %s\n", CKB_VERSION_STR);
     // If --help occurs anywhere in the command-line, don't launch the program but instead print usage
@@ -189,14 +202,22 @@ int main(int argc, char** argv){
     sigdelset(&signals, SIGTERM);
     sigdelset(&signals, SIGINT);
     sigdelset(&signals, SIGQUIT);
+    sigdelset(&signals, SIGUSR1);
     // Set up signal handlers for quitting the service.
     sigprocmask(SIG_SETMASK, &signals, 0);
     signal(SIGTERM, sighandler);
     signal(SIGINT, sighandler);
     signal(SIGQUIT, sighandler);
+    signal(SIGUSR1, (void (*)())restart);
 
     // Start the USB system
     int result = usbmain();
     quit();
     return result;
 }
+
+int restart() {
+    ckb_err("restart called, running quit without mutex-lock.\n");
+    quit2(0);
+    return main(main_ac, main_av);
+}

src/ckb-daemon/notify.c

@@ -217,3 +217,11 @@ void cmd_get(usbdevice* kb, usbmode* mode, int nnumber, int dummy, const char* s
     _cmd_get(kb, mode, nnumber, setting);
     pthread_mutex_unlock(imutex(kb));
 }
+
+extern int restart();
+
+void cmd_restart(usbdevice* kb, usbmode* mode, int nnumber, int dummy, const char* content) {
+    ckb_info("RESTART called with %s\n", content);
+    nprintf(kb, -1, 0, "RESTART called with %s\n", content);
+    restart();
+}

src/ckb-daemon/notify.h

@@ -24,4 +24,8 @@ void cmd_notify(usbdevice* kb, usbmode* mode, int nnumber, int keyindex, const c
 // MUTEXES: Locks imutex during operation. Unlocks on close.
 void cmd_get(usbdevice* kb, usbmode* mode, int nnumber, int dummy, const char* setting);
 
+// Just for debugging puposes. Should echo the given string to stderr ([I]) and all open notify channels.
+// At last it does a restart of the daemon
+void cmd_restart(usbdevice* kb, usbmode* mode, int nnumber, int dummy, const char* content);
+
 #endif  // NOTIFY_H