Add vibrate

README.md

@@ -35,6 +35,20 @@ $ pptk-cpu-sleep get
 disabled
 ```
 
+### vibrate
+Controls the vibrator to play a vibration pattern.
+```
+# vibrate for 1 second
+$ pptk-vibrate 1000
+
+# vibrate for 500 ms, wait for 500 ms, repeat this pattern 5 times
+# resulting in an alternating vibration for 5 seconds in total
+$ pptk-vibrate 500 500 5
+
+# 6 short vibrations followed by 3 long vibrations
+$ pptk-vibrate 300 200 6 && pptk-vibrate 1500 500 3
+```
+
 ## Build & Install
 ```
 $ meson build

meson.build

@@ -6,3 +6,5 @@ executable('pptk-led', ['src/led.c'],
   install: true, install_mode: install_suid)
 executable('pptk-cpu-sleep', ['src/cpu-sleep.c'],
   install: true, install_mode: install_suid)
+executable('pptk-vibrate', ['src/vibrate.c'],
+  install: true, install_mode: install_suid)

src/vibrate.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <linux/input.h>
+
+static char *argv0 = "./vibrate";
+static char *vibrator_file = "/dev/input/event4";
+
+void print_usage()
+{
+    printf("usage: %s LENGTH [DELAY] [COUNT]\n", argv0);
+    printf("  LENGTH = [0..] ... duration of vibration (in ms)\n");
+    printf("  DELAY = [0..]  ... delay before vibration is repeated (in ms)\n");
+    printf("  COUNT = [1..]  ... how many times the vibration pattern is to be repeated\n");
+}
+
+void print_usage_and_fail()
+{
+    print_usage();
+    exit(EXIT_FAILURE);
+}
+
+void assert(bool success, char* error_message)
+{
+    if (success) {
+        return;
+    }
+    fprintf(stderr, "%s\n", error_message);
+    exit(EXIT_FAILURE);
+}
+
+void write_event(int fd, int e_id, int value)
+{
+    struct input_event event;
+    memset(&event, 0, sizeof(event));
+    event.type = EV_FF;
+    event.code = e_id;
+    event.value = value;
+    int res = write(fd, &event, sizeof event);
+    assert(res >= 0, "write event failed");
+}
+
+void vibrate(int length, int delay, int repeat)
+{
+    int res;
+    
+    res = setuid(0);
+    assert(res == 0, "Cannot set root permissions via setuid(0).");
+
+    int fd = open(vibrator_file, O_RDWR | O_CLOEXEC);
+    if (fd < 0) {
+        fprintf(stderr, "Cannot open file '%s' for writing.\n", vibrator_file);
+        exit(EXIT_FAILURE);
+    }
+
+    int effects;
+    res = ioctl(fd, EVIOCGEFFECTS, &effects);
+    assert(res >= 0, "ioctl(EVIOCGEFFECTS) failed");
+    assert(effects > 0, "not enough simultaneous effects supported");
+
+    /* upload rumble effect */
+    struct ff_effect e;
+    memset(&e, 0, sizeof(e));
+    e.type = FF_RUMBLE,
+    e.id = -1;
+    e.replay.length = length;
+    e.replay.delay = delay;
+    e.u.rumble.strong_magnitude = 0xc000;
+    e.u.rumble.weak_magnitude = 0;
+    res = ioctl(fd, EVIOCSFF, &e);
+    assert(res >= 0, "ioctl(EVIOCSFF) failed");
+
+    /* play vibration pattern */
+    write_event(fd, e.id, repeat);
+    usleep((length + delay) * repeat * 1000);
+    write_event(fd, e.id, 0);
+
+    /* clear rumble effect */
+    res = ioctl(fd, EVIOCRMFF, e.id);
+    assert(res >= 0, "ioctl(EVIOCRMFF) failed");
+
+    close(fd);
+}
+
+int main(int argc, char *argv[])
+{
+    if (argc < 1) {
+        print_usage_and_fail();
+    }
+    argv0 = argv[0];
+    if (argc < 2) {
+        print_usage_and_fail();
+    }
+    int length = atoi(argv[1]);
+    int delay = argc < 3 ? 0 : atoi(argv[2]);
+    int repeat = argc < 4 ? 1 : atoi(argv[3]);
+    if (length < 0 || delay < 0 || repeat <= 0) {
+        print_usage_and_fail();
+    }
+    //printf("vibrate %d ms, wait %d ms, repeat %d\n", length, delay, repeat);
+    vibrate(length, delay, repeat);
+    exit(EXIT_SUCCESS);
+}