Initial commit

1 files changed, 122 insertions, 0 deletions

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..faf15b0
--- /dev/null
+++ b/main.c
@@ -0,0 +1,122 @@
+#include <linux/uinput.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <signal.h>
+
+bool should_stop = false;
+
+void sigint_handler(int _value)
+{
+    (void) _value;
+    should_stop = true;
+    printf("SIGINT handled\n");
+}
+
+void emit(int fd, int type, int code, int val)
+{
+    struct input_event ie;
+
+    ie.type = type;
+    ie.code = code;
+    ie.value = val;
+    /* timestamp values below are ignored */
+    ie.time.tv_sec = 0;
+    ie.time.tv_usec = 0;
+
+    write(fd, &ie, sizeof(ie));
+}
+
+int main(int argc, char *argv[])
+{
+    if (argc < 2) {
+        fprintf(stderr, "Error: No input device specified\n");
+        exit(1);
+    }
+    const char *input_path = argv[1];
+    int ifd = open(input_path, O_RDONLY);
+    if (ifd == -1) {
+        fprintf(stderr, "\"%s\": ", input_path);
+        perror("open");
+        exit(1);
+    }
+    int ofd = open("/dev/uinput", O_WRONLY);
+    if (ofd == -1) {
+        fprintf(stderr, "\"/dev/uinput\": ");
+        perror("open");
+        exit(1);
+    }
+    signal(SIGINT, sigint_handler);
+
+    /*
+     * The ioctls below will enable the device that is about to be
+     * created, to pass key events, in this case the space key.
+     */
+    ioctl(ofd, UI_SET_EVBIT, EV_KEY);
+    ioctl(ofd, UI_SET_KEYBIT, KEY_SPACE);
+
+    struct uinput_setup usetup;
+    memset(&usetup, 0, sizeof(usetup));
+    usetup.id.bustype = BUS_USB;
+    usetup.id.vendor = 0x1234; /* sample vendor */
+    usetup.id.product = 0x5678; /* sample product */
+    strcpy(usetup.name, "Example device");
+
+    ioctl(ofd, UI_DEV_SETUP, &usetup);
+    ioctl(ofd, UI_DEV_CREATE);
+
+    /*
+     * On UI_DEV_CREATE the kernel will create the device node for this
+     * device. We are inserting a pause here so that userspace has time
+     * to detect, initialize the new device, and can start listening to
+     * the event, otherwise it will not notice the event we are about
+     * to send. This pause is only needed in our example code!
+     */
+    sleep(1);
+
+    while (!should_stop) {
+        struct input_event ev;
+        ssize_t ret = read(ifd, &ev, sizeof(ev));
+        switch (ev.type) {
+        case EV_KEY:
+            printf("EV_KEY, code=%u, value=%d\n", ev.code, ev.value);
+            break;
+        case EV_ABS:
+            /*
+             * d-pad is EV_ABS
+             * left-right: code ABS_HAT0X, left=-1, right=1
+             * down-up: code ABS_HAT0Y, up=-1, down=1
+             */
+            if (ev.code == ABS_HAT0X || ev.code == ABS_HAT0Y) {
+                printf("type=%u, code=%u, value=%d\n", ev.type, ev.code, ev.value);
+            }
+            break;
+        case EV_SYN:
+            break;
+        default:
+            printf("type=%u, code=%u, value=%d\n", ev.type, ev.code, ev.value);
+            break;
+        }
+    }
+
+    /* Key press, report the event, send key release, and report again */
+    emit(ofd, EV_KEY, KEY_SPACE, 1);
+    emit(ofd, EV_SYN, SYN_REPORT, 0);
+    emit(ofd, EV_KEY, KEY_SPACE, 0);
+    emit(ofd, EV_SYN, SYN_REPORT, 0);
+
+    /*
+     * Give userspace some time to read the events before we destroy the
+     * device with UI_DEV_DESTOY.
+     */
+    sleep(1);
+
+    ioctl(ofd, UI_DEV_DESTROY);
+    close(ofd);
+
+    return 0;
+}