Add ugly support for OnePlus alert slider (tested on OP Nord2)

cmds/Android.bp

@@ -253,3 +253,13 @@ cc_binary {
 		"libhidlbase",
 	],
 }
+
+cc_binary {
+	name: "oplus-alert-slider",
+	srcs: [
+		"oplus-alert-slider.cpp",
+	],
+	init_rc: [
+		"oplus-alert-slider.rc",
+	],
+}

cmds/oplus-alert-slider.cpp

@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <linux/input.h>
+
+int read_tristate() {
+    int fd = open("/proc/tristatekey/tri_state", O_RDONLY);
+    char p[16];
+    int ret = read(fd, p, sizeof(p) - 1);
+    p[ret] = 0;
+    return atoi(p);
+}
+
+int main() {
+    int fd = -1;
+    for(int i=0; i<255; i++) {
+        char path[256];
+        snprintf(path, 256, "/dev/input/event%d", i);
+        fd = open(path, O_RDWR);
+        if(fd == -1) continue;
+        char name[256];
+        ioctl(fd, EVIOCGNAME(256), name);
+        printf("Got input name %s\n", name);
+        if(strcmp(name, "oplus,hall_tri_state_key") == 0) {
+            break;
+        }
+        close(fd);
+        fd = -1;
+    }
+    if(fd == -1) return 0;
+
+    ioctl(fd, EVIOCGRAB, 1);
+
+    struct input_event ev;
+    while(read(fd, &ev, sizeof(ev)) != 0) {
+        if(!(ev.code == 61 && ev.value == 0)) continue;
+        int state = read_tristate();
+        if(state == 1) {
+        }
+        printf("State %d\n", read_tristate());
+        if(state == 1) {
+            system("service call audio 31 i32 2 s16 android");
+        } else if(state == 2) {
+            system("service call audio 31 i32 1 s16 android");
+        } else if(state == 3) {
+            system("service call audio 31 i32 0 s16 android");
+        }
+    }
+}

cmds/oplus-alert-slider.rc

@@ -0,0 +1,3 @@
+service phhoplus-alert-slider /system/bin/oplus-alert-slider
+    seclabel u:r:phhsu_daemon:s0
+    class main