Use a different server path for each session

When scrcpy is run, a server is pushed to
/data/local/tmp/scrcpy-server.jar.

Running simultaneous scrcpy instances on the same device was not a
problem, because the file was unlinked (removed) almost immediately once
it started, avoiding any conflicts.

In order to support executing new process using the scrcpy-server.jar at
any time (to change the display power mode from a separate process), the
server file must not be unlinked, so using different names are necessary
to avoid conflicts.

Reuse the scid mechanism already used for generating device socket
names.

Refs 4315be1648
Refs 439a1fd4ed

app/src/server.c

@@ -18,7 +18,6 @@
 #define SC_SERVER_FILENAME "scrcpy-server"
 
 #define SC_SERVER_PATH_DEFAULT PREFIX "/share/scrcpy/" SC_SERVER_FILENAME
-#define SC_DEVICE_SERVER_PATH "/data/local/tmp/scrcpy-server.jar"
 
 #define SC_ADB_PORT_DEFAULT 5555
 #define SC_SOCKET_NAME_PREFIX "scrcpy_"
@@ -117,7 +116,7 @@ error:
 }
 
 static bool
-push_server(struct sc_intr *intr, const char *serial) {
+push_server(struct sc_intr *intr, uint32_t scid, const char *serial) {
     char *server_path = get_server_path();
     if (!server_path) {
         return false;
@@ -127,7 +126,16 @@ push_server(struct sc_intr *intr, const char *serial) {
         free(server_path);
         return false;
     }
-    bool ok = sc_adb_push(intr, serial, server_path, SC_DEVICE_SERVER_PATH, 0);
+
+    char *device_server_path;
+    if (asprintf(&device_server_path, "/data/local/tmp/scrcpy-server-%08x.jar",
+                 scid) == -1) {
+        LOG_OOM();
+        free(server_path);
+        return false;
+    }
+    bool ok = sc_adb_push(intr, serial, server_path, device_server_path, 0);
+    free(device_server_path);
     free(server_path);
     return ok;
 }
@@ -209,13 +217,20 @@ execute_server(struct sc_server *server,
     const char *serial = server->serial;
     assert(serial);
 
+    char *classpath;
+    if (asprintf(&classpath, "CLASSPATH=/data/local/tmp/scrcpy-server-%08x.jar",
+                 params->scid) == -1) {
+        LOG_OOM();
+        return SC_PROCESS_NONE;
+    }
+
     const char *cmd[128];
     unsigned count = 0;
     cmd[count++] = sc_adb_get_executable();
     cmd[count++] = "-s";
     cmd[count++] = serial;
     cmd[count++] = "shell";
-    cmd[count++] = "CLASSPATH=" SC_DEVICE_SERVER_PATH;
+    cmd[count++] = classpath;
     cmd[count++] = "app_process";
 
 #ifdef SERVER_DEBUGGER
@@ -388,6 +403,7 @@ end:
     for (unsigned i = dyn_idx; i < count; ++i) {
         free((char *) cmd[i]);
     }
+    free(classpath);
 
     return pid;
 }
@@ -937,7 +953,7 @@ run_server(void *data) {
     assert(serial);
     LOGD("Device serial: %s", serial);
 
-    ok = push_server(&server->intr, serial);
+    ok = push_server(&server->intr, params->scid, serial);
     if (!ok) {
         goto error_connection_failed;
     }