Merge pull request #963 from cyberbotics/sync-master-3485871c10f5f5ae…

…e8b99b49d27624ba98885380

Sync libcontroller master

webots_ros2_driver/webots/src/controller/c/robot.c

@@ -1081,21 +1081,33 @@ static void wb_robot_cleanup_devices() {
   }
 }
 
-static char *encode_robot_name(const char *robot_name) {
+static char *encode_robot_name(const char *robot_name, int chars_used) {
   if (!robot_name)
     return NULL;
 
   char *encoded_name = percent_encode(robot_name);
   int length = strlen(encoded_name);
   // the robot name is used to connect to the libController and in this process there are indirect
-  // limitations such as QLocalServer only accepting strings up to 106 characters for server names,
-  // for these reasons if the robot name is bigger than an arbitrary length, a hashed version is used instead
-  if (length > 70) {  // note: this threshold should be the same as in WbRobot.cpp
+  // limitations such as QLocalServer only accepting strings up to 91 characters long for server names
+  // on some platforms.
+  // Since the server name also contains the tmp path and that includes the user's username and,
+  // in the case of a Snap, the user's home directory, we need to limit the length of the encoded
+  // robot name based on the tmp path. If it is longer than that, then we compute a hashed version
+  // of the name and use as much of it as we can. If that would be less than 4 chars, we try to use
+  // 4 chars and hope we are on a platform where QLocalServer accepts longer names. 4 chars makes the
+  // chance of a name collision 1/65536.
+  // Note: It is critical that the same logic is used in WbRobot.cpp
+  int max_name_length = 91 - chars_used;
+  if (max_name_length < 4)
+    max_name_length = 4;
+  // Round down to the next multiple of 2 because it makes the code easier.
+  max_name_length = max_name_length / 2 * 2;
+  if (length > max_name_length) {
     char hash[21];
-    char *output = malloc(41);
+    char *output = malloc(max_name_length + 1);
     SHA1(hash, encoded_name, length);
     free(encoded_name);
-    for (size_t i = 0; i < 20; i++)
+    for (size_t i = 0; i < max_name_length / 2 && i < 20; i++)
       sprintf((output + (2 * i)), "%02x", hash[i] & 0xff);
     return output;
   }
@@ -1104,10 +1116,12 @@ static char *encode_robot_name(const char *robot_name) {
 }
 
 static char *compute_socket_filename(char *error_buffer) {
-  char *robot_name = encode_robot_name(wbu_system_getenv("WEBOTS_ROBOT_NAME"));
   const char *WEBOTS_INSTANCE_PATH = wbu_system_webots_instance_path(true);
+  char *robot_name = NULL;
+  const char *WEBOTS_ROBOT_NAME = wbu_system_getenv("WEBOTS_ROBOT_NAME");
   char *socket_filename;
-  if (robot_name && robot_name[0] && WEBOTS_INSTANCE_PATH && WEBOTS_INSTANCE_PATH[0]) {
+  if (WEBOTS_ROBOT_NAME && WEBOTS_ROBOT_NAME[0] && WEBOTS_INSTANCE_PATH && WEBOTS_INSTANCE_PATH[0]) {
+    robot_name = encode_robot_name(WEBOTS_ROBOT_NAME, strlen(WEBOTS_INSTANCE_PATH) + strlen("ipc//intern"));
 #ifndef _WIN32
     const int length = strlen(WEBOTS_INSTANCE_PATH) + strlen(robot_name) + 15;  // "%sintern/%s/socket"
     socket_filename = malloc(length);
@@ -1267,7 +1281,7 @@ static char *compute_socket_filename(char *error_buffer) {
 
   free(robot_name);
   const char *sub_string = strstr(&WEBOTS_CONTROLLER_URL[6], "/");
-  robot_name = encode_robot_name(sub_string ? sub_string + 1 : NULL);
+  robot_name = encode_robot_name(sub_string ? sub_string + 1 : NULL, strlen(ipc_folder) + strlen("//extern"));
   if (robot_name) {
 #ifndef _WIN32
     // socket file name is like: folder + robot_name + "/extern"
@@ -1370,7 +1384,7 @@ static void compute_remote_info(char **host, int *port, char **robot_name) {
   snprintf(*host, host_length, "%s", &WEBOTS_CONTROLLER_URL[6]);
   sscanf(url_suffix, ":%d", port);
   const char *rn = strstr(url_suffix, "/");
-  *robot_name = rn != NULL ? encode_robot_name(rn + 1) : NULL;
+  *robot_name = rn != NULL ? encode_robot_name(rn + 1, 0) : NULL;
 }
 
 int wb_robot_init() {  // API initialization
@@ -1462,11 +1476,11 @@ int wb_robot_init() {  // API initialization
         retry -= 5;
         fprintf(stderr, "%s, pending until loading is done...\n", error_message);
       } else if (socket_filename) {
+        fprintf(stderr,
+                "The specified robot (at %s) is not in the list of robots with <extern> controllers, retrying for another %d "
+                "seconds...\n",
+                socket_filename, 50 - retry);
         free(socket_filename);
-        fprintf(
-          stderr,
-          "The specified robot is not in the list of robots with <extern> controllers, retrying for another %d seconds...\n",
-          50 - retry);
       } else
         fprintf(stderr, "%s, retrying for another %d seconds...\n", error_message, 50 - retry);
     }