SITL: allow extra arguments to be passed to last_letter

libraries/SITL/SIM_last_letter.cpp

@@ -30,10 +30,11 @@ extern const AP_HAL::HAL& hal;
 /*
   constructor
  */
-last_letter::last_letter(const char *home_str, const char *frame_str) :
-    Aircraft(home_str, frame_str),
+last_letter::last_letter(const char *home_str, const char *_frame_str) :
+    Aircraft(home_str, _frame_str),
     last_timestamp_us(0),
-    sock(true)
+    sock(true),
+    frame_str(_frame_str)
 {
     // try to bind to a specific port so that if we restart ArduPilot
     // last_letter keeps sending us packets. Not strictly necessary but
@@ -52,31 +53,39 @@ last_letter::last_letter(const char *home_str, const char *frame_str) :
 void last_letter::start_last_letter(void)
 {
     pid_t child_pid = fork();
-    if (child_pid == 0) {
-        close(0);
-        open("/dev/null", O_RDONLY);
-        // in child
-        for (uint8_t i=3; i<100; i++) {
-            close(i);
-        }
-
-        char argHome[50];
-        sprintf(argHome,"home:=[%f,%f,%f]",home.lat*1.0e-7,home.lng*1.0e-7,(double)home.alt*1.0e-2);
-
-        int ret = execlp("roslaunch",
-                         "roslaunch",
-                         "last_letter",
-                         "launcher.launch",
-                         "ArduPlane:=true",
-                         "simRate:=500",
-                         "deltaT:=0.002",
-                         argHome,
-                         NULL);
-        if (ret != 0) {
-            perror("roslaunch");
-        }
-        exit(1);
+    if (child_pid != 0) {
+        return;
     }
+
+    // in child
+    close(0);
+    open("/dev/null", O_RDONLY);
+    for (uint8_t i=3; i<100; i++) {
+        close(i);
+    }
+
+    char argHome[50];
+    sprintf(argHome,"home:=[%f,%f,%f]",home.lat*1.0e-7,home.lng*1.0e-7,(double)home.alt*1.0e-2);
+
+    const char *uav_name = strchr(frame_str, ':');
+    if (uav_name != NULL) {
+        uav_name++;
+    }
+
+    int ret = execlp("roslaunch",
+                     "roslaunch",
+                     "last_letter",
+                     "launcher.launch",
+                     "ArduPlane:=true",
+                     "simRate:=500",
+                     "deltaT:=0.002",
+                     argHome,
+                     uav_name,
+                     NULL);
+    if (ret != 0) {
+        perror("roslaunch");
+    }
+    exit(1);
 }
 
 /*

libraries/SITL/SIM_last_letter.h

@@ -70,6 +70,8 @@ private:
 
     uint64_t last_timestamp_us;
     SocketAPM sock;
+
+    const char *frame_str;
 };