add option --T_dont_fork to tracee (lte-softmodem, oaisim)

The T has 2 processes: the tracee and the local tracer
if the tracee dies (segfault or whatever) the tracee
may still be running.

So there is a third process that monitors those two others
and kill everything when one dies.

The problem is that this third process has to be the parent
of the two others. That makes debugging the tracee with gdb
impossible. This new option disables the third monitor process.

common/utils/T/T.c

@@ -107,7 +107,7 @@ static void monitor_and_kill(int child1, int child2)
   exit(0);
 }
 
-void T_init(int remote_port, int wait_for_tracer)
+void T_init(int remote_port, int wait_for_tracer, int dont_fork)
 {
   int socket_pair[2];
   int s;
@@ -117,7 +117,7 @@ void T_init(int remote_port, int wait_for_tracer)
   if (socketpair(AF_UNIX, SOCK_STREAM, 0, socket_pair))
     { perror("socketpair"); abort(); }
 
-  /* child1 runs the local tracer and child2 runs the tracee */
+  /* child1 runs the local tracer and child2 (or main) runs the tracee */
 
   child1 = fork(); if (child1 == -1) abort();
   if (child1 == 0) {
@@ -127,10 +127,12 @@ void T_init(int remote_port, int wait_for_tracer)
   }
   close(socket_pair[0]);
 
-  child2 = fork(); if (child2 == -1) abort();
-  if (child2 != 0) {
-    close(socket_pair[1]);
-    monitor_and_kill(child1, child2);
+  if (dont_fork == 0) {
+    child2 = fork(); if (child2 == -1) abort();
+    if (child2 != 0) {
+      close(socket_pair[1]);
+      monitor_and_kill(child1, child2);
+    }
   }
 
   s = socket_pair[1];

common/utils/T/T.h

@@ -562,7 +562,7 @@ extern T_cache_t *T_cache;
 
 extern int *T_active;
 
-void T_init(int remote_port, int wait_for_tracer);
+void T_init(int remote_port, int wait_for_tracer, int dont_fork);
 
 #else /* T_TRACER */
 

targets/RT/USER/lte-softmodem.c

@@ -490,6 +490,7 @@ void help (void) {
 #if T_TRACER
   printf("  --T_port [port]    use given port\n");
   printf("  --T_nowait         don't wait for tracer, start immediately\n");
+  printf("  --T_dont_fork      to ease debugging with gdb\n");
 #endif
   printf(RESET);
   fflush(stdout);
@@ -2332,6 +2333,7 @@ static void get_options (int argc, char **argv)
 #if T_TRACER
     LONG_OPTION_T_PORT,
     LONG_OPTION_T_NOWAIT,
+    LONG_OPTION_T_DONT_FORK,
 #endif
   };
 
@@ -2355,6 +2357,7 @@ static void get_options (int argc, char **argv)
 #if T_TRACER
     {"T_port",                 required_argument, 0, LONG_OPTION_T_PORT},
     {"T_nowait",               no_argument,       0, LONG_OPTION_T_NOWAIT},
+    {"T_dont_fork",            no_argument,       0, LONG_OPTION_T_DONT_FORK},
 #endif
 
     {NULL, 0, NULL, 0}
@@ -2457,6 +2460,12 @@ static void get_options (int argc, char **argv)
       T_wait = 0;
       break;
     }
+
+    case LONG_OPTION_T_DONT_FORK: {
+      extern int T_dont_fork;
+      T_dont_fork = 1;
+      break;
+    }
 #endif
 
     case 'A':
@@ -2822,6 +2831,7 @@ static void get_options (int argc, char **argv)
 #if T_TRACER
 int T_wait = 1;       /* by default we wait for the tracer */
 int T_port = 2021;    /* default port to listen to to wait for the tracer */
+int T_dont_fork = 0;  /* default is to fork, see 'T_init' to understand */
 #endif
 
 int main( int argc, char **argv )
@@ -2894,7 +2904,7 @@ int main( int argc, char **argv )
     openair0_cfg[0].configFilename = rf_config_file;
   
 #if T_TRACER
-  T_init(T_port, T_wait);
+  T_init(T_port, T_wait, T_dont_fork);
 #endif
 
   // initialize the log (see log.h for details)

targets/SIMU/USER/oaisim.c

@@ -250,6 +250,7 @@ help (void)
 #if T_TRACER
   printf ("--T_port [port]    use given port\n");
   printf ("--T_nowait         don't wait for tracer, start immediately\n");
+  printf ("--T_dont_fork      to ease debugging with gdb\n");
 #endif
 }
 
@@ -1258,6 +1259,7 @@ l2l1_task (void *args_p)
 #if T_TRACER
 int T_wait = 1;       /* by default we wait for the tracer */
 int T_port = 2021;    /* default port to listen to to wait for the tracer */
+int T_dont_fork = 0;  /* default is to fork, see 'T_init' to understand */
 #endif
 
 /*------------------------------------------------------------------------------*/
@@ -1294,7 +1296,7 @@ main (int argc, char **argv)
   get_simulation_options (argc, argv); //Command-line options
 
 #if T_TRACER
-  T_init(T_port, T_wait);
+  T_init(T_port, T_wait, T_dont_fork);
 #endif
 
   // Initialize VCD LOG module

targets/SIMU/USER/oaisim_functions.c

@@ -216,6 +216,7 @@ void get_simulation_options(int argc, char *argv[])
 #if T_TRACER
     LONG_OPTION_T_PORT,
     LONG_OPTION_T_NOWAIT,
+    LONG_OPTION_T_DONT_FORK,
 #endif
   };
 
@@ -254,6 +255,7 @@ void get_simulation_options(int argc, char *argv[])
 #if T_TRACER
     {"T_port",                 required_argument, 0, LONG_OPTION_T_PORT},
     {"T_nowait",               no_argument,       0, LONG_OPTION_T_NOWAIT},
+    {"T_dont_fork",            no_argument,       0, LONG_OPTION_T_DONT_FORK},
 #endif
 
     {NULL, 0, NULL, 0}
@@ -436,6 +438,12 @@ void get_simulation_options(int argc, char *argv[])
       T_wait = 0;
       break;
     }
+
+    case LONG_OPTION_T_DONT_FORK: {
+      extern int T_dont_fork;
+      T_dont_fork = 1;
+      break;
+    }
 #endif
 
     case 'a':