Allow sel_ldr to continue without the IRT, when nexe doesn't have segment gap

src/trusted/service_runtime/sel_main.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*
  * NaCl Simple/secure ELF loader (NaCl SEL).
  */
 #include "native_client/src/include/portability.h"
@@ skipping 660 matching lines @@
         fprintf(stderr, "NaClAppPrepareToLaunch returned %d", errcode);
       }
       NaClPerfCounterMark(&time_all_main, "AppPrepLaunch");
       NaClPerfCounterIntervalLast(&time_all_main);
     }
 
     /* Give debuggers a well known point at which xlate_base is known.  */
     NaClGdbHook(&state);
   }
 
-
   if (NULL != blob_library_file) {
     if (LOAD_OK == errcode) {
-      NaClLog(2, "Loading blob file %s\n", blob_library_file);
-      errcode = NaClAppLoadFileDynamically(nap, (struct Gio *) &blob_file);
-      if (LOAD_OK != errcode) {
-        fprintf(stderr, "Error while loading \"%s\": %s\n",
-                blob_library_file,
-                NaClErrorString(errcode));
+      if (NULL != nap->text_shm) {
+        NaClLog(2, "Loading blob file %s\n", blob_library_file);
+        errcode = NaClAppLoadFileDynamically(nap, (struct Gio *) &blob_file);
+        if (LOAD_OK != errcode) {
+          fprintf(stderr, "Error while loading \"%s\": %s\n",
+                  blob_library_file,
+                  NaClErrorString(errcode));
+        }
+        NaClPerfCounterMark(&time_all_main, "BlobLoaded");
+        NaClPerfCounterIntervalLast(&time_all_main);
+      } else {
+        /*
+         * TODO(mseaborn): Omit -B when the IRT is not wanted (e.g., from
+         * sel_ldr_launcher_standalone), instead of looking for the absence
+         * of a segment gap, when the nexe does not follow NaCl's stable ABI.
+         */
+        NaClLog(LOG_WARNING,
+                "Main executable has no segment gap; not loading IRT library. "
+                "This is expected for PNaCl's translator nexes.\n");
       }
-      NaClPerfCounterMark(&time_all_main, "BlobLoaded");
-      NaClPerfCounterIntervalLast(&time_all_main);
     }
 
     if (-1 == (*((struct Gio *) &blob_file)->vtbl->Close)((struct Gio *)
                                                           &blob_file)) {
       fprintf(stderr, "Error while closing \"%s\".\n", blob_library_file);
     }
     (*((struct Gio *) &blob_file)->vtbl->Dtor)((struct Gio *) &blob_file);
     if (verbosity) {
       gprintf((struct Gio *) &gout, "printing post-IRT NaClApp details\n");
       NaClAppPrintDetails(nap, (struct Gio *) &gout);
@@ skipping 170 matching lines @@
   fflush(stdout);
 
   if (handle_signals) NaClSignalHandlerFini();
   NaClAllModulesFini();
 
   NaClExit(ret_code);
 
   /* Unreachable, but having the return prevents a compiler error. */
   return ret_code;
 }