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

src/trusted/service_runtime/sel_main_chrome.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.
  */
 
 #include "native_client/src/trusted/service_runtime/sel_main_chrome.h"
 
 #include "native_client/src/include/portability.h"
 #include "native_client/src/include/portability_io.h"
@@ skipping 12 matching lines @@
 #include "native_client/src/trusted/desc/nacl_desc_io.h"
 #include "native_client/src/trusted/fault_injection/fault_injection.h"
 #include "native_client/src/trusted/gio/gio_nacl_desc.h"
 #include "native_client/src/trusted/service_runtime/include/sys/fcntl.h"
 #include "native_client/src/trusted/service_runtime/nacl_globals.h"
 #include "native_client/src/trusted/service_runtime/env_cleanser.h"
 #include "native_client/src/trusted/service_runtime/nacl_app.h"
 #include "native_client/src/trusted/service_runtime/nacl_all_modules.h"
 #include "native_client/src/trusted/service_runtime/nacl_debug_init.h"
 #include "native_client/src/trusted/service_runtime/nacl_signal.h"
+#include "native_client/src/trusted/service_runtime/nacl_text.h"
 #include "native_client/src/trusted/service_runtime/osx/mach_exception_handler.h"
 #include "native_client/src/trusted/service_runtime/sel_addrspace.h"
 #include "native_client/src/trusted/service_runtime/sel_ldr.h"
 #include "native_client/src/trusted/service_runtime/sel_qualify.h"
 #include "native_client/src/trusted/service_runtime/win/exception_patch/ntdll_patch.h"
 
 struct NaClChromeMainArgs *NaClChromeMainArgsCreate(void) {
   struct NaClChromeMainArgs *args = malloc(sizeof(*args));
   if (args == NULL)
     return NULL;
@@ skipping 231 matching lines @@
   }
 
   /*
    * error reporting done; can quit now if there was an error earlier.
    */
   if (LOAD_OK != errcode) {
     goto done;
   }
 
   /* Load the integrated runtime (IRT) library. */
-  NaClLoadIrt(nap, args->irt_fd);
+  /* We check if there is a segment gap before trying to load the IRT.  This

[Mark Seaborn, 2012/06/28 22:05:11]

The comment style is
/*
 * blah
 * blah
 */

Can you combine this with the comment on the previous line?

[jvoung (off chromium), 2012/06/28 22:41:56]

Done.

+   * is to support IRT-less / segment-gap-free PNaCl translator nexes.
+   * We should plumb through a flag from Chrome in such cases, instead of

[Mark Seaborn, 2012/06/28 22:05:11]

Can you make this: "TODO(mseaborn): Plumb through a flag from Chromium for such
cases..." as a reminder to me.

[jvoung (off chromium), 2012/06/28 22:41:56]

Done.

+   * looking for the absence of a segment gap, to provide better diagnostics
+   * when the linker did not create a segment gap!
+   */
+  if (NaClHasSegmentGapForDyncode(nap)) {
+    NaClLoadIrt(nap, args->irt_fd);
+  } else {
+    NaClLog(LOG_WARNING,
+            "NaCl app doesn't have a segment gap, not loading IRT.\n"

[Mark Seaborn, 2012/06/28 22:05:11]

'executable' rather than 'app'?  "Main executable has no segment gap; skipping
loading IRT library..."

[jvoung (off chromium), 2012/06/28 22:41:56]

Done.

+            "This is expected for PNaCl's translator nexes.\n");
+  }
 
   NaClEnvCleanserCtor(&env_cleanser, 1);
   if (!NaClEnvCleanserInit(&env_cleanser, envp, NULL)) {
     NaClLog(LOG_FATAL, "Failed to initialise env cleanser\n");
   }
 
   if (!NaClAppLaunchServiceThreads(nap)) {
     fprintf(stderr, "Launch service threads failed\n");
     goto done;
   }
@@ skipping 37 matching lines @@
   if (LOAD_OK != errcode) {
     NaClBlockIfCommandChannelExists(nap);
   }
 
  done_ctor:
 
   NaClAllModulesFini();
 
   NaClExit(ret_code);
 }