IRT: Replace __attribute__((constructor)) with explicit call in _start()

src/untrusted/irt/irt_entry.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 <assert.h>
 #include <unistd.h>
 
 #include "native_client/src/include/elf32.h"
 #include "native_client/src/include/elf_auxv.h"
+#include "native_client/src/shared/platform/nacl_log.h"
+#include "native_client/src/shared/srpc/nacl_srpc.h"
 #include "native_client/src/untrusted/irt/irt_interfaces.h"
 #include "native_client/src/untrusted/nacl/nacl_irt.h"
 #include "native_client/src/untrusted/nacl/nacl_startup.h"
 #include "native_client/src/untrusted/nacl/tls.h"
 
 void __libc_init_array(void);
 
 /*
+ * This is declared as weak because plugin_main_nacl.cc on the
+ * Chromium side has a copy of IrtInit().
+ * TODO(mseaborn): Remove IrtInit() from there and use this copy.
+ */
+__attribute__((weak))
+int IrtInit(void) {
+  static int initialized = 0;
+  if (initialized) {
+    return 0;
+  }
+  if (!NaClSrpcModuleInit()) {
+    return 1;
+  }
+  NaClLogModuleInit();  /* Enable NaClLog'ing used by CHECK(). */
+  initialized = 1;
+  return 0;
+}
+
+/*
  * This is the true entry point for untrusted code.
  * See nacl_startup.h for the layout at the argument pointer.
  */
 void _start(uint32_t *info) {
   void (*fini)(void) = nacl_startup_fini(info);
   char **envp = nacl_startup_envp(info);
   Elf32_auxv_t *auxv = nacl_startup_auxv(info);
 
   environ = envp;
 
   /*
    * We are the true entry point, never called by a dynamic linker.
    * So the finalizer function pointer is always NULL.
    * We don't bother registering anything with atexit anyway,
    * since we do not expect our own exit function ever to be called.
    * Any cleanup we might need done must happen in nacl_irt_exit (irt_basic.c).
    */
   assert(fini == NULL);
 
   __pthread_initialize();
 
   __libc_init_array();
 
+  if (IrtInit()) {
+    static const char fatal_msg[] = "IrtInit() failed\n";
+    write(2, fatal_msg, sizeof(fatal_msg) - 1);
+    _exit(-1);
+  }
+
   Elf32_auxv_t *entry = NULL;
   for (Elf32_auxv_t *av = auxv; av->a_type != AT_NULL; ++av) {
     if (av->a_type == AT_ENTRY) {
       entry = av;
       break;
     }
   }
   if (entry == NULL) {
     static const char fatal_msg[] =
         "irt_entry: No AT_ENTRY item found in auxv.  "
@@ skipping 20 matching lines @@
    */
   _exit(0);
 }
 
 /*
  * This is never actually called, but there is an artificial undefined
  * reference to it.
  */
 int main(void) {
 }