Set up NaClChromeMainArgs number_of_cores member so apps can size threadpools

appropriately

The outer sandbox on Linux and OSX was preventing
sysconf(_SC_NPROCESSORS_ONLN) from succeeding, so that NaCl applications that
need the number of processors/cores to, e.g., figure out the appropriate size
for threadpools were getting a bogus value (-1 when using newlib and 1 when
using glibc).

This is a reland of r195198 (https://chromiumcodereview.appspot.com/14238013)
which was reverted because of a test failure on an XP bot.  Having built (on
Win7) and moved the filesystem to an XP laptop to verify that no test failure
occurs, and bradn having helped to verify on a bot (VM configured similarly to
chrome's build waterfall bots), we suspect that the original test failure was
a bot issue (test timed out!).

TEST= browser_tests --gtest_filter=*ysconf*
BUG= 176522

Review URL: https://chromiumcodereview.appspot.com/16047003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@204389 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 38 insertions, 4 deletions

diff --git a/chrome/nacl/nacl_helper_linux.cc b/chrome/nacl/nacl_helper_linux.cc
index f8f32c4..5c56285 100644
--- a/chrome/nacl/nacl_helper_linux.cc
+++ b/chrome/nacl/nacl_helper_linux.cc
@@ -40,7 +40,8 @@ namespace {
 //   if (!child) {
 // Note: this code doesn't attempt to support the SECCOMP sandbox.
 void BecomeNaClLoader(const std::vector<int>& child_fds,
-                      size_t prereserved_sandbox_size) {
+                      size_t prereserved_sandbox_size,
+                      int number_of_cores) {
   VLOG(1) << "NaCl loader: setting up IPC descriptor";
   // don't need zygote FD any more
   if (HANDLE_EINTR(close(kNaClZygoteDescriptor)) != 0)
@@ -51,6 +52,7 @@ void BecomeNaClLoader(const std::vector<int>& child_fds,
   base::MessageLoopForIO main_message_loop;
   NaClListener listener;
   listener.set_prereserved_sandbox_size(prereserved_sandbox_size);
+  listener.set_number_of_cores(number_of_cores);
   listener.Listen();
   _exit(0);
 }
@@ -58,7 +60,8 @@ void BecomeNaClLoader(const std::vector<int>& child_fds,
 // Some of this code was lifted from
 // content/browser/zygote_main_linux.cc:ForkWithRealPid()
 void HandleForkRequest(const std::vector<int>& child_fds,
-                       size_t prereserved_sandbox_size) {
+                       size_t prereserved_sandbox_size,
+                       int number_of_cores) {
   VLOG(1) << "nacl_helper: forking";
   pid_t childpid = fork();
   if (childpid < 0) {
@@ -96,7 +99,7 @@ void HandleForkRequest(const std::vector<int>& child_fds,
     if (HANDLE_EINTR(close(child_fds[kNaClParentFDIndex])) != 0)
       LOG(ERROR) << "close(child_fds[kNaClParentFDIndex]) failed";
     if (validack) {
-      BecomeNaClLoader(child_fds, prereserved_sandbox_size);
+      BecomeNaClLoader(child_fds, prereserved_sandbox_size, number_of_cores);
     } else {
       LOG(ERROR) << "Failed to synch with zygote";
     }
@@ -234,6 +237,7 @@ int main(int argc, char* argv[]) {
 #endif
   std::vector<int> empty; // for SendMsg() calls
   size_t prereserved_sandbox_size = CheckReservedAtZero();
+  int number_of_cores = sysconf(_SC_NPROCESSORS_ONLN);
 
   CheckRDebug(argv[0]);
 
@@ -270,7 +274,7 @@ int main(int argc, char* argv[]) {
     } else if (msglen == sizeof(kNaClForkRequest) - 1 &&
                memcmp(buf, kNaClForkRequest, msglen) == 0) {
       if (kNaClParentFDIndex + 1 == fds.size()) {
-        HandleForkRequest(fds, prereserved_sandbox_size);
+        HandleForkRequest(fds, prereserved_sandbox_size, number_of_cores);
         continue;  // fork succeeded. Note: child does not return
       } else {
         LOG(ERROR) << "nacl_helper: unexpected number of fds, got "
diff --git a/chrome/nacl/nacl_listener.cc b/chrome/nacl/nacl_listener.cc
index e771496..ac03a31 100644
--- a/chrome/nacl/nacl_listener.cc
+++ b/chrome/nacl/nacl_listener.cc
@@ -7,6 +7,10 @@
 #include <errno.h>
 #include <stdlib.h>
 
+#if defined(OS_POSIX)
+#include <unistd.h>
+#endif
+
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ -174,6 +178,9 @@ NaClListener::NaClListener() : shutdown_event_(true, false),
 #if defined(OS_LINUX)
                                prereserved_sandbox_size_(0),
 #endif
+#if defined(OS_POSIX)
+                               number_of_cores_(-1),  // unknown/error
+#endif
                                main_loop_(NULL) {
   io_thread_.StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
@@ -260,6 +267,7 @@ void NaClListener::OnStart(const nacl::NaClStartParams& params) {
     LOG(ERROR) << "Failed to dup() the urandom FD";
     return;
   }
+  args->number_of_cores = number_of_cores_;
   args->create_memory_object_func = CreateMemoryObject;
 # if defined(OS_MACOSX)
   CHECK(handles.size() >= 1);
diff --git a/chrome/nacl/nacl_listener.h b/chrome/nacl/nacl_listener.h
index 2936eee..a6cec25 100644
--- a/chrome/nacl/nacl_listener.h
+++ b/chrome/nacl/nacl_listener.h
@@ -34,6 +34,11 @@ class NaClListener : public IPC::Listener {
     prereserved_sandbox_size_ = prereserved_sandbox_size;
   }
 #endif
+#if defined(OS_POSIX)
+  void set_number_of_cores(int number_of_cores) {
+    number_of_cores_ = number_of_cores;
+  }
+#endif
 
  private:
   void OnStart(const nacl::NaClStartParams& params);
@@ -51,6 +56,14 @@ class NaClListener : public IPC::Listener {
 #if defined(OS_LINUX)
   size_t prereserved_sandbox_size_;
 #endif
+#if defined(OS_POSIX)
+  // The outer sandbox on Linux and OSX prevents
+  // sysconf(_SC_NPROCESSORS) from working; in Windows, there are no
+  // problems with invoking GetSystemInfo.  Therefore, only in
+  // OS_POSIX do we need to supply the number of cores into the
+  // NaClChromeMainArgs object.
+  int number_of_cores_;
+#endif
 
   // Used to identify what thread we're on.
   base::MessageLoop* main_loop_;
diff --git a/chrome/nacl/nacl_main.cc b/chrome/nacl/nacl_main.cc
index fa4835e..112a9c4 100644
--- a/chrome/nacl/nacl_main.cc
+++ b/chrome/nacl/nacl_main.cc
@@ -33,6 +33,12 @@ int NaClMain(const content::MainFunctionParams& parameters) {
   bool no_sandbox = parsed_command_line.HasSwitch(switches::kNoSandbox);
   platform.InitSandboxTests(no_sandbox);
 
+#if defined(OS_POSIX)
+  // The number of cores must be obtained before the invocation of
+  // platform.EnableSandbox(), so cannot simply be inlined below.
+  int number_of_cores = sysconf(_SC_NPROCESSORS_ONLN);
+#endif
+
   if (!no_sandbox) {
     platform.EnableSandbox();
   }
@@ -40,6 +46,9 @@ int NaClMain(const content::MainFunctionParams& parameters) {
 
   if (sandbox_test_result) {
     NaClListener listener;
+#if defined(OS_POSIX)
+    listener.set_number_of_cores(number_of_cores);
+#endif
     listener.Listen();
   } else {
     // This indirectly prevents the test-harness-success-cookie from being set,