Linux sandbox: change API to start the sandbox

content/zygote/zygote_main_linux.cc

Index: content/zygote/zygote_main_linux.cc
diff --git a/content/zygote/zygote_main_linux.cc b/content/zygote/zygote_main_linux.cc
index 361511e37374cee7b9546059d05fb8f2405ad411..c5860e4052c9fff015fc8edac9f8013c711fcf4c 100644
--- a/content/zygote/zygote_main_linux.cc
+++ b/content/zygote/zygote_main_linux.cc
@@ -13,6 +13,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
@@ -101,6 +103,13 @@ void InstallSandboxCrashTestHandler() {
 
   PCHECK(0 == sigaction(SIGUSR2, &act, NULL));
 }
+
+void CloseFds(const std::vector<int>& fds) {
+  for (const auto& it : fds) {
+    PCHECK(0 == IGNORE_EINTR(close(it)));
+  }
+}
+
 }  // namespace
 
 // See http://code.google.com/p/chromium/wiki/LinuxZygote
@@ -494,13 +503,17 @@ static void CreateSanitizerCoverageSocketPair(int fds[2]) {
   PCHECK(0 == shutdown(fds[1], SHUT_RD));
 }
 
-static pid_t ForkSanitizerCoverageHelper(int child_fd, int parent_fd,
-                                        base::ScopedFD file_fd) {
+static pid_t ForkSanitizerCoverageHelper(
+    int child_fd,
+    int parent_fd,
+    base::ScopedFD file_fd,
+    const std::vector<int>& extra_fds_to_close) {
   pid_t pid = fork();
   PCHECK(pid >= 0);
   if (pid == 0) {
     // In the child.
     PCHECK(0 == IGNORE_EINTR(close(parent_fd)));
+    CloseFds(extra_fds_to_close);
     SanitizerCoverageHelper(child_fd, file_fd.get());
     _exit(0);
   } else {
@@ -510,10 +523,6 @@ static pid_t ForkSanitizerCoverageHelper(int child_fd, int parent_fd,
   }
 }
 
-void CloseFdPair(const int fds[2]) {
-  PCHECK(0 == IGNORE_EINTR(close(fds[0])));
-  PCHECK(0 == IGNORE_EINTR(close(fds[1])));
-}
 #endif  // defined(ADDRESS_SANITIZER)
 
 // If |is_suid_sandbox_child|, then make sure that the setuid sandbox is
@@ -544,7 +553,7 @@ bool ZygoteMain(const MainFunctionParams& params,
   g_am_zygote_or_renderer = true;
   sandbox::InitLibcUrandomOverrides();
 
-  base::Closure *post_fork_parent_callback = NULL;
+  std::vector<int> fds_to_close_post_fork;
 
   LinuxSandbox* linux_sandbox = LinuxSandbox::GetInstance();
 
@@ -562,9 +571,8 @@ bool ZygoteMain(const MainFunctionParams& params,
   // Zygote termination will block until the helper process exits, which will
   // not happen until the write end of the socket is closed everywhere. Make
   // sure the init process does not hold on to it.
-  base::Closure close_sancov_socket_fds =
-      base::Bind(&CloseFdPair, sancov_socket_fds);
-  post_fork_parent_callback = &close_sancov_socket_fds;
+  fds_to_close_post_fork.push_back(sancov_socket_fds[0]);
+  fds_to_close_post_fork.push_back(sancov_socket_fds[1]);
 #endif
 
   // This will pre-initialize the various sandboxes that need it.
@@ -590,16 +598,28 @@ bool ZygoteMain(const MainFunctionParams& params,
     (*i)->Init(GetSandboxFD(), must_enable_setuid_sandbox);
   }
 
+  const std::vector<int> sandbox_fds_to_close_post_fork =
+      linux_sandbox->GetFileDescriptorsToClose();
+
+  fds_to_close_post_fork.insert(fds_to_close_post_fork.end(),
+                                sandbox_fds_to_close_post_fork.begin(),
+                                sandbox_fds_to_close_post_fork.end());
+  base::Closure post_fork_parent_callback =
+      base::Bind(&CloseFds, fds_to_close_post_fork);
+
   // Turn on the first layer of the sandbox if the configuration warrants it.
   EnterLayerOneSandbox(linux_sandbox, must_enable_setuid_sandbox,
-                       post_fork_parent_callback);
+                       &post_fork_parent_callback);
 
+  // Extra children and file descriptors created that the Zygote must have
+  // knowledge of.
   std::vector<pid_t> extra_children;
   std::vector<int> extra_fds;
 
 #if defined(ADDRESS_SANITIZER)
   pid_t sancov_helper_pid = ForkSanitizerCoverageHelper(
-      sancov_socket_fds[0], sancov_socket_fds[1], sancov_file_fd.Pass());
+      sancov_socket_fds[0], sancov_socket_fds[1], sancov_file_fd.Pass(),
+      sandbox_fds_to_close_post_fork);
   // It's important that the zygote reaps the helper before dying. Otherwise,
   // the destruction of the PID namespace could kill the helper before it
   // completes its I/O tasks. |sancov_helper_pid| will exit once the last