Reland: Introduce sys_sigprocmask and sys_sigaction. (patchset #5 id:160001 of https://codereview.c…

sandbox/linux/services/credentials.cc

 // Copyright (c) 2013 The Chromium 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 "sandbox/linux/services/credentials.h"
 
 #include <errno.h>
 #include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/process/launch.h"
 #include "base/template_util.h"
 #include "base/third_party/valgrind/valgrind.h"
 #include "build/build_config.h"
 #include "sandbox/linux/services/namespace_utils.h"
 #include "sandbox/linux/services/proc_util.h"
 #include "sandbox/linux/services/syscall_wrappers.h"
 #include "sandbox/linux/services/thread_helpers.h"
 #include "sandbox/linux/system_headers/capability.h"
+#include "sandbox/linux/system_headers/linux_signal.h"
 
 namespace sandbox {
 
 namespace {
 
-// Signal ABI for some toolchain is incompatible with Linux's. In particular,
-// PNaCl toolchain defines SIGCHLD = 20. So, here, directly define Linux's
-// value.
-const int kLinuxSIGCHLD = 17;
-
 bool IsRunningOnValgrind() { return RUNNING_ON_VALGRIND; }
 
 // Checks that the set of RES-uids and the set of RES-gids have
 // one element each and return that element in |resuid| and |resgid|
 // respectively. It's ok to pass NULL as one or both of the ids.
 bool GetRESIds(uid_t* resuid, gid_t* resgid) {
   uid_t ruid, euid, suid;
   gid_t rgid, egid, sgid;
   PCHECK(sys_getresuid(&ruid, &euid, &suid) == 0);
   PCHECK(sys_getresgid(&rgid, &egid, &sgid) == 0);
@@ skipping 39 matching lines @@
   char stack_buf[PTHREAD_STACK_MIN];
 #if defined(ARCH_CPU_X86_FAMILY) || defined(ARCH_CPU_ARM_FAMILY) || \
     defined(ARCH_CPU_MIPS64_FAMILY) || defined(ARCH_CPU_MIPS_FAMILY)
   // The stack grows downward.
   void* stack = stack_buf + sizeof(stack_buf);
 #else
 #error "Unsupported architecture"
 #endif
 
   pid = clone(ChrootToSelfFdinfo, stack,
-              CLONE_VM | CLONE_VFORK | CLONE_FS | kLinuxSIGCHLD,
-              nullptr, nullptr, nullptr, nullptr);
+              CLONE_VM | CLONE_VFORK | CLONE_FS | LINUX_SIGCHLD, nullptr,
+              nullptr, nullptr, nullptr);
   PCHECK(pid != -1);
 
   int status = -1;
   PCHECK(HANDLE_EINTR(waitpid(pid, &status, 0)) == pid);
 
   return WIFEXITED(status) && WEXITSTATUS(status) == kExitSuccess;
 }
 
 // CHECK() that an attempt to move to a new user namespace raised an expected
 // errno.
@@ skipping 183 matching lines @@
   CHECK_LE(0, proc_fd);
 
   CHECK(ChrootToSafeEmptyDir());
   CHECK(!base::DirectoryExists(base::FilePath("/proc")));
   CHECK(!ProcUtil::HasOpenDirectory(proc_fd));
   // We never let this function fail.
   return true;
 }
 
 }  // namespace sandbox.