Implement <spawn.h>.

As described here:

  http://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_spawn.html

And here:

  http://man7.org/linux/man-pages/man3/posix_spawn.3.html

Bug: N/A (but mentioned in my inbox since 2013)
Test: ran tests
Change-Id: I0b27b2919b660779e3bd8a25fb429527c16dc621
diff --git a/tests/Android.bp b/tests/Android.bp
index fb8b886..7094d77 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -105,6 +105,7 @@
         "semaphore_test.cpp",
         "setjmp_test.cpp",
         "signal_test.cpp",
+        "spawn_test.cpp",
         "stack_protector_test.cpp",
         "stack_protector_test_helper.cpp",
         "stack_unwinding_test.cpp",
diff --git a/tests/spawn_test.cpp b/tests/spawn_test.cpp
new file mode 100644
index 0000000..6a3920e
--- /dev/null
+++ b/tests/spawn_test.cpp
@@ -0,0 +1,388 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <spawn.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <gtest/gtest.h>
+
+#include "utils.h"
+
+#include <android-base/file.h>
+#include <android-base/strings.h>
+
+// Old versions of glibc didn't have POSIX_SPAWN_SETSID.
+#if __GLIBC__
+# if !defined(POSIX_SPAWN_SETSID)
+#  define POSIX_SPAWN_SETSID 0
+# endif
+#endif
+
+TEST(spawn, posix_spawnattr_init_posix_spawnattr_destroy) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setflags_EINVAL) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+  ASSERT_EQ(EINVAL, posix_spawnattr_setflags(&sa, ~0));
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setflags_posix_spawnattr_getflags) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, POSIX_SPAWN_RESETIDS));
+  short flags;
+  ASSERT_EQ(0, posix_spawnattr_getflags(&sa, &flags));
+  ASSERT_EQ(POSIX_SPAWN_RESETIDS, flags);
+
+  constexpr short all_flags = POSIX_SPAWN_RESETIDS | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_SETSIGDEF |
+                              POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSCHEDPARAM |
+                              POSIX_SPAWN_SETSCHEDULER | POSIX_SPAWN_USEVFORK | POSIX_SPAWN_SETSID;
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, all_flags));
+  ASSERT_EQ(0, posix_spawnattr_getflags(&sa, &flags));
+  ASSERT_EQ(all_flags, flags);
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setpgroup_posix_spawnattr_getpgroup) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  ASSERT_EQ(0, posix_spawnattr_setpgroup(&sa, 123));
+  pid_t g;
+  ASSERT_EQ(0, posix_spawnattr_getpgroup(&sa, &g));
+  ASSERT_EQ(123, g);
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setsigmask_posix_spawnattr_getsigmask) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  sigset_t sigs;
+  ASSERT_EQ(0, posix_spawnattr_getsigmask(&sa, &sigs));
+  ASSERT_FALSE(sigismember(&sigs, SIGALRM));
+
+  sigset_t just_SIGALRM;
+  sigemptyset(&just_SIGALRM);
+  sigaddset(&just_SIGALRM, SIGALRM);
+  ASSERT_EQ(0, posix_spawnattr_setsigmask(&sa, &just_SIGALRM));
+
+  ASSERT_EQ(0, posix_spawnattr_getsigmask(&sa, &sigs));
+  ASSERT_TRUE(sigismember(&sigs, SIGALRM));
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setsigdefault_posix_spawnattr_getsigdefault) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  sigset_t sigs;
+  ASSERT_EQ(0, posix_spawnattr_getsigdefault(&sa, &sigs));
+  ASSERT_FALSE(sigismember(&sigs, SIGALRM));
+
+  sigset_t just_SIGALRM;
+  sigemptyset(&just_SIGALRM);
+  sigaddset(&just_SIGALRM, SIGALRM);
+  ASSERT_EQ(0, posix_spawnattr_setsigdefault(&sa, &just_SIGALRM));
+
+  ASSERT_EQ(0, posix_spawnattr_getsigdefault(&sa, &sigs));
+  ASSERT_TRUE(sigismember(&sigs, SIGALRM));
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setsschedparam_posix_spawnattr_getsschedparam) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  sched_param sp;
+  ASSERT_EQ(0, posix_spawnattr_getschedparam(&sa, &sp));
+  ASSERT_EQ(0, sp.sched_priority);
+
+  sched_param sp123 = { .sched_priority = 123 };
+  ASSERT_EQ(0, posix_spawnattr_setschedparam(&sa, &sp123));
+
+  ASSERT_EQ(0, posix_spawnattr_getschedparam(&sa, &sp));
+  ASSERT_EQ(123, sp.sched_priority);
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawnattr_setschedpolicy_posix_spawnattr_getschedpolicy) {
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  int p;
+  ASSERT_EQ(0, posix_spawnattr_getschedpolicy(&sa, &p));
+  ASSERT_EQ(0, p);
+
+  ASSERT_EQ(0, posix_spawnattr_setschedpolicy(&sa, SCHED_FIFO));
+
+  ASSERT_EQ(0, posix_spawnattr_getschedpolicy(&sa, &p));
+  ASSERT_EQ(SCHED_FIFO, p);
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawn) {
+  ExecTestHelper eth;
+  eth.SetArgs({BIN_DIR "true", nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawn(&pid, eth.GetArg0(), nullptr, nullptr, eth.GetArgs(), nullptr));
+  AssertChildExited(pid, 0);
+}
+
+TEST(spawn, posix_spawn_not_found) {
+  ExecTestHelper eth;
+  eth.SetArgs({"true", nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawn(&pid, eth.GetArg0(), nullptr, nullptr, eth.GetArgs(), nullptr));
+  AssertChildExited(pid, 127);
+}
+
+TEST(spawn, posix_spawnp) {
+  ExecTestHelper eth;
+  eth.SetArgs({"true", nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawnp(&pid, eth.GetArg0(), nullptr, nullptr, eth.GetArgs(), nullptr));
+  AssertChildExited(pid, 0);
+}
+
+TEST(spawn, posix_spawnp_not_found) {
+  ExecTestHelper eth;
+  eth.SetArgs({"does-not-exist", nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawnp(&pid, eth.GetArg0(), nullptr, nullptr, eth.GetArgs(), nullptr));
+  AssertChildExited(pid, 127);
+}
+
+TEST(spawn, posix_spawn_environment) {
+  ExecTestHelper eth;
+  eth.SetArgs({"sh", "-c", "exit $posix_spawn_environment_test", nullptr});
+  eth.SetEnv({"posix_spawn_environment_test=66", nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawnp(&pid, eth.GetArg0(), nullptr, nullptr, eth.GetArgs(), eth.GetEnv()));
+  AssertChildExited(pid, 66);
+}
+
+TEST(spawn, posix_spawn_file_actions) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  posix_spawn_file_actions_t fa;
+  ASSERT_EQ(0, posix_spawn_file_actions_init(&fa));
+
+  ASSERT_EQ(0, posix_spawn_file_actions_addclose(&fa, fds[0]));
+  ASSERT_EQ(0, posix_spawn_file_actions_adddup2(&fa, fds[1], 1));
+  ASSERT_EQ(0, posix_spawn_file_actions_addclose(&fa, fds[1]));
+  // Check that close(2) failures are ignored by closing the same fd again.
+  ASSERT_EQ(0, posix_spawn_file_actions_addclose(&fa, fds[1]));
+  ASSERT_EQ(0, posix_spawn_file_actions_addopen(&fa, 56, "/proc/version", O_RDONLY, 0));
+
+  ExecTestHelper eth;
+  eth.SetArgs({"ls", "-l", "/proc/self/fd", nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawnp(&pid, eth.GetArg0(), &fa, nullptr, eth.GetArgs(), eth.GetEnv()));
+  ASSERT_EQ(0, posix_spawn_file_actions_destroy(&fa));
+
+  ASSERT_EQ(0, close(fds[1]));
+  std::string content;
+  ASSERT_TRUE(android::base::ReadFdToString(fds[0], &content));
+  ASSERT_EQ(0, close(fds[0]));
+
+  AssertChildExited(pid, 0);
+
+  // We'll know the dup2 worked if we see any ls(1) output in our pipe.
+  // The open we can check manually...
+  bool open_to_fd_56_worked = false;
+  for (const auto& line : android::base::Split(content, "\n")) {
+    if (line.find(" 56 -> /proc/version") != std::string::npos) open_to_fd_56_worked = true;
+  }
+  ASSERT_TRUE(open_to_fd_56_worked);
+}
+
+static void CatFileToString(posix_spawnattr_t* sa, const char* path, std::string* content) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  posix_spawn_file_actions_t fa;
+  ASSERT_EQ(0, posix_spawn_file_actions_init(&fa));
+  ASSERT_EQ(0, posix_spawn_file_actions_addclose(&fa, fds[0]));
+  ASSERT_EQ(0, posix_spawn_file_actions_adddup2(&fa, fds[1], 1));
+  ASSERT_EQ(0, posix_spawn_file_actions_addclose(&fa, fds[1]));
+
+  ExecTestHelper eth;
+  eth.SetArgs({"cat", path, nullptr});
+  pid_t pid;
+  ASSERT_EQ(0, posix_spawnp(&pid, eth.GetArg0(), &fa, sa, eth.GetArgs(), nullptr));
+  ASSERT_EQ(0, posix_spawn_file_actions_destroy(&fa));
+
+  ASSERT_EQ(0, close(fds[1]));
+  ASSERT_TRUE(android::base::ReadFdToString(fds[0], content));
+  ASSERT_EQ(0, close(fds[0]));
+  AssertChildExited(pid, 0);
+}
+
+struct ProcStat {
+  pid_t pid;
+  pid_t ppid;
+  pid_t pgrp;
+  pid_t sid;
+};
+
+static void GetChildStat(posix_spawnattr_t* sa, ProcStat* ps) {
+  std::string content;
+  CatFileToString(sa, "/proc/self/stat", &content);
+
+  ASSERT_EQ(4, sscanf(content.c_str(), "%d (cat) %*c %d %d %d", &ps->pid, &ps->ppid, &ps->pgrp,
+                      &ps->sid));
+
+  ASSERT_EQ(getpid(), ps->ppid);
+}
+
+struct ProcStatus {
+  uint64_t sigblk;
+  uint64_t sigign;
+};
+
+static void GetChildStatus(posix_spawnattr_t* sa, ProcStatus* ps) {
+  std::string content;
+  CatFileToString(sa, "/proc/self/status", &content);
+
+  bool saw_blk = false;
+  bool saw_ign = false;
+  for (const auto& line : android::base::Split(content, "\n")) {
+    if (sscanf(line.c_str(), "SigBlk: %" SCNx64, &ps->sigblk) == 1) saw_blk = true;
+    if (sscanf(line.c_str(), "SigIgn: %" SCNx64, &ps->sigign) == 1) saw_ign = true;
+  }
+  ASSERT_TRUE(saw_blk);
+  ASSERT_TRUE(saw_ign);
+}
+
+TEST(spawn, posix_spawn_POSIX_SPAWN_SETSID_clear) {
+  pid_t parent_sid = getsid(0);
+
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, 0));
+
+  ProcStat ps = {};
+  GetChildStat(&sa, &ps);
+  ASSERT_EQ(parent_sid, ps.sid);
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawn_POSIX_SPAWN_SETSID_set) {
+  pid_t parent_sid = getsid(0);
+
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, POSIX_SPAWN_SETSID));
+
+  ProcStat ps = {};
+  GetChildStat(&sa, &ps);
+  ASSERT_NE(parent_sid, ps.sid);
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawn_POSIX_SPAWN_SETPGROUP_clear) {
+  pid_t parent_pgrp = getpgrp();
+
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, 0));
+
+  ProcStat ps = {};
+  GetChildStat(&sa, &ps);
+  ASSERT_EQ(parent_pgrp, ps.pgrp);
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawn_POSIX_SPAWN_SETPGROUP_set) {
+  pid_t parent_pgrp = getpgrp();
+
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+  ASSERT_EQ(0, posix_spawnattr_setpgroup(&sa, 0));
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, POSIX_SPAWN_SETPGROUP));
+
+  ProcStat ps = {};
+  GetChildStat(&sa, &ps);
+  ASSERT_NE(parent_pgrp, ps.pgrp);
+  // Setting pgid 0 means "the same as the caller's pid".
+  ASSERT_EQ(ps.pid, ps.pgrp);
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawn_POSIX_SPAWN_SETSIGMASK) {
+  // Block SIGBUS in the parent...
+  sigset_t just_SIGBUS;
+  sigemptyset(&just_SIGBUS);
+  sigaddset(&just_SIGBUS, SIGBUS);
+  ASSERT_EQ(0, sigprocmask(SIG_BLOCK, &just_SIGBUS, nullptr));
+
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  // Ask for only SIGALRM to be blocked in the child...
+  sigset_t just_SIGALRM;
+  sigemptyset(&just_SIGALRM);
+  sigaddset(&just_SIGALRM, SIGALRM);
+  ASSERT_EQ(0, posix_spawnattr_setsigmask(&sa, &just_SIGALRM));
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, POSIX_SPAWN_SETSIGMASK));
+
+  // Check that's what happens...
+  ProcStatus ps = {};
+  GetChildStatus(&sa, &ps);
+  EXPECT_EQ(static_cast<uint64_t>(1 << (SIGALRM - 1)), ps.sigblk);
+  EXPECT_EQ(static_cast<uint64_t>(0), ps.sigign);
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
+
+TEST(spawn, posix_spawn_POSIX_SPAWN_SETSIGDEF) {
+  // Ignore SIGALRM and SIGCONT in the parent...
+  ASSERT_NE(SIG_ERR, signal(SIGALRM, SIG_IGN));
+  ASSERT_NE(SIG_ERR, signal(SIGCONT, SIG_IGN));
+
+  posix_spawnattr_t sa;
+  ASSERT_EQ(0, posix_spawnattr_init(&sa));
+
+  // Ask for SIGALRM to be defaulted in the child...
+  sigset_t just_SIGALRM;
+  sigemptyset(&just_SIGALRM);
+  sigaddset(&just_SIGALRM, SIGALRM);
+  ASSERT_EQ(0, posix_spawnattr_setsigdefault(&sa, &just_SIGALRM));
+  ASSERT_EQ(0, posix_spawnattr_setflags(&sa, POSIX_SPAWN_SETSIGDEF));
+
+  // Check that's what happens...
+  ProcStatus ps = {};
+  GetChildStatus(&sa, &ps);
+  EXPECT_EQ(static_cast<uint64_t>(0), ps.sigblk);
+  EXPECT_EQ(static_cast<uint64_t>(1 << (SIGCONT - 1)), ps.sigign);
+
+  ASSERT_EQ(0, posix_spawnattr_destroy(&sa));
+}
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 9203215..ced0315 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -736,6 +736,7 @@
   EXPECT_GT(_POSIX_SEM_VALUE_MAX, 0);
   EXPECT_GT(_POSIX_SHELL, 0);
   EXPECT_GT(_POSIX_SIGQUEUE_MAX, 0);
+  EXPECT_EQ(_POSIX_VERSION, _POSIX_SPAWN);
   EXPECT_EQ(_POSIX_VERSION, _POSIX_SPORADIC_SERVER);
   EXPECT_GT(_POSIX_SSIZE_MAX, 0);
   EXPECT_GT(_POSIX_STREAM_MAX, 0);
@@ -791,7 +792,6 @@
   EXPECT_EQ(-1, _POSIX_MESSAGE_PASSING);
   EXPECT_EQ(-1, _POSIX_PRIORITIZED_IO);
   EXPECT_EQ(-1, _POSIX_SHARED_MEMORY_OBJECTS);
-  EXPECT_EQ(-1, _POSIX_SPAWN);
   EXPECT_EQ(-1, _POSIX_THREAD_ROBUST_PRIO_INHERIT);
 
   EXPECT_EQ(-1, _POSIX2_CHAR_TERM);
@@ -915,6 +915,7 @@
   VERIFY_SYSCONF_POSIX_VERSION(_SC_READER_WRITER_LOCKS);
   VERIFY_SYSCONF_POSITIVE(_SC_REGEXP);
   VERIFY_SYSCONF_POSITIVE(_SC_SHELL);
+  VERIFY_SYSCONF_POSIX_VERSION(_SC_SPAWN);
   VERIFY_SYSCONF_POSIX_VERSION(_SC_SPORADIC_SERVER);
   VERIFY_SYSCONF_POSITIVE(_SC_SYMLOOP_MAX);
   VERIFY_SYSCONF_POSIX_VERSION(_SC_THREAD_CPUTIME);
@@ -954,7 +955,6 @@
   VERIFY_SYSCONF_UNSUPPORTED(_SC_MESSAGE_PASSING);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_PRIORITIZED_IO);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_SHARED_MEMORY_OBJECTS);
-  VERIFY_SYSCONF_UNSUPPORTED(_SC_SPAWN);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_THREAD_ROBUST_PRIO_INHERIT);
   VERIFY_SYSCONF_UNSUPPORTED(_SC_THREAD_ROBUST_PRIO_PROTECT);
 
@@ -1212,12 +1212,6 @@
   }
 }
 
-#if defined(__GLIBC__)
-#define BIN_DIR "/bin/"
-#else
-#define BIN_DIR "/system/bin/"
-#endif
-
 TEST(UNISTD_TEST, execve_failure) {
   ExecTestHelper eth;
   errno = 0;
diff --git a/tests/utils.h b/tests/utils.h
index daf382e..ba006f1 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -38,6 +38,12 @@
 #define PATH_TO_SYSTEM_LIB "/system/lib/"
 #endif
 
+#if defined(__GLIBC__)
+#define BIN_DIR "/bin/"
+#else
+#define BIN_DIR "/system/bin/"
+#endif
+
 #if defined(__BIONIC__)
 #define KNOWN_FAILURE_ON_BIONIC(x) xfail_ ## x
 #else
@@ -159,6 +165,9 @@
   char** GetArgs() {
     return const_cast<char**>(args_.data());
   }
+  const char* GetArg0() {
+    return args_[0];
+  }
   char** GetEnv() {
     return const_cast<char**>(env_.data());
   }