Fix fibers gdb utils script

[folly.git] / folly / Subprocess.cpp

diff --git a/folly/Subprocess.cpp b/folly/Subprocess.cpp
index 17e997e6854537cb266611a8f453a1513c2e3aab..93e3f577157a1ad324411eaa3bafdc6ad1292b5f 100644 (file)
--- a/folly/Subprocess.cpp
+++ b/folly/Subprocess.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2016 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,9 +24,6 @@
 #include <sys/prctl.h>
 #endif
 #include <fcntl.h>
-#include <poll.h>
-
-#include <unistd.h>
 
 #include <array>
 #include <algorithm>
@@ -40,16 +37,30 @@
 #include <folly/Conv.h>
 #include <folly/Exception.h>
 #include <folly/ScopeGuard.h>
+#include <folly/Shell.h>
 #include <folly/String.h>
 #include <folly/io/Cursor.h>
-
-extern char** environ;
+#include <folly/portability/Environment.h>
+#include <folly/portability/Sockets.h>
+#include <folly/portability/Unistd.h>
 
 constexpr int kExecFailure = 127;
 constexpr int kChildFailure = 126;
 
 namespace folly {
 
+ProcessReturnCode::ProcessReturnCode(ProcessReturnCode&& p) noexcept
+  : rawStatus_(p.rawStatus_) {
+  p.rawStatus_ = ProcessReturnCode::RV_NOT_STARTED;
+}
+
+ProcessReturnCode& ProcessReturnCode::operator=(ProcessReturnCode&& p)
+    noexcept {
+  rawStatus_ = p.rawStatus_;
+  p.rawStatus_ = ProcessReturnCode::RV_NOT_STARTED;
+  return *this;
+}
+
 ProcessReturnCode::State ProcessReturnCode::state() const {
   if (rawStatus_ == RV_NOT_STARTED) return NOT_STARTED;
   if (rawStatus_ == RV_RUNNING) return RUNNING;
@@ -151,13 +162,13 @@ Subprocess::Options& Subprocess::Options::fd(int fd, int action) {
   return *this;
 }
 
+Subprocess::Subprocess() {}
+
 Subprocess::Subprocess(
     const std::vector<std::string>& argv,
     const Options& options,
     const char* executable,
-    const std::vector<std::string>* env)
-  : pid_(-1),
-    returnCode_(RV_NOT_STARTED) {
+    const std::vector<std::string>* env) {
   if (argv.empty()) {
     throw std::invalid_argument("argv must not be empty");
   }
@@ -168,23 +179,13 @@ Subprocess::Subprocess(
 Subprocess::Subprocess(
     const std::string& cmd,
     const Options& options,
-    const std::vector<std::string>* env)
-  : pid_(-1),
-    returnCode_(RV_NOT_STARTED) {
+    const std::vector<std::string>* env) {
   if (options.usePath_) {
     throw std::invalid_argument("usePath() not allowed when running in shell");
   }
-  const char* shell = getenv("SHELL");
-  if (!shell) {
-    shell = "/bin/sh";
-  }
 
-  std::unique_ptr<const char*[]> argv(new const char*[4]);
-  argv[0] = shell;
-  argv[1] = "-c";
-  argv[2] = cmd.c_str();
-  argv[3] = nullptr;
-  spawn(std::move(argv), shell, options, env);
+  std::vector<std::string> argv = {"/bin/sh", "-c", cmd};
+  spawn(cloneStrings(argv), argv[0].c_str(), options, env);
 }
 
 Subprocess::~Subprocess() {
@@ -199,8 +200,7 @@ struct ChildErrorInfo {
   int errnoValue;
 };
 
-FOLLY_NORETURN void childError(int errFd, int errCode, int errnoValue);
-void childError(int errFd, int errCode, int errnoValue) {
+[[noreturn]] void childError(int errFd, int errCode, int errnoValue) {
   ChildErrorInfo info = {errCode, errnoValue};
   // Write the error information over the pipe to our parent process.
   // We can't really do anything else if this write call fails.
@@ -469,7 +469,9 @@ int Subprocess::prepareChild(const Options& options,
 #if __linux__
   // Opt to receive signal on parent death, if requested
   if (options.parentDeathSignal_ != 0) {
-    if (prctl(PR_SET_PDEATHSIG, options.parentDeathSignal_, 0, 0, 0) == -1) {
+    const auto parentDeathSignal =
+        static_cast<unsigned long>(options.parentDeathSignal_);
+    if (prctl(PR_SET_PDEATHSIG, parentDeathSignal, 0, 0, 0) == -1) {
       return errno;
     }
   }
@@ -481,6 +483,13 @@ int Subprocess::prepareChild(const Options& options,
     }
   }
 
+  // The user callback comes last, so that the child is otherwise all set up.
+  if (options.dangerousPostForkPreExecCallback_) {
+    if (int error = (*options.dangerousPostForkPreExecCallback_)()) {
+      return error;
+    }
+  }
+
   return 0;
 }
 
@@ -530,7 +539,10 @@ ProcessReturnCode Subprocess::poll() {
   DCHECK_GT(pid_, 0);
   int status;
   pid_t found = ::waitpid(pid_, &status, WNOHANG);
-  checkUnixError(found, "waitpid");
+  // The spec guarantees that EINTR does not occur with WNOHANG, so the only
+  // two remaining errors are ECHILD (other code reaped the child?), or
+  // EINVAL (cosmic rays?), both of which merit an abort:
+  PCHECK(found != -1) << "waitpid(" << pid_ << ", &status, WNOHANG)";
   if (found != 0) {
     // Though the child process had quit, this call does not close the pipes
     // since its descendants may still be using them.
@@ -556,7 +568,9 @@ ProcessReturnCode Subprocess::wait() {
   do {
     found = ::waitpid(pid_, &status, 0);
   } while (found == -1 && errno == EINTR);
-  checkUnixError(found, "waitpid");
+  // The only two remaining errors are ECHILD (other code reaped the
+  // child?), or EINVAL (cosmic rays?), and both merit an abort:
+  PCHECK(found != -1) << "waitpid(" << pid_ << ", &status, WNOHANG)";
   // Though the child process had quit, this call does not close the pipes
   // since its descendants may still be using them.
   DCHECK_EQ(found, pid_);
@@ -582,21 +596,23 @@ pid_t Subprocess::pid() const {
 
 namespace {
 
-std::pair<const uint8_t*, size_t> queueFront(const IOBufQueue& queue) {
+ByteRange queueFront(const IOBufQueue& queue) {
   auto* p = queue.front();
-  if (!p) return std::make_pair(nullptr, 0);
-  return io::Cursor(p).peek();
+  if (!p) {
+    return ByteRange{};
+  }
+  return io::Cursor(p).peekBytes();
 }
 
 // fd write
 bool handleWrite(int fd, IOBufQueue& queue) {
   for (;;) {
-    auto p = queueFront(queue);
-    if (p.second == 0) {
+    auto b = queueFront(queue);
+    if (b.empty()) {
       return true;  // EOF
     }
 
-    ssize_t n = writeNoInt(fd, p.first, p.second);
+    ssize_t n = writeNoInt(fd, b.data(), b.size());
     if (n == -1 && errno == EAGAIN) {
       return false;
     }
@@ -807,9 +823,10 @@ void Subprocess::closeParentFd(int childFd) {
 std::vector<Subprocess::ChildPipe> Subprocess::takeOwnershipOfPipes() {
   std::vector<Subprocess::ChildPipe> pipes;
   for (auto& p : pipes_) {
-    pipes.emplace_back(ChildPipe{p.childFd, std::move(p.pipe)});
+    pipes.emplace_back(p.childFd, std::move(p.pipe));
   }
-  pipes_.clear();
+  // release memory
+  std::vector<Pipe>().swap(pipes_);
   return pipes;
 }