1 files changed, 500 insertions, 0 deletions
diff --git a/llvm/lib/Support/Unix/Program.inc b/llvm/lib/Support/Unix/Program.inc
new file mode 100644
index 000000000000..520685a0e987
--- /dev/null
+++ b/llvm/lib/Support/Unix/Program.inc
@@ -0,0 +1,500 @@
+//===- llvm/Support/Unix/Program.cpp -----------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Unix specific portion of the Program class.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only generic UNIX code that
+//===          is guaranteed to work on *all* UNIX variants.
+//===----------------------------------------------------------------------===//
+
+#include "Unix.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/StringSaver.h"
+#include "llvm/Support/raw_ostream.h"
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+#if HAVE_SIGNAL_H
+#include <signal.h>
+#endif
+#if HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#ifdef HAVE_POSIX_SPAWN
+#include <spawn.h>
+
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+
+#if defined(__APPLE__) && !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE)
+#define USE_NSGETENVIRON 1
+#else
+#define USE_NSGETENVIRON 0
+#endif
+
+#if !USE_NSGETENVIRON
+  extern char **environ;
+#else
+#include <crt_externs.h> // _NSGetEnviron
+#endif
+#endif
+
+namespace llvm {
+
+using namespace sys;
+
+ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
+
+ErrorOr<std::string> sys::findProgramByName(StringRef Name,
+                                            ArrayRef<StringRef> Paths) {
+  assert(!Name.empty() && "Must have a name!");
+  // Use the given path verbatim if it contains any slashes; this matches
+  // the behavior of sh(1) and friends.
+  if (Name.find('/') != StringRef::npos)
+    return std::string(Name);
+
+  SmallVector<StringRef, 16> EnvironmentPaths;
+  if (Paths.empty())
+    if (const char *PathEnv = std::getenv("PATH")) {
+      SplitString(PathEnv, EnvironmentPaths, ":");
+      Paths = EnvironmentPaths;
+    }
+
+  for (auto Path : Paths) {
+    if (Path.empty())
+      continue;
+
+    // Check to see if this first directory contains the executable...
+    SmallString<128> FilePath(Path);
+    sys::path::append(FilePath, Name);
+    if (sys::fs::can_execute(FilePath.c_str()))
+      return std::string(FilePath.str()); // Found the executable!
+  }
+  return errc::no_such_file_or_directory;
+}
+
+static bool RedirectIO(Optional<StringRef> Path, int FD, std::string* ErrMsg) {
+  if (!Path) // Noop
+    return false;
+  std::string File;
+  if (Path->empty())
+    // Redirect empty paths to /dev/null
+    File = "/dev/null";
+  else
+    File = *Path;
+
+  // Open the file
+  int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
+  if (InFD == -1) {
+    MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
+              + (FD == 0 ? "input" : "output"));
+    return true;
+  }
+
+  // Install it as the requested FD
+  if (dup2(InFD, FD) == -1) {
+    MakeErrMsg(ErrMsg, "Cannot dup2");
+    close(InFD);
+    return true;
+  }
+  close(InFD);      // Close the original FD
+  return false;
+}
+
+#ifdef HAVE_POSIX_SPAWN
+static bool RedirectIO_PS(const std::string *Path, int FD, std::string *ErrMsg,
+                          posix_spawn_file_actions_t *FileActions) {
+  if (!Path) // Noop
+    return false;
+  const char *File;
+  if (Path->empty())
+    // Redirect empty paths to /dev/null
+    File = "/dev/null";
+  else
+    File = Path->c_str();
+
+  if (int Err = posix_spawn_file_actions_addopen(
+          FileActions, FD, File,
+          FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
+    return MakeErrMsg(ErrMsg, "Cannot posix_spawn_file_actions_addopen", Err);
+  return false;
+}
+#endif
+
+static void TimeOutHandler(int Sig) {
+}
+
+static void SetMemoryLimits(unsigned size) {
+#if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
+  struct rlimit r;
+  __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
+
+  // Heap size
+  getrlimit (RLIMIT_DATA, &r);
+  r.rlim_cur = limit;
+  setrlimit (RLIMIT_DATA, &r);
+#ifdef RLIMIT_RSS
+  // Resident set size.
+  getrlimit (RLIMIT_RSS, &r);
+  r.rlim_cur = limit;
+  setrlimit (RLIMIT_RSS, &r);
+#endif
+#endif
+}
+
+}
+
+static std::vector<const char *>
+toNullTerminatedCStringArray(ArrayRef<StringRef> Strings, StringSaver &Saver) {
+  std::vector<const char *> Result;
+  for (StringRef S : Strings)
+    Result.push_back(Saver.save(S).data());
+  Result.push_back(nullptr);
+  return Result;
+}
+
+static bool Execute(ProcessInfo &PI, StringRef Program,
+                    ArrayRef<StringRef> Args, Optional<ArrayRef<StringRef>> Env,
+                    ArrayRef<Optional<StringRef>> Redirects,
+                    unsigned MemoryLimit, std::string *ErrMsg) {
+  if (!llvm::sys::fs::exists(Program)) {
+    if (ErrMsg)
+      *ErrMsg = std::string("Executable \"") + Program.str() +
+                std::string("\" doesn't exist!");
+    return false;
+  }
+
+  BumpPtrAllocator Allocator;
+  StringSaver Saver(Allocator);
+  std::vector<const char *> ArgVector, EnvVector;
+  const char **Argv = nullptr;
+  const char **Envp = nullptr;
+  ArgVector = toNullTerminatedCStringArray(Args, Saver);
+  Argv = ArgVector.data();
+  if (Env) {
+    EnvVector = toNullTerminatedCStringArray(*Env, Saver);
+    Envp = EnvVector.data();
+  }
+
+  // If this OS has posix_spawn and there is no memory limit being implied, use
+  // posix_spawn.  It is more efficient than fork/exec.
+#ifdef HAVE_POSIX_SPAWN
+  if (MemoryLimit == 0) {
+    posix_spawn_file_actions_t FileActionsStore;
+    posix_spawn_file_actions_t *FileActions = nullptr;
+
+    // If we call posix_spawn_file_actions_addopen we have to make sure the
+    // c strings we pass to it stay alive until the call to posix_spawn,
+    // so we copy any StringRefs into this variable.
+    std::string RedirectsStorage[3];
+
+    if (!Redirects.empty()) {
+      assert(Redirects.size() == 3);
+      std::string *RedirectsStr[3] = {nullptr, nullptr, nullptr};
+      for (int I = 0; I < 3; ++I) {
+        if (Redirects[I]) {
+          RedirectsStorage[I] = *Redirects[I];
+          RedirectsStr[I] = &RedirectsStorage[I];
+        }
+      }
+
+      FileActions = &FileActionsStore;
+      posix_spawn_file_actions_init(FileActions);
+
+      // Redirect stdin/stdout.
+      if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
+          RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
+        return false;
+      if (!Redirects[1] || !Redirects[2] || *Redirects[1] != *Redirects[2]) {
+        // Just redirect stderr
+        if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
+          return false;
+      } else {
+        // If stdout and stderr should go to the same place, redirect stderr
+        // to the FD already open for stdout.
+        if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
+          return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
+      }
+    }
+
+    if (!Envp)
+#if !USE_NSGETENVIRON
+      Envp = const_cast<const char **>(environ);
+#else
+      // environ is missing in dylibs.
+      Envp = const_cast<const char **>(*_NSGetEnviron());
+#endif
+
+    constexpr int maxRetries = 8;
+    int retries = 0;
+    pid_t PID;
+    int Err;
+    do {
+      PID = 0; // Make Valgrind happy.
+      Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
+                        /*attrp*/ nullptr, const_cast<char **>(Argv),
+                        const_cast<char **>(Envp));
+    } while (Err == EINTR && ++retries < maxRetries);
+
+    if (FileActions)
+      posix_spawn_file_actions_destroy(FileActions);
+
+    if (Err)
+     return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
+
+    PI.Pid = PID;
+    PI.Process = PID;
+
+    return true;
+  }
+#endif
+
+  // Create a child process.
+  int child = fork();
+  switch (child) {
+    // An error occurred:  Return to the caller.
+    case -1:
+      MakeErrMsg(ErrMsg, "Couldn't fork");
+      return false;
+
+    // Child process: Execute the program.
+    case 0: {
+      // Redirect file descriptors...
+      if (!Redirects.empty()) {
+        // Redirect stdin
+        if (RedirectIO(Redirects[0], 0, ErrMsg)) { return false; }
+        // Redirect stdout
+        if (RedirectIO(Redirects[1], 1, ErrMsg)) { return false; }
+        if (Redirects[1] && Redirects[2] && *Redirects[1] == *Redirects[2]) {
+          // If stdout and stderr should go to the same place, redirect stderr
+          // to the FD already open for stdout.
+          if (-1 == dup2(1,2)) {
+            MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
+            return false;
+          }
+        } else {
+          // Just redirect stderr
+          if (RedirectIO(Redirects[2], 2, ErrMsg)) { return false; }
+        }
+      }
+
+      // Set memory limits
+      if (MemoryLimit!=0) {
+        SetMemoryLimits(MemoryLimit);
+      }
+
+      // Execute!
+      std::string PathStr = Program;
+      if (Envp != nullptr)
+        execve(PathStr.c_str(), const_cast<char **>(Argv),
+               const_cast<char **>(Envp));
+      else
+        execv(PathStr.c_str(), const_cast<char **>(Argv));
+      // If the execve() failed, we should exit. Follow Unix protocol and
+      // return 127 if the executable was not found, and 126 otherwise.
+      // Use _exit rather than exit so that atexit functions and static
+      // object destructors cloned from the parent process aren't
+      // redundantly run, and so that any data buffered in stdio buffers
+      // cloned from the parent aren't redundantly written out.
+      _exit(errno == ENOENT ? 127 : 126);
+    }
+
+    // Parent process: Break out of the switch to do our processing.
+    default:
+      break;
+  }
+
+  PI.Pid = child;
+  PI.Process = child;
+
+  return true;
+}
+
+namespace llvm {
+
+ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
+                      bool WaitUntilTerminates, std::string *ErrMsg) {
+  struct sigaction Act, Old;
+  assert(PI.Pid && "invalid pid to wait on, process not started?");
+
+  int WaitPidOptions = 0;
+  pid_t ChildPid = PI.Pid;
+  if (WaitUntilTerminates) {
+    SecondsToWait = 0;
+  } else if (SecondsToWait) {
+    // Install a timeout handler.  The handler itself does nothing, but the
+    // simple fact of having a handler at all causes the wait below to return
+    // with EINTR, unlike if we used SIG_IGN.
+    memset(&Act, 0, sizeof(Act));
+    Act.sa_handler = TimeOutHandler;
+    sigemptyset(&Act.sa_mask);
+    sigaction(SIGALRM, &Act, &Old);
+    alarm(SecondsToWait);
+  } else if (SecondsToWait == 0)
+    WaitPidOptions = WNOHANG;
+
+  // Parent process: Wait for the child process to terminate.
+  int status;
+  ProcessInfo WaitResult;
+
+  do {
+    WaitResult.Pid = waitpid(ChildPid, &status, WaitPidOptions);
+  } while (WaitUntilTerminates && WaitResult.Pid == -1 && errno == EINTR);
+
+  if (WaitResult.Pid != PI.Pid) {
+    if (WaitResult.Pid == 0) {
+      // Non-blocking wait.
+      return WaitResult;
+    } else {
+      if (SecondsToWait && errno == EINTR) {
+        // Kill the child.
+        kill(PI.Pid, SIGKILL);
+
+        // Turn off the alarm and restore the signal handler
+        alarm(0);
+        sigaction(SIGALRM, &Old, nullptr);
+
+        // Wait for child to die
+        if (wait(&status) != ChildPid)
+          MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
+        else
+          MakeErrMsg(ErrMsg, "Child timed out", 0);
+
+        WaitResult.ReturnCode = -2; // Timeout detected
+        return WaitResult;
+      } else if (errno != EINTR) {
+        MakeErrMsg(ErrMsg, "Error waiting for child process");
+        WaitResult.ReturnCode = -1;
+        return WaitResult;
+      }
+    }
+  }
+
+  // We exited normally without timeout, so turn off the timer.
+  if (SecondsToWait && !WaitUntilTerminates) {
+    alarm(0);
+    sigaction(SIGALRM, &Old, nullptr);
+  }
+
+  // Return the proper exit status. Detect error conditions
+  // so we can return -1 for them and set ErrMsg informatively.
+  int result = 0;
+  if (WIFEXITED(status)) {
+    result = WEXITSTATUS(status);
+    WaitResult.ReturnCode = result;
+
+    if (result == 127) {
+      if (ErrMsg)
+        *ErrMsg = llvm::sys::StrError(ENOENT);
+      WaitResult.ReturnCode = -1;
+      return WaitResult;
+    }
+    if (result == 126) {
+      if (ErrMsg)
+        *ErrMsg = "Program could not be executed";
+      WaitResult.ReturnCode = -1;
+      return WaitResult;
+    }
+  } else if (WIFSIGNALED(status)) {
+    if (ErrMsg) {
+      *ErrMsg = strsignal(WTERMSIG(status));
+#ifdef WCOREDUMP
+      if (WCOREDUMP(status))
+        *ErrMsg += " (core dumped)";
+#endif
+    }
+    // Return a special value to indicate that the process received an unhandled
+    // signal during execution as opposed to failing to execute.
+    WaitResult.ReturnCode = -2;
+  }
+  return WaitResult;
+}
+
+std::error_code sys::ChangeStdinToBinary() {
+  // Do nothing, as Unix doesn't differentiate between text and binary.
+  return std::error_code();
+}
+
+std::error_code sys::ChangeStdoutToBinary() {
+  // Do nothing, as Unix doesn't differentiate between text and binary.
+  return std::error_code();
+}
+
+std::error_code
+llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
+                                 WindowsEncodingMethod Encoding /*unused*/) {
+  std::error_code EC;
+  llvm::raw_fd_ostream OS(FileName, EC, llvm::sys::fs::OpenFlags::OF_Text);
+
+  if (EC)
+    return EC;
+
+  OS << Contents;
+
+  if (OS.has_error())
+    return make_error_code(errc::io_error);
+
+  return EC;
+}
+
+bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
+                                                  ArrayRef<StringRef> Args) {
+  static long ArgMax = sysconf(_SC_ARG_MAX);
+  // POSIX requires that _POSIX_ARG_MAX is 4096, which is the lowest possible
+  // value for ARG_MAX on a POSIX compliant system.
+  static long ArgMin = _POSIX_ARG_MAX;
+
+  // This the same baseline used by xargs.
+  long EffectiveArgMax = 128 * 1024;
+
+  if (EffectiveArgMax > ArgMax)
+    EffectiveArgMax = ArgMax;
+  else if (EffectiveArgMax < ArgMin)
+    EffectiveArgMax = ArgMin;
+
+  // System says no practical limit.
+  if (ArgMax == -1)
+    return true;
+
+  // Conservatively account for space required by environment variables.
+  long HalfArgMax = EffectiveArgMax / 2;
+
+  size_t ArgLength = Program.size() + 1;
+  for (StringRef Arg : Args) {
+    // Ensure that we do not exceed the MAX_ARG_STRLEN constant on Linux, which
+    // does not have a constant unlike what the man pages would have you
+    // believe. Since this limit is pretty high, perform the check
+    // unconditionally rather than trying to be aggressive and limiting it to
+    // Linux only.
+    if (Arg.size() >= (32 * 4096))
+      return false;
+
+    ArgLength += Arg.size() + 1;
+    if (ArgLength > size_t(HalfArgMax)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+}