forked from OSchip/llvm-project
431 lines
12 KiB
C++
431 lines
12 KiB
C++
//===- llvm/Support/Unix/Program.cpp -----------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the Unix specific portion of the Program class.
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//
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//===----------------------------------------------------------------------===//
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only generic UNIX code that
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//=== is guaranteed to work on *all* UNIX variants.
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//===----------------------------------------------------------------------===//
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#include "Unix.h"
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#include "llvm/Support/FileSystem.h"
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#include <llvm/Config/config.h>
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#if HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#if HAVE_SYS_RESOURCE_H
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#include <sys/resource.h>
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#endif
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#if HAVE_SIGNAL_H
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#include <signal.h>
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#endif
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#if HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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#ifdef HAVE_POSIX_SPAWN
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#include <spawn.h>
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#if !defined(__APPLE__)
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extern char **environ;
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#else
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#include <crt_externs.h> // _NSGetEnviron
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#endif
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#endif
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namespace llvm {
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using namespace sys;
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Program::Program() : Data_(0) {}
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Program::~Program() {}
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unsigned Program::GetPid() const {
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uint64_t pid = reinterpret_cast<uint64_t>(Data_);
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return static_cast<unsigned>(pid);
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}
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// This function just uses the PATH environment variable to find the program.
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Path
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Program::FindProgramByName(const std::string& progName) {
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// Check some degenerate cases
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if (progName.length() == 0) // no program
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return Path();
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Path temp;
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if (!temp.set(progName)) // invalid name
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return Path();
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// Use the given path verbatim if it contains any slashes; this matches
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// the behavior of sh(1) and friends.
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if (progName.find('/') != std::string::npos)
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return temp;
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// At this point, the file name is valid and does not contain slashes. Search
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// for it through the directories specified in the PATH environment variable.
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// Get the path. If its empty, we can't do anything to find it.
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const char *PathStr = getenv("PATH");
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if (PathStr == 0)
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return Path();
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// Now we have a colon separated list of directories to search; try them.
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size_t PathLen = strlen(PathStr);
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while (PathLen) {
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// Find the first colon...
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const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
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// Check to see if this first directory contains the executable...
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Path FilePath;
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if (FilePath.set(std::string(PathStr,Colon))) {
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FilePath.appendComponent(progName);
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if (FilePath.canExecute())
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return FilePath; // Found the executable!
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}
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// Nope it wasn't in this directory, check the next path in the list!
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PathLen -= Colon-PathStr;
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PathStr = Colon;
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// Advance past duplicate colons
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while (*PathStr == ':') {
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PathStr++;
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PathLen--;
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}
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}
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return Path();
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}
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static bool RedirectIO(const Path *Path, int FD, std::string* ErrMsg) {
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if (Path == 0) // Noop
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return false;
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const char *File;
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if (Path->isEmpty())
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// Redirect empty paths to /dev/null
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File = "/dev/null";
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else
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File = Path->c_str();
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// Open the file
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int InFD = open(File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
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if (InFD == -1) {
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MakeErrMsg(ErrMsg, "Cannot open file '" + std::string(File) + "' for "
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+ (FD == 0 ? "input" : "output"));
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return true;
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}
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// Install it as the requested FD
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if (dup2(InFD, FD) == -1) {
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MakeErrMsg(ErrMsg, "Cannot dup2");
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close(InFD);
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return true;
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}
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close(InFD); // Close the original FD
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return false;
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}
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#ifdef HAVE_POSIX_SPAWN
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static bool RedirectIO_PS(const Path *Path, int FD, std::string *ErrMsg,
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posix_spawn_file_actions_t *FileActions) {
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if (Path == 0) // Noop
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return false;
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const char *File;
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if (Path->isEmpty())
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// Redirect empty paths to /dev/null
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File = "/dev/null";
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else
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File = Path->c_str();
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if (int Err = posix_spawn_file_actions_addopen(FileActions, FD,
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File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666))
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return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
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return false;
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}
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#endif
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static void TimeOutHandler(int Sig) {
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}
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static void SetMemoryLimits (unsigned size)
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{
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#if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
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struct rlimit r;
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__typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
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// Heap size
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getrlimit (RLIMIT_DATA, &r);
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r.rlim_cur = limit;
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setrlimit (RLIMIT_DATA, &r);
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#ifdef RLIMIT_RSS
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// Resident set size.
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getrlimit (RLIMIT_RSS, &r);
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r.rlim_cur = limit;
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setrlimit (RLIMIT_RSS, &r);
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#endif
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#ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
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// Virtual memory.
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getrlimit (RLIMIT_AS, &r);
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r.rlim_cur = limit;
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setrlimit (RLIMIT_AS, &r);
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#endif
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#endif
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}
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bool
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Program::Execute(const Path &path, const char **args, const char **envp,
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const Path **redirects, unsigned memoryLimit,
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std::string *ErrMsg) {
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// If this OS has posix_spawn and there is no memory limit being implied, use
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// posix_spawn. It is more efficient than fork/exec.
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#ifdef HAVE_POSIX_SPAWN
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if (memoryLimit == 0) {
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posix_spawn_file_actions_t FileActionsStore;
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posix_spawn_file_actions_t *FileActions = 0;
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if (redirects) {
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FileActions = &FileActionsStore;
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posix_spawn_file_actions_init(FileActions);
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// Redirect stdin/stdout.
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if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) ||
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RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions))
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return false;
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if (redirects[1] == 0 || redirects[2] == 0 ||
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*redirects[1] != *redirects[2]) {
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// Just redirect stderr
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if (RedirectIO_PS(redirects[2], 2, ErrMsg, FileActions)) return false;
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} else {
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// If stdout and stderr should go to the same place, redirect stderr
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// to the FD already open for stdout.
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if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
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return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
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}
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}
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if (!envp)
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#if !defined(__APPLE__)
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envp = const_cast<const char **>(environ);
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#else
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// environ is missing in dylibs.
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envp = const_cast<const char **>(*_NSGetEnviron());
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#endif
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// Explicitly initialized to prevent what appears to be a valgrind false
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// positive.
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pid_t PID = 0;
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int Err = posix_spawn(&PID, path.c_str(), FileActions, /*attrp*/0,
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const_cast<char **>(args), const_cast<char **>(envp));
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if (FileActions)
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posix_spawn_file_actions_destroy(FileActions);
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if (Err)
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return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
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Data_ = reinterpret_cast<void*>(PID);
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return true;
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}
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#endif
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// Create a child process.
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int child = fork();
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switch (child) {
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// An error occurred: Return to the caller.
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case -1:
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MakeErrMsg(ErrMsg, "Couldn't fork");
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return false;
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// Child process: Execute the program.
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case 0: {
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// Redirect file descriptors...
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if (redirects) {
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// Redirect stdin
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if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
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// Redirect stdout
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if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
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if (redirects[1] && redirects[2] &&
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*(redirects[1]) == *(redirects[2])) {
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// If stdout and stderr should go to the same place, redirect stderr
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// to the FD already open for stdout.
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if (-1 == dup2(1,2)) {
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MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
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return false;
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}
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} else {
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// Just redirect stderr
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if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
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}
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}
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// Set memory limits
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if (memoryLimit!=0) {
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SetMemoryLimits(memoryLimit);
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}
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// Execute!
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if (envp != 0)
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execve(path.c_str(),
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const_cast<char **>(args),
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const_cast<char **>(envp));
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else
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execv(path.c_str(),
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const_cast<char **>(args));
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// If the execve() failed, we should exit. Follow Unix protocol and
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// return 127 if the executable was not found, and 126 otherwise.
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// Use _exit rather than exit so that atexit functions and static
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// object destructors cloned from the parent process aren't
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// redundantly run, and so that any data buffered in stdio buffers
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// cloned from the parent aren't redundantly written out.
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_exit(errno == ENOENT ? 127 : 126);
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}
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// Parent process: Break out of the switch to do our processing.
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default:
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break;
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}
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Data_ = reinterpret_cast<void*>(child);
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return true;
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}
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int
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Program::Wait(const sys::Path &path,
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unsigned secondsToWait,
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std::string* ErrMsg)
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{
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#ifdef HAVE_SYS_WAIT_H
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struct sigaction Act, Old;
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if (Data_ == 0) {
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MakeErrMsg(ErrMsg, "Process not started!");
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return -1;
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}
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// Install a timeout handler. The handler itself does nothing, but the simple
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// fact of having a handler at all causes the wait below to return with EINTR,
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// unlike if we used SIG_IGN.
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if (secondsToWait) {
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memset(&Act, 0, sizeof(Act));
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Act.sa_handler = TimeOutHandler;
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sigemptyset(&Act.sa_mask);
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sigaction(SIGALRM, &Act, &Old);
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alarm(secondsToWait);
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}
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// Parent process: Wait for the child process to terminate.
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int status;
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uint64_t pid = reinterpret_cast<uint64_t>(Data_);
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pid_t child = static_cast<pid_t>(pid);
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while (waitpid(pid, &status, 0) != child)
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if (secondsToWait && errno == EINTR) {
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// Kill the child.
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kill(child, SIGKILL);
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// Turn off the alarm and restore the signal handler
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alarm(0);
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sigaction(SIGALRM, &Old, 0);
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// Wait for child to die
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if (wait(&status) != child)
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MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
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else
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MakeErrMsg(ErrMsg, "Child timed out", 0);
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return -2; // Timeout detected
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} else if (errno != EINTR) {
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MakeErrMsg(ErrMsg, "Error waiting for child process");
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return -1;
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}
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// We exited normally without timeout, so turn off the timer.
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if (secondsToWait) {
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alarm(0);
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sigaction(SIGALRM, &Old, 0);
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}
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// Return the proper exit status. Detect error conditions
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// so we can return -1 for them and set ErrMsg informatively.
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int result = 0;
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if (WIFEXITED(status)) {
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result = WEXITSTATUS(status);
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#ifdef HAVE_POSIX_SPAWN
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// The posix_spawn child process returns 127 on any kind of error.
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// Following the POSIX convention for command-line tools (which posix_spawn
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// itself apparently does not), check to see if the failure was due to some
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// reason other than the file not existing, and return 126 in this case.
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bool Exists;
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if (result == 127 && !llvm::sys::fs::exists(path.str(), Exists) && Exists)
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result = 126;
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#endif
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if (result == 127) {
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if (ErrMsg)
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*ErrMsg = llvm::sys::StrError(ENOENT);
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return -1;
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}
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if (result == 126) {
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if (ErrMsg)
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*ErrMsg = "Program could not be executed";
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return -1;
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}
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} else if (WIFSIGNALED(status)) {
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if (ErrMsg) {
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*ErrMsg = strsignal(WTERMSIG(status));
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#ifdef WCOREDUMP
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if (WCOREDUMP(status))
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*ErrMsg += " (core dumped)";
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#endif
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}
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// Return a special value to indicate that the process received an unhandled
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// signal during execution as opposed to failing to execute.
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return -2;
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}
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return result;
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#else
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if (ErrMsg)
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*ErrMsg = "Program::Wait is not implemented on this platform yet!";
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return -1;
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#endif
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}
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bool
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Program::Kill(std::string* ErrMsg) {
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if (Data_ == 0) {
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MakeErrMsg(ErrMsg, "Process not started!");
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return true;
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}
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uint64_t pid64 = reinterpret_cast<uint64_t>(Data_);
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pid_t pid = static_cast<pid_t>(pid64);
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if (kill(pid, SIGKILL) != 0) {
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MakeErrMsg(ErrMsg, "The process couldn't be killed!");
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return true;
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}
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return false;
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}
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error_code Program::ChangeStdinToBinary(){
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// Do nothing, as Unix doesn't differentiate between text and binary.
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return make_error_code(errc::success);
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}
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error_code Program::ChangeStdoutToBinary(){
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// Do nothing, as Unix doesn't differentiate between text and binary.
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return make_error_code(errc::success);
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}
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error_code Program::ChangeStderrToBinary(){
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// Do nothing, as Unix doesn't differentiate between text and binary.
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return make_error_code(errc::success);
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}
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}
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