1 //===- llvm/Support/Unix/Program.cpp -----------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Unix specific portion of the Program class.
12 //===----------------------------------------------------------------------===//
14 //===----------------------------------------------------------------------===//
15 //=== WARNING: Implementation here must contain only generic UNIX code that
16 //=== is guaranteed to work on *all* UNIX variants.
17 //===----------------------------------------------------------------------===//
20 #include "llvm/ADT/StringExtras.h"
21 #include "llvm/Config/config.h"
22 #include "llvm/Support/Compiler.h"
23 #include "llvm/Support/FileSystem.h"
24 #include "llvm/Support/Path.h"
25 #include "llvm/Support/raw_ostream.h"
29 #if HAVE_SYS_RESOURCE_H
30 #include <sys/resource.h>
41 #ifdef HAVE_POSIX_SPAWN
43 #define _RESTRICT_KYWD
47 #if defined(__APPLE__)
48 #include <TargetConditionals.h>
51 #if defined(__APPLE__) && !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE)
52 #define USE_NSGETENVIRON 1
54 #define USE_NSGETENVIRON 0
58 extern char **environ;
60 #include <crt_externs.h> // _NSGetEnviron
68 ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
70 ErrorOr<std::string> sys::findProgramByName(StringRef Name,
71 ArrayRef<StringRef> Paths) {
72 assert(!Name.empty() && "Must have a name!");
73 // Use the given path verbatim if it contains any slashes; this matches
74 // the behavior of sh(1) and friends.
75 if (Name.find('/') != StringRef::npos)
76 return std::string(Name);
78 SmallVector<StringRef, 16> EnvironmentPaths;
80 if (const char *PathEnv = std::getenv("PATH")) {
81 SplitString(PathEnv, EnvironmentPaths, ":");
82 Paths = EnvironmentPaths;
85 for (auto Path : Paths) {
89 // Check to see if this first directory contains the executable...
90 SmallString<128> FilePath(Path);
91 sys::path::append(FilePath, Name);
92 if (sys::fs::can_execute(FilePath.c_str()))
93 return std::string(FilePath.str()); // Found the executable!
95 return std::errc::no_such_file_or_directory;
98 static bool RedirectIO(const StringRef *Path, int FD, std::string* ErrMsg) {
103 // Redirect empty paths to /dev/null
109 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
111 MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
112 + (FD == 0 ? "input" : "output"));
116 // Install it as the requested FD
117 if (dup2(InFD, FD) == -1) {
118 MakeErrMsg(ErrMsg, "Cannot dup2");
122 close(InFD); // Close the original FD
126 #ifdef HAVE_POSIX_SPAWN
127 static bool RedirectIO_PS(const std::string *Path, int FD, std::string *ErrMsg,
128 posix_spawn_file_actions_t *FileActions) {
133 // Redirect empty paths to /dev/null
136 File = Path->c_str();
138 if (int Err = posix_spawn_file_actions_addopen(
139 FileActions, FD, File,
140 FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
141 return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
146 static void TimeOutHandler(int Sig) {
149 static void SetMemoryLimits (unsigned size)
151 #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
153 __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
156 getrlimit (RLIMIT_DATA, &r);
158 setrlimit (RLIMIT_DATA, &r);
160 // Resident set size.
161 getrlimit (RLIMIT_RSS, &r);
163 setrlimit (RLIMIT_RSS, &r);
165 #ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
166 // Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
167 // of virtual memory for shadow memory mapping.
168 #if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
170 getrlimit (RLIMIT_AS, &r);
172 setrlimit (RLIMIT_AS, &r);
180 static bool Execute(ProcessInfo &PI, StringRef Program, const char **args,
181 const char **envp, const StringRef **redirects,
182 unsigned memoryLimit, std::string *ErrMsg) {
183 if (!llvm::sys::fs::exists(Program)) {
185 *ErrMsg = std::string("Executable \"") + Program.str() +
186 std::string("\" doesn't exist!");
190 // If this OS has posix_spawn and there is no memory limit being implied, use
191 // posix_spawn. It is more efficient than fork/exec.
192 #ifdef HAVE_POSIX_SPAWN
193 if (memoryLimit == 0) {
194 posix_spawn_file_actions_t FileActionsStore;
195 posix_spawn_file_actions_t *FileActions = nullptr;
197 // If we call posix_spawn_file_actions_addopen we have to make sure the
198 // c strings we pass to it stay alive until the call to posix_spawn,
199 // so we copy any StringRefs into this variable.
200 std::string RedirectsStorage[3];
203 std::string *RedirectsStr[3] = {nullptr, nullptr, nullptr};
204 for (int I = 0; I < 3; ++I) {
206 RedirectsStorage[I] = *redirects[I];
207 RedirectsStr[I] = &RedirectsStorage[I];
211 FileActions = &FileActionsStore;
212 posix_spawn_file_actions_init(FileActions);
214 // Redirect stdin/stdout.
215 if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
216 RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
218 if (redirects[1] == nullptr || redirects[2] == nullptr ||
219 *redirects[1] != *redirects[2]) {
220 // Just redirect stderr
221 if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
224 // If stdout and stderr should go to the same place, redirect stderr
225 // to the FD already open for stdout.
226 if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
227 return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
232 #if !USE_NSGETENVIRON
233 envp = const_cast<const char **>(environ);
235 // environ is missing in dylibs.
236 envp = const_cast<const char **>(*_NSGetEnviron());
239 // Explicitly initialized to prevent what appears to be a valgrind false
242 int Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
243 /*attrp*/nullptr, const_cast<char **>(args),
244 const_cast<char **>(envp));
247 posix_spawn_file_actions_destroy(FileActions);
250 return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
258 // Create a child process.
261 // An error occurred: Return to the caller.
263 MakeErrMsg(ErrMsg, "Couldn't fork");
266 // Child process: Execute the program.
268 // Redirect file descriptors...
271 if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
273 if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
274 if (redirects[1] && redirects[2] &&
275 *(redirects[1]) == *(redirects[2])) {
276 // If stdout and stderr should go to the same place, redirect stderr
277 // to the FD already open for stdout.
278 if (-1 == dup2(1,2)) {
279 MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
283 // Just redirect stderr
284 if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
289 if (memoryLimit!=0) {
290 SetMemoryLimits(memoryLimit);
294 std::string PathStr = Program;
296 execve(PathStr.c_str(),
297 const_cast<char **>(args),
298 const_cast<char **>(envp));
300 execv(PathStr.c_str(),
301 const_cast<char **>(args));
302 // If the execve() failed, we should exit. Follow Unix protocol and
303 // return 127 if the executable was not found, and 126 otherwise.
304 // Use _exit rather than exit so that atexit functions and static
305 // object destructors cloned from the parent process aren't
306 // redundantly run, and so that any data buffered in stdio buffers
307 // cloned from the parent aren't redundantly written out.
308 _exit(errno == ENOENT ? 127 : 126);
311 // Parent process: Break out of the switch to do our processing.
323 ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
324 bool WaitUntilTerminates, std::string *ErrMsg) {
325 #ifdef HAVE_SYS_WAIT_H
326 struct sigaction Act, Old;
327 assert(PI.Pid && "invalid pid to wait on, process not started?");
329 int WaitPidOptions = 0;
330 pid_t ChildPid = PI.Pid;
331 if (WaitUntilTerminates) {
333 } else if (SecondsToWait) {
334 // Install a timeout handler. The handler itself does nothing, but the
335 // simple fact of having a handler at all causes the wait below to return
336 // with EINTR, unlike if we used SIG_IGN.
337 memset(&Act, 0, sizeof(Act));
338 Act.sa_handler = TimeOutHandler;
339 sigemptyset(&Act.sa_mask);
340 sigaction(SIGALRM, &Act, &Old);
341 alarm(SecondsToWait);
342 } else if (SecondsToWait == 0)
343 WaitPidOptions = WNOHANG;
345 // Parent process: Wait for the child process to terminate.
347 ProcessInfo WaitResult;
350 WaitResult.Pid = waitpid(ChildPid, &status, WaitPidOptions);
351 } while (WaitUntilTerminates && WaitResult.Pid == -1 && errno == EINTR);
353 if (WaitResult.Pid != PI.Pid) {
354 if (WaitResult.Pid == 0) {
355 // Non-blocking wait.
358 if (SecondsToWait && errno == EINTR) {
360 kill(PI.Pid, SIGKILL);
362 // Turn off the alarm and restore the signal handler
364 sigaction(SIGALRM, &Old, nullptr);
366 // Wait for child to die
367 if (wait(&status) != ChildPid)
368 MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
370 MakeErrMsg(ErrMsg, "Child timed out", 0);
372 WaitResult.ReturnCode = -2; // Timeout detected
374 } else if (errno != EINTR) {
375 MakeErrMsg(ErrMsg, "Error waiting for child process");
376 WaitResult.ReturnCode = -1;
382 // We exited normally without timeout, so turn off the timer.
383 if (SecondsToWait && !WaitUntilTerminates) {
385 sigaction(SIGALRM, &Old, nullptr);
388 // Return the proper exit status. Detect error conditions
389 // so we can return -1 for them and set ErrMsg informatively.
391 if (WIFEXITED(status)) {
392 result = WEXITSTATUS(status);
393 WaitResult.ReturnCode = result;
397 *ErrMsg = llvm::sys::StrError(ENOENT);
398 WaitResult.ReturnCode = -1;
403 *ErrMsg = "Program could not be executed";
404 WaitResult.ReturnCode = -1;
407 } else if (WIFSIGNALED(status)) {
409 *ErrMsg = strsignal(WTERMSIG(status));
411 if (WCOREDUMP(status))
412 *ErrMsg += " (core dumped)";
415 // Return a special value to indicate that the process received an unhandled
416 // signal during execution as opposed to failing to execute.
417 WaitResult.ReturnCode = -2;
421 *ErrMsg = "Program::Wait is not implemented on this platform yet!";
422 ProcessInfo WaitResult;
423 WaitResult.ReturnCode = -2;
428 std::error_code sys::ChangeStdinToBinary(){
429 // Do nothing, as Unix doesn't differentiate between text and binary.
430 return std::error_code();
433 std::error_code sys::ChangeStdoutToBinary(){
434 // Do nothing, as Unix doesn't differentiate between text and binary.
435 return std::error_code();
439 llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
440 WindowsEncodingMethod Encoding /*unused*/) {
442 llvm::raw_fd_ostream OS(FileName, EC, llvm::sys::fs::OpenFlags::F_Text);
450 return std::make_error_code(std::errc::io_error);
455 bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
456 static long ArgMax = sysconf(_SC_ARG_MAX);
458 // System says no practical limit.
462 // Conservatively account for space required by environment variables.
463 long HalfArgMax = ArgMax / 2;
465 size_t ArgLength = 0;
466 for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
468 ArgLength += strlen(*I) + 1;
469 if (ArgLength > size_t(HalfArgMax)) {