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/Support/Compiler.h"
21 #include "llvm/Support/FileSystem.h"
22 #include <llvm/Config/config.h>
26 #if HAVE_SYS_RESOURCE_H
27 #include <sys/resource.h>
38 #ifdef HAVE_POSIX_SPAWN
40 #define _RESTRICT_KYWD
43 #if !defined(__APPLE__)
44 extern char **environ;
46 #include <crt_externs.h> // _NSGetEnviron
53 ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
55 // This function just uses the PATH environment variable to find the program.
57 sys::FindProgramByName(const std::string& progName) {
59 // Check some degenerate cases
60 if (progName.length() == 0) // no program
62 std::string temp = progName;
63 // Use the given path verbatim if it contains any slashes; this matches
64 // the behavior of sh(1) and friends.
65 if (progName.find('/') != std::string::npos)
68 // At this point, the file name is valid and does not contain slashes. Search
69 // for it through the directories specified in the PATH environment variable.
71 // Get the path. If its empty, we can't do anything to find it.
72 const char *PathStr = getenv("PATH");
76 // Now we have a colon separated list of directories to search; try them.
77 size_t PathLen = strlen(PathStr);
79 // Find the first colon...
80 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
82 // Check to see if this first directory contains the executable...
83 SmallString<128> FilePath(PathStr,Colon);
84 sys::path::append(FilePath, progName);
85 if (sys::fs::can_execute(Twine(FilePath)))
86 return FilePath.str(); // Found the executable!
88 // Nope it wasn't in this directory, check the next path in the list!
89 PathLen -= Colon-PathStr;
92 // Advance past duplicate colons
93 while (*PathStr == ':') {
101 static bool RedirectIO(const StringRef *Path, int FD, std::string* ErrMsg) {
106 // Redirect empty paths to /dev/null
112 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
114 MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
115 + (FD == 0 ? "input" : "output"));
119 // Install it as the requested FD
120 if (dup2(InFD, FD) == -1) {
121 MakeErrMsg(ErrMsg, "Cannot dup2");
125 close(InFD); // Close the original FD
129 #ifdef HAVE_POSIX_SPAWN
130 static bool RedirectIO_PS(const std::string *Path, int FD, std::string *ErrMsg,
131 posix_spawn_file_actions_t *FileActions) {
136 // Redirect empty paths to /dev/null
139 File = Path->c_str();
141 if (int Err = posix_spawn_file_actions_addopen(
142 FileActions, FD, File,
143 FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
144 return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
149 static void TimeOutHandler(int Sig) {
152 static void SetMemoryLimits (unsigned size)
154 #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
156 __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
159 getrlimit (RLIMIT_DATA, &r);
161 setrlimit (RLIMIT_DATA, &r);
163 // Resident set size.
164 getrlimit (RLIMIT_RSS, &r);
166 setrlimit (RLIMIT_RSS, &r);
168 #ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
169 // Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
170 // of virtual memory for shadow memory mapping.
171 #if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
173 getrlimit (RLIMIT_AS, &r);
175 setrlimit (RLIMIT_AS, &r);
183 static bool Execute(ProcessInfo &PI, StringRef Program, const char **args,
184 const char **envp, const StringRef **redirects,
185 unsigned memoryLimit, std::string *ErrMsg) {
186 if (!llvm::sys::fs::exists(Program)) {
188 *ErrMsg = std::string("Executable \"") + Program.str() +
189 std::string("\" doesn't exist!");
193 // If this OS has posix_spawn and there is no memory limit being implied, use
194 // posix_spawn. It is more efficient than fork/exec.
195 #ifdef HAVE_POSIX_SPAWN
196 if (memoryLimit == 0) {
197 posix_spawn_file_actions_t FileActionsStore;
198 posix_spawn_file_actions_t *FileActions = nullptr;
200 // If we call posix_spawn_file_actions_addopen we have to make sure the
201 // c strings we pass to it stay alive until the call to posix_spawn,
202 // so we copy any StringRefs into this variable.
203 std::string RedirectsStorage[3];
206 std::string *RedirectsStr[3] = {nullptr, nullptr, nullptr};
207 for (int I = 0; I < 3; ++I) {
209 RedirectsStorage[I] = *redirects[I];
210 RedirectsStr[I] = &RedirectsStorage[I];
214 FileActions = &FileActionsStore;
215 posix_spawn_file_actions_init(FileActions);
217 // Redirect stdin/stdout.
218 if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
219 RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
221 if (redirects[1] == nullptr || redirects[2] == nullptr ||
222 *redirects[1] != *redirects[2]) {
223 // Just redirect stderr
224 if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
227 // If stdout and stderr should go to the same place, redirect stderr
228 // to the FD already open for stdout.
229 if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
230 return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
235 #if !defined(__APPLE__)
236 envp = const_cast<const char **>(environ);
238 // environ is missing in dylibs.
239 envp = const_cast<const char **>(*_NSGetEnviron());
242 // Explicitly initialized to prevent what appears to be a valgrind false
245 int Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
246 /*attrp*/nullptr, const_cast<char **>(args),
247 const_cast<char **>(envp));
250 posix_spawn_file_actions_destroy(FileActions);
253 return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
261 // Create a child process.
264 // An error occurred: Return to the caller.
266 MakeErrMsg(ErrMsg, "Couldn't fork");
269 // Child process: Execute the program.
271 // Redirect file descriptors...
274 if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
276 if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
277 if (redirects[1] && redirects[2] &&
278 *(redirects[1]) == *(redirects[2])) {
279 // If stdout and stderr should go to the same place, redirect stderr
280 // to the FD already open for stdout.
281 if (-1 == dup2(1,2)) {
282 MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
286 // Just redirect stderr
287 if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
292 if (memoryLimit!=0) {
293 SetMemoryLimits(memoryLimit);
297 std::string PathStr = Program;
299 execve(PathStr.c_str(),
300 const_cast<char **>(args),
301 const_cast<char **>(envp));
303 execv(PathStr.c_str(),
304 const_cast<char **>(args));
305 // If the execve() failed, we should exit. Follow Unix protocol and
306 // return 127 if the executable was not found, and 126 otherwise.
307 // Use _exit rather than exit so that atexit functions and static
308 // object destructors cloned from the parent process aren't
309 // redundantly run, and so that any data buffered in stdio buffers
310 // cloned from the parent aren't redundantly written out.
311 _exit(errno == ENOENT ? 127 : 126);
314 // Parent process: Break out of the switch to do our processing.
326 ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
327 bool WaitUntilTerminates, std::string *ErrMsg) {
328 #ifdef HAVE_SYS_WAIT_H
329 struct sigaction Act, Old;
330 assert(PI.Pid && "invalid pid to wait on, process not started?");
332 int WaitPidOptions = 0;
333 pid_t ChildPid = PI.Pid;
334 if (WaitUntilTerminates) {
336 ChildPid = -1; // mimic a wait() using waitpid()
337 } else if (SecondsToWait) {
338 // Install a timeout handler. The handler itself does nothing, but the
339 // simple fact of having a handler at all causes the wait below to return
340 // with EINTR, unlike if we used SIG_IGN.
341 memset(&Act, 0, sizeof(Act));
342 Act.sa_handler = TimeOutHandler;
343 sigemptyset(&Act.sa_mask);
344 sigaction(SIGALRM, &Act, &Old);
345 alarm(SecondsToWait);
346 } else if (SecondsToWait == 0)
347 WaitPidOptions = WNOHANG;
349 // Parent process: Wait for the child process to terminate.
351 ProcessInfo WaitResult;
352 WaitResult.Pid = waitpid(ChildPid, &status, WaitPidOptions);
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 error_code sys::ChangeStdinToBinary(){
429 // Do nothing, as Unix doesn't differentiate between text and binary.
430 return make_error_code(errc::success);
433 error_code sys::ChangeStdoutToBinary(){
434 // Do nothing, as Unix doesn't differentiate between text and binary.
435 return make_error_code(errc::success);
438 bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
439 static long ArgMax = sysconf(_SC_ARG_MAX);
441 // System says no practical limit.
445 // Conservatively account for space required by environment variables.
448 size_t ArgLength = 0;
449 for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
451 ArgLength += strlen(*I) + 1;
452 if (ArgLength > size_t(ArgMax)) {