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
54 ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
56 // This function just uses the PATH environment variable to find the program.
58 sys::FindProgramByName(const std::string& progName) {
60 // Check some degenerate cases
61 if (progName.length() == 0) // no program
63 std::string temp = progName;
64 // Use the given path verbatim if it contains any slashes; this matches
65 // the behavior of sh(1) and friends.
66 if (progName.find('/') != std::string::npos)
69 // At this point, the file name is valid and does not contain slashes. Search
70 // for it through the directories specified in the PATH environment variable.
72 // Get the path. If its empty, we can't do anything to find it.
73 const char *PathStr = getenv("PATH");
77 // Now we have a colon separated list of directories to search; try them.
78 size_t PathLen = strlen(PathStr);
80 // Find the first colon...
81 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
83 // Check to see if this first directory contains the executable...
84 SmallString<128> FilePath(PathStr,Colon);
85 sys::path::append(FilePath, progName);
86 if (sys::fs::can_execute(Twine(FilePath)))
87 return FilePath.str(); // Found the executable!
89 // Nope it wasn't in this directory, check the next path in the list!
90 PathLen -= Colon-PathStr;
93 // Advance past duplicate colons
94 while (*PathStr == ':') {
102 static bool RedirectIO(const StringRef *Path, int FD, std::string* ErrMsg) {
107 // Redirect empty paths to /dev/null
113 int InFD = open(File.c_str(), FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
115 MakeErrMsg(ErrMsg, "Cannot open file '" + File + "' for "
116 + (FD == 0 ? "input" : "output"));
120 // Install it as the requested FD
121 if (dup2(InFD, FD) == -1) {
122 MakeErrMsg(ErrMsg, "Cannot dup2");
126 close(InFD); // Close the original FD
130 #ifdef HAVE_POSIX_SPAWN
131 static bool RedirectIO_PS(const std::string *Path, int FD, std::string *ErrMsg,
132 posix_spawn_file_actions_t *FileActions) {
137 // Redirect empty paths to /dev/null
140 File = Path->c_str();
142 if (int Err = posix_spawn_file_actions_addopen(
143 FileActions, FD, File,
144 FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
145 return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
150 static void TimeOutHandler(int Sig) {
153 static void SetMemoryLimits (unsigned size)
155 #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
157 __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
160 getrlimit (RLIMIT_DATA, &r);
162 setrlimit (RLIMIT_DATA, &r);
164 // Resident set size.
165 getrlimit (RLIMIT_RSS, &r);
167 setrlimit (RLIMIT_RSS, &r);
169 #ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
170 // Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
171 // of virtual memory for shadow memory mapping.
172 #if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
174 getrlimit (RLIMIT_AS, &r);
176 setrlimit (RLIMIT_AS, &r);
184 static bool Execute(ProcessInfo &PI, StringRef Program, const char **args,
185 const char **envp, const StringRef **redirects,
186 unsigned memoryLimit, std::string *ErrMsg) {
187 if (!llvm::sys::fs::exists(Program)) {
189 *ErrMsg = std::string("Executable \"") + Program.str() +
190 std::string("\" doesn't exist!");
194 // If this OS has posix_spawn and there is no memory limit being implied, use
195 // posix_spawn. It is more efficient than fork/exec.
196 #ifdef HAVE_POSIX_SPAWN
197 if (memoryLimit == 0) {
198 posix_spawn_file_actions_t FileActionsStore;
199 posix_spawn_file_actions_t *FileActions = nullptr;
201 // If we call posix_spawn_file_actions_addopen we have to make sure the
202 // c strings we pass to it stay alive until the call to posix_spawn,
203 // so we copy any StringRefs into this variable.
204 std::string RedirectsStorage[3];
207 std::string *RedirectsStr[3] = {nullptr, nullptr, nullptr};
208 for (int I = 0; I < 3; ++I) {
210 RedirectsStorage[I] = *redirects[I];
211 RedirectsStr[I] = &RedirectsStorage[I];
215 FileActions = &FileActionsStore;
216 posix_spawn_file_actions_init(FileActions);
218 // Redirect stdin/stdout.
219 if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
220 RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
222 if (redirects[1] == nullptr || redirects[2] == nullptr ||
223 *redirects[1] != *redirects[2]) {
224 // Just redirect stderr
225 if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
228 // If stdout and stderr should go to the same place, redirect stderr
229 // to the FD already open for stdout.
230 if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
231 return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
236 #if !defined(__APPLE__)
237 envp = const_cast<const char **>(environ);
239 // environ is missing in dylibs.
240 envp = const_cast<const char **>(*_NSGetEnviron());
243 // Explicitly initialized to prevent what appears to be a valgrind false
246 int Err = posix_spawn(&PID, Program.str().c_str(), FileActions,
247 /*attrp*/nullptr, const_cast<char **>(args),
248 const_cast<char **>(envp));
251 posix_spawn_file_actions_destroy(FileActions);
254 return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
262 // Create a child process.
265 // An error occurred: Return to the caller.
267 MakeErrMsg(ErrMsg, "Couldn't fork");
270 // Child process: Execute the program.
272 // Redirect file descriptors...
275 if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
277 if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
278 if (redirects[1] && redirects[2] &&
279 *(redirects[1]) == *(redirects[2])) {
280 // If stdout and stderr should go to the same place, redirect stderr
281 // to the FD already open for stdout.
282 if (-1 == dup2(1,2)) {
283 MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
287 // Just redirect stderr
288 if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
293 if (memoryLimit!=0) {
294 SetMemoryLimits(memoryLimit);
298 std::string PathStr = Program;
300 execve(PathStr.c_str(),
301 const_cast<char **>(args),
302 const_cast<char **>(envp));
304 execv(PathStr.c_str(),
305 const_cast<char **>(args));
306 // If the execve() failed, we should exit. Follow Unix protocol and
307 // return 127 if the executable was not found, and 126 otherwise.
308 // Use _exit rather than exit so that atexit functions and static
309 // object destructors cloned from the parent process aren't
310 // redundantly run, and so that any data buffered in stdio buffers
311 // cloned from the parent aren't redundantly written out.
312 _exit(errno == ENOENT ? 127 : 126);
315 // Parent process: Break out of the switch to do our processing.
327 ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
328 bool WaitUntilTerminates, std::string *ErrMsg) {
329 #ifdef HAVE_SYS_WAIT_H
330 struct sigaction Act, Old;
331 assert(PI.Pid && "invalid pid to wait on, process not started?");
333 int WaitPidOptions = 0;
334 pid_t ChildPid = PI.Pid;
335 if (WaitUntilTerminates) {
337 ChildPid = -1; // mimic a wait() using waitpid()
338 } else if (SecondsToWait) {
339 // Install a timeout handler. The handler itself does nothing, but the
340 // simple fact of having a handler at all causes the wait below to return
341 // with EINTR, unlike if we used SIG_IGN.
342 memset(&Act, 0, sizeof(Act));
343 Act.sa_handler = TimeOutHandler;
344 sigemptyset(&Act.sa_mask);
345 sigaction(SIGALRM, &Act, &Old);
346 alarm(SecondsToWait);
347 } else if (SecondsToWait == 0)
348 WaitPidOptions = WNOHANG;
350 // Parent process: Wait for the child process to terminate.
352 ProcessInfo WaitResult;
355 WaitResult.Pid = waitpid(ChildPid, &status, WaitPidOptions);
356 } while (WaitUntilTerminates && WaitResult.Pid == -1 && errno == EINTR);
358 if (WaitResult.Pid != PI.Pid) {
359 if (WaitResult.Pid == 0) {
360 // Non-blocking wait.
363 if (SecondsToWait && errno == EINTR) {
365 kill(PI.Pid, SIGKILL);
367 // Turn off the alarm and restore the signal handler
369 sigaction(SIGALRM, &Old, nullptr);
371 // Wait for child to die
372 if (wait(&status) != ChildPid)
373 MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
375 MakeErrMsg(ErrMsg, "Child timed out", 0);
377 WaitResult.ReturnCode = -2; // Timeout detected
379 } else if (errno != EINTR) {
380 MakeErrMsg(ErrMsg, "Error waiting for child process");
381 WaitResult.ReturnCode = -1;
387 // We exited normally without timeout, so turn off the timer.
388 if (SecondsToWait && !WaitUntilTerminates) {
390 sigaction(SIGALRM, &Old, nullptr);
393 // Return the proper exit status. Detect error conditions
394 // so we can return -1 for them and set ErrMsg informatively.
396 if (WIFEXITED(status)) {
397 result = WEXITSTATUS(status);
398 WaitResult.ReturnCode = result;
402 *ErrMsg = llvm::sys::StrError(ENOENT);
403 WaitResult.ReturnCode = -1;
408 *ErrMsg = "Program could not be executed";
409 WaitResult.ReturnCode = -1;
412 } else if (WIFSIGNALED(status)) {
414 *ErrMsg = strsignal(WTERMSIG(status));
416 if (WCOREDUMP(status))
417 *ErrMsg += " (core dumped)";
420 // Return a special value to indicate that the process received an unhandled
421 // signal during execution as opposed to failing to execute.
422 WaitResult.ReturnCode = -2;
426 *ErrMsg = "Program::Wait is not implemented on this platform yet!";
427 ProcessInfo WaitResult;
428 WaitResult.ReturnCode = -2;
433 std::error_code sys::ChangeStdinToBinary(){
434 // Do nothing, as Unix doesn't differentiate between text and binary.
435 return std::error_code();
438 std::error_code sys::ChangeStdoutToBinary(){
439 // Do nothing, as Unix doesn't differentiate between text and binary.
440 return std::error_code();
443 bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
444 static long ArgMax = sysconf(_SC_ARG_MAX);
446 // System says no practical limit.
450 // Conservatively account for space required by environment variables.
451 long HalfArgMax = ArgMax / 2;
453 size_t ArgLength = 0;
454 for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
456 ArgLength += strlen(*I) + 1;
457 if (ArgLength > size_t(HalfArgMax)) {