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 #if !defined(__APPLE__)
41 extern char **environ;
43 #include <crt_externs.h> // _NSGetEnviron
50 // This function just uses the PATH environment variable to find the program.
52 sys::FindProgramByName(const std::string& progName) {
54 // Check some degenerate cases
55 if (progName.length() == 0) // no program
58 if (!temp.set(progName)) // invalid name
60 // Use the given path verbatim if it contains any slashes; this matches
61 // the behavior of sh(1) and friends.
62 if (progName.find('/') != std::string::npos)
65 // At this point, the file name is valid and does not contain slashes. Search
66 // for it through the directories specified in the PATH environment variable.
68 // Get the path. If its empty, we can't do anything to find it.
69 const char *PathStr = getenv("PATH");
73 // Now we have a colon separated list of directories to search; try them.
74 size_t PathLen = strlen(PathStr);
76 // Find the first colon...
77 const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
79 // Check to see if this first directory contains the executable...
81 if (FilePath.set(std::string(PathStr,Colon))) {
82 FilePath.appendComponent(progName);
83 if (FilePath.canExecute())
84 return FilePath.str(); // Found the executable!
87 // Nope it wasn't in this directory, check the next path in the list!
88 PathLen -= Colon-PathStr;
91 // Advance past duplicate colons
92 while (*PathStr == ':') {
100 static bool RedirectIO(const Path *Path, int FD, std::string* ErrMsg) {
101 if (Path == 0) // Noop
105 // Redirect empty paths to /dev/null
108 File = Path->c_str();
111 int InFD = open(File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666);
113 MakeErrMsg(ErrMsg, "Cannot open file '" + std::string(File) + "' for "
114 + (FD == 0 ? "input" : "output"));
118 // Install it as the requested FD
119 if (dup2(InFD, FD) == -1) {
120 MakeErrMsg(ErrMsg, "Cannot dup2");
124 close(InFD); // Close the original FD
128 #ifdef HAVE_POSIX_SPAWN
129 static bool RedirectIO_PS(const Path *Path, int FD, std::string *ErrMsg,
130 posix_spawn_file_actions_t *FileActions) {
131 if (Path == 0) // Noop
135 // Redirect empty paths to /dev/null
138 File = Path->c_str();
140 if (int Err = posix_spawn_file_actions_addopen(FileActions, FD,
141 File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666))
142 return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
147 static void TimeOutHandler(int Sig) {
150 static void SetMemoryLimits (unsigned size)
152 #if HAVE_SYS_RESOURCE_H && HAVE_GETRLIMIT && HAVE_SETRLIMIT
154 __typeof__ (r.rlim_cur) limit = (__typeof__ (r.rlim_cur)) (size) * 1048576;
157 getrlimit (RLIMIT_DATA, &r);
159 setrlimit (RLIMIT_DATA, &r);
161 // Resident set size.
162 getrlimit (RLIMIT_RSS, &r);
164 setrlimit (RLIMIT_RSS, &r);
166 #ifdef RLIMIT_AS // e.g. NetBSD doesn't have it.
167 // Don't set virtual memory limit if built with any Sanitizer. They need 80Tb
168 // of virtual memory for shadow memory mapping.
169 #if !LLVM_MEMORY_SANITIZER_BUILD && !LLVM_ADDRESS_SANITIZER_BUILD
171 getrlimit (RLIMIT_AS, &r);
173 setrlimit (RLIMIT_AS, &r);
181 static bool Execute(void **Data, const Path &path, const char **args,
182 const char **envp, const Path **redirects,
183 unsigned memoryLimit, std::string *ErrMsg) {
184 // If this OS has posix_spawn and there is no memory limit being implied, use
185 // posix_spawn. It is more efficient than fork/exec.
186 #ifdef HAVE_POSIX_SPAWN
187 if (memoryLimit == 0) {
188 posix_spawn_file_actions_t FileActionsStore;
189 posix_spawn_file_actions_t *FileActions = 0;
192 FileActions = &FileActionsStore;
193 posix_spawn_file_actions_init(FileActions);
195 // Redirect stdin/stdout.
196 if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) ||
197 RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions))
199 if (redirects[1] == 0 || redirects[2] == 0 ||
200 *redirects[1] != *redirects[2]) {
201 // Just redirect stderr
202 if (RedirectIO_PS(redirects[2], 2, ErrMsg, FileActions)) return false;
204 // If stdout and stderr should go to the same place, redirect stderr
205 // to the FD already open for stdout.
206 if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2))
207 return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err);
212 #if !defined(__APPLE__)
213 envp = const_cast<const char **>(environ);
215 // environ is missing in dylibs.
216 envp = const_cast<const char **>(*_NSGetEnviron());
219 // Explicitly initialized to prevent what appears to be a valgrind false
222 int Err = posix_spawn(&PID, path.c_str(), FileActions, /*attrp*/0,
223 const_cast<char **>(args), const_cast<char **>(envp));
226 posix_spawn_file_actions_destroy(FileActions);
229 return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err);
232 *Data = reinterpret_cast<void*>(PID);
237 // Create a child process.
240 // An error occurred: Return to the caller.
242 MakeErrMsg(ErrMsg, "Couldn't fork");
245 // Child process: Execute the program.
247 // Redirect file descriptors...
250 if (RedirectIO(redirects[0], 0, ErrMsg)) { return false; }
252 if (RedirectIO(redirects[1], 1, ErrMsg)) { return false; }
253 if (redirects[1] && redirects[2] &&
254 *(redirects[1]) == *(redirects[2])) {
255 // If stdout and stderr should go to the same place, redirect stderr
256 // to the FD already open for stdout.
257 if (-1 == dup2(1,2)) {
258 MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
262 // Just redirect stderr
263 if (RedirectIO(redirects[2], 2, ErrMsg)) { return false; }
268 if (memoryLimit!=0) {
269 SetMemoryLimits(memoryLimit);
275 const_cast<char **>(args),
276 const_cast<char **>(envp));
279 const_cast<char **>(args));
280 // If the execve() failed, we should exit. Follow Unix protocol and
281 // return 127 if the executable was not found, and 126 otherwise.
282 // Use _exit rather than exit so that atexit functions and static
283 // object destructors cloned from the parent process aren't
284 // redundantly run, and so that any data buffered in stdio buffers
285 // cloned from the parent aren't redundantly written out.
286 _exit(errno == ENOENT ? 127 : 126);
289 // Parent process: Break out of the switch to do our processing.
295 *Data = reinterpret_cast<void*>(child);
300 static int Wait(void *&Data, const sys::Path &path, unsigned secondsToWait,
301 std::string *ErrMsg) {
302 #ifdef HAVE_SYS_WAIT_H
303 struct sigaction Act, Old;
304 assert(Data && "invalid pid to wait on, process not started?");
306 // Install a timeout handler. The handler itself does nothing, but the simple
307 // fact of having a handler at all causes the wait below to return with EINTR,
308 // unlike if we used SIG_IGN.
310 memset(&Act, 0, sizeof(Act));
311 Act.sa_handler = TimeOutHandler;
312 sigemptyset(&Act.sa_mask);
313 sigaction(SIGALRM, &Act, &Old);
314 alarm(secondsToWait);
317 // Parent process: Wait for the child process to terminate.
319 uint64_t pid = reinterpret_cast<uint64_t>(Data);
320 pid_t child = static_cast<pid_t>(pid);
321 while (waitpid(pid, &status, 0) != child)
322 if (secondsToWait && errno == EINTR) {
324 kill(child, SIGKILL);
326 // Turn off the alarm and restore the signal handler
328 sigaction(SIGALRM, &Old, 0);
330 // Wait for child to die
331 if (wait(&status) != child)
332 MakeErrMsg(ErrMsg, "Child timed out but wouldn't die");
334 MakeErrMsg(ErrMsg, "Child timed out", 0);
336 return -2; // Timeout detected
337 } else if (errno != EINTR) {
338 MakeErrMsg(ErrMsg, "Error waiting for child process");
342 // We exited normally without timeout, so turn off the timer.
345 sigaction(SIGALRM, &Old, 0);
348 // Return the proper exit status. Detect error conditions
349 // so we can return -1 for them and set ErrMsg informatively.
351 if (WIFEXITED(status)) {
352 result = WEXITSTATUS(status);
353 #ifdef HAVE_POSIX_SPAWN
354 // The posix_spawn child process returns 127 on any kind of error.
355 // Following the POSIX convention for command-line tools (which posix_spawn
356 // itself apparently does not), check to see if the failure was due to some
357 // reason other than the file not existing, and return 126 in this case.
359 if (result == 127 && !llvm::sys::fs::exists(path.str(), Exists) && Exists)
364 *ErrMsg = llvm::sys::StrError(ENOENT);
369 *ErrMsg = "Program could not be executed";
372 } else if (WIFSIGNALED(status)) {
374 *ErrMsg = strsignal(WTERMSIG(status));
376 if (WCOREDUMP(status))
377 *ErrMsg += " (core dumped)";
380 // Return a special value to indicate that the process received an unhandled
381 // signal during execution as opposed to failing to execute.
387 *ErrMsg = "Program::Wait is not implemented on this platform yet!";
394 error_code sys::ChangeStdinToBinary(){
395 // Do nothing, as Unix doesn't differentiate between text and binary.
396 return make_error_code(errc::success);
399 error_code sys::ChangeStdoutToBinary(){
400 // Do nothing, as Unix doesn't differentiate between text and binary.
401 return make_error_code(errc::success);
404 error_code sys::ChangeStderrToBinary(){
405 // Do nothing, as Unix doesn't differentiate between text and binary.
406 return make_error_code(errc::success);
409 bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
410 static long ArgMax = sysconf(_SC_ARG_MAX);
412 // System says no practical limit.
416 // Conservatively account for space required by environment variables.
419 size_t ArgLength = 0;
420 for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
422 ArgLength += strlen(*I) + 1;
423 if (ArgLength > size_t(ArgMax)) {