1 // Copyright 2009 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 #include <sys/types.h>
49 // If the buffer ends in the middle of a UTF-8 sequence then we return
50 // the length of the string up to but not including the incomplete UTF-8
51 // sequence. If the buffer ends with a valid UTF-8 sequence then we
52 // return the whole buffer.
53 static int LengthWithoutIncompleteUtf8(char* buffer, int len) {
56 static const int kUtf8SingleByteMask = 0x80;
57 static const int kUtf8SingleByteValue = 0x00;
59 static const int kUtf8TwoByteMask = 0xe0;
60 static const int kUtf8TwoByteValue = 0xc0;
62 static const int kUtf8ThreeByteMask = 0xf0;
63 static const int kUtf8ThreeByteValue = 0xe0;
65 static const int kUtf8FourByteMask = 0xf8;
66 static const int kUtf8FourByteValue = 0xf0;
67 // Subsequent bytes of a multi-byte encoding.
68 static const int kMultiByteMask = 0xc0;
69 static const int kMultiByteValue = 0x80;
70 int multi_byte_bytes_seen = 0;
72 int c = buffer[answer - 1];
73 // Ends in valid single-byte sequence?
74 if ((c & kUtf8SingleByteMask) == kUtf8SingleByteValue) return answer;
75 // Ends in one or more subsequent bytes of a multi-byte value?
76 if ((c & kMultiByteMask) == kMultiByteValue) {
77 multi_byte_bytes_seen++;
80 if ((c & kUtf8TwoByteMask) == kUtf8TwoByteValue) {
81 if (multi_byte_bytes_seen >= 1) {
85 } else if ((c & kUtf8ThreeByteMask) == kUtf8ThreeByteValue) {
86 if (multi_byte_bytes_seen >= 2) {
90 } else if ((c & kUtf8FourByteMask) == kUtf8FourByteValue) {
91 if (multi_byte_bytes_seen >= 3) {
96 return answer; // Malformed UTF-8.
104 // Suspends the thread until there is data available from the child process.
105 // Returns false on timeout, true on data ready.
106 static bool WaitOnFD(int fd,
109 struct timeval& start_time) {
110 fd_set readfds, writefds, exceptfds;
111 struct timeval timeout;
113 if (total_timeout != -1) {
114 struct timeval time_now;
115 gettimeofday(&time_now, NULL);
116 int seconds = time_now.tv_sec - start_time.tv_sec;
117 gone = seconds * 1000 + (time_now.tv_usec - start_time.tv_usec) / 1000;
118 if (gone >= total_timeout) return false;
123 FD_SET(fd, &readfds);
124 FD_SET(fd, &exceptfds);
125 if (read_timeout == -1 ||
126 (total_timeout != -1 && total_timeout - gone < read_timeout)) {
127 read_timeout = total_timeout - gone;
129 timeout.tv_usec = (read_timeout % 1000) * 1000;
130 timeout.tv_sec = read_timeout / 1000;
131 int number_of_fds_ready = select(fd + 1,
135 read_timeout != -1 ? &timeout : NULL);
136 return number_of_fds_ready == 1;
140 // Checks whether we ran out of time on the timeout. Returns true if we ran out
141 // of time, false if we still have time.
142 static bool TimeIsOut(const struct timeval& start_time, const int& total_time) {
143 if (total_time == -1) return false;
144 struct timeval time_now;
145 gettimeofday(&time_now, NULL);
146 // Careful about overflow.
147 int seconds = time_now.tv_sec - start_time.tv_sec;
149 if (seconds * 1000 > total_time) return true;
152 int useconds = time_now.tv_usec - start_time.tv_usec;
153 if (seconds * 1000000 + useconds > total_time * 1000) {
160 // A utility class that does a non-hanging waitpid on the child process if we
161 // bail out of the System() function early. If you don't ever do a waitpid on
162 // a subprocess then it turns into one of those annoying 'zombie processes'.
163 class ZombieProtector {
165 explicit ZombieProtector(int pid): pid_(pid) { }
166 ~ZombieProtector() { if (pid_ != 0) waitpid(pid_, NULL, 0); }
167 void ChildIsDeadNow() { pid_ = 0; }
173 // A utility class that closes a file descriptor when it goes out of scope.
176 explicit OpenFDCloser(int fd): fd_(fd) { }
177 ~OpenFDCloser() { close(fd_); }
183 // A utility class that takes the array of command arguments and puts then in an
184 // array of new[]ed UTF-8 C strings. Deallocates them again when it goes out of
189 exec_args_[0] = NULL;
191 bool Init(Handle<Value> arg0, Handle<Array> command_args) {
192 String::Utf8Value prog(arg0);
194 const char* message =
195 "os.system(): String conversion of program name failed";
196 ThrowException(String::New(message));
199 int len = prog.length() + 3;
200 char* c_arg = new char[len];
201 snprintf(c_arg, len, "%s", *prog);
202 exec_args_[0] = c_arg;
204 for (unsigned j = 0; j < command_args->Length(); i++, j++) {
205 Handle<Value> arg(command_args->Get(Integer::New(j)));
206 String::Utf8Value utf8_arg(arg);
207 if (*utf8_arg == NULL) {
208 exec_args_[i] = NULL; // Consistent state for destructor.
209 const char* message =
210 "os.system(): String conversion of argument failed.";
211 ThrowException(String::New(message));
214 int len = utf8_arg.length() + 1;
215 char* c_arg = new char[len];
216 snprintf(c_arg, len, "%s", *utf8_arg);
217 exec_args_[i] = c_arg;
219 exec_args_[i] = NULL;
223 for (unsigned i = 0; i < kMaxArgs; i++) {
224 if (exec_args_[i] == NULL) {
227 delete [] exec_args_[i];
231 static const unsigned kMaxArgs = 1000;
232 char** arg_array() { return exec_args_; }
233 char* arg0() { return exec_args_[0]; }
236 char* exec_args_[kMaxArgs + 1];
240 // Gets the optional timeouts from the arguments to the system() call.
241 static bool GetTimeouts(const Arguments& args,
243 int* total_timeout) {
244 if (args.Length() > 3) {
245 if (args[3]->IsNumber()) {
246 *total_timeout = args[3]->Int32Value();
248 ThrowException(String::New("system: Argument 4 must be a number"));
252 if (args.Length() > 2) {
253 if (args[2]->IsNumber()) {
254 *read_timeout = args[2]->Int32Value();
256 ThrowException(String::New("system: Argument 3 must be a number"));
264 static const int kReadFD = 0;
265 static const int kWriteFD = 1;
268 // This is run in the child process after fork() but before exec(). It normally
269 // ends with the child process being replaced with the desired child program.
270 // It only returns if an error occurred.
271 static void ExecSubprocess(int* exec_error_fds,
273 ExecArgs& exec_args) {
274 close(exec_error_fds[kReadFD]); // Don't need this in the child.
275 close(stdout_fds[kReadFD]); // Don't need this in the child.
276 close(1); // Close stdout.
277 dup2(stdout_fds[kWriteFD], 1); // Dup pipe fd to stdout.
278 close(stdout_fds[kWriteFD]); // Don't need the original fd now.
279 fcntl(exec_error_fds[kWriteFD], F_SETFD, FD_CLOEXEC);
280 execvp(exec_args.arg0(), exec_args.arg_array());
281 // Only get here if the exec failed. Write errno to the parent to tell
282 // them it went wrong. If it went well the pipe is closed.
286 bytes_written = write(exec_error_fds[kWriteFD], &err, sizeof(err));
287 } while (bytes_written == -1 && errno == EINTR);
288 // Return (and exit child process).
292 // Runs in the parent process. Checks that the child was able to exec (closing
293 // the file desriptor), or reports an error if it failed.
294 static bool ChildLaunchedOK(int* exec_error_fds) {
298 bytes_read = read(exec_error_fds[kReadFD], &err, sizeof(err));
299 } while (bytes_read == -1 && errno == EINTR);
300 if (bytes_read != 0) {
301 ThrowException(String::New(strerror(err)));
308 // Accumulates the output from the child in a string handle. Returns true if it
309 // succeeded or false if an exception was thrown.
310 static Handle<Value> GetStdout(int child_fd,
311 struct timeval& start_time,
314 Handle<String> accumulator = String::Empty();
317 static const int kStdoutReadBufferSize = 4096;
318 char buffer[kStdoutReadBufferSize];
320 if (fcntl(child_fd, F_SETFL, O_NONBLOCK) != 0) {
321 return ThrowException(String::New(strerror(errno)));
326 bytes_read = read(child_fd,
328 kStdoutReadBufferSize - fullness);
329 if (bytes_read == -1) {
330 if (errno == EAGAIN) {
331 if (!WaitOnFD(child_fd,
335 (TimeIsOut(start_time, total_timeout))) {
336 return ThrowException(String::New("Timed out waiting for output"));
339 } else if (errno == EINTR) {
345 if (bytes_read + fullness > 0) {
346 int length = bytes_read == 0 ?
347 bytes_read + fullness :
348 LengthWithoutIncompleteUtf8(buffer, bytes_read + fullness);
349 Handle<String> addition = String::New(buffer, length);
350 accumulator = String::Concat(accumulator, addition);
351 fullness = bytes_read + fullness - length;
352 memcpy(buffer, buffer + length, fullness);
354 } while (bytes_read != 0);
359 // Modern Linux has the waitid call, which is like waitpid, but more useful
360 // if you want a timeout. If we don't have waitid we can't limit the time
361 // waiting for the process to exit without losing the information about
362 // whether it exited normally. In the common case this doesn't matter because
363 // we don't get here before the child has closed stdout and most programs don't
364 // do that before they exit.
366 // We're disabling usage of waitid in Mac OS X because it doens't work for us:
367 // a parent process hangs on waiting while a child process is already a zombie.
368 // See http://code.google.com/p/v8/issues/detail?id=401.
369 #if defined(WNOWAIT) && !defined(ANDROID) && !defined(__APPLE__) \
370 && !defined(__NetBSD__)
371 #if !defined(__FreeBSD__)
377 // Get exit status of child.
378 static bool WaitForChild(int pid,
379 ZombieProtector& child_waiter,
380 struct timeval& start_time,
385 siginfo_t child_info;
386 child_info.si_pid = 0;
388 // Wait for child to exit.
389 while (child_info.si_pid == 0) {
390 waitid(P_PID, pid, &child_info, WEXITED | WNOHANG | WNOWAIT);
392 if (useconds < 1000000) useconds <<= 1;
393 if ((read_timeout != -1 && useconds / 1000 > read_timeout) ||
394 (TimeIsOut(start_time, total_timeout))) {
395 ThrowException(String::New("Timed out waiting for process to terminate"));
400 if (child_info.si_code == CLD_KILLED) {
404 "Child killed by signal %d",
405 child_info.si_status);
406 ThrowException(String::New(message));
409 if (child_info.si_code == CLD_EXITED && child_info.si_status != 0) {
413 "Child exited with status %d",
414 child_info.si_status);
415 ThrowException(String::New(message));
419 #else // No waitid call.
422 waitpid(pid, &child_status, 0); // We hang here if the child doesn't exit.
423 child_waiter.ChildIsDeadNow();
424 if (WIFSIGNALED(child_status)) {
428 "Child killed by signal %d",
429 WTERMSIG(child_status));
430 ThrowException(String::New(message));
433 if (WEXITSTATUS(child_status) != 0) {
435 int exit_status = WEXITSTATUS(child_status);
438 "Child exited with status %d",
440 ThrowException(String::New(message));
444 #endif // No waitid call.
450 // Implementation of the system() function (see d8.h for details).
451 Handle<Value> Shell::System(const Arguments& args) {
453 int read_timeout = -1;
454 int total_timeout = -1;
455 if (!GetTimeouts(args, &read_timeout, &total_timeout)) return v8::Undefined();
456 Handle<Array> command_args;
457 if (args.Length() > 1) {
458 if (!args[1]->IsArray()) {
459 return ThrowException(String::New("system: Argument 2 must be an array"));
461 command_args = Handle<Array>::Cast(args[1]);
463 command_args = Array::New(0);
465 if (command_args->Length() > ExecArgs::kMaxArgs) {
466 return ThrowException(String::New("Too many arguments to system()"));
468 if (args.Length() < 1) {
469 return ThrowException(String::New("Too few arguments to system()"));
472 struct timeval start_time;
473 gettimeofday(&start_time, NULL);
476 if (!exec_args.Init(args[0], command_args)) {
477 return v8::Undefined();
479 int exec_error_fds[2];
482 if (pipe(exec_error_fds) != 0) {
483 return ThrowException(String::New("pipe syscall failed."));
485 if (pipe(stdout_fds) != 0) {
486 return ThrowException(String::New("pipe syscall failed."));
490 if (pid == 0) { // Child process.
491 ExecSubprocess(exec_error_fds, stdout_fds, exec_args);
495 // Parent process. Ensure that we clean up if we exit this function early.
496 ZombieProtector child_waiter(pid);
497 close(exec_error_fds[kWriteFD]);
498 close(stdout_fds[kWriteFD]);
499 OpenFDCloser error_read_closer(exec_error_fds[kReadFD]);
500 OpenFDCloser stdout_read_closer(stdout_fds[kReadFD]);
502 if (!ChildLaunchedOK(exec_error_fds)) return v8::Undefined();
504 Handle<Value> accumulator = GetStdout(stdout_fds[kReadFD],
508 if (accumulator->IsUndefined()) {
509 kill(pid, SIGINT); // On timeout, kill the subprocess.
513 if (!WaitForChild(pid,
518 return v8::Undefined();
521 return scope.Close(accumulator);
525 Handle<Value> Shell::ChangeDirectory(const Arguments& args) {
526 if (args.Length() != 1) {
527 const char* message = "chdir() takes one argument";
528 return ThrowException(String::New(message));
530 String::Utf8Value directory(args[0]);
531 if (*directory == NULL) {
532 const char* message = "os.chdir(): String conversion of argument failed.";
533 return ThrowException(String::New(message));
535 if (chdir(*directory) != 0) {
536 return ThrowException(String::New(strerror(errno)));
538 return v8::Undefined();
542 Handle<Value> Shell::SetUMask(const Arguments& args) {
543 if (args.Length() != 1) {
544 const char* message = "umask() takes one argument";
545 return ThrowException(String::New(message));
547 if (args[0]->IsNumber()) {
548 mode_t mask = args[0]->Int32Value();
549 int previous = umask(mask);
550 return Number::New(previous);
552 const char* message = "umask() argument must be numeric";
553 return ThrowException(String::New(message));
558 static bool CheckItsADirectory(char* directory) {
559 struct stat stat_buf;
560 int stat_result = stat(directory, &stat_buf);
561 if (stat_result != 0) {
562 ThrowException(String::New(strerror(errno)));
565 if ((stat_buf.st_mode & S_IFDIR) != 0) return true;
566 ThrowException(String::New(strerror(EEXIST)));
571 // Returns true for success. Creates intermediate directories as needed. No
572 // error if the directory exists already.
573 static bool mkdirp(char* directory, mode_t mask) {
574 int result = mkdir(directory, mask);
575 if (result == 0) return true;
576 if (errno == EEXIST) {
577 return CheckItsADirectory(directory);
578 } else if (errno == ENOENT) { // Intermediate path element is missing.
579 char* last_slash = strrchr(directory, '/');
580 if (last_slash == NULL) {
581 ThrowException(String::New(strerror(errno)));
585 if (!mkdirp(directory, mask)) return false;
587 result = mkdir(directory, mask);
588 if (result == 0) return true;
589 if (errno == EEXIST) {
590 return CheckItsADirectory(directory);
592 ThrowException(String::New(strerror(errno)));
595 ThrowException(String::New(strerror(errno)));
601 Handle<Value> Shell::MakeDirectory(const Arguments& args) {
603 if (args.Length() == 2) {
604 if (args[1]->IsNumber()) {
605 mask = args[1]->Int32Value();
607 const char* message = "mkdirp() second argument must be numeric";
608 return ThrowException(String::New(message));
610 } else if (args.Length() != 1) {
611 const char* message = "mkdirp() takes one or two arguments";
612 return ThrowException(String::New(message));
614 String::Utf8Value directory(args[0]);
615 if (*directory == NULL) {
616 const char* message = "os.mkdirp(): String conversion of argument failed.";
617 return ThrowException(String::New(message));
619 mkdirp(*directory, mask);
620 return v8::Undefined();
624 Handle<Value> Shell::RemoveDirectory(const Arguments& args) {
625 if (args.Length() != 1) {
626 const char* message = "rmdir() takes one or two arguments";
627 return ThrowException(String::New(message));
629 String::Utf8Value directory(args[0]);
630 if (*directory == NULL) {
631 const char* message = "os.rmdir(): String conversion of argument failed.";
632 return ThrowException(String::New(message));
635 return v8::Undefined();
639 Handle<Value> Shell::SetEnvironment(const Arguments& args) {
640 if (args.Length() != 2) {
641 const char* message = "setenv() takes two arguments";
642 return ThrowException(String::New(message));
644 String::Utf8Value var(args[0]);
645 String::Utf8Value value(args[1]);
647 const char* message =
648 "os.setenv(): String conversion of variable name failed.";
649 return ThrowException(String::New(message));
651 if (*value == NULL) {
652 const char* message =
653 "os.setenv(): String conversion of variable contents failed.";
654 return ThrowException(String::New(message));
656 setenv(*var, *value, 1);
657 return v8::Undefined();
661 Handle<Value> Shell::UnsetEnvironment(const Arguments& args) {
662 if (args.Length() != 1) {
663 const char* message = "unsetenv() takes one argument";
664 return ThrowException(String::New(message));
666 String::Utf8Value var(args[0]);
668 const char* message =
669 "os.setenv(): String conversion of variable name failed.";
670 return ThrowException(String::New(message));
673 return v8::Undefined();
677 void Shell::AddOSMethods(Handle<ObjectTemplate> os_templ) {
678 os_templ->Set(String::New("system"), FunctionTemplate::New(System));
679 os_templ->Set(String::New("chdir"), FunctionTemplate::New(ChangeDirectory));
680 os_templ->Set(String::New("setenv"), FunctionTemplate::New(SetEnvironment));
681 os_templ->Set(String::New("unsetenv"),
682 FunctionTemplate::New(UnsetEnvironment));
683 os_templ->Set(String::New("umask"), FunctionTemplate::New(SetUMask));
684 os_templ->Set(String::New("mkdirp"), FunctionTemplate::New(MakeDirectory));
685 os_templ->Set(String::New("rmdir"), FunctionTemplate::New(RemoveDirectory));