michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0:  */
michael@0: 
michael@0: /*
michael@0:  * ChromeWorker Object subprocess.jsm on Unix-like systems (Linux, Mac OS X, ...)
michael@0:  * to process stdin/stdout/stderr on separate threads.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: // Being a ChromeWorker object, implicitly uses the following:
michael@0: // Components.utils.import("resource://gre/modules/ctypes.jsm");
michael@0: 
michael@0: 'use strict';
michael@0: 
michael@0: const BufferSize = 1024;
michael@0: 
michael@0: var libc = null;
michael@0: var libcFunc = {};
michael@0: 
michael@0: 
michael@0: /*
michael@0:     struct pollfd {
michael@0:          int    fd;       // file descriptor
michael@0:          short  events;   // events to look for
michael@0:          short  revents;  // events returned
michael@0:      };
michael@0: */
michael@0: 
michael@0: var pollfd = new ctypes.StructType("pollfd",
michael@0:                         [   {'fd': ctypes.int},
michael@0:                             {'events': ctypes.short},
michael@0:                             {'revents': ctypes.short}
michael@0:                         ]);
michael@0: 
michael@0: var WriteBuffer = ctypes.uint8_t.array(BufferSize);
michael@0: var ReadBuffer = ctypes.char.array(BufferSize);
michael@0: 
michael@0: 
michael@0: const POLLIN     = 0x0001;
michael@0: const POLLOUT    = 0x0004;
michael@0: 
michael@0: const POLLERR    = 0x0008;         // some poll error occurred
michael@0: const POLLHUP    = 0x0010;         // file descriptor was "hung up"
michael@0: const POLLNVAL   = 0x0020;         // requested events "invalid"
michael@0: 
michael@0: const WNOHANG    = 0x01;
michael@0: 
michael@0: const pid_t = ctypes.int32_t;
michael@0: 
michael@0: const INDEFINITE = -1;
michael@0: const NOWAIT     = 0;
michael@0: const WAITTIME   = 200  // wait time for poll() in ms
michael@0: 
michael@0: function initLibc(libName) {
michael@0:     postMessage({msg: "debug", data: "initialising library with "+ libName});
michael@0: 
michael@0:     libc = ctypes.open(libName);
michael@0: 
michael@0:     libcFunc.pollFds = pollfd.array(1);
michael@0: 
michael@0:     // int poll(struct pollfd fds[], nfds_t nfds, int timeout);
michael@0:     libcFunc.poll = libc.declare("poll",
michael@0:                                   ctypes.default_abi,
michael@0:                                   ctypes.int,
michael@0:                                   libcFunc.pollFds,
michael@0:                                   ctypes.unsigned_int,
michael@0:                                   ctypes.int);
michael@0: 
michael@0:     //ssize_t write(int fd, const void *buf, size_t count);
michael@0:     // NOTE: buf is declared as array of unsigned int8 instead of char to avoid
michael@0:     // implicit charset conversion
michael@0:     libcFunc.write = libc.declare("write",
michael@0:                                   ctypes.default_abi,
michael@0:                                   ctypes.int,
michael@0:                                   ctypes.int,
michael@0:                                   WriteBuffer,
michael@0:                                   ctypes.int);
michael@0: 
michael@0:     //int read(int fd, void *buf, size_t count);
michael@0:     libcFunc.read = libc.declare("read",
michael@0:                                   ctypes.default_abi,
michael@0:                                   ctypes.int,
michael@0:                                   ctypes.int,
michael@0:                                   ReadBuffer,
michael@0:                                   ctypes.int);
michael@0: 
michael@0:     //int pipe(int pipefd[2]);
michael@0:     libcFunc.pipefd = ctypes.int.array(2);
michael@0: 
michael@0:     //int close(int fd);
michael@0:     libcFunc.close = libc.declare("close",
michael@0:                                   ctypes.default_abi,
michael@0:                                   ctypes.int,
michael@0:                                   ctypes.int);
michael@0: 
michael@0:     //pid_t waitpid(pid_t pid, int *status, int options);
michael@0:     libcFunc.waitpid = libc.declare("waitpid",
michael@0:                                   ctypes.default_abi,
michael@0:                                   pid_t,
michael@0:                                   pid_t,
michael@0:                                   ctypes.int.ptr,
michael@0:                                   ctypes.int);
michael@0: }
michael@0: 
michael@0: function closePipe(pipe) {
michael@0:     libcFunc.close(pipe);
michael@0: }
michael@0: 
michael@0: function writePipe(pipe, data) {
michael@0: 
michael@0:     postMessage({msg: "debug", data: "trying to write to "+pipe});
michael@0: 
michael@0:     let numChunks = Math.floor(data.length / BufferSize);
michael@0:     let pData = new WriteBuffer();
michael@0: 
michael@0:     for (var chunk = 0; chunk <= numChunks; chunk ++) {
michael@0:         let numBytes = chunk < numChunks ? BufferSize : data.length - chunk * BufferSize;
michael@0:         for (var i=0; i < numBytes; i++) {
michael@0:             pData[i] = data.charCodeAt(chunk * BufferSize + i) % 256;
michael@0:         }
michael@0: 
michael@0:         let bytesWritten = libcFunc.write(pipe, pData, numBytes);
michael@0:         if (bytesWritten != numBytes) {
michael@0:             closePipe();
michael@0:             libc.close();
michael@0:             postMessage({ msg: "error", data: "error: wrote "+bytesWritten+" instead of "+numBytes+" bytes"});
michael@0:             close();
michael@0:         }
michael@0:     }
michael@0:     postMessage({msg: "info", data: "wrote "+data.length+" bytes of data"});
michael@0: }
michael@0: 
michael@0: 
michael@0: function readString(data, length, charset) {
michael@0:     var string = '', bytes = [];
michael@0:     for(var i = 0;i < length; i++) {
michael@0:         if(data[i] == 0 && charset != "null") // stop on NULL character for non-binary data
michael@0:            break;
michael@0: 
michael@0:         bytes.push(data[i]);
michael@0:     }
michael@0: 
michael@0:     return bytes;
michael@0: }
michael@0: 
michael@0: function readPipe(pipe, charset, pid) {
michael@0:     var p = new libcFunc.pollFds;
michael@0:     p[0].fd = pipe;
michael@0:     p[0].events = POLLIN | POLLERR | POLLHUP;
michael@0:     p[0].revents = 0;
michael@0:     var pollTimeout = WAITTIME;
michael@0:     var exitCode = -1;
michael@0:     var readCount = 0;
michael@0:     var result, status = ctypes.int();
michael@0:     result = 0;
michael@0: 
michael@0: 
michael@0:     const i=0;
michael@0:     while (true) {
michael@0:         if (result == 0) {
michael@0:             result = libcFunc.waitpid(pid, status.address(), WNOHANG);
michael@0:             if (result > 0) {
michael@0:                 pollTimeout = NOWAIT;
michael@0:                 exitCode = parseInt(status.value);
michael@0:                 postMessage({msg: "debug", data: "waitpid signaled subprocess stop, exitcode="+status.value });
michael@0:             }
michael@0:         }
michael@0:         var r = libcFunc.poll(p, 1, pollTimeout);
michael@0:         if (r > 0) {
michael@0:             if (p[i].revents & POLLIN) {
michael@0:                 postMessage({msg: "debug", data: "reading next chunk"});
michael@0:                 readCount = readPolledFd(p[i].fd, charset);
michael@0:                 if (readCount == 0) break;
michael@0:             }
michael@0: 
michael@0:             if (p[i].revents & POLLHUP) {
michael@0:                 postMessage({msg: "debug", data: "poll returned HUP"});
michael@0:                 break;
michael@0:             }
michael@0:             else if (p[i].revents & POLLERR) {
michael@0:                 postMessage({msg: "error", data: "poll returned error"});
michael@0:                 break;
michael@0:             }
michael@0:             else if (p[i].revents != POLLIN) {
michael@0:                 postMessage({msg: "error", data: "poll returned "+p[i]});
michael@0:                 break;
michael@0:             }
michael@0:         }
michael@0:         else
michael@0:             if (pollTimeout == 0 || r < 0) break;
michael@0:     }
michael@0: 
michael@0:     // continue reading until the buffer is empty
michael@0:     while (readCount > 0) {
michael@0:       readCount = readPolledFd(pipe, charset);
michael@0:     }
michael@0: 
michael@0:     libcFunc.close(pipe);
michael@0:     postMessage({msg: "done", data: exitCode });
michael@0:     libc.close();
michael@0:     close();
michael@0: }
michael@0: 
michael@0: function readPolledFd(pipe, charset) {
michael@0:     var line = new ReadBuffer();
michael@0:     var r = libcFunc.read(pipe, line, BufferSize);
michael@0: 
michael@0:     if (r > 0) {
michael@0:         var c = readString(line, r, charset);
michael@0:         postMessage({msg: "data", data: c, count: c.length});
michael@0:     }
michael@0:     return r;
michael@0: }
michael@0: 
michael@0: onmessage = function (event) {
michael@0:     switch (event.data.msg) {
michael@0:     case "init":
michael@0:         initLibc(event.data.libc);
michael@0:         break;
michael@0:     case "read":
michael@0:         initLibc(event.data.libc);
michael@0:         readPipe(event.data.pipe, event.data.charset, event.data.pid);
michael@0:         break;
michael@0:     case "write":
michael@0:         // data contents:
michael@0:         //   msg: 'write'
michael@0:         //   data: the data (string) to write
michael@0:         //   pipe: ptr to pipe
michael@0:         writePipe(event.data.pipe, event.data.data);
michael@0:         postMessage({msg: "info", data: "WriteOK"});
michael@0:         break;
michael@0:     case "close":
michael@0:         postMessage({msg: "debug", data: "closing stdin\n"});
michael@0: 
michael@0:         closePipe(event.data.pipe);
michael@0:         postMessage({msg: "info", data: "ClosedOK"});
michael@0:         break;
michael@0:     case "stop":
michael@0:         libc.close(); // do not use libc after this point
michael@0:         close();
michael@0:         break;
michael@0:     default:
michael@0:         throw("error: Unknown command"+event.data.msg+"\n");
michael@0:     }
michael@0:     return;
michael@0: };