1 files changed, 415 insertions, 0 deletions
diff --git a/src/modules/mavlink/mavlink_ftp.cpp b/src/modules/mavlink/mavlink_ftp.cpp
new file mode 100644
index 000000000..ca846a465
--- /dev/null
+++ b/src/modules/mavlink/mavlink_ftp.cpp
@@ -0,0 +1,415 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include <crc32.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#include "mavlink_ftp.h"
+
+MavlinkFTP *MavlinkFTP::_server;
+
+MavlinkFTP *
+MavlinkFTP::getServer()
+{
+	// XXX this really cries out for some locking...
+	if (_server == nullptr) {
+		_server = new MavlinkFTP;
+	}
+	return _server;
+}
+
+MavlinkFTP::MavlinkFTP()
+{
+	// initialise the request freelist
+	dq_init(&_workFree);
+	sem_init(&_lock, 0, 1);
+    
+    // initialize session list
+    for (size_t i=0; i<kMaxSession; i++) {
+        _session_fds[i] = -1;
+    }
+
+	// drop work entries onto the free list
+	for (unsigned i = 0; i < kRequestQueueSize; i++) {
+		_qFree(&_workBufs[i]);
+	}
+
+}
+
+void
+MavlinkFTP::handle_message(Mavlink* mavlink, mavlink_message_t *msg)
+{
+	// get a free request
+	auto req = _dqFree();
+
+	// if we couldn't get a request slot, just drop it
+	if (req != nullptr) {
+
+		// decode the request
+		if (req->decode(mavlink, msg)) {
+
+			// and queue it for the worker
+			work_queue(LPWORK, &req->work, &MavlinkFTP::_workerTrampoline, req, 0);
+		} else {
+			_qFree(req);
+		}
+	}
+}
+
+void
+MavlinkFTP::_workerTrampoline(void *arg)
+{
+	auto req = reinterpret_cast<Request *>(arg);
+	auto server = MavlinkFTP::getServer();
+
+	// call the server worker with the work item
+	server->_worker(req);
+}
+
+void
+MavlinkFTP::_worker(Request *req)
+{
+	auto hdr = req->header();
+	ErrorCode errorCode = kErrNone;
+	uint32_t messageCRC;
+
+	// basic sanity checks; must validate length before use
+	if ((hdr->magic != kProtocolMagic) || (hdr->size > kMaxDataLength)) {
+		errorCode = kErrNoRequest;
+		goto out;
+	}
+
+	// check request CRC to make sure this is one of ours
+	messageCRC = hdr->crc32;
+	hdr->crc32 = 0;
+	if (crc32(req->rawData(), req->dataSize()) != messageCRC) {
+		errorCode = kErrNoRequest;
+		goto out;
+		printf("ftp: bad crc\n");
+	}
+
+	printf("ftp: channel %u opc %u size %u offset %u\n", req->channel(), hdr->opcode, hdr->size, hdr->offset);
+
+	switch (hdr->opcode) {
+	case kCmdNone:
+		break;
+
+	case kCmdTerminate:
+		errorCode = _workTerminate(req);
+		break;
+
+	case kCmdReset:
+		errorCode = _workReset();
+		break;
+
+	case kCmdList:
+		errorCode = _workList(req);
+		break;
+
+	case kCmdOpen:
+		errorCode = _workOpen(req, false);
+		break;
+
+	case kCmdCreate:
+		errorCode = _workOpen(req, true);
+		break;
+
+	case kCmdRead:
+		errorCode = _workRead(req);
+		break;
+
+	case kCmdWrite:
+		errorCode = _workWrite(req);
+		break;
+
+	case kCmdRemove:
+		errorCode = _workRemove(req);
+		break;
+
+	default:
+		errorCode = kErrNoRequest;
+		break;	
+	}
+
+out:
+	// handle success vs. error
+	if (errorCode == kErrNone) {
+		hdr->opcode = kRspAck;
+		printf("FTP: ack\n");
+	} else {
+		printf("FTP: nak %u\n", errorCode);
+		hdr->opcode = kRspNak;
+		hdr->size = 1;
+		hdr->data[0] = errorCode;
+	}
+
+	// respond to the request
+	_reply(req);
+
+	// free the request buffer back to the freelist
+	_qFree(req);
+}
+
+void
+MavlinkFTP::_reply(Request *req)
+{
+	auto hdr = req->header();
+
+	// message is assumed to be already constructed in the request buffer, so generate the CRC
+	hdr->crc32 = 0;
+	hdr->crc32 = crc32(req->rawData(), req->dataSize());
+
+	// then pack and send the reply back to the request source
+	req->reply();
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workList(Request *req)
+{
+	auto hdr = req->header();
+	DIR *dp = opendir(req->dataAsCString());
+
+	if (dp == nullptr) {
+		printf("FTP: can't open path '%s'\n", req->dataAsCString());
+		return kErrNotDir;
+	}
+
+	ErrorCode errorCode = kErrNone;
+	struct dirent entry, *result = nullptr;
+	unsigned offset = 0;
+
+	// move to the requested offset
+	seekdir(dp, hdr->offset);
+
+	for (;;) {
+		// read the directory entry
+		if (readdir_r(dp, &entry, &result)) {
+			errorCode = kErrIO;
+			break;
+		}
+
+		// no more entries?
+		if (result == nullptr) {
+			if (hdr->offset != 0 && offset == 0) {
+				// User is requesting subsequent dir entries but there were none. This means the user asked
+				// to seek past EOF.
+				errorCode = kErrEOF;
+			}
+			// Otherwise we are just at the last directory entry, so we leave the errorCode at kErrorNone to signal that
+			break;
+		}
+
+		// name too big to fit?
+		if ((strlen(entry.d_name) + offset + 2) > kMaxDataLength) {
+			break;
+		}
+
+		// store the type marker
+		switch (entry.d_type) {
+		case DTYPE_FILE:
+			hdr->data[offset++] = kDirentFile;
+			break;
+		case DTYPE_DIRECTORY:
+			hdr->data[offset++] = kDirentDir;
+			break;
+		default:
+			hdr->data[offset++] = kDirentUnknown;
+			break;
+		}
+
+		// copy the name, which we know will fit
+		strcpy((char *)&hdr->data[offset], entry.d_name);
+		offset += strlen(entry.d_name) + 1;
+		printf("FTP: list %s\n", entry.d_name);
+	}
+
+	closedir(dp);
+	hdr->size = offset;
+
+	return errorCode;
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workOpen(Request *req, bool create)
+{
+	auto hdr = req->header();
+    
+	int session_index = _findUnusedSession();
+	if (session_index < 0) {
+		return kErrNoSession;
+	}
+
+	int oflag = create ? (O_CREAT | O_EXCL | O_APPEND) : O_RDONLY;
+    
+	int fd = ::open(req->dataAsCString(), oflag);
+	if (fd < 0) {
+		return create ? kErrPerm : kErrNotFile;
+	}
+	_session_fds[session_index] = fd;
+
+	hdr->session = session_index;
+	hdr->size = 0;
+
+	return kErrNone;
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workRead(Request *req)
+{
+	auto hdr = req->header();
+
+	int session_index = hdr->session;
+
+	if (!_validSession(session_index)) {
+		return kErrNoSession;
+	}
+
+	// Seek to the specified position
+	printf("Seek %d\n", hdr->offset);
+	if (lseek(_session_fds[session_index], hdr->offset, SEEK_SET) < 0) {
+		// Unable to see to the specified location
+		return kErrEOF;
+	}
+
+	int bytes_read = ::read(_session_fds[session_index], &hdr->data[0], kMaxDataLength);
+	if (bytes_read < 0) {
+		// Negative return indicates error other than eof
+		return kErrIO;
+	}
+
+	printf("Read success %d\n", bytes_read);
+	hdr->size = bytes_read;
+
+	return kErrNone;
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workWrite(Request *req)
+{
+#if 0
+    // NYI: Coming soon
+	auto hdr = req->header();
+
+	// look up session
+	auto session = getSession(hdr->session);
+	if (session == nullptr) {
+		return kErrNoSession;
+	}
+
+	// append to file
+	int result = session->append(hdr->offset, &hdr->data[0], hdr->size);
+
+	if (result < 0) {
+		// XXX might also be no space, I/O, etc.
+		return kErrNotAppend;
+	}
+
+	hdr->size = result;
+	return kErrNone;
+#else
+	return kErrPerm;
+#endif
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workRemove(Request *req)
+{
+	auto hdr = req->header();
+
+	// for now, send error reply
+	return kErrPerm;
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workTerminate(Request *req)
+{
+	auto hdr = req->header();
+    
+	if (!_validSession(hdr->session)) {
+		return kErrNoSession;
+	}
+    
+	::close(_session_fds[hdr->session]);
+
+	return kErrNone;
+}
+
+MavlinkFTP::ErrorCode
+MavlinkFTP::_workReset(void)
+{
+	for (size_t i=0; i<kMaxSession; i++) {
+		if (_session_fds[i] != -1) {
+			::close(_session_fds[i]);
+			_session_fds[i] = -1;
+		}
+	}
+
+	return kErrNone;
+}
+
+bool
+MavlinkFTP::_validSession(unsigned index)
+{
+	if ((index >= kMaxSession) || (_session_fds[index] < 0)) {
+		return false;
+	}
+	return true;
+}
+
+int
+MavlinkFTP::_findUnusedSession(void)
+{
+	for (size_t i=0; i<kMaxSession; i++) {
+		if (_session_fds[i] == -1) {
+			return i;
+		}
+	}
+
+	return -1;
+}
+
+char *
+MavlinkFTP::Request::dataAsCString()
+{
+	// guarantee nul termination
+	if (header()->size < kMaxDataLength) {
+		requestData()[header()->size] = '\0';
+	} else {
+		requestData()[kMaxDataLength - 1] = '\0';
+	}
+
+	// and return data
+	return (char *)&(header()->data[0]);
+}