1 /*
2 * Copyright (c) 1998 Adrian Sun (asun@zoology.washington.edu)
3 * Copyright (c) 2010,2011,2012 Frank Lahm <franklahm@googlemail.com>
4 > * All rights reserved. See COPYRIGHT.
5 *
6 * this file provides the following functions:
7 * dsi_stream_write: just write a bunch of bytes.
8 * dsi_stream_read: just read a bunch of bytes.
9 * dsi_stream_send: send a DSI header + data.
10 * dsi_stream_receive: read a DSI header + data.
11 */
12
13 #ifdef HAVE_CONFIG_H
14 #include "config.h"
15 #endif /* HAVE_CONFIG_H */
16
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <unistd.h>
20 #include <string.h>
21 #include <errno.h>
22 #include <sys/types.h>
23 #include <sys/socket.h>
24 #include <sys/uio.h>
25
26 #ifdef HAVE_SENDFILEV
27 #include <sys/sendfile.h>
28 #endif
29
30 #include <atalk/logger.h>
31 #include <atalk/dsi.h>
32 #include <atalk/util.h>
33
34 #ifndef MSG_MORE
35 #define MSG_MORE 0x8000
36 #endif
37
38 #ifndef MSG_DONTWAIT
39 #define MSG_DONTWAIT 0x40
40 #endif
41
42 /* Pack a DSI header in wire format */
dsi_header_pack_reply(const DSI * dsi,char * buf)43 static void dsi_header_pack_reply(const DSI *dsi, char *buf)
44 {
45 buf[0] = dsi->header.dsi_flags;
46 buf[1] = dsi->header.dsi_command;
47 memcpy(buf + 2, &dsi->header.dsi_requestID, sizeof(dsi->header.dsi_requestID));
48 memcpy(buf + 4, &dsi->header.dsi_data.dsi_code, sizeof(dsi->header.dsi_data.dsi_code));
49 memcpy(buf + 8, &dsi->header.dsi_len, sizeof(dsi->header.dsi_len));
50 memcpy(buf + 12, &dsi->header.dsi_reserved, sizeof(dsi->header.dsi_reserved));
51 }
52
53 /*
54 * afpd is sleeping too much while trying to send something.
55 * May be there's no reader or the reader is also sleeping in write,
56 * look if there's some data for us to read, hopefully it will wake up
57 * the reader so we can write again.
58 *
59 * @returns 0 when is possible to send again, -1 on error
60 */
dsi_peek(DSI * dsi)61 static int dsi_peek(DSI *dsi)
62 {
63 static int warned = 0;
64 fd_set readfds, writefds;
65 int len;
66 int maxfd;
67 int ret;
68
69 LOG(log_debug, logtype_dsi, "dsi_peek");
70
71 maxfd = dsi->socket + 1;
72
73 while (1) {
74 if (dsi->socket == -1)
75 /* eg dsi_disconnect() might have disconnected us */
76 return -1;
77 FD_ZERO(&readfds);
78 FD_ZERO(&writefds);
79
80 if (dsi->eof < dsi->end) {
81 /* space in read buffer */
82 FD_SET( dsi->socket, &readfds);
83 } else {
84 if (!warned) {
85 warned = 1;
86 LOG(log_note, logtype_dsi, "dsi_peek: readahead buffer is full, possibly increase -dsireadbuf option");
87 LOG(log_note, logtype_dsi, "dsi_peek: dsireadbuf: %d, DSI quantum: %d, effective buffer size: %d",
88 dsi->dsireadbuf,
89 dsi->server_quantum ? dsi->server_quantum : DSI_SERVQUANT_DEF,
90 dsi->end - dsi->buffer);
91 }
92 }
93
94 FD_SET( dsi->socket, &writefds);
95
96 /* No timeout: if there's nothing to read nor nothing to write,
97 * we've got nothing to do at all */
98 if ((ret = select( maxfd, &readfds, &writefds, NULL, NULL)) <= 0) {
99 if (ret == -1 && errno == EINTR)
100 /* we might have been interrupted by out timer, so restart select */
101 continue;
102 /* give up */
103 LOG(log_error, logtype_dsi, "dsi_peek: unexpected select return: %d %s",
104 ret, ret < 0 ? strerror(errno) : "");
105 return -1;
106 }
107
108 if (FD_ISSET(dsi->socket, &writefds)) {
109 /* we can write again */
110 LOG(log_debug, logtype_dsi, "dsi_peek: can write again");
111 break;
112 }
113
114 /* Check if there's sth to read, hopefully reading that will unblock the client */
115 if (FD_ISSET(dsi->socket, &readfds)) {
116 len = dsi->end - dsi->eof; /* it's ensured above that there's space */
117
118 if ((len = recv(dsi->socket, dsi->eof, len, 0)) <= 0) {
119 if (len == 0) {
120 LOG(log_error, logtype_dsi, "dsi_peek: EOF");
121 return -1;
122 }
123 LOG(log_error, logtype_dsi, "dsi_peek: read: %s", strerror(errno));
124 if (errno == EAGAIN)
125 continue;
126 return -1;
127 }
128 LOG(log_debug, logtype_dsi, "dsi_peek: read %d bytes", len);
129
130 dsi->eof += len;
131 }
132 }
133
134 return 0;
135 }
136
137 /*
138 * Return all bytes up to count from dsi->buffer if there are any buffered there
139 */
from_buf(DSI * dsi,uint8_t * buf,size_t count)140 static size_t from_buf(DSI *dsi, uint8_t *buf, size_t count)
141 {
142 size_t nbe = 0;
143
144 if (dsi->buffer == NULL)
145 /* afpd master has no DSI buffering */
146 return 0;
147
148 LOG(log_maxdebug, logtype_dsi, "from_buf: %u bytes", count);
149
150 nbe = dsi->eof - dsi->start;
151
152 if (nbe > 0) {
153 nbe = MIN((size_t)nbe, count);
154 memcpy(buf, dsi->start, nbe);
155 dsi->start += nbe;
156
157 if (dsi->eof == dsi->start)
158 dsi->start = dsi->eof = dsi->buffer;
159 }
160
161 LOG(log_debug, logtype_dsi, "from_buf(read: %u, unread:%u , space left: %u): returning %u",
162 dsi->start - dsi->buffer, dsi->eof - dsi->start, dsi->end - dsi->eof, nbe);
163
164 return nbe;
165 }
166
167 /*
168 * Get bytes from buffer dsi->buffer or read from socket
169 *
170 * 1. Check if there are bytes in the the dsi->buffer buffer.
171 * 2. Return bytes from (1) if yes.
172 * Note: this may return fewer bytes then requested in count !!
173 * 3. If the buffer was empty, read from the socket.
174 */
buf_read(DSI * dsi,uint8_t * buf,size_t count)175 static ssize_t buf_read(DSI *dsi, uint8_t *buf, size_t count)
176 {
177 ssize_t len;
178
179 LOG(log_maxdebug, logtype_dsi, "buf_read(%u bytes)", count);
180
181 if (!count)
182 return 0;
183
184 len = from_buf(dsi, buf, count); /* 1. */
185 if (len)
186 return len; /* 2. */
187
188 len = readt(dsi->socket, buf, count, 0, 0); /* 3. */
189
190 LOG(log_maxdebug, logtype_dsi, "buf_read(%u bytes): got: %d", count, len);
191
192 return len;
193 }
194
195 /*
196 * Get "length" bytes from buffer and/or socket. In order to avoid frequent small reads
197 * this tries to read larger chunks (8192 bytes) into a buffer.
198 */
dsi_buffered_stream_read(DSI * dsi,uint8_t * data,const size_t length)199 static size_t dsi_buffered_stream_read(DSI *dsi, uint8_t *data, const size_t length)
200 {
201 size_t len;
202 size_t buflen;
203
204 LOG(log_maxdebug, logtype_dsi, "dsi_buffered_stream_read: %u bytes", length);
205
206 len = from_buf(dsi, data, length); /* read from buffer dsi->buffer */
207 dsi->read_count += len;
208 if (len == length) { /* got enough bytes from there ? */
209 return len; /* yes */
210 }
211
212 /* fill the buffer with 8192 bytes or until buffer is full */
213 buflen = MIN(8192, dsi->end - dsi->eof);
214 if (buflen > 0) {
215 ssize_t ret;
216 ret = recv(dsi->socket, dsi->eof, buflen, 0);
217 if (ret > 0)
218 dsi->eof += ret;
219 }
220
221 /* now get the remaining data */
222 if ((buflen = dsi_stream_read(dsi, data + len, length - len)) != length - len)
223 return 0;
224 len += buflen;
225
226 return len;
227 }
228
229 /* ---------------------------------------
230 */
block_sig(DSI * dsi)231 static void block_sig(DSI *dsi)
232 {
233 dsi->in_write++;
234 }
235
236 /* ---------------------------------------
237 */
unblock_sig(DSI * dsi)238 static void unblock_sig(DSI *dsi)
239 {
240 dsi->in_write--;
241 }
242
243 /*********************************************************************************
244 * Public functions
245 *********************************************************************************/
246
247 /*!
248 * Communication error with the client, enter disconnected state
249 *
250 * 1. close the socket
251 * 2. set the DSI_DISCONNECTED flag, remove possible sleep flags
252 *
253 * @returns 0 if successfully entered disconnected state
254 * -1 if ppid is 1 which means afpd master died
255 * or euid == 0 ie where still running as root (unauthenticated session)
256 */
dsi_disconnect(DSI * dsi)257 int dsi_disconnect(DSI *dsi)
258 {
259 LOG(log_note, logtype_dsi, "dsi_disconnect: entering disconnected state");
260 dsi->proto_close(dsi); /* 1 */
261 dsi->flags &= ~(DSI_SLEEPING | DSI_EXTSLEEP); /* 2 */
262 dsi->flags |= DSI_DISCONNECTED;
263 if (geteuid() == 0)
264 return -1;
265 return 0;
266 }
267
268 /* ------------------------------
269 * write raw data. return actual bytes read. checks against EINTR
270 * aren't necessary if all of the signals have SA_RESTART
271 * specified. */
dsi_stream_write(DSI * dsi,void * data,const size_t length,int mode)272 ssize_t dsi_stream_write(DSI *dsi, void *data, const size_t length, int mode)
273 {
274 size_t written;
275 ssize_t len;
276 unsigned int flags;
277
278 dsi->in_write++;
279 written = 0;
280
281 LOG(log_maxdebug, logtype_dsi, "dsi_stream_write(send: %zd bytes): START", length);
282
283 if (dsi->flags & DSI_DISCONNECTED)
284 return -1;
285
286 if (mode & DSI_MSG_MORE)
287 flags = MSG_MORE;
288 else
289 flags = 0;
290
291 while (written < length) {
292 len = send(dsi->socket, (uint8_t *) data + written, length - written, flags);
293 if (len >= 0) {
294 written += len;
295 continue;
296 }
297
298 if (errno == EINTR)
299 continue;
300
301 if (errno == EAGAIN || errno == EWOULDBLOCK) {
302 LOG(log_debug, logtype_dsi, "dsi_stream_write: send: %s", strerror(errno));
303
304 if (mode == DSI_NOWAIT && written == 0) {
305 /* DSI_NOWAIT is used by attention give up in this case. */
306 written = -1;
307 goto exit;
308 }
309
310 /* Try to read sth. in order to break up possible deadlock */
311 if (dsi_peek(dsi) != 0) {
312 written = -1;
313 goto exit;
314 }
315 /* Now try writing again */
316 continue;
317 }
318
319 LOG(log_error, logtype_dsi, "dsi_stream_write: %s", strerror(errno));
320 written = -1;
321 goto exit;
322 }
323
324 dsi->write_count += written;
325 LOG(log_maxdebug, logtype_dsi, "dsi_stream_write(send: %zd bytes): END", length);
326
327 exit:
328 dsi->in_write--;
329 return written;
330 }
331
332 /* ---------------------------------
333 */
334 #ifdef WITH_SENDFILE
dsi_stream_read_file(DSI * dsi,const int fromfd,off_t offset,const size_t length,const int err)335 ssize_t dsi_stream_read_file(DSI *dsi, const int fromfd, off_t offset, const size_t length, const int err)
336 {
337 int ret = 0;
338 size_t written = 0;
339 size_t total = length;
340 ssize_t len;
341 off_t pos = offset;
342 char block[DSI_BLOCKSIZ];
343 #ifdef HAVE_SENDFILEV
344 int sfvcnt;
345 struct sendfilevec vec[2];
346 ssize_t nwritten;
347 #elif defined(FREEBSD)
348 ssize_t nwritten;
349 void *hdrp;
350 struct sf_hdtr hdr;
351 struct iovec iovec;
352 hdr.headers = &iovec;
353 hdr.hdr_cnt = 1;
354 hdr.trailers = NULL;
355 hdr.trl_cnt = 0;
356 hdrp = &hdr;
357 #endif
358
359 LOG(log_maxdebug, logtype_dsi, "dsi_stream_read_file(off: %jd, len: %zu)", (intmax_t)offset, length);
360
361 if (dsi->flags & DSI_DISCONNECTED)
362 return -1;
363
364 dsi->in_write++;
365
366 dsi->flags |= DSI_NOREPLY;
367 dsi->header.dsi_flags = DSIFL_REPLY;
368 dsi->header.dsi_len = htonl(length);
369 dsi->header.dsi_data.dsi_code = htonl(err);
370 dsi_header_pack_reply(dsi, block);
371
372 #ifdef HAVE_SENDFILEV
373 total += DSI_BLOCKSIZ;
374 sfvcnt = 2;
375 vec[0].sfv_fd = SFV_FD_SELF;
376 vec[0].sfv_flag = 0;
377 /* Cast to unsigned long to prevent sign extension of the
378 * pointer value for the LFS case; see Apache PR 39463. */
379 vec[0].sfv_off = (unsigned long)block;
380 vec[0].sfv_len = DSI_BLOCKSIZ;
381 vec[1].sfv_fd = fromfd;
382 vec[1].sfv_flag = 0;
383 vec[1].sfv_off = offset;
384 vec[1].sfv_len = length;
385 #elif defined(FREEBSD)
386 iovec.iov_base = block;
387 iovec.iov_len = DSI_BLOCKSIZ;
388 #else
389 dsi_stream_write(dsi, block, sizeof(block), DSI_MSG_MORE);
390 #endif
391
392 while (written < total) {
393 #ifdef HAVE_SENDFILEV
394 nwritten = 0;
395 len = sendfilev(dsi->socket, vec, sfvcnt, &nwritten);
396 #elif defined(FREEBSD)
397 len = sendfile(fromfd, dsi->socket, pos, total - written, hdrp, &nwritten, 0);
398 if (len == 0)
399 len = nwritten;
400 #else
401 len = sys_sendfile(dsi->socket, fromfd, &pos, total - written);
402 #endif
403 if (len < 0) {
404 switch (errno) {
405 case EINTR:
406 case EAGAIN:
407 len = 0;
408 #if defined(HAVE_SENDFILEV) || defined(FREEBSD)
409 len = (size_t)nwritten;
410 #elif defined(SOLARIS)
411 if (pos > offset) {
412 /* we actually have sent sth., adjust counters and keep trying */
413 len = pos - offset;
414 offset = pos;
415 }
416 #endif /* HAVE_SENDFILEV */
417
418 if (dsi_peek(dsi) != 0) {
419 ret = -1;
420 goto exit;
421 }
422 break;
423 default:
424 LOG(log_error, logtype_dsi, "dsi_stream_read_file: %s", strerror(errno));
425 ret = -1;
426 goto exit;
427 }
428 } else if (len == 0) {
429 /* afpd is going to exit */
430 ret = -1;
431 goto exit;
432 }
433 #ifdef HAVE_SENDFILEV
434 if (sfvcnt == 2 && len >= vec[0].sfv_len) {
435 vec[1].sfv_off += len - vec[0].sfv_len;
436 vec[1].sfv_len -= len - vec[0].sfv_len;
437
438 vec[0] = vec[1];
439 sfvcnt = 1;
440 } else {
441 vec[0].sfv_off += len;
442 vec[0].sfv_len -= len;
443 }
444 #elif defined(FREEBSD)
445 if (hdrp) {
446 if (len >= iovec.iov_len) {
447 hdrp = NULL;
448 len -= iovec.iov_len; /* len now contains how much sendfile() actually sent from the file */
449 } else {
450 iovec.iov_len -= len;
451 iovec.iov_base += len;
452 len = 0;
453 }
454 }
455 pos += len;
456 #endif /* HAVE_SENDFILEV */
457 LOG(log_maxdebug, logtype_dsi, "dsi_stream_read_file: wrote: %zd", len);
458 written += len;
459 }
460 #ifdef HAVE_SENDFILEV
461 written -= DSI_BLOCKSIZ;
462 #endif
463 dsi->write_count += written;
464
465 exit:
466 dsi->in_write--;
467 LOG(log_maxdebug, logtype_dsi, "dsi_stream_read_file: written: %zd", written);
468 if (ret != 0)
469 return -1;
470 return written;
471 }
472 #endif
473
474
475 /*
476 * Essentially a loop around buf_read() to ensure "length" bytes are read
477 * from dsi->buffer and/or the socket.
478 *
479 * @returns length on success, some value smaller then length indicates an error
480 */
dsi_stream_read(DSI * dsi,void * data,const size_t length)481 size_t dsi_stream_read(DSI *dsi, void *data, const size_t length)
482 {
483 size_t stored;
484 ssize_t len;
485
486 if (dsi->flags & DSI_DISCONNECTED)
487 return 0;
488
489 LOG(log_maxdebug, logtype_dsi, "dsi_stream_read(%u bytes)", length);
490
491 stored = 0;
492 while (stored < length) {
493 len = buf_read(dsi, (uint8_t *) data + stored, length - stored);
494 if (len == -1 && (errno == EINTR || errno == EAGAIN)) {
495 LOG(log_maxdebug, logtype_dsi, "dsi_stream_read: select read loop");
496 continue;
497 } else if (len > 0) {
498 stored += len;
499 } else { /* eof or error */
500 /* don't log EOF error if it's just after connect (OSX 10.3 probe) */
501 if (len || stored || dsi->read_count) {
502 if (! (dsi->flags & DSI_DISCONNECTED)) {
503 LOG(log_error, logtype_dsi, "dsi_stream_read: len:%d, %s",
504 len, (len < 0) ? strerror(errno) : "unexpected EOF");
505 }
506 return 0;
507 }
508 break;
509 }
510 }
511
512 dsi->read_count += stored;
513
514 LOG(log_maxdebug, logtype_dsi, "dsi_stream_read(%u bytes): got: %u", length, stored);
515 return stored;
516 }
517
518 /* ---------------------------------------
519 * write data. 0 on failure. this assumes that dsi_len will never
520 * cause an overflow in the data buffer.
521 */
dsi_stream_send(DSI * dsi,void * buf,size_t length)522 int dsi_stream_send(DSI *dsi, void *buf, size_t length)
523 {
524 char block[DSI_BLOCKSIZ];
525 struct iovec iov[2];
526 int iovecs = 2;
527 size_t towrite;
528 ssize_t len;
529
530 LOG(log_maxdebug, logtype_dsi, "dsi_stream_send(%u bytes): START", length);
531
532 if (dsi->flags & DSI_DISCONNECTED)
533 return 0;
534
535 dsi_header_pack_reply(dsi, block);
536
537 if (!length) { /* just write the header */
538 LOG(log_maxdebug, logtype_dsi, "dsi_stream_send(%u bytes): DSI header, no data", sizeof(block));
539 length = (dsi_stream_write(dsi, block, sizeof(block), 0) == sizeof(block));
540 return length; /* really 0 on failure, 1 on success */
541 }
542
543 /* block signals */
544 block_sig(dsi);
545 iov[0].iov_base = block;
546 iov[0].iov_len = sizeof(block);
547 iov[1].iov_base = buf;
548 iov[1].iov_len = length;
549
550 towrite = sizeof(block) + length;
551 dsi->write_count += towrite;
552 while (towrite > 0) {
553 if (((len = writev(dsi->socket, iov, iovecs)) == -1 && errno == EINTR) || (len == 0))
554 continue;
555
556 if ((size_t)len == towrite) /* wrote everything out */
557 break;
558 else if (len < 0) { /* error */
559 if (errno == EAGAIN || errno == EWOULDBLOCK) {
560 if (dsi_peek(dsi) == 0) {
561 continue;
562 }
563 }
564 LOG(log_error, logtype_dsi, "dsi_stream_send: %s", strerror(errno));
565 unblock_sig(dsi);
566 return 0;
567 }
568
569 towrite -= len;
570 if (towrite > length) { /* skip part of header */
571 iov[0].iov_base = (char *) iov[0].iov_base + len;
572 iov[0].iov_len -= len;
573 } else { /* skip to data */
574 if (iovecs == 2) {
575 iovecs = 1;
576 len -= iov[0].iov_len;
577 iov[0] = iov[1];
578 }
579 iov[0].iov_base = (char *) iov[0].iov_base + len;
580 iov[0].iov_len -= len;
581 }
582 }
583
584 LOG(log_maxdebug, logtype_dsi, "dsi_stream_send(%u bytes): END", length);
585
586 unblock_sig(dsi);
587 return 1;
588 }
589
590
591 /*!
592 * Read DSI command and data
593 *
594 * @param dsi (rw) DSI handle
595 *
596 * @return DSI function on success, 0 on failure
597 */
dsi_stream_receive(DSI * dsi)598 int dsi_stream_receive(DSI *dsi)
599 {
600 char block[DSI_BLOCKSIZ];
601
602 LOG(log_maxdebug, logtype_dsi, "dsi_stream_receive: START");
603
604 if (dsi->flags & DSI_DISCONNECTED)
605 return 0;
606
607 /* read in the header */
608 if (dsi_buffered_stream_read(dsi, (uint8_t *)block, sizeof(block)) != sizeof(block))
609 return 0;
610
611 dsi->header.dsi_flags = block[0];
612 dsi->header.dsi_command = block[1];
613
614 if (dsi->header.dsi_command == 0)
615 return 0;
616
617 memcpy(&dsi->header.dsi_requestID, block + 2, sizeof(dsi->header.dsi_requestID));
618 memcpy(&dsi->header.dsi_data.dsi_doff, block + 4, sizeof(dsi->header.dsi_data.dsi_doff));
619 dsi->header.dsi_data.dsi_doff = htonl(dsi->header.dsi_data.dsi_doff);
620 memcpy(&dsi->header.dsi_len, block + 8, sizeof(dsi->header.dsi_len));
621
622 memcpy(&dsi->header.dsi_reserved, block + 12, sizeof(dsi->header.dsi_reserved));
623 dsi->clientID = ntohs(dsi->header.dsi_requestID);
624
625 /* make sure we don't over-write our buffers. */
626 dsi->cmdlen = MIN(ntohl(dsi->header.dsi_len), dsi->server_quantum);
627
628 /* Receiving DSIWrite data is done in AFP function, not here */
629 if (dsi->header.dsi_data.dsi_doff) {
630 LOG(log_maxdebug, logtype_dsi, "dsi_stream_receive: write request");
631 dsi->cmdlen = dsi->header.dsi_data.dsi_doff;
632 }
633
634 if (dsi_stream_read(dsi, dsi->commands, dsi->cmdlen) != dsi->cmdlen)
635 return 0;
636
637 LOG(log_debug, logtype_dsi, "dsi_stream_receive: DSI cmdlen: %zd", dsi->cmdlen);
638
639 return block[1];
640 }
641