1 /* libguestfs - the guestfsd daemon
2 * Copyright (C) 2009 Red Hat Inc.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include <sys/param.h> /* defines MIN */
29 #include <rpc/types.h>
33 #include "../src/guestfs_protocol.h"
35 /* The message currently being processed. */
39 /* The daemon communications socket. */
49 struct guestfs_message_header hdr;
55 /* Most common errors are leaked memory and leaked file descriptors,
56 * so run this between each command:
59 system ("ls -l /proc/self/fd");
62 /* Read the length word. */
63 xread (sock, lenbuf, 4);
64 xdrmem_create (&xdr, lenbuf, 4, XDR_DECODE);
65 xdr_uint32_t (&xdr, &len);
68 if (len > GUESTFS_MESSAGE_MAX) {
69 fprintf (stderr, "guestfsd: incoming message is too long (%u bytes)\n",
76 reply_with_perror ("malloc");
80 xread (sock, buf, len);
85 for (i = 0; i < len; i += 16) {
87 for (j = i; j < MIN (i+16, len); ++j)
88 printf ("%02x ", (unsigned char) buf[j]);
92 for (j = i; j < MIN (i+16, len); ++j)
94 printf ("%c", buf[j]);
103 /* Decode the message header. */
104 xdrmem_create (&xdr, buf, len, XDR_DECODE);
105 if (!xdr_guestfs_message_header (&xdr, &hdr)) {
106 fprintf (stderr, "guestfsd: could not decode message header\n");
110 /* Check the version etc. */
111 if (hdr.prog != GUESTFS_PROGRAM) {
112 reply_with_error ("wrong program (%d)", hdr.prog);
115 if (hdr.vers != GUESTFS_PROTOCOL_VERSION) {
116 reply_with_error ("wrong protocol version (%d)", hdr.vers);
119 if (hdr.direction != GUESTFS_DIRECTION_CALL) {
120 reply_with_error ("unexpected message direction (%d)", hdr.direction);
123 if (hdr.status != GUESTFS_STATUS_OK) {
124 reply_with_error ("unexpected message status (%d)", hdr.status);
128 /* Now start to process this message. */
131 dispatch_incoming_message (&xdr);
132 /* Note that dispatch_incoming_message will also send a reply. */
140 static void send_error (const char *msg);
143 reply_with_error (const char *fs, ...)
145 char err[GUESTFS_ERROR_LEN];
149 vsnprintf (err, sizeof err, fs, args);
156 reply_with_perror (const char *fs, ...)
158 char buf1[GUESTFS_ERROR_LEN];
159 char buf2[GUESTFS_ERROR_LEN];
164 vsnprintf (buf1, sizeof buf1, fs, args);
167 snprintf (buf2, sizeof buf2, "%s: %s", buf1, strerror (err));
173 send_error (const char *msg)
176 char buf[GUESTFS_ERROR_LEN + 200];
178 struct guestfs_message_header hdr;
179 struct guestfs_message_error err;
182 fprintf (stderr, "guestfsd: error: %s\n", msg);
184 xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE);
186 hdr.prog = GUESTFS_PROGRAM;
187 hdr.vers = GUESTFS_PROTOCOL_VERSION;
188 hdr.direction = GUESTFS_DIRECTION_REPLY;
189 hdr.status = GUESTFS_STATUS_ERROR;
193 if (!xdr_guestfs_message_header (&xdr, &hdr)) {
194 fprintf (stderr, "guestfsd: failed to encode error message header\n");
198 err.error_message = (char *) msg;
200 if (!xdr_guestfs_message_error (&xdr, &err)) {
201 fprintf (stderr, "guestfsd: failed to encode error message body\n");
205 len = xdr_getpos (&xdr);
208 xdrmem_create (&xdr, lenbuf, 4, XDR_ENCODE);
209 xdr_uint32_t (&xdr, &len);
212 (void) xwrite (sock, lenbuf, 4);
213 (void) xwrite (sock, buf, len);
217 reply (xdrproc_t xdrp, char *ret)
220 char buf[GUESTFS_MESSAGE_MAX];
222 struct guestfs_message_header hdr;
225 xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE);
227 hdr.prog = GUESTFS_PROGRAM;
228 hdr.vers = GUESTFS_PROTOCOL_VERSION;
229 hdr.direction = GUESTFS_DIRECTION_REPLY;
230 hdr.status = GUESTFS_STATUS_OK;
234 if (!xdr_guestfs_message_header (&xdr, &hdr)) {
235 fprintf (stderr, "guestfsd: failed to encode reply header\n");
240 if (!(*xdrp) (&xdr, ret)) {
241 fprintf (stderr, "guestfsd: failed to encode reply body\n");
246 len = xdr_getpos (&xdr);
249 xdrmem_create (&xdr, lenbuf, 4, XDR_ENCODE);
250 xdr_uint32_t (&xdr, &len);
253 (void) xwrite (sock, lenbuf, 4);
254 (void) xwrite (sock, buf, len);
257 /* Receive file chunks, repeatedly calling 'cb'. */
259 receive_file (receive_cb cb, void *opaque)
269 /* Read the length word. */
270 xread (sock, lenbuf, 4);
271 xdrmem_create (&xdr, lenbuf, 4, XDR_DECODE);
272 xdr_uint32_t (&xdr, &len);
275 if (len == GUESTFS_CANCEL_FLAG)
276 continue; /* Just ignore it. */
278 if (len > GUESTFS_MESSAGE_MAX) {
279 fprintf (stderr, "guestfsd: incoming message is too long (%u bytes)\n",
290 xread (sock, buf, len);
292 xdrmem_create (&xdr, buf, len, XDR_DECODE);
293 memset (&chunk, 0, sizeof chunk);
294 if (!xdr_guestfs_chunk (&xdr, &chunk)) {
303 printf ("receive_file: got chunk: cancel = %d, len = %d, buf = %p\n",
304 chunk.cancel, chunk.data.data_len, chunk.data.data_val);
307 fprintf (stderr, "receive_file: received cancellation from library\n");
308 xdr_free ((xdrproc_t) xdr_guestfs_chunk, (char *) &chunk);
311 if (chunk.data.data_len == 0) {
312 xdr_free ((xdrproc_t) xdr_guestfs_chunk, (char *) &chunk);
313 return 0; /* end of file */
317 r = cb (opaque, chunk.data.data_val, chunk.data.data_len);
321 xdr_free ((xdrproc_t) xdr_guestfs_chunk, (char *) &chunk);
322 if (r == -1) /* write error */
327 /* Send a cancellation flag back to the library. */
329 cancel_receive (void)
333 uint32_t flag = GUESTFS_CANCEL_FLAG;
335 xdrmem_create (&xdr, fbuf, sizeof fbuf, XDR_ENCODE);
336 xdr_uint32_t (&xdr, &flag);
339 if (xwrite (sock, fbuf, sizeof fbuf) == -1) {
340 perror ("write to socket");
344 /* Keep receiving chunks and discarding, until library sees cancel. */
345 (void) receive_file (NULL, NULL);
348 static int check_for_library_cancellation (void);
349 static int send_chunk (const guestfs_chunk *);
351 /* Also check if the library sends us a cancellation message. */
353 send_file_write (const void *buf, int len)
358 if (len > GUESTFS_MAX_CHUNK_SIZE) {
359 fprintf (stderr, "send_file_write: len (%d) > GUESTFS_MAX_CHUNK_SIZE (%d)\n",
360 len, GUESTFS_MAX_CHUNK_SIZE);
364 cancel = check_for_library_cancellation ();
368 chunk.data.data_len = 0;
369 chunk.data.data_val = NULL;
372 chunk.data.data_len = len;
373 chunk.data.data_val = (char *) buf;
376 if (send_chunk (&chunk) == -1)
379 if (cancel) return -2;
384 check_for_library_cancellation (void)
394 FD_SET (sock, &rset);
397 r = select (sock+1, &rset, NULL, NULL, &tv);
405 /* Read the message from the daemon. */
406 r = xread (sock, buf, sizeof buf);
412 xdrmem_create (&xdr, buf, sizeof buf, XDR_DECODE);
413 xdr_uint32_t (&xdr, &flag);
416 if (flag != GUESTFS_CANCEL_FLAG) {
417 fprintf (stderr, "check_for_library_cancellation: read 0x%x from library, expected 0x%x\n",
418 flag, GUESTFS_CANCEL_FLAG);
426 send_file_end (int cancel)
430 chunk.cancel = cancel;
431 chunk.data.data_len = 0;
432 chunk.data.data_val = NULL;
437 send_chunk (const guestfs_chunk *chunk)
439 char buf[GUESTFS_MAX_CHUNK_SIZE + 48];
444 xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE);
445 if (!xdr_guestfs_chunk (&xdr, (guestfs_chunk *) chunk)) {
446 fprintf (stderr, "send_chunk: failed to encode chunk\n");
451 len = xdr_getpos (&xdr);
454 xdrmem_create (&xdr, lenbuf, 4, XDR_ENCODE);
455 xdr_uint32_t (&xdr, &len);
458 (void) xwrite (sock, lenbuf, 4);
459 (void) xwrite (sock, buf, len);