+ char err[GUESTFS_ERROR_LEN];
+ va_list args;
+
+ va_start (args, fs);
+ vsnprintf (err, sizeof err, fs, args);
+ va_end (args);
+
+ send_error (0, err);
+}
+
+void
+reply_with_perror_errno (int err, const char *fs, ...)
+{
+ char buf1[GUESTFS_ERROR_LEN];
+ char buf2[GUESTFS_ERROR_LEN];
+ va_list args;
+
+ va_start (args, fs);
+ vsnprintf (buf1, sizeof buf1, fs, args);
+ va_end (args);
+
+ snprintf (buf2, sizeof buf2, "%s: %s", buf1, strerror (err));
+
+ send_error (err, buf2);
+}
+
+static void
+send_error (int errnum, const char *msg)
+{
+ XDR xdr;
+ char buf[GUESTFS_ERROR_LEN + 200];
+ char lenbuf[4];
+ struct guestfs_message_header hdr;
+ struct guestfs_message_error err;
+ unsigned len;
+
+ fprintf (stderr, "guestfsd: error: %s\n", msg);
+
+ xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE);
+
+ hdr.prog = GUESTFS_PROGRAM;
+ hdr.vers = GUESTFS_PROTOCOL_VERSION;
+ hdr.direction = GUESTFS_DIRECTION_REPLY;
+ hdr.status = GUESTFS_STATUS_ERROR;
+ hdr.proc = proc_nr;
+ hdr.serial = serial;
+
+ if (!xdr_guestfs_message_header (&xdr, &hdr)) {
+ fprintf (stderr, "guestfsd: failed to encode error message header\n");
+ exit (EXIT_FAILURE);
+ }
+
+ /* These strings are not going to be freed. We just cast them
+ * to (char *) because they are defined that way in the XDR structs.
+ */
+ err.errno_string =
+ (char *) (errnum > 0 ? guestfs___errno_to_string (errnum) : "");
+ err.error_message = (char *) msg;
+
+ if (!xdr_guestfs_message_error (&xdr, &err)) {
+ fprintf (stderr, "guestfsd: failed to encode error message body\n");
+ exit (EXIT_FAILURE);
+ }
+
+ len = xdr_getpos (&xdr);
+ xdr_destroy (&xdr);
+
+ xdrmem_create (&xdr, lenbuf, 4, XDR_ENCODE);
+ xdr_u_int (&xdr, &len);
+ xdr_destroy (&xdr);
+
+ if (xwrite (sock, lenbuf, 4) == -1) {
+ fprintf (stderr, "guestfsd: xwrite failed\n");
+ exit (EXIT_FAILURE);
+ }
+ if (xwrite (sock, buf, len) == -1) {
+ fprintf (stderr, "guestfsd: xwrite failed\n");
+ exit (EXIT_FAILURE);
+ }
+}
+
+void
+reply (xdrproc_t xdrp, char *ret)
+{
+ XDR xdr;
+ char buf[GUESTFS_MESSAGE_MAX];
+ char lenbuf[4];
+ struct guestfs_message_header hdr;
+ unsigned len;
+
+ xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE);
+
+ hdr.prog = GUESTFS_PROGRAM;
+ hdr.vers = GUESTFS_PROTOCOL_VERSION;
+ hdr.direction = GUESTFS_DIRECTION_REPLY;
+ hdr.status = GUESTFS_STATUS_OK;
+ hdr.proc = proc_nr;
+ hdr.serial = serial;
+
+ if (!xdr_guestfs_message_header (&xdr, &hdr)) {
+ fprintf (stderr, "guestfsd: failed to encode reply header\n");
+ exit (EXIT_FAILURE);
+ }
+
+ if (xdrp) {
+ /* This can fail if the reply body is too large, for example
+ * if it exceeds the maximum message size. In that case
+ * we want to return an error message instead. (RHBZ#509597).
+ */
+ if (!(*xdrp) (&xdr, ret)) {
+ reply_with_error ("guestfsd: failed to encode reply body\n(maybe the reply exceeds the maximum message size in the protocol?)");
+ xdr_destroy (&xdr);
+ return;
+ }
+ }
+
+ len = xdr_getpos (&xdr);
+ xdr_destroy (&xdr);
+
+ xdrmem_create (&xdr, lenbuf, 4, XDR_ENCODE);
+ xdr_u_int (&xdr, &len);
+ xdr_destroy (&xdr);
+
+ if (xwrite (sock, lenbuf, 4) == -1) {
+ fprintf (stderr, "guestfsd: xwrite failed\n");
+ exit (EXIT_FAILURE);
+ }
+ if (xwrite (sock, buf, len) == -1) {
+ fprintf (stderr, "guestfsd: xwrite failed\n");
+ exit (EXIT_FAILURE);
+ }
+}
+
+/* Receive file chunks, repeatedly calling 'cb'. */
+int
+receive_file (receive_cb cb, void *opaque)
+{
+ guestfs_chunk chunk;
+ char lenbuf[4];
+ char *buf;
+ XDR xdr;
+ int r;
+ uint32_t len;
+
+ for (;;) {
+ if (verbose)
+ fprintf (stderr, "guestfsd: receive_file: reading length word\n");
+
+ /* Read the length word. */
+ if (xread (sock, lenbuf, 4) == -1)
+ exit (EXIT_FAILURE);
+
+ xdrmem_create (&xdr, lenbuf, 4, XDR_DECODE);
+ xdr_u_int (&xdr, &len);
+ xdr_destroy (&xdr);
+
+ if (len == GUESTFS_CANCEL_FLAG)
+ continue; /* Just ignore it. */
+
+ if (len > GUESTFS_MESSAGE_MAX) {
+ fprintf (stderr, "guestfsd: incoming message is too long (%u bytes)\n",
+ len);
+ exit (EXIT_FAILURE);
+ }
+
+ buf = malloc (len);
+ if (!buf) {
+ perror ("malloc");
+ return -1;
+ }
+
+ if (xread (sock, buf, len) == -1)
+ exit (EXIT_FAILURE);
+
+ xdrmem_create (&xdr, buf, len, XDR_DECODE);
+ memset (&chunk, 0, sizeof chunk);
+ if (!xdr_guestfs_chunk (&xdr, &chunk)) {
+ xdr_destroy (&xdr);
+ free (buf);
+ return -1;
+ }
+ xdr_destroy (&xdr);
+ free (buf);
+
+ if (verbose)
+ fprintf (stderr,
+ "guestfsd: receive_file: got chunk: cancel = 0x%x, len = %d, buf = %p\n",
+ chunk.cancel, chunk.data.data_len, chunk.data.data_val);
+
+ if (chunk.cancel != 0 && chunk.cancel != 1) {
+ fprintf (stderr,
+ "guestfsd: receive_file: chunk.cancel != [0|1] ... "
+ "continuing even though we have probably lost synchronization with the library\n");
+ return -1;
+ }
+
+ if (chunk.cancel) {
+ if (verbose)
+ fprintf (stderr,
+ "guestfsd: receive_file: received cancellation from library\n");
+ xdr_free ((xdrproc_t) xdr_guestfs_chunk, (char *) &chunk);
+ return -2;
+ }
+ if (chunk.data.data_len == 0) {
+ if (verbose)
+ fprintf (stderr,
+ "guestfsd: receive_file: end of file, leaving function\n");
+ xdr_free ((xdrproc_t) xdr_guestfs_chunk, (char *) &chunk);
+ return 0; /* end of file */
+ }
+
+ /* Note that the callback can generate progress messages. */
+ if (cb)
+ r = cb (opaque, chunk.data.data_val, chunk.data.data_len);
+ else
+ r = 0;
+
+ xdr_free ((xdrproc_t) xdr_guestfs_chunk, (char *) &chunk);
+ if (r == -1) { /* write error */
+ if (verbose)
+ fprintf (stderr, "guestfsd: receive_file: write error\n");
+ return -1;
+ }
+ }
+}
+
+/* Send a cancellation flag back to the library. */
+int
+cancel_receive (void)
+{
+ XDR xdr;
+ char fbuf[4];
+ uint32_t flag = GUESTFS_CANCEL_FLAG;
+
+ xdrmem_create (&xdr, fbuf, sizeof fbuf, XDR_ENCODE);
+ xdr_u_int (&xdr, &flag);
+ xdr_destroy (&xdr);
+
+ if (xwrite (sock, fbuf, sizeof fbuf) == -1) {
+ perror ("write to socket");
+ return -1;
+ }
+
+ /* Keep receiving chunks and discarding, until library sees cancel. */
+ return receive_file (NULL, NULL);
+}
+
+static int check_for_library_cancellation (void);
+static int send_chunk (const guestfs_chunk *);
+
+/* Also check if the library sends us a cancellation message. */
+int
+send_file_write (const void *buf, int len)
+{
+ guestfs_chunk chunk;
+ int cancel;
+
+ if (len > GUESTFS_MAX_CHUNK_SIZE) {
+ fprintf (stderr, "guestfsd: send_file_write: len (%d) > GUESTFS_MAX_CHUNK_SIZE (%d)\n",
+ len, GUESTFS_MAX_CHUNK_SIZE);
+ return -1;
+ }
+
+ cancel = check_for_library_cancellation ();
+
+ if (cancel) {
+ chunk.cancel = 1;
+ chunk.data.data_len = 0;
+ chunk.data.data_val = NULL;
+ } else {
+ chunk.cancel = 0;
+ chunk.data.data_len = len;
+ chunk.data.data_val = (char *) buf;
+ }