static void
send_error (int errnum, char *msg)
{
XDR xdr;
CLEANUP_FREE char *buf = NULL;
char lenbuf[4];
struct guestfs_message_header hdr;
struct guestfs_message_error err;
unsigned len;
/* Print the full length error message. */
fprintf (stderr, "guestfsd: error: %s\n", msg);
/* We want to truncate the error message to GUESTFS_ERROR_LEN bytes
* (not including the \0 since it is not encoded in XDR). This is
* so that the xdr_guestfs_message_error call below won't fail on
* very long error messages. We can overwrite the message since all
* callers of send_error pass a temporary buffer.
*/
if (strlen (msg) > GUESTFS_ERROR_LEN)
msg[GUESTFS_ERROR_LEN] = '\0';
buf = malloc (GUESTFS_ERROR_LEN + 200);
if (!buf)
error (EXIT_FAILURE, errno, "malloc");
xdrmem_create (&xdr, buf, GUESTFS_ERROR_LEN + 200, XDR_ENCODE);
memset (&hdr, 0, sizeof hdr);
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))
error (EXIT_FAILURE, 0, "failed to encode error message header");
/* 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_int_errno_to_string (errnum) : "");
err.error_message = (char *) msg;
if (!xdr_guestfs_message_error (&xdr, &err))
error (EXIT_FAILURE, 0, "failed to encode error message body");
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)
error (EXIT_FAILURE, 0, "xwrite failed");
if (xwrite (sock, buf, len) == -1)
error (EXIT_FAILURE, 0, "xwrite failed");
}
/* Receive a reply. */
int
guestfs___recv (guestfs_h *g, const char *fn,
guestfs_message_header *hdr,
guestfs_message_error *err,
xdrproc_t xdrp, char *ret)
{
XDR xdr;
void *buf;
uint32_t size;
int r;
again:
r = guestfs___recv_from_daemon (g, &size, &buf);
if (r == -1)
return -1;
/* This can happen if a cancellation happens right at the end
* of us sending a FileIn parameter to the daemon. Discard. The
* daemon should send us an error message next.
*/
if (size == GUESTFS_CANCEL_FLAG)
goto again;
if (size == GUESTFS_LAUNCH_FLAG) {
error (g, "%s: received unexpected launch flag from daemon when expecting reply", fn);
return -1;
}
xdrmem_create (&xdr, buf, size, XDR_DECODE);
if (!xdr_guestfs_message_header (&xdr, hdr)) {
error (g, "%s: failed to parse reply header", fn);
xdr_destroy (&xdr);
free (buf);
return -1;
}
if (hdr->status == GUESTFS_STATUS_ERROR) {
if (!xdr_guestfs_message_error (&xdr, err)) {
error (g, "%s: failed to parse reply error", fn);
xdr_destroy (&xdr);
free (buf);
return -1;
}
} else {
if (xdrp && ret && !xdrp (&xdr, ret)) {
error (g, "%s: failed to parse reply", fn);
xdr_destroy (&xdr);
free (buf);
return -1;
}
}
xdr_destroy (&xdr);
free (buf);
return 0;
}
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);
memset (&hdr, 0, sizeof hdr);
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);
}
}
