4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * * Neither the name of Red Hat nor the names of its contributors may be
16 * used to endorse or promote products derived from this software without
17 * specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
22 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
26 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
27 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
29 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 #include <nbdkit-filter.h>
46 static enum CacheMode
{
53 nocache_config (nbdkit_next_config
*next
, nbdkit_backend
*nxdata
,
54 const char *key
, const char *value
)
56 if (strcmp (key
, "cachemode") == 0) {
57 if (strcmp (value
, "emulate") == 0)
59 else if (strcmp (value
, "nop") == 0 ||
60 strcmp (value
, "no-op") == 0)
62 else if (strcmp (value
, "none") != 0) {
63 nbdkit_error ("unknown cachemode '%s'", value
);
68 return next (nxdata
, key
, value
);
71 #define nocache_config_help \
72 "cachemode=<MODE> Either 'none' (default), 'emulate', or 'nop'.\n" \
74 /* Advertise desired FLAG_SEND_CACHE mode. */
76 nocache_can_cache (nbdkit_next
*next
,
81 return NBDKIT_CACHE_NONE
;
83 return NBDKIT_CACHE_EMULATE
;
85 return NBDKIT_CACHE_NATIVE
;
91 nocache_cache (nbdkit_next
*next
,
92 void *handle
, uint32_t count
, uint64_t offs
, uint32_t flags
,
95 assert (cachemode
== NOP
);
101 static struct nbdkit_filter filter
= {
103 .longname
= "nbdkit nocache filter",
104 .config
= nocache_config
,
105 .config_help
= nocache_config_help
,
106 .can_cache
= nocache_can_cache
,
107 .cache
= nocache_cache
,
110 NBDKIT_REGISTER_FILTER (filter
)