/* nbdkit * Copyright (C) 2013 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * * Neither the name of Red Hat nor the names of its contributors may be * used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* example1: * * This is (almost) the most minimal nbdkit plugin possible. It * serves, readonly, from memory, a static blob of data. */ #include <config.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <nbdkit-plugin.h> /* This looks like a 100MB disk with one empty partition. */ static unsigned char bootsector[512] = { 0xfa, 0xb8, 0x00, 0x10, 0x8e, 0xd0, 0xbc, 0x00, 0xb0, 0xb8, 0x00, 0x00, 0x8e, 0xd8, 0x8e, 0xc0, 0xfb, 0xbe, 0x00, 0x7c, 0xbf, 0x00, 0x06, 0xb9, 0x00, 0x02, 0xf3, 0xa4, 0xea, 0x21, 0x06, 0x00, 0x00, 0xbe, 0xbe, 0x07, 0x38, 0x04, 0x75, 0x0b, 0x83, 0xc6, 0x10, 0x81, 0xfe, 0xfe, 0x07, 0x75, 0xf3, 0xeb, 0x16, 0xb4, 0x02, 0xb0, 0x01, 0xbb, 0x00, 0x7c, 0xb2, 0x80, 0x8a, 0x74, 0x01, 0x8b, 0x4c, 0x02, 0xcd, 0x13, 0xea, 0x00, 0x7c, 0x00, 0x00, 0xeb, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe1, 0x5b, 0x02, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x00, 0x83, 0xbc, 0x31, 0x0c, 0x80, 0x00, 0x00, 0x00, 0x01, 0x1f, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xaa }; static unsigned char data[104857600]; /* A '.load' callback is not generally required, but in this case we * need to initialize the 'data' array once when the plugin is loaded * into nbdkit. */ static void example1_load (void) { memcpy (data, bootsector, sizeof bootsector); } /* Because this plugin can only serve readonly, we can ignore the * 'readonly' parameter. */ static void * example1_open (int readonly) { /* In this trivial example we don't care about per-connection * handles (every connection serves up the same content and there is * no connection state), so we just have to return something that is * non-NULL and doesn't need to be freed. */ return data; } /* Size of the data we are going to serve. */ static int64_t example1_get_size (void *handle) { return (int64_t) sizeof (data); } /* In fact NBDKIT_THREAD_MODEL_PARALLEL would work here. However for * the benefit of people who blindly cut and paste code without * bothering to read any documentation, leave this at a safe default. */ #define THREAD_MODEL NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS /* Copy the static data at offset to the buffer. Note that nbdkit * takes care of bounds- and sanity-checking the request. */ static int example1_pread (void *handle, void *buf, uint32_t count, uint64_t offset) { memcpy (buf, data+offset, count); return 0; /* 0 = success, -1 = error */ } static struct nbdkit_plugin plugin = { .name = "example1", .version = PACKAGE_VERSION, .load = example1_load, .open = example1_open, .get_size = example1_get_size, .pread = example1_pread, }; NBDKIT_REGISTER_PLUGIN(plugin)