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nbd: Introduce NBD named exports.
This patch allows to connect Qemu using NBD protocol to an nbd-server
using named exports.
For instance, if on the host "isoserver", in /etc/nbd-server/config, you have:
[generic]
[debian-500-ppc-netinst]
exportname = /ISO/debian-500-powerpc-netinst.iso
[Fedora-10-ppc-netinst]
exportname = /ISO/Fedora-10-ppc-netinst.iso
You can connect to it, using:
qemu -cdrom nbd:isoserver:exportname=debian-500-ppc-netinst
qemu -cdrom nbd:isoserver:exportname=Fedora-10-ppc-netinst
NOTE: you need at least nbd-server 2.9.18
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Laurent Vivier
Kevin Wolf
parent
2aa326be0d
commit
1d45f8b542
66
block/nbd.c
66
block/nbd.c
@ -33,6 +33,8 @@
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#include <sys/types.h>
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#include <unistd.h>
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#define EN_OPTSTR ":exportname="
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typedef struct BDRVNBDState {
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int sock;
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off_t size;
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@ -42,55 +44,83 @@ typedef struct BDRVNBDState {
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static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
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{
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BDRVNBDState *s = bs->opaque;
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uint32_t nbdflags;
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char *file;
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char *name;
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const char *host;
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const char *unixpath;
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int sock;
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off_t size;
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size_t blocksize;
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int ret;
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int err = -EINVAL;
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if (!strstart(filename, "nbd:", &host))
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return -EINVAL;
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file = qemu_strdup(filename);
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name = strstr(file, EN_OPTSTR);
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if (name) {
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if (name[strlen(EN_OPTSTR)] == 0) {
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goto out;
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}
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name[0] = 0;
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name += strlen(EN_OPTSTR);
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}
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if (!strstart(file, "nbd:", &host)) {
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goto out;
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}
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if (strstart(host, "unix:", &unixpath)) {
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if (unixpath[0] != '/')
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return -EINVAL;
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if (unixpath[0] != '/') {
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goto out;
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}
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sock = unix_socket_outgoing(unixpath);
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} else {
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uint16_t port;
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uint16_t port = NBD_DEFAULT_PORT;
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char *p, *r;
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char hostname[128];
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pstrcpy(hostname, 128, host);
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p = strchr(hostname, ':');
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if (p == NULL)
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return -EINVAL;
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if (p != NULL) {
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*p = '\0';
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p++;
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*p = '\0';
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p++;
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port = strtol(p, &r, 0);
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if (r == p) {
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goto out;
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}
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} else if (name == NULL) {
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goto out;
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}
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port = strtol(p, &r, 0);
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if (r == p)
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return -EINVAL;
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sock = tcp_socket_outgoing(hostname, port);
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}
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if (sock == -1)
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return -errno;
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if (sock == -1) {
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err = -errno;
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goto out;
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}
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ret = nbd_receive_negotiate(sock, &size, &blocksize);
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if (ret == -1)
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return -errno;
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ret = nbd_receive_negotiate(sock, name, &nbdflags, &size, &blocksize);
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if (ret == -1) {
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err = -errno;
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goto out;
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}
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s->sock = sock;
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s->size = size;
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s->blocksize = blocksize;
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err = 0;
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return 0;
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out:
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qemu_free(file);
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return err;
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}
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static int nbd_read(BlockDriverState *bs, int64_t sector_num,
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118
nbd.c
118
nbd.c
@ -62,6 +62,8 @@
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#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
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#define NBD_DISCONNECT _IO(0xab, 8)
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#define NBD_OPT_EXPORT_NAME (1 << 0)
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/* That's all folks */
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#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
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@ -296,22 +298,27 @@ int nbd_negotiate(int csock, off_t size)
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return 0;
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}
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int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
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int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
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off_t *size, size_t *blocksize)
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{
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char buf[8 + 8 + 8 + 128];
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uint64_t magic;
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char buf[256];
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uint64_t magic, s;
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uint16_t tmp;
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TRACE("Receiving negotation.");
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if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
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if (read_sync(csock, buf, 8) != 8) {
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LOG("read failed");
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errno = EINVAL;
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return -1;
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}
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magic = be64_to_cpup((uint64_t*)(buf + 8));
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*size = be64_to_cpup((uint64_t*)(buf + 16));
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*blocksize = 1024;
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buf[8] = '\0';
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if (strlen(buf) == 0) {
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LOG("server connection closed");
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errno = EINVAL;
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return -1;
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}
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TRACE("Magic is %c%c%c%c%c%c%c%c",
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qemu_isprint(buf[0]) ? buf[0] : '.',
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@ -322,8 +329,6 @@ int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
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qemu_isprint(buf[5]) ? buf[5] : '.',
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qemu_isprint(buf[6]) ? buf[6] : '.',
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qemu_isprint(buf[7]) ? buf[7] : '.');
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TRACE("Magic is 0x%" PRIx64, magic);
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TRACE("Size is %" PRIu64, *size);
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if (memcmp(buf, "NBDMAGIC", 8) != 0) {
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LOG("Invalid magic received");
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@ -331,10 +336,99 @@ int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
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return -1;
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}
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TRACE("Checking magic");
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if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
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LOG("read failed");
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errno = EINVAL;
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return -1;
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}
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magic = be64_to_cpu(magic);
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TRACE("Magic is 0x%" PRIx64, magic);
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if (magic != 0x00420281861253LL) {
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LOG("Bad magic received");
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if (name) {
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uint32_t reserved = 0;
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uint32_t opt;
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uint32_t namesize;
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TRACE("Checking magic (opts_magic)");
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if (magic != 0x49484156454F5054LL) {
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LOG("Bad magic received");
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errno = EINVAL;
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return -1;
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}
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if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
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LOG("flags read failed");
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errno = EINVAL;
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return -1;
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}
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*flags = be16_to_cpu(tmp) << 16;
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/* reserved for future use */
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if (write_sync(csock, &reserved, sizeof(reserved)) !=
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sizeof(reserved)) {
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LOG("write failed (reserved)");
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errno = EINVAL;
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return -1;
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}
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/* write the export name */
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magic = cpu_to_be64(magic);
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if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
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LOG("write failed (magic)");
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errno = EINVAL;
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return -1;
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}
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opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
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if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
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LOG("write failed (opt)");
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errno = EINVAL;
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return -1;
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}
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namesize = cpu_to_be32(strlen(name));
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if (write_sync(csock, &namesize, sizeof(namesize)) !=
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sizeof(namesize)) {
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LOG("write failed (namesize)");
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errno = EINVAL;
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return -1;
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}
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if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
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LOG("write failed (name)");
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errno = EINVAL;
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return -1;
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}
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} else {
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TRACE("Checking magic (cli_magic)");
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if (magic != 0x00420281861253LL) {
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LOG("Bad magic received");
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errno = EINVAL;
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return -1;
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}
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}
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if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
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LOG("read failed");
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errno = EINVAL;
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return -1;
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}
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*size = be64_to_cpu(s);
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*blocksize = 1024;
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TRACE("Size is %" PRIu64, *size);
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if (!name) {
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if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
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LOG("read failed (flags)");
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errno = EINVAL;
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return -1;
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}
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*flags = be32_to_cpup(flags);
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} else {
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if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
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LOG("read failed (tmp)");
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errno = EINVAL;
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return -1;
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}
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*flags |= be32_to_cpu(tmp);
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}
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if (read_sync(csock, &buf, 124) != 124) {
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LOG("read failed (buf)");
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errno = EINVAL;
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return -1;
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}
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5
nbd.h
5
nbd.h
@ -42,6 +42,8 @@ enum {
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NBD_CMD_DISC = 2
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};
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#define NBD_DEFAULT_PORT 10809
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size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
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int tcp_socket_outgoing(const char *address, uint16_t port);
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int tcp_socket_incoming(const char *address, uint16_t port);
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@ -49,7 +51,8 @@ int unix_socket_outgoing(const char *path);
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int unix_socket_incoming(const char *path);
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int nbd_negotiate(int csock, off_t size);
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int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
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int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
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off_t *size, size_t *blocksize);
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int nbd_init(int fd, int csock, off_t size, size_t blocksize);
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int nbd_send_request(int csock, struct nbd_request *request);
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int nbd_receive_reply(int csock, struct nbd_reply *reply);
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@ -620,6 +620,13 @@ qemu linux1.img -hdb nbd:unix:/tmp/my_socket
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qemu linux2.img -hdb nbd:unix:/tmp/my_socket
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@end example
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If the nbd-server uses named exports (since NBD 2.9.18), you must use the
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"exportname" option:
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@example
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qemu -cdrom nbd:localhost:exportname=debian-500-ppc-netinst
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qemu -cdrom nbd:localhost:exportname=openSUSE-11.1-ppc-netinst
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@end example
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@node pcsys_network
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@section Network emulation
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@ -230,6 +230,7 @@ int main(int argc, char **argv)
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int nb_fds = 0;
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int max_fd;
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int persistent = 0;
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uint32_t nbdflags;
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while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
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switch (ch) {
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@ -398,7 +399,8 @@ int main(int argc, char **argv)
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goto out;
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}
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ret = nbd_receive_negotiate(sock, &size, &blocksize);
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ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
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&size, &blocksize);
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if (ret == -1) {
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ret = 1;
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goto out;
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