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>
diff --git a/block/nbd.c b/block/nbd.c
index a1ec123..5e9d6cb 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -33,6 +33,8 @@
#include <sys/types.h>
#include <unistd.h>
+#define EN_OPTSTR ":exportname="
+
typedef struct BDRVNBDState {
int sock;
off_t size;
@@ -42,55 +44,83 @@
static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
{
BDRVNBDState *s = bs->opaque;
+ uint32_t nbdflags;
+
+ char *file;
+ char *name;
const char *host;
const char *unixpath;
int sock;
off_t size;
size_t blocksize;
int ret;
+ int err = -EINVAL;
- if (!strstart(filename, "nbd:", &host))
- return -EINVAL;
+ file = qemu_strdup(filename);
+
+ name = strstr(file, EN_OPTSTR);
+ if (name) {
+ if (name[strlen(EN_OPTSTR)] == 0) {
+ goto out;
+ }
+ name[0] = 0;
+ name += strlen(EN_OPTSTR);
+ }
+
+ if (!strstart(file, "nbd:", &host)) {
+ goto out;
+ }
if (strstart(host, "unix:", &unixpath)) {
- if (unixpath[0] != '/')
- return -EINVAL;
+ if (unixpath[0] != '/') {
+ goto out;
+ }
sock = unix_socket_outgoing(unixpath);
} else {
- uint16_t port;
+ uint16_t port = NBD_DEFAULT_PORT;
char *p, *r;
char hostname[128];
pstrcpy(hostname, 128, host);
p = strchr(hostname, ':');
- if (p == NULL)
- return -EINVAL;
+ if (p != NULL) {
+ *p = '\0';
+ p++;
- *p = '\0';
- p++;
+ port = strtol(p, &r, 0);
+ if (r == p) {
+ goto out;
+ }
+ } else if (name == NULL) {
+ goto out;
+ }
- port = strtol(p, &r, 0);
- if (r == p)
- return -EINVAL;
sock = tcp_socket_outgoing(hostname, port);
}
- if (sock == -1)
- return -errno;
+ if (sock == -1) {
+ err = -errno;
+ goto out;
+ }
- ret = nbd_receive_negotiate(sock, &size, &blocksize);
- if (ret == -1)
- return -errno;
+ ret = nbd_receive_negotiate(sock, name, &nbdflags, &size, &blocksize);
+ if (ret == -1) {
+ err = -errno;
+ goto out;
+ }
s->sock = sock;
s->size = size;
s->blocksize = blocksize;
+ err = 0;
- return 0;
+out:
+ qemu_free(file);
+ return err;
}
static int nbd_read(BlockDriverState *bs, int64_t sector_num,
diff --git a/nbd.c b/nbd.c
index a9f295f..30dec8d 100644
--- a/nbd.c
+++ b/nbd.c
@@ -62,6 +62,8 @@
#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
#define NBD_DISCONNECT _IO(0xab, 8)
+#define NBD_OPT_EXPORT_NAME (1 << 0)
+
/* That's all folks */
#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
@@ -296,22 +298,27 @@
return 0;
}
-int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
+int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
+ off_t *size, size_t *blocksize)
{
- char buf[8 + 8 + 8 + 128];
- uint64_t magic;
+ char buf[256];
+ uint64_t magic, s;
+ uint16_t tmp;
TRACE("Receiving negotation.");
- if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ if (read_sync(csock, buf, 8) != 8) {
LOG("read failed");
errno = EINVAL;
return -1;
}
- magic = be64_to_cpup((uint64_t*)(buf + 8));
- *size = be64_to_cpup((uint64_t*)(buf + 16));
- *blocksize = 1024;
+ buf[8] = '\0';
+ if (strlen(buf) == 0) {
+ LOG("server connection closed");
+ errno = EINVAL;
+ return -1;
+ }
TRACE("Magic is %c%c%c%c%c%c%c%c",
qemu_isprint(buf[0]) ? buf[0] : '.',
@@ -322,8 +329,6 @@
qemu_isprint(buf[5]) ? buf[5] : '.',
qemu_isprint(buf[6]) ? buf[6] : '.',
qemu_isprint(buf[7]) ? buf[7] : '.');
- TRACE("Magic is 0x%" PRIx64, magic);
- TRACE("Size is %" PRIu64, *size);
if (memcmp(buf, "NBDMAGIC", 8) != 0) {
LOG("Invalid magic received");
@@ -331,10 +336,99 @@
return -1;
}
- TRACE("Checking magic");
+ if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
+ LOG("read failed");
+ errno = EINVAL;
+ return -1;
+ }
+ magic = be64_to_cpu(magic);
+ TRACE("Magic is 0x%" PRIx64, magic);
- if (magic != 0x00420281861253LL) {
- LOG("Bad magic received");
+ if (name) {
+ uint32_t reserved = 0;
+ uint32_t opt;
+ uint32_t namesize;
+
+ TRACE("Checking magic (opts_magic)");
+ if (magic != 0x49484156454F5054LL) {
+ LOG("Bad magic received");
+ errno = EINVAL;
+ return -1;
+ }
+ if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+ LOG("flags read failed");
+ errno = EINVAL;
+ return -1;
+ }
+ *flags = be16_to_cpu(tmp) << 16;
+ /* reserved for future use */
+ if (write_sync(csock, &reserved, sizeof(reserved)) !=
+ sizeof(reserved)) {
+ LOG("write failed (reserved)");
+ errno = EINVAL;
+ return -1;
+ }
+ /* write the export name */
+ magic = cpu_to_be64(magic);
+ if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
+ LOG("write failed (magic)");
+ errno = EINVAL;
+ return -1;
+ }
+ opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
+ if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
+ LOG("write failed (opt)");
+ errno = EINVAL;
+ return -1;
+ }
+ namesize = cpu_to_be32(strlen(name));
+ if (write_sync(csock, &namesize, sizeof(namesize)) !=
+ sizeof(namesize)) {
+ LOG("write failed (namesize)");
+ errno = EINVAL;
+ return -1;
+ }
+ if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) {
+ LOG("write failed (name)");
+ errno = EINVAL;
+ return -1;
+ }
+ } else {
+ TRACE("Checking magic (cli_magic)");
+
+ if (magic != 0x00420281861253LL) {
+ LOG("Bad magic received");
+ errno = EINVAL;
+ return -1;
+ }
+ }
+
+ if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) {
+ LOG("read failed");
+ errno = EINVAL;
+ return -1;
+ }
+ *size = be64_to_cpu(s);
+ *blocksize = 1024;
+ TRACE("Size is %" PRIu64, *size);
+
+ if (!name) {
+ if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) {
+ LOG("read failed (flags)");
+ errno = EINVAL;
+ return -1;
+ }
+ *flags = be32_to_cpup(flags);
+ } else {
+ if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+ LOG("read failed (tmp)");
+ errno = EINVAL;
+ return -1;
+ }
+ *flags |= be32_to_cpu(tmp);
+ }
+ if (read_sync(csock, &buf, 124) != 124) {
+ LOG("read failed (buf)");
errno = EINVAL;
return -1;
}
diff --git a/nbd.h b/nbd.h
index 5a1fbdf..8ff65a1 100644
--- a/nbd.h
+++ b/nbd.h
@@ -42,6 +42,8 @@
NBD_CMD_DISC = 2
};
+#define NBD_DEFAULT_PORT 10809
+
size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
int tcp_socket_outgoing(const char *address, uint16_t port);
int tcp_socket_incoming(const char *address, uint16_t port);
@@ -49,7 +51,8 @@
int unix_socket_incoming(const char *path);
int nbd_negotiate(int csock, off_t size);
-int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
+int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
+ off_t *size, size_t *blocksize);
int nbd_init(int fd, int csock, off_t size, size_t blocksize);
int nbd_send_request(int csock, struct nbd_request *request);
int nbd_receive_reply(int csock, struct nbd_reply *reply);
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 55a966f..d7d760f 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -620,6 +620,13 @@
qemu linux2.img -hdb nbd:unix:/tmp/my_socket
@end example
+If the nbd-server uses named exports (since NBD 2.9.18), you must use the
+"exportname" option:
+@example
+qemu -cdrom nbd:localhost:exportname=debian-500-ppc-netinst
+qemu -cdrom nbd:localhost:exportname=openSUSE-11.1-ppc-netinst
+@end example
+
@node pcsys_network
@section Network emulation
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 4e607cf..41e5c5d 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -230,6 +230,7 @@
int nb_fds = 0;
int max_fd;
int persistent = 0;
+ uint32_t nbdflags;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@@ -398,7 +399,8 @@
goto out;
}
- ret = nbd_receive_negotiate(sock, &size, &blocksize);
+ ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
+ &size, &blocksize);
if (ret == -1) {
ret = 1;
goto out;
