Am 24.08.2010 03:04, schrieb Laurent Vivier:
> 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 <laur...@vivier.eu>
> ---
> block/nbd.c | 57 +++++++++++++++++++--------
> nbd.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++------
> nbd.h | 5 ++-
> qemu-doc.texi | 7 +++
> qemu-nbd.c | 2 +-
> 5 files changed, 158 insertions(+), 32 deletions(-)
>
> diff --git a/block/nbd.c b/block/nbd.c
> index a1ec123..ee22b47 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -42,55 +42,78 @@ typedef struct BDRVNBDState {
> static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
> {
> BDRVNBDState *s = bs->opaque;
> +
> + #define EN_OPTSTR ":exportname="
Hm, this makes EN_OPTSTR look like a local variable, but it's actually a
macro which is valid after the end of the function. So maybe move it out?
> + char *file;
> + char *name;
> const char *host;
> const char *unixpath;
> int sock;
> off_t size;
> size_t blocksize;
> int ret;
> + int err = -EINVAL;
> +
> + file = qemu_strdup(filename);
>
> - if (!strstart(filename, "nbd:", &host))
> - return -EINVAL;
> + name = strstr(file, EN_OPTSTR);
> + if (name) {
> + if (name[sizeof(EN_OPTSTR) - 1] == 0)
> + goto out;
Please add braces here and throughout the patch (see CODING_STYLE)
Maybe using strlen(EN_OPTSTR) would be clearer? At first I missed the
fact that sizeof includes the null byte, but maybe it's just me.
> + name[0] = 0;
> + name += sizeof(EN_OPTSTR) - 1;
> + }
> +
> + if (!strstart(file, "nbd:", &host))
> + goto out;
>
> if (strstart(host, "unix:", &unixpath)) {
>
> if (unixpath[0] != '/')
> - return -EINVAL;
> + 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;
Wrong indentation level (and missing braces again)
>
> - 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, &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..755613a 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 +298,26 @@ int nbd_negotiate(int csock, off_t size)
> return 0;
> }
>
> -int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
> +int nbd_receive_negotiate(int csock, const char *name,
> + off_t *size, size_t *blocksize)
> {
> - char buf[8 + 8 + 8 + 128];
> - uint64_t magic;
> + char buf[256] = "\0\0\0\0\0\0\0\0\0";
> + uint64_t magic, s;
> + uint16_t tmp;
> + uint32_t flags;
Hm, where are the flags actually used? There are a few places where they
are assigned, but I can't see any use.
>
> 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;
> }
I think this makes it easy to miss that you rely on getting null
termination by the initialisation of buf. Why not do the obvious thing
and just do a buf[8] = '\0' after the read?
> -
> - magic = be64_to_cpup((uint64_t*)(buf + 8));
> - *size = be64_to_cpup((uint64_t*)(buf + 16));
> - *blocksize = 1024;
> + 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 +328,6 @@ int nbd_receive_negotiate(int csock, off_t *size, size_t
> *blocksize)
> 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 +335,99 @@ int nbd_receive_negotiate(int csock, off_t *size,
> size_t *blocksize)
> 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 = be64_to_cpu(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..17be0fa 100644
> --- a/nbd.h
> +++ b/nbd.h
> @@ -42,6 +42,8 @@ enum {
> 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_outgoing(const char *path);
> 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,
> + 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..ca5bf53 100644
> --- a/qemu-doc.texi
> +++ b/qemu-doc.texi
> @@ -620,6 +620,13 @@ qemu linux1.img -hdb nbd:unix:/tmp/my_socket
> 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
Please remove the space before the comma.
I don't have a new enough ndbserver to test if it actually works (and I
also haven't checked the spec for the new parts), so I'll have to trust
your tests there.
Kevin
