From 526e5c6559928ed98332dd27f026e8cbc95f466a Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 14 Oct 2016 13:33:08 -0500 Subject: [PATCH] nbd: Share common reply-sending code in server Rather than open-coding NBD_REP_SERVER, reuse the code we already have by adding a length parameter. Additionally, the refactoring will make adding NBD_OPT_GO in a later patch easier. Signed-off-by: Eric Blake Message-Id: <1476469998-28592-7-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini --- nbd/server.c | 52 +++++++++++++++++++++++++++------------------------- 1 file changed, 27 insertions(+), 25 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index badc2d1..0f0c68c 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -196,12 +196,15 @@ static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size) */ -static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) +/* Send a reply header, including length, but no payload. + * Return -errno on error, 0 on success. */ +static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type, + uint32_t opt, uint32_t len) { uint64_t magic; - uint32_t len; - TRACE("Reply opt=%" PRIx32 " type=%" PRIx32, type, opt); + TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32, + type, opt, len); magic = cpu_to_be64(NBD_REP_MAGIC); if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) { @@ -218,7 +221,7 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) LOG("write failed (rep type)"); return -EINVAL; } - len = cpu_to_be32(0); + len = cpu_to_be32(len); if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) { LOG("write failed (rep data length)"); return -EINVAL; @@ -226,37 +229,32 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) return 0; } +/* Send a reply header with default 0 length. + * Return -errno on error, 0 on success. */ +static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) +{ + return nbd_negotiate_send_rep_len(ioc, type, opt, 0); +} + +/* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. + * Return -errno on error, 0 on success. */ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) { - uint64_t magic; size_t name_len, desc_len; - uint32_t opt, type, len; + uint32_t len; const char *name = exp->name ? exp->name : ""; const char *desc = exp->description ? exp->description : ""; + int rc; TRACE("Advertising export name '%s' description '%s'", name, desc); name_len = strlen(name); desc_len = strlen(desc); - magic = cpu_to_be64(NBD_REP_MAGIC); - if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) { - LOG("write failed (magic)"); - return -EINVAL; - } - opt = cpu_to_be32(NBD_OPT_LIST); - if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) { - LOG("write failed (opt)"); - return -EINVAL; - } - type = cpu_to_be32(NBD_REP_SERVER); - if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) { - LOG("write failed (reply type)"); - return -EINVAL; - } - len = cpu_to_be32(name_len + desc_len + sizeof(len)); - if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) { - LOG("write failed (length)"); - return -EINVAL; + len = name_len + desc_len + sizeof(len); + rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len); + if (rc < 0) { + return rc; } + len = cpu_to_be32(name_len); if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) { LOG("write failed (name length)"); @@ -273,6 +271,8 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) return 0; } +/* Process the NBD_OPT_LIST command, with a potential series of replies. + * Return -errno on error, 0 on success. */ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) { NBDExport *exp; @@ -382,6 +382,8 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, } +/* Process all NBD_OPT_* client option commands. + * Return -errno on error, 0 on success. */ static int nbd_negotiate_options(NBDClient *client) { uint32_t flags; -- 2.7.4