9:49 a.m.
Stating that our magic is the C string "NBDMAGIC" is ambiguous, since
not all the world uses ASCII. Switch to something that is
wire-compatible even if compiled in an EBCDIC environment.
Signed-off-by: Eric Blake <eblake(a)redhat.com>
---
common/protocol/nbd-protocol.h | 9 +++++----
server/protocol-handshake-newstyle.c | 2 +-
server/protocol-handshake-oldstyle.c | 2 +-
plugins/nbd/nbd-standalone.c | 2 +-
tests/test-layers.c | 2 +-
5 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/common/protocol/nbd-protocol.h b/common/protocol/nbd-protocol.h
index a7a70116..9bf7171e 100644
--- a/common/protocol/nbd-protocol.h
+++ b/common/protocol/nbd-protocol.h
@@ -50,7 +50,7 @@
/* Old-style handshake. */
struct nbd_old_handshake {
- char nbdmagic[8]; /* "NBDMAGIC" */
+ uint64_t nbdmagic; /* NBD_MAGIC */
uint64_t version; /* NBD_OLD_VERSION */
uint64_t exportsize;
uint16_t gflags; /* global flags */
@@ -58,20 +58,21 @@ struct nbd_old_handshake {
char zeroes[124]; /* must be sent as zero bytes */
} NBD_ATTRIBUTE_PACKED;
+#define NBD_MAGIC UINT64_C(0x4e42444d41474943) /* ASCII "NBDMAGIC" */
#define NBD_OLD_VERSION UINT64_C(0x420281861253)
/* New-style handshake. */
struct nbd_new_handshake {
- char nbdmagic[8]; /* "NBDMAGIC" */
+ uint64_t nbdmagic; /* NBD_MAGIC */
uint64_t version; /* NBD_NEW_VERSION */
uint16_t gflags; /* global flags */
} NBD_ATTRIBUTE_PACKED;
-#define NBD_NEW_VERSION UINT64_C(0x49484156454F5054)
+#define NBD_NEW_VERSION UINT64_C(0x49484156454F5054) /* ASCII "IHAVEOPT" */
/* New-style handshake option (sent by the client to us). */
struct nbd_new_option {
- uint64_t version; /* NEW_VERSION */
+ uint64_t version; /* NBD_NEW_VERSION */
uint32_t option; /* NBD_OPT_* */
uint32_t optlen; /* option data length */
/* option data follows */
diff --git a/server/protocol-handshake-newstyle.c b/server/protocol-handshake-newstyle.c
index e46b8255..d0fb4dd7 100644
--- a/server/protocol-handshake-newstyle.c
+++ b/server/protocol-handshake-newstyle.c
@@ -677,7 +677,7 @@ protocol_handshake_newstyle (struct connection *conn)
debug ("newstyle negotiation: flags: global 0x%x", gflags);
- memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
+ handshake.nbdmagic = htobe64 (NBD_MAGIC);
handshake.version = htobe64 (NBD_NEW_VERSION);
handshake.gflags = htobe16 (gflags);
diff --git a/server/protocol-handshake-oldstyle.c b/server/protocol-handshake-oldstyle.c
index 8faa4f03..4efc668b 100644
--- a/server/protocol-handshake-oldstyle.c
+++ b/server/protocol-handshake-oldstyle.c
@@ -60,7 +60,7 @@ protocol_handshake_oldstyle (struct connection *conn)
gflags, eflags);
memset (&handshake, 0, sizeof handshake);
- memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
+ handshake.nbdmagic = htobe64 (NBD_MAGIC);
handshake.version = htobe64 (NBD_OLD_VERSION);
handshake.exportsize = htobe64 (exportsize);
handshake.gflags = htobe16 (gflags);
diff --git a/plugins/nbd/nbd-standalone.c b/plugins/nbd/nbd-standalone.c
index 1789e39c..ab74e1e6 100644
--- a/plugins/nbd/nbd-standalone.c
+++ b/plugins/nbd/nbd-standalone.c
@@ -1018,7 +1018,7 @@ nbd_open_handle (int readonly)
nbdkit_error ("unable to read magic: %m");
goto err;
}
- if (strncmp (old.nbdmagic, "NBDMAGIC", sizeof old.nbdmagic)) {
+ if (be64toh (old.nbdmagic) != NBD_MAGIC) {
nbdkit_error ("wrong magic, %s is not an NBD server", servname);
goto err;
}
diff --git a/tests/test-layers.c b/tests/test-layers.c
index 9bc6532c..93b7770c 100644
--- a/tests/test-layers.c
+++ b/tests/test-layers.c
@@ -174,7 +174,7 @@ main (int argc, char *argv[])
perror ("recv: handshake");
exit (EXIT_FAILURE);
}
- if (memcmp (handshake.nbdmagic, "NBDMAGIC", 8) != 0 ||
+ if (be64toh (handshake.nbdmagic) != NBD_MAGIC ||
be64toh (handshake.version) != NBD_NEW_VERSION) {
fprintf (stderr, "%s: unexpected NBDMAGIC or version\n",
program_name);
--
2.21.0