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authorEric Blake <eblake@redhat.com>2018-12-15 07:53:08 -0600
committerEric Blake <eblake@redhat.com>2019-01-05 07:50:22 -0600
commit3c1fa35d74aabe9c3ab642d2591b087e53d7a616 (patch)
treed8225f4f4749c94717dbf84457744100440a52f4
parent6c5c035138218a384a229e7b6b9cf51451621c6a (diff)
downloadqemu-arm-3c1fa35d74aabe9c3ab642d2591b087e53d7a616.tar.gz
qemu-nbd: Fail earlier for -c/-d on non-linux
Connecting to a /dev/nbdN device is a Linux-specific action. We were already masking -c and -d from 'qemu-nbd --help' on non-linux. However, while -d fails with a sensible error message, it took hunting through a couple of files to prove that. What's more, the code for -c doesn't fail until after it has created a pthread and tried to open a device - possibly even printing an error message with %m on a non-Linux platform in spite of the comment that %m is glibc-specific. Make the failure happen sooner, then get rid of stubs that are no longer needed because of the early exits. While at it: tweak the blank newlines in --help output to be consistent, whether or not built on Linux. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20181215135324.152629-7-eblake@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
-rw-r--r--nbd/client.c18
-rw-r--r--qemu-nbd.c21
2 files changed, 20 insertions, 19 deletions
diff --git a/nbd/client.c b/nbd/client.c
index e77414711b..5a03a84418 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -1031,23 +1031,7 @@ int nbd_disconnect(int fd)
return 0;
}
-#else
-int nbd_init(int fd, QIOChannelSocket *ioc, NBDExportInfo *info,
- Error **errp)
-{
- error_setg(errp, "nbd_init is only supported on Linux");
- return -ENOTSUP;
-}
-
-int nbd_client(int fd)
-{
- return -ENOTSUP;
-}
-int nbd_disconnect(int fd)
-{
- return -ENOTSUP;
-}
-#endif
+#endif /* __linux__ */
int nbd_send_request(QIOChannel *ioc, NBDRequest *request)
{
diff --git a/qemu-nbd.c b/qemu-nbd.c
index e169b839ec..2807e13239 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -43,6 +43,12 @@
#include "trace/control.h"
#include "qemu-version.h"
+#ifdef __linux__
+#define HAVE_NBD_DEVICE 1
+#else
+#define HAVE_NBD_DEVICE 0
+#endif
+
#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
#define QEMU_NBD_OPT_CACHE 256
#define QEMU_NBD_OPT_AIO 257
@@ -98,11 +104,11 @@ static void usage(const char *name)
" specify tracing options\n"
" --fork fork off the server process and exit the parent\n"
" once the server is running\n"
-#ifdef __linux__
+#if HAVE_NBD_DEVICE
+"\n"
"Kernel NBD client support:\n"
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
-"\n"
#endif
"\n"
"Block device options:\n"
@@ -236,6 +242,7 @@ static void termsig_handler(int signum)
}
+#if HAVE_NBD_DEVICE
static void *show_parts(void *arg)
{
char *device = arg;
@@ -321,6 +328,7 @@ out:
kill(getpid(), SIGTERM);
return (void *) EXIT_FAILURE;
}
+#endif /* HAVE_NBD_DEVICE */
static int nbd_can_accept(void)
{
@@ -814,6 +822,12 @@ int main(int argc, char **argv)
}
}
+#if !HAVE_NBD_DEVICE
+ if (disconnect || device) {
+ error_report("Kernel /dev/nbdN support not available");
+ exit(EXIT_FAILURE);
+ }
+#else /* HAVE_NBD_DEVICE */
if (disconnect) {
int nbdfd = open(argv[optind], O_RDWR);
if (nbdfd < 0) {
@@ -829,6 +843,7 @@ int main(int argc, char **argv)
return 0;
}
+#endif
if ((device && !verbose) || fork_process) {
int stderr_fd[2];
@@ -1006,6 +1021,7 @@ int main(int argc, char **argv)
nbd_export_set_description(exp, export_description);
if (device) {
+#if HAVE_NBD_DEVICE
int ret;
ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
@@ -1013,6 +1029,7 @@ int main(int argc, char **argv)
error_report("Failed to create client thread: %s", strerror(ret));
exit(EXIT_FAILURE);
}
+#endif
} else {
/* Shut up GCC warnings. */
memset(&client_thread, 0, sizeof(client_thread));