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authorths <ths@c046a42c-6fe2-441c-8c8c-71466251a162>2008-07-03 12:45:02 +0000
committerths <ths@c046a42c-6fe2-441c-8c8c-71466251a162>2008-07-03 12:45:02 +0000
commit3b05a8e91bf15e1858f3f3618069dbc78e55b88e (patch)
tree99dcfae1de91d07cf05ad8c88edbd021fb87f83d
parentAdd a parameter to disable host cache, by Laurent Vivier. (diff)
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Allow to share a disk image via nbd, by Laurent Vivier.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4837 c046a42c-6fe2-441c-8c8c-71466251a162
-rw-r--r--qemu-nbd.c96
-rw-r--r--qemu-nbd.texi2
2 files changed, 77 insertions, 21 deletions
diff --git a/qemu-nbd.c b/qemu-nbd.c
index bac0e4f16..605d4e324 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -55,6 +55,7 @@ static void usage(const char *name)
" -n, --nocache disable host cache\n"
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
+" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
" -v, --verbose display extra debugging information\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
@@ -182,14 +183,13 @@ int main(int argc, char **argv)
bool disconnect = false;
const char *bindto = "0.0.0.0";
int port = 1024;
- int sock, csock;
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
char *device = NULL;
char *socket = NULL;
char sockpath[128];
- const char *sopt = "hVbo:p:rsnP:c:dvk:";
+ const char *sopt = "hVbo:p:rsnP:c:dvk:e:";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
@@ -203,6 +203,7 @@ int main(int argc, char **argv)
{ "disconnect", 0, 0, 'd' },
{ "snapshot", 0, 0, 's' },
{ "nocache", 0, 0, 'n' },
+ { "shared", 1, 0, 'e' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
};
@@ -212,9 +213,15 @@ int main(int argc, char **argv)
char *end;
int flags = 0;
int partition = -1;
- int fd;
int ret;
+ int shared = 1;
uint8_t *data;
+ fd_set fds;
+ int *sharing_fds;
+ int fd;
+ int i;
+ int nb_fds = 0;
+ int max_fd;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@@ -267,6 +274,15 @@ int main(int argc, char **argv)
case 'c':
device = optarg;
break;
+ case 'e':
+ shared = strtol(optarg, &end, 0);
+ if (*end) {
+ errx(EINVAL, "Invalid shared device number '%s'", optarg);
+ }
+ if (shared < 1) {
+ errx(EINVAL, "Shared device number must be greater than 0\n");
+ }
+ break;
case 'v':
verbose = 1;
break;
@@ -320,8 +336,10 @@ int main(int argc, char **argv)
errx(errno, "Could not find partition %d", partition);
if (device) {
- pid_t pid;
- if (!verbose)
+ pid_t pid;
+ int sock;
+
+ if (!verbose)
daemon(0, 0); /* detach client and server */
if (socket == NULL) {
@@ -384,33 +402,69 @@ int main(int argc, char **argv)
/* children */
}
+ sharing_fds = qemu_malloc((shared + 1) * sizeof(int));
+ if (sharing_fds == NULL)
+ errx(ENOMEM, "Cannot allocate sharing fds");
+
if (socket) {
- sock = unix_socket_incoming(socket);
+ sharing_fds[0] = unix_socket_incoming(socket);
} else {
- sock = tcp_socket_incoming(bindto, port);
+ sharing_fds[0] = tcp_socket_incoming(bindto, port);
}
- if (sock == -1)
+ if (sharing_fds[0] == -1)
return 1;
+ max_fd = sharing_fds[0];
+ nb_fds++;
- csock = accept(sock,
- (struct sockaddr *)&addr,
- &addr_len);
- if (csock == -1)
- return 1;
+ data = qemu_memalign(512, NBD_BUFFER_SIZE);
+ if (data == NULL)
+ errx(ENOMEM, "Cannot allocate data buffer");
- /* new fd_size is calculated by find_partition */
- if (nbd_negotiate(bs, csock, fd_size) == -1)
- return 1;
+ do {
- data = qemu_memalign(512, NBD_BUFFER_SIZE);
- while (nbd_trip(bs, csock, fd_size, dev_offset, &offset, readonly,
- data, NBD_BUFFER_SIZE) == 0);
+ FD_ZERO(&fds);
+ for (i = 0; i < nb_fds; i++)
+ FD_SET(sharing_fds[i], &fds);
+
+ ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
+ if (ret == -1)
+ break;
+
+ if (FD_ISSET(sharing_fds[0], &fds))
+ ret--;
+ for (i = 1; i < nb_fds && ret; i++) {
+ if (FD_ISSET(sharing_fds[i], &fds)) {
+ if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset,
+ &offset, readonly, data, NBD_BUFFER_SIZE) != 0) {
+ close(sharing_fds[i]);
+ nb_fds--;
+ sharing_fds[i] = sharing_fds[nb_fds];
+ i--;
+ }
+ ret--;
+ }
+ }
+ /* new connection ? */
+ if (FD_ISSET(sharing_fds[0], &fds)) {
+ if (nb_fds < shared + 1) {
+ sharing_fds[nb_fds] = accept(sharing_fds[0],
+ (struct sockaddr *)&addr,
+ &addr_len);
+ if (sharing_fds[nb_fds] != -1 &&
+ nbd_negotiate(bs, sharing_fds[nb_fds], fd_size) != -1) {
+ if (sharing_fds[nb_fds] > max_fd)
+ max_fd = sharing_fds[nb_fds];
+ nb_fds++;
+ }
+ }
+ }
+ } while (nb_fds > 1);
qemu_free(data);
- close(csock);
- close(sock);
+ close(sharing_fds[0]);
bdrv_close(bs);
+ qemu_free(sharing_fds);
if (socket)
unlink(socket);
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 3a4cb9254..b196a3471 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -34,6 +34,8 @@ Export Qemu disk image using NBD protocol.
connect FILE to NBD device DEV
@item -d, --disconnect
disconnect the specified device
+@item -e, --shared=NUM
+ device can be shared by NUM clients (default '1')
@item -v, --verbose
display extra debugging information
@item -h, --help