Add -f option to qemu-nbd. New implementation. Do not need nbd_setup.
Tested and worked.
Signed-off-by: Chunyan Liu <cy...@suse.com>
---
qemu-nbd.c | 71
+++++++++++++++++++++++++++++++++++++++++------------------
1 files changed, 49 insertions(+), 22 deletions(-)
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 291cba2..ba66da1 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -33,7 +33,7 @@
#include <libgen.h>
#include <pthread.h>
-#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
+#define SOCKET_PATH "/var/lock/qemu-nbd-%d"
#define NBD_BUFFER_SIZE (1024*1024)
@@ -53,7 +53,7 @@ static void usage(const char *name)
" -o, --offset=OFFSET offset into the image\n"
" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
" -k, --socket=PATH path to the unix socket\n"
-" (default '"SOCKET_PATH"')\n"
+" (default /var/lock/qemu-nbd-%s)\n"
" -r, --read-only export read-only\n"
" -P, --partition=NUM only expose partition NUM\n"
" -s, --snapshot use snapshot file\n"
@@ -67,7 +67,7 @@ static void usage(const char *name)
" -V, --version output version information and exit\n"
"\n"
"Report bugs to <anth...@codemonkey.ws>\n"
- , name, NBD_DEFAULT_PORT, "DEVICE");
+ , name, NBD_DEFAULT_PORT, "PID");
}
static void version(const char *name)
@@ -194,7 +194,8 @@ static void *show_parts(void *arg)
static void *nbd_client_thread(void *arg)
{
- int fd = *(int *)arg;
+ int fd = -1;
+ int find = *(int *)arg;
off_t size;
size_t blocksize;
uint32_t nbdflags;
@@ -215,9 +216,38 @@ static void *nbd_client_thread(void *arg)
goto out;
}
- ret = nbd_init(fd, sock, nbdflags, size, blocksize);
- if (ret == -1) {
- goto out;
+ if (!find) {
+ fd = open(device, O_RDWR);
+ if (fd == -1) {
+ fprintf(stderr, "Failed to open %s", device);
+ goto out;
+ }
+
+ ret = nbd_init(fd, sock, nbdflags, size, blocksize);
+ if (ret == -1) {
+ goto out;
+ }
+ } else {
+ int i = 0;
+ int max_nbd = 16;
+ for (i = 0; i < max_nbd; i++) {
+ if (!asprintf(&device, "/dev/nbd%d", i)) {
+ continue;
+ }
+
+ fd = open(device, O_RDWR);
+ if (fd == -1 || nbd_init(fd, sock, nbdflags, size, blocksize)
== -1) {
+ free(device);
+ continue;
+ }
+
+ break;
+ }
+
+ if (i >= max_nbd) {
+ fprintf(stderr, "Fail to find a free nbd device\n");
+ goto out;
+ }
}
/* update partition table */
@@ -256,7 +286,7 @@ int main(int argc, char **argv)
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
- const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t";
+ const char *sopt = "hVb:o:p:rsnP:c:dvk:e:tf";
struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
@@ -273,6 +303,7 @@ int main(int argc, char **argv)
{ "shared", 1, NULL, 'e' },
{ "persistent", 0, NULL, 't' },
{ "verbose", 0, NULL, 'v' },
+ { "find", 0, NULL, 'f'},
{ NULL, 0, NULL, 0 }
};
int ch;
@@ -291,6 +322,7 @@ int main(int argc, char **argv)
int nb_fds = 0;
int max_fd;
int persistent = 0;
+ int find = 0;
pthread_t client_thread;
/* The client thread uses SIGTERM to interrupt the server. A signal
@@ -374,6 +406,9 @@ int main(int argc, char **argv)
case 'v':
verbose = 1;
break;
+ case 'f':
+ find = 1;
+ break;
case 'V':
version(argv[0]);
exit(0);
@@ -408,7 +443,7 @@ int main(int argc, char **argv)
return 0;
}
- if (device && !verbose) {
+ if ((device || find) && !verbose) {
int stderr_fd[2];
pid_t pid;
int ret;
@@ -460,18 +495,10 @@ int main(int argc, char **argv)
}
}
- if (device) {
- /* Open before spawning new threads. In the future, we may
- * drop privileges after opening.
- */
- fd = open(device, O_RDWR);
- if (fd == -1) {
- err(EXIT_FAILURE, "Failed to open %s", device);
- }
-
+ if (device || find) {
if (sockpath == NULL) {
sockpath = g_malloc(128);
- snprintf(sockpath, 128, SOCKET_PATH, basename(device));
+ snprintf(sockpath, 128, SOCKET_PATH, getpid());
}
}
@@ -503,10 +530,10 @@ int main(int argc, char **argv)
if (sharing_fds[0] == -1)
return 1;
- if (device) {
+ if (device || find) {
int ret;
- ret = pthread_create(&client_thread, NULL, nbd_client_thread, &fd);
+ ret = pthread_create(&client_thread, NULL, nbd_client_thread,
&find);
if (ret != 0) {
errx(EXIT_FAILURE, "Failed to create client thread: %s",
strerror(ret));
@@ -574,7 +601,7 @@ int main(int argc, char **argv)
unlink(sockpath);
}
- if (device) {
+ if (device || find) {
void *ret;
pthread_join(client_thread, &ret);
exit(ret != NULL);
--
1.7.3.4
2011/12/6 Chunyan Liu <cy...@suse.com>
>
>
> 2011/12/6 Paolo Bonzini <pbonz...@redhat.com>
>
>> On 12/06/2011 09:42 AM, Chunyan Liu wrote:
>>
>>>
>>> I do not understand why you cannot simply do it like this:
>>>
>>> - in the server thread, do everything as it is now
>>>
>>> Nope. When device changes, both client thread and server thread should
>>> be refreshed. sockpath and sharing_fds[] is changed with different
>>> device.
>>>
>>
>> Then let's change the default sockpath to include the pid rather than the
>> NBD device name.
>>
>> Sounds good. Will try. Thanks.
>
>
>> Paolo
>>
>>
>
