run qemu-nbd as an inetd service has some benefits
* more scriptable, such as serve multiple images to different clients
on one ip/port
* access control using tcpd
simple usage:
#!/bin/sh
# qemu-nbd wrapper, select image file according to client ip address
IMG_FILE=`sed -n "s/$REMOTE_HOST //p" /path/to/image_list.txt`
qemu-nbd -i 10 $IMG_FILE 10<&0- 1>/tmp/log 2>/tmp/log2
#end
#xinetd.conf
service nbd
{
flags = REUSE
socket_type = stream
wait = no
user = some_user
server = /path/to/qemu-nbd-wrapper.sh
log_on_failure += USERID
disable = no
}
Signed-off-by: Jun Sheng <chaoseter...@gmail.com>
---
qemu-nbd.c | 42 ++++++++++++++++++++++++++++++++++--------
1 file changed, 34 insertions(+), 8 deletions(-)
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 5cd6c6d..f4af4c7 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -49,6 +49,7 @@ static NBDExport *exp;
static int verbose;
static char *srcpath;
static char *sockpath;
+static int inetd_fd = -1;
static int persistent = 0;
static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
static int shared = 1;
@@ -66,6 +67,7 @@ static void usage(const char *name)
"Connection properties:\n"
" -p, --port=PORT port to listen on (default `%d')\n"
" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
+" -i, --inetd=FD run as an inetd services on FD\n"
" -k, --socket=PATH path to the unix socket\n"
" (default '"SOCKET_PATH"')\n"
" -e, --shared=NUM device can be shared by NUM clients (default
'1')\n"
@@ -363,7 +365,13 @@ static void nbd_accept(void *opaque)
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
- int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
+ int fd;
+ if (inetd_fd < 0) {
+ fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
+ } else {
+ fd = server_fd;
+ }
+
if (fd < 0) {
perror("accept");
return;
@@ -396,10 +404,11 @@ int main(int argc, char **argv)
off_t fd_size;
QemuOpts *sn_opts = NULL;
const char *sn_id_or_name = NULL;
- const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:";
+ const char *sopt = "hVi:b:o:p:rsnP:c:dvk:e:f:tl:";
struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
+ { "inetd", 1, NULL, 'i'},
{ "bind", 1, NULL, 'b' },
{ "port", 1, NULL, 'p' },
{ "socket", 1, NULL, 'k' },
@@ -508,6 +517,16 @@ int main(int argc, char **argv)
"without setting discard operation to
unmap");
}
break;
+ case 'i':
+ inetd_fd = qemu_parse_fd(optarg);
+ if (inetd_fd < 0) {
+ errx(EXIT_FAILURE, "Invalid inet fd `%s'", optarg);
+ }
+ if (inetd_fd <= STDERR_FILENO) {
+ errx(EXIT_FAILURE, "Inet fd out of range `%s',"
+ " should be in [3, 65535]", optarg);
+ }
+ break;
case 'b':
bindto = optarg;
break;
@@ -732,10 +751,14 @@ int main(int argc, char **argv)
exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
- if (sockpath) {
- fd = unix_socket_incoming(sockpath);
+ if (inetd_fd < 0) {
+ if (sockpath) {
+ fd = unix_socket_incoming(sockpath);
+ } else {
+ fd = tcp_socket_incoming(bindto, port);
+ }
} else {
- fd = tcp_socket_incoming(bindto, port);
+ fd = inetd_fd;
}
if (fd < 0) {
@@ -754,9 +777,12 @@ int main(int argc, char **argv)
/* Shut up GCC warnings. */
memset(&client_thread, 0, sizeof(client_thread));
}
-
- qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
- (void *)(uintptr_t)fd);
+ if (inetd_fd < 0) {
+ qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
+ (void *)(uintptr_t)fd);
+ } else {
+ nbd_accept((void *)(uintptr_t)fd);
+ }
/* now when the initialization is (almost) complete, chdir("/")
* to free any busy filesystems */
--
2.1.2
