5:28 a.m.
The previous patch guarantees that start_nbdkit() is only called with a
non-NULL "fds" parameter (and, consequently, that start_nbdkit() does not
use "ipaddr" and "port" for anything beyond logging).
Remove the branch in start_nbdkit() that starts nbdkit without socket
activation, and trim the start_nbdkit() prototype too.
This patch is best viewed with "git show -b" due to the unindentation in
it.
Ref: https://listman.redhat.com/archives/libguestfs/2022-March/028475.html
Suggested-by: Richard W.M. Jones <rjones(a)redhat.com>
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
Reviewed-by: Richard W.M. Jones <rjones(a)redhat.com>
---
Notes:
v2:
- pick up Rich's R-b
nbd.c | 54 ++++++--------------
1 file changed, 16 insertions(+), 38 deletions(-)
diff --git a/nbd.c b/nbd.c
index edc3ab51d889..cda962d03bdd 100644
--- a/nbd.c
+++ b/nbd.c
@@ -80,7 +80,7 @@ static const enum nbd_server standard_servers[] =
*/
static enum nbd_server use_server;
-static pid_t start_nbdkit (const char *device, const char *ipaddr, int port, int *fds,
size_t nr_fds);
+static pid_t start_nbdkit (const char *device, int *fds, size_t nr_fds);
static int open_listening_socket (const char *ipaddr, int **fds, size_t *nr_fds);
static int bind_tcpip_socket (const char *ipaddr, const char *port, int **fds, size_t
*nr_fds);
static int connect_with_source_port (const char *hostname, int dest_port, int
source_port);
@@ -238,29 +238,29 @@ pid_t
start_nbd_server (const char **ipaddr, int *port, const char *device)
{
int *fds = NULL;
size_t i, nr_fds;
pid_t pid;
switch (use_server) {
case NBDKIT: /* nbdkit with socket activation */
*ipaddr = "localhost";
*port = open_listening_socket (*ipaddr, &fds, &nr_fds);
if (*port == -1) return -1;
- pid = start_nbdkit (device, *ipaddr, *port, fds, nr_fds);
+ pid = start_nbdkit (device, fds, nr_fds);
for (i = 0; i < nr_fds; ++i)
close (fds[i]);
free (fds);
return pid;
}
abort ();
}
#define FIRST_SOCKET_ACTIVATION_FD 3
/**
* Set up file descriptors and environment variables for
* socket activation.
*
* Note this function runs in the child between fork and exec.
*/
@@ -268,106 +268,84 @@ static inline void
socket_activation (int *fds, size_t nr_fds)
{
size_t i;
char nr_fds_str[16];
char pid_str[16];
if (fds == NULL) return;
for (i = 0; i < nr_fds; ++i) {
int fd = FIRST_SOCKET_ACTIVATION_FD + i;
if (fds[i] != fd) {
dup2 (fds[i], fd);
close (fds[i]);
}
}
snprintf (nr_fds_str, sizeof nr_fds_str, "%zu", nr_fds);
setenv ("LISTEN_FDS", nr_fds_str, 1);
snprintf (pid_str, sizeof pid_str, "%d", (int) getpid ());
setenv ("LISTEN_PID", pid_str, 1);
}
/**
* Start a local L<nbdkit(1)> process using the
* L<nbdkit-file-plugin(1)>.
*
- * If we are using socket activation, C<fds> and C<nr_fds> will
- * contain the locally pre-opened file descriptors for this.
- * Otherwise if C<fds == NULL> we pass the port number.
+ * C<fds> and C<nr_fds> will contain the locally pre-opened file descriptors
+ * for this.
*
* Returns the process ID (E<gt> 0) or C<0> if there is an error.
*/
static pid_t
-start_nbdkit (const char *device,
- const char *ipaddr, int port, int *fds, size_t nr_fds)
+start_nbdkit (const char *device, int *fds, size_t nr_fds)
{
pid_t pid;
- char port_str[64];
CLEANUP_FREE char *file_str = NULL;
#if DEBUG_STDERR
- fprintf (stderr, "starting nbdkit for %s on %s:%d%s\n",
- device, ipaddr, port,
- fds == NULL ? "" : " using socket activation");
+ fprintf (stderr, "starting nbdkit for %s using socket activation\n",
device);
#endif
- snprintf (port_str, sizeof port_str, "%d", port);
-
if (asprintf (&file_str, "file=%s", device) == -1)
error (EXIT_FAILURE, errno, "asprintf");
pid = fork ();
if (pid == -1) {
set_nbd_error ("fork: %m");
return 0;
}
if (pid == 0) { /* Child. */
close (0);
if (open ("/dev/null", O_RDONLY) == -1) {
perror ("open: /dev/null");
_exit (EXIT_FAILURE);
}
- if (fds == NULL) { /* without socket activation */
- execlp ("nbdkit",
- "nbdkit",
- "-r", /* readonly (vital!) */
- "-p", port_str, /* listening port */
- "-i", ipaddr, /* listen only on loopback interface */
- "-f", /* don't fork */
- "file", /* file plugin */
- file_str, /* a device like file=/dev/sda */
- NULL);
- perror ("nbdkit");
- _exit (EXIT_FAILURE);
- }
- else { /* socket activation */
- socket_activation (fds, nr_fds);
+ socket_activation (fds, nr_fds);
- execlp ("nbdkit",
- "nbdkit",
- "-r", /* readonly (vital!) */
- "-f", /* don't fork */
- "file", /* file plugin */
- file_str, /* a device like file=/dev/sda */
- NULL);
- perror ("nbdkit");
- _exit (EXIT_FAILURE);
- }
+ execlp ("nbdkit",
+ "nbdkit",
+ "-r", /* readonly (vital!) */
+ "-f", /* don't fork */
+ "file", /* file plugin */
+ file_str, /* a device like file=/dev/sda */
+ NULL);
+ perror ("nbdkit");
+ _exit (EXIT_FAILURE);
}
/* Parent. */
return pid;
}
/**
* This is used when we are starting an NBD server which supports
* socket activation. We can open a listening socket on an unused
* local port and return it.
*
* Returns the port number on success or C<-1> on error.
*
* The file descriptor(s) bound are returned in the array *fds, *nr_fds.
* The caller must free the array.
*/
--
2.19.1.3.g30247aa5d201