On 13.04.2017 00:11, Richard W.M. Jones wrote:
On Wed, Apr 12, 2017 at 05:01:10PM +0300, Pavel Butsykin wrote:
Add udev_settle_file() to run 'udevadm settle' with --exit-if-exists option. It
will slightly reduce the waiting-time for pending events if we need to wait
for events related to a particular device/file.
Signed-off-by: Pavel Butsykin <[email protected]>
---
daemon/daemon.h | 2 ++
daemon/guestfsd.c | 20 ++++++++++++++++----
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/daemon/daemon.h b/daemon/daemon.h
index 79a5288f6..90ebaafbe 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -141,6 +141,8 @@ extern int parse_btrfsvol (const char *desc, mountable_t
*mountable);
extern int prog_exists (const char *prog);
+extern void udev_settle_file (const char *file);
+
extern void udev_settle (void);
extern int random_name (char *template);
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index 85ce5d2ad..dccfa15bc 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -1213,13 +1213,18 @@ random_name (char *template)
* fussed if it fails.
*/
void
-udev_settle (void)
+udev_settle_file (const char *file)
{
- char cmd[80];
+ size_t cmd_size = strlen (str_udevadm) +
+ sizeof (" settle") +
+ sizeof (" --debug") +
+ (file ? sizeof (" --exit-if-exists=") + strlen (file) : 0);
+ char *cmd = malloc (cmd_size);
int r;
- snprintf (cmd, sizeof cmd, "%s%s settle",
- str_udevadm, verbose ? " --debug" : "");
+ snprintf(cmd, cmd_size, "%s%s settle%s%s",
+ str_udevadm, verbose ? " --debug" : "",
+ file ? " --exit-if-exists=" : "", file ? file : "");
if (verbose)
printf ("%s\n", cmd);
r = system (cmd);
@@ -1227,6 +1232,13 @@ udev_settle (void)
perror ("system");
else if (!WIFEXITED (r) || WEXITSTATUS (r) != 0)
fprintf (stderr, "warning: udevadm command failed\n");
+ free (cmd);
There are some ugly quoting (and hence, possibly, security) problems
with this patch.
It's more secure and also much simpler to call ADD_ARG + commandv
here. For an example of how to use it, see:
https://github.com/libguestfs/libguestfs/blob/master/daemon/mkfs.c#L41-L247
I agree, it would be better, thanks!
Rich.
_______________________________________________
Libguestfs mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/libguestfs
