[libvirt] [PATCH] Don't use O_TRUNC when opening QEMU logfiles
Jiri Denemark
jdenemar at redhat.com
Fri Sep 21 09:51:06 UTC 2012
On Fri, Sep 21, 2012 at 10:39:19 +0100, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
>
> SELinux wants all log files opened with O_APPEND. When
> running non-root though, libvirtd likes to use O_TRUNC
> to avoid log files growing in size indefinitely. Instead
> of using O_TRUNC though, we can use O_APPEND and then
> call ftruncate() which keeps SELinux happier.
>
> Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> ---
> src/qemu/qemu_domain.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 0ae30b7..e67c247 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -1446,12 +1446,22 @@ qemuDomainOpenLogHelper(struct qemud_driver *driver,
> {
> char *logfile;
> int fd = -1;
> + bool trunc = false;
>
> if (virAsprintf(&logfile, "%s/%s.log", driver->logDir, vm->def->name) < 0) {
> virReportOOMError();
> return -1;
> }
>
> + /* To make SELinux happy we always need to open in append mode.
> + * So we fake O_TRUNC by calling ftruncate after open instead
> + */
> + if (oflags & O_TRUNC) {
> + oflags &= ~O_TRUNC;
> + oflags |= O_APPEND;
> + trunc = true;
> + }
> +
> if ((fd = open(logfile, oflags, mode)) < 0) {
> virReportSystemError(errno, _("failed to create logfile %s"),
> logfile);
> @@ -1463,6 +1473,13 @@ qemuDomainOpenLogHelper(struct qemud_driver *driver,
> VIR_FORCE_CLOSE(fd);
> goto cleanup;
> }
> + if (trunc &&
> + ftruncate(fd, 0) < 0) {
> + virReportSystemError(errno, _("failed to truncate %s"),
> + logfile);
> + VIR_FORCE_CLOSE(fd);
> + goto cleanup;
> + }
I wonder if it's necessary to fail here or if VIR_WARN would be sufficient.
ACK in any case.
Jirka
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