On Thu, Nov 07, 2013 at 10:20:33PM -0600, Serge Hallyn wrote: > lxc-start is not safe (and doesn't actually make sense) if the > task is nto single-threaded. > > Signed-off-by: Serge Hallyn <serge.hal...@ubuntu.com>
Acked-by: Stéphane Graber <stgra...@ubuntu.com>
> ---
> src/lxc/lxccontainer.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 05e5405..827cae0 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -506,6 +506,38 @@ static bool wait_on_daemonized_start(struct
> lxc_container *c)
> return lxcapi_wait(c, "RUNNING", timeout);
> }
>
> +static bool am_single_threaded(void)
> +{
> + struct dirent dirent, *direntp;
> + DIR *dir;
> + int count=0;
> +
> + process_lock();
> + dir = opendir("/proc/self/task");
> + process_unlock();
> + if (!dir) {
> + INFO("failed to open /proc/self/task");
> + return false;
> + }
> +
> + while (!readdir_r(dir, &dirent, &direntp)) {
> + if (!direntp)
> + break;
> +
> + if (!strcmp(direntp->d_name, "."))
> + continue;
> +
> + if (!strcmp(direntp->d_name, ".."))
> + continue;
> + if (++count > 1)
> + break;
> + }
> + process_lock();
> + closedir(dir);
> + process_unlock();
> + return count == 1;
> +}
> +
> /*
> * I can't decide if it'd be more convenient for callers if we accept '...',
> * or a null-terminated array (i.e. execl vs execv)
> @@ -598,6 +630,11 @@ static bool lxcapi_start(struct lxc_container *c, int
> useinit, char * const argv
> open("/dev/null", O_RDWR);
> open("/dev/null", O_RDWR);
> setsid();
> + } else {
> + if (!am_single_threaded()) {
> + ERROR("Cannot start non-daemonized container when
> threaded");
> + return false;
> + }
> }
>
> reboot:
> --
> 1.8.3.2
>
>
> ------------------------------------------------------------------------------
> November Webinars for C, C++, Fortran Developers
> Accelerate application performance with scalable programming models. Explore
> techniques for threading, error checking, porting, and tuning. Get the most
> from the latest Intel processors and coprocessors. See abstracts and register
> http://pubads.g.doubleclick.net/gampad/clk?id=60136231&iu=/4140/ostg.clktrk
> _______________________________________________
> Lxc-devel mailing list
> Lxc-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lxc-devel
--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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