[lxc-devel] [PATCH] cgmanager: also handle named subsystems (like name=systemd)

[Stéphane Graber]

On Fri, May 02, 2014 at 01:36:32PM -0500, Serge Hallyn wrote:
> Read /proc/self/cgroup instead of /proc/cgroups, so as to catch
> named subsystems.  Otherwise the contaienrs will not be fully
> moved into the container cgroups.
> 
> Also free line which was being leaked.
> 
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>

Acked-by: Stéphane Graber <stgraber at ubuntu.com>

> ---
>  src/lxc/cgmanager.c | 51 +++++++++++++++++++++++++++++++++------------------
>  1 file changed, 33 insertions(+), 18 deletions(-)
> 
> diff --git a/src/lxc/cgmanager.c b/src/lxc/cgmanager.c
> index fc959ec..ab061e4 100644
> --- a/src/lxc/cgmanager.c
> +++ b/src/lxc/cgmanager.c
> @@ -758,39 +758,53 @@ static void free_subsystems(void)
>  
>  static bool collect_subsytems(void)
>  {
> -	char *line = NULL, *tab1;
> +	char *line = NULL;
>  	size_t sz = 0;
>  	FILE *f;
>  
>  	if (subsystems) // already initialized
>  		return true;
>  
> -	f = fopen_cloexec("/proc/cgroups", "r");
> +	f = fopen_cloexec("/proc/self/cgroup", "r");
>  	if (!f) {
> -		return false;
> +		f = fopen_cloexec("/proc/1/cgroup", "r");
> +		if (!f)
> +			return false;
>  	}
>  	while (getline(&line, &sz, f) != -1) {
> -		char **tmp;
> -		if (line[0] == '#')
> -			continue;
> +		/* file format: hierarchy:subsystems:group,
> +		 * with multiple subsystems being ,-separated */
> +		char *slist, *end, *p, *saveptr = NULL, **tmp;
> +
>  		if (!line[0])
>  			continue;
> -		tab1 = strchr(line, '\t');
> -		if (!tab1)
> +
> +		slist = strchr(line, ':');
> +		if (!slist)
> +			continue;
> +		slist++;
> +		end = strchr(slist, ':');
> +		if (!end)
>  			continue;
> -		*tab1 = '\0';
> -		tmp = realloc(subsystems, (nr_subsystems+1)*sizeof(char *));
> -		if (!tmp)
> -			goto out_free;
> -
> -		subsystems = tmp;
> -		tmp[nr_subsystems] = strdup(line);
> -		if (!tmp[nr_subsystems])
> -			goto out_free;
> -		nr_subsystems++;
> +		*end = '\0';
> +
> +		for (p = strtok_r(slist, ",", &saveptr);
> +				p;
> +				p = strtok_r(NULL, ",", &saveptr)) {
> +			tmp = realloc(subsystems, (nr_subsystems+1)*sizeof(char *));
> +			if (!tmp)
> +				goto out_free;
> +
> +			subsystems = tmp;
> +			tmp[nr_subsystems] = strdup(p);
> +			if (!tmp[nr_subsystems])
> +				goto out_free;
> +			nr_subsystems++;
> +		}
>  	}
>  	fclose(f);
>  
> +	free(line);
>  	if (!nr_subsystems) {
>  		ERROR("No cgroup subsystems found");
>  		return false;
> @@ -799,6 +813,7 @@ static bool collect_subsytems(void)
>  	return true;
>  
>  out_free:
> +	free(line);
>  	fclose(f);
>  	free_subsystems();
>  	return false;
> -- 
> 1.9.1
> 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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