On Sat, Jan 11, 2014 at 12:14:26AM -0600, Serge Hallyn wrote: > Currently when a container is shut down, lxc walks the set of all > cgroup paths it created, in reverse order, and tries to remove them. > This doesn't suffice if the container has also created new cgroups. > > It'd be impolite to recursively remove all the cgroup paths we created, > since this can include '/lxc' and thereunder all other containers > started since. > > This patch changes container shutdown to only delete the container's own > path, but do so recursively. Note that if we fail during startup, > the container won't have created any cgroup paths so it the old > way works fine. > > Signed-off-by: Serge Hallyn <serge.hal...@ubuntu.com>
Acked-by: Stéphane Graber <stgra...@ubuntu.com>
> ---
> src/lxc/cgroup.c | 101
> ++++++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 88 insertions(+), 13 deletions(-)
>
> diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
> index b1196b4..be43c73 100644
> --- a/src/lxc/cgroup.c
> +++ b/src/lxc/cgroup.c
> @@ -68,9 +68,9 @@ static char **subsystems_from_mount_options(const char
> *mount_options, char **ke
> static void lxc_cgroup_mount_point_free(struct cgroup_mount_point *mp);
> static void lxc_cgroup_hierarchy_free(struct cgroup_hierarchy *h);
> static bool is_valid_cgroup(const char *name);
> -static int create_or_remove_cgroup(bool remove, struct cgroup_mount_point
> *mp, const char *path);
> +static int create_or_remove_cgroup(bool remove, struct cgroup_mount_point
> *mp, const char *path, int recurse);
> static int create_cgroup(struct cgroup_mount_point *mp, const char *path);
> -static int remove_cgroup(struct cgroup_mount_point *mp, const char *path);
> +static int remove_cgroup(struct cgroup_mount_point *mp, const char *path,
> bool recurse);
> static char *cgroup_to_absolute_path(struct cgroup_mount_point *mp, const
> char *path, const char *suffix);
> static struct cgroup_process_info *find_info_for_subsystem(struct
> cgroup_process_info *info, const char *subsystem);
> static int do_cgroup_get(const char *cgroup_path, const char *sub_filename,
> char *value, size_t len);
> @@ -81,6 +81,75 @@ static int cgroup_recursive_task_count(const char
> *cgroup_path);
> static int count_lines(const char *fn);
> static int handle_cgroup_settings(struct cgroup_mount_point *mp, char
> *cgroup_path);
>
> +static int cgroup_rmdir(char *dirname)
> +{
> + struct dirent dirent, *direntp;
> + int saved_errno = 0;
> + DIR *dir;
> + int ret, failed=0;
> + char pathname[MAXPATHLEN];
> +
> + dir = opendir(dirname);
> + if (!dir) {
> + ERROR("%s: failed to open %s", __func__, dirname);
> + return -1;
> + }
> +
> + while (!readdir_r(dir, &dirent, &direntp)) {
> + struct stat mystat;
> + int rc;
> +
> + if (!direntp)
> + break;
> +
> + if (!strcmp(direntp->d_name, ".") ||
> + !strcmp(direntp->d_name, ".."))
> + continue;
> +
> + rc = snprintf(pathname, MAXPATHLEN, "%s/%s", dirname,
> direntp->d_name);
> + if (rc < 0 || rc >= MAXPATHLEN) {
> + ERROR("pathname too long");
> + failed=1;
> + if (!saved_errno)
> + saved_errno = -ENOMEM;
> + continue;
> + }
> + ret = lstat(pathname, &mystat);
> + if (ret) {
> + SYSERROR("%s: failed to stat %s", __func__, pathname);
> + failed=1;
> + if (!saved_errno)
> + saved_errno = errno;
> + continue;
> + }
> + if (S_ISDIR(mystat.st_mode)) {
> + if (cgroup_rmdir(pathname) < 0) {
> + if (!saved_errno)
> + saved_errno = errno;
> + failed=1;
> + }
> + }
> + }
> +
> + if (rmdir(dirname) < 0) {
> + SYSERROR("%s: failed to delete %s", __func__, dirname);
> + if (!saved_errno)
> + saved_errno = errno;
> + failed=1;
> + }
> +
> + ret = closedir(dir);
> + if (ret) {
> + SYSERROR("%s: failed to close directory %s", __func__, dirname);
> + if (!saved_errno)
> + saved_errno = errno;
> + failed=1;
> + }
> +
> + errno = saved_errno;
> + return failed ? -1 : 0;
> +}
> +
> struct cgroup_meta_data *lxc_cgroup_load_meta()
> {
> const char *cgroup_use = NULL;
> @@ -745,7 +814,7 @@ extern struct cgroup_process_info
> *lxc_cgroup_create(const char *name, const cha
> * In that case, remove the cgroup from all previous hierarchies
> */
> for (j = 0, info_ptr = base_info; j < i && info_ptr; info_ptr =
> info_ptr->next, j++) {
> - r = remove_cgroup(info_ptr->designated_mount_point,
> info_ptr->created_paths[info_ptr->created_paths_count - 1]);
> + r = remove_cgroup(info_ptr->designated_mount_point,
> info_ptr->created_paths[info_ptr->created_paths_count - 1], false);
> if (r < 0)
> WARN("could not clean up cgroup we created when
> trying to create container");
>
> free(info_ptr->created_paths[info_ptr->created_paths_count - 1]);
> @@ -1039,8 +1108,7 @@ void lxc_cgroup_process_info_free_and_remove(struct
> cgroup_process_info *info)
> if (!info)
> return;
> next = info->next;
> - for (pp = info->created_paths; pp && *pp; pp++);
> - for ((void)(pp && --pp); info->created_paths && pp >=
> info->created_paths; --pp) {
> + {
> struct cgroup_mount_point *mp = info->designated_mount_point;
> if (!mp)
> mp = lxc_cgroup_find_mount_point(info->hierarchy,
> info->cgroup_path, true);
> @@ -1049,7 +1117,10 @@ void lxc_cgroup_process_info_free_and_remove(struct
> cgroup_process_info *info)
> * '/lxc' cgroup in this container but another container
> * is still running (for example)
> */
> - (void)remove_cgroup(mp, *pp);
> + (void)remove_cgroup(mp, info->cgroup_path, true);
> + }
> + for (pp = info->created_paths; pp && *pp; pp++);
> + for ((void)(pp && --pp); info->created_paths && pp >=
> info->created_paths; --pp) {
> free(*pp);
> }
> free(info->created_paths);
> @@ -1609,7 +1680,7 @@ bool is_valid_cgroup(const char *name)
> return strcmp(name, ".") != 0 && strcmp(name, "..") != 0;
> }
>
> -int create_or_remove_cgroup(bool do_remove, struct cgroup_mount_point *mp,
> const char *path)
> +int create_or_remove_cgroup(bool do_remove, struct cgroup_mount_point *mp,
> const char *path, int recurse)
> {
> int r, saved_errno = 0;
> char *buf = cgroup_to_absolute_path(mp, path, NULL);
> @@ -1617,9 +1688,13 @@ int create_or_remove_cgroup(bool do_remove, struct
> cgroup_mount_point *mp, const
> return -1;
>
> /* create or remove directory */
> - r = do_remove ?
> - rmdir(buf) :
> - mkdir(buf, 0777);
> + if (do_remove) {
> + if (recurse)
> + r = cgroup_rmdir(buf);
> + else
> + r = rmdir(buf);
> + } else
> + r = mkdir(buf, 0777);
> saved_errno = errno;
> free(buf);
> errno = saved_errno;
> @@ -1628,12 +1703,12 @@ int create_or_remove_cgroup(bool do_remove, struct
> cgroup_mount_point *mp, const
>
> int create_cgroup(struct cgroup_mount_point *mp, const char *path)
> {
> - return create_or_remove_cgroup(false, mp, path);
> + return create_or_remove_cgroup(false, mp, path, false);
> }
>
> -int remove_cgroup(struct cgroup_mount_point *mp, const char *path)
> +int remove_cgroup(struct cgroup_mount_point *mp, const char *path, bool
> recurse)
> {
> - return create_or_remove_cgroup(true, mp, path);
> + return create_or_remove_cgroup(true, mp, path, recurse);
> }
>
> char *cgroup_to_absolute_path(struct cgroup_mount_point *mp, const char
> *path, const char *suffix)
> --
> 1.8.5.2
>
> _______________________________________________
> lxc-devel mailing list
> lxc-devel@lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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