On Wed, 13.05.15 15:45, Iago López Galeiras (i...@endocode.com) wrote:
> If a symlink to a combined cgroup hierarchy already exists and points to
> the right path, skip it. This avoids an error when the cgroups are set
> manually before calling nspawn.
Thanks! Applied with some minor modifications.
> ---
> src/nspawn/nspawn.c | 10 ++++++++--
> src/shared/util.c | 23 +++++++++++++++++++++++
> src/shared/util.h | 1 +
> 3 files changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
> index f292c63..e9e703f 100644
> --- a/src/nspawn/nspawn.c
> +++ b/src/nspawn/nspawn.c
> @@ -1365,8 +1365,14 @@ static int mount_cgroup(const char *dest) {
> if (r < 0)
> return r;
>
> - if (symlink(combined, target) < 0)
> - return log_error_errno(errno, "Failed to
> create symlink for combined hierarchy: %m");
> + r = symlink_idempotent(combined, target);
> + if (r < 0) {
> + if (r == -EINVAL) {
> + log_error("Invalid existing symlink
> for combined hierarchy");
> + return r;
> + } else
> + return log_error_errno(r, "Failed to
> create symlink for combined hierarchy: %m");
> + }
> }
> }
>
> diff --git a/src/shared/util.c b/src/shared/util.c
> index 466dce4..22e00a6 100644
> --- a/src/shared/util.c
> +++ b/src/shared/util.c
> @@ -2765,6 +2765,29 @@ int symlink_atomic(const char *from, const char *to) {
> return 0;
> }
>
> +int symlink_idempotent(const char *from, const char *to) {
> + _cleanup_free_ char *p = NULL;
> + int r;
> +
> + assert(from);
> + assert(to);
> +
> + if (symlink(from, to) < 0) {
> + if (errno == EEXIST) {
> + r = readlink_malloc(to, &p);
> + if (r < 0)
> + return r;
> +
> + if (!streq(p, from)) {
> + return -EINVAL;
> + }
> + } else
> + return -errno;
> + }
> +
> + return 0;
> +}
> +
> int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
> _cleanup_free_ char *t = NULL;
> int r;
> diff --git a/src/shared/util.h b/src/shared/util.h
> index 4a67d5c..8565fd6 100644
> --- a/src/shared/util.h
> +++ b/src/shared/util.h
> @@ -404,6 +404,7 @@ bool machine_name_is_valid(const char *s) _pure_;
>
> char* strshorten(char *s, size_t l);
>
> +int symlink_idempotent(const char *from, const char *to);
>
> int symlink_atomic(const char *from, const char *to);
> int mknod_atomic(const char *path, mode_t mode, dev_t dev);
> --
> 2.4.0
>
> _______________________________________________
> systemd-devel mailing list
> systemd-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Lennart
--
Lennart Poettering, Red Hat
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