Dan Smith wrote:
> This patch adds a "phase" of checkpoint that saves out information about any
> namespaces the task(s) may have. Do this by tracking the nsproxy of the
> first task and making sure that the tasks that follow get hooked back to
> share the same one on restart.
>
> Restart is handled in userspace by reading the UTS record(s), calling
> unshare() and setting the hostname accordingly. See my changes to
> mktree.c for details.
>
> I tested this with single and multiple task restore, on top of Oren's
> v13 tree.
Thanks, Dan.
[..]
> diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
> index 64155de..12eb1d5 100644
> --- a/checkpoint/checkpoint.c
> +++ b/checkpoint/checkpoint.c
> @@ -193,6 +193,82 @@ static int cr_write_tail(struct cr_ctx *ctx)
> return ret;
> }
>
> +static int cr_write_ns_uts(struct cr_ctx *ctx, struct task_struct *t)
> +{
> + struct cr_hdr h;
> + struct cr_hdr_utsns *hh = cr_hbuf_get(ctx, sizeof(*hh));
> + struct new_utsname *n = &t->nsproxy->uts_ns->name;
> + int ret;
> +
> + h.type = CR_HDR_UTSNS;
> + h.len = sizeof(*hh);
> + h.parent = 0;
> +
> + memcpy(hh->nodename, n->nodename, sizeof(n->nodename));
> + memcpy(hh->domainname, n->domainname, sizeof(n->domainname));
> +
The length of ->nodename etc may change in the future. It's probably
safer to also add the length of the field as well (see for instance
how task->comm is saved).
> + ret = cr_write_obj(ctx, &h, hh);
> + cr_hbuf_put(ctx, sizeof(*hh));
> +
> + return ret;
> +}
[...]
> @@ -156,4 +158,17 @@ struct cr_hdr_fd_data {
> __u64 f_version;
> } __attribute__((aligned(8)));
>
> +#define CR_NSP_UTS 1
> +
> +struct cr_hdr_nsproxy {
> + __u32 objref;
> + __u32 types;
> +};
> +
> +struct cr_hdr_utsns {
> + /* Both of these fields are defined as 65-chars long */
> + char nodename[__NEW_UTS_LEN+1];
> + char domainname[__NEW_UTS_LEN+1];
> +};
add ?
__u16 nodename_len;
__u16 domainname_len;
> +
> #endif /* _CHECKPOINT_CKPT_HDR_H_ */
Oren.
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