[CRIU] [PATCH 3/3] unix: allow --external unix[ino]:string

[Pavel Emelyanov]

On 01/05/2017 03:42 PM, Ruslan Kuprieiev wrote:

Can you elaborate what this option should do? It's not 100% clear
from the code.

> Needles to say that it's useful for debug, but this is also
> very useful when you syncronise checkpoint/restore whith a
> dumpee using unix socketpair and want it to painlessly
> receive notification on restore.
> 
> Signed-off-by: Ruslan Kuprieiev <rkuprieiev at cloudlinux.com>
> ---
>  criu/sk-unix.c       | 23 +++++++++++++++++++++--
>  images/sk-unix.proto |  5 +++++
>  2 files changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/criu/sk-unix.c b/criu/sk-unix.c
> index 5cbe07a..4527dd6 100644
> --- a/criu/sk-unix.c
> +++ b/criu/sk-unix.c
> @@ -263,6 +263,8 @@ static int dump_one_unix_fd(int lfd, u32 id, const struct fd_parms *p)
>  	SkOptsEntry *skopts;
>  	FilePermsEntry *perms;
>  	FownEntry *fown;
> +	char buf[PATH_MAX];
> +	char *ext = NULL;
>  
>  	ue = xmalloc(sizeof(UnixSkEntry) +
>  			sizeof(SkOptsEntry) +
> @@ -322,6 +324,16 @@ static int dump_one_unix_fd(int lfd, u32 id, const struct fd_parms *p)
>  		ue->uflags |= USK_SERVICE;
>  	}
>  
> +	/* Same as with service_sk, but for custom sockets */
> +	snprintf(buf, sizeof(buf), "unix[%u]", ue->peer);
> +	ext = external_lookup_by_key(buf);
> +	if (unlikely(!IS_ERR_OR_NULL(ext))) {
> +		ue->state = TCP_CLOSE;
> +		ue->peer = 0;
> +		ue->uflags |= USK_SERVICE;
> +		ue->stub = (void *)strtok(ext, ":");
> +	}
> +
>  	if (sk->namelen && *sk->name) {
>  		ue->file_perms = perms;
>  
> @@ -1139,8 +1151,15 @@ static int open_unixsk_standalone(struct unix_sk_info *ui)
>  			return -1;
>  		}
>  
> -		if (send_criu_dump_resp(sks[1], true, true) == -1)
> -			return -1;
> +		if (ui->ue->stub) {
> +			unsigned int l;
> +			l = strlen(ui->ue->stub);
> +			if (write(sks[1], ui->ue->stub, l) != l)
> +				return -1;
> +		} else {
> +			if (send_criu_dump_resp(sks[1], true, true) == -1)
> +				return -1;
> +		}
>  
>  		close(sks[1]);
>  		sk = sks[0];
> diff --git a/images/sk-unix.proto b/images/sk-unix.proto
> index 3026214..4437700 100644
> --- a/images/sk-unix.proto
> +++ b/images/sk-unix.proto
> @@ -48,4 +48,9 @@ message unix_sk_entry {
>  	 */
>  	optional string			name_dir	= 14;
>  	optional bool			deleted		= 15;
> +
> +	/*
> +	 * Stub to put into service socket on restore
> +	 */
> +        optional string			stub		= 16;
>  }
>