[CRIU] [PATCH 1/6] lib: add support for --action-script in libcriu

[Pavel Emelyanov]

On 07/29/2014 09:06 PM, Tycho Andersen wrote:

Hi, Tycho!

The issue with action scripts in library is quite nasty.

First of all, when using service, we cannot ask one to call any scripts, since
service is run as root and making it run user-provided code is unsafe. Instead
of doing this we make service respond back via socket when some script should
be called. At that time service waits for the client to do the action and wake
service back. This is what p.haul does and what Andrey pointed out.

As far as the library is concerned -- I had an idea that we could register a
callback, that should be called when the service reports that we have to make
some action, but I haven't tried implementing it yet.

How do you think actions would be suitable for you when used with library?

Thanks,
Pavel

> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
>  cr-service.c       | 15 +++++++++++++++
>  lib/criu.c         | 19 +++++++++++++++++++
>  lib/criu.h         |  1 +
>  protobuf/rpc.proto |  2 ++
>  4 files changed, 37 insertions(+)
> 
> diff --git a/cr-service.c b/cr-service.c
> index 64ce751..11e9778 100644
> --- a/cr-service.c
> +++ b/cr-service.c
> @@ -300,6 +300,21 @@ static int setup_opts_from_req(int sk, CriuOpts *req)
>  			return -1;
>  	}
>  
> +	for (i = 0; i < req->n_action_scripts; i++) {
> +		struct script *script;
> +
> +		script = xmalloc(sizeof(*script));
> +		if(!script)
> +			return -1;
> +
> +		script->path = xstrdup(req->action_scripts[i]);
> +		if (!script->path) {
> +			free(script);
> +			return -1;
> +		}
> +		list_add(&script->node, &opts.scripts);
> +	}
> +
>  	if (req->has_cpu_cap)
>  		opts.cpu_cap = req->cpu_cap;
>  
> diff --git a/lib/criu.c b/lib/criu.c
> index 7c1ac07..9d84c83 100644
> --- a/lib/criu.c
> +++ b/lib/criu.c
> @@ -259,6 +259,25 @@ er:
>  	return -ENOMEM;
>  }
>  
> +int criu_add_action_script(char *script)
> +{
> +	void *m;
> +	opts->n_action_scripts++;
> +	m = realloc(opts->action_scripts, sizeof(char*) * opts->n_action_scripts);
> +	if (!m)
> +		return -1;
> +	opts->action_scripts = m;
> +
> +	m = strdup(script);
> +	opts->action_scripts[opts->n_action_scripts - 1] = m;
> +	if (!m) {
> +		opts->n_action_scripts--;
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
>  static CriuResp *recv_resp(int socket_fd)
>  {
>  	unsigned char buf[CR_MAX_MSG_SIZE];
> diff --git a/lib/criu.h b/lib/criu.h
> index 18faaef..5ab09c3 100644
> --- a/lib/criu.h
> +++ b/lib/criu.h
> @@ -47,6 +47,7 @@ void criu_set_log_level(int log_level);
>  void criu_set_log_file(char *log_file);
>  void criu_set_cpu_cap(unsigned int cap);
>  void criu_set_root(char *root);
> +int criu_add_action_script(char *script);
>  int criu_set_exec_cmd(int argc, char *argv[]);
>  int criu_add_ext_mount(char *key, char *val);
>  int criu_add_veth_pair(char *in, char *out);
> diff --git a/protobuf/rpc.proto b/protobuf/rpc.proto
> index e50d97c..1604f37 100644
> --- a/protobuf/rpc.proto
> +++ b/protobuf/rpc.proto
> @@ -45,6 +45,8 @@ message criu_opts {
>  	repeated string			exec_cmd	= 22;
>  
>  	repeated ext_mount_map		ext_mnt		= 23;
> +
> +	repeated string			action_scripts	= 24;
>  }
>  
>  message criu_dump_resp {
>