[CRIU] [PATCH 2/3] dump: add root_only option

[Ruslan Kuprieiev]

Oh, i totally forgot about it. Sure, I'll send a new patch soon. Thanks.


On 01/10/2017 02:54 PM, Pavel Emelyanov wrote:
> On 01/05/2017 03:42 PM, Ruslan Kuprieiev wrote:
>> This option allows to dump only root of a specified process
>> tree. This behaviour is useful for dumping master processes,
>> that fork it's children to do the work. I.e. one of such cases
>> is php process that forks workers. When one uses this option,
>> he agrees to possible consequences and is ready to handle
>> recovering from such restore on a dumpee side.
> We've had -p|--pid option for the same. If you look at crtools.c
> code there are still trances of it :) Now it's obsoleted, but
> since you need this functionality, let's resurrect one.
>
>> Signed-off-by: Ruslan Kuprieiev <rkuprieiev at cloudlinux.com>
>> ---
>>   criu/cr-service.c         |  3 +++
>>   criu/crtools.c            |  5 +++++
>>   criu/include/cr_options.h |  1 +
>>   criu/seize.c              | 10 ++++++----
>>   images/rpc.proto          |  1 +
>>   lib/c/criu.c              | 11 +++++++++++
>>   lib/c/criu.h              |  2 ++
>>   7 files changed, 29 insertions(+), 4 deletions(-)
>>
>> diff --git a/criu/cr-service.c b/criu/cr-service.c
>> index 00a2d07..721217c 100644
>> --- a/criu/cr-service.c
>> +++ b/criu/cr-service.c
>> @@ -504,6 +504,9 @@ static int setup_opts_from_req(int sk, CriuOpts *req)
>>   		}
>>   	}
>>   
>> +	if (req->has_root_only)
>> +		opts.root_only = req->root_only;
>> +
>>   	if (check_namespace_opts())
>>   		goto err;
>>   
>> diff --git a/criu/crtools.c b/criu/crtools.c
>> index 06b2fa7..61a774c 100644
>> --- a/criu/crtools.c
>> +++ b/criu/crtools.c
>> @@ -286,6 +286,7 @@ int main(int argc, char *argv[], char *envp[])
>>   		{ "check-only",			no_argument,		0, 1085 },
>>   		{ "display-stats",		no_argument,		0, 1086 },
>>   		{ "weak-sysctls",		no_argument,		0, 1087 },
>> +		{ "root-only",			no_argument,		0, 1088 },
>>   		{ },
>>   	};
>>   
>> @@ -613,6 +614,9 @@ int main(int argc, char *argv[], char *envp[])
>>   			pr_msg("Will skip non-existant sysctls on restore\n");
>>   			opts.weak_sysctls = true;
>>   			break;
>> +		case 1088:
>> +			opts.root_only = true;
>> +			break;
>>   		case 'V':
>>   			pr_msg("Version: %s\n", CRIU_VERSION);
>>   			if (strcmp(CRIU_GITID, "0"))
>> @@ -847,6 +851,7 @@ usage:
>>   "  --check-only          check if checkpointing/restoring will actually work\n"
>>   "                        the process will keep on running and memory pages\n"
>>   "                        will not be dumped\n"
>> +"  --root-only           dump only root task in a specified process tree\n"
>>   "\n"
>>   "* External resources support:\n"
>>   "  --external RES        dump objects from this list as external resources:\n"
>> diff --git a/criu/include/cr_options.h b/criu/include/cr_options.h
>> index 4f70b41..3e6e49f 100644
>> --- a/criu/include/cr_options.h
>> +++ b/criu/include/cr_options.h
>> @@ -119,6 +119,7 @@ struct cr_options {
>>   	bool			display_stats;
>>   	bool			weak_sysctls;
>>   	bool			check_only;
>> +	bool			root_only;
>>   };
>>   
>>   extern struct cr_options opts;
>> diff --git a/criu/seize.c b/criu/seize.c
>> index a1cf497..c67f9a3 100644
>> --- a/criu/seize.c
>> +++ b/criu/seize.c
>> @@ -805,10 +805,12 @@ static int collect_task(struct pstree_item *item)
>>   	if (ret < 0)
>>   		goto err_close;
>>   
>> -	/* Depth-first search (DFS) is used for traversing a process tree. */
>> -	ret = collect_loop(item, collect_children);
>> -	if (ret < 0)
>> -		goto err_close;
>> +	if (!opts.root_only) {
>> +		/* Depth-first search (DFS) is used for traversing a process tree. */
>> +		ret = collect_loop(item, collect_children);
>> +		if (ret < 0)
>> +			goto err_close;
>> +	}
>>   
>>   	if ((item->pid.state == TASK_DEAD) && !list_empty(&item->children)) {
>>   		pr_err("Zombie with children?! O_o Run, run, run!\n");
>> diff --git a/images/rpc.proto b/images/rpc.proto
>> index 7cf958c..42052c9 100644
>> --- a/images/rpc.proto
>> +++ b/images/rpc.proto
>> @@ -108,6 +108,7 @@ message criu_opts {
>>   	optional uint32			timeout			= 45;
>>   	optional bool			tcp_skip_in_flight	= 46;
>>   	optional bool			weak_sysctls		= 47;
>> +	optional bool			root_only		= 48;
>>   }
>>   
>>   message criu_dump_resp {
>> diff --git a/lib/c/criu.c b/lib/c/criu.c
>> index 08806c6..4730506 100644
>> --- a/lib/c/criu.c
>> +++ b/lib/c/criu.c
>> @@ -880,6 +880,17 @@ int criu_add_external(char *key)
>>   	return criu_local_add_external(global_opts, key);
>>   }
>>   
>> +void criu_local_set_root_only(criu_opts *opts, bool root_only)
>> +{
>> +	opts->rpc->has_root_only = true;
>> +	opts->rpc->root_only = root_only;
>> +}
>> +
>> +void criu_set_root_only(bool root_only)
>> +{
>> +	criu_local_set_root_only(global_opts, root_only);
>> +}
>> +
>>   static CriuResp *recv_resp(int socket_fd)
>>   {
>>   	unsigned char *buf = NULL;
>> diff --git a/lib/c/criu.h b/lib/c/criu.h
>> index 5d0b5b6..9928d1d 100644
>> --- a/lib/c/criu.h
>> +++ b/lib/c/criu.h
>> @@ -95,6 +95,7 @@ void criu_set_ghost_limit(unsigned int limit);
>>   int criu_add_irmap_path(char *path);
>>   int criu_add_inherit_fd(int fd, char *key);
>>   int criu_add_external(char *key);
>> +void criu_set_root_only(bool root_only);
>>   
>>   /*
>>    * The criu_notify_arg_t na argument is an opaque
>> @@ -206,6 +207,7 @@ int criu_local_add_cg_props_file(criu_opts *opts, char *path);
>>   int criu_local_add_cg_dump_controller(criu_opts *opts, char *name);
>>   int criu_local_add_inherit_fd(criu_opts *opts, int fd, char *key);
>>   int criu_local_add_external(criu_opts *opts, char *key);
>> +void criu_local_set_root_only(criu_opts *opts, bool root_only);
>>   
>>   void criu_local_set_notify_cb(criu_opts *opts, int (*cb)(char *action, criu_notify_arg_t na));
>>   
>>