[CRIU] [PATCH] libcriu: add CRIU_COMM_BIN mode

Ruslan Kuprieiev kupruser at gmail.com
Thu Jul 23 05:23:07 PDT 2015


Ok

On 07/23/2015 03:21 PM, Pavel Emelyanov wrote:
> On 07/19/2015 05:20 AM, Ruslan Kuprieiev wrote:
>> In this mode libcriu will execute criu binary in swrk
>> mode, so users are not always obliged to run criu service
>> daemon.
> Sorry for late response. The patch looks OK, please do two things.
>
> 1. Split into two -- 1) move code from criu_local_restore_child()
>     into helpers swrk_connect() and swrk_wait() and 2) the rest.
>
> 2. Do s/_bin/_binary/
>
> Thanks
>
>> Signed-off-by: Ruslan Kuprieiev <kupruser at gmail.com>
>> ---
>>   lib/criu.c | 153 ++++++++++++++++++++++++++++++++++++++++++++-----------------
>>   lib/criu.h |   7 ++-
>>   2 files changed, 117 insertions(+), 43 deletions(-)
>>
>> diff --git a/lib/criu.c b/lib/criu.c
>> index da6288a..8008981 100644
>> --- a/lib/criu.c
>> +++ b/lib/criu.c
>> @@ -16,6 +16,8 @@
>>   #include "criu.h"
>>   #include "cr-service-const.h"
>>   
>> +#define CR_DEFAULT_SERVICE_BIN "criu"
>> +
>>   const char *criu_lib_version = CRIU_VERSION;
>>   
>>   static criu_opts *global_opts;
>> @@ -54,6 +56,19 @@ void criu_set_service_fd(int fd)
>>   	criu_local_set_service_fd(global_opts, fd);
>>   }
>>   
>> +void criu_local_set_service_bin(criu_opts *opts, char *path)
>> +{
>> +	if (path)
>> +		opts->service_bin = path;
>> +	else
>> +		opts->service_bin = CR_DEFAULT_SERVICE_BIN;
>> +}
>> +
>> +void criu_set_service_bin(char *path)
>> +{
>> +	criu_local_set_service_bin(global_opts, path);
>> +}
>> +
>>   int criu_local_init_opts(criu_opts **o)
>>   {
>>   	criu_opts *opts = NULL;
>> @@ -663,6 +678,63 @@ static int send_notify_ack(int socket_fd, int ret)
>>   	return ret ? : send_ret;
>>   }
>>   
>> +static int swrk_connect(criu_opts *opts)
>> +{
>> +	int pid;
>> +	int sks[2];
>> +
>> +	if (socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sks)) {
>> +		perror("Failed to create socket pair");
>> +		return -1;
>> +	}
>> +
>> +	/*
>> +	 * Can't setup a SIGCHLD handler here, as it
>> +	 * would alter signal handlers of the caller.
>> +	 */
>> +
>> +	pid = fork();
>> +	if (pid < 0) {
>> +		perror("Failed to fork");
>> +		return -1;
>> +	}
>> +
>> +	if (pid == 0) {
>> +		sigset_t mask;
>> +		char fds[11];
>> +
>> +		/*
>> +		 * Unblock SIGCHLD.
>> +		 *
>> +		 * The caller of this function is supposed to have
>> +		 * this signal blocked. Otherwise it risks to get
>> +		 * into situation, when this routine is not yet
>> +		 * returned, but the restore subtree exits and
>> +		 * emits the SIGCHLD.
>> +		 *
>> +		 * In turn, unblocked SIGCHLD is required to make
>> +		 * criu restoration process work -- it catches
>> +		 * subtasks restore errors in this handler.
>> +		 */
>> +
>> +		sigemptyset(&mask);
>> +		sigaddset(&mask, SIGCHLD);
>> +		sigprocmask(SIG_UNBLOCK, &mask, NULL);
>> +
>> +		close(sks[0]);
>> +		sprintf(fds, "%d", sks[1]);
>> +
>> +		execlp(opts->service_bin, opts->service_bin, "swrk", fds, NULL);
>> +		perror("Can't exec criu swrk");
>> +		exit(1);
>> +	}
>> +
>> +	close(sks[1]);
>> +	opts->swrk_pid = pid;
>> +
>> +	return sks[0];
>> +}
>> +
>>   static int criu_connect(criu_opts *opts)
>>   {
>>   	int fd, ret;
>> @@ -671,6 +743,8 @@ static int criu_connect(criu_opts *opts)
>>   
>>   	if (opts->service_comm == CRIU_COMM_FD)
>>   		return opts->service_fd;
>> +	else if (opts->service_comm == CRIU_COMM_BIN)
>> +		return swrk_connect(opts);
>>   
>>   	fd = socket(AF_LOCAL, SOCK_SEQPACKET, 0);
>>   	if (fd < 0) {
>> @@ -759,6 +833,11 @@ static int send_req_and_recv_resp(criu_opts *opts, CriuReq *req, CriuResp **resp
>>   	return ret;
>>   }
>>   
>> +static void swrk_wait(criu_opts *opts)
>> +{
>> +	waitpid(opts->swrk_pid, NULL, 0);
>> +}
>> +
>>   int criu_local_check(criu_opts *opts)
>>   {
>>   	int ret = -1;
>> @@ -779,6 +858,8 @@ exit:
>>   	if (resp)
>>   		criu_resp__free_unpacked(resp, NULL);
>>   
>> +	swrk_wait(opts);
>> +
>>   	errno = saved_errno;
>>   
>>   	return ret;
>> @@ -816,6 +897,8 @@ exit:
>>   	if (resp)
>>   		criu_resp__free_unpacked(resp, NULL);
>>   
>> +	swrk_wait(opts);
>> +
>>   	errno = saved_errno;
>>   
>>   	return ret;
>> @@ -885,6 +968,8 @@ exit:
>>   	if (resp)
>>   		criu_resp__free_unpacked(resp, NULL);
>>   
>> +	swrk_wait(opts);
>> +
>>   	errno = saved_errno;
>>   
>>   	return ret;
>> @@ -919,6 +1004,8 @@ exit:
>>   	if (resp)
>>   		criu_resp__free_unpacked(resp, NULL);
>>   
>> +	swrk_wait(opts);
>> +
>>   	errno = saved_errno;
>>   
>>   	return ret;
>> @@ -931,59 +1018,44 @@ int criu_restore(void)
>>   
>>   int criu_local_restore_child(criu_opts *opts)
>>   {
>> -	int sks[2], pid, ret = -1;
>> +	int fd, ret = -1;
>> +	enum criu_service_comm saved_comm;
>> +	char *saved_comm_data;
>> +	bool save_comm;
>>   	CriuReq req	= CRIU_REQ__INIT;
>>   	CriuResp *resp	= NULL;
>>   
>> -	if (socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sks))
>> -		goto out;
>> -
>> -	pid = fork();
>> -	if (pid < 0)
>> -		goto err;
>> -
>> -	if (pid == 0) {
>> -		sigset_t mask;
>> -		char fds[11];
>> +	saved_errno = 0;
>>   
>> -		/*
>> -		 * Unblock SIGCHLD.
>> -		 *
>> -		 * The caller of this function is supposed to have
>> -		 * this signal blocked. Otherwise it risks to get
>> -		 * into situation, when this routine is not yet
>> -		 * returned, but the restore subtree exits and
>> -		 * emits the SIGCHLD.
>> -		 *
>> -		 * In turn, unblocked SIGCHLD is required to make
>> -		 * criu restoration process work -- it catches
>> -		 * subtasks restore errors in this handler.
>> -		 */
>> +	save_comm = opts->service_comm != CRIU_COMM_BIN;
>> +	if (save_comm) {
>> +		/* Save comm data */
>> +		saved_comm = opts->service_comm;
>> +		saved_comm_data = opts->service_address;
>>   
>> -		sigemptyset(&mask);
>> -		sigaddset(&mask, SIGCHLD);
>> -		sigprocmask(SIG_UNBLOCK, &mask, NULL);
>> +		opts->service_comm = CRIU_COMM_BIN;
>> +		opts->service_bin = CR_DEFAULT_SERVICE_BIN;
>> +	}
>>   
>> -		close(sks[0]);
>> -		sprintf(fds, "%d", sks[1]);
>> +	fd = swrk_connect(opts);
>> +	if (fd < 0)
>> +		goto out;
>>   
>> -		execlp("criu", "criu", "swrk", fds, NULL);
>> -		perror("Can't exec criu swrk");
>> -		exit(1);
>> +	if (save_comm) {
>> +		/* Restore comm data */
>> +		opts->service_comm = saved_comm;
>> +		opts->service_address = saved_comm_data;
>>   	}
>>   
>> -	close(sks[1]);
>> -
>>   	req.type	= CRIU_REQ_TYPE__RESTORE;
>>   	req.opts	= opts->rpc;
>>   
>>   	req.opts->has_rst_sibling = true;
>>   	req.opts->rst_sibling = true;
>>   
>> -	ret = send_req_and_recv_resp_sk(sks[0], opts, &req, &resp);
>> +	ret = send_req_and_recv_resp_sk(fd, opts, &req, &resp);
>>   
>> -	close(sks[0]);
>> -	waitpid(pid, NULL, 0);
>> +	swrk_wait(opts);
>>   
>>   	if (!ret) {
>>   		ret = resp->success ? resp->restore->pid : -EBADE;
>> @@ -991,12 +1063,9 @@ int criu_local_restore_child(criu_opts *opts)
>>   	}
>>   
>>   out:
>> -	return ret;
>> +	errno = saved_errno;
>>   
>> -err:
>> -	close(sks[1]);
>> -	close(sks[0]);
>> -	goto out;
>> +	return ret;
>>   }
>>   
>>   int criu_restore_child(void)
>> diff --git a/lib/criu.h b/lib/criu.h
>> index 81d3396..ef3a886 100644
>> --- a/lib/criu.h
>> +++ b/lib/criu.h
>> @@ -23,11 +23,13 @@
>>   
>>   enum criu_service_comm {
>>   	CRIU_COMM_SK,
>> -	CRIU_COMM_FD
>> +	CRIU_COMM_FD,
>> +	CRIU_COMM_BIN
>>   };
>>   
>>   void criu_set_service_address(char *path);
>>   void criu_set_service_fd(int fd);
>> +void criu_set_service_bin(char *path);
>>   
>>   /*
>>    * You can choose if you want libcriu to connect to service socket
>> @@ -141,13 +143,16 @@ typedef struct {
>>   	union {
>>   		char		*service_address;
>>   		int		service_fd;
>> +		char		*service_bin;
>>   	};
>> +	int			swrk_pid;
>>   } criu_opts;
>>   
>>   int criu_local_init_opts(criu_opts **opts);
>>   
>>   void criu_local_set_service_address(criu_opts *opts, char *path);
>>   void criu_local_set_service_fd(criu_opts *opts, int fd);
>> +void criu_local_set_service_bin(criu_opts *opts, char *path);
>>   void criu_local_set_service_comm(criu_opts *opts, enum criu_service_comm);
>>   
>>   void criu_local_set_service_fd(criu_opts *opts, int fd);
>>



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