[CRIU] [PATCH] libcriu: add CRIU_COMM_BIN mode

Pavel Emelyanov xemul at parallels.com
Thu Jul 23 05:21:33 PDT 2015


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);
> 



More information about the CRIU mailing list