[CRIU] [PATCHv3 4/4] crtools: cr_service() and fixes for it

Ruslan Kuprieiev kupruser at gmail.com
Mon Sep 2 11:18:08 EDT 2013


On 09/02/2013 07:15 PM, Ruslan Kuprieiev wrote:
> cr_service() is function to start daemon, that will create unix domain 
> socket and will listen for requests from libcriu on it. If request is 
> obtained, it will fork() child, that will recv, process arguments and 
> dump program.
>
> P.S. scripts/checkpatch.pl reports a warning "quoted string split 
> across lines" on this:
> pr_perror("Looks like criu (version %s) is out-of-date. "
>                 "Please, upgrade criu.", version);
> What is the problem here?
>
> P.P.S.I googled and still don't get what is wrong.Sorry for stupid 
> questions, i'm noob.

-------------- next part --------------
diff --git a/cr-service.c b/cr-service.c
index e921828..6a79cdd 100644
--- a/cr-service.c
+++ b/cr-service.c
@@ -1,4 +1,251 @@
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+
+#include "crtools.h"
+#include "util-pie.h"
+#include "log.h"
+#include "libcriu.h"
+#include "version.h"
+#include "protobuf/criu-dump-args.pb-c.h"
+
+
+static CriuDumpArgs *args;
+static int client_fd;
+
+static int criu_recv_dump_args(int socket_fd)
+{
+	int len;
+	unsigned char *buf;
+	/*
+	 * Recv the size of args and then
+	 * recv args.
+	 */
+	if (recv(socket_fd, &len, sizeof(len), 0) == -1) {
+		pr_perror("Can't recv size of args");
+		return -1;
+	}
+
+	buf = malloc(len);
+	if (buf == NULL) {
+		pr_perror("Can't allocate memory");
+		return -1;
+	}
+
+	errno = 0;
+	if (recv(socket_fd, buf, len, MSG_WAITALL) == -1) {
+		if (errno == EAGAIN || errno == EWOULDBLOCK)
+			pr_perror("Recv timeout");
+		pr_perror("Can't recv args");
+		return -1;
+	}
+
+	args = criu_dump_args__unpack(NULL, len, buf);
+	if (args == NULL) {
+		pr_perror("Can't unpack msg");
+		return -1;
+	}
+
+	/*
+	 * Recv opened dir fd, where to put images
+	 */
+	args->images_dir_fd = recv_fd(socket_fd);
+	if (args->images_dir_fd == -1) {
+		pr_perror("Can't recv file descriptor");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * This function is needed in sk-unix.c,
+ * to recognize connection to service socket
+ * and dump it properly.
+ */
+int get_lib_sk_ino(void)
+{
+	struct stat st;
+
+	if (fstat(client_fd, &st)) {
+		pr_perror("Can't get library socket stat");
+		return -1;
+	}
+
+	return st.st_ino;
+}
+
+static int get_client_pid(void)
+{
+	struct ucred ids;
+	socklen_t ids_len;
+	ids_len = sizeof(struct ucred);
+
+	if (getsockopt(client_fd, SOL_SOCKET, SO_PEERCRED, &ids, &ids_len)) {
+		pr_perror("Can't get socket options.");
+		return -1;
+	}
+
+	return ids.pid;
+}
+
+static int child_work(void)
+{
+	int pid;
+	int ret;
+
+	if (criu_recv_dump_args(client_fd) == -1) {
+		pr_perror("Can't recv args");
+		goto child_err;
+	}
+
+	/* check version */
+	if (args->version_major != CRIU_VERSION_MAJOR ||
+	    args->version_minor != CRIU_VERSION_MINOR) {
+		pr_perror("Looks like criu (version %s) is out-of-date. "
+			  "Please, upgrade criu.", version);
+		ret = CRIU_OLD_VERSION;
+		goto child_out;
+	}
+
+	pid = get_client_pid();
+	if (pid == -1) {
+		pr_perror("Can't get pid");
+		goto child_err;
+	}
+
+	/* going to dir, where to place images*/
+	if (fchdir(args->images_dir_fd)) {
+		pr_perror("Can't change directory.");
+		goto child_err;
+	}
+
+	/* initiate log file in imgs dir */
+	opts.output = malloc(sizeof(char)*PATH_MAX);
+	strcpy(opts.output, getcwd(NULL, PATH_MAX));
+	strcat(opts.output, "/dump.log");
+
+	if (open_image_dir() < 0) {
+		pr_perror("Can't open current directory.");
+		goto child_err;
+	}
+
+	/* FIXME: log level of dump.log is the same as log level,
+	 * which was set when running criu service. Add log level
+	 * to args.
+	 */
+	if (log_init(opts.output) == -1) {
+		pr_perror("Can't initiate log.");
+		goto child_err;
+	}
+
+	/* checking dump flags from client */
+	if (args->flags & CRIU_DUMP_AND_CONTINUE) {
+		opts.final_state = TASK_ALIVE;
+		ret = CRIU_DUMP_SUCCESS; /* pre set */
+	}
+
+	/* dump */
+	if (cr_dump_tasks(pid) < 0) {
+		pr_perror("Dump failed.");
+		goto child_err;
+	}
+
+	close(client_fd);
+	exit(0);
+
+child_err:
+	ret = CRIU_DUMP_FAIL;
+child_out:
+	if (send(client_fd, &ret, sizeof(ret), 0) == -1)
+		pr_perror("Can't send msg to lib");
+
+	close(client_fd);
+	exit(1);
+}
+
 int cr_service(void)
 {
+	int server_fd;
+	int child_pid;
+	struct sockaddr_un server_addr;
+	struct sockaddr_un client_addr;
+	socklen_t server_addr_len;
+	socklen_t client_addr_len;
+
+	server_fd = socket(AF_LOCAL, SOCK_STREAM, 0);
+	if (server_fd == -1) {
+		pr_perror("Can't initialize service socket.");
+		return -1;
+	}
+
+	memset(&server_addr, 0, sizeof(server_addr));
+	memset(&client_addr, 0, sizeof(client_addr));
+	server_addr.sun_family = AF_LOCAL;
+
+	if (opts.addr == NULL)
+		opts.addr = CR_DEFAULT_SERVICE_ADDRESS;
+
+	strcpy(server_addr.sun_path, opts.addr);
+
+	server_addr_len = strlen(server_addr.sun_path)
+			+ sizeof(server_addr.sun_family);
+	client_addr_len = sizeof(client_addr);
+
+	unlink(server_addr.sun_path);
+
+	if (bind(server_fd, (struct sockaddr *) &server_addr,
+					server_addr_len) == -1) {
+		pr_perror("Can't bind.");
+		return -1;
+	}
+
+	/* change service socket permissions, so anyone can connect to it */
+	if (chmod(server_addr.sun_path, 0666)) {
+		pr_perror("Can't change permissions of the service socket.");
+		return -1;
+	}
+
+	if (listen(server_fd, 16) == -1) {
+		pr_perror("Can't listen for socket connections.");
+		return -1;
+	}
+
+	/* FIXME Do not ignore children's return values */
+	signal(SIGCHLD, SIG_IGN);
+
+	while (1) {
+		pr_info("Waiting for connection...\n");
+
+		client_fd = accept(server_fd, &client_addr, &client_addr_len);
+		if (client_fd == -1) {
+			pr_perror("Can't accept connection.");
+			continue;
+		}
+
+		pr_info("Connected.\n");
+
+		switch (child_pid = fork()) {
+		case -1:
+			pr_perror("Can't fork a child.");
+			continue;
+		case 0:
+			exit(child_work());
+		default:
+			close(client_fd);
+		}
+	}
+
 	return 0;
 }
diff --git a/include/crtools.h b/include/crtools.h
index d867522..ce7466d 100644
--- a/include/crtools.h
+++ b/include/crtools.h
@@ -121,6 +121,8 @@ int cr_check(void);
 int cr_exec(int pid, char **opts);
 int cr_service(void);
 
+int get_lib_sk_ino(void);
+
 #define O_DUMP	(O_RDWR | O_CREAT | O_EXCL)
 #define O_SHOW	(O_RDONLY)
 #define O_RSTR	(O_RDONLY)
diff --git a/include/image.h b/include/image.h
index 5cd7741..b201226 100644
--- a/include/image.h
+++ b/include/image.h
@@ -18,6 +18,7 @@
 #define REMAP_GHOST	(1 << 31)
 
 #define USK_EXTERN	(1 << 0)
+#define USK_LIB_CTRL	(1 << 1)
 
 #define VMA_AREA_NONE		(0 <<  0)
 #define VMA_AREA_REGULAR	(1 <<  0)	/* Dumpable area */
diff --git a/sk-unix.c b/sk-unix.c
index cf024a5..365c5ac 100644
--- a/sk-unix.c
+++ b/sk-unix.c
@@ -21,6 +21,7 @@
 #include "sockets.h"
 #include "sk-queue.h"
 #include "mount.h"
+#include "libcriu.h"
 
 #include "protobuf.h"
 #include "protobuf/sk-unix.pb-c.h"
@@ -138,6 +139,17 @@ static int dump_one_unix_fd(int lfd, u32 id, const struct fd_parms *p)
 	ue.opts		= &skopts;
 	ue.uflags	= 0;
 
+	/*
+	 * Check if this is library socket,
+	 * that is connected to criu service.
+	 * Dump it like closed one and mark it for restore.
+	 */
+	if (ue.peer == get_lib_sk_ino()) {
+		ue.state = TCP_CLOSE;
+		ue.peer = 0;
+		ue.uflags |= USK_LIB_CTRL;
+	}
+
 	if (sk->namelen && *sk->name) {
 		ue.file_perms = &perms;
 
@@ -716,7 +728,23 @@ static int open_unixsk_standalone(struct unix_sk_info *ui)
 	pr_info("Opening standalone socket (id %#x ino %#x peer %#x)\n",
 			ui->ue->id, ui->ue->ino, ui->ue->peer);
 
-	if ((ui->ue->state == TCP_ESTABLISHED) && !ui->ue->peer) {
+	if (ui->ue->uflags & USK_LIB_CTRL) {
+		int sks[2];
+
+		if (socketpair(PF_UNIX, ui->ue->type, 0, sks)) {
+			pr_perror("Can't create socketpair");
+			return -1;
+		}
+
+		int msg = CRIU_RESUME;
+		if (write(sks[1], &msg, sizeof(msg)) != sizeof(msg)) {
+			pr_perror("Can't write msg for lib to socket");
+			return -1;
+		}
+
+		close(sks[1]);
+		sk = sks[0];
+	} else if ((ui->ue->state == TCP_ESTABLISHED) && !ui->ue->peer) {
 		int ret, sks[2];
 
 		if (ui->ue->type != SOCK_STREAM) {


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