[CRIU] [PATCH 2/5] Process Migration using Sockets

[rbruno at gsd.inesc-id.pt]

 criu/sk-queue.c | 33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

    In order to prepare for the use of sockets to transfer the image files
    lseek calls needs to be removed. For sk-queue, we now read the packet
    data at the same time than the header. This has the disadvantage to
    consume more memory between the image read and the packets restore, but
    should hopefully be affordable.

    Signed-off-by: Rodrigo Bruno <rbruno at gsd.inesc-id.pt>
    Signed-off-by: Katerina Koukiou <k.koukiou at gmail.com>

diff --git a/criu/sk-queue.c b/criu/sk-queue.c
index 7b1da2d..f92d020 100644
--- a/criu/sk-queue.c
+++ b/criu/sk-queue.c
@@ -27,7 +27,7 @@
 struct sk_packet {
 	struct list_head	list;
 	SkPacketEntry		*entry;
-	off_t			img_off;
+	char        		*data;
 };

 static LIST_HEAD(packets_list);
@@ -37,14 +37,20 @@ static int collect_one_packet(void *obj,
ProtobufCMessage *msg, struct cr_img *i
 	struct sk_packet *pkt = obj;

 	pkt->entry = pb_msg(msg, SkPacketEntry);
-	pkt->img_off = lseek(img_raw_fd(img), 0, SEEK_CUR);
+
+	pkt->data = xmalloc(pkt->entry->length);
+	if (pkt->data ==NULL)
+		return -1;
+
 	/*
 	 * NOTE: packet must be added to the tail. Otherwise sequence
 	 * will be broken.
 	 */
 	list_add_tail(&pkt->list, &packets_list);
-	if (lseek(img_raw_fd(img), pkt->entry->length, SEEK_CUR) < 0) {
-		pr_perror("Unable to change an image offset");
+
+	if (read_img_buf(img, pkt->data, pkt->entry->length) != 1) {
+		xfree(pkt->data);
+		pr_perror("Unable to read packet data");
 		return -1;
 	}

@@ -208,7 +214,6 @@ int restore_sk_queue(int fd, unsigned int peer_id)

 	list_for_each_entry_safe(pkt, tmp, &packets_list, list) {
 		SkPacketEntry *entry = pkt->entry;
-		char *buf;

 		if (entry->id_for != peer_id)
 			continue;
@@ -224,22 +229,8 @@ int restore_sk_queue(int fd, unsigned int peer_id)
 		 * boundaries messages should be saved.
 		 */

-		buf = xmalloc(entry->length);
-		if (buf ==NULL)
-			goto err;
-
-		if (lseek(img_raw_fd(img), pkt->img_off, SEEK_SET) == -1) {
-			pr_perror("lseek() failed");
-			xfree(buf);
-			goto err;
-		}
-		if (read_img_buf(img, buf, entry->length) != 1) {
-			xfree(buf);
-			goto err;
-		}
-
-		ret = write(fd, buf, entry->length);
-		xfree(buf);
+		ret = write(fd, pkt->data, entry->length);
+		xfree(pkt->data);
 		if (ret < 0) {
 			pr_perror("Failed to send packet");
 			goto err;