[CRIU] [PATCH 2/3] Process Migration using Sockets
Rodrigo Bruno
rbruno at gsd.inesc-id.pt
Wed Jan 11 09:16:16 PST 2017
criu/img-cache.c | 153 +++++++++
criu/img-proxy.c | 89 +++++
criu/img-remote-proto.c | 741
++++++++++++++++++++++++++++++++++++++++
criu/include/img-remote-proto.h | 86 +++++
4 files changed, 1069 insertions(+)
The current patch brings the implementation of the image proxy and
image cache.
These components are necessary to perform in-memory live migration of
processes
using CRIU. The image proxy receives images from CRIU Dump/Pre-Dump
(through
UNIX sockets) and forwards them to the image cache (through a TCP
socket). The
image cache caches image in memory and sends them to CRIU Restore
(through
UNIX sockets) when requested.
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/img-cache.c b/criu/img-cache.c
new file mode 100644
index 0000000..9111fbd
--- /dev/null
+++ b/criu/img-cache.c
@@ -0,0 +1,153 @@
+#include <unistd.h>
+
+#include "img-remote-proto.h"
+#include "criu-log.h"
+#include <pthread.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <fcntl.h>
+#include "cr_options.h"
+
+static struct rimage *wait_for_image(struct wthread *wt)
+{
+ struct rimage *result;
+
+ if (!strncmp(wt->path, RESTORE_FINISH, sizeof(RESTORE_FINISH))) {
+ finished = true;
+ shutdown(local_req_fd, SHUT_RD);
+ return NULL;
+ }
+
+ result = get_rimg_by_name(wt->snapshot_id, wt->path);
+ if (result != NULL && result->size > 0)
+ return result;
+
+ /* The file does not exist and we do not expect new files */
+ if (finished && !is_receiving())
+ return NULL;
+
+ /* NOTE: at this point, when the thread wakes up, either the image is
+ * already in memory or it will never come (the dump is finished).
+ */
+ sem_wait(&(wt->wakeup_sem));
+ result = get_rimg_by_name(wt->snapshot_id, wt->path);
+ if (result != NULL && result->size > 0)
+ return result;
+ else
+ return NULL;
+}
+
+/* The image cache creates a thread that calls this function. It waits for
remote
+ * images from the image-cache.
+ */
+void *accept_remote_image_connections(void *port)
+{
+ int fd = *((int *) port);
+ struct sockaddr_in cli_addr;
+ socklen_t clilen = sizeof(cli_addr);
+ char snapshot_id_buf[PATHLEN], path_buf[PATHLEN];
+ uint64_t size, ret;
+ int flags, proxy_fd;
+ struct rimage *rimg;
+
+ proxy_fd = accept(fd, (struct sockaddr *) &cli_addr, &clilen);
+ if (proxy_fd < 0) {
+ pr_perror("Unable to accept remote image connection from image proxy");
+ return NULL;
+ }
+ while (1) {
+ ret = read_remote_header(proxy_fd, snapshot_id_buf, path_buf, &flags,
&size);
+ if (ret < 0) {
+ pr_perror("Unable to receive remote header from image proxy");
+ return NULL;
+ }
+ /* This means that the no more images are coming. */
+ else if (!ret) {
+ pr_info("Image Proxy connection closed.\n");
+ finished = true;
+ unlock_workers();
+ return NULL;
+ }
+
+ pr_info("Received %s request for %s:%s\n",
+ flags == O_RDONLY ? "read" :
+ flags == O_APPEND ? "append" : "write",
+ path_buf, snapshot_id_buf);
+
+ rimg = prepare_remote_image(path_buf, snapshot_id_buf, flags);
+
+ prepare_recv_rimg();
+ if (!size)
+ ret = 0;
+ else
+ ret = recv_image(proxy_fd, rimg, size, flags, false);
+ if (ret < 0) {
+ pr_perror("Unable to receive %s:%s from image proxy",
+ rimg->path, rimg->snapshot_id);
+ finalize_recv_rimg(NULL);
+ return NULL;
+ } else if (ret != size) {
+ pr_perror("Unable to receive %s:%s from image proxy (received %lu bytes,
expected %lu bytes)",
+ rimg->path, rimg->snapshot_id, ret, size);
+ finalize_recv_rimg(NULL);
+ return NULL;
+ }
+ finalize_recv_rimg(rimg);
+
+ pr_info("Finished receiving %s:%s (received %lu bytes)\n",
+ rimg->path, rimg->snapshot_id, ret);
+ }
+}
+
+int image_cache(bool background, char *local_cache_path, unsigned short
cache_write_port)
+{
+ pthread_t local_req_thr, remote_req_thr;
+
+ pr_info("Proxy to Cache Port %d, CRIU to Cache Path %s\n",
+ cache_write_port, local_cache_path);
+
+
+ if (opts.ps_socket != -1) {
+ proxy_to_cache_fd = opts.ps_socket;
+ pr_info("Re-using ps socket %d\n", proxy_to_cache_fd);
+ } else {
+ proxy_to_cache_fd = setup_TCP_server_socket(cache_write_port);
+ if (proxy_to_cache_fd < 0) {
+ pr_perror("Unable to open proxy to cache TCP socket");
+ return -1;
+ }
+ }
+
+ local_req_fd = setup_UNIX_server_socket(local_cache_path);
+ if (local_req_fd < 0) {
+ pr_perror("Unable to open cache to proxy UNIX socket");
+ return -1;
+ }
+
+ if (init_daemon(background, wait_for_image)) {
+ pr_perror("Unable to initialize daemon");
+ return -1;
+ }
+
+ if (pthread_create(
+ &remote_req_thr,
+ NULL, accept_remote_image_connections,
+ (void *) &proxy_to_cache_fd)) {
+ pr_perror("Unable to create remote requests thread");
+ return -1;
+ }
+ if (pthread_create(
+ &local_req_thr,
+ NULL,
+ accept_local_image_connections,
+ (void *) &local_req_fd)) {
+ pr_perror("Unable to create local requests thread");
+ return -1;
+ }
+
+ pthread_join(remote_req_thr, NULL);
+ pthread_join(local_req_thr, NULL);
+ join_workers();
+ pr_info("Finished image cache.");
+ return 0;
+}
diff --git a/criu/img-proxy.c b/criu/img-proxy.c
new file mode 100644
index 0000000..cb46745
--- /dev/null
+++ b/criu/img-proxy.c
@@ -0,0 +1,89 @@
+#include <unistd.h>
+
+#include "img-remote.h"
+#include "img-remote-proto.h"
+#include "criu-log.h"
+#include <pthread.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include "cr_options.h"
+
+static struct rimage *wait_for_image(struct wthread *wt)
+{
+ return get_rimg_by_name(wt->snapshot_id, wt->path);
+}
+
+uint64_t forward_image(struct rimage *rimg)
+{
+ uint64_t ret;
+ int fd = proxy_to_cache_fd;
+
+ pthread_mutex_lock(&(rimg->in_use));
+ if (write_remote_header(
+ fd, rimg->snapshot_id, rimg->path, O_APPEND, rimg->size) < 0) {
+ pr_perror("Error writing header for %s:%s",
+ rimg->path, rimg->snapshot_id);
+ pthread_mutex_unlock(&(rimg->in_use));
+ return -1;
+ }
+
+ ret = send_image(fd, rimg, O_APPEND, false);
+ if (ret < 0) {
+ pr_perror("Unable to send %s:%s to image cache",
+ rimg->path, rimg->snapshot_id);
+ pthread_mutex_unlock(&(rimg->in_use));
+ return -1;
+ } else if (ret != rimg->size) {
+ pr_perror("Unable to send %s:%s to image proxy (sent %lu bytes, expected
%lu bytes",
+ rimg->path, rimg->snapshot_id, ret, rimg->size);
+ pthread_mutex_unlock(&(rimg->in_use));
+ return -1;
+ }
+ pthread_mutex_unlock(&(rimg->in_use));
+
+ pr_info("Finished forwarding %s:%s (sent %lu bytes)\n",
+ rimg->path, rimg->snapshot_id, rimg->size);
+ return ret;
+}
+
+int image_proxy(bool background, char *local_proxy_path, char *fwd_host,
unsigned short fwd_port)
+{
+ pthread_t local_req_thr;
+
+ pr_info("CRIU to Proxy Path: %s, Cache Address %s:%hu\n",
+ local_proxy_path, fwd_host, fwd_port);
+
+ local_req_fd = setup_UNIX_server_socket(local_proxy_path);
+ if (local_req_fd < 0) {
+ pr_perror("Unable to open CRIU to proxy UNIX socket");
+ return -1;
+ }
+
+ if (opts.ps_socket != -1) {
+ proxy_to_cache_fd = opts.ps_socket;
+ pr_info("Re-using ps socket %d\n", proxy_to_cache_fd);
+ } else {
+ proxy_to_cache_fd = setup_TCP_client_socket(fwd_host, fwd_port);
+ if (proxy_to_cache_fd < 0) {
+ pr_perror("Unable to open proxy to cache TCP socket");
+ return -1;
+ }
+ }
+
+ if (init_daemon(background, wait_for_image))
+ return -1;
+
+ if (pthread_create(
+ &local_req_thr,
+ NULL,
+ accept_local_image_connections,
+ (void *) &local_req_fd)) {
+ pr_perror("Unable to create local requests thread");
+ return -1;
+ }
+
+ pthread_join(local_req_thr, NULL);
+ join_workers();
+ pr_info("Finished image proxy.");
+ return 0;
+}
diff --git a/criu/img-remote-proto.c b/criu/img-remote-proto.c
new file mode 100644
index 0000000..2dcb4ad
--- /dev/null
+++ b/criu/img-remote-proto.c
@@ -0,0 +1,741 @@
+#include <unistd.h>
+#include <stdlib.h>
+
+#include <semaphore.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include "sys/un.h"
+#include <pthread.h>
+#include <fcntl.h>
+#include <sys/file.h>
+
+#include "img-remote-proto.h"
+#include "criu-log.h"
+#include "common/compiler.h"
+
+#include "protobuf.h"
+#include "images/remote-image.pb-c.h"
+#include "image.h"
+
+LIST_HEAD(rimg_head);
+pthread_mutex_t rimg_lock;
+
+pthread_mutex_t proxy_to_cache_lock;
+
+LIST_HEAD(workers_head);
+pthread_mutex_t workers_lock;
+sem_t workers_semph;
+
+struct rimage * (*wait_for_image) (struct wthread *wt);
+
+bool finished = false;
+int writing = 0;
+int forwarding = 0;
+int proxy_to_cache_fd;
+int local_req_fd;
+
+struct rimage *get_rimg_by_name(const char *snapshot_id, const char *path)
+{
+ struct rimage *rimg = NULL;
+
+ pthread_mutex_lock(&rimg_lock);
+ list_for_each_entry(rimg, &rimg_head, l) {
+ if (!strncmp(rimg->path, path, PATHLEN) &&
+ !strncmp(rimg->snapshot_id, snapshot_id, PATHLEN)) {
+ pthread_mutex_unlock(&rimg_lock);
+ return rimg;
+ }
+ }
+ pthread_mutex_unlock(&rimg_lock);
+ return NULL;
+}
+
+static struct wthread *get_wt_by_name(const char *snapshot_id, const char
*path)
+{
+ struct wthread *wt = NULL;
+
+ pthread_mutex_lock(&workers_lock);
+ list_for_each_entry(wt, &workers_head, l) {
+ if (!strncmp(wt->path, path, PATHLEN) &&
+ !strncmp(wt->snapshot_id, snapshot_id, PATHLEN)) {
+ pthread_mutex_unlock(&workers_lock);
+ return wt;
+ }
+ }
+ pthread_mutex_unlock(&workers_lock);
+ return NULL;
+}
+
+static int init_sync_structures(void)
+{
+ if (pthread_mutex_init(&rimg_lock, NULL) != 0) {
+ pr_perror("Remote image list mutex init failed");
+ return -1;
+ }
+
+ if (pthread_mutex_init(&proxy_to_cache_lock, NULL) != 0) {
+ pr_perror("Remote image connection mutex init failed");
+ return -1;
+ }
+
+ if (pthread_mutex_init(&workers_lock, NULL) != 0) {
+ pr_perror("Workers mutex init failed");
+ return -1;
+ }
+
+ if (sem_init(&workers_semph, 0, 0) != 0) {
+ pr_perror("Workers semaphore init failed");
+ return -1;
+ }
+
+ return 0;
+}
+
+void prepare_recv_rimg(void)
+{
+ pthread_mutex_lock(&rimg_lock);
+ writing++;
+ pthread_mutex_unlock(&rimg_lock);
+}
+
+void finalize_recv_rimg(struct rimage *rimg)
+{
+
+ pthread_mutex_lock(&rimg_lock);
+
+ if (rimg)
+ list_add_tail(&(rimg->l), &rimg_head);
+ writing--;
+ pthread_mutex_unlock(&rimg_lock);
+ /* Wake thread waiting for this image. */
+ if (rimg) {
+ struct wthread *wt = get_wt_by_name(rimg->snapshot_id, rimg->path);
+ if (wt)
+ sem_post(&(wt->wakeup_sem));
+ }
+}
+
+bool is_receiving(void)
+{
+ int ret;
+
+ pthread_mutex_lock(&rimg_lock);
+ ret = writing;
+ pthread_mutex_unlock(&rimg_lock);
+ return ret > 0;
+}
+
+static void prepare_fwd_rimg(void)
+{
+ pthread_mutex_lock(&rimg_lock);
+ forwarding++;
+ pthread_mutex_unlock(&rimg_lock);
+}
+
+static void finalize_fwd_rimg(void)
+{
+ pthread_mutex_lock(&rimg_lock);
+ forwarding--;
+ pthread_mutex_unlock(&rimg_lock);
+}
+
+static bool is_forwarding(void)
+{
+ int ret;
+
+ pthread_mutex_lock(&rimg_lock);
+ ret = forwarding;
+ pthread_mutex_unlock(&rimg_lock);
+ return ret > 0;
+}
+
+/* This function is called when no more images are coming. Threads still
waiting
+ * for images will be awaken to send a ENOENT (no such file) to the
requester.
+ */
+void unlock_workers(void)
+{
+ struct wthread *wt = NULL;
+
+ pthread_mutex_lock(&workers_lock);
+ list_for_each_entry(wt, &workers_head, l)
+ sem_post(&(wt->wakeup_sem));
+ pthread_mutex_unlock(&workers_lock);
+}
+
+int init_daemon(bool background, struct rimage *(*wfi)(struct wthread*))
+{
+ if (background) {
+ if (daemon(1, 0) == -1) {
+ pr_perror("Can't run service server in the background");
+ return -1;
+ }
+ }
+ wait_for_image = wfi;
+ return init_sync_structures();
+}
+
+int setup_TCP_server_socket(int port)
+{
+ struct sockaddr_in serv_addr;
+ int sockopt = 1;
+ int sockfd = socket(AF_INET, SOCK_STREAM, 0);
+
+ if (sockfd < 0) {
+ pr_perror("Unable to open image socket");
+ return -1;
+ }
+
+ bzero((char *) &serv_addr, sizeof(serv_addr));
+ serv_addr.sin_family = AF_INET;
+ serv_addr.sin_addr.s_addr = INADDR_ANY;
+ serv_addr.sin_port = htons(port);
+
+ if (setsockopt(
+ sockfd, SOL_SOCKET, SO_REUSEADDR, &sockopt, sizeof(sockopt)) == -1) {
+ pr_perror("Unable to set SO_REUSEADDR");
+ return -1;
+ }
+
+ if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
+ pr_perror("Unable to bind image socket");
+ return -1;
+ }
+
+ if (listen(sockfd, DEFAULT_LISTEN)) {
+ pr_perror("Unable to listen image socket");
+ return -1;
+ }
+
+ return sockfd;
+}
+
+int setup_TCP_client_socket(char *hostname, int port)
+{
+ int sockfd;
+ struct sockaddr_in serv_addr;
+ struct hostent *server;
+
+ sockfd = socket(AF_INET, SOCK_STREAM, 0);
+ if (sockfd < 0) {
+ pr_perror("Unable to open remote image socket");
+ return -1;
+ }
+
+ server = gethostbyname(hostname);
+ if (server == NULL) {
+ pr_perror("Unable to get host by name (%s)", hostname);
+ return -1;
+ }
+
+ bzero((char *) &serv_addr, sizeof(serv_addr));
+ serv_addr.sin_family = AF_INET;
+ bcopy((char *) server->h_addr,
+ (char *) &serv_addr.sin_addr.s_addr,
+ server->h_length);
+ serv_addr.sin_port = htons(port);
+
+ if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) <
0) {
+ pr_perror("Unable to connect to remote %s", hostname);
+ return -1;
+ }
+
+ return sockfd;
+}
+
+int setup_UNIX_server_socket(char *path)
+{
+ struct sockaddr_un addr;
+ int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+
+ if (sockfd < 0) {
+ pr_perror("Unable to open image socket");
+ return -1;
+ }
+
+ memset(&addr, 0, sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ strncpy(addr.sun_path, path, sizeof(addr.sun_path)-1);
+
+ unlink(path);
+
+ if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+ pr_perror("Unable to bind image socket");
+ return -1;
+ }
+
+ if (listen(sockfd, 50) == -1) {
+ pr_perror("Unable to listen image socket");
+ return -1;
+ }
+
+ return sockfd;
+}
+
+int setup_UNIX_client_socket(char *path)
+{
+ struct sockaddr_un addr;
+ int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+
+ if (sockfd < 0) {
+ pr_perror("Unable to open local image socket");
+ return -1;
+ }
+
+ memset(&addr, 0, sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ strncpy(addr.sun_path, path, sizeof(addr.sun_path)-1);
+
+ if (connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+ pr_perror("Unable to connect to local socket: %s", path);
+ return -1;
+ }
+
+ return sockfd;
+}
+
+uint64_t pb_write_obj(int fd, void *obj, int type)
+{
+ struct cr_img img;
+
+ img._x.fd = fd;
+ bfd_setraw(&img._x);
+ return pb_write_one(&img, obj, type);
+}
+
+uint64_t pb_read_obj(int fd, void **pobj, int type)
+{
+ struct cr_img img;
+
+ img._x.fd = fd;
+ bfd_setraw(&img._x);
+ return do_pb_read_one(&img, pobj, type, true);
+}
+
+uint64_t write_header(int fd, char *snapshot_id, char *path, int flags)
+{
+ LocalImageEntry li = LOCAL_IMAGE_ENTRY__INIT;
+
+ li.name = path;
+ li.snapshot_id = snapshot_id;
+ li.open_mode = flags;
+ return pb_write_obj(fd, &li, PB_LOCAL_IMAGE);
+}
+
+uint64_t write_reply_header(int fd, int error)
+{
+ LocalImageReplyEntry lir = LOCAL_IMAGE_REPLY_ENTRY__INIT;
+
+ lir.error = error;
+ return pb_write_obj(fd, &lir, PB_LOCAL_IMAGE_REPLY);
+}
+
+uint64_t write_remote_header(int fd, char *snapshot_id, char *path, int
flags, uint64_t size)
+{
+ RemoteImageEntry ri = REMOTE_IMAGE_ENTRY__INIT;
+
+ ri.name = path;
+ ri.snapshot_id = snapshot_id;
+ ri.open_mode = flags;
+ ri.size = size;
+ return pb_write_obj(fd, &ri, PB_REMOTE_IMAGE);
+}
+
+uint64_t read_header(int fd, char *snapshot_id, char *path, int *flags)
+{
+ LocalImageEntry *li;
+ int ret = pb_read_obj(fd, (void **)&li, PB_LOCAL_IMAGE);
+
+ if (ret > 0) {
+ strncpy(snapshot_id, li->snapshot_id, PATHLEN);
+ strncpy(path, li->name, PATHLEN);
+ *flags = li->open_mode;
+ }
+ free(li);
+ return ret;
+}
+
+uint64_t read_reply_header(int fd, int *error)
+{
+ LocalImageReplyEntry *lir;
+ int ret = pb_read_obj(fd, (void **)&lir, PB_LOCAL_IMAGE_REPLY);
+
+ if (ret > 0)
+ *error = lir->error;
+ free(lir);
+ return ret;
+}
+
+uint64_t read_remote_header(int fd, char *snapshot_id, char *path, int
*flags, uint64_t *size)
+{
+ RemoteImageEntry *ri;
+ int ret = pb_read_obj(fd, (void **)&ri, PB_REMOTE_IMAGE);
+
+ if (ret > 0) {
+ strncpy(snapshot_id, ri->snapshot_id, PATHLEN);
+ strncpy(path, ri->name, PATHLEN);
+ *flags = ri->open_mode;
+ *size = ri->size;
+ }
+ free(ri);
+ return ret;
+}
+
+static struct wthread *new_worker(void)
+{
+ struct wthread *wt = malloc(sizeof(struct wthread));
+
+ if (!wt) {
+ pr_perror("Unable to allocate worker thread structure");
+ return NULL;
+ }
+ if (sem_init(&(wt->wakeup_sem), 0, 0) != 0) {
+ pr_perror("Workers semaphore init failed");
+ return NULL;
+ }
+ return wt;
+}
+
+static void add_worker(struct wthread *wt)
+{
+ pthread_mutex_lock(&workers_lock);
+ list_add_tail(&(wt->l), &workers_head);
+ pthread_mutex_unlock(&workers_lock);
+ sem_post(&workers_semph);
+}
+
+void join_workers(void)
+{
+ struct wthread *wthread = NULL;
+
+ while (! list_empty(&workers_head)) {
+ wthread = list_entry(workers_head.next, struct wthread, l);
+ pthread_join(wthread->tid, NULL);
+ list_del(&(wthread->l));
+ free(wthread);
+ }
+}
+
+static struct rimage *new_remote_image(char *path, char *snapshot_id)
+{
+ struct rimage *rimg = malloc(sizeof(struct rimage));
+ struct rbuf *buf = malloc(sizeof(struct rbuf));
+
+ if (rimg == NULL) {
+ pr_perror("Unable to allocate remote_image structures");
+ return NULL;
+ }
+
+ if (buf == NULL) {
+ pr_perror("Unable to allocate remote_buffer structures");
+ return NULL;
+ }
+
+ strncpy(rimg->path, path, PATHLEN);
+ strncpy(rimg->snapshot_id, snapshot_id, PATHLEN);
+ rimg->size = 0;
+ buf->nbytes = 0;
+ INIT_LIST_HEAD(&(rimg->buf_head));
+ list_add_tail(&(buf->l), &(rimg->buf_head));
+ rimg->curr_sent_buf = list_entry(rimg->buf_head.next, struct rbuf, l);
+ rimg->curr_sent_bytes = 0;
+
+ if (pthread_mutex_init(&(rimg->in_use), NULL) != 0) {
+ pr_perror("Remote image in_use mutex init failed");
+ return NULL;
+ }
+ return rimg;
+}
+
+/* Clears a remote image struct for reusing it. */
+static struct rimage *clear_remote_image(struct rimage *rimg)
+{
+ pthread_mutex_lock(&(rimg->in_use));
+
+ while (!list_is_singular(&(rimg->buf_head))) {
+ struct rbuf *buf = list_entry(rimg->buf_head.prev, struct rbuf, l);
+
+ list_del(rimg->buf_head.prev);
+ free(buf);
+ }
+
+ list_entry(rimg->buf_head.next, struct rbuf, l)->nbytes = 0;
+ rimg->size = 0;
+ rimg->curr_sent_buf = list_entry(rimg->buf_head.next, struct rbuf, l);
+ rimg->curr_sent_bytes = 0;
+
+ pthread_mutex_unlock(&(rimg->in_use));
+
+ return rimg;
+}
+
+struct rimage *prepare_remote_image(char *path, char *snapshot_id, int
open_mode)
+{
+ struct rimage *rimg = get_rimg_by_name(snapshot_id, path);
+ /* There is no record of such image, create a new one. */
+
+ if (rimg == NULL)
+ return new_remote_image(path, snapshot_id);
+
+ pthread_mutex_lock(&rimg_lock);
+ list_del(&(rimg->l));
+ pthread_mutex_unlock(&rimg_lock);
+
+ /* There is already an image record. Simply return it for appending. */
+ if (open_mode == O_APPEND)
+ return rimg;
+ /* There is already an image record. Clear it for writing. */
+ else
+ return clear_remote_image(rimg);
+}
+
+void *process_local_read(struct wthread *wt)
+{
+ struct rimage *rimg = NULL;
+ uint64_t ret;
+ /* TODO - split wait_for_image
+ * in cache - improve the parent stuf
+ * in proxy - do not wait for anything, return no file
+ */
+ rimg = wait_for_image(wt);
+ if (!rimg) {
+ pr_info("No image %s:%s.\n", wt->path, wt->snapshot_id);
+ if (write_reply_header(wt->fd, ENOENT) < 0)
+ pr_perror("Error writing reply header for
unexisting image");
+ close(wt->fd);
+ return NULL;
+ } else {
+ if (write_reply_header(wt->fd, 0) < 0) {
+ pr_perror("Error writing reply header for %s:%s",
+ wt->path, wt->snapshot_id);
+ close(wt->fd);
+ return NULL;
+ }
+ }
+
+ pthread_mutex_lock(&(rimg->in_use));
+ ret = send_image(wt->fd, rimg, wt->flags, true);
+ if (ret < 0)
+ pr_perror("Unable to send %s:%s to CRIU (sent %lu bytes)",
+ rimg->path, rimg->snapshot_id, ret);
+ else
+ pr_info("Finished sending %s:%s to CRIU (sent %lu
bytes)\n",
+ rimg->path, rimg->snapshot_id, ret);
+ pthread_mutex_unlock(&(rimg->in_use));
+ return NULL;
+}
+
+static void *process_local_image_connection(void *ptr)
+{
+ struct wthread *wt = (struct wthread *) ptr;
+ struct rimage *rimg = NULL;
+ uint64_t ret;
+
+ /* NOTE: the code inside this if is shared for both cache and proxy. */
+ if (wt->flags == O_RDONLY)
+ return process_local_read(wt);
+
+ /* NOTE: IMAGE PROXY ONLY. The image cache receives write connections
+ * through TCP (see accept_remote_image_connections).
+ */
+ rimg = prepare_remote_image(wt->path, wt->snapshot_id, wt->flags);
+ ret = recv_image(wt->fd, rimg, 0, wt->flags, true);
+ if (ret < 0) {
+ pr_perror("Unable to receive %s:%s to CRIU (received %lu
bytes)",
+ rimg->path, rimg->snapshot_id, ret);
+ finalize_recv_rimg(NULL);
+ return NULL;
+ }
+ finalize_recv_rimg(rimg);
+ pr_info("Finished receiving %s:%s (received %lu bytes)\n",
+ rimg->path, rimg->snapshot_id, ret);
+
+
+ if (!strncmp(rimg->path, DUMP_FINISH, sizeof(DUMP_FINISH))) {
+ finished = true;
+ shutdown(local_req_fd, SHUT_RD);
+ } else {
+ pthread_mutex_lock(&proxy_to_cache_lock);
+ ret = forward_image(rimg);
+ pthread_mutex_unlock(&proxy_to_cache_lock);
+ }
+
+ finalize_fwd_rimg();
+ if (ret < 0) {
+ pr_perror("Unable to forward %s:%s to Image Cache",
+ rimg->path, rimg->snapshot_id);
+
+ return NULL;
+ }
+
+ if (finished && !is_forwarding() && !is_receiving()) {
+ pr_info("Closing connection to Image Cache.\n");
+ close(proxy_to_cache_fd);
+ unlock_workers();
+ }
+ return NULL;
+}
+
+
+void *accept_local_image_connections(void *port)
+{
+ int fd = *((int *) port);
+ int cli_fd;
+ struct sockaddr_in cli_addr;
+
+ socklen_t clilen = sizeof(cli_addr);
+ pthread_t tid;
+ struct wthread *wt;
+
+ while (1) {
+ cli_fd = accept(fd, (struct sockaddr *) &cli_addr, &clilen);
+ if (cli_fd < 0) {
+ if (!finished)
+ pr_err("Unable to accept local image connection");
+ close(cli_fd);
+ return NULL;
+ }
+
+ wt = new_worker();
+ wt->fd = cli_fd;
+
+ if (read_header(wt->fd, wt->snapshot_id, wt->path, &(wt->flags)) < 0) {
+ pr_perror("Error reading local image header");
+ return NULL;
+ }
+
+ pr_info("Received %s request for %s:%s\n",
+ wt->flags == O_RDONLY ? "read" :
+ wt->flags == O_APPEND ? "append" : "write",
+ wt->path, wt->snapshot_id);
+
+ /* These function calls are used to avoid other threads from
+ * thinking that there are no more images are coming.
+ */
+ if (wt->flags != O_RDONLY) {
+ prepare_recv_rimg();
+ prepare_fwd_rimg();
+ }
+
+ /* We need to flock the last pid file to avoid stealing pids
+ * from restore.
+ */
+ int fd = open_proc_rw(PROC_GEN, LAST_PID_PATH);
+ if (fd < 0) {
+ pr_perror("Can't open %s", LAST_PID_PATH);
+ }
+
+ if (flock(fd, LOCK_EX)) {
+ close(fd);
+ pr_perror("Can't lock %s", LAST_PID_PATH);
+ return NULL;
+ }
+
+ if (pthread_create(
+ &tid, NULL, process_local_image_connection, (void *) wt)) {
+ pr_perror("Unable to create worker thread");
+ return NULL;
+ }
+
+ if (flock(fd, LOCK_UN))
+ pr_perror("Can't unlock %s", LAST_PID_PATH);
+ close(fd);
+
+ wt->tid = tid;
+ add_worker(wt);
+ }
+}
+
+/* Note: size is a limit on how much we want to read from the socket. Zero
means
+ * read until the socket is closed.
+ */
+uint64_t recv_image(int fd, struct rimage *rimg, uint64_t size, int flags,
bool close_fd)
+{
+ struct rbuf *curr_buf = NULL;
+ int n;
+
+ if (flags == O_APPEND)
+ curr_buf = list_entry(rimg->buf_head.prev, struct rbuf, l);
+ else
+ curr_buf = list_entry(rimg->buf_head.next, struct rbuf, l);
+
+ while (1) {
+ n = read(fd,
+ curr_buf->buffer + curr_buf->nbytes,
+ size ?
+ min((int) (size - rimg->size), BUF_SIZE - curr_buf->nbytes) :
+ BUF_SIZE - curr_buf->nbytes);
+ if (n == 0) {
+ if (close_fd)
+ close(fd);
+ return rimg->size;
+ } else if (n > 0) {
+ curr_buf->nbytes += n;
+ rimg->size += n;
+ if (curr_buf->nbytes == BUF_SIZE) {
+ struct rbuf *buf = malloc(sizeof(struct rbuf));
+ if (buf == NULL) {
+ pr_perror("Unable to allocate remote_buffer structures");
+ if (close_fd)
+ close(fd);
+ return -1;
+ }
+ buf->nbytes = 0;
+ list_add_tail(&(buf->l), &(rimg->buf_head));
+ curr_buf = buf;
+ }
+ if (size && rimg->size == size) {
+ if (close_fd)
+ close(fd);
+ return rimg->size;
+ }
+ } else {
+ pr_perror("Read on %s:%s socket failed",
+ rimg->path, rimg->snapshot_id);
+ if (close_fd)
+ close(fd);
+ return -1;
+ }
+ }
+}
+
+uint64_t send_image(int fd, struct rimage *rimg, int flags, bool close_fd)
+{
+
+ int n, nblocks = 0;
+
+ if (flags != O_APPEND) {
+ rimg->curr_sent_buf = list_entry(rimg->buf_head.next, struct rbuf, l);
+ rimg->curr_sent_bytes = 0;
+ }
+
+ while (1) {
+ n = send(
+ fd,
+ rimg->curr_sent_buf->buffer + rimg->curr_sent_bytes,
+ min(BUF_SIZE, rimg->curr_sent_buf->nbytes) - rimg->curr_sent_bytes,
+ MSG_NOSIGNAL);
+ if (n > -1) {
+ rimg->curr_sent_bytes += n;
+ if (rimg->curr_sent_bytes == BUF_SIZE) {
+ rimg->curr_sent_buf =
+ list_entry(rimg->curr_sent_buf->l.next, struct rbuf, l);
+ nblocks++;
+ rimg->curr_sent_bytes = 0;
+ } else if (rimg->curr_sent_bytes == rimg->curr_sent_buf->nbytes) {
+ if (close_fd)
+ close(fd);
+ return nblocks*BUF_SIZE + rimg->curr_sent_buf->nbytes;
+ }
+ } else if (errno == EPIPE || errno == ECONNRESET) {
+ pr_warn("Connection for %s:%s was closed early than expected\n",
+ rimg->path, rimg->snapshot_id);
+ return 0;
+ } else {
+ pr_perror("Write on %s:%s socket failed",
+ rimg->path, rimg->snapshot_id);
+ return -1;
+ }
+ }
+
+}
diff --git a/criu/include/img-remote-proto.h
b/criu/include/img-remote-proto.h
new file mode 100644
index 0000000..51ee2cd
--- /dev/null
+++ b/criu/include/img-remote-proto.h
@@ -0,0 +1,86 @@
+#ifndef IMAGE_REMOTE_PVT_H
+#define IMAGE_REMOTE_PVT_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include "common/list.h"
+#include "img-remote.h"
+#include <pthread.h>
+#include <semaphore.h>
+
+#define DEFAULT_LISTEN 50
+#define PAGESIZE 4096
+#define BUF_SIZE PAGESIZE
+
+struct rbuf {
+ char buffer[BUF_SIZE];
+ int nbytes; /* How many bytes are in the buffer. */
+ struct list_head l;
+};
+
+struct rimage {
+ char path[PATHLEN];
+ char snapshot_id[PATHLEN];
+ struct list_head l;
+ struct list_head buf_head;
+ /* Used to track already sent buffers when the image is appended. */
+ struct rbuf *curr_sent_buf;
+ /* Similar to the previous field. Number of bytes sent in
'curr_sent_buf'. */
+ int curr_sent_bytes;
+ uint64_t size; /* number of bytes */
+ pthread_mutex_t in_use; /* Only one operation at a time, per image. */
+};
+
+struct wthread {
+ pthread_t tid;
+ struct list_head l;
+ /* Client fd. */
+ int fd;
+ /* The path and snapshot_id identify the request handled by this thread.
*/
+ char path[PATHLEN];
+ char snapshot_id[PATHLEN];
+ int flags;
+ /* This semph is used to wake this thread if the image is in memory.*/
+ sem_t wakeup_sem;
+};
+
+/* This variable is used to indicate when the dump is finished. */
+extern bool finished;
+/* This is the proxy to cache TCP socket FD. */
+extern int proxy_to_cache_fd;
+/* This the unix socket used to fulfill local requests. */
+extern int local_req_fd;
+
+int init_daemon(bool background, struct rimage *(*wfi)(struct wthread*));
+
+void join_workers(void);
+void unlock_workers(void);
+
+void prepare_recv_rimg(void);
+void finalize_recv_rimg(struct rimage *rimg);
+struct rimage *prepare_remote_image(char *path, char *namesapce, int
flags);
+struct rimage *get_rimg_by_name(const char *snapshot_id, const char *path);
+bool is_receiving(void);
+
+void *accept_local_image_connections(void *ptr);
+void *accept_remote_image_connections(void *ptr);
+
+uint64_t forward_image(struct rimage *rimg);
+uint64_t send_image(int fd, struct rimage *rimg, int flags, bool
image_check);
+uint64_t recv_image(int fd, struct rimage *rimg, uint64_t size, int flags,
bool image_check);
+
+uint64_t pb_write_obj(int fd, void *obj, int type);
+uint64_t pb_read_obj(int fd, void **obj, int type);
+
+uint64_t write_header(int fd, char *snapshot_id, char *path, int
open_mode);
+uint64_t read_header(int fd, char *snapshot_id, char *path, int
*open_mode);
+uint64_t write_reply_header(int fd, int error);
+uint64_t read_reply_header(int fd, int *error);
+uint64_t read_remote_header(int fd, char *snapshot_id, char *path, int
*open_mode, uint64_t *size);
+uint64_t write_remote_header(int fd, char *snapshot_id, char *path, int
open_mode, uint64_t size);
+
+int setup_TCP_server_socket(int port);
+int setup_TCP_client_socket(char *hostname, int port);
+int setup_UNIX_client_socket(char *path);
+int setup_UNIX_server_socket(char *path);
+#endif
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