pipes: add functions for collecting pipes

pipe_entry is encapsulated in pipe_info.
All pipe_info-s connects in the list pipes.
All pipe_info-s with the same piep_id connects to pipe_list,
it a circular list without a defined head.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-restore.c

@@ -284,6 +284,9 @@ static int prepare_shared(void)
 	if (collect_reg_files())
 		return -1;
 
+	if (collect_pipes())
+		return -1;
+
 	if (collect_inet_sockets())
 		return -1;
 
@@ -301,6 +304,8 @@ static int prepare_shared(void)
 			break;
 	}
 
+	mark_pipe_master();
+
 	if (!ret) {
 		show_saved_shmems();
 		show_saved_files();

files.c

@@ -88,6 +88,8 @@ static struct list_head *find_fi_list(struct fdinfo_entry *fe)
 		return find_reg_fd(fe->id);
 	if (fe->type == FDINFO_INETSK)
 		return find_inetsk_fd(fe->id);
+	if (fe->type == FDINFO_PIPE)
+		return find_pipe_fd(fe->id);
 
 	BUG_ON(1);
 	return NULL;

include/files.h

@@ -55,4 +55,8 @@ extern int get_filemap_fd(int pid, struct vma_entry *vma_entry);
 
 extern int self_exe_fd;
 
+extern int collect_pipes(void);
+extern void mark_pipe_master(void);
+struct list_head *find_pipe_fd(int id);
+
 #endif /* FILES_H_ */

pipes.c

@@ -1,4 +1,146 @@
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
 #include "crtools.h"
 #include "image.h"
 #include "files.h"
+#include "util-net.h"
 
+/* The sequence of objects which should be restored:
+ * pipe -> files struct-s -> fd-s.
+ * pipe_entry describes  pipe's file structs-s.
+ * A pipe has not own properties, so it has not own object.
+ */
+
+struct pipe_info {
+	struct pipe_entry pe;
+	struct list_head pipe_list;	/* all pipe_info with the same pipe_id
+					 * This is pure circular list whiout head */
+	struct list_head list;		/* list head for fdinfo_list_entry-s */
+	struct list_head fd_head;
+	int create;
+};
+
+static LIST_HEAD(pipes);
+
+static struct pipe_info *find_pipe(int id)
+{
+	struct pipe_info *pi;
+
+	list_for_each_entry(pi, &pipes, list)
+		if (pi->pe.id == id)
+			return pi;
+	return NULL;
+}
+
+struct list_head *find_pipe_fd(int id)
+{
+	struct pipe_info *pi;
+
+	pi = find_pipe(id);
+	return &pi->fd_head;
+}
+
+int collect_pipes(void)
+{
+	struct pipe_info *pi = NULL, *tmp;
+	int fd, ret = -1;
+
+	fd = open_image_ro(CR_FD_PIPES);
+	if (fd < 0)
+		return -1;
+
+	while (1) {
+		int len;
+
+		pi = xmalloc(sizeof(*pi));
+		ret = -1;
+		if (pi == NULL)
+			break;
+
+		ret = read_img_eof(fd, &pi->pe);
+		if (ret <= 0)
+			break;
+
+		lseek(fd, pi->pe.bytes, SEEK_CUR);
+
+		pr_info("Collected pipe entry ID %x PIPE ID %x\n",
+					pi->pe.id, pi->pe.pipe_id);
+		INIT_LIST_HEAD(&pi->fd_head);
+
+		list_for_each_entry(tmp, &pipes, list)
+			if (pi->pe.pipe_id == tmp->pe.pipe_id)
+				break;
+
+		if (&tmp->list == &pipes)
+			INIT_LIST_HEAD(&pi->pipe_list);
+		else
+			list_add(&pi->pipe_list, &tmp->pipe_list);
+
+		list_add_tail(&pi->list, &pipes);
+	}
+
+	xfree(pi);
+
+	close(fd);
+	return ret;
+}
+
+static void show_saved_pipe_fds(struct pipe_info *pi)
+{
+	struct fdinfo_list_entry *fle;
+
+	pr_info("  `- ID %p %xpn", pi, pi->pe.id);
+	list_for_each_entry(fle, &pi->fd_head, list)
+		pr_info("   `- FD %d pid %d\n", fle->fd, fle->pid);
+}
+
+/* Choose who will restore a pipe. */
+void mark_pipe_master()
+{
+	LIST_HEAD(head);
+
+	pr_info("Pipes:\n");
+
+	while (1) {
+		struct fdinfo_list_entry *fle;
+		struct pipe_info *pi, *pic, *p;
+		int fd, pid;
+
+		if (list_empty(&pipes))
+			break;
+
+		pi = list_first_entry(&pipes, struct pipe_info, list);
+		list_move(&pi->list, &head);
+
+		pr_info(" `- PIPE ID %x\n", pi->pe.pipe_id);
+		show_saved_pipe_fds(pi);
+
+		fle = list_first_entry(&pi->fd_head,
+				struct fdinfo_list_entry, list);
+		p = pi;
+		fd = fle->fd;
+		pid = fle->pid;
+
+		list_for_each_entry(pic, &pi->pipe_list, pipe_list) {
+			list_move(&pic->list, &head);
+
+			fle = list_first_entry(&p->fd_head,
+					struct fdinfo_list_entry, list);
+			if (fle->pid < pid ||
+			    (pid == fle->pid && fle->fd < fd)) {
+				p = pic;
+				fd = fle->fd;
+				pid = fle->pid;
+			}
+
+			show_saved_pipe_fds(pic);
+		}
+		p->create = 1;
+		pr_info("    by %x\n", p->pe.id);
+	}
+
+	list_splice(&head, &pipes);
+}