dump: Introduce file dumping operations

Now all the fds dump look very similar and we can reimplement
it via indirect calls.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -287,8 +287,7 @@ static int dump_one_reg_file(int lfd, u32 id, const struct fd_parms *p)
 	pr_info("Dumping path for %d fd via self %d [%s]\n",
 			p->fd, lfd, big_buffer);
 
-	if (p->type == FDINFO_REG &&
-			check_path_remap(big_buffer, &p->stat, lfd, id))
+	if (check_path_remap(big_buffer, &p->stat, lfd, id))
 		return -1;
 
 	rfe.len = len;
@@ -307,36 +306,61 @@ static int dump_one_reg_file(int lfd, u32 id, const struct fd_parms *p)
 	return 0;
 }
 
-static int do_dump_gen_file(const struct fd_parms *p, int lfd,
-			     const struct cr_fdset *cr_fdset)
+struct fdtype_ops {
+	unsigned int	type;
+	u32		(*make_gen_id)(const struct fd_parms *p);
+	int		(*dump)(int lfd, u32 id, const struct fd_parms *p);
+};
+
+static u32 make_gen_id(const struct fd_parms *p)
+{
+	return MAKE_FD_GENID(p->stat.st_dev, p->stat.st_ino, p->pos);
+}
+
+static const struct fdtype_ops pipe_ops = {
+	.type		= FDINFO_PIPE,
+	.make_gen_id	= make_gen_id,
+	.dump		= dump_one_pipe,
+};
+
+static const struct fdtype_ops eventfd_ops = {
+	.type		= FDINFO_EVENTFD,
+	.make_gen_id	= make_gen_id,
+	.dump		= dump_one_eventfd,
+};
+
+static const struct fdtype_ops eventpoll_ops = {
+	.type		= FDINFO_EVENTPOLL,
+	.make_gen_id	= make_gen_id,
+	.dump		= dump_one_eventpoll,
+};
+
+static const struct fdtype_ops inotify_ops = {
+	.type		= FDINFO_INOTIFY,
+	.make_gen_id	= make_gen_id,
+	.dump		= dump_one_inotify,
+};
+
+static const struct fdtype_ops regfile_ops = {
+	.type		= FDINFO_REG,
+	.make_gen_id	= make_gen_id,
+	.dump		= dump_one_reg_file,
+};
+
+static int do_dump_gen_file(struct fd_parms *p, int lfd,
+		const struct fdtype_ops *ops, const struct cr_fdset *cr_fdset)
 {
 	struct fdinfo_entry e;
 	int ret = -1;
 
-	e.type	= p->type;
+	e.type	= ops->type;
+	e.id	= p->id = ops->make_gen_id(p);
 	e.fd	= p->fd;
-	e.id	= p->id;
 	e.flags = p->fd_flags;
 
 	ret = fd_id_generate(p->pid, &e);
 	if (ret == 1) /* new ID generated */
-		switch (p->type) {
-		case FDINFO_PIPE:
-			ret = dump_one_pipe(lfd, e.id, p);
-			break;
-		case FDINFO_EVENTFD:
-			ret = dump_one_eventfd(lfd, e.id, p);
-			break;
-		case FDINFO_EVENTPOLL:
-			ret = dump_one_eventpoll(lfd, e.id, p);
-			break;
-		case FDINFO_INOTIFY:
-			ret = dump_one_inotify(lfd, e.id, p);
-			break;
-		default:
-			ret = dump_one_reg_file(lfd, e.id, p);
-			break;
-		}
+		ret = ops->dump(lfd, e.id, p);
 
 	if (ret < 0)
 		goto err;
@@ -355,17 +379,13 @@ err:
 static int dump_reg_file(struct fd_parms *p, int lfd,
 			     const struct cr_fdset *cr_fdset)
 {
-	p->id = MAKE_FD_GENID(p->stat.st_dev, p->stat.st_ino, p->pos);
-	p->type = FDINFO_REG;
-	return do_dump_gen_file(p, lfd, cr_fdset);
+	return do_dump_gen_file(p, lfd, &regfile_ops, cr_fdset);
 }
 
 static int dump_pipe(struct fd_parms *p, int lfd,
 			     const struct cr_fdset *cr_fdset)
 {
-	p->id = MAKE_FD_GENID(p->stat.st_dev, p->stat.st_ino, p->pos);
-	p->type = FDINFO_PIPE;
-	return do_dump_gen_file(p, lfd, cr_fdset);
+	return do_dump_gen_file(p, lfd, &pipe_ops, cr_fdset);
 }
 
 static int dump_task_exe_link(pid_t pid, struct mm_entry *mm)
@@ -471,23 +491,17 @@ static int dump_chrdev(struct fd_parms *p, int lfd, const struct cr_fdset *set)
 
 static int dump_eventfd(struct fd_parms *p, int lfd, const struct cr_fdset *set)
 {
-	p->id = MAKE_FD_GENID(p->stat.st_dev, p->stat.st_ino, p->pos);
-	p->type	= FDINFO_EVENTFD;
-	return do_dump_gen_file(p, lfd, set);
+	return do_dump_gen_file(p, lfd, &eventfd_ops, set);
 }
 
 static int dump_eventpoll(struct fd_parms *p, int lfd, const struct cr_fdset *set)
 {
-	p->id = MAKE_FD_GENID(p->stat.st_dev, p->stat.st_ino, p->pos);
-	p->type	= FDINFO_EVENTPOLL;
-	return do_dump_gen_file(p, lfd, set);
+	return do_dump_gen_file(p, lfd, &eventpoll_ops, set);
 }
 
 static int dump_inotify(struct fd_parms *p, int lfd, const struct cr_fdset *set)
 {
-	p->id = MAKE_FD_GENID(p->stat.st_dev, p->stat.st_ino, p->pos);
-	p->type	= FDINFO_INOTIFY;
-	return do_dump_gen_file(p, lfd, set);
+	return do_dump_gen_file(p, lfd, &inotify_ops, set);
 }
 
 #ifndef PIPEFS_MAGIC