files: Generalize file open, get rid of explicit types switch

Introduce and use generic file_desc ops for this.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

files.c

@@ -45,10 +45,12 @@ int prepare_shared_fdinfo(void)
 	return 0;
 }
 
-void file_desc_add(struct file_desc *d, int type, u32 id)
+void file_desc_add(struct file_desc *d, int type, u32 id,
+		struct file_desc_ops *ops)
 {
 	d->type = type;
 	d->id = id;
+	d->ops = ops;
 	INIT_LIST_HEAD(&d->fd_info_head);
 
 	list_add_tail(&d->hash, &file_descs[id % FDESC_HASH_SIZE]);
@@ -109,6 +111,12 @@ static struct reg_file_info *find_reg_file(int id)
 	return container_of(fd, struct reg_file_info, d);
 }
 
+static int open_fe_fd(struct file_desc *d);
+
+static struct file_desc_ops reg_desc_ops = {
+	.open = open_fe_fd,
+};
+
 int collect_reg_files(void)
 {
 	struct reg_file_info *rfi = NULL;
@@ -144,7 +152,8 @@ int collect_reg_files(void)
 		rfi->path[len] = '\0';
 
 		pr_info("Collected [%s] ID %x\n", rfi->path, rfi->rfe.id);
-		file_desc_add(&rfi->d, FDINFO_REG, rfi->rfe.id);
+		file_desc_add(&rfi->d, FDINFO_REG, rfi->rfe.id,
+				&reg_desc_ops);
 	}
 
 	if (rfi) {
@@ -303,12 +312,10 @@ void transport_name_gen(struct sockaddr_un *addr, int *len,
 
 static int should_open_transport(struct fdinfo_entry *fe, struct file_desc *fd)
 {
-	if (fe->type == FDINFO_PIPE)
-		return pipe_should_open_transport(fe, fd);
-	if (fe->type == FDINFO_UNIXSK)
-		return unixsk_should_open_transport(fe, fd);
-
-	return 0;
+	if (fd->ops->want_transport)
+		return fd->ops->want_transport(fe, fd);
+	else
+		return 0;
 }
 
 static int open_transport_fd(int pid, struct fdinfo_entry *fe, struct file_desc *d)
@@ -372,24 +379,7 @@ static int open_fd(int pid, struct fdinfo_entry *fe,
 	if ((fle->pid != pid) || (fe->addr != fle->fd))
 		return 0;
 
-	switch (fe->type) {
-	case FDINFO_REG:
-		tmp = open_fe_fd(d);
-		break;
-	case FDINFO_INETSK:
-		tmp = open_inet_sk(d);
-		break;
-	case FDINFO_PIPE:
-		tmp = open_pipe(d);
-		break;
-	case FDINFO_UNIXSK:
-		tmp = open_unix_sk(d);
-		break;
-	default:
-		tmp = -1;
-		break;
-	}
-
+	tmp = d->ops->open(d);
 	if (tmp < 0)
 		return -1;
 

include/files.h

@@ -39,14 +39,23 @@ struct fdinfo_list_entry {
 	futex_t			real_pid;
 };
 
+struct file_desc;
+
+struct file_desc_ops {
+	int (*open)(struct file_desc *);
+	int (*want_transport)(struct fdinfo_entry *, struct file_desc *);
+};
+
 struct file_desc {
 	int type;
 	u32 id;
 	struct list_head hash;
 	struct list_head fd_info_head;
+	struct file_desc_ops *ops;
 };
 
-extern void file_desc_add(struct file_desc *d, int type, u32 id);
+extern void file_desc_add(struct file_desc *d, int type, u32 id,
+		struct file_desc_ops *ops);
 extern struct fdinfo_list_entry *file_master(struct file_desc *d);
 extern struct file_desc *find_file_desc_raw(int type, u32 id);
 
@@ -65,8 +74,5 @@ extern int self_exe_fd;
 struct file_desc;
 extern int collect_pipes(void);
 extern void mark_pipe_master(void);
-extern int open_pipe(struct file_desc *);
-extern int pipe_should_open_transport(struct fdinfo_entry *fe,
-		struct file_desc *d);
 
 #endif /* FILES_H_ */

include/sockets.h

@@ -13,15 +13,11 @@ extern int dump_socket(struct fd_parms *p, int lfd,
 struct fdinfo_list_entry;
 struct file_desc;
 struct fdinfo_entry;
-extern int unixsk_should_open_transport(struct fdinfo_entry *,
-		struct file_desc *);
 extern int collect_sockets(void);
 extern int collect_inet_sockets(void);
 extern int collect_unix_sockets(void);
 extern int resolve_unix_peers(void);
 extern int run_unix_connections(void);
-extern int open_inet_sk(struct file_desc *);
-extern int open_unix_sk(struct file_desc *);
 struct cr_options;
 extern void show_unixsk(int fd, struct cr_options *);
 extern void show_inetsk(int fd, struct cr_options *);

pipes.c

@@ -35,6 +35,15 @@ static struct pipe_info *find_pipe(int id)
 	return container_of(fd, struct pipe_info, d);
 }
 
+static int open_pipe(struct file_desc *d);
+static int pipe_should_open_transport(struct fdinfo_entry *fe,
+		struct file_desc *d);
+
+static struct file_desc_ops pipe_desc_ops = {
+	.open = open_pipe,
+	.want_transport = pipe_should_open_transport,
+};
+
 int collect_pipes(void)
 {
 	struct pipe_info *pi = NULL, *tmp;
@@ -59,7 +68,8 @@ int collect_pipes(void)
 		pr_info("Collected pipe entry ID %x PIPE ID %x\n",
 					pi->pe.id, pi->pe.pipe_id);
 
-		file_desc_add(&pi->d, FDINFO_PIPE, pi->pe.id);
+		file_desc_add(&pi->d, FDINFO_PIPE, pi->pe.id,
+				&pipe_desc_ops);
 
 		list_for_each_entry(tmp, &pipes, list)
 			if (pi->pe.pipe_id == tmp->pe.pipe_id)
@@ -173,7 +183,7 @@ void mark_pipe_master()
 	handle_pipes_data();
 }
 
-int pipe_should_open_transport(struct fdinfo_entry *fe,
+static int pipe_should_open_transport(struct fdinfo_entry *fe,
 		struct file_desc *d)
 {
 	struct pipe_info *pi;
@@ -256,7 +266,7 @@ err:
 	return ret;
 }
 
-int open_pipe(struct file_desc *d)
+static int open_pipe(struct file_desc *d)
 {
 	unsigned long time = 1000;
 	struct pipe_info *pi, *pc, *p;

sockets.c

@@ -894,6 +894,12 @@ struct inet_sk_info {
 	struct file_desc d;
 };
 
+static int open_inet_sk(struct file_desc *d);
+
+static struct file_desc_ops inet_desc_ops = {
+	.open = open_inet_sk,
+};
+
 int collect_inet_sockets(void)
 {
 	struct inet_sk_info *ii = NULL;
@@ -913,7 +919,8 @@ int collect_inet_sockets(void)
 		if (ret <= 0)
 			break;
 
-		file_desc_add(&ii->d, FDINFO_INETSK, ii->ie.id);
+		file_desc_add(&ii->d, FDINFO_INETSK, ii->ie.id,
+				&inet_desc_ops);
 	}
 
 	if (ii)
@@ -923,7 +930,7 @@ int collect_inet_sockets(void)
 	return 0;
 }
 
-int open_inet_sk(struct file_desc *d)
+static int open_inet_sk(struct file_desc *d)
 {
 	int sk;
 	struct sockaddr_in addr;
@@ -1235,7 +1242,7 @@ done:
 	return 0;
 }
 
-int unixsk_should_open_transport(struct fdinfo_entry *fe,
+static int unixsk_should_open_transport(struct fdinfo_entry *fe,
 				struct file_desc *d)
 {
 	struct unix_sk_info *ui;
@@ -1360,6 +1367,11 @@ int open_unix_sk(struct file_desc *d)
 		return open_unixsk_standalone(ui);
 }
 
+static struct file_desc_ops unix_desc_ops = {
+	.open = open_unix_sk,
+	.want_transport = unixsk_should_open_transport,
+};
+
 int collect_unix_sockets(void)
 {
 	int fd, ret;
@@ -1416,7 +1428,8 @@ int collect_unix_sockets(void)
 		ui->peer = NULL;
 		ui->flags = 0;
 		pr_info(" `- Got %u peer %u\n", ui->ue.id, ui->ue.peer);
-		file_desc_add(&ui->d, FDINFO_UNIXSK, ui->ue.id);
+		file_desc_add(&ui->d, FDINFO_UNIXSK, ui->ue.id,
+				&unix_desc_ops);
 		list_add_tail(&ui->list, &unix_sockets);
 	}