From 6b3f6f4466e5584f2bdefc55b3ca34186b65acb9 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sat, 15 Oct 2011 19:06:28 +0200
Subject: [PATCH] add support for tracking open file descriptors of modules and
 closing them for created child processes

---
 main.c        | 23 +++++++++++++++++++++++
 netifd.h      |  9 +++++++++
 proto-shell.c | 13 +++++++------
 ubus.c        |  3 +++
 4 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/main.c b/main.c
index 04d5648..6419fe9 100644
--- a/main.c
+++ b/main.c
@@ -14,7 +14,9 @@ unsigned int debug_mask = 0;
 const char *main_path = DEFAULT_MAIN_PATH;
 const char *resolv_conf = DEFAULT_RESOLV_CONF;
 static char **global_argv;
+
 static struct list_head process_list = LIST_HEAD_INIT(process_list);
+static struct list_head fds = LIST_HEAD_INIT(fds);
 
 static void
 netifd_process_cb(struct uloop_process *proc, int ret)
@@ -28,6 +30,7 @@ netifd_process_cb(struct uloop_process *proc, int ret)
 int
 netifd_start_process(const char **argv, char **env, struct netifd_process *proc)
 {
+	struct netifd_fd *fd;
 	int pid;
 
 	netifd_kill_process(proc);
@@ -44,6 +47,14 @@ netifd_start_process(const char **argv, char **env, struct netifd_process *proc)
 		}
 		if (proc->dir_fd >= 0)
 			fchdir(proc->dir_fd);
+
+		/* close all non-essential fds */
+		list_for_each_entry(fd, &fds, list) {
+			if (fd->proc == proc)
+				continue;
+			close(fd->fd);
+		}
+
 		execvp(argv[0], (char **) argv);
 		exit(127);
 	}
@@ -70,6 +81,18 @@ netifd_kill_process(struct netifd_process *proc)
 	list_del(&proc->list);
 }
 
+void
+netifd_fd_add(struct netifd_fd *fd)
+{
+	list_add_tail(&fd->list, &fds);
+}
+
+void
+netifd_fd_delete(struct netifd_fd *fd)
+{
+	list_del(&fd->list);
+}
+
 static void netifd_do_restart(struct uloop_timeout *timeout)
 {
 	execvp(global_argv[0], global_argv);
diff --git a/netifd.h b/netifd.h
index f86fb15..4129af7 100644
--- a/netifd.h
+++ b/netifd.h
@@ -48,6 +48,12 @@ static inline void no_debug(int level, const char *fmt, ...)
 {
 }
 
+struct netifd_fd {
+	struct list_head list;
+	struct netifd_process *proc;
+	int fd;
+};
+
 struct netifd_process {
 	struct list_head list;
 	struct uloop_process uloop;
@@ -58,6 +64,9 @@ struct netifd_process {
 int netifd_start_process(const char **argv, char **env, struct netifd_process *proc);
 void netifd_kill_process(struct netifd_process *proc);
 
+void netifd_fd_add(struct netifd_fd *fd);
+void netifd_fd_delete(struct netifd_fd *fd);
+
 struct device;
 struct interface;
 
diff --git a/proto-shell.c b/proto-shell.c
index d0028c4..c0af99f 100644
--- a/proto-shell.c
+++ b/proto-shell.c
@@ -18,7 +18,7 @@
 #include "interface-ip.h"
 #include "proto.h"
 
-static int proto_fd;
+static struct netifd_fd proto_fd;
 
 struct proto_shell_handler {
 	struct list_head list;
@@ -469,11 +469,11 @@ proto_shell_attach(const struct proto_handler *h, struct interface *iface,
 	state->proto.cb = proto_shell_handler;
 	state->setup_timeout.cb = proto_shell_setup_timeout_cb;
 	state->setup_task.cb = proto_shell_setup_cb;
-	state->setup_task.dir_fd = proto_fd;
+	state->setup_task.dir_fd = proto_fd.fd;
 	state->teardown_task.cb = proto_shell_teardown_cb;
-	state->teardown_task.dir_fd = proto_fd;
+	state->teardown_task.dir_fd = proto_fd.fd;
 	state->proto_task.cb = proto_shell_task_cb;
-	state->proto_task.dir_fd = proto_fd;
+	state->proto_task.dir_fd = proto_fd.fd;
 	state->handler = container_of(h, struct proto_shell_handler, proto);
 
 	return &state->proto;
@@ -676,10 +676,11 @@ void __init proto_shell_init(void)
 	if (chdir("./proto"))
 		goto close_cur;
 
-	proto_fd = open(".", O_RDONLY | O_DIRECTORY);
-	if (proto_fd < 0)
+	proto_fd.fd = open(".", O_RDONLY | O_DIRECTORY);
+	if (proto_fd.fd < 0)
 		goto close_cur;
 
+	netifd_fd_add(&proto_fd);
 	glob("./*.sh", 0, NULL, &g);
 	for (i = 0; i < g.gl_pathc; i++)
 		proto_shell_add_script(g.gl_pathv[i]);
diff --git a/ubus.c b/ubus.c
index ba9fb9e..c47f459 100644
--- a/ubus.c
+++ b/ubus.c
@@ -11,6 +11,7 @@
 
 static struct ubus_context *ctx = NULL;
 static struct blob_buf b;
+static struct netifd_fd ubus_fd;
 
 /* global object */
 
@@ -105,6 +106,8 @@ netifd_ubus_init(const char *path)
 	DPRINTF("connected as %08x\n", ctx->local_id);
 	uloop_init();
 	ubus_add_uloop(ctx);
+	ubus_fd.fd = ctx->sock.fd;
+	netifd_fd_add(&ubus_fd);
 
 	ret = ubus_add_object(ctx, &main_object);
 	if (ret)
-- 
2.25.1