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authorJeff Dike <jdike@addtoit.com>2006-02-07 21:58:41 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-08 01:12:32 +0100
commit1d2ddcfb1935c9c0e98c4295458b01f24e3274f9 (patch)
tree94bc4ad32840430b22e22057dbf8deb70e72492a /arch/um/drivers
parent[PATCH] uml: add debug switch for skas mode (diff)
downloadlinux-1d2ddcfb1935c9c0e98c4295458b01f24e3274f9.tar.xz
linux-1d2ddcfb1935c9c0e98c4295458b01f24e3274f9.zip
[PATCH] uml: close TUN/TAP file descriptors
When UML opens a TUN/TAP device, the file descriptor could be copied into later, long-lived threads, holding the device open even after the interface is taken down, preventing it from being brought up again. This patch makes these descriptors close-on-exec so that they disappear from helper processes, and adds CLONE_FILES to a UML helper thread so that the descriptors are closed in the thread when they are closed elsewhere in UML. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um/drivers')
-rw-r--r--arch/um/drivers/chan_user.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index 5d50d4a44abf..2f880cb167a5 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -9,6 +9,7 @@
#include <termios.h>
#include <string.h>
#include <signal.h>
+#include <sched.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
@@ -73,7 +74,6 @@ static void winch_handler(int sig)
struct winch_data {
int pty_fd;
int pipe_fd;
- int close_me;
};
static int winch_thread(void *arg)
@@ -84,7 +84,6 @@ static int winch_thread(void *arg)
int count, err;
char c = 1;
- os_close_file(data->close_me);
pty_fd = data->pty_fd;
pipe_fd = data->pipe_fd;
count = os_write_file(pipe_fd, &c, sizeof(c));
@@ -153,15 +152,16 @@ static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out)
}
data = ((struct winch_data) { .pty_fd = fd,
- .pipe_fd = fds[1],
- .close_me = fds[0] } );
- err = run_helper_thread(winch_thread, &data, 0, &stack, 0);
+ .pipe_fd = fds[1] } );
+ /* CLONE_FILES so this thread doesn't hold open files which are open
+ * now, but later closed. This is a problem with /dev/net/tun.
+ */
+ err = run_helper_thread(winch_thread, &data, CLONE_FILES, &stack, 0);
if(err < 0){
printk("fork of winch_thread failed - errno = %d\n", errno);
goto out_close;
}
- os_close_file(fds[1]);
*fd_out = fds[0];
n = os_read_file(fds[0], &c, sizeof(c));
if(n != sizeof(c)){
@@ -169,13 +169,12 @@ static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out)
printk("read failed, err = %d\n", -n);
printk("fd %d will not support SIGWINCH\n", fd);
err = -EINVAL;
- goto out_close1;
+ goto out_close;
}
return err ;
out_close:
os_close_file(fds[1]);
- out_close1:
os_close_file(fds[0]);
out:
return err;