set_cloexec() had a bit too much copy&pate from setnonblock(), and
insufficient testing on ancient versions of Linux...
As written (emulating ancient linux by undef'ing O_CLOEXEC), strace shows:
open("/dev/xen/xenbus", O_RDWR) = 3
fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE)
fcntl(3, 0x8003 /* F_??? */, 0x7ffe4a771d90) = -1 EINVAL (Invalid argument)
close(3) = 0
which is obviously nonsense.
Switch F_GETFL -> F_GETFD, and fix the second invocation to use F_SETFD. With
this, strace is rather happer:
open("/dev/xen/xenbus", O_RDWR) = 3
fcntl(3, F_GETFD) = 0
fcntl(3, F_SETFD, FD_CLOEXEC) = 0
Fixes: bf7c1464706a ("tools/libxs: Fix CLOEXEC handling in get_dev()")
Reported-by: Ross Lagerwall <[email protected]>
Signed-off-by: Andrew Cooper <[email protected]>
---
CC: Anthony PERARD <[email protected]>
CC: Juergen Gross <[email protected]>
CC: Ross Lagerwall <[email protected]>
CC: Oleksii Kurochko <[email protected]>
CC: Jan Beulich <[email protected]>
I'm embarassed to say that this was only spotted by Ross when I was
cherrypicking fixes from staging-4.17 into the XenServer patchqueue.
This is urgent to take for 4.19, and to backport into 4.17/18 seeing as the
breakage has been backported already.
---
tools/libs/store/xs.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c
index c8845b69e284..38a6ce3cf2ea 100644
--- a/tools/libs/store/xs.c
+++ b/tools/libs/store/xs.c
@@ -182,12 +182,12 @@ static bool setnonblock(int fd, int nonblock) {
static bool set_cloexec(int fd)
{
- int flags = fcntl(fd, F_GETFL);
+ int flags = fcntl(fd, F_GETFD);
if (flags < 0)
return false;
- return fcntl(fd, flags | FD_CLOEXEC) >= 0;
+ return fcntl(fd, F_SETFD, flags | FD_CLOEXEC) >= 0;
}
static int pipe_cloexec(int fds[2])
--
2.39.2
