From: Andrew Cooper Date: Thu, 25 Jul 2024 14:22:46 +0000 (+0200) Subject: tools/libxs: Fix fcntl() invocation in set_cloexec() X-Git-Tag: RELEASE-4.17.5~12 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=3b7672193ae1199b02a6b73f8d6450d02a20c222;p=xen.git tools/libxs: Fix fcntl() invocation in set_cloexec() 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 Signed-off-by: Andrew Cooper Reviewed-by: Ross Lagerwall Reviewed-by: Juergen Gross master commit: 37810b52d003f8a04af41d7b1f85eff24af9f804 master date: 2024-07-09 15:32:18 +0100 --- diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c index 3f723bff5a..03f06e614e 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])