libxl: introduce libxl_fd_set_nonblock, rationalise _cloexec

We want a function for setting fds to nonblocking, so introduce one.

This is a very similar requirement to that for libxl_fd_set_cloexec,
so make it common with that.

While we're at it, fix a few deficiences that make this latter
function less desirable than it could be:
 * Change the return from 0/-1 (like a syscall) to a libxl error code
 * Take a boolean parameter for turning the flag on and off
 * Log on error (and so, take a ctx for this purpose)

Change callers of libxl_fd_set_cloexec to notice errors.  (Although,
such errors are highly unlikely.)

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
index 6d401b7a42..f125b17fe3 100644
--- a/tools/libxl/libxl_qmp.c
+++ b/tools/libxl/libxl_qmp.c
@@ -325,7 +325,8 @@ static int qmp_open(libxl__qmp_handler *qmp, const char *qmp_socket_path,
     if (fcntl(qmp->qmp_fd, F_SETFL, flags | O_NONBLOCK) == -1) {
         return -1;
     }
-    libxl_fd_set_cloexec(qmp->qmp_fd);
+    ret = libxl_fd_set_cloexec(qmp->ctx, qmp->qmp_fd, 1);
+    if (ret) return -1;
 
     memset(&qmp->addr, 0, sizeof (&qmp->addr));
     qmp->addr.sun_family = AF_UNIX;