This diff is an improvement and an attempt to fix the bug where the ntpd(8)
not always stays running.
During the review of syslogd fork+exec diff I noticed the use of dup3()
and went to read its man page: dup2() doesn't always remove the CLOEXEC
flag from the descriptor, so using dup3() is a better idea because it does
check the flag and if the oldd == newd then it retuns an useful error.
So if dup3() returns us an error it means oldd == newd and we should
remove the CLOEXEC flag ourself.
ok?
Index: util.c
===================================================================
RCS file: /home/obsdcvs/src/usr.sbin/ntpd/util.c,v
retrieving revision 1.22
diff -u -p -r1.22 util.c
--- util.c 14 Sep 2016 13:20:16 -0000 1.22
+++ util.c 2 Oct 2016 18:31:41 -0000
@@ -16,6 +16,8 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
+#include <errno.h>
+#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
@@ -184,7 +186,12 @@ start_child(char *pname, int cfd, int ar
break;
case 0:
/* Prepare the parent socket and execute. */
- dup2(cfd, PARENT_SOCK_FILENO);
+ if (dup3(cfd, PARENT_SOCK_FILENO, 0) == -1) {
+ if (errno != EINVAL)
+ fatal("%s: dup3", __func__);
+ if (fcntl(cfd, F_SETFD, 0) == -1)
+ fatal("%s: fcntl", __func__);
+ }
execvp(argv[0], nargv);
fatal("%s: execvp", __func__);
