This diff fixes the same problem ntpd(8) had with the dup2() when oldd == newd.
Quick background:
when you dup2(oldd, newd) and oldd == newd the CLOEXEC flag won't be removed
by the descriptor. We could use dup3() to detect this, but it is easier/faster
just to compare the fds and do the fcntl() ourselves.
ok?
Index: proc.c
===================================================================
RCS file: /home/obsdcvs/src/usr.sbin/httpd/proc.c,v
retrieving revision 1.27
diff -u -p -r1.27 proc.c
--- proc.c 28 Sep 2016 12:01:04 -0000 1.27
+++ proc.c 5 Oct 2016 16:50:40 -0000
@@ -22,6 +22,7 @@
#include <sys/socket.h>
#include <sys/wait.h>
+#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
@@ -131,7 +132,12 @@ proc_exec(struct privsep *ps, struct pri
break;
case 0:
/* Prepare parent socket. */
- dup2(fd, PROC_PARENT_SOCK_FILENO);
+ if (fd != PROC_PARENT_SOCK_FILENO) {
+ if (dup2(fd, PROC_PARENT_SOCK_FILENO)
+ == -1)
+ fatal("dup2");
+ } else if (fcntl(fd, F_SETFD, 0) == -1)
+ fatal("fcntl");
execvp(argv[0], nargv);
fatal("%s: execvp", __func__);
