Date: Wed, 5 Jun 2013 21:30:01 GMT From: Guy Helmer <guy.helmer@gmail.com> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/113239: [patch] atrun(8) loses jobs due to race condition Message-ID: <201306052130.r55LU1L3050462@freefall.freebsd.org>
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The following reply was made to PR bin/113239; it has been noted by GNATS.
From: Guy Helmer <guy.helmer@gmail.com>
To: bug-followup@FreeBSD.org,
freebsd@sopwith.solgatos.com
Cc:
Subject: Re: bin/113239: [patch] atrun(8) loses jobs due to race condition
Date: Wed, 5 Jun 2013 16:13:09 -0500
I'm not comfortable with working around the race condition by =
determining whether a file seems "too old". Would serializing access to =
the queue work using the following patch:
Index: atrun.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- atrun.c (revision 251433)
+++ atrun.c (working copy)
@@ -31,6 +31,7 @@
/* System Headers */
=20
#include <sys/fcntl.h>
+#include <sys/file.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef __FreeBSD__
@@ -521,6 +522,9 @@
if ((spool =3D opendir(".")) =3D=3D NULL)
perr("cannot read %s", ATJOB_DIR);
=20
+ if (flock(dirfd(spool), LOCK_EX) =3D=3D -1)
+ perr("cannot lock %s", ATJOB_DIR);
+
now =3D time(NULL);
run_batch =3D 0;
batch_uid =3D (uid_t) -1;
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