Previous commit was too restrictive: just ignore the CLONE_FS flag

when not doing CLONE_THREAD, like we did before, instead of treating
it as an error.  This unbreaks Opera running in linux compat.

Also, Linux completely ignores CLONE_DETACHED, so do that too, and
consistently refer to the flags in comment via their Linux names
without trying to abbreviate them further.

Problem found and fix confirmed by sturm@

1 files changed, 30 insertions, 14 deletions

diff --git a/sys/compat/linux/linux_sched.c b/sys/compat/linux/linux_sched.c
index f2011ea95b2..7500d978231 100644
--- a/sys/compat/linux/linux_sched.c
+++ b/sys/compat/linux/linux_sched.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: linux_sched.c,v 1.7 2009/12/28 02:54:24 guenther Exp $	*/
+/*	$OpenBSD: linux_sched.c,v 1.8 2010/01/04 19:27:21 guenther Exp $	*/
 /*	$NetBSD: linux_sched.c,v 1.6 2000/05/28 05:49:05 thorpej Exp $	*/
 
 /*-
@@ -73,7 +73,7 @@ linux_sys_clone(p, v, retval)
 	if (cflags & ~(LINUX_CLONE_CSIGNAL | LINUX_CLONE_VM | LINUX_CLONE_FS |
 	    LINUX_CLONE_FILES | LINUX_CLONE_SIGHAND | LINUX_CLONE_VFORK |
 	    LINUX_CLONE_PARENT | LINUX_CLONE_THREAD | LINUX_CLONE_SYSVSEM |
-	    LINUX_CLONE_UNTRACED))
+	    LINUX_CLONE_DETACHED | LINUX_CLONE_UNTRACED))
 		return (EINVAL);
 
 	if (cflags & LINUX_CLONE_VM)
@@ -81,7 +81,7 @@ linux_sys_clone(p, v, retval)
 	if (cflags & LINUX_CLONE_FILES)
 		flags |= FORK_SHAREFILES;
 	if (cflags & LINUX_CLONE_SIGHAND) {
-		/* According to Linux, SIGHAND requires VM */
+		/* According to Linux, CLONE_SIGHAND requires CLONE_VM */
 		if ((cflags & LINUX_CLONE_VM) == 0)
 			return (EINVAL);
 		flags |= FORK_SIGHAND;
@@ -90,10 +90,11 @@ linux_sys_clone(p, v, retval)
 		flags |= FORK_PPWAIT;
 	if (cflags & LINUX_CLONE_THREAD) {
 		/*
-		 * Linux agrees with us: THREAD requires SIGHAND.
-		 * Unlike Linux, we also also require FS and SYSVSEM.
-		 * Also, we decree it to be incompatible with VFORK, as
-		 * I don't want to work out whether that's 100% safe.
+		 * Linux agrees with us: CLONE_THREAD requires
+		 * CLONE_SIGHAND.  Unlike Linux, we also also require
+		 * CLONE_FS and CLONE_SYSVSEM.  Also, we decree it
+		 * to be incompatible with CLONE_VFORK, as I don't
+		 * want to work out whether that's 100% safe.
 		 */
 #define REQUIRED	\
 	(LINUX_CLONE_SIGHAND | LINUX_CLONE_FS | LINUX_CLONE_SYSVSEM)
@@ -102,21 +103,36 @@ linux_sys_clone(p, v, retval)
 		if ((cflags & (REQUIRED | BANNED)) != REQUIRED)
 			return (EINVAL);
 		/*
-		 * Linux says that THREAD means no signal will be
-		 * sent on exit (even if a non-standard signal is
-		 * requested via LINUX_CLONE_CSIGNAL), so pass
+		 * Linux says that CLONE_THREAD means no signal
+		 * will be sent on exit (even if a non-standard
+		 * signal is requested via CLONE_CSIGNAL), so pass
 		 * FORK_NOZOMBIE too.
 		 */
 		flags |= FORK_THREAD | FORK_NOZOMBIE;
 	} else {
-		/* only supported with THREAD */
-		if (cflags & (LINUX_CLONE_FS | LINUX_CLONE_PARENT |
-		    LINUX_CLONE_SYSVSEM))
+		/*
+		 * These are only supported with CLONE_THREAD.  Arguably,
+		 * CLONE_FS should be in this list, because we don't
+		 * support sharing of working directory and root directory
+		 * (chdir + chroot) except via threads.  On the other
+		 * hand, we tie the sharing of umask to the sharing of
+		 * files, so a process that doesn't request CLONE_FS but
+		 * does ask for CLONE_FILES is going to get some of the
+		 * former's effect.  Some programs (e.g., Opera) at least
+		 * _seem_ to work if we let it through, so we'll just
+		 * cross our fingers for now and silently ignore it if
+		 * CLONE_FILES was also requested.
+		 */
+		if (cflags & (LINUX_CLONE_PARENT | LINUX_CLONE_SYSVSEM))
+			return (EINVAL);
+		if ((cflags & (LINUX_CLONE_FS | LINUX_CLONE_FILES)) ==
+		    LINUX_CLONE_FS)
 			return (EINVAL);
 	}
 	/*
 	 * Since we don't support CLONE_PTRACE, the CLONE_UNTRACED
-	 * flag can be silently ignored.
+	 * flag can be silently ignored.  CLONE_DETACHED is always
+	 * ignored by Linux.
 	 */
 
 	sig = cflags & LINUX_CLONE_CSIGNAL;