After committing the new MNT_NOPERM flag I got some complaints that my
code doesn't work by people that recompiled mount_ffs, but didn't reboot
to the new kernel. I don't blame them; in that situation sys_mount()
silently ignores the unknown flag. IMHO we should check the flags more
strictly. Ok?
natano
Index: sys/mount.h
===================================================================
RCS file: /cvs/src/sys/sys/mount.h,v
retrieving revision 1.127
diff -u -p -r1.127 mount.h
--- sys/mount.h 10 Sep 2016 16:53:30 -0000 1.127
+++ sys/mount.h 1 Oct 2016 15:36:11 -0000
@@ -414,6 +414,11 @@ struct mount {
#define MNT_DOOMED 0x08000000 /* device behind filesystem is gone */
/*
+ * All mount flags.
+ */
+#define MNT_FLAGMASK 0x0e0fffff
+
+/*
* Flags for various system call interfaces.
*
* waitfor flags to vfs_sync() and getfsstat()
Index: kern/vfs_syscalls.c
===================================================================
RCS file: /cvs/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.265
diff -u -p -r1.265 vfs_syscalls.c
--- kern/vfs_syscalls.c 10 Sep 2016 16:53:30 -0000 1.265
+++ kern/vfs_syscalls.c 1 Oct 2016 15:36:11 -0000
@@ -117,6 +117,9 @@ sys_mount(struct proc *p, void *v, regis
if ((error = suser(p, 0)))
return (error);
+ if (flags & ~MNT_FLAGMASK)
+ return (EINVAL);
+
/*
* Mount points must fit in MNAMELEN, not MAXPATHLEN.
*/
