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As in UVM, automatically convert MAP_PRIVATE device mappings to MAP_SHARED.

This commit is contained in:
mycroft 1998-03-03 14:35:26 +00:00
parent 24e6e6a0e7
commit 112daacfa3
1 changed files with 18 additions and 1 deletions
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19
sys/vm/vm_mmap.c
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@ -1,4 +1,4 @@
/* $NetBSD: vm_mmap.c,v 1.54 1998/03/01 02:24:01 fvdl Exp $ */
/* $NetBSD: vm_mmap.c,v 1.55 1998/03/03 14:35:26 mycroft Exp $ */
/*
* Copyright (c) 1988 University of Utah.
@ -231,6 +231,23 @@ sys_mmap(p, v, retval)
flags |= MAP_ANON;
goto is_anon;
}
/*
* Old programs may not select a specific sharing type, so
* default to an appropriate one.
*/
if ((flags & (MAP_SHARED|MAP_PRIVATE|MAP_COPY)) == 0) {
if (vp->v_type == VCHR)
flags |= MAP_SHARED; /* for a device */
else
flags |= MAP_PRIVATE; /* for a file */
}
/*
* MAP_PRIVATE device mappings don't make sense (and aren't
* supported anyway). However, some programs rely on this,
* so just change it to MAP_SHARED.
*/
if (vp->v_type == VCHR && (flags & MAP_PRIVATE) != 0)
flags = (flags & ~MAP_PRIVATE) | MAP_SHARED;
/*
* Ensure that file and memory protections are
* compatible. Note that we only worry about