Date: Wed, 14 Jun 2006 16:13:53 +0200 From: Bruno Haible <bruno@clisp.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Vasil Dimov <vd@freebsd.org>, hackers@freebsd.org Subject: Re: valid VMA ranges and mincore() Message-ID: <200606141613.54027.bruno@clisp.org> In-Reply-To: <20060614135600.GB86300@deviant.kiev.zoral.com.ua> References: <200606101822.46437.bruno@clisp.org> <200606141404.08811.bruno@clisp.org> <20060614135600.GB86300@deviant.kiev.zoral.com.ua>
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Hello Konstantin,
> > - Filling in values of -1 into the array could be done more easily by
> > changing the statements in sys/vm/vm_mmap.c lines 861 and 902.
> I do not agree. It zeroes array not only for holes, but also for (some)
> skipped vm areas.
ok, you understand the code better than I do :-)
> Index: vm_mmap.c
> ===================================================================
> RCS file: /usr/local/arch/ncvs/src/sys/vm/vm_mmap.c,v
> retrieving revision 1.205
> diff -u -r1.205 vm_mmap.c
> --- vm_mmap.c 21 Apr 2006 07:17:25 -0000 1.205
> +++ vm_mmap.c 14 Jun 2006 13:51:20 -0000
> @@ -756,8 +756,10 @@
> first_addr = addr = trunc_page((vm_offset_t) uap->addr);
> end = addr + (vm_size_t)round_page(uap->len);
> map = &td->td_proc->p_vmspace->vm_map;
> - if (end > vm_map_max(map) || end < addr)
> + if (end < addr)
> return (EINVAL);
> + if (end > vm_map_max(map))
> + return (ENOMEM);
>
> /*
> * Address of byte vector
> @@ -770,8 +772,18 @@
> RestartScan:
> timestamp = map->timestamp;
>
> - if (!vm_map_lookup_entry(map, addr, &entry))
> - entry = entry->next;
> + if (!vm_map_lookup_entry(map, first_addr, &entry)) {
> + vm_map_unlock_read(map);
> + return (ENOMEM);
> + }
> + for (current = entry;
> + (current != &map->header) && (current->end < end);
> + current = current->next) {
> + if (current->end != current->next->start) {
> + vm_map_unlock_read(map);
> + return (ENOMEM);
> + }
> + }
>
> /*
> * Do this on a map entry basis so that if the pages are not
>
Looks good to me: This does what Linux, NetBSD, Solaris do. Thanks!
Bruno
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