diff options
| author | itojun <itojun@NetBSD.org> | 2000-03-02 07:41:49 +0000 |
|---|---|---|
| committer | itojun <itojun@NetBSD.org> | 2000-03-02 07:41:49 +0000 |
| commit | 2dc247fc34ed0fd256fd948c164aa2c3d2ba491f (patch) | |
| tree | 49f0f5d8f5da31dd50a71c1f5a4931a542c3df09 /lib/libc/net/__cmsg_alignbytes.c | |
| parent | 52c11b789af6bb4701f8231be6ec6bbe18ce88c2 (diff) | |
make CMSG_ALIGN always synchronize with kernel's idea of ALIGNBYTES.
ancillary data alignment will be ALIGNBYTES, not sizeof(long) - 1, from now.
CMSG_xx will NOT resolve into constant. if you use CMSG_xx to allocate
arrays, you'll lose.
bump shlib minor for libc.
NOTE: if you are on top of arch with ALIGNBYTES != sizeof(long) - 1,
you need to recompile IPv6-related binaries. there is no way to guarantee
backward compat in this aspect. sorry for this. this should be the last
backward compat breakage for IPv6-related ancillary data manipulation.
(we still have PR 9516 for unix-domain sockets...)
Diffstat (limited to 'lib/libc/net/__cmsg_alignbytes.c')
| -rw-r--r-- | lib/libc/net/__cmsg_alignbytes.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/lib/libc/net/__cmsg_alignbytes.c b/lib/libc/net/__cmsg_alignbytes.c new file mode 100644 index 00000000000..594d34c8882 --- /dev/null +++ b/lib/libc/net/__cmsg_alignbytes.c @@ -0,0 +1,65 @@ +/* $NetBSD: __cmsg_alignbytes.c,v 1.1 2000/03/02 07:41:52 itojun Exp $ */ + +/*- + * Copyright (c) 2000 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Jun-ichiro Hagino. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of The NetBSD Foundation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <sys/param.h> +#include <sys/sysctl.h> +#include <sys/socket.h> + +int +__cmsg_alignbytes() +{ + static int alignbytes = -1; +#ifdef HW_ALIGNBYTES + int mib[2]; + size_t len; + int ret; +#endif + + if (alignbytes > 0) + return alignbytes; + +#ifdef HW_ALIGNBYTES + mib[0] = CTL_HW; + mib[1] = HW_ALIGNBYTES; + len = sizeof(alignbytes); + ret = sysctl(mib, sizeof(mib)/sizeof(mib[0]), (void *)&alignbytes, + &len, NULL, 0); + if (ret >= 0 && alignbytes >= 0) + return alignbytes; +#endif + /* last resort */ + alignbytes = ALIGNBYTES; + return alignbytes; +} |
