[PATCH] fix msghdr for 64bit platform (Was: status of 0.9.29)
Atsushi Nemoto
anemo at mba.ocn.ne.jp
Thu Oct 26 15:36:19 UTC 2006
On Wed, 18 Oct 2006 13:57:45 +0900 (JST), Atsushi Nemoto <anemo at mba.ocn.ne.jp> wrote:
> It looks due to mismatch of struct msghdr.
...
> On 64-bit environment, the size of msg_namelen seems 4 for all, but
> the size of msg_iovlen and msg_controllen is 8 for kernel and glibc, 4
> for uClibc.
>
> If I copied struct msghdr from glibc, "ip addr" works well.
>
> But, there is a note in libc/sysdeps/linux/common/bits/socket.h.
>
> /* Note: do not change these members to match glibc; these match the
> SuSv3 spec already (e.g. msg_iovlen/msg_controllen).
> http://www.opengroup.org/onlinepubs/009695399/basedefs/sys/socket.h.html */
>
> Then ... what should we do?
Then how about attached patch? It would solve the problem on 64-bit
platforms.
Or we might be able to do something like this and make
sendmsg/recvmsg wrappers which clear zeropad fields, but I think it is
not worth to do so ...
#if __WORDSIZE == 64 && __BYTE_ORDER == __BIG_ENDIAN
int zeropad;
#endif
int msg_iovlen; /* Number of elements in the vector. */
#if __WORDSIZE == 64 && __BYTE_ORDER == __LITTLE_ENDIAN
int zeropad;
#endif
---
Atsushi Nemoto
-------------- next part --------------
Index: libc/sysdeps/linux/common/bits/socket.h
===================================================================
--- libc/sysdeps/linux/common/bits/socket.h (revision 16441)
+++ libc/sysdeps/linux/common/bits/socket.h (working copy)
@@ -215,16 +215,26 @@
/* Note: do not change these members to match glibc; these match the
SuSv3 spec already (e.g. msg_iovlen/msg_controllen).
http://www.opengroup.org/onlinepubs/009695399/basedefs/sys/socket.h.html */
+/* Note: but linux kernel use __kernel_size_t (which is 8byte on 64bit
+ platforms) for msg_iovlen/msg_controllen */
struct msghdr
{
void *msg_name; /* Address to send to/receive from. */
socklen_t msg_namelen; /* Length of address data. */
struct iovec *msg_iov; /* Vector of data to send/receive into. */
+#if __WORDSIZE == 64
+ size_t msg_iovlen; /* Number of elements in the vector. */
+#else
int msg_iovlen; /* Number of elements in the vector. */
+#endif
void *msg_control; /* Ancillary data (eg BSD filedesc passing). */
+#if __WORDSIZE == 64
+ size_t msg_controllen; /* Ancillary data buffer length. */
+#else
socklen_t msg_controllen; /* Ancillary data buffer length. */
+#endif
int msg_flags; /* Flags on received message. */
};
Index: libc/sysdeps/linux/mips/bits/socket.h
===================================================================
--- libc/sysdeps/linux/mips/bits/socket.h (revision 16441)
+++ libc/sysdeps/linux/mips/bits/socket.h (working copy)
@@ -219,10 +219,18 @@
socklen_t msg_namelen; /* Length of address data. */
struct iovec *msg_iov; /* Vector of data to send/receive into. */
+#if __WORDSIZE == 64
+ size_t msg_iovlen; /* Number of elements in the vector. */
+#else
int msg_iovlen; /* Number of elements in the vector. */
+#endif
void *msg_control; /* Ancillary data (eg BSD filedesc passing). */
+#if __WORDSIZE == 64
+ size_t msg_controllen; /* Ancillary data buffer length. */
+#else
socklen_t msg_controllen; /* Ancillary data buffer length. */
+#endif
int msg_flags; /* Flags on received message. */
};
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