| Message ID | 20170214103353.GA8394@altlinux.org |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
From: "Dmitry V. Levin" <ldv@altlinux.org> Date: Tue, 14 Feb 2017 13:33:53 +0300 > In file included from /usr/include/linux/l2tp.h:12:0, > from /usr/include/linux/if_pppol2tp.h:21, > /usr/include/netinet/in.h:31:8: error: redefinition of 'struct in_addr' This is protected properly by __UAPI_DEF_IN_ADDR, so whichever gets included first makes the definition. This whole thing is designed so that if GLIBC headers are included first, __UAPI_DEF_IN_ADDR will be defined to zero, therefore linux/in.h won't try to make the definition. Otherwise it will. The facility should not be so fragile that we have to play all kinds of header ordering games. We would be imposing the same strange rules on userspace applications including these headers which is completely unacceptable. So if the facility isn't working correctly, let's fix that instead of fidgeting with include ordering all over the tree. Thanks.
On Tue, Feb 14, 2017 at 02:37:23PM -0500, David Miller wrote: > From: "Dmitry V. Levin" <ldv@altlinux.org> > Date: Tue, 14 Feb 2017 13:33:53 +0300 > > > In file included from /usr/include/linux/l2tp.h:12:0, > > from /usr/include/linux/if_pppol2tp.h:21, > > /usr/include/netinet/in.h:31:8: error: redefinition of 'struct in_addr' > > This is protected properly by __UAPI_DEF_IN_ADDR, so whichever gets > included first makes the definition. > > This whole thing is designed so that if GLIBC headers are included > first, __UAPI_DEF_IN_ADDR will be defined to zero, therefore > linux/in.h won't try to make the definition. Otherwise it will. > > The facility should not be so fragile that we have to play all > kinds of header ordering games. We would be imposing the same > strange rules on userspace applications including these headers > which is completely unacceptable. The facility is so fragile that netinet/in.h cannot be included after linux/in.h: $ gcc -S -o/dev/null -xc /dev/null -include /usr/include/linux/in.h -include /usr/include/netinet/in.h In file included from <command-line>:32:0: /usr/include/netinet/in.h:31:8: error: redefinition of 'struct in_addr' struct in_addr ^~~~~~~ In file included from <command-line>:32:0: /usr/include/linux/in.h:84:8: note: originally defined here struct in_addr { ^~~~~~~ > So if the facility isn't working correctly, let's fix that instead > of fidgeting with include ordering all over the tree. I don't mind if the whole facility will get fixed someday. My humble objective was just to fix the regression introduced in v4.10-rc1 by commit 47c3e7783be4.
diff --git a/include/uapi/linux/if_pppol2tp.h b/include/uapi/linux/if_pppol2tp.h index 6418c4d..54a404e 100644 --- a/include/uapi/linux/if_pppol2tp.h +++ b/include/uapi/linux/if_pppol2tp.h @@ -16,9 +16,9 @@ #define _UAPI__LINUX_IF_PPPOL2TP_H #include <linux/types.h> +#include <linux/l2tp.h> #include <linux/in.h> #include <linux/in6.h> -#include <linux/l2tp.h> /* Structure used to connect() the socket to a particular tunnel UDP * socket over IPv4.
Move inclusion of <linux/l2tp.h> before <linux/in.h> to fix userspace compilation errors like this: In file included from /usr/include/linux/l2tp.h:12:0, from /usr/include/linux/if_pppol2tp.h:21, /usr/include/netinet/in.h:31:8: error: redefinition of 'struct in_addr' Fixes: 47c3e7783be4 ("net: l2tp: deprecate PPPOL2TP_MSG_* in favour of L2TP_MSG_*") Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> --- include/uapi/linux/if_pppol2tp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)