| Message ID | 20180212225951.24708-1-hauke@hauke-m.de |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | uapi/if_ether.h: move __UAPI_DEF_ETHHDR libc define | expand |
On 02/12/2018 11:59 PM, Hauke Mehrtens wrote: > This fixes a compile problem of some user space applications by not > including linux/libc-compat.h in uapi/if_ether.h. > > linux/libc-compat.h checks which "features" the header files, included > from the libc, provide to make the Linux kernel uapi header files only > provide no conflicting structures and enums. If a user application mixes > kernel headers and libc headers it could happen that linux/libc-compat.h > gets included too early where not all other libc headers are included > yet. Then the linux/libc-compat.h would not prevent all the > redefinitions and we run into compile problems. > This patch removes the include of linux/libc-compat.h from > uapi/if_ether.h to fix the recently introduced case, but not all as this > is more or less impossible. > > It is no problem to do the check directly in the if_ether.h file and not > in libc-compat.h as this does not need any fancy glibc header detection > as glibc never provided struct ethhdr and should define > __UAPI_DEF_ETHHDR by them self when they will provide this. > > The following test program did not compile correctly any more: > > int main(void) > { > return 0; > } git removed the included here: #include <linux/if_ether.h> #include <netinet/in.h> #include <linux/in.h> int main(void) { return 0; }
From: Hauke Mehrtens <hauke@hauke-m.de> Date: Tue, 13 Feb 2018 00:01:26 +0100 > On 02/12/2018 11:59 PM, Hauke Mehrtens wrote: >> This fixes a compile problem of some user space applications by not >> including linux/libc-compat.h in uapi/if_ether.h. >> >> linux/libc-compat.h checks which "features" the header files, included >> from the libc, provide to make the Linux kernel uapi header files only >> provide no conflicting structures and enums. If a user application mixes >> kernel headers and libc headers it could happen that linux/libc-compat.h >> gets included too early where not all other libc headers are included >> yet. Then the linux/libc-compat.h would not prevent all the >> redefinitions and we run into compile problems. >> This patch removes the include of linux/libc-compat.h from >> uapi/if_ether.h to fix the recently introduced case, but not all as this >> is more or less impossible. >> >> It is no problem to do the check directly in the if_ether.h file and not >> in libc-compat.h as this does not need any fancy glibc header detection >> as glibc never provided struct ethhdr and should define >> __UAPI_DEF_ETHHDR by them self when they will provide this. >> >> The following test program did not compile correctly any more: >> >> int main(void) >> { >> return 0; >> } > > git removed the included here: > > #include <linux/if_ether.h> > #include <netinet/in.h> > #include <linux/in.h> > > int main(void) > { > return 0; > } Applied with this fixed up, thanks!
On Tue, Feb 13, 2018 at 11:24:07AM -0500, David Miller wrote: > From: Hauke Mehrtens <hauke@hauke-m.de> > Date: Tue, 13 Feb 2018 00:01:26 +0100 > > > On 02/12/2018 11:59 PM, Hauke Mehrtens wrote: > >> This fixes a compile problem of some user space applications by not > >> including linux/libc-compat.h in uapi/if_ether.h. > >> > >> linux/libc-compat.h checks which "features" the header files, included > >> from the libc, provide to make the Linux kernel uapi header files only > >> provide no conflicting structures and enums. If a user application mixes > >> kernel headers and libc headers it could happen that linux/libc-compat.h > >> gets included too early where not all other libc headers are included > >> yet. Then the linux/libc-compat.h would not prevent all the > >> redefinitions and we run into compile problems. > >> This patch removes the include of linux/libc-compat.h from > >> uapi/if_ether.h to fix the recently introduced case, but not all as this > >> is more or less impossible. > >> > >> It is no problem to do the check directly in the if_ether.h file and not > >> in libc-compat.h as this does not need any fancy glibc header detection > >> as glibc never provided struct ethhdr and should define > >> __UAPI_DEF_ETHHDR by them self when they will provide this. > >> > >> The following test program did not compile correctly any more: > >> > >> int main(void) > >> { > >> return 0; > >> } > > > > git removed the included here: > > > > #include <linux/if_ether.h> > > #include <netinet/in.h> > > #include <linux/in.h> > > > > int main(void) > > { > > return 0; > > } > > Applied with this fixed up, thanks! Works fine. Thanks Hauke!
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h index f8cb5760ea4f..8bbbcb5cd94b 100644 --- a/include/uapi/linux/if_ether.h +++ b/include/uapi/linux/if_ether.h @@ -23,7 +23,6 @@ #define _UAPI_LINUX_IF_ETHER_H #include <linux/types.h> -#include <linux/libc-compat.h> /* * IEEE 802.3 Ethernet magic constants. The frame sizes omit the preamble @@ -151,6 +150,11 @@ * This is an Ethernet frame header. */ +/* allow libcs like musl to deactivate this, glibc does not implement this. */ +#ifndef __UAPI_DEF_ETHHDR +#define __UAPI_DEF_ETHHDR 1 +#endif + #if __UAPI_DEF_ETHHDR struct ethhdr { unsigned char h_dest[ETH_ALEN]; /* destination eth addr */ diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h index fc29efaa918c..8254c937c9f4 100644 --- a/include/uapi/linux/libc-compat.h +++ b/include/uapi/linux/libc-compat.h @@ -264,10 +264,4 @@ #endif /* __GLIBC__ */ -/* Definitions for if_ether.h */ -/* allow libcs like musl to deactivate this, glibc does not implement this. */ -#ifndef __UAPI_DEF_ETHHDR -#define __UAPI_DEF_ETHHDR 1 -#endif - #endif /* _UAPI_LIBC_COMPAT_H */
This fixes a compile problem of some user space applications by not including linux/libc-compat.h in uapi/if_ether.h. linux/libc-compat.h checks which "features" the header files, included from the libc, provide to make the Linux kernel uapi header files only provide no conflicting structures and enums. If a user application mixes kernel headers and libc headers it could happen that linux/libc-compat.h gets included too early where not all other libc headers are included yet. Then the linux/libc-compat.h would not prevent all the redefinitions and we run into compile problems. This patch removes the include of linux/libc-compat.h from uapi/if_ether.h to fix the recently introduced case, but not all as this is more or less impossible. It is no problem to do the check directly in the if_ether.h file and not in libc-compat.h as this does not need any fancy glibc header detection as glibc never provided struct ethhdr and should define __UAPI_DEF_ETHHDR by them self when they will provide this. The following test program did not compile correctly any more: int main(void) { return 0; } Fixes: 6926e041a892 ("uapi/if_ether.h: prevent redefinition of struct ethhdr") Reported-by: Guillaume Nault <g.nault@alphalink.fr> Cc: <stable@vger.kernel.org> # 4.15 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> --- include/uapi/linux/if_ether.h | 6 +++++- include/uapi/linux/libc-compat.h | 6 ------ 2 files changed, 5 insertions(+), 7 deletions(-)