[uclibc-ng-devel] [PATCH] Fix header installation for recent 64-only arch

Summary: Recent arch do not support Legacy. Thus they don't define ARCH_HAS_DEPRECATED_SYSCALLS But this led to per-arch headers not being installed and common-generic ones taking precedence. So it was impossible to declare arch-specific statfs.h for instance, to force 64-bit mode only. This was leading to the following situation to happen: 1/ an application compiles (say without -D_FILE_OFFSET_BITS set) it therefore uses struct statfs from libc/sysdeps/linux/common-generic/bits/statfs.h where f_type and f_bsize fields are U32: https://elixir.bootlin.com/uclibc-ng/latest/source/libc/sysdeps/linux/commo… 2/ application calls "statfs" 3/ uClibc issues "statfs64" syscall (because __NR_statfs64 is defined and __NR_statfs is undefined): https://elixir.bootlin.com/uclibc-ng/latest/source/libc/sysdeps/linux/commo… 4/ if Linux kernel port is not defining CONFIG_COMPAT, it calls do_statfs_native https://elixir.bootlin.com/linux/latest/source/fs/statfs.c#L195 5/ it does copy_to_user of the size of struct statfs defined in the kernel source tree: https://elixir.bootlin.com/linux/latest/source/fs/statfs.c#L161 6/ Generic struct statfs in the kernel is defined like this: https://elixir.bootlin.com/linux/latest/source/include/uapi/asm-generic/sta… f_type and f_bsize fields are long (64 bits) for 64-bit archs. 7/ memory corruption occurs because of this mismatch Solution: Allow to not define __ARCH_HAS_DEPRECATED_SYSCALLS__ *and* declare its own arch-specific statfs.h header, matching the kernel one. (for instance with f_type and f_bsize defined as long) Does this change break other archs? This change allows headers in libc/sysdeps/linux/<ARCH>/bits/ to override ones in libc/sysdeps/linux/common-generic/bits/ The only arch which does not define __ARCH_HAS_DEPRECATED_SYSCALLS__ *and* has a header in libc/sysdeps/linux/<ARCH>/bits/ which can conflict with one in libc/sysdeps/linux/common-generic/bits/ is c6x. The file that can override is ../libc/sysdeps/linux/c6x/bits/kernel_stat.h This, btw, means that, today, this file is there and is not used (during compilation, GNU Make overrides the rule): Makefile.in:152: warning: overriding recipe for target `include/bits/kernel_stat.h' Makefile.in:148: warning: ignoring old recipe for target `include/bits/kernel_stat.h' I was not able to compile uClibc with the only binary toolchain I found for c6x arch (gcc-4.5.1 from code sourcery: https://sourcery.mentor.com/GNUToolchain/release1882) However, I can tell that c6x's kernel_stat.h only defines two structs: kernel_stat and kernel_stat64: https://elixir.bootlin.com/uclibc-ng/latest/source/libc/sysdeps/linux/c6x/b… And I can also tell that those structs are only used when using xstat conversion functions (__xstat32_conv / xstat_conv) which are only used and present in the __ARCH_HAS_DEPRECATED_SYSCALLS__ == y case. However, c6x does not define __ARCH_HAS_DEPRECATED_SYSCALLS__ So I think I can say that this change does not affect c6x nor other archs. --- Makefile.in | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/Makefile.in b/Makefile.in index 1754040..16ee9ee 100644 --- a/Makefile.in +++ b/Makefile.in @@ -144,14 +144,14 @@ $(top_builddir)include/dl-osinfo.h $(top_builddir)include/not-cancel.h: $(ALL_HEADERS_BITS_COMMON): $(do_ln) $(call rel_srcdir)libc/sysdeps/linux/common/bits/$(@F) $@ -$(ALL_HEADERS_BITS_ARCH): - $(do_ln) $(call rel_srcdir)libc/sysdeps/linux/$(TARGET_ARCH)/bits/$(@F) $@ - ifneq ($(ARCH_HAS_DEPRECATED_SYSCALLS),y) $(ALL_HEADERS_BITS_COMMON_NO_LEGACY): $(do_ln) $(call rel_srcdir)libc/sysdeps/linux/common-generic/bits/$(@F) $@ endif +$(ALL_HEADERS_BITS_ARCH): + $(do_ln) $(call rel_srcdir)libc/sysdeps/linux/$(TARGET_ARCH)/bits/$(@F) $@ + ifneq ($(TARGET_SUBARCH),) $(ALL_HEADERS_BITS_SUBARCH): $(do_ln) $(call rel_srcdir)libc/sysdeps/linux/$(TARGET_ARCH)/bits/$(TARGET_SUBARCH)/$(@F) $@ -- 1.8.3.1