[PATCH 2/7] utimes: Export utimensat based utimes

[Markos Chandras]

On 11 March 2013 13:21, Vineet Gupta <Vineet.Gupta1 at synopsys.com> wrote:
> sys/time.h has libc_hidden_proto(utimes) which generates the hidden
> "__GI_utimes" symbol reference, and common/utimes.c has a
> libc_hidden_def(utimes) which generates the exported "utimes" alias.
>
> As part of no-legacy-syscall kernel ABI, Commit 80dc2ed05
> "utimes: Use utimensat if arch does not have the utimes syscall"
> introduced a new wrapper, but missed the corresponding libc_hidden_def,
> causing Busybox (1.20.0) link to fail (for ARC).
>
> ---------------->8-------------------
> ....
> touch.c:(.text.touch_main+0xdc): undefined reference to `utimes'
> touch.c:(.text.touch_main+0x114): undefined reference to `utimes'
> libbb/lib.a(copy_file.o): In function `copy_file':
> copy_file.c:(.text.copy_file+0x446): undefined reference to `utimes'
> collect2: ld returned 1 exit status
> ---------------->8-------------------
>
> Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
> Cc: Markos Chandras <markos.chandras at imgtec.com>
> ---
>  libc/sysdeps/linux/common/utimes.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/libc/sysdeps/linux/common/utimes.c b/libc/sysdeps/linux/common/utimes.c
> index a459d15..b5e76cc 100644
> --- a/libc/sysdeps/linux/common/utimes.c
> +++ b/libc/sysdeps/linux/common/utimes.c
> @@ -51,6 +51,6 @@ int utimes(const char *file, const struct timeval tvp[2])
>  }
>  #endif
>
> -#if defined __NR_utimes || defined __NR_utime
> +#if defined __NR_utimensat || defined __NR_utimes || defined __NR_utime
>  libc_hidden_def(utimes)
>  #endif
> --
> 1.7.4.1
>
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Well, yeah your fix is correct but the linking problem is not because
we don't have libc_hidden_def(utimes) for new arches. You most likely
build uClibc without __UCLIBC_HAS_STUBS__ and this is why you are
seeing the linking problems. We currently have the following code in
libc/sysdeps/linux/common/stubs.c

#if !defined __NR_utime && !defined __NR_utimes
/*make_stub(utime) obsoleted */
make_stub(utimes)
#endif

So, if __UCLIBC_HAS_STUBS__ is enabled, you will have a utimes symbol
in your libc but it will actually return ENOSYS. So whilst we provide
a utimes function for new architectures, we never actually use it and
we create a stub instead. This is wrong so I believe your patch needs
to fix the libc/sysdeps/linux/common/stubs.c entry as well.

-- 
Regards,
Markos Chandras