Re: [PATCH v2] posix/tst-rfc3484: Fix compile failure linking to local __stat64

[Stafford Horne via Libc-alpha <libc-alpha@sourceware.org>]

On Mon, Jan 25, 2021 at 11:55:43AM -0300, Adhemerval Zanella wrote:
> 
> 
> On 22/01/2021 20:05, Stafford Horne via Libc-alpha wrote:
> > After 04986243d1 ("Remove internal usage of extensible stat functions")
> > linking the __stat64 symbol in getaddrinfo for this test fails with the
> > below error:
> > 
> >     /home/shorne/work/gnu-toolchain/local/lib/gcc/or1k-smh-linux-gnu/11.0.0/../../../../or1k-smh-linux-gnu/bin/ld: /home/shorne/work/gnu-toolchain/build-glibc/posix/tst-rfc3484.o: in function `gaiconf_reload':
> >     /home/shorne/work/gnu-toolchain/glibc/posix/../sysdeps/posix/getaddrinfo.c:2136: undefined reference to `__stat64'
> >     collect2: error: ld returned 1 exit status
> > 
> > This is because __stat64 is a local symbol, the test includes the
> > getaddrinfo directly and fails to link against the local symbol.  Fix
> > this by setting up an alias to the global stat64 symbol name like is
> > done for other local symbol usage.
> 
> I am trying to understand why I haven't see a similar issue for riscv32,
> since it does not provide any xstat symbols.  It seems that for tests,
> I am not seeing any __stat64 call, but rather __fstat64 ones:
> 
>   $ riscv32-glibc-linux-gnu-objdump -t posix/tst-rfc3484.o | grep stat
>   00000000         *UND*  00000000 __fstat64
>   $ riscv32-glibc-linux-gnu-objdump -t posix/tst-rfc3484-2.o | grep stat
>   00000000         *UND*  00000000 __fstat64
>   $ riscv32-glibc-linux-gnu-objdump -t posix/tst-rfc3484-3.o | grep stat
>   00000000         *UND*  00000000 __fstat64
> 
> It comes from gaiconf_init and I am not sure why __stat64 call from
> gaiconf_reload is not being generated (maybe this is being optimized
> out).
> 
> And the __fstat64 seems to not generate a linking error because is being
> exported by libc.so in GLIBC_PRIVATE namespace (due 8ed005daf0ab03). I
> added this because of the libpthread usage, but it seems we don't
> actually required it.  For 2.34 I plan to send:

Thanks for the explaination.  I also wonder why it wasn't showing up in other
platforms.

> diff --git a/io/Versions b/io/Versions
> index 49c4d2d40a..4ffafd4bde 100644
> --- a/io/Versions
> +++ b/io/Versions
> @@ -145,6 +145,5 @@ libc {
>      __file_change_detection_for_stat;
>      __file_change_detection_for_path;
>      __file_change_detection_for_fp;
> -    __fstat64;
>    }
>  }
> diff --git a/sysdeps/pthread/sem_open.c b/sysdeps/pthread/sem_open.c
> index b0b722121d..b3b4de779b 100644
> --- a/sysdeps/pthread/sem_open.c
> +++ b/sysdeps/pthread/sem_open.c
> @@ -68,7 +68,7 @@ check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing)
>  
>    /* Get the information about the file.  */
>    struct stat64 st;
> -  if (__fstat64 (fd, &st) == 0)
> +  if (fstat64 (fd, &st) == 0)
>      {
>        /* Get the lock.  */
>        lll_lock (__sem_mappings_lock, LLL_PRIVATE);
> 
> To remove the __fstat64 requirement on GLIBC_PRIVATE.
> 
> This patch looks ok on 2.34 opens.
> 
> > ---
> > Changes since v1:
> >  - Fix typo in commit s/list/like/
> >  - Address other tests that fail with the same issue
> > 
> >  posix/tst-rfc3484-2.c | 1 +
> >  posix/tst-rfc3484-3.c | 1 +
> >  posix/tst-rfc3484.c   | 1 +
> >  3 files changed, 3 insertions(+)
> > 
> > diff --git a/posix/tst-rfc3484-2.c b/posix/tst-rfc3484-2.c
> > index 5f5ada9420..ce8ccd5f38 100644
> > --- a/posix/tst-rfc3484-2.c
> > +++ b/posix/tst-rfc3484-2.c
> > @@ -11,6 +11,7 @@
> >  #define __gethostbyaddr_r gethostbyaddr_r
> >  #define __gethostbyname2_r gethostbyname2_r
> >  #define __qsort_r qsort_r
> > +#define __stat64 stat64
> >  
> >  void
> >  attribute_hidden
> > diff --git a/posix/tst-rfc3484-3.c b/posix/tst-rfc3484-3.c
> > index d9ec5cc851..ecb163963f 100644
> > --- a/posix/tst-rfc3484-3.c
> > +++ b/posix/tst-rfc3484-3.c
> > @@ -11,6 +11,7 @@
> >  #define __gethostbyaddr_r gethostbyaddr_r
> >  #define __gethostbyname2_r gethostbyname2_r
> >  #define __qsort_r qsort_r
> > +#define __stat64 stat64
> >  
> >  void
> >  attribute_hidden
> > diff --git a/posix/tst-rfc3484.c b/posix/tst-rfc3484.c
> > index 97d065b6bf..3b2052eb54 100644
> > --- a/posix/tst-rfc3484.c
> > +++ b/posix/tst-rfc3484.c
> > @@ -11,6 +11,7 @@
> >  #define __gethostbyaddr_r gethostbyaddr_r
> >  #define __gethostbyname2_r gethostbyname2_r
> >  #define __qsort_r qsort_r
> > +#define __stat64 stat64
> >  
> >  void
> >  attribute_hidden
> >