svn commit: r303988 - head/lib/libc/gen

[Bryan Drewery]

On 8/25/2016 1:55 PM, Ed Schouten wrote:
> Hi Bryan,
> 
> 2016-08-25 19:43 GMT+02:00 Bryan Drewery <bdrewery at freebsd.org>:
>>>> readelf -a /lib/libc.so.7|grep basename
>>>   2149: 0000000000076200   231 FUNC    GLOBAL DEFAULT   11
>>> basename@@FBSD_1.0 (2)
>>>   2514: 0000000000076140   184 FUNC    GLOBAL DEFAULT   11
>>> basename_r@@FBSD_1.2 (4)
> 
> I think the reason for this is that I haven't made any changes to the
> underlying basename() function (yet); only to dirname(). So there is
> no basename at FBSD_1.0. Only basename@@FBSD_1.0 (to indicate it's the
> latest version against we should link).
> 

It only happens with static builds which lack the 1.0 symbol:

> # readelf -a /usr/lib/libc.a|grep basename
> File: /usr/lib/libc.a(basename.o)
>      1: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS /root/git/freebsd/lib/libc/gen/basename.c
>      2: 0000000000000000     8 OBJECT  LOCAL  DEFAULT    5 basename.bname
>      6: 00000000000000c0   231 FUNC    GLOBAL DEFAULT    2 basename
>      7: 0000000000000000   184 FUNC    GLOBAL DEFAULT    2 basename_r

With dynamic it is fine:

> # readelf -a /lib/libc.so.7|grep basename
>   2149: 0000000000078280   231 FUNC    GLOBAL DEFAULT   11 basename@@FBSD_1.0 (2)
>   2514: 00000000000781c0   184 FUNC    GLOBAL DEFAULT   11 basename_r@@FBSD_1.2 (4)


> What happens if you s/__sym_compat/__sym_default the basename() line?
> 
> 

Libc wouldn't build, it complained quite loudly with a lot of these:

> fatal error: error in backend: A @@ version cannot be undefined



With this it built:

> diff --git lib/libc/gen/basename.c lib/libc/gen/basename.c
> index 7e21ca4..5f35613 100644
> --- lib/libc/gen/basename.c
> +++ lib/libc/gen/basename.c
> @@ -66,7 +66,7 @@ basename_r(const char *path, char *bname)
>  }
> 
>  char *
> -basename(char *path)
> +(basename_impl)(char *path)
>  {
>         static char *bname = NULL;
> 
> @@ -77,3 +77,4 @@ basename(char *path)
>         }
>         return (basename_r(path, bname));
>  }
> +__sym_default(basename, basename_impl, FBSD_1.0);

Perhaps there is a better way, but it worked...

Then I get:

> # readelf -a /lib/libc.so.7|grep basename
>   2145: 0000000000078280   231 FUNC    GLOBAL DEFAULT   11 basename@@FBSD_1.0 (2)
>   2514: 00000000000781c0   184 FUNC    GLOBAL DEFAULT   11 basename_r@@FBSD_1.2 (4)
> # readelf -a /usr/lib/libc.a|grep basename
> File: /usr/lib/libc.a(basename.o)
>      1: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS /root/git/freebsd/lib/libc/gen/basename.c
>      2: 0000000000000000     8 OBJECT  LOCAL  DEFAULT    5 basename_impl.bname
>      6: 00000000000000c0   231 FUNC    GLOBAL DEFAULT    2 basename@@FBSD_1.0
>      7: 00000000000000c0   231 FUNC    GLOBAL DEFAULT    2 basename_impl
>      8: 0000000000000000   184 FUNC    GLOBAL DEFAULT    2 basename_r

And xinstall builds with dynamic and static and runs fine.


-- 
Regards,
Bryan Drewery

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