Re: configure issue: getfsstat(), 'struct statfs' and 'struct fsstat'

[Bernhard Voelker]

[forwarding to gnulib]

On 07/11/2018 02:00 PM, Barath Aron wrote:
> Hello,
> 
> I have a little issue around the detection of the getfsstat() function.
> 
> According to multiple manuals from different BSD versions [1,2], the 
> signature of the BSD's getfsstat() is this:
> int getfsstat(struct statfs *buf, long bufsize, int mode);
> 
> Note, it refers to 'struct statfs'. The statfs structure contains a 
> field that will be interesting in the following [3,4]:
> 
> struct statfs {
> ...
> char      f_fstypename[MFSNAMELEN]; /* filesystem type name */
> ...
> };
> 
> The configure script tries to detect the getfsstat() function but 
> failes, because:
> configure:31706: checking for struct fsstat.f_fstypename
> configure:31706: /path/to/some-cross-gcc -c   conftest.c >&5
___________________^^^^^^^^^^^^^^^^^^^^^^^

What environment did you use?

> conftest.c: In function 'main':
> conftest.c:473:22: error: storage size of 'ac_aggr' isn't known
>   static struct fsstat ac_aggr;
>                        ^~~~~~~
> configure:31706: $? = 1
> configure: failed program was:
> | /* confdefs.h */
> | #define PACKAGE_NAME "GNU findutils"
> | #define PACKAGE_TARNAME "findutils"
> | #define PACKAGE_VERSION "4.6.0"
> ...
> | int
> | main ()
> | {
> | static struct fsstat ac_aggr;
> | if (ac_aggr.f_fstypename)
> | return 0;
> |   ;
> |   return 0;
> | }
> 
> However, the used type in the failed program was 'struct fsstat'. By the 
> definition of 'struct statfs' found in the BSD manuals, does have a 
> field 'f_fstypename'. But the name is different.
> 
> My goal is to compile the findutils by supplying the BSD's getfsstat() 
> API to get mountlist. For now, I do not want to implement the Linux's 
> <mntent.h> stuff, I like the BSD approach.
> 
> So, my questions are:
> a) Why the configure use a different type name?
> b) If it is intentional, then where that type is defined? Unfortunately, 
> I did not found anything.
> c) Is this branch of the configure still maintained, or it is abandoned? 
> The related code that use this API is also still maintained?
> 
> Aron
> 
> [1] https://man.openbsd.org/getfsstat.2
> [2] https://www.freebsd.org/cgi/man.cgi?query=getfsstat&sektion=2
> [3] https://man.openbsd.org/statfs.2
> [4] https://www.freebsd.org/cgi/man.cgi?query=statfs&sektion=2

These seem to be questions for upstream gnulib.

Have a nice day,
Berny