[ptxdist] 32 or 64 bits file offsets?

[ptxdist] 32 or 64 bits file offsets?

[Felix Mellmann]

Hello,

I'm currently investigating, why SVN (subversion) does not work properly 
when built for ptxdist. (At first curious segfault, now corrupt data)

I came to this thread:
https://groups.google.com/forum/#!topic/subversion_users/QX91S90YvWk
which is quite the same, that happens to me.

If I'm looking into ptxconfig I find
PTXCONF_GLOBAL_LARGE_FILE=y
In my opinion, this means, that 64 bit file offsets are used.

Now, if I run a program which checks the sizes of the types off_t, size_t 
and ssize_t:

#include <stdio.h>
#include <sys/types.h>
#include <sys/uio.h>

int main(void)
{
    off_t off;
    size_t size;
    ssize_t ssize;
    struct iovec io_vec;

    printf("sizeof(off_t)=%ld\n", sizeof(off));
    printf("sizeof(size_t)=%ld\n", sizeof(size_t));
    printf("sizeof(ssize_t)=%ld\n", sizeof(ssize_t));
    printf("sizeof(struct iovec)=%ld\n", sizeof(struct iovec));

    return 0;
}

the program returns 4 for off_t, size_t and ssize_t and 8 for struct iovec.

But 4 bytes * 8 bit/byte gives 32 bit.

Could someone please explain me, where I am wrong?

I already tried to recompile my project with GLOBAL_LARGE_FILE disabled, but 
without any success for subversion.

Thank you a lot,

Felix


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Re: [ptxdist] 32 or 64 bits file offsets?

[Bernhard Walle]

* Felix Mellmann <felix.mellmann@googlemail.com> [2013-12-07 17:47]:
> 
> If I'm looking into ptxconfig I find
> PTXCONF_GLOBAL_LARGE_FILE=y
> In my opinion, this means, that 64 bit file offsets are used.

No, not in general. This flag "just" sets --enable-lfs or
--enable-largefile as configure option for programs that support it.
Grep for 'PTXCONF_GLOBAL_LARGE_FILE' and 'GLOBAL_LARGE_FILE_OPTION'.

It doesn't set compile flags directly.

Regards,
Bernhard

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Re: [ptxdist] 32 or 64 bits file offsets?

[Felix Mellmann]

Bernhard Walle <bernhard@...> writes:

> No, not in general. This flag "just" sets --enable-lfs or
> --enable-largefile as configure option for programs that support it.
> Grep for 'PTXCONF_GLOBAL_LARGE_FILE' and 'GLOBAL_LARGE_FILE_OPTION'.
> 
> It doesn't set compile flags directly.

D'oh! But your clue was the right direction.
The problem lies in how apr (Apache Portable Runtime) detects how to use 
large file support. On the one hand side it detects, that additional CFLAGS 
are not needed on the other hand side it detects, that off_t should be 
redefined as off64_t (which is ok for my x86-64 machine).

As I'm using apr-1.4.8 instead of current shipped apr-0.9.20, I'm going to 
investigate, if this happens also to apr-0.9.20.
If so, I would post a patch. This patch should include selectable large file 
support as well?

Felix



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Re: [ptxdist] 32 or 64 bits file offsets?

[Michael Olbrich]

On Sun, Dec 08, 2013 at 08:14:37AM +0000, Felix Mellmann wrote:
> Bernhard Walle <bernhard@...> writes:
> > No, not in general. This flag "just" sets --enable-lfs or
> > --enable-largefile as configure option for programs that support it.
> > Grep for 'PTXCONF_GLOBAL_LARGE_FILE' and 'GLOBAL_LARGE_FILE_OPTION'.
> > 
> > It doesn't set compile flags directly.
> 
> D'oh! But your clue was the right direction.
> The problem lies in how apr (Apache Portable Runtime) detects how to use 
> large file support. On the one hand side it detects, that additional CFLAGS 
> are not needed on the other hand side it detects, that off_t should be 
> redefined as off64_t (which is ok for my x86-64 machine).
> 
> As I'm using apr-1.4.8 instead of current shipped apr-0.9.20, I'm going to 
> investigate, if this happens also to apr-0.9.20.
> If so, I would post a patch. This patch should include selectable large file 
> support as well?

Don't add an extra option. Just use PTXCONF_GLOBAL_LARGE_FILE.

Michael

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Re: [ptxdist] 32 or 64 bits file offsets?

[Felix Mellmann]

Michael Olbrich <m.olbrich@...> writes:

> 
> 
> Don't add an extra option. Just use PTXCONF_GLOBAL_LARGE_FILE.
> 
> Michael
> 

At last, I didn't investigate on how to enable proper large file support for
Apache Portable Runtime (apr), but I'd like to suggest a patch which will
override sizeof(off_t) to be in line with sizeof(size_t). In case of a 64
bit cross compiling host, sizeof(off_t) will lead to a value of 8 instead of 4.

In my particular case, using subversion (svn) fails with unexpected errors.
Since APR is used by apache webserver as well, modifing sizeof(off_t) will
also have an effect on apache but this is untested.

The maintainers may add my address and name as signed-off.

Regards,
Felix

diff -urdN ptxdist-2013.12.0/rules/apr.make
ptxdist-2013.12.0.debugged/rules/apr.make
--- ptxdist-2013.12.0/rules/apr.make    2013-12-18 10:48:42.000000000 +0100
+++ ptxdist-2013.12.0.debugged/rules/apr.make   2013-12-26
20:05:11.205107001 +0100
@@ -32,6 +32,7 @@
 APR_CONF_ENV := \
        $(CROSS_ENV) \
        ac_cv_file__dev_zero=yes \
+       ac_cv_sizeof_off_t=4 \
        ac_cv_sizeof_size_t=4 \
        ac_cv_sizeof_ssize_t=4 \
        ac_cv_struct_rlimit=yes \




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