[Bug stdio/28099] New: fcloseall doesn't close anything

[Bug stdio/28099] New: fcloseall doesn't close anything

[crrodriguez at opensuse dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28099

            Bug ID: 28099
           Summary: fcloseall doesn't close anything
           Product: glibc
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: stdio
          Assignee: unassigned at sourceware dot org
          Reporter: crrodriguez at opensuse dot org
  Target Milestone: ---

Example to demonstrate de bug.

#define _GNU_SOURCE
#include <stdio.h>
#include <assert.h>

int main(void)
{
    FILE *fp, *fp1;
    fp = tmpfile();
    fp1 =tmpfile();
    assert ( fcloseall() == 0 );
    assert ( fputs("doh", fp) < 0 );
    assert ( fputs("bla", fp1) < 0 );
    return 0;
}

after the fcloseall() call all writes to the stream must fail..it really does
not appear to be doing anything.

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[Bug stdio/28099] fcloseall doesn't close anything

[schwab@linux-m68k.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28099

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
There is no way to find out because any use of any FILE pointer after fcloseall
is undefined.

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[Bug stdio/28099] fcloseall doesn't close anything

[crrodriguez at opensuse dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28099

--- Comment #2 from Cristian Rodríguez <crrodriguez at opensuse dot org> ---
(In reply to Andreas Schwab from comment #1)
> There is no way to find out because any use of any FILE pointer after
> fcloseall is undefined.

yes, I guess I wrote the wrong test.. :-) my point is that fcloseall() is not
closing streams, at least it is not doing what the manual says..

"This function causes all open streams of the process to be closed and the
connections to corresponding files to be broken." the streams are NOT
closed..fds are not closed either.

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[Bug stdio/28099] fcloseall doesn't close anything

[infor at rudhar dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28099

Ruud Harmsen <infor at rudhar dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |infor at rudhar dot com

--- Comment #3 from Ruud Harmsen <infor at rudhar dot com> ---
Or perhaps the streams and file descriptors ARE closed, but fputs error
checking isn't working properly? Cf.
https://sourceware.org/bugzilla/show_bug.cgi?id=20632, where I found the first
fputws to a closed stderr (that is, a close(2) was done) does return -1, as it
should, but subsequent calls of  fputws return 1 as if they are OK. But they
aren't, no text appears.

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[Bug stdio/28099] fcloseall doesn't close anything

[crrodriguez at opensuse dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28099

--- Comment #4 from Cristian Rodríguez <crrodriguez at opensuse dot org> ---
(In reply to Ruud Harmsen from comment #3)
> Or perhaps the streams and file descriptors ARE closed, but fputs error
> checking isn't working properly? Cf.
> https://sourceware.org/bugzilla/show_bug.cgi?id=20632, where I found the
> first fputws to a closed stderr (that is, a close(2) was done) does return
> -1, as it should, but subsequent calls of  fputws return 1 as if they are
> OK. But they aren't, no text appears.

In my test, file descriptors are not closed by a call to fcloseall()

Andreas is entirely right that doing anything with fp and fp1 after fcloseall()
is UB. (it woould be incredible nice to get an error/assertion/fortify_fail or
whatever in that case but that is again not required by anything) however when
I tested nothing was closed in the first place.

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[Bug stdio/28099] fcloseall doesn't close anything

[crrodriguez at opensuse dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28099

--- Comment #5 from Cristian Rodríguez <crrodriguez at opensuse dot org> ---
expectation : fcloseall() sorts all file descriptors associated with FILE* s in
the current thread, calls close_range(2) on them..

..and maybe..just maybe add a warning attribute to the function discouraging
people to use it..

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