Re: fpathconf returns 127 on error

[Andreas Jaeger]

Nathan Straz <address@hidden> writes:

> I'm doing some NEGATIVE testing on fpathconf() and I don't believe what
> I'm seeing.  Instead of getting -1 returned, I get 127.  The man pages,
> the info pages, and the source all say that -1 should be returned.
> Below is a small test program that shows the type of thing I am trying.
> Calling pathconf() with a non-existent path also returns 127.  
> 
> I've tried this program on i386 and ia64, glibc 2.2.2, 2.1.2 and 2.1.3.
> I've tried gcc and sgicc (Pro64).  Am I doing something so trivially
> wrong that I don't see it?  
> 
> 
> Script started on Mon Mar 19 16:55:03 2001
> address@hidden /extra/code% ldd --version
> ldd (GNU libc) 2.2.2
> Copyright (C) 1999 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> Written by Roland McGrath and Ulrich Drepper.
> address@hidden /extra/code% gcc --version
> 2.95.3
> address@hidden /extra/code% uname -a
> Linux maine 2.4.2 #1 Thu Feb 22 10:48:52 CST 2001 i686 unknown
> address@hidden /extra/code% cat fpathconf.c 
> #include <unistd.h>
> #include <errno.h>
> #include <string.h>
> #include <stdio.h>
> 
> int main()
> {
>       long ret;
> 
>       ret = fpathconf(-1, _PC_LINK_MAX);
>       printf("%hhd, errno: %d %s\n", ret, errno, strerror(errno));
> 
>       return ret;
> }
> address@hidden /extra/code% make fpathconf
> cc     fpathconf.c   -o fpathconf
> address@hidden /extra/code% ./fpathconf
> 127, errno: 9 Bad file descriptor
> address@hidden /extra/code% exit
> 
> Script done on Mon Mar 19 16:55:40 2001

Here's a patch to fix this.  Or should the check instead be:
      if (__fstatfs (fd, &fsbuf) < 0)
        {
          if (errno == ENOSYS)
            /* not possible, return the default value.  */
            return LINUX_LINK_MAX;
          /* Some error occured.  */
          return -1;
        }

Andreas

2001-03-20  Andreas Jaeger  <address@hidden>

        * sysdeps/unix/sysv/linux/fpathconf.c (__fpathconf): Check for bad
        file descriptor.


Index: fpathconf.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/unix/sysv/linux/fpathconf.c,v
retrieving revision 1.3
diff -u -c -r1.3 fpathconf.c
*** fpathconf.c 2000/06/08 10:04:50     1.3
--- fpathconf.c 2001/03/20 07:55:19
***************
*** 1,5 ****
  /* Linux specific extensions to fpathconf.
!    Copyright (C) 1991, 95, 96, 98, 99, 2000 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
--- 1,5 ----
  /* Linux specific extensions to fpathconf.
!    Copyright (C) 1991, 95, 96, 98, 99, 2000, 2001 Free Software Foundation, 
Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
***************
*** 17,22 ****
--- 17,23 ----
     write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.  */
  
+ #include <errno.h>
  #include <unistd.h>
  #include <limits.h>
  #include <sys/statfs.h>
***************
*** 42,50 ****
  
        /* Determine the filesystem type.  */
        if (__fstatfs (fd, &fsbuf) < 0)
!       /* not possible, return the default value.  */
!       return LINUX_LINK_MAX;
! 
        switch (fsbuf.f_type)
        {
        case EXT2_SUPER_MAGIC:
--- 43,56 ----
  
        /* Determine the filesystem type.  */
        if (__fstatfs (fd, &fsbuf) < 0)
!       {
!         if (errno == EBADF)
!           return -1;
!         
!         /* not possible, return the default value.  */
!         return LINUX_LINK_MAX;
!       }
!       
        switch (fsbuf.f_type)
        {
        case EXT2_SUPER_MAGIC:

-- 
 Andreas Jaeger
  SuSE Labs address@hidden
   private address@hidden
    http://www.suse.de/~aj