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Date: Sat, 9 Mar 2002 12:28:07 +0100 (CET)
From: Slaven Rezic <eserte@vran.herceg.de>
Reply-To: Slaven Rezic <slaven.rezic@berlin.de>
To: FreeBSD-gnats-submit@freebsd.org
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Subject: kern/35703: /proc/curproc/file returns unknown
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>Number:         35703
>Category:       kern
>Synopsis:       /proc/curproc/file returns unknown
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Mar 09 03:40:04 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     Slaven Rezic
>Release:        FreeBSD 4.3-STABLE i386
>Organization:
www.rezic.de
>Environment:
System: FreeBSD vran.herceg.de 4.3-STABLE FreeBSD 4.3-STABLE #6: Mon Jul 9 11:49:47 CEST 2001 root@vran.herceg.de:/vran/home/src/FreeBSD-4/src/sys/compile/VRAN i386

>Description:
	Under some circumstances, the symbolic link
	/proc/<anything>/file points to "unknown". In my experiments
	it seems that this is the case if a directory is created
	and/or removed in the as the executable and the executable is
	called with a relative path. Some of the sysctl variables
	vfs.cache.numfullpathfail[1-4] are increased.

	This problem causes one test failure in perl5.7.3.

>How-To-Repeat:
	Compile the program below:
----------------------------------------------------------------------
#include <unistd.h>
main() {
  char buf[1024];
  int len = readlink("/proc/curproc/file", buf, 1024);
  if (!len) exit(1);
  buf[len]=0;
  printf("<%s>\n", buf);
}
----------------------------------------------------------------------
	If run as ./a.out, it works OK.
	However, if a subdirectory in the same directory is deleted,
	then the program returns "unknown":

		mkdir foo ; rmdir foo ; ./a.out

	This works again:

		mkdir foo ; rmdir foo ; `pwd`/a.out

>Fix:

	???
>Release-Note:
>Audit-Trail:
>Unformatted:

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