bin/73319: realpath() produces incorrect results when called from threaded programs

[James Van Bokkelen]

>Number:         73319
>Category:       bin
>Synopsis:       realpath() produces incorrect results when called from threaded programs
>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 Oct 30 17:50:22 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     James Van Bokkelen
>Release:        FreeBSD 5.3-RC1
>Organization:
Sandstorm Enterprises Inc.
>Environment:
FreeBSD j3.sandstorm.net 5.3RC1 FreeBSD 5.3-RC1 #0 Sun Oct 17 01:25:37 UTC 2004  root at wv1u.samsco.home:/usr/obj/src/sys/GENERIC i386
>Description:
      When invoked via the 'realpath' command or from a non-threaded application, realpath("/usr/ni", buf) returns "/usr/ni".  But when invoked from a threaded app, it returns "/us/ni".  Other paths using more than one '/' character fail in the same way.
>How-To-Repeat:
      A threaded Qt application we are porting from 4.8 failed because its QFileDialog objects could not navigate the file system.  Using gdb, we found that realpath() was returning incorrect results.  I then wrote a simple test program, which worked right, as does the 'realpath' command.  I then added a call to realpath() to a threaded C-language app (no Qt or C++ use at all), and it fails the same way.  If requested, I will put together a simple demonstration, but I thought I'd submit the inital report ASAP. 
>Fix:
      haven't begun to review the source yet.
>Release-Note:
>Audit-Trail:
>Unformatted: