PM75484: STANDARD OUTPUT OF OPERATIONS WHEN SET TO A DYNAMIC VIEW CAN NOT BE DETERMINED FROM THE /PROC FILESYSTEM ON SOLARIS

APAR status

• Closed as Permanent restriction.

Error description

• The /proc filesystem on Oracle Solaris presents information
  about running processes including output streams such as
  standard out (stdout) through /proc/pid/path/1 where 'pid' is
  the process identifier of a given process running on the system.
  When a user is set to a dynamic view in IBM Rational ClearCase
  and is accessing a VOB through the MultiVersion File System
  (MVFS), the standard output path is not displayed under
  /proc/pid/path.
  
  Steps to reproduce:
  
  1. Set to a view context and cd into a VOB.
  2. Run 'echo $$' to return the process id of the current shell.
  3. Run 'cat ? test' to begin writing to a test file.
  4. In another shell, run 'ptree ?pid?' where ?pid? is the
  process id from step 2.
  5. Locate the pid of the running 'cat' command below the shell.
  6. Run 'pfiles ?pid?' or 'ls -l /proc/?pid?/path' with the
  process id for cat command and note that the path for file
  descriptor 1 (standard out) is not present.
  
  Example:
  
  user1@host ? cleartool setview user11
  user1@host ? cd /vobs/vob1
  user1@host ? echo $$
  3087
  user1@host ? cat ? test
  ?let command run?
  
  root@host ? ptree 3087
  583   /usr/lib/ssh/sshd
    3023  /usr/lib/ssh/sshd
      3024  /usr/lib/ssh/sshd
        3030  -sh
          3034  bash -
            3086  sh
              3087  bash
                3090  cat
  
  root@host ? pfiles 3090
  3090:   cat
    Current rlimit: 256 file descriptors
     0: S_IFCHR mode:0620 dev:369,0 ino:12582920 uid:0 gid:7
  rdev:24,2
        O_RDWR|O_NOCTTY|O_LARGEFILE
        /devices/pseudo/pts@0:2
     1: S_IFREG mode:0644 dev:385,300 ino:2147483651 uid:42735
  gid:20 size:0
        O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE
     2: S_IFCHR mode:0620 dev:369,0 ino:12582920 uid:0 gid:7
  rdev:24,2
        O_RDWR|O_NOCTTY|O_LARGEFILE
        /devices/pseudo/pts@0:2
  
  root@host ? ls -l /proc/3090/path
  total 0
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20 0 -?
  /devices/pseudo/pts@0:2
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20 1
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20 2 -?
  /devices/pseudo/pts@0:2
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20 a.out -?
  /usr/bin/cat
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20 cwd -?
  /vobs/vob1
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20 root -?
  /view/user11
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20
  ufs.136.8.3106 -?
  /platform/sun4u-us3/lib/libc_psr/libc_psr_hwcap1.so.1
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20
  ufs.136.8.5483 -? /lib/ld.so.1
  lrwxrwxrwx   1 user1   user           0 Oct 19 16:20
  ufs.136.8.5488 -? /lib/libc.so.1
  
  
  Workaround: This behavior has not been seen outside of a setview
  context. Access a VOB using view-extended path without being set
  to a view. Linux hosts are unaffected and can access the desired
  path at /proc/pid/fd/1.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of ClearCase dynamic views on Oracle Solaris           *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * The /proc filesystem on Oracle Solaris presents information  *
  * about running processes including output streams such as     *
  * standard out (stdout) through /proc/pid/path/1 where "pid"   *
  * is the process identifier of a given process running on the  *
  * system. When a user is set to a dynamic view in IBM Rational *
  * ClearCase and is accessing a Versioned Object Base (VOB)     *
  * through the MultiVerson File System  (MVFS), the standard    *
  * output path is not displayed under /proc/pid/path.           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  There is a work-around available which is to ensure the process
  examining /proc for information about a ClearCase process that
  is in a view context has the same view context set.
  
  Specifically this means
  (1) obtain the view of the process you want to examine via the
  process PID by looking at the symbolic link pointed to by
  /proc/<PID>/path/root,
  (2) setting to this view context, and
  (3) then performing the examination of other path associated
  with the process via the /proc filesystem.
  

Problem conclusion

• We have no plan to fix this issue directly as it would involve
  changing the way lookup worked within the Solaris kernel code
  and would require a change by Oracle.
  The stdout path under /proc/<PID>/path/1 is a link, and the
  Solaris kernel code that is parsing that link obtains the
  filesystem root information for the current process instead of
  the target process.  This root pointer is used as the starting
  point for all pathnames, and so when dealing with a ClearCase
  setview, this is set to the vnode of the view the user is set
  to.  If the lookup isn't done with the proper starting vnode, it
  will be impossible for the lookup to succeed.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels