OS-4408 /native/usr/bin/ps should work in a lx branded zone
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 25,35 ****
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
  /*
!  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
   */
  
  /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*        All Rights Reserved   */
  
--- 25,35 ----
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
  /*
!  * Copyright 2015 Joyent, Inc.
   */
  
  /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*        All Rights Reserved   */
  
*** 284,294 ****
  static  int     nzoneid = 0;
  
  static  int     kbytes_per_page;
  static  int     pidwidth;
  
! static  char    *procdir = "/proc";     /* standard /proc directory */
  
  static struct ughead    euid_tbl;       /* table to store selected euid's */
  static struct ughead    ruid_tbl;       /* table to store selected real uid's */
  static struct ughead    egid_tbl;       /* table to store selected egid's */
  static struct ughead    rgid_tbl;       /* table to store selected real gid's */
--- 284,294 ----
  static  int     nzoneid = 0;
  
  static  int     kbytes_per_page;
  static  int     pidwidth;
  
! static  char    procdir[MAXPATHLEN];    /* standard /proc directory */
  
  static struct ughead    euid_tbl;       /* table to store selected euid's */
  static struct ughead    ruid_tbl;       /* table to store selected real uid's */
  static struct ughead    egid_tbl;       /* table to store selected egid's */
  static struct ughead    rgid_tbl;       /* table to store selected real gid's */
*** 337,348 ****
--- 337,356 ----
  
  int
  main(int argc, char **argv)
  {
          const char *me;
+         const char *zroot = zone_get_nroot();
  
          /*
+          * If this is a branded zone, the native procfs may mounted in a
+          * non-standard location.  Apply such a path prefix if it exists.
+          */
+         (void) snprintf(procdir, sizeof (procdir), "%s/proc", zroot != NULL ?
+             zroot : "");
+ 
+         /*
           * The original two ps'es are linked in a single binary;
           * their main()s are renamed to stdmain for /usr/bin/ps and
           * ucbmain for /usr/ucb/ps.
           * We try to figure out which instance of ps the user wants to run.
           * Traditionally, the UCB variant doesn't require the flag argument