src/afs/HPUX/osi_gcpags.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 #include <afsconfig.h>
  11 #include "afs/param.h"
  12
  13
  14 #include "afs/sysincludes.h"    /* Standard vendor system headers */
  15 #include "afsincludes.h"        /* Afs-based standard headers */
  16 #include "afs/afs_stats.h"      /* afs statistics */
  17
  18 #if AFS_GCPAGS
  19
  20 /* afs_osi_TraverseProcTable() - Walk through the systems process
  21  * table, calling afs_GCPAGs_perproc_func() for each process.
  22  */
  23
  24
  25 /*
  26  * NOTE: h/proc_private.h gives the process table locking rules
  27  * It indicates that access to p_cred must be protected by
  28  * mp_mtproc_lock(p);
  29  * mp_mtproc_unlock(p);
  30  *
  31  * The code in sys/pm_prot.c uses pcred_lock() to protect access to
  32  * the process creds, and uses mp_mtproc_lock() only for audit-related
  33  * changes.  To be safe, we use both.
  34  */
  35
  36 void
  37 afs_osi_TraverseProcTable(void)
  38 {
  39     proc_t *p;
  40     int endchain = 0;
  41
  42     MP_SPINLOCK(activeproc_lock);
  43     MP_SPINLOCK(sched_lock);
  44     pcred_lock();
  45
  46     /*
  47      * Instead of iterating through all of proc[], traverse only
  48      * the list of active processes.  As an example of this,
  49      * see foreach_process() in sys/vm_sched.c.
  50      *
  51      * We hold the locks for the entire scan in order to get a
  52      * consistent view of the current set of creds.
  53      */
  54
  55     for (p = proc; endchain == 0; p = &proc[p->p_fandx]) {
  56         if (p->p_fandx == 0) {
  57             endchain = 1;
  58         }
  59
  60         if (system_proc(p))
  61             continue;
  62
  63         mp_mtproc_lock(p);
  64         afs_GCPAGs_perproc_func(p);
  65         mp_mtproc_unlock(p);
  66     }
  67
  68     pcred_unlock();
  69     MP_SPINUNLOCK(sched_lock);
  70     MP_SPINUNLOCK(activeproc_lock);
  71 }
  72
  73 /* return a pointer (sometimes a static copy ) to the cred for a
  74  * given afs_proc_t.
  75  * subsequent calls may overwrite the previously returned value.
  76  */
  77 const afs_ucred_t *
  78 afs_osi_proc2cred(afs_proc_t * p)
  79 {
  80     if (!p)
  81         return;
  82
  83     /*
  84      * Cannot use afs_warnuser() here, as the code path
  85      * eventually wants to grab sched_lock, which is
  86      * already held here
  87      */
  88
  89     return p_cred(p);
  90 }
  91
  92 #endif /* AFS_GCPAGS */