src/afs/LINUX/osi_cred.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 /*
  11  * osi_cred.c - Linux cred handling routines.
  12  *
  13  */
  14 #include "../afs/param.h"
  15 #include <afsconfig.h>
  16
  17 RCSID("$Header$");
  18
  19 #include "../afs/sysincludes.h"
  20 #include "../afs/afsincludes.h"
  21
  22 /* Setup a pool for creds. Allocate several at a time. */
  23 #define CRED_ALLOC_STEP 29 /* at 140 bytes/cred = 4060 bytes. */
  24
  25
  26 static cred_t *cred_pool = NULL;
  27 int cred_allocs = 0;
  28 int ncreds_inuse = 0;
  29
  30 /* Cred locking assumes current single threaded non-preemptive kernel.
  31  * Also assuming a fast path through both down and up if no waiters. Otherwise,
  32  * test if no creds in pool before grabbing lock in crfree().
  33  */
  34 #if defined(AFS_LINUX24_ENV)
  35 static DECLARE_MUTEX(linux_cred_pool_lock);
  36 #else
  37 static struct semaphore linux_cred_pool_lock = MUTEX;
  38 #endif
  39 #define CRED_LOCK() down(&linux_cred_pool_lock)
  40 #define CRED_UNLOCK() up(&linux_cred_pool_lock)
  41
  42 cred_t *crget(void)
  43 {
  44     cred_t *tmp;
  45     int i;
  46
  47     CRED_LOCK();
  48     if (!cred_pool) {
  49         cred_allocs++;
  50         cred_pool = (cred_t*)osi_Alloc(CRED_ALLOC_STEP * sizeof(cred_t));
  51         if (!cred_pool)
  52             osi_Panic("crget: No more memory for creds!\n");
  53
  54         for (i=0; i < CRED_ALLOC_STEP-1; i++)
  55             cred_pool[i].cr_ref = (long)&cred_pool[i+1];
  56         cred_pool[i].cr_ref = 0;
  57     }
  58     tmp = cred_pool;
  59     cred_pool = (cred_t*)tmp->cr_ref;
  60     ncreds_inuse++;
  61     CRED_UNLOCK();
  62
  63     memset(tmp, 0, sizeof(cred_t));
  64     tmp->cr_ref = 1;
  65     return tmp;
  66 }
  67
  68 void crfree(cred_t *cr)
  69 {
  70     if (cr->cr_ref > 1) {
  71         cr->cr_ref--;
  72         return;
  73     }
  74
  75     CRED_LOCK();
  76     cr->cr_ref = (long)cred_pool;
  77     cred_pool = cr;
  78     CRED_UNLOCK();
  79     ncreds_inuse --;
  80 }
  81
  82
  83 /* Return a duplicate of the cred. */
  84 cred_t *crdup(cred_t *cr)
  85 {
  86     cred_t *tmp = crget();
  87     *tmp = *cr;
  88     tmp->cr_ref = 1;
  89     return tmp;
  90 }
  91
  92 cred_t *crref(void)
  93 {
  94     cred_t *cr = crget();
  95     cr->cr_uid = current->fsuid;
  96     cr->cr_ruid = current->uid;
  97     cr->cr_gid = current->fsgid;
  98     cr->cr_rgid = current->gid;
  99     memcpy(cr->cr_groups, current->groups, NGROUPS * sizeof(gid_t));
 100     cr->cr_ngroups = current->ngroups;
 101     return cr;
 102 }
 103
 104
 105 /* Set the cred info into the current task */
 106 void crset(cred_t *cr)
 107 {
 108     current->fsuid = cr->cr_uid;
 109     current->uid = cr->cr_ruid;
 110     current->fsgid = cr->cr_gid;
 111     current->gid = cr->cr_rgid;
 112     memcpy(current->groups, cr->cr_groups, NGROUPS * sizeof(gid_t));
 113     current->ngroups = cr->cr_ngroups;
 114 }