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 <afsconfig.h>
  15 #include "afs/param.h"
  16
  17 RCSID
  18     ("$Header$");
  19
  20 #include "afs/sysincludes.h"
  21 #include "afsincludes.h"
  22
  23 /* Setup a pool for creds. Allocate several at a time. */
  24 #define CRED_ALLOC_STEP 29      /* at 140 bytes/cred = 4060 bytes. */
  25
  26
  27 static cred_t *cred_pool = NULL;
  28 int cred_allocs = 0;
  29 int ncreds_inuse = 0;
  30
  31 /* Cred locking assumes current single threaded non-preemptive kernel.
  32  * Also assuming a fast path through both down and up if no waiters. Otherwise,
  33  * test if no creds in pool before grabbing lock in crfree().
  34  */
  35 #if defined(AFS_LINUX24_ENV)
  36 static DECLARE_MUTEX(linux_cred_pool_lock);
  37 #else
  38 static struct semaphore linux_cred_pool_lock = MUTEX;
  39 #endif
  40 #define CRED_LOCK() down(&linux_cred_pool_lock)
  41 #define CRED_UNLOCK() up(&linux_cred_pool_lock)
  42
  43 cred_t *
  44 crget(void)
  45 {
  46     cred_t *tmp;
  47     int i;
  48
  49     CRED_LOCK();
  50     if (!cred_pool) {
  51         cred_allocs++;
  52         cred_pool = (cred_t *) osi_Alloc(CRED_ALLOC_STEP * sizeof(cred_t));
  53         if (!cred_pool)
  54             osi_Panic("crget: No more memory for creds!\n");
  55
  56         for (i = 0; i < CRED_ALLOC_STEP - 1; i++)
  57             cred_pool[i].cr_ref = (long)&cred_pool[i + 1];
  58         cred_pool[i].cr_ref = 0;
  59     }
  60     tmp = cred_pool;
  61     cred_pool = (cred_t *) tmp->cr_ref;
  62     ncreds_inuse++;
  63     CRED_UNLOCK();
  64
  65     memset(tmp, 0, sizeof(cred_t));
  66 #if defined(AFS_LINUX26_ENV)
  67     tmp->cr_group_info = groups_alloc(0);
  68 #endif
  69     tmp->cr_ref = 1;
  70     return tmp;
  71 }
  72
  73 void
  74 crfree(cred_t * cr)
  75 {
  76     if (cr->cr_ref > 1) {
  77 #if defined(AFS_LINUX26_ENV)
  78         put_group_info(cr->cr_group_info);
  79 #endif
  80         cr->cr_ref--;
  81         return;
  82     }
  83
  84     CRED_LOCK();
  85     cr->cr_ref = (long)cred_pool;
  86     cred_pool = cr;
  87     CRED_UNLOCK();
  88     ncreds_inuse--;
  89 }
  90
  91
  92 /* Return a duplicate of the cred. */
  93 cred_t *
  94 crdup(cred_t * cr)
  95 {
  96     cred_t *tmp = crget();
  97
  98     tmp->cr_uid = cr->cr_uid;
  99     tmp->cr_ruid = cr->cr_ruid;
 100     tmp->cr_gid = cr->cr_gid;
 101 #if defined(AFS_LINUX26_ENV)
 102 {
 103     struct group_info *old_info;
 104
 105     old_info = tmp->cr_group_info;
 106     get_group_info(cr->cr_group_info);
 107     tmp->cr_group_info = cr->cr_group_info;
 108     put_group_info(old_info);
 109 }
 110 #else
 111     memcpy(tmp->cr_groups, cr->cr_groups, NGROUPS * sizeof(gid_t));
 112     tmp->cr_ngroups = cr->cr_ngroups;
 113 #endif
 114
 115     tmp->cr_ref = 1;
 116     return tmp;
 117 }
 118
 119 cred_t *
 120 crref(void)
 121 {
 122     cred_t *cr = crget();
 123
 124     cr->cr_uid = current->fsuid;
 125     cr->cr_ruid = current->uid;
 126     cr->cr_gid = current->fsgid;
 127     cr->cr_rgid = current->gid;
 128 #if defined(AFS_LINUX26_ENV)
 129 {
 130     struct group_info *old_info;
 131
 132     old_info = cr->cr_group_info;
 133     get_group_info(current->group_info);
 134     cr->cr_group_info = current->group_info;
 135     put_group_info(old_info);
 136 }
 137 #else
 138     memcpy(cr->cr_groups, current->groups, NGROUPS * sizeof(gid_t));
 139     cr->cr_ngroups = current->ngroups;
 140 #endif
 141     return cr;
 142 }
 143
 144
 145 /* Set the cred info into the current task */
 146 void
 147 crset(cred_t * cr)
 148 {
 149     current->fsuid = cr->cr_uid;
 150     current->uid = cr->cr_ruid;
 151     current->fsgid = cr->cr_gid;
 152     current->gid = cr->cr_rgid;
 153 #if defined(AFS_LINUX26_ENV)
 154 {
 155     struct group_info *old_info;
 156
 157     /* using set_current_groups() will sort the groups */
 158     old_info = current->group_info;
 159     get_group_info(cr->cr_group_info);
 160     current->group_info = cr->cr_group_info;
 161     put_group_info(old_info);
 162 }
 163 #else
 164     memcpy(current->groups, cr->cr_groups, NGROUPS * sizeof(gid_t));
 165     current->ngroups = cr->cr_ngroups;
 166 #endif
 167 }