lib/blkid/cache.c

   1 /*
   2  * cache.c - allocation/initialization/free routines for cache
   3  *
   4  * Copyright (C) 2001 Andreas Dilger
   5  * Copyright (C) 2003 Theodore Ts'o
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the
   9  * GNU Lesser General Public License.
  10  * %End-Header%
  11  */
  12
  13 #if HAVE_UNISTD_H
  14 #include <unistd.h>
  15 #endif
  16 #ifdef HAVE_ERRNO_H
  17 #include <errno.h>
  18 #endif
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #ifdef HAVE_SYS_PRCTL_H
  22 #include <sys/prctl.h>
  23 #else
  24 #define PR_GET_DUMPABLE 3
  25 #endif
  26 #if (!defined(HAVE_PRCTL) && defined(linux))
  27 #include <sys/syscall.h>
  28 #endif
  29 #ifdef HAVE_SYS_STAT_H
  30 #include <sys/stat.h>
  31 #endif
  32 #include "blkidP.h"
  33
  34 int blkid_debug_mask = 0;
  35
  36
  37 static char *safe_getenv(const char *arg)
  38 {
  39         if ((getuid() != geteuid()) || (getgid() != getegid()))
  40                 return NULL;
  41 #if HAVE_PRCTL
  42         if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
  43                 return NULL;
  44 #else
  45 #if (defined(linux) && defined(SYS_prctl))
  46         if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
  47                 return NULL;
  48 #endif
  49 #endif
  50
  51 #ifdef HAVE___SECURE_GETENV
  52         return __secure_getenv(arg);
  53 #else
  54         return getenv(arg);
  55 #endif
  56 }
  57
  58 #if 0 /* ifdef CONFIG_BLKID_DEBUG */
  59 static blkid_debug_dump_cache(int mask, blkid_cache cache)
  60 {
  61         struct list_head *p;
  62
  63         if (!cache) {
  64                 printf("cache: NULL\n");
  65                 return;
  66         }
  67
  68         printf("cache: time = %lu\n", cache->bic_time);
  69         printf("cache: flags = 0x%08X\n", cache->bic_flags);
  70
  71         list_for_each(p, &cache->bic_devs) {
  72                 blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
  73                 blkid_debug_dump_dev(dev);
  74         }
  75 }
  76 #endif
  77
  78 int blkid_get_cache(blkid_cache *ret_cache, const char *filename)
  79 {
  80         blkid_cache cache;
  81
  82 #ifdef CONFIG_BLKID_DEBUG
  83         if (!(blkid_debug_mask & DEBUG_INIT)) {
  84                 char *dstr = getenv("BLKID_DEBUG");
  85
  86                 if (dstr)
  87                         blkid_debug_mask = strtoul(dstr, 0, 0);
  88                 blkid_debug_mask |= DEBUG_INIT;
  89         }
  90 #endif
  91
  92         DBG(DEBUG_CACHE, printf("creating blkid cache (using %s)\n",
  93                                 filename ? filename : "default cache"));
  94
  95         if (!(cache = (blkid_cache) calloc(1, sizeof(struct blkid_struct_cache))))
  96                 return -BLKID_ERR_MEM;
  97
  98         INIT_LIST_HEAD(&cache->bic_devs);
  99         INIT_LIST_HEAD(&cache->bic_tags);
 100
 101         if (filename && !strlen(filename))
 102                 filename = 0;
 103         if (!filename)
 104                 filename = safe_getenv("BLKID_FILE");
 105         if (!filename)
 106                 filename = BLKID_CACHE_FILE;
 107         cache->bic_filename = blkid_strdup(filename);
 108
 109         blkid_read_cache(cache);
 110
 111         *ret_cache = cache;
 112         return 0;
 113 }
 114
 115 void blkid_put_cache(blkid_cache cache)
 116 {
 117         if (!cache)
 118                 return;
 119
 120         (void) blkid_flush_cache(cache);
 121
 122         DBG(DEBUG_CACHE, printf("freeing cache struct\n"));
 123
 124         /* DBG(DEBUG_CACHE, blkid_debug_dump_cache(cache)); */
 125
 126         while (!list_empty(&cache->bic_devs)) {
 127                 blkid_dev dev = list_entry(cache->bic_devs.next,
 128                                            struct blkid_struct_dev,
 129                                             bid_devs);
 130                 blkid_free_dev(dev);
 131         }
 132
 133         while (!list_empty(&cache->bic_tags)) {
 134                 blkid_tag tag = list_entry(cache->bic_tags.next,
 135                                            struct blkid_struct_tag,
 136                                            bit_tags);
 137
 138                 while (!list_empty(&tag->bit_names)) {
 139                         blkid_tag bad = list_entry(tag->bit_names.next,
 140                                                    struct blkid_struct_tag,
 141                                                    bit_names);
 142
 143                         DBG(DEBUG_CACHE, printf("warning: unfreed tag %s=%s\n",
 144                                                 bad->bit_name, bad->bit_val));
 145                         blkid_free_tag(bad);
 146                 }
 147                 blkid_free_tag(tag);
 148         }
 149         free(cache->bic_filename);
 150
 151         free(cache);
 152 }
 153
 154 void blkid_gc_cache(blkid_cache cache)
 155 {
 156         struct list_head *p, *pnext;
 157         struct stat st;
 158
 159         if (!cache)
 160                 return;
 161
 162         list_for_each_safe(p, pnext, &cache->bic_devs) {
 163                 blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
 164                 if (!p)
 165                         break;
 166                 if (stat(dev->bid_name, &st) < 0) {
 167                         DBG(DEBUG_CACHE,
 168                             printf("freeing %s\n", dev->bid_name));
 169                         blkid_free_dev(dev);
 170                         cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 171                 } else {
 172                         DBG(DEBUG_CACHE,
 173                             printf("Device %s exists\n", dev->bid_name));
 174                 }
 175         }
 176 }
 177
 178
 179 #ifdef TEST_PROGRAM
 180 int main(int argc, char** argv)
 181 {
 182         blkid_cache cache = NULL;
 183         int ret;
 184
 185         blkid_debug_mask = DEBUG_ALL;
 186         if ((argc > 2)) {
 187                 fprintf(stderr, "Usage: %s [filename] \n", argv[0]);
 188                 exit(1);
 189         }
 190
 191         if ((ret = blkid_get_cache(&cache, argv[1])) < 0) {
 192                 fprintf(stderr, "error %d parsing cache file %s\n", ret,
 193                         argv[1] ? argv[1] : BLKID_CACHE_FILE);
 194                 exit(1);
 195         }
 196         if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
 197                 fprintf(stderr, "%s: error creating cache (%d)\n",
 198                         argv[0], ret);
 199                 exit(1);
 200         }
 201         if ((ret = blkid_probe_all(cache) < 0))
 202                 fprintf(stderr, "error probing devices\n");
 203
 204         blkid_put_cache(cache);
 205
 206         return ret;
 207 }
 208 #endif