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