nscd/nscd.h

   1 /* Copyright (c) 1998-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _NSCD_H
  20 #define _NSCD_H 1
  21
  22 #include <pthread.h>
  23 #include <stdbool.h>
  24 #include <time.h>
  25 #include <sys/uio.h>
  26
  27 /* The declarations for the request and response types are in the file
  28    "nscd-client.h", which should contain everything needed by client
  29    functions.  */
  30 #include "nscd-client.h"
  31
  32
  33 /* Handle databases.  */
  34 typedef enum
  35 {
  36   pwddb,
  37   grpdb,
  38   hstdb,
  39   servdb,
  40   netgrdb,
  41   lastdb
  42 } dbtype;
  43
  44
  45 /* Default limit on the number of times a value gets reloaded without
  46    being used in the meantime.  NSCD does not throw a value out as
  47    soon as it times out.  It tries to reload the value from the
  48    server.  Only if the value has not been used for so many rounds it
  49    is removed.  */
  50 #define DEFAULT_RELOAD_LIMIT 5
  51
  52
  53 /* Time before restarting the process in paranoia mode.  */
  54 #define RESTART_INTERVAL (60 * 60)
  55
  56
  57 /* Stack size for worker threads.  */
  58 #define NSCD_THREAD_STACKSIZE 1024 * 1024 * (sizeof (void *) / 4)
  59
  60 /* Maximum size of stack frames we allow the thread to use.  We use
  61    80% of the thread stack size.  */
  62 #define MAX_STACK_USE ((8 * NSCD_THREAD_STACKSIZE) / 10)
  63
  64 /* Records the file registered per database that when changed
  65    or modified requires invalidating the database.  */
  66 struct traced_file
  67 {
  68   /* Tracks the last modified time of the traced file.  */
  69   time_t mtime;
  70   /* Support multiple registered files per database.  */
  71   struct traced_file *next;
  72   int call_res_init;
  73   /* Requires Inotify support to do anything useful.  */
  74 #define TRACED_FILE     0
  75 #define TRACED_DIR      1
  76   int inotify_descr[2];
  77 # ifndef PATH_MAX
  78 #  define PATH_MAX 1024
  79 # endif
  80   /* The parent directory is used to scan for creation/deletion.  */
  81   char dname[PATH_MAX];
  82   /* Just the name of the file with no directory component.  */
  83   char *sfname;
  84   /* The full-path name of the registered file.  */
  85   char fname[];
  86 };
  87
  88 /* Initialize a `struct traced_file`.  As input we need the name
  89    of the file, and if invalidation requires calling res_init.
  90    If CRINIT is 1 then res_init will be called after invalidation
  91    or if the traced file is changed in any way, otherwise it will
  92    not.  */
  93 static inline void
  94 init_traced_file(struct traced_file *file, const char *fname, int crinit)
  95 {
  96    char *dname;
  97    file->mtime = 0;
  98    file->inotify_descr[TRACED_FILE] = -1;
  99    file->inotify_descr[TRACED_DIR] = -1;
 100    strcpy (file->fname, fname);
 101    /* Compute the parent directory name and store a copy.  The copy makes
 102       it much faster to add/remove watches while nscd is running instead
 103       of computing this over and over again in a temp buffer.  */
 104    file->dname[0] = '\0';
 105    dname = strrchr (fname, '/');
 106    if (dname != NULL)
 107      {
 108        size_t len = (size_t)(dname - fname);
 109        if (len > sizeof (file->dname))
 110          abort ();
 111        memcpy (file->dname, file->fname, len);
 112        file->dname[len] = '\0';
 113      }
 114    /* The basename is the name just after the last forward slash.  */
 115    file->sfname = &dname[1];
 116    file->call_res_init = crinit;
 117 }
 118
 119 #define define_traced_file(id, filename)                        \
 120 static union                                                    \
 121 {                                                               \
 122   struct traced_file file;                                      \
 123   char buf[sizeof (struct traced_file) + sizeof (filename)];    \
 124 } id##_traced_file;
 125
 126 /* Structure describing dynamic part of one database.  */
 127 struct database_dyn
 128 {
 129   pthread_rwlock_t lock;
 130   pthread_cond_t prune_cond;
 131   pthread_mutex_t prune_lock;
 132   pthread_mutex_t prune_run_lock;
 133   time_t wakeup_time;
 134
 135   int enabled;
 136   int check_file;
 137   int clear_cache;
 138   int persistent;
 139   int shared;
 140   int propagate;
 141   struct traced_file *traced_files;
 142   const char *db_filename;
 143   size_t suggested_module;
 144   size_t max_db_size;
 145
 146   unsigned long int postimeout; /* In seconds.  */
 147   unsigned long int negtimeout; /* In seconds.  */
 148
 149   int wr_fd;                    /* Writable file descriptor.  */
 150   int ro_fd;                    /* Unwritable file descriptor.  */
 151
 152   const struct iovec *disabled_iov;
 153
 154   struct database_pers_head *head;
 155   char *data;
 156   size_t memsize;
 157   pthread_mutex_t memlock;
 158   bool mmap_used;
 159   bool last_alloc_failed;
 160 };
 161
 162
 163 /* Paths of the file for the persistent storage.  */
 164 #define _PATH_NSCD_PASSWD_DB    "/var/db/nscd/passwd"
 165 #define _PATH_NSCD_GROUP_DB     "/var/db/nscd/group"
 166 #define _PATH_NSCD_HOSTS_DB     "/var/db/nscd/hosts"
 167 #define _PATH_NSCD_SERVICES_DB  "/var/db/nscd/services"
 168 #define _PATH_NSCD_NETGROUP_DB  "/var/db/nscd/netgroup"
 169
 170 /* Path used when not using persistent storage.  */
 171 #define _PATH_NSCD_XYZ_DB_TMP   "/var/run/nscd/dbXXXXXX"
 172
 173 /* Maximum alignment requirement we will encounter.  */
 174 #define BLOCK_ALIGN_LOG 3
 175 #define BLOCK_ALIGN (1 << BLOCK_ALIGN_LOG)
 176 #define BLOCK_ALIGN_M1 (BLOCK_ALIGN - 1)
 177
 178 /* Default value for the maximum size of the database files.  */
 179 #define DEFAULT_MAX_DB_SIZE     (32 * 1024 * 1024)
 180
 181 /* Number of bytes of data we initially reserve for each hash table bucket.  */
 182 #define DEFAULT_DATASIZE_PER_BUCKET 1024
 183
 184 /* Default module of hash table.  */
 185 #define DEFAULT_SUGGESTED_MODULE 211
 186
 187
 188 /* Number of seconds between two cache pruning runs if we do not have
 189    better information when it is really needed.  */
 190 #define CACHE_PRUNE_INTERVAL    15
 191
 192
 193 /* Global variables.  */
 194 extern struct database_dyn dbs[lastdb] attribute_hidden;
 195 extern const char *const dbnames[lastdb];
 196 extern const char *const serv2str[LASTREQ];
 197
 198 extern const struct iovec pwd_iov_disabled;
 199 extern const struct iovec grp_iov_disabled;
 200 extern const struct iovec hst_iov_disabled;
 201 extern const struct iovec serv_iov_disabled;
 202 extern const struct iovec netgroup_iov_disabled;
 203
 204
 205 /* Initial number of threads to run.  */
 206 extern int nthreads;
 207 /* Maximum number of threads to use.  */
 208 extern int max_nthreads;
 209
 210 /* Inotify descriptor.  */
 211 extern int inotify_fd;
 212
 213 /* User name to run server processes as.  */
 214 extern const char *server_user;
 215
 216 /* Name and UID of user who is allowed to request statistics.  */
 217 extern const char *stat_user;
 218 extern uid_t stat_uid;
 219
 220 /* Time the server was started.  */
 221 extern time_t start_time;
 222
 223 /* Number of times clients had to wait.  */
 224 extern unsigned long int client_queued;
 225
 226 /* Maximum needed alignment.  */
 227 extern const size_t block_align;
 228
 229 /* Number of times a value is reloaded without being used.  UINT_MAX
 230    means unlimited.  */
 231 extern unsigned int reload_count;
 232
 233 /* Pagesize minus one.  */
 234 extern uintptr_t pagesize_m1;
 235
 236 /* Nonzero if paranoia mode is enabled.  */
 237 extern int paranoia;
 238 /* Time after which the process restarts.  */
 239 extern time_t restart_time;
 240 /* How much time between restarts.  */
 241 extern time_t restart_interval;
 242 /* Old current working directory.  */
 243 extern const char *oldcwd;
 244 /* Old user and group ID.  */
 245 extern uid_t old_uid;
 246 extern gid_t old_gid;
 247
 248
 249 /* Prototypes for global functions.  */
 250
 251 /* Wrapper functions with error checking for standard functions.  */
 252 #include <programs/xmalloc.h>
 253
 254 /* nscd.c */
 255 extern void termination_handler (int signum) __attribute__ ((__noreturn__));
 256 extern int nscd_open_socket (void);
 257 void notify_parent (int child_ret);
 258 void do_exit (int child_ret, int errnum, const char *format, ...);
 259
 260 /* connections.c */
 261 extern void nscd_init (void);
 262 extern void register_traced_file (size_t dbidx, struct traced_file *finfo);
 263 #ifdef HAVE_INOTIFY
 264 extern void install_watches (struct traced_file *finfo);
 265 #endif
 266 extern void close_sockets (void);
 267 extern void start_threads (void) __attribute__ ((__noreturn__));
 268
 269 /* nscd_conf.c */
 270 extern int nscd_parse_file (const char *fname,
 271                             struct database_dyn dbs[lastdb]);
 272
 273 /* nscd_stat.c */
 274 extern void send_stats (int fd, struct database_dyn dbs[lastdb]);
 275 extern int receive_print_stats (void) __attribute__ ((__noreturn__));
 276
 277 /* cache.c */
 278 extern struct datahead *cache_search (request_type, const void *key,
 279                                       size_t len, struct database_dyn *table,
 280                                       uid_t owner);
 281 extern int cache_add (int type, const void *key, size_t len,
 282                       struct datahead *packet, bool first,
 283                       struct database_dyn *table, uid_t owner,
 284                       bool prune_wakeup);
 285 extern time_t prune_cache (struct database_dyn *table, time_t now, int fd);
 286
 287 /* pwdcache.c */
 288 extern void addpwbyname (struct database_dyn *db, int fd, request_header *req,
 289                          void *key, uid_t uid);
 290 extern void addpwbyuid (struct database_dyn *db, int fd, request_header *req,
 291                         void *key, uid_t uid);
 292 extern time_t readdpwbyname (struct database_dyn *db, struct hashentry *he,
 293                              struct datahead *dh);
 294 extern time_t readdpwbyuid (struct database_dyn *db, struct hashentry *he,
 295                             struct datahead *dh);
 296
 297 /* grpcache.c */
 298 extern void addgrbyname (struct database_dyn *db, int fd, request_header *req,
 299                          void *key, uid_t uid);
 300 extern void addgrbygid (struct database_dyn *db, int fd, request_header *req,
 301                         void *key, uid_t uid);
 302 extern time_t readdgrbyname (struct database_dyn *db, struct hashentry *he,
 303                              struct datahead *dh);
 304 extern time_t readdgrbygid (struct database_dyn *db, struct hashentry *he,
 305                             struct datahead *dh);
 306
 307 /* hstcache.c */
 308 extern void addhstbyname (struct database_dyn *db, int fd, request_header *req,
 309                           void *key, uid_t uid);
 310 extern void addhstbyaddr (struct database_dyn *db, int fd, request_header *req,
 311                           void *key, uid_t uid);
 312 extern void addhstbynamev6 (struct database_dyn *db, int fd,
 313                             request_header *req, void *key, uid_t uid);
 314 extern void addhstbyaddrv6 (struct database_dyn *db, int fd,
 315                             request_header *req, void *key, uid_t uid);
 316 extern time_t readdhstbyname (struct database_dyn *db, struct hashentry *he,
 317                               struct datahead *dh);
 318 extern time_t readdhstbyaddr (struct database_dyn *db, struct hashentry *he,
 319                               struct datahead *dh);
 320 extern time_t readdhstbynamev6 (struct database_dyn *db, struct hashentry *he,
 321                                 struct datahead *dh);
 322 extern time_t readdhstbyaddrv6 (struct database_dyn *db, struct hashentry *he,
 323                                 struct datahead *dh);
 324
 325 /* aicache.c */
 326 extern void addhstai (struct database_dyn *db, int fd, request_header *req,
 327                       void *key, uid_t uid);
 328 extern time_t readdhstai (struct database_dyn *db, struct hashentry *he,
 329                           struct datahead *dh);
 330
 331
 332 /* initgrcache.c */
 333 extern void addinitgroups (struct database_dyn *db, int fd,
 334                            request_header *req, void *key, uid_t uid);
 335 extern time_t readdinitgroups (struct database_dyn *db, struct hashentry *he,
 336                                struct datahead *dh);
 337
 338 /* servicecache.c */
 339 extern void addservbyname (struct database_dyn *db, int fd,
 340                            request_header *req, void *key, uid_t uid);
 341 extern time_t readdservbyname (struct database_dyn *db, struct hashentry *he,
 342                                struct datahead *dh);
 343 extern void addservbyport (struct database_dyn *db, int fd,
 344                            request_header *req, void *key, uid_t uid);
 345 extern time_t readdservbyport (struct database_dyn *db, struct hashentry *he,
 346                                struct datahead *dh);
 347
 348 /* netgroupcache.c */
 349 extern void addinnetgr (struct database_dyn *db, int fd, request_header *req,
 350                         void *key, uid_t uid);
 351 extern time_t readdinnetgr (struct database_dyn *db, struct hashentry *he,
 352                             struct datahead *dh);
 353 extern void addgetnetgrent (struct database_dyn *db, int fd,
 354                             request_header *req, void *key, uid_t uid);
 355 extern time_t readdgetnetgrent (struct database_dyn *db, struct hashentry *he,
 356                                 struct datahead *dh);
 357
 358 /* mem.c */
 359 extern void *mempool_alloc (struct database_dyn *db, size_t len,
 360                             int data_alloc);
 361 extern void gc (struct database_dyn *db);
 362
 363
 364 /* nscd_setup_thread.c */
 365 extern int setup_thread (struct database_dyn *db);
 366
 367 /* cachedumper.c */
 368 extern void nscd_print_cache (const char *name);
 369
 370 /* Special version of TEMP_FAILURE_RETRY for functions returning error
 371    values.  */
 372 #define TEMP_FAILURE_RETRY_VAL(expression) \
 373   (__extension__                                                              \
 374     ({ long int __result;                                                     \
 375        do __result = (long int) (expression);                                 \
 376        while (__result == EINTR);                                             \
 377        __result; }))
 378
 379 #endif /* nscd.h */