about summary refs log tree commit diff
path: root/nscd/nscd-client.h
blob: ee16df60835eabe5ed2ab94b4890b9f3a9b02782 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
/* Copyright (c) 1998-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

/* This file defines everything that client code should need to
   know to talk to the nscd daemon.  */

#ifndef _NSCD_CLIENT_H
#define _NSCD_CLIENT_H	1

#include <stdbool.h>
#include <stdint.h>
#include <sys/types.h>
#include <atomic.h>
#include <nscd-types.h>
#include <sys/uio.h>


/* Version number of the daemon interface */
#define NSCD_VERSION 2

/* Path of the file where the PID of the running system is stored.  */
#define _PATH_NSCDPID	 "/var/run/nscd/nscd.pid"

/* Path for the Unix domain socket.  */
#define _PATH_NSCDSOCKET "/var/run/nscd/socket"

/* Path for the configuration file.  */
#define _PATH_NSCDCONF	 "/etc/nscd.conf"

/* Maximum allowed length for the key.  */
#define MAXKEYLEN 1024


/* Available services.  */
typedef enum
{
  GETPWBYNAME,
  GETPWBYUID,
  GETGRBYNAME,
  GETGRBYGID,
  GETHOSTBYNAME,
  GETHOSTBYNAMEv6,
  GETHOSTBYADDR,
  GETHOSTBYADDRv6,
  SHUTDOWN,		/* Shut the server down.  */
  GETSTAT,		/* Get the server statistic.  */
  INVALIDATE,           /* Invalidate one special cache.  */
  GETFDPW,
  GETFDGR,
  GETFDHST,
  GETAI,
  INITGROUPS,
  GETSERVBYNAME,
  GETSERVBYPORT,
  GETFDSERV,
  GETNETGRENT,
  INNETGR,
  GETFDNETGR,
  LASTREQ
} request_type;


/* Header common to all requests */
typedef struct
{
  int32_t version;	/* Version number of the daemon interface.  */
  request_type type;	/* Service requested.  */
  int32_t key_len;	/* Key length.  */
} request_header;


/* Structure sent in reply to password query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t pw_name_len;
  nscd_ssize_t pw_passwd_len;
  uid_t pw_uid;
  gid_t pw_gid;
  nscd_ssize_t pw_gecos_len;
  nscd_ssize_t pw_dir_len;
  nscd_ssize_t pw_shell_len;
} pw_response_header;


/* Structure sent in reply to group query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t gr_name_len;
  nscd_ssize_t gr_passwd_len;
  gid_t gr_gid;
  nscd_ssize_t gr_mem_cnt;
} gr_response_header;


/* Structure sent in reply to host query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t h_name_len;
  nscd_ssize_t h_aliases_cnt;
  int32_t h_addrtype;
  int32_t h_length;
  nscd_ssize_t h_addr_list_cnt;
  int32_t error;
} hst_response_header;


/* Structure sent in reply to addrinfo query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t naddrs;
  nscd_ssize_t addrslen;
  nscd_ssize_t canonlen;
  int32_t error;
} ai_response_header;

/* Structure filled in by __nscd_getai.  */
struct nscd_ai_result
{
  int naddrs;
  char *canon;
  uint8_t *family;
  char *addrs;
};

/* Structure sent in reply to initgroups query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t ngrps;
} initgr_response_header;


/* Structure sent in reply to services query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t s_name_len;
  nscd_ssize_t s_proto_len;
  nscd_ssize_t s_aliases_cnt;
  int32_t s_port;
} serv_response_header;


/* Structure send in reply to netgroup query.  Note that this struct is
   sent also if the service is disabled or there is no record found.  */
typedef struct
{
  int32_t version;
  int32_t found;
  nscd_ssize_t nresults;
  nscd_ssize_t result_len;
} netgroup_response_header;

typedef struct
{
  int32_t version;
  int32_t found;
  int32_t result;
} innetgroup_response_header;


/* Type for offsets in data part of database.  */
typedef uint32_t ref_t;
/* Value for invalid/no reference.  */
#define ENDREF	UINT32_MAX

/* Timestamp type.  */
typedef uint64_t nscd_time_t;

/* Maximum timestamp.  */
#define MAX_TIMEOUT_VALUE \
  (sizeof (time_t) == sizeof (long int) ? LONG_MAX : INT_MAX)

/* Alignment requirement of the beginning of the data region.  */
#define ALIGN 16


/* Head of record in data part of database.  */
struct datahead
{
  nscd_ssize_t allocsize;	/* Allocated Bytes.  */
  nscd_ssize_t recsize;		/* Size of the record.  */
  nscd_time_t timeout;		/* Time when this entry becomes invalid.  */
  uint8_t notfound;		/* Nonzero if data has not been found.  */
  uint8_t nreloads;		/* Reloads without use.  */
  uint8_t usable;		/* False if the entry must be ignored.  */
  uint8_t unused;		/* Unused.  */
  uint32_t ttl;			/* TTL value used.  */

  /* We need to have the following element aligned for the response
     header data types and their use in the 'struct dataset' types
     defined in the XXXcache.c files.  */
  union
  {
    pw_response_header pwdata;
    gr_response_header grdata;
    hst_response_header hstdata;
    ai_response_header aidata;
    initgr_response_header initgrdata;
    serv_response_header servdata;
    netgroup_response_header netgroupdata;
    innetgroup_response_header innetgroupdata;
    nscd_ssize_t align1;
    nscd_time_t align2;
  } data[0];
};

static inline time_t
datahead_init_common (struct datahead *head, nscd_ssize_t allocsize,
		      nscd_ssize_t recsize, uint32_t ttl)
{
  /* Initialize so that we don't write out junk in uninitialized data to the
     cache.  */
  memset (head, 0, sizeof (*head));

  head->allocsize = allocsize;
  head->recsize = recsize;
  head->usable = true;

  head->ttl = ttl;

  /* Compute and return the timeout time.  */
  return head->timeout = time (NULL) + ttl;
}

static inline time_t
datahead_init_pos (struct datahead *head, nscd_ssize_t allocsize,
		   nscd_ssize_t recsize, uint8_t nreloads, uint32_t ttl)
{
  time_t ret = datahead_init_common (head, allocsize, recsize, ttl);

  head->notfound = false;
  head->nreloads = nreloads;

  return ret;
}

static inline time_t
datahead_init_neg (struct datahead *head, nscd_ssize_t allocsize,
		   nscd_ssize_t recsize, uint32_t ttl)
{
  time_t ret = datahead_init_common (head, allocsize, recsize, ttl);

  /* We don't need to touch nreloads here since it is set to our desired value
     (0) when we clear the structure.  */
  head->notfound = true;

  return ret;
}

/* Structure for one hash table entry.  */
struct hashentry
{
  request_type type:8;		/* Which type of dataset.  */
  bool first;			/* True if this was the original key.  */
  nscd_ssize_t len;		/* Length of key.  */
  ref_t key;			/* Pointer to key.  */
  int32_t owner;		/* If secure table, this is the owner.  */
  ref_t next;			/* Next entry in this hash bucket list.  */
  ref_t packet;			/* Records for the result.  */
  union
  {
    struct hashentry *dellist;	/* Next record to be deleted.  This can be a
				   pointer since only nscd uses this field.  */
    ref_t *prevp;		/* Pointer to field containing forward
				   reference.  */
  };
};


/* Current persistent database version.  */
#define DB_VERSION	2

/* Maximum time allowed between updates of the timestamp.  */
#define MAPPING_TIMEOUT (5 * 60)


/* Used indices for the EXTRA_DATA element of 'database_pers_head'.
   Each database has its own indices.  */
#define NSCD_HST_IDX_CONF_TIMESTAMP	0


/* Header of persistent database file.  */
struct database_pers_head
{
  int32_t version;
  int32_t header_size;
  volatile int32_t gc_cycle;
  volatile int32_t nscd_certainly_running;
  volatile nscd_time_t timestamp;
  /* Room for extensions.  */
  volatile uint32_t extra_data[4];

  nscd_ssize_t module;
  nscd_ssize_t data_size;

  nscd_ssize_t first_free;	/* Offset of first free byte in data area.  */

  nscd_ssize_t nentries;
  nscd_ssize_t maxnentries;
  nscd_ssize_t maxnsearched;

  uint64_t poshit;
  uint64_t neghit;
  uint64_t posmiss;
  uint64_t negmiss;

  uint64_t rdlockdelayed;
  uint64_t wrlockdelayed;

  uint64_t addfailed;

  ref_t array[0];
};


/* Mapped database record.  */
struct mapped_database
{
  const struct database_pers_head *head;
  const char *data;
  size_t mapsize;
  int counter;		/* > 0 indicates it is usable.  */
  size_t datasize;
};
#define NO_MAPPING ((struct mapped_database *) -1l)

struct locked_map_ptr
{
  int lock;
  struct mapped_database *mapped;
};
#define libc_locked_map_ptr(class, name) class struct locked_map_ptr name

/* Try acquiring lock for mapptr, returns true if it succeeds, false
   if not.  */
static inline bool
__nscd_acquire_maplock (volatile struct locked_map_ptr *mapptr)
{
  int cnt = 0;
  while (__builtin_expect (atomic_compare_and_exchange_val_acq (&mapptr->lock,
								1, 0) != 0, 0))
    {
      // XXX Best number of rounds?
      if (__glibc_unlikely (++cnt > 5))
	return false;

      atomic_delay ();
    }

  return true;
}


/* Open socket connection to nscd server.  */
extern int __nscd_open_socket (const char *key, size_t keylen,
			       request_type type, void *response,
			       size_t responselen) attribute_hidden;

/* Try to get a file descriptor for the shared meory segment
   containing the database.  */
extern struct mapped_database *__nscd_get_mapping (request_type type,
						   const char *key,
						   struct mapped_database **mappedp) attribute_hidden;

/* Get reference of mapping.  */
extern struct mapped_database *__nscd_get_map_ref (request_type type,
						   const char *name,
						   volatile struct locked_map_ptr *mapptr,
						   int *gc_cyclep);

/* Unmap database.  */
extern void __nscd_unmap (struct mapped_database *mapped);

/* Drop reference of mapping.  */
static int
__attribute__ ((unused))
__nscd_drop_map_ref (struct mapped_database *map, int *gc_cycle)
{
  if (map != NO_MAPPING)
    {
      int now_cycle = map->head->gc_cycle;
      if (__glibc_unlikely (now_cycle != *gc_cycle))
	{
	  /* We might have read inconsistent data.  */
	  *gc_cycle = now_cycle;
	  return -1;
	}

      if (atomic_decrement_val (&map->counter) == 0)
	__nscd_unmap (map);
    }

  return 0;
}


/* Search the mapped database.  */
extern struct datahead *__nscd_cache_search (request_type type,
					     const char *key,
					     size_t keylen,
					     const struct mapped_database *mapped,
					     size_t datalen);

/* Wrappers around read, readv and write that only read/write less than LEN
   bytes on error or EOF.  */
extern ssize_t __readall (int fd, void *buf, size_t len)
  attribute_hidden;
extern ssize_t __readvall (int fd, const struct iovec *iov, int iovcnt)
  attribute_hidden;
extern ssize_t writeall (int fd, const void *buf, size_t len)
  attribute_hidden;
extern ssize_t sendfileall (int tofd, int fromfd, off_t off, size_t len)
  attribute_hidden;

/* Get netlink timestamp counter from mapped area or zero.  */
extern uint32_t __nscd_get_nl_timestamp (void);

#endif /* nscd.h */