summaryrefslogtreecommitdiff
path: root/nss/nss_db/db-alias.c
blob: c5be8ba9cda3d97a6e46969dc18bd2e09b228192 (plain)
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
/* Mail alias file parser in nss_db module.
   Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <aliases.h>
#include <alloca.h>
#include <ctype.h>
#include <dlfcn.h>
#include <errno.h>
#include <bits/libc-lock.h>
#include <paths.h>
#include <string.h>

#include "nsswitch.h"
#include "nss_db.h"

/* Locks the static variables in this file.  */
__libc_lock_define_initialized (static, lock)

/* Maintenance of the shared handle open on the database.  */

static NSS_DB *db;
static int keep_db;
static unsigned int entidx;	/* Index for `getaliasent_r'. */


/* Open database.  */
enum nss_status
_nss_db_setaliasent (int stayopen)
{
  enum nss_status status;

  __libc_lock_lock (lock);

  status = internal_setent (_PATH_VARDB "aliases.db", &db);

  /* Remember STAYOPEN flag.  */
  if (db != NULL)
    keep_db |= stayopen;

  /* Reset the sequential index.  */
  entidx = 0;

  __libc_lock_unlock (lock);

  return status;
}


/* Close it again.  */
enum nss_status
_nss_db_endaliasent (void)
{
  __libc_lock_lock (lock);

  internal_endent (&db);

  /* Reset STAYOPEN flag.  */
  keep_db = 0;

  __libc_lock_unlock (lock);

  return NSS_STATUS_SUCCESS;
}

/* We provide the parse function here.  The parser in libnss_files
   cannot be used.  The generation of the db file already resolved all
   :include: statements so we simply have to parse the list and store
   the result.  */
static enum nss_status
lookup (DBT *key, struct aliasent *result, char *buffer,
	size_t buflen, int *errnop)
{
  enum nss_status status;
  DBT value;

  /* Open the database.  */
  if (db == NULL)
    {
      status = internal_setent (_PATH_VARDB "aliases.db", &db);
      if (status != NSS_STATUS_SUCCESS)
	{
	  *errnop = errno;
	  return status;
	}
    }

  value.flags = 0;
  if (DL_CALL_FCT (db->get, (db->db, NULL, key, &value, 0)) == 0)
    {
      const char *src = value.data;
      char *cp;
      size_t cnt;

      result->alias_members_len = 0;

      /* We now have to fill the BUFFER with all the information. */
      if (buflen < key->size + 1)
	{
	no_more_room:
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      buffer = stpncpy (buffer, key->data, key->size) + 1;
      buflen -= key->size + 1;

      while (*src != '\0')
	{
	  const char *end, *upto;
	  while (isspace (*src))
	    ++src;

	  end = strchr (src, ',');
	  if (end == NULL)
	    end = strchr (src, '\0');
	  for (upto = end; upto > src && isspace (upto[-1]); --upto);

	  if (upto != src)
	    {
	      if ((upto - src) + __alignof__ (char *) > buflen)
		goto no_more_room;
	      buffer = stpncpy (buffer, src, upto - src) + 1;
	      buflen -= (upto - src) + __alignof (char *);
	      ++result->alias_members_len;
	    }
	  src = end + (*end != '\0');
	}

      /* Now prepare the return.  Provide string pointers for the
	 currently selected aliases.  */

      /* Adjust the pointer so it is aligned for storing pointers.  */
      buffer += __alignof__ (char *) - 1;
      buffer -= ((buffer - (char *) 0) % __alignof__ (char *));
      result->alias_members = (char **) buffer;

      /* Compute addresses of alias entry strings.  */
      cp = result->alias_name;
      for (cnt = 0; cnt < result->alias_members_len; ++cnt)
	{
	  cp = strchr (cp, '\0') + 1;
	  result->alias_members[cnt] = cp;
	}

      status = (result->alias_members_len == 0
		? NSS_STATUS_RETURN : NSS_STATUS_SUCCESS);
    }
  else
    status = NSS_STATUS_NOTFOUND;

  if (! keep_db)
    internal_endent (&db);

  return status;
}

enum nss_status
_nss_db_getaliasent_r (struct aliasent *result, char *buffer, size_t buflen,
		       int *errnop)
{
  /* Return next entry in alias file.  */
  enum nss_status status;
  char buf[20];
  DBT key;

  __libc_lock_lock (lock);
  key.size = snprintf (key.data = buf, sizeof buf, "0%u", entidx++);
  key.flags = 0;
  status = lookup (&key, result, buffer, buflen, errnop);
  if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
    /* Give the user a chance to get the same entry with a larger buffer.  */
    --entidx;
  __libc_lock_unlock (lock);

  return status;
}


enum nss_status
_nss_db_getaliasbyname_r (const char *name, struct aliasent *result,
			  char *buffer, size_t buflen, int *errnop)
{
  DBT key;
  enum nss_status status;

  key.size = 1 + strlen (name);

  key.data = __alloca (key.size);
  ((char *) key.data)[0] = '.';
  memcpy (&((char *) key.data)[1], name, key.size - 1);
  key.flags = 0;

  __libc_lock_lock (lock);
  status = lookup (&key, result, buffer, buflen, errnop);
  __libc_lock_unlock (lock);

  return status;
}