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9a6450d5 UD |
1 | /* Common database open/close routines for nss_db. |
2 | Copyright (C) 1999, 2000 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | 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 | Library General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Library General Public | |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #include <fcntl.h> | |
21 | #include <dlfcn.h> | |
22 | #include <errno.h> | |
23 | #include <stdlib.h> | |
24 | #include <bits/libc-lock.h> | |
25 | ||
26 | #include "dummy-db.h" | |
27 | #include "nsswitch.h" | |
28 | #include "nss_db.h" | |
29 | ||
30 | /* This file contains the functions used to open and close the databases | |
31 | read by the rest of libnss_db. They are not thread safe; the caller | |
32 | must handle locking. | |
33 | ||
34 | We dynamically load the database library, so that it does not have | |
35 | to be present when glibc is compiled. Once loaded, libdb is never | |
36 | unloaded again unless this library is unloaded (from the free_mem | |
37 | routine in nsswitch.c) - we catch the unload by providing a shlib | |
38 | destructor. (XXX Does it work?) */ | |
39 | ||
40 | static void *libdb_handle; | |
41 | enum { | |
42 | nodb, | |
43 | db24, | |
44 | db27 | |
45 | } libdb_version; | |
46 | static int (*libdb_db_open) (const char *, int, | |
47 | uint32_t, int, void *, void *, void **); | |
48 | ||
49 | /* Locks the static variables in this file. */ | |
50 | __libc_lock_define_initialized (static, lock) | |
51 | ||
52 | /* Dynamically load the database library. | |
53 | We try libdb2.so.3, maybe others in the future. */ | |
54 | static int | |
55 | load_db (void) | |
56 | { | |
57 | static const char *libnames[] = { "libdb.so.3" }; | |
58 | int x; | |
59 | ||
793bd4d9 | 60 | for(x = 0; x < sizeof (libnames) / sizeof (libnames[0]); ++x) |
9a6450d5 UD |
61 | { |
62 | libdb_handle = dlopen (libnames[x], RTLD_LAZY); | |
63 | if (libdb_handle == NULL) | |
64 | continue; | |
65 | ||
66 | libdb_db_open = dlsym (libdb_handle, "db_open"); | |
793bd4d9 | 67 | if (libdb_db_open != NULL) |
9a6450d5 UD |
68 | { |
69 | /* Alright, we got a library. Now find out which version it is. */ | |
70 | const char *(*db_version) (int *, int *, int *); | |
71 | ||
72 | db_version = dlsym (libdb_handle, "db_version"); | |
73 | if (db_version != NULL) | |
74 | { | |
75 | /* Call the function and get the information. */ | |
76 | int major, minor, subminor; | |
77 | ||
78 | DL_CALL_FCT (db_version, (&major, &minor, &subminor)); | |
79 | if (major == 2) | |
80 | { | |
81 | /* We currently cannot handle other versions than the | |
82 | 2.x series. */ | |
83 | if (minor < 6 || (minor == 6 && subminor < 4)) | |
84 | libdb_version = db24; | |
85 | else | |
86 | libdb_version = db27; | |
87 | } | |
88 | } | |
89 | ||
90 | if (libdb_version != nodb) | |
91 | return 0; | |
92 | } | |
93 | ||
94 | dlclose (libdb_handle); | |
95 | } | |
96 | ||
97 | (void) dlerror (); | |
98 | return 1; | |
99 | } | |
100 | ||
101 | ||
102 | /* Make sure we don't use the library anymore once we are shutting down. */ | |
103 | static void __attribute__ ((destructor)) | |
104 | unload_db (void) | |
105 | { | |
106 | if (libdb_handle != NULL) | |
107 | { | |
108 | libdb_db_open = NULL; | |
109 | libdb_version = nodb; | |
110 | dlclose (libdb_handle); | |
111 | } | |
112 | } | |
113 | ||
114 | ||
115 | enum nss_status | |
116 | internal_setent (const char *file, NSS_DB **dbp) | |
117 | { | |
118 | enum nss_status status = NSS_STATUS_SUCCESS; | |
119 | int err; | |
120 | void *db; | |
cbc85992 UD |
121 | int fd; |
122 | int result; | |
123 | ||
9a6450d5 UD |
124 | |
125 | if (*dbp == NULL) | |
126 | { | |
127 | if (libdb_db_open == NULL) | |
128 | { | |
129 | __libc_lock_lock (lock); | |
130 | ||
131 | err = load_db (); | |
132 | ||
133 | __libc_lock_unlock (lock); | |
134 | ||
135 | if (err != 0) | |
136 | return NSS_STATUS_UNAVAIL; | |
137 | } | |
138 | ||
139 | /* Open the database. Fortunately this interface seems to be the | |
140 | same for all supported versions. */ | |
141 | err = DL_CALL_FCT (libdb_db_open, | |
142 | (file, DB_BTREE, DB_RDONLY, 0, NULL, NULL, &db)); | |
143 | ||
cbc85992 UD |
144 | if (err != 0) |
145 | { | |
146 | __set_errno (err); | |
147 | *dbp = NULL; | |
148 | return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL; | |
149 | } | |
150 | ||
9a6450d5 UD |
151 | /* Construct the object we pass up. */ |
152 | *dbp = (NSS_DB *) malloc (sizeof (NSS_DB)); | |
cbc85992 UD |
153 | if (*dbp == NULL) |
154 | return NSS_STATUS_UNAVAIL; | |
155 | ||
156 | (*dbp)->db = db; | |
157 | ||
158 | /* The functions are at different positions for the different | |
159 | versions. Sigh. */ | |
160 | switch (libdb_version) | |
9a6450d5 | 161 | { |
cbc85992 UD |
162 | case db24: |
163 | (*dbp)->close = | |
164 | (int (*) (void *, uint32_t)) ((struct db24 *) db)->close; | |
165 | (*dbp)->fd = | |
166 | (int (*) (void *, int *)) ((struct db24 *) db)->fd; | |
167 | (*dbp)->get = | |
168 | (int (*) (void *, void *, void *, void *, uint32_t)) | |
169 | ((struct db24 *) db)->get; | |
170 | break; | |
171 | case db27: | |
172 | (*dbp)->close = | |
173 | (int (*) (void *, uint32_t)) ((struct db27 *) db)->close; | |
174 | (*dbp)->fd = | |
175 | (int (*) (void *, int *)) ((struct db27 *) db)->fd; | |
176 | (*dbp)->get = | |
177 | (int (*) (void *, void *, void *, void *, uint32_t)) | |
178 | ((struct db27 *) db)->get; | |
179 | break; | |
180 | default: | |
181 | abort (); | |
9a6450d5 UD |
182 | } |
183 | ||
cbc85992 UD |
184 | /* We have to make sure the file is `closed on exec'. */ |
185 | err = DL_CALL_FCT ((*dbp)->fd, (db, &fd)); | |
9a6450d5 UD |
186 | if (err != 0) |
187 | { | |
188 | __set_errno (err); | |
cbc85992 | 189 | result = -1; |
9a6450d5 UD |
190 | } |
191 | else | |
192 | { | |
cbc85992 | 193 | int flags = result = fcntl (fd, F_GETFD, 0); |
9a6450d5 | 194 | |
cbc85992 | 195 | if (result >= 0) |
9a6450d5 | 196 | { |
cbc85992 UD |
197 | flags |= FD_CLOEXEC; |
198 | result = fcntl (fd, F_SETFD, flags); | |
9a6450d5 | 199 | } |
cbc85992 UD |
200 | } |
201 | if (result < 0) | |
202 | { | |
203 | /* Something went wrong. Close the stream and return a | |
204 | failure. */ | |
205 | DL_CALL_FCT ((*dbp)->close, (db, 0)); | |
206 | status = NSS_STATUS_UNAVAIL; | |
207 | free (*dbp); | |
208 | *dbp = NULL; | |
9a6450d5 UD |
209 | } |
210 | } | |
211 | ||
212 | return status; | |
213 | } | |
214 | ||
215 | ||
216 | /* Close the database file. */ | |
217 | void | |
218 | internal_endent (NSS_DB **dbp) | |
219 | { | |
220 | NSS_DB *db = *dbp; | |
221 | if (db != NULL) | |
222 | { | |
223 | DL_CALL_FCT (db->close, (db->db, 0)); | |
224 | *dbp = NULL; | |
225 | } | |
226 | } |