2 * This file contains a set of abstractions that allow Citadel to plug into any
3 * record manager or database system for its data store.
9 * Note that each call to a GDBM function is wrapped in an S_DATABASE critical
10 * section. This is done because GDBM is not threadsafe. This is the ONLY
11 * place in the entire Citadel server where any code enters two different
12 * classes of critical sections at the same time; this is why the GDBM calls
13 * are *tightly* wrapped in S_DATABASE. Opening multiple concurrent critical
14 * sections elsewhere in the code can, and probably will, cause deadlock
15 * conditions to occur. (Deadlock is bad. Eliminate.)
35 #include "sysdep_decls.h"
39 * This array holds one gdbm handle for each Citadel database.
41 GDBM_FILE gdbms[MAXCDB];
44 * We also keep these around, for sequential searches... (one per
45 * session. Maybe there's a better way?)
52 * Reclaim unused space in the databases. We need to do each one of
53 * these discretely, rather than in a loop.
55 void defrag_databases(void) {
57 /* defrag the message base */
58 begin_critical_section(S_MSGMAIN);
59 begin_critical_section(S_DATABASE);
60 gdbm_reorganize(gdbms[CDB_MSGMAIN]);
61 end_critical_section(S_DATABASE);
62 end_critical_section(S_MSGMAIN);
64 /* defrag the user file, mailboxes, and user/room relationships */
65 begin_critical_section(S_USERSUPP);
66 begin_critical_section(S_DATABASE);
67 gdbm_reorganize(gdbms[CDB_USERSUPP]);
68 gdbm_reorganize(gdbms[CDB_VISIT]);
69 end_critical_section(S_DATABASE);
70 end_critical_section(S_USERSUPP);
72 /* defrag the room files and message lists */
73 begin_critical_section(S_QUICKROOM);
74 begin_critical_section(S_DATABASE);
75 gdbm_reorganize(gdbms[CDB_QUICKROOM]);
76 gdbm_reorganize(gdbms[CDB_MSGLISTS]);
77 end_critical_section(S_DATABASE);
78 end_critical_section(S_QUICKROOM);
80 /* defrag the floor table */
81 begin_critical_section(S_FLOORTAB);
82 begin_critical_section(S_DATABASE);
83 gdbm_reorganize(gdbms[CDB_FLOORTAB]);
84 end_critical_section(S_DATABASE);
85 end_critical_section(S_FLOORTAB);
90 * Open the various gdbm databases we'll be using. Any database which
91 * does not exist should be created.
93 void open_databases(void) {
97 * Silently try to create the database subdirectory. If it's
98 * already there, no problem.
100 system("exec mkdir data 2>/dev/null");
102 /* a critical section is unnecessary, as this function is called before
103 any other threads are created. and it causes problems on BSDI.
105 begin_critical_section(S_DATABASE);
109 gdbms[CDB_MSGMAIN] = gdbm_open("data/msgmain.gdbm", 8192,
110 GDBM_WRCREAT, 0600, NULL);
111 if (gdbms[CDB_MSGMAIN] == NULL) {
112 lprintf(2, "Cannot open msgmain: %s\n",
113 gdbm_strerror(gdbm_errno));
116 gdbms[CDB_USERSUPP] = gdbm_open("data/usersupp.gdbm", 0,
117 GDBM_WRCREAT, 0600, NULL);
118 if (gdbms[CDB_USERSUPP] == NULL) {
119 lprintf(2, "Cannot open usersupp: %s\n",
120 gdbm_strerror(gdbm_errno));
123 gdbms[CDB_VISIT] = gdbm_open("data/visit.gdbm", 0,
124 GDBM_WRCREAT, 0600, NULL);
125 if (gdbms[CDB_VISIT] == NULL) {
126 lprintf(2, "Cannot open visit file: %s\n",
127 gdbm_strerror(gdbm_errno));
130 gdbms[CDB_QUICKROOM] = gdbm_open("data/quickroom.gdbm", 0,
131 GDBM_WRCREAT, 0600, NULL);
132 if (gdbms[CDB_QUICKROOM] == NULL) {
133 lprintf(2, "Cannot open quickroom: %s\n",
134 gdbm_strerror(gdbm_errno));
137 gdbms[CDB_FLOORTAB] = gdbm_open("data/floortab.gdbm", 0,
138 GDBM_WRCREAT, 0600, NULL);
139 if (gdbms[CDB_FLOORTAB] == NULL) {
140 lprintf(2, "Cannot open floortab: %s\n",
141 gdbm_strerror(gdbm_errno));
144 gdbms[CDB_MSGLISTS] = gdbm_open("data/msglists.gdbm", 0,
145 GDBM_WRCREAT, 0600, NULL);
146 if (gdbms[CDB_MSGLISTS] == NULL) {
147 lprintf(2, "Cannot open msglists: %s\n",
148 gdbm_strerror(gdbm_errno));
151 for (a=0; a<MAXKEYS; ++a) {
153 dtkey[a].dptr = NULL;
157 end_critical_section(S_DATABASE);
164 * Close all of the gdbm database files we've opened. This can be done
165 * in a loop, since it's just a bunch of closes.
167 void close_databases(void) {
170 /* Hmm... we should decide when would be a good time to defrag.
171 * Server shutdowns might be an opportune time.
175 begin_critical_section(S_DATABASE);
176 for (a=0; a<MAXCDB; ++a) {
177 lprintf(7, "Closing database %d\n", a);
178 gdbm_close(gdbms[a]);
180 end_critical_section(S_DATABASE);
182 for (a=0; a<MAXKEYS; ++a) {
183 if (dtkey[a].dptr != NULL) {
184 phree(dtkey[a].dptr);
192 * Store a piece of data. Returns 0 if the operation was successful. If a
193 * datum already exists it should be overwritten.
195 int cdb_store(int cdb,
196 void *key, int keylen,
197 void *data, int datalen) {
204 ddata.dsize = datalen;
207 begin_critical_section(S_DATABASE);
208 retval = gdbm_store(gdbms[cdb], dkey, ddata, GDBM_REPLACE);
209 end_critical_section(S_DATABASE);
211 lprintf(2, "gdbm error: %s\n", gdbm_strerror(gdbm_errno));
220 * Delete a piece of data. Returns 0 if the operation was successful.
222 int cdb_delete(int cdb, void *key, int keylen) {
230 begin_critical_section(S_DATABASE);
231 retval = gdbm_delete(gdbms[cdb], dkey);
232 end_critical_section(S_DATABASE);
241 * Fetch a piece of data. If not found, returns NULL. Otherwise, it returns
242 * a struct cdbdata which it is the caller's responsibility to free later on
243 * using the cdb_free() routine.
245 struct cdbdata *cdb_fetch(int cdb, void *key, int keylen) {
247 struct cdbdata *tempcdb;
253 begin_critical_section(S_DATABASE);
254 dret = gdbm_fetch(gdbms[cdb], dkey);
255 end_critical_section(S_DATABASE);
256 if (dret.dptr == NULL) {
260 tempcdb = (struct cdbdata *) mallok(sizeof(struct cdbdata));
261 if (tempcdb == NULL) {
262 lprintf(2, "Cannot allocate memory!\n");
265 tempcdb->len = dret.dsize;
266 tempcdb->ptr = dret.dptr;
272 * Free a cdbdata item (ok, this is really no big deal, but we might need to do
273 * more complex stuff with other database managers in the future).
275 void cdb_free(struct cdbdata *cdb) {
282 * Prepare for a sequential search of an entire database. (In the gdbm model,
283 * we do this by keeping an array dtkey[] of "the next" key for each session
284 * that is open. There is guaranteed to be no more than one traversal in
285 * progress per session at any given time.)
287 void cdb_rewind(int cdb) {
289 if (dtkey[CC->cs_pid].dptr != NULL) {
290 phree(dtkey[CC->cs_pid].dptr);
293 begin_critical_section(S_DATABASE);
294 dtkey[CC->cs_pid] = gdbm_firstkey(gdbms[cdb]);
295 end_critical_section(S_DATABASE);
300 * Fetch the next item in a sequential search. Returns a pointer to a
301 * cdbdata structure, or NULL if we've hit the end.
303 struct cdbdata *cdb_next_item(int cdb) {
305 struct cdbdata *cdbret;
308 if (dtkey[CC->cs_pid].dptr == NULL) { /* end of file */
312 begin_critical_section(S_DATABASE);
313 dret = gdbm_fetch(gdbms[cdb], dtkey[CC->cs_pid]);
314 end_critical_section(S_DATABASE);
315 if (dret.dptr == NULL) { /* bad read */
316 phree(dtkey[CC->cs_pid].dptr);
320 cdbret = (struct cdbdata *) mallok(sizeof(struct cdbdata));
321 cdbret->len = dret.dsize;
322 cdbret->ptr = dret.dptr;
324 begin_critical_section(S_DATABASE);
325 dtkey[CC->cs_pid] = gdbm_nextkey(gdbms[cdb], dtkey[CC->cs_pid]);
326 end_critical_section(S_DATABASE);