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7de02494 | 1 | /* |
2 | * $Header$ | |
3 | * | |
4 | * Copyright (C) 1989, 1990 by the Massachusetts Institute of Technology | |
5 | * For copying and distribution information, please see the file | |
6 | * <mit-copyright.h>. | |
7 | */ | |
8 | ||
9 | #ifndef lint | |
10 | static char *rcsid_cache_dc = "$Header$"; | |
11 | #endif lint | |
12 | ||
13 | #include <mit-copyright.h> | |
14 | #include "query.h" | |
15 | #include "mr_server.h" | |
16 | EXEC SQL INCLUDE sqlca; | |
17 | ||
45bf7573 | 18 | EXEC SQL WHENEVER SQLERROR CALL ingerr; |
a49e54ea | 19 | |
7de02494 | 20 | extern char *whoami, *strsave(); |
21 | extern int ingres_errno, mr_errcode; | |
22 | ||
23 | ||
24 | /*** NOTE ************************************************************** | |
25 | * | |
26 | * This code depends on each type starting with a unique letter. If | |
27 | * any new types are added to the system that begin with the same | |
28 | * letter as one of the existing types: | |
29 | * User | |
30 | * List | |
31 | * String | |
32 | * Machine | |
33 | * Cluster | |
34 | * Filesystem | |
35 | * then we will have to rework the code that only looks at the first | |
36 | * letter of the types. | |
37 | * | |
38 | *********************************************************************** | |
39 | */ | |
40 | ||
41 | /* Cache parameters: */ | |
42 | #define CACHESIZE 101 /* number of cache slots */ | |
43 | #define NAMESZ 257 /* max size of a name */ | |
44 | ||
45 | struct item { | |
46 | char name[NAMESZ]; | |
47 | char type[9]; | |
48 | int nhash; | |
49 | int id; | |
50 | struct item *next; | |
51 | struct item *prev; | |
a49e54ea | 52 | struct item *trans; /* keep track of transactions */ |
7de02494 | 53 | }; |
54 | ||
55 | static struct item cachehead; | |
56 | static int cachesize; | |
57 | ||
58 | /* statistics counters */ | |
59 | int cachehits = 0, cachemisses = 0; | |
60 | ||
61 | ||
62 | /* Name hash function. */ | |
63 | ||
64 | int hashname(name, type) | |
65 | register char *name; | |
66 | char *type; | |
67 | { | |
68 | register int val = *type; | |
69 | ||
70 | while (*name) | |
71 | val = val<<5 - val + *name++ - '`'; | |
72 | return(val); | |
73 | } | |
74 | ||
75 | ||
76 | /* Initialize the cache, flushing any old data, and report the statistics | |
77 | * if the cache was previously in use. | |
78 | */ | |
79 | ||
80 | flush_cache() | |
81 | { | |
82 | register struct item *i; | |
83 | ||
84 | if (cachehits + cachemisses != 0) | |
85 | com_err(whoami, 0, "Flushing cache; %d hits, %d misses, %d%% hit rate", | |
86 | cachehits, cachemisses, | |
87 | (100 * cachehits) / (cachehits + cachemisses)); | |
88 | else | |
89 | cachehead.next = cachehead.prev = &cachehead; | |
90 | cachehits = cachemisses = cachesize = 0; | |
91 | for (i = cachehead.next; i != &cachehead; i = i->next) { | |
92 | if (i->prev != &cachehead) | |
93 | free(i->prev); | |
94 | } | |
95 | if (cachehead.prev != &cachehead) | |
96 | free(cachehead.prev); | |
97 | cachehead.next = cachehead.prev = &cachehead; | |
a49e54ea | 98 | cachehead.trans = (struct item *)NULL; |
7de02494 | 99 | } |
100 | ||
101 | ||
102 | /* Do a name to ID translation. id will be updated with the answer if | |
103 | * it is available, and as a side effect the cache is updated. | |
104 | */ | |
105 | ||
106 | int name_to_id(name, type, id) | |
107 | char *name; | |
108 | char *type; | |
109 | int *id; | |
110 | { | |
a49e54ea | 111 | register struct item *i, *t; |
7de02494 | 112 | EXEC SQL BEGIN DECLARE SECTION; |
4bd3537c | 113 | char *iname; |
7de02494 | 114 | int j, rowcount; |
115 | EXEC SQL END DECLARE SECTION; | |
116 | int h, ctr; | |
117 | ||
4bd3537c | 118 | h = hashname(name, type); |
7de02494 | 119 | for (i = cachehead.next; i != &cachehead; i = i->next) { |
120 | if (i->nhash != h || | |
4bd3537c | 121 | strcmp(name, i->name) || |
7de02494 | 122 | strcasecmp(type, i->type)) |
123 | continue; | |
124 | *id = i->id; | |
125 | cachehits++; | |
126 | i->next->prev = i->prev; | |
127 | i->prev->next = i->next; | |
128 | i->next = cachehead.next; | |
129 | i->prev = &cachehead; | |
130 | cachehead.next->prev = i; | |
131 | cachehead.next = i; | |
132 | return(MR_SUCCESS); | |
133 | } | |
134 | ||
135 | cachemisses++; | |
4bd3537c | 136 | iname = name; |
7de02494 | 137 | |
138 | switch (*type) { | |
139 | case 'U': | |
140 | case 'u': | |
cb8990ed | 141 | if (index(iname, '@') || (strlen(iname) > 8)) { |
06c1c8ff | 142 | sqlca.sqlcode = 100; |
143 | break; | |
144 | } | |
7de02494 | 145 | EXEC SQL SELECT users_id INTO :j FROM users WHERE login=:iname; |
146 | break; | |
147 | case 'L': | |
148 | case 'l': | |
149 | EXEC SQL SELECT list_id INTO :j FROM list WHERE name=:iname; | |
150 | break; | |
151 | case 'M': | |
152 | case 'm': | |
99e09b48 | 153 | EXEC SQL SELECT mach_id INTO :j FROM machine WHERE name=UPPERCASE(:iname); |
7de02494 | 154 | break; |
155 | case 'C': | |
156 | case 'c': | |
157 | EXEC SQL SELECT clu_id INTO :j FROM cluster WHERE name=:iname; | |
158 | break; | |
159 | case 'F': | |
160 | case 'f': | |
161 | EXEC SQL SELECT filsys_id INTO :j FROM filesys WHERE label=:iname; | |
162 | break; | |
163 | case 'S': | |
164 | case 's': | |
165 | EXEC SQL SELECT string_id INTO :j FROM strings WHERE string=:iname; | |
166 | break; | |
167 | default: | |
168 | return(MR_INTERNAL); | |
169 | } | |
170 | if (sqlca.sqlcode == 100) | |
171 | return(MR_NO_MATCH); | |
172 | if (sqlca.sqlerrd[2] > 1) | |
173 | return(MR_NOT_UNIQUE); | |
174 | if (sqlca.sqlcode != 0) | |
175 | return(MR_INGRES_ERR); | |
176 | *id = j; | |
4bd3537c | 177 | if (name[0] == '#' && !strcasecmp(type, "USER")) |
7de02494 | 178 | return(MR_SUCCESS); |
179 | if (cachesize < CACHESIZE) { | |
180 | i = (struct item *) malloc(sizeof(struct item)); | |
181 | cachesize++; | |
182 | } else { | |
183 | i = cachehead.prev; | |
184 | cachehead.prev = i->prev; | |
185 | i->prev->next = &cachehead; | |
186 | } | |
4bd3537c | 187 | strcpy(i->name, name); |
7de02494 | 188 | strcpy(i->type, type); |
189 | i->nhash = h; | |
190 | i->id = j; | |
191 | i->next = cachehead.next; | |
192 | i->prev = &cachehead; | |
193 | cachehead.next->prev = i; | |
194 | cachehead.next = i; | |
a49e54ea | 195 | /* find the end of the transaction chain & add this item */ |
196 | for (t = &cachehead; t->trans && t != i; t = t->trans); | |
197 | if (t != i) { | |
198 | t->trans = i; | |
199 | i->trans = (struct item *)NULL; | |
200 | } | |
7de02494 | 201 | return(MR_SUCCESS); |
202 | } | |
203 | ||
204 | ||
205 | /* Perform an ID to name mapping. name should be a pointer to a pointer to | |
206 | * malloc'ed data. The buffer it refers to will be freed, and a new buffer | |
207 | * allocated with the answer. | |
208 | */ | |
209 | ||
210 | int id_to_name(id, type, name) | |
211 | int id; | |
212 | char *type; | |
213 | char **name; | |
214 | { | |
45bf7573 | 215 | register struct item *i, *t; |
7de02494 | 216 | EXEC SQL BEGIN DECLARE SECTION; |
217 | char iname[NAMESZ]; | |
218 | int j, rowcount; | |
219 | EXEC SQL END DECLARE SECTION; | |
220 | int ctr; | |
221 | ||
222 | for (i = cachehead.next; i != &cachehead; i = i->next) { | |
223 | if (i->id != id || strcasecmp(type, i->type)) continue; | |
224 | free(*name); | |
225 | *name = strsave(i->name); | |
226 | cachehits++; | |
227 | i->next->prev = i->prev; | |
228 | i->prev->next = i->next; | |
229 | i->next = cachehead.next; | |
230 | i->prev = &cachehead; | |
231 | cachehead.next->prev = i; | |
232 | cachehead.next = i; | |
233 | return(MR_SUCCESS); | |
234 | } | |
235 | ||
236 | cachemisses++; | |
237 | j = id; | |
238 | ||
239 | switch (*type) { | |
240 | case 'U': | |
241 | case 'u': | |
a112f91e | 242 | EXEC SQL SELECT CHAR(login) INTO :iname FROM users WHERE users_id=:j; |
7de02494 | 243 | break; |
244 | case 'L': | |
245 | case 'l': | |
a112f91e | 246 | EXEC SQL SELECT CHAR(name) INTO :iname FROM list WHERE list_id=:j; |
7de02494 | 247 | break; |
248 | case 'M': | |
249 | case 'm': | |
a112f91e | 250 | EXEC SQL SELECT CHAR(name) INTO :iname FROM machine WHERE mach_id=:j; |
7de02494 | 251 | break; |
252 | case 'C': | |
253 | case 'c': | |
a112f91e | 254 | EXEC SQL SELECT CHAR(name) INTO :iname FROM cluster WHERE clu_id=:j; |
7de02494 | 255 | break; |
256 | case 'F': | |
257 | case 'f': | |
a112f91e | 258 | EXEC SQL SELECT CHAR(label) INTO :iname FROM filesys WHERE filsys_id=:j; |
7de02494 | 259 | break; |
260 | case 'S': | |
261 | case 's': | |
a112f91e | 262 | EXEC SQL SELECT CHAR(string) INTO :iname FROM strings WHERE string_id=:j; |
7de02494 | 263 | break; |
264 | default: | |
265 | return(MR_INTERNAL); | |
266 | } | |
267 | if (sqlca.sqlcode == 100) { | |
268 | free(*name); | |
269 | sprintf(iname, "#%d", j); | |
270 | *name = strsave(iname); | |
271 | return(MR_NO_MATCH); | |
272 | } | |
273 | if (sqlca.sqlerrd[2] > 1) | |
274 | return(MR_INTERNAL); | |
275 | if (sqlca.sqlcode != 0) | |
276 | return(MR_INGRES_ERR); | |
277 | free(*name); | |
278 | *name = strsave(strtrim(iname)); | |
279 | if (**name == '#' && !strcasecmp(type, "USER")) | |
280 | return(MR_SUCCESS); | |
281 | if (cachesize < CACHESIZE) { | |
282 | i = (struct item *) malloc(sizeof(struct item)); | |
283 | cachesize++; | |
284 | } else { | |
285 | i = cachehead.prev; | |
286 | cachehead.prev = i->prev; | |
287 | i->prev->next = &cachehead; | |
288 | } | |
289 | strcpy(i->name, *name); | |
290 | strcpy(i->type, type); | |
291 | i->nhash = hashname(*name, type); | |
292 | i->id = id; | |
293 | i->next = cachehead.next; | |
294 | i->prev = &cachehead; | |
295 | cachehead.next->prev = i; | |
296 | cachehead.next = i; | |
a49e54ea | 297 | /* find the end of the transaction chain & add this item */ |
298 | for (t = &cachehead; t->trans && t != i; t = t->trans); | |
299 | if (t != i) { | |
300 | t->trans = i; | |
301 | i->trans = (struct item *)NULL; | |
302 | } | |
7de02494 | 303 | return(MR_SUCCESS); |
304 | } | |
305 | ||
306 | ||
307 | /* Explicitly add something to the cache without doing a lookup in the | |
308 | * database. | |
309 | */ | |
310 | ||
311 | cache_entry(name, type, id) | |
312 | char *name; | |
313 | char *type; | |
314 | int id; | |
315 | { | |
a49e54ea | 316 | register struct item *i, *t; |
7de02494 | 317 | |
318 | for (i = cachehead.next; i != &cachehead; i = i->next) | |
a49e54ea | 319 | if (i->id == id && !strcmp(i->type, type)) { |
320 | if (strcmp(i->name, name)) { | |
321 | strcpy(i->name, name); | |
322 | i->nhash = hashname(name, type); | |
323 | } | |
324 | return(MR_SUCCESS); | |
325 | } | |
7de02494 | 326 | if (cachesize < CACHESIZE) { |
327 | i = (struct item *) malloc(sizeof(struct item)); | |
328 | cachesize++; | |
329 | } else { | |
330 | i = cachehead.prev; | |
331 | cachehead.prev = i->prev; | |
332 | i->prev->next = &cachehead; | |
333 | } | |
334 | strcpy(i->name, name); | |
335 | strcpy(i->type, type); | |
336 | i->nhash = hashname(name, type); | |
337 | i->id = id; | |
338 | i->next = cachehead.next; | |
339 | i->prev = &cachehead; | |
340 | cachehead.next->prev = i; | |
341 | cachehead.next = i; | |
a49e54ea | 342 | /* find the end of the transaction chain & add this item */ |
343 | for (t = &cachehead; t->trans && t != i; t = t->trans); | |
344 | if (t != i) { | |
345 | t->trans = i; | |
346 | i->trans = (struct item *)NULL; | |
347 | } | |
7de02494 | 348 | return(MR_SUCCESS); |
349 | } | |
350 | ||
351 | ||
352 | /* Flush something that may or may not already be in the cache. */ | |
353 | ||
354 | flush_name(name, type) | |
355 | char *name; | |
356 | char *type; | |
357 | { | |
358 | int h; | |
359 | register struct item *i; | |
360 | ||
361 | h = hashname(name, type); | |
362 | ||
363 | for (i = cachehead.next; i != &cachehead; i = i->next) { | |
364 | if (!strcmp(name, i->name) && !strcasecmp(type, i->type)) { | |
365 | cachesize--; | |
366 | i->next->prev = i->prev; | |
367 | i->prev->next = i->next; | |
368 | free(i); | |
369 | return(MR_SUCCESS); | |
370 | } | |
371 | } | |
372 | } | |
a49e54ea | 373 | |
374 | ||
375 | /* Called when a transaction is committed to also commit any cache changes. | |
376 | * Just throws away the list of cache changes for this transaction. | |
377 | */ | |
378 | ||
379 | cache_commit() | |
380 | { | |
381 | cachehead.trans = (struct item *)NULL; | |
382 | } | |
383 | ||
384 | ||
385 | /* Called whan a transaction is aborted to throw away any cache changes | |
386 | * from that transaction. | |
387 | */ | |
388 | ||
389 | cache_abort() | |
390 | { | |
391 | register struct item *i, *t; | |
392 | ||
393 | for (i = cachehead.trans; i; i = t) { | |
394 | t = i->trans; | |
395 | flush_name(i->name, i->type); | |
396 | } | |
397 | cachehead.trans = (struct item *)NULL; | |
398 | } |