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805e021f CE |
1 | /* |
2 | * Copyright 2000, International Business Machines Corporation and others. | |
3 | * All Rights Reserved. | |
4 | * | |
5 | * This software has been released under the terms of the IBM Public | |
6 | * License. For details, see the LICENSE file in the top-level source | |
7 | * directory or online at http://www.openafs.org/dl/license10.html | |
8 | */ | |
9 | ||
10 | #include <afsconfig.h> | |
11 | #include <afs/param.h> | |
12 | ||
13 | #include <roken.h> | |
14 | ||
15 | #include <lwp.h> | |
16 | ||
17 | #include <lock.h> | |
18 | #include <afs/afsutil.h> | |
19 | ||
20 | #define UBIK_INTERNALS 1 | |
21 | #include "ubik.h" | |
22 | ||
23 | /*! \file | |
24 | * These routines are called via the proc ptr in the ubik_dbase structure. They provide access to | |
25 | * the physical disk, by converting the file numbers being processed ( >= 0 for user data space, < 0 | |
26 | * for ubik system files, such as the log) to actual pathnames to open, read, write, truncate, sync, | |
27 | * etc. | |
28 | */ | |
29 | ||
30 | #define MAXFDCACHE 4 | |
31 | static struct fdcache { | |
32 | int fd; | |
33 | int fileID; | |
34 | int refCount; | |
35 | } fdcache[MAXFDCACHE]; | |
36 | ||
37 | /* Cache a stdio handle for a given database file, for uphys_buf_append | |
38 | * operations. We only use buf_append for one file at a time, so only try to | |
39 | * cache a single file handle, since that's all we should need. */ | |
40 | static struct buf_fdcache { | |
41 | int fileID; | |
42 | FILE *stream; | |
43 | } buf_fdcache; | |
44 | ||
45 | static char pbuffer[1024]; | |
46 | ||
47 | static int uphys_buf_flush(struct ubik_dbase *adbase, afs_int32 afid); | |
48 | ||
49 | /*! | |
50 | * \warning Beware, when using this function, of the header in front of most files. | |
51 | */ | |
52 | static int | |
53 | uphys_open(struct ubik_dbase *adbase, afs_int32 afid) | |
54 | { | |
55 | int fd; | |
56 | static int initd; | |
57 | int i; | |
58 | struct fdcache *tfd; | |
59 | struct fdcache *bestfd; | |
60 | ||
61 | /* initialize package */ | |
62 | if (!initd) { | |
63 | initd = 1; | |
64 | tfd = fdcache; | |
65 | for (i = 0; i < MAXFDCACHE; tfd++, i++) { | |
66 | tfd->fd = -1; /* invalid value */ | |
67 | tfd->fileID = -10000; /* invalid value */ | |
68 | tfd->refCount = 0; | |
69 | } | |
70 | } | |
71 | ||
72 | /* scan file descr cache */ | |
73 | for (tfd = fdcache, i = 0; i < MAXFDCACHE; i++, tfd++) { | |
74 | if (afid == tfd->fileID && tfd->refCount == 0) { /* don't use open fd */ | |
75 | lseek(tfd->fd, 0, 0); /* reset ptr just like open would have */ | |
76 | tfd->refCount++; | |
77 | return tfd->fd; | |
78 | } | |
79 | } | |
80 | ||
81 | /* not found, open it and try to enter in cache */ | |
82 | snprintf(pbuffer, sizeof(pbuffer), "%s.DB%s%d", adbase->pathName, | |
83 | (afid<0)?"SYS":"", (afid<0)?-afid:afid); | |
84 | fd = open(pbuffer, O_CREAT | O_RDWR, 0600); | |
85 | if (fd < 0) { | |
86 | /* try opening read-only */ | |
87 | fd = open(pbuffer, O_RDONLY, 0); | |
88 | if (fd < 0) | |
89 | return fd; | |
90 | } | |
91 | ||
92 | /* enter it in the cache */ | |
93 | tfd = fdcache; | |
94 | bestfd = NULL; | |
95 | for (i = 0; i < MAXFDCACHE; i++, tfd++) { /* look for empty slot */ | |
96 | if (tfd->fd == -1) { | |
97 | bestfd = tfd; | |
98 | break; | |
99 | } | |
100 | } | |
101 | if (!bestfd) { /* look for reclaimable slot */ | |
102 | tfd = fdcache; | |
103 | for (i = 0; i < MAXFDCACHE; i++, tfd++) { | |
104 | if (tfd->refCount == 0) { | |
105 | bestfd = tfd; | |
106 | break; | |
107 | } | |
108 | } | |
109 | } | |
110 | if (bestfd) { /* found a usable slot */ | |
111 | tfd = bestfd; | |
112 | if (tfd->fd >= 0) | |
113 | close(tfd->fd); | |
114 | tfd->fd = fd; | |
115 | tfd->refCount = 1; /* us */ | |
116 | tfd->fileID = afid; | |
117 | } | |
118 | ||
119 | /* finally, we're done */ | |
120 | return fd; | |
121 | } | |
122 | ||
123 | /*! | |
124 | * \brief Close the file, maintaining ref count in cache structure. | |
125 | */ | |
126 | static int | |
127 | uphys_close(int afd) | |
128 | { | |
129 | int i; | |
130 | struct fdcache *tfd; | |
131 | ||
132 | if (afd < 0) | |
133 | return EBADF; | |
134 | tfd = fdcache; | |
135 | for (i = 0; i < MAXFDCACHE; i++, tfd++) { | |
136 | if (tfd->fd == afd) { | |
137 | if (tfd->fileID != -10000) { | |
138 | tfd->refCount--; | |
139 | return 0; | |
140 | } else { | |
141 | if (tfd->refCount > 0) { | |
142 | tfd->refCount--; | |
143 | if (tfd->refCount == 0) { | |
144 | close(tfd->fd); | |
145 | tfd->fd = -1; | |
146 | } | |
147 | return 0; | |
148 | } | |
149 | tfd->fd = -1; | |
150 | break; | |
151 | } | |
152 | } | |
153 | } | |
154 | return close(afd); | |
155 | } | |
156 | ||
157 | int | |
158 | uphys_stat(struct ubik_dbase *adbase, afs_int32 afid, struct ubik_stat *astat) | |
159 | { | |
160 | int fd; | |
161 | struct stat tstat; | |
162 | afs_int32 code; | |
163 | ||
164 | fd = uphys_open(adbase, afid); | |
165 | if (fd < 0) | |
166 | return fd; | |
167 | code = fstat(fd, &tstat); | |
168 | uphys_close(fd); | |
169 | if (code < 0) { | |
170 | return code; | |
171 | } | |
172 | code = tstat.st_size - HDRSIZE; | |
173 | if (code < 0) | |
174 | astat->size = 0; | |
175 | else | |
176 | astat->size = code; | |
177 | return 0; | |
178 | } | |
179 | ||
180 | int | |
181 | uphys_read(struct ubik_dbase *adbase, afs_int32 afile, | |
182 | void *abuffer, afs_int32 apos, afs_int32 alength) | |
183 | { | |
184 | int fd; | |
185 | afs_int32 code; | |
186 | ||
187 | fd = uphys_open(adbase, afile); | |
188 | if (fd < 0) | |
189 | return -1; | |
190 | code = lseek(fd, apos + HDRSIZE, 0); | |
191 | if (code < 0) { | |
192 | uphys_close(fd); | |
193 | return -1; | |
194 | } | |
195 | code = read(fd, abuffer, alength); | |
196 | uphys_close(fd); | |
197 | return code; | |
198 | } | |
199 | ||
200 | int | |
201 | uphys_write(struct ubik_dbase *adbase, afs_int32 afile, | |
202 | void *abuffer, afs_int32 apos, afs_int32 alength) | |
203 | { | |
204 | int fd; | |
205 | afs_int32 code; | |
206 | afs_int32 length; | |
207 | ||
208 | fd = uphys_open(adbase, afile); | |
209 | if (fd < 0) | |
210 | return -1; | |
211 | code = lseek(fd, apos + HDRSIZE, 0); | |
212 | if (code < 0) { | |
213 | uphys_close(fd); | |
214 | return -1; | |
215 | } | |
216 | length = write(fd, abuffer, alength); | |
217 | code = uphys_close(fd); | |
218 | if (code) | |
219 | return -1; | |
220 | else | |
221 | return length; | |
222 | } | |
223 | ||
224 | int | |
225 | uphys_truncate(struct ubik_dbase *adbase, afs_int32 afile, | |
226 | afs_int32 asize) | |
227 | { | |
228 | afs_int32 code, fd; | |
229 | ||
230 | /* Just in case there's memory-buffered data for this file, flush it before | |
231 | * truncating. */ | |
232 | if (uphys_buf_flush(adbase, afile) < 0) { | |
233 | return UIOERROR; | |
234 | } | |
235 | ||
236 | fd = uphys_open(adbase, afile); | |
237 | if (fd < 0) | |
238 | return UNOENT; | |
239 | code = ftruncate(fd, asize + HDRSIZE); | |
240 | uphys_close(fd); | |
241 | return code; | |
242 | } | |
243 | ||
244 | /*! | |
245 | * \brief Get number of dbase files. | |
246 | * | |
247 | * \todo Really should scan dir for data. | |
248 | */ | |
249 | int | |
250 | uphys_getnfiles(struct ubik_dbase *adbase) | |
251 | { | |
252 | /* really should scan dir for data */ | |
253 | return 1; | |
254 | } | |
255 | ||
256 | /*! | |
257 | * \brief Get database label, with \p aversion in host order. | |
258 | */ | |
259 | int | |
260 | uphys_getlabel(struct ubik_dbase *adbase, afs_int32 afile, | |
261 | struct ubik_version *aversion) | |
262 | { | |
263 | struct ubik_hdr thdr; | |
264 | afs_int32 code, fd; | |
265 | ||
266 | fd = uphys_open(adbase, afile); | |
267 | if (fd < 0) | |
268 | return UNOENT; | |
269 | code = read(fd, &thdr, sizeof(thdr)); | |
270 | if (code != sizeof(thdr)) { | |
271 | uphys_close(fd); | |
272 | return EIO; | |
273 | } | |
274 | aversion->epoch = ntohl(thdr.version.epoch); | |
275 | aversion->counter = ntohl(thdr.version.counter); | |
276 | uphys_close(fd); | |
277 | return 0; | |
278 | } | |
279 | ||
280 | /*! | |
281 | * \brief Label database, with \p aversion in host order. | |
282 | */ | |
283 | int | |
284 | uphys_setlabel(struct ubik_dbase *adbase, afs_int32 afile, | |
285 | struct ubik_version *aversion) | |
286 | { | |
287 | struct ubik_hdr thdr; | |
288 | afs_int32 code, fd; | |
289 | ||
290 | fd = uphys_open(adbase, afile); | |
291 | if (fd < 0) | |
292 | return UNOENT; | |
293 | ||
294 | memset(&thdr, 0, sizeof(thdr)); | |
295 | ||
296 | thdr.version.epoch = htonl(aversion->epoch); | |
297 | thdr.version.counter = htonl(aversion->counter); | |
298 | thdr.magic = htonl(UBIK_MAGIC); | |
299 | thdr.size = htons(HDRSIZE); | |
300 | code = write(fd, &thdr, sizeof(thdr)); | |
301 | fsync(fd); /* preserve over crash */ | |
302 | uphys_close(fd); | |
303 | if (code != sizeof(thdr)) { | |
304 | return EIO; | |
305 | } | |
306 | return 0; | |
307 | } | |
308 | ||
309 | int | |
310 | uphys_sync(struct ubik_dbase *adbase, afs_int32 afile) | |
311 | { | |
312 | afs_int32 code, fd; | |
313 | ||
314 | /* Flush any in-memory data, so we can sync it. */ | |
315 | if (uphys_buf_flush(adbase, afile) < 0) { | |
316 | return -1; | |
317 | } | |
318 | ||
319 | fd = uphys_open(adbase, afile); | |
320 | code = fsync(fd); | |
321 | uphys_close(fd); | |
322 | return code; | |
323 | } | |
324 | ||
325 | void | |
326 | uphys_invalidate(struct ubik_dbase *adbase, afs_int32 afid) | |
327 | { | |
328 | int i; | |
329 | struct fdcache *tfd; | |
330 | ||
331 | /* scan file descr cache */ | |
332 | for (tfd = fdcache, i = 0; i < MAXFDCACHE; i++, tfd++) { | |
333 | if (afid == tfd->fileID) { | |
334 | tfd->fileID = -10000; | |
335 | if (tfd->fd >= 0 && tfd->refCount == 0) { | |
336 | close(tfd->fd); | |
337 | tfd->fd = -1; | |
338 | } | |
339 | return; | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
344 | static FILE * | |
345 | uphys_buf_append_open(struct ubik_dbase *adbase, afs_int32 afid) | |
346 | { | |
347 | /* If we have a cached handle open for this file, just return it. */ | |
348 | if (buf_fdcache.stream && buf_fdcache.fileID == afid) { | |
349 | return buf_fdcache.stream; | |
350 | } | |
351 | ||
352 | /* Otherwise, close the existing handle, and open a new handle for the | |
353 | * given file. */ | |
354 | ||
355 | if (buf_fdcache.stream) { | |
356 | fclose(buf_fdcache.stream); | |
357 | } | |
358 | ||
359 | snprintf(pbuffer, sizeof(pbuffer), "%s.DB%s%d", adbase->pathName, | |
360 | (afid<0)?"SYS":"", (afid<0)?-afid:afid); | |
361 | buf_fdcache.stream = fopen(pbuffer, "a"); | |
362 | buf_fdcache.fileID = afid; | |
363 | return buf_fdcache.stream; | |
364 | } | |
365 | ||
366 | static int | |
367 | uphys_buf_flush(struct ubik_dbase *adbase, afs_int32 afid) | |
368 | { | |
369 | if (buf_fdcache.stream && buf_fdcache.fileID == afid) { | |
370 | int code = fflush(buf_fdcache.stream); | |
371 | if (code) { | |
372 | return -1; | |
373 | } | |
374 | } | |
375 | return 0; | |
376 | } | |
377 | ||
378 | /* Append the given data to the given database file, allowing the data to be | |
379 | * buffered in memory. */ | |
380 | int | |
381 | uphys_buf_append(struct ubik_dbase *adbase, afs_int32 afid, void *adata, | |
382 | afs_int32 alength) | |
383 | { | |
384 | FILE *stream; | |
385 | size_t code; | |
386 | ||
387 | stream = uphys_buf_append_open(adbase, afid); | |
388 | if (!stream) { | |
389 | return -1; | |
390 | } | |
391 | ||
392 | code = fwrite(adata, alength, 1, stream); | |
393 | if (code != 1) { | |
394 | return -1; | |
395 | } | |
396 | return alength; | |
397 | } |