source: vendor/3.5.4/source3/modules/vfs_preopen.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 9.6 KB
Line 
1/*
2 * Force a readahead of files by opening them and reading the first bytes
3 *
4 * Copyright (C) Volker Lendecke 2008
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include "includes.h"
22
23struct preopen_state;
24
25struct preopen_helper {
26 struct preopen_state *state;
27 struct fd_event *fde;
28 pid_t pid;
29 int fd;
30 bool busy;
31};
32
33struct preopen_state {
34 int num_helpers;
35 struct preopen_helper *helpers;
36
37 size_t to_read; /* How many bytes to read in children? */
38 int queue_max;
39
40 char *template_fname; /* Filename to be sent to children */
41 size_t number_start; /* start offset into "template_fname" */
42 int num_digits; /* How many digits is the number long? */
43
44 int fnum_sent; /* last fname sent to children */
45
46 int fnum_queue_end; /* last fname to be sent, based on
47 * last open call + preopen:queuelen
48 */
49
50 name_compare_entry *preopen_names;
51};
52
53static void preopen_helper_destroy(struct preopen_helper *c)
54{
55 int status;
56 close(c->fd);
57 c->fd = -1;
58 kill(c->pid, SIGKILL);
59 waitpid(c->pid, &status, 0);
60 c->busy = true;
61}
62
63static void preopen_queue_run(struct preopen_state *state)
64{
65 char *pdelimiter;
66 char delimiter;
67
68 pdelimiter = state->template_fname + state->number_start
69 + state->num_digits;
70 delimiter = *pdelimiter;
71
72 while (state->fnum_sent < state->fnum_queue_end) {
73
74 ssize_t written;
75 size_t to_write;
76 int helper;
77
78 for (helper=0; helper<state->num_helpers; helper++) {
79 if (state->helpers[helper].busy) {
80 continue;
81 }
82 break;
83 }
84 if (helper == state->num_helpers) {
85 /* everyone is busy */
86 return;
87 }
88
89 snprintf(state->template_fname + state->number_start,
90 state->num_digits + 1,
91 "%.*lu", state->num_digits,
92 (long unsigned int)(state->fnum_sent + 1));
93 *pdelimiter = delimiter;
94
95 to_write = talloc_get_size(state->template_fname);
96 written = write_data(state->helpers[helper].fd,
97 state->template_fname, to_write);
98 state->helpers[helper].busy = true;
99
100 if (written != to_write) {
101 preopen_helper_destroy(&state->helpers[helper]);
102 }
103 state->fnum_sent += 1;
104 }
105}
106
107static void preopen_helper_readable(struct event_context *ev,
108 struct fd_event *fde, uint16_t flags,
109 void *priv)
110{
111 struct preopen_helper *helper = (struct preopen_helper *)priv;
112 struct preopen_state *state = helper->state;
113 ssize_t nread;
114 char c;
115
116 if ((flags & EVENT_FD_READ) == 0) {
117 return;
118 }
119
120 nread = read(helper->fd, &c, 1);
121 if (nread <= 0) {
122 preopen_helper_destroy(helper);
123 return;
124 }
125
126 helper->busy = false;
127
128 preopen_queue_run(state);
129}
130
131static int preopen_helpers_destructor(struct preopen_state *c)
132{
133 int i;
134
135 for (i=0; i<c->num_helpers; i++) {
136 if (c->helpers[i].fd == -1) {
137 continue;
138 }
139 preopen_helper_destroy(&c->helpers[i]);
140 }
141
142 return 0;
143}
144
145static bool preopen_helper_open_one(int sock_fd, char **pnamebuf,
146 size_t to_read, void *filebuf)
147{
148 char *namebuf = *pnamebuf;
149 ssize_t nwritten, nread;
150 char c = 0;
151 int fd;
152
153 nread = 0;
154
155 while ((nread == 0) || (namebuf[nread-1] != '\0')) {
156 ssize_t thistime;
157
158 thistime = read(sock_fd, namebuf + nread,
159 talloc_get_size(namebuf) - nread);
160 if (thistime <= 0) {
161 return false;
162 }
163
164 nread += thistime;
165
166 if (nread == talloc_get_size(namebuf)) {
167 namebuf = TALLOC_REALLOC_ARRAY(
168 NULL, namebuf, char,
169 talloc_get_size(namebuf) * 2);
170 if (namebuf == NULL) {
171 return false;
172 }
173 *pnamebuf = namebuf;
174 }
175 }
176
177 fd = open(namebuf, O_RDONLY);
178 if (fd == -1) {
179 goto done;
180 }
181 nread = read(fd, filebuf, to_read);
182 close(fd);
183
184 done:
185 nwritten = write(sock_fd, &c, 1);
186 return true;
187}
188
189static bool preopen_helper(int fd, size_t to_read)
190{
191 char *namebuf;
192 void *readbuf;
193
194 namebuf = TALLOC_ARRAY(NULL, char, 1024);
195 if (namebuf == NULL) {
196 return false;
197 }
198
199 readbuf = talloc_size(NULL, to_read);
200 if (readbuf == NULL) {
201 TALLOC_FREE(namebuf);
202 return false;
203 }
204
205 while (preopen_helper_open_one(fd, &namebuf, to_read, readbuf)) {
206 ;
207 }
208
209 TALLOC_FREE(readbuf);
210 TALLOC_FREE(namebuf);
211 return false;
212}
213
214static NTSTATUS preopen_init_helper(struct preopen_helper *h)
215{
216 int fdpair[2];
217 NTSTATUS status;
218
219 if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
220 status = map_nt_error_from_unix(errno);
221 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
222 return status;
223 }
224
225 h->pid = sys_fork();
226
227 if (h->pid == -1) {
228 return map_nt_error_from_unix(errno);
229 }
230
231 if (h->pid == 0) {
232 close(fdpair[0]);
233 preopen_helper(fdpair[1], h->state->to_read);
234 exit(0);
235 }
236 close(fdpair[1]);
237 h->fd = fdpair[0];
238 h->fde = event_add_fd(smbd_event_context(), h->state, h->fd,
239 EVENT_FD_READ, preopen_helper_readable, h);
240 if (h->fde == NULL) {
241 close(h->fd);
242 h->fd = -1;
243 return NT_STATUS_NO_MEMORY;
244 }
245 h->busy = false;
246 return NT_STATUS_OK;
247}
248
249static NTSTATUS preopen_init_helpers(TALLOC_CTX *mem_ctx, size_t to_read,
250 int num_helpers, int queue_max,
251 struct preopen_state **presult)
252{
253 struct preopen_state *result;
254 int i;
255
256 result = talloc(mem_ctx, struct preopen_state);
257 if (result == NULL) {
258 return NT_STATUS_NO_MEMORY;
259 }
260
261 result->num_helpers = num_helpers;
262 result->helpers = TALLOC_ARRAY(result, struct preopen_helper,
263 num_helpers);
264 if (result->helpers == NULL) {
265 TALLOC_FREE(result);
266 return NT_STATUS_NO_MEMORY;
267 }
268
269 result->to_read = to_read;
270 result->queue_max = queue_max;
271 result->template_fname = NULL;
272 result->fnum_sent = 0;
273
274 for (i=0; i<num_helpers; i++) {
275 result->helpers[i].state = result;
276 result->helpers[i].fd = -1;
277 }
278
279 talloc_set_destructor(result, preopen_helpers_destructor);
280
281 for (i=0; i<num_helpers; i++) {
282 preopen_init_helper(&result->helpers[i]);
283 }
284
285 *presult = result;
286 return NT_STATUS_OK;
287}
288
289static void preopen_free_helpers(void **ptr)
290{
291 TALLOC_FREE(*ptr);
292}
293
294static struct preopen_state *preopen_state_get(vfs_handle_struct *handle)
295{
296 struct preopen_state *state;
297 NTSTATUS status;
298 const char *namelist;
299
300 if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
301 SMB_VFS_HANDLE_GET_DATA(handle, state, struct preopen_state,
302 return NULL);
303 return state;
304 }
305
306 namelist = lp_parm_const_string(SNUM(handle->conn), "preopen", "names",
307 NULL);
308
309 if (namelist == NULL) {
310 return NULL;
311 }
312
313 status = preopen_init_helpers(
314 NULL,
315 lp_parm_int(SNUM(handle->conn), "preopen", "num_bytes", 1),
316 lp_parm_int(SNUM(handle->conn), "preopen", "helpers", 1),
317 lp_parm_int(SNUM(handle->conn), "preopen", "queuelen", 10),
318 &state);
319 if (!NT_STATUS_IS_OK(status)) {
320 return NULL;
321 }
322
323 set_namearray(&state->preopen_names, (char *)namelist);
324
325 if (state->preopen_names == NULL) {
326 TALLOC_FREE(state);
327 return NULL;
328 }
329
330 if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
331 SMB_VFS_HANDLE_SET_DATA(handle, state, preopen_free_helpers,
332 struct preopen_state, return NULL);
333 }
334
335 return state;
336}
337
338static bool preopen_parse_fname(const char *fname, unsigned long *pnum,
339 size_t *pstart_idx, int *pnum_digits)
340{
341 const char *p, *q;
342 unsigned long num;
343
344 p = strrchr_m(fname, '/');
345 if (p == NULL) {
346 p = fname;
347 }
348
349 p += 1;
350 while (p[0] != '\0') {
351 if (isdigit(p[0]) && isdigit(p[1]) && isdigit(p[2])) {
352 break;
353 }
354 p += 1;
355 }
356 if (*p == '\0') {
357 /* no digits around */
358 return false;
359 }
360
361 num = strtoul(p, (char **)&q, 10);
362
363 if (num+1 < num) {
364 /* overflow */
365 return false;
366 }
367
368 *pnum = num;
369 *pstart_idx = (p - fname);
370 *pnum_digits = (q - p);
371 return true;
372}
373
374static int preopen_open(vfs_handle_struct *handle,
375 struct smb_filename *smb_fname, files_struct *fsp,
376 int flags, mode_t mode)
377{
378 struct preopen_state *state;
379 int res;
380 unsigned long num;
381
382 DEBUG(10, ("preopen_open called on %s\n", smb_fname_str_dbg(smb_fname)));
383
384 state = preopen_state_get(handle);
385 if (state == NULL) {
386 return SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode);
387 }
388
389 res = SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode);
390 if (res == -1) {
391 return -1;
392 }
393
394 if (flags != O_RDONLY) {
395 return res;
396 }
397
398 if (!is_in_path(smb_fname->base_name, state->preopen_names, true)) {
399 DEBUG(10, ("%s does not match the preopen:names list\n",
400 smb_fname_str_dbg(smb_fname)));
401 return res;
402 }
403
404 TALLOC_FREE(state->template_fname);
405 state->template_fname = talloc_asprintf(
406 state, "%s/%s", fsp->conn->connectpath, smb_fname->base_name);
407
408 if (state->template_fname == NULL) {
409 return res;
410 }
411
412 if (!preopen_parse_fname(state->template_fname, &num,
413 &state->number_start, &state->num_digits)) {
414 TALLOC_FREE(state->template_fname);
415 return res;
416 }
417
418 if (num > state->fnum_sent) {
419 /*
420 * Helpers were too slow, there's no point in reading
421 * files in helpers that we already read in the
422 * parent.
423 */
424 state->fnum_sent = num;
425 }
426
427 if ((state->fnum_queue_end != 0) /* Something was started earlier */
428 && (num < (state->fnum_queue_end - state->queue_max))) {
429 /*
430 * "num" is before the queue we announced. This means
431 * a new run is started.
432 */
433 state->fnum_sent = num;
434 }
435
436 state->fnum_queue_end = num + state->queue_max;
437
438 preopen_queue_run(state);
439
440 return res;
441}
442
443static struct vfs_fn_pointers vfs_preopen_fns = {
444 .open = preopen_open
445};
446
447NTSTATUS vfs_preopen_init(void);
448NTSTATUS vfs_preopen_init(void)
449{
450 return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
451 "preopen", &vfs_preopen_fns);
452}
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