2 * Force a readahead of files by opening them and reading the first bytes
4 * Copyright (C) Volker Lendecke 2008
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.
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.
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.
22 #include "system/filesys.h"
23 #include "smbd/smbd.h"
24 #include "lib/util/sys_rw.h"
25 #include "lib/util/sys_rw_data.h"
29 struct preopen_helper {
30 struct preopen_state *state;
31 struct tevent_fd *fde;
37 struct preopen_state {
39 struct preopen_helper *helpers;
41 size_t to_read; /* How many bytes to read in children? */
44 char *template_fname; /* Filename to be sent to children */
45 size_t number_start; /* start offset into "template_fname" */
46 int num_digits; /* How many digits is the number long? */
48 int fnum_sent; /* last fname sent to children */
50 int fnum_queue_end; /* last fname to be sent, based on
51 * last open call + preopen:queuelen
54 name_compare_entry *preopen_names;
57 static void preopen_helper_destroy(struct preopen_helper *c)
63 kill(c->pid, SIGKILL);
64 waitpid(c->pid, &status, 0);
68 static void preopen_queue_run(struct preopen_state *state)
73 pdelimiter = state->template_fname + state->number_start
75 delimiter = *pdelimiter;
77 while (state->fnum_sent < state->fnum_queue_end) {
83 for (helper=0; helper<state->num_helpers; helper++) {
84 if (state->helpers[helper].busy) {
89 if (helper == state->num_helpers) {
90 /* everyone is busy */
94 snprintf(state->template_fname + state->number_start,
95 state->num_digits + 1,
96 "%.*lu", state->num_digits,
97 (long unsigned int)(state->fnum_sent + 1));
98 *pdelimiter = delimiter;
100 to_write = talloc_get_size(state->template_fname);
101 written = write_data(state->helpers[helper].fd,
102 state->template_fname, to_write);
103 state->helpers[helper].busy = true;
105 if (written != to_write) {
106 preopen_helper_destroy(&state->helpers[helper]);
108 state->fnum_sent += 1;
112 static void preopen_helper_readable(struct tevent_context *ev,
113 struct tevent_fd *fde, uint16_t flags,
116 struct preopen_helper *helper = (struct preopen_helper *)priv;
117 struct preopen_state *state = helper->state;
121 if ((flags & TEVENT_FD_READ) == 0) {
125 nread = read(helper->fd, &c, 1);
127 preopen_helper_destroy(helper);
131 helper->busy = false;
133 preopen_queue_run(state);
136 static int preopen_helpers_destructor(struct preopen_state *c)
140 for (i=0; i<c->num_helpers; i++) {
141 if (c->helpers[i].fd == -1) {
144 preopen_helper_destroy(&c->helpers[i]);
150 static bool preopen_helper_open_one(int sock_fd, char **pnamebuf,
151 size_t to_read, void *filebuf)
153 char *namebuf = *pnamebuf;
163 thistime = read(sock_fd, namebuf + nread,
164 talloc_get_size(namebuf) - nread);
171 if (nread == talloc_get_size(namebuf)) {
172 namebuf = talloc_realloc(
174 talloc_get_size(namebuf) * 2);
175 if (namebuf == NULL) {
180 } while (namebuf[nread - 1] != '\0');
182 fd = open(namebuf, O_RDONLY);
186 nread = read(fd, filebuf, to_read);
190 sys_write_v(sock_fd, &c, 1);
194 static bool preopen_helper(int fd, size_t to_read)
199 namebuf = talloc_array(NULL, char, 1024);
200 if (namebuf == NULL) {
204 readbuf = talloc_size(NULL, to_read);
205 if (readbuf == NULL) {
206 TALLOC_FREE(namebuf);
210 while (preopen_helper_open_one(fd, &namebuf, to_read, readbuf)) {
214 TALLOC_FREE(readbuf);
215 TALLOC_FREE(namebuf);
219 static NTSTATUS preopen_init_helper(struct preopen_helper *h)
224 if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
225 status = map_nt_error_from_unix(errno);
226 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
233 return map_nt_error_from_unix(errno);
238 preopen_helper(fdpair[1], h->state->to_read);
243 h->fde = tevent_add_fd(global_event_context(), h->state, h->fd,
244 TEVENT_FD_READ, preopen_helper_readable, h);
245 if (h->fde == NULL) {
248 return NT_STATUS_NO_MEMORY;
254 static NTSTATUS preopen_init_helpers(TALLOC_CTX *mem_ctx, size_t to_read,
255 int num_helpers, int queue_max,
256 struct preopen_state **presult)
258 struct preopen_state *result;
261 result = talloc(mem_ctx, struct preopen_state);
262 if (result == NULL) {
263 return NT_STATUS_NO_MEMORY;
266 result->num_helpers = num_helpers;
267 result->helpers = talloc_array(result, struct preopen_helper,
269 if (result->helpers == NULL) {
271 return NT_STATUS_NO_MEMORY;
274 result->to_read = to_read;
275 result->queue_max = queue_max;
276 result->template_fname = NULL;
277 result->fnum_sent = 0;
278 result->fnum_queue_end = 0;
280 for (i=0; i<num_helpers; i++) {
281 result->helpers[i].state = result;
282 result->helpers[i].fd = -1;
285 talloc_set_destructor(result, preopen_helpers_destructor);
287 for (i=0; i<num_helpers; i++) {
288 preopen_init_helper(&result->helpers[i]);
295 static void preopen_free_helpers(void **ptr)
300 static struct preopen_state *preopen_state_get(vfs_handle_struct *handle)
302 struct preopen_state *state;
304 const char *namelist;
306 if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
307 SMB_VFS_HANDLE_GET_DATA(handle, state, struct preopen_state,
312 namelist = lp_parm_const_string(SNUM(handle->conn), "preopen", "names",
315 if (namelist == NULL) {
319 status = preopen_init_helpers(
321 lp_parm_int(SNUM(handle->conn), "preopen", "num_bytes", 1),
322 lp_parm_int(SNUM(handle->conn), "preopen", "helpers", 1),
323 lp_parm_int(SNUM(handle->conn), "preopen", "queuelen", 10),
325 if (!NT_STATUS_IS_OK(status)) {
329 set_namearray(&state->preopen_names, namelist);
331 if (state->preopen_names == NULL) {
336 if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
337 SMB_VFS_HANDLE_SET_DATA(handle, state, preopen_free_helpers,
338 struct preopen_state, return NULL);
344 static bool preopen_parse_fname(const char *fname, unsigned long *pnum,
345 size_t *pstart_idx, int *pnum_digits)
352 p = strrchr_m(fname, '/');
358 while (p[0] != '\0') {
359 if (isdigit(p[0]) && isdigit(p[1]) && isdigit(p[2])) {
365 /* no digits around */
369 num = smb_strtoul(p, (char **)&q, 10, &error, SMB_STR_STANDARD);
380 *pstart_idx = (p - fname);
381 *pnum_digits = (q - p);
385 static int preopen_open(vfs_handle_struct *handle,
386 struct smb_filename *smb_fname, files_struct *fsp,
387 int flags, mode_t mode)
389 struct preopen_state *state;
393 DEBUG(10, ("preopen_open called on %s\n", smb_fname_str_dbg(smb_fname)));
395 state = preopen_state_get(handle);
397 return SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode);
400 res = SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode);
405 if ((flags & O_ACCMODE) != O_RDONLY) {
409 if (!is_in_path(smb_fname->base_name, state->preopen_names, true)) {
410 DEBUG(10, ("%s does not match the preopen:names list\n",
411 smb_fname_str_dbg(smb_fname)));
415 TALLOC_FREE(state->template_fname);
416 state->template_fname = talloc_asprintf(
418 fsp->conn->cwd_fsp->fsp_name->base_name, smb_fname->base_name);
420 if (state->template_fname == NULL) {
424 if (!preopen_parse_fname(state->template_fname, &num,
425 &state->number_start, &state->num_digits)) {
426 TALLOC_FREE(state->template_fname);
430 if (num > state->fnum_sent) {
432 * Helpers were too slow, there's no point in reading
433 * files in helpers that we already read in the
436 state->fnum_sent = num;
439 if ((state->fnum_queue_end != 0) /* Something was started earlier */
440 && (num < (state->fnum_queue_end - state->queue_max))) {
442 * "num" is before the queue we announced. This means
443 * a new run is started.
445 state->fnum_sent = num;
448 state->fnum_queue_end = num + state->queue_max;
450 preopen_queue_run(state);
455 static int preopen_openat(struct vfs_handle_struct *handle,
456 const struct files_struct *dirfsp,
457 const struct smb_filename *smb_fname,
458 struct files_struct *fsp,
462 struct preopen_state *state;
466 DEBUG(10, ("preopen_open called on %s\n", smb_fname_str_dbg(smb_fname)));
468 state = preopen_state_get(handle);
470 return SMB_VFS_NEXT_OPENAT(handle,
478 res = SMB_VFS_NEXT_OPENAT(handle, dirfsp, smb_fname, fsp, flags, mode);
483 if ((flags & O_ACCMODE) != O_RDONLY) {
487 if (!is_in_path(smb_fname->base_name, state->preopen_names, true)) {
488 DEBUG(10, ("%s does not match the preopen:names list\n",
489 smb_fname_str_dbg(smb_fname)));
493 TALLOC_FREE(state->template_fname);
494 state->template_fname = talloc_asprintf(
496 dirfsp->fsp_name->base_name, smb_fname->base_name);
498 if (state->template_fname == NULL) {
502 if (!preopen_parse_fname(state->template_fname, &num,
503 &state->number_start, &state->num_digits)) {
504 TALLOC_FREE(state->template_fname);
508 if (num > state->fnum_sent) {
510 * Helpers were too slow, there's no point in reading
511 * files in helpers that we already read in the
514 state->fnum_sent = num;
517 if ((state->fnum_queue_end != 0) /* Something was started earlier */
518 && (num < (state->fnum_queue_end - state->queue_max))) {
520 * "num" is before the queue we announced. This means
521 * a new run is started.
523 state->fnum_sent = num;
526 state->fnum_queue_end = num + state->queue_max;
528 preopen_queue_run(state);
533 static struct vfs_fn_pointers vfs_preopen_fns = {
534 .open_fn = preopen_open,
535 .openat_fn = preopen_openat,
539 NTSTATUS vfs_preopen_init(TALLOC_CTX *ctx)
541 return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
542 "preopen", &vfs_preopen_fns);