2 * Simulate the Posix AIO using mmap/fork
4 * Copyright (C) Volker Lendecke 2008
5 * Copyright (C) Jeremy Allison 2010
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #include "system/filesys.h"
24 #include "system/shmem.h"
25 #include "smbd/smbd.h"
26 #include "smbd/globals.h"
27 #include "lib/async_req/async_sock.h"
28 #include "lib/util/tevent_unix.h"
29 #include "lib/util/sys_rw.h"
30 #include "lib/util/sys_rw_data.h"
31 #include "lib/msghdr.h"
33 #if !defined(HAVE_STRUCT_MSGHDR_MSG_CONTROL) && !defined(HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS)
34 # error Can not pass file descriptors
43 struct aio_fork_config {
44 bool erratic_testing_mode;
52 static int mmap_area_destructor(struct mmap_area *area)
54 munmap(discard_const(area->ptr), area->size);
58 static struct mmap_area *mmap_area_init(TALLOC_CTX *mem_ctx, size_t size)
60 struct mmap_area *result;
63 result = talloc(mem_ctx, struct mmap_area);
65 DEBUG(0, ("talloc failed\n"));
69 fd = open("/dev/zero", O_RDWR);
71 DEBUG(3, ("open(\"/dev/zero\") failed: %s\n",
76 result->ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
77 MAP_SHARED|MAP_FILE, fd, 0);
79 if (result->ptr == MAP_FAILED) {
80 DEBUG(1, ("mmap failed: %s\n", strerror(errno)));
85 talloc_set_destructor(result, mmap_area_destructor);
100 static const char *cmd_type_str(enum cmd_type cmd)
115 result = "<UNKNOWN>";
125 bool erratic_testing_mode;
133 struct aio_child_list;
136 struct aio_child *prev, *next;
137 struct aio_child_list *list;
140 struct mmap_area *map;
141 bool dont_delete; /* Marked as in use since last cleanup */
145 struct aio_child_list {
146 struct aio_child *children;
147 struct tevent_timer *cleanup_event;
150 static void free_aio_children(void **p)
155 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
158 struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1 };
160 size_t bufsize = msghdr_prep_recv_fds(NULL, NULL, 0, 1);
161 uint8_t buf[bufsize];
163 msghdr_prep_recv_fds(&msg, buf, bufsize, 1);
165 iov[0].iov_base = (void *)ptr;
166 iov[0].iov_len = nbytes;
169 n = recvmsg(fd, &msg, 0);
170 } while ((n == -1) && (errno == EINTR));
177 size_t num_fds = msghdr_extract_fds(&msg, NULL, 0);
180 msghdr_extract_fds(&msg, fds, num_fds);
185 for (i=0; i<num_fds; i++) {
199 static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd)
201 struct msghdr msg = {0};
202 size_t bufsize = msghdr_prep_fds(NULL, NULL, 0, &sendfd, 1);
203 uint8_t buf[bufsize];
207 msghdr_prep_fds(&msg, buf, bufsize, &sendfd, 1);
209 iov.iov_base = (void *)ptr;
210 iov.iov_len = nbytes;
215 sent = sendmsg(fd, &msg, 0);
216 } while ((sent == -1) && (errno == EINTR));
221 static void aio_child_cleanup(struct tevent_context *event_ctx,
222 struct tevent_timer *te,
226 struct aio_child_list *list = talloc_get_type_abort(
227 private_data, struct aio_child_list);
228 struct aio_child *child, *next;
230 TALLOC_FREE(list->cleanup_event);
232 for (child = list->children; child != NULL; child = next) {
236 DEBUG(10, ("child %d currently active\n",
241 if (child->dont_delete) {
242 DEBUG(10, ("Child %d was active since last cleanup\n",
244 child->dont_delete = false;
248 DEBUG(10, ("Child %d idle for more than 30 seconds, "
249 "deleting\n", (int)child->pid));
255 if (list->children != NULL) {
257 * Re-schedule the next cleanup round
259 list->cleanup_event = tevent_add_timer(server_event_context(), list,
260 timeval_add(&now, 30, 0),
261 aio_child_cleanup, list);
266 static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle)
268 struct aio_child_list *data = NULL;
270 if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
271 SMB_VFS_HANDLE_GET_DATA(handle, data, struct aio_child_list,
276 data = talloc_zero(NULL, struct aio_child_list);
283 * Regardless of whether the child_list had been around or not, make
284 * sure that we have a cleanup timed event. This timed event will
285 * delete itself when it finds that no children are around anymore.
288 if (data->cleanup_event == NULL) {
289 data->cleanup_event = tevent_add_timer(server_event_context(), data,
290 timeval_current_ofs(30, 0),
291 aio_child_cleanup, data);
292 if (data->cleanup_event == NULL) {
298 if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
299 SMB_VFS_HANDLE_SET_DATA(handle, data, free_aio_children,
300 struct aio_child_list, return False);
306 static void aio_child_loop(int sockfd, struct mmap_area *map)
311 struct rw_cmd cmd_struct;
312 struct rw_ret ret_struct;
314 ret = read_fd(sockfd, &cmd_struct, sizeof(cmd_struct), &fd);
315 if (ret != sizeof(cmd_struct)) {
316 DEBUG(10, ("read_fd returned %d: %s\n", (int)ret,
321 DEBUG(10, ("aio_child_loop: %s %d bytes at %d from fd %d\n",
322 cmd_type_str(cmd_struct.cmd),
323 (int)cmd_struct.n, (int)cmd_struct.offset, fd));
325 if (cmd_struct.erratic_testing_mode) {
327 * For developer testing, we want erratic behaviour for
333 * use generate_random_buffer, we just forked from a
334 * common parent state
336 generate_random_buffer(&randval, sizeof(randval));
337 msecs = randval + 20;
338 DEBUG(10, ("delaying for %u msecs\n", msecs));
342 ZERO_STRUCT(ret_struct);
344 switch (cmd_struct.cmd) {
346 ret_struct.size = sys_pread(
347 fd, discard_const(map->ptr), cmd_struct.n,
350 /* This breaks "make test" when run with aio_fork module. */
352 ret_struct.size = MAX(1, ret_struct.size * 0.9);
357 ret_struct.size = sys_pwrite(
358 fd, discard_const(map->ptr), cmd_struct.n,
362 ret_struct.size = fsync(fd);
365 ret_struct.size = -1;
369 DEBUG(10, ("aio_child_loop: syscall returned %d\n",
370 (int)ret_struct.size));
372 if (ret_struct.size == -1) {
373 ret_struct.ret_errno = errno;
377 * Close the fd before telling our parent we're done. The
378 * parent might close and re-open the file very quickly, and
379 * with system-level share modes (GPFS) we would get an
380 * unjustified SHARING_VIOLATION.
384 ret = write_data(sockfd, (char *)&ret_struct,
386 if (ret != sizeof(ret_struct)) {
387 DEBUG(10, ("could not write ret_struct: %s\n",
394 static int aio_child_destructor(struct aio_child *child)
398 SMB_ASSERT(!child->busy);
400 DEBUG(10, ("aio_child_destructor: removing child %d on fd %d\n",
401 (int)child->pid, child->sockfd));
404 * closing the sockfd makes the child not return from recvmsg() on RHEL
405 * 5.5 so instead force the child to exit by writing bad data to it
407 write(child->sockfd, &c, sizeof(c));
408 close(child->sockfd);
409 DLIST_REMOVE(child->list->children, child);
414 * We have to close all fd's in open files, we might incorrectly hold a system
415 * level share mode on a file.
418 static struct files_struct *close_fsp_fd(struct files_struct *fsp,
421 if ((fsp->fh != NULL) && (fsp->fh->fd != -1)) {
428 static int create_aio_child(struct smbd_server_connection *sconn,
429 struct aio_child_list *children,
431 struct aio_child **presult)
433 struct aio_child *result;
437 fdpair[0] = fdpair[1] = -1;
439 result = talloc_zero(children, struct aio_child);
440 if (result == NULL) {
444 if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
446 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
450 DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
452 result->map = mmap_area_init(result, map_size);
453 if (result->map == NULL) {
455 DEBUG(0, ("Could not create mmap area\n"));
459 result->pid = fork();
460 if (result->pid == -1) {
462 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
466 if (result->pid == 0) {
468 result->sockfd = fdpair[1];
469 files_forall(sconn, close_fsp_fd, NULL);
470 aio_child_loop(result->sockfd, result->map);
473 DEBUG(10, ("Child %d created with sockfd %d\n",
474 (int)result->pid, fdpair[0]));
476 result->sockfd = fdpair[0];
479 result->list = children;
480 DLIST_ADD(children->children, result);
482 talloc_set_destructor(result, aio_child_destructor);
489 if (fdpair[0] != -1) close(fdpair[0]);
490 if (fdpair[1] != -1) close(fdpair[1]);
496 static int get_idle_child(struct vfs_handle_struct *handle,
497 struct aio_child **pchild)
499 struct aio_child_list *children;
500 struct aio_child *child;
502 children = init_aio_children(handle);
503 if (children == NULL) {
507 for (child = children->children; child != NULL; child = child->next) {
516 DEBUG(10, ("no idle child found, creating new one\n"));
518 ret = create_aio_child(handle->conn->sconn, children,
521 DEBUG(10, ("create_aio_child failed: %s\n",
527 child->dont_delete = true;
534 struct aio_fork_pread_state {
535 struct aio_child *child;
540 static void aio_fork_pread_done(struct tevent_req *subreq);
542 static struct tevent_req *aio_fork_pread_send(struct vfs_handle_struct *handle,
544 struct tevent_context *ev,
545 struct files_struct *fsp,
547 size_t n, off_t offset)
549 struct tevent_req *req, *subreq;
550 struct aio_fork_pread_state *state;
554 struct aio_fork_config *config;
556 SMB_VFS_HANDLE_GET_DATA(handle, config,
557 struct aio_fork_config,
560 req = tevent_req_create(mem_ctx, &state, struct aio_fork_pread_state);
566 /* TODO: support variable buffers */
567 tevent_req_error(req, EINVAL);
568 return tevent_req_post(req, ev);
571 err = get_idle_child(handle, &state->child);
573 tevent_req_error(req, err);
574 return tevent_req_post(req, ev);
581 cmd.erratic_testing_mode = config->erratic_testing_mode;
583 DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
584 (int)state->child->pid));
587 * Not making this async. We're writing into an empty unix
588 * domain socket. This should never block.
590 written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
595 TALLOC_FREE(state->child);
597 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
598 tevent_req_error(req, err);
599 return tevent_req_post(req, ev);
602 subreq = read_packet_send(state, ev, state->child->sockfd,
603 sizeof(struct rw_ret), NULL, NULL);
604 if (tevent_req_nomem(subreq, req)) {
605 TALLOC_FREE(state->child); /* we sent sth down */
606 return tevent_req_post(req, ev);
608 tevent_req_set_callback(subreq, aio_fork_pread_done, req);
612 static void aio_fork_pread_done(struct tevent_req *subreq)
614 struct tevent_req *req = tevent_req_callback_data(
615 subreq, struct tevent_req);
616 struct aio_fork_pread_state *state = tevent_req_data(
617 req, struct aio_fork_pread_state);
621 struct rw_ret *retbuf;
623 nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
626 TALLOC_FREE(state->child);
627 tevent_req_error(req, err);
631 state->child->busy = false;
633 retbuf = (struct rw_ret *)buf;
634 state->ret = retbuf->size;
635 state->err = retbuf->ret_errno;
636 tevent_req_done(req);
639 static ssize_t aio_fork_pread_recv(struct tevent_req *req, int *err)
641 struct aio_fork_pread_state *state = tevent_req_data(
642 req, struct aio_fork_pread_state);
644 if (tevent_req_is_unix_error(req, err)) {
647 if (state->ret == -1) {
653 struct aio_fork_pwrite_state {
654 struct aio_child *child;
659 static void aio_fork_pwrite_done(struct tevent_req *subreq);
661 static struct tevent_req *aio_fork_pwrite_send(
662 struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
663 struct tevent_context *ev, struct files_struct *fsp,
664 const void *data, size_t n, off_t offset)
666 struct tevent_req *req, *subreq;
667 struct aio_fork_pwrite_state *state;
671 struct aio_fork_config *config;
672 SMB_VFS_HANDLE_GET_DATA(handle, config,
673 struct aio_fork_config,
676 req = tevent_req_create(mem_ctx, &state, struct aio_fork_pwrite_state);
682 /* TODO: support variable buffers */
683 tevent_req_error(req, EINVAL);
684 return tevent_req_post(req, ev);
687 err = get_idle_child(handle, &state->child);
689 tevent_req_error(req, err);
690 return tevent_req_post(req, ev);
697 cmd.erratic_testing_mode = config->erratic_testing_mode;
699 DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
700 (int)state->child->pid));
703 * Not making this async. We're writing into an empty unix
704 * domain socket. This should never block.
706 written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
711 TALLOC_FREE(state->child);
713 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
714 tevent_req_error(req, err);
715 return tevent_req_post(req, ev);
718 subreq = read_packet_send(state, ev, state->child->sockfd,
719 sizeof(struct rw_ret), NULL, NULL);
720 if (tevent_req_nomem(subreq, req)) {
721 TALLOC_FREE(state->child); /* we sent sth down */
722 return tevent_req_post(req, ev);
724 tevent_req_set_callback(subreq, aio_fork_pwrite_done, req);
728 static void aio_fork_pwrite_done(struct tevent_req *subreq)
730 struct tevent_req *req = tevent_req_callback_data(
731 subreq, struct tevent_req);
732 struct aio_fork_pwrite_state *state = tevent_req_data(
733 req, struct aio_fork_pwrite_state);
737 struct rw_ret *retbuf;
739 nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
742 TALLOC_FREE(state->child);
743 tevent_req_error(req, err);
747 state->child->busy = false;
749 retbuf = (struct rw_ret *)buf;
750 state->ret = retbuf->size;
751 state->err = retbuf->ret_errno;
752 tevent_req_done(req);
755 static ssize_t aio_fork_pwrite_recv(struct tevent_req *req, int *err)
757 struct aio_fork_pwrite_state *state = tevent_req_data(
758 req, struct aio_fork_pwrite_state);
760 if (tevent_req_is_unix_error(req, err)) {
763 if (state->ret == -1) {
769 struct aio_fork_fsync_state {
770 struct aio_child *child;
775 static void aio_fork_fsync_done(struct tevent_req *subreq);
777 static struct tevent_req *aio_fork_fsync_send(
778 struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
779 struct tevent_context *ev, struct files_struct *fsp)
781 struct tevent_req *req, *subreq;
782 struct aio_fork_fsync_state *state;
786 struct aio_fork_config *config;
788 SMB_VFS_HANDLE_GET_DATA(handle, config,
789 struct aio_fork_config,
792 req = tevent_req_create(mem_ctx, &state, struct aio_fork_fsync_state);
797 err = get_idle_child(handle, &state->child);
799 tevent_req_error(req, err);
800 return tevent_req_post(req, ev);
805 cmd.erratic_testing_mode = config->erratic_testing_mode;
807 DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
808 (int)state->child->pid));
811 * Not making this async. We're writing into an empty unix
812 * domain socket. This should never block.
814 written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
819 TALLOC_FREE(state->child);
821 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
822 tevent_req_error(req, err);
823 return tevent_req_post(req, ev);
826 subreq = read_packet_send(state, ev, state->child->sockfd,
827 sizeof(struct rw_ret), NULL, NULL);
828 if (tevent_req_nomem(subreq, req)) {
829 TALLOC_FREE(state->child); /* we sent sth down */
830 return tevent_req_post(req, ev);
832 tevent_req_set_callback(subreq, aio_fork_fsync_done, req);
836 static void aio_fork_fsync_done(struct tevent_req *subreq)
838 struct tevent_req *req = tevent_req_callback_data(
839 subreq, struct tevent_req);
840 struct aio_fork_fsync_state *state = tevent_req_data(
841 req, struct aio_fork_fsync_state);
845 struct rw_ret *retbuf;
847 nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
850 TALLOC_FREE(state->child);
851 tevent_req_error(req, err);
855 state->child->busy = false;
857 retbuf = (struct rw_ret *)buf;
858 state->ret = retbuf->size;
859 state->err = retbuf->ret_errno;
860 tevent_req_done(req);
863 static int aio_fork_fsync_recv(struct tevent_req *req, int *err)
865 struct aio_fork_fsync_state *state = tevent_req_data(
866 req, struct aio_fork_fsync_state);
868 if (tevent_req_is_unix_error(req, err)) {
871 if (state->ret == -1) {
877 static int aio_fork_connect(vfs_handle_struct *handle, const char *service,
881 struct aio_fork_config *config;
882 ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
888 config = talloc_zero(handle->conn, struct aio_fork_config);
890 SMB_VFS_NEXT_DISCONNECT(handle);
891 DEBUG(0, ("talloc_zero() failed\n"));
895 config->erratic_testing_mode = lp_parm_bool(SNUM(handle->conn), "vfs_aio_fork",
896 "erratic_testing_mode", false);
898 SMB_VFS_HANDLE_SET_DATA(handle, config,
899 NULL, struct aio_fork_config,
905 static struct vfs_fn_pointers vfs_aio_fork_fns = {
906 .connect_fn = aio_fork_connect,
907 .pread_send_fn = aio_fork_pread_send,
908 .pread_recv_fn = aio_fork_pread_recv,
909 .pwrite_send_fn = aio_fork_pwrite_send,
910 .pwrite_recv_fn = aio_fork_pwrite_recv,
911 .fsync_send_fn = aio_fork_fsync_send,
912 .fsync_recv_fn = aio_fork_fsync_recv,
915 NTSTATUS vfs_aio_fork_init(void);
916 NTSTATUS vfs_aio_fork_init(void)
918 return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
919 "aio_fork", &vfs_aio_fork_fns);