/* * Simulate the Posix AIO using mmap/fork * * Copyright (C) Volker Lendecke 2008 * Copyright (C) Jeremy Allison 2010 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" #include "system/filesys.h" #include "system/shmem.h" #include "smbd/smbd.h" struct mmap_area { size_t size; volatile void *ptr; }; static int mmap_area_destructor(struct mmap_area *area) { munmap((void *)area->ptr, area->size); return 0; } static struct mmap_area *mmap_area_init(TALLOC_CTX *mem_ctx, size_t size) { struct mmap_area *result; int fd; result = talloc(mem_ctx, struct mmap_area); if (result == NULL) { DEBUG(0, ("talloc failed\n")); goto fail; } fd = open("/dev/zero", O_RDWR); if (fd == -1) { DEBUG(3, ("open(\"/dev/zero\") failed: %s\n", strerror(errno))); goto fail; } result->ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FILE, fd, 0); if (result->ptr == MAP_FAILED) { DEBUG(1, ("mmap failed: %s\n", strerror(errno))); goto fail; } close(fd); result->size = size; talloc_set_destructor(result, mmap_area_destructor); return result; fail: TALLOC_FREE(result); return NULL; } struct rw_cmd { size_t n; SMB_OFF_T offset; bool read_cmd; }; struct rw_ret { ssize_t size; int ret_errno; }; struct aio_child_list; struct aio_child { struct aio_child *prev, *next; struct aio_child_list *list; SMB_STRUCT_AIOCB *aiocb; pid_t pid; int sockfd; struct fd_event *sock_event; struct rw_ret retval; struct mmap_area *map; /* ==NULL means write request */ bool dont_delete; /* Marked as in use since last cleanup */ bool cancelled; bool read_cmd; }; struct aio_child_list { struct aio_child *children; struct timed_event *cleanup_event; }; static void free_aio_children(void **p) { TALLOC_FREE(*p); } static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd) { struct msghdr msg; struct iovec iov[1]; ssize_t n; #ifndef HAVE_MSGHDR_MSG_CONTROL int newfd; #endif #ifdef HAVE_MSGHDR_MSG_CONTROL union { struct cmsghdr cm; char control[CMSG_SPACE(sizeof(int))]; } control_un; struct cmsghdr *cmptr; msg.msg_control = control_un.control; msg.msg_controllen = sizeof(control_un.control); #else #if HAVE_MSGHDR_MSG_ACCTRIGHTS msg.msg_accrights = (caddr_t) &newfd; msg.msg_accrightslen = sizeof(int); #else #error Can not pass file descriptors #endif #endif msg.msg_name = NULL; msg.msg_namelen = 0; iov[0].iov_base = (void *)ptr; iov[0].iov_len = nbytes; msg.msg_iov = iov; msg.msg_iovlen = 1; if ( (n = recvmsg(fd, &msg, 0)) <= 0) { return(n); } #ifdef HAVE_MSGHDR_MSG_CONTROL if ((cmptr = CMSG_FIRSTHDR(&msg)) != NULL && cmptr->cmsg_len == CMSG_LEN(sizeof(int))) { if (cmptr->cmsg_level != SOL_SOCKET) { DEBUG(10, ("control level != SOL_SOCKET")); errno = EINVAL; return -1; } if (cmptr->cmsg_type != SCM_RIGHTS) { DEBUG(10, ("control type != SCM_RIGHTS")); errno = EINVAL; return -1; } *recvfd = *((int *) CMSG_DATA(cmptr)); } else { *recvfd = -1; /* descriptor was not passed */ } #else if (msg.msg_accrightslen == sizeof(int)) { *recvfd = newfd; } else { *recvfd = -1; /* descriptor was not passed */ } #endif return(n); } static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd) { struct msghdr msg; struct iovec iov[1]; #ifdef HAVE_MSGHDR_MSG_CONTROL union { struct cmsghdr cm; char control[CMSG_SPACE(sizeof(int))]; } control_un; struct cmsghdr *cmptr; ZERO_STRUCT(msg); ZERO_STRUCT(control_un); msg.msg_control = control_un.control; msg.msg_controllen = sizeof(control_un.control); cmptr = CMSG_FIRSTHDR(&msg); cmptr->cmsg_len = CMSG_LEN(sizeof(int)); cmptr->cmsg_level = SOL_SOCKET; cmptr->cmsg_type = SCM_RIGHTS; *((int *) CMSG_DATA(cmptr)) = sendfd; #else ZERO_STRUCT(msg); msg.msg_accrights = (caddr_t) &sendfd; msg.msg_accrightslen = sizeof(int); #endif msg.msg_name = NULL; msg.msg_namelen = 0; ZERO_STRUCT(iov); iov[0].iov_base = (void *)ptr; iov[0].iov_len = nbytes; msg.msg_iov = iov; msg.msg_iovlen = 1; return (sendmsg(fd, &msg, 0)); } static void aio_child_cleanup(struct event_context *event_ctx, struct timed_event *te, struct timeval now, void *private_data) { struct aio_child_list *list = talloc_get_type_abort( private_data, struct aio_child_list); struct aio_child *child, *next; TALLOC_FREE(list->cleanup_event); for (child = list->children; child != NULL; child = next) { next = child->next; if (child->aiocb != NULL) { DEBUG(10, ("child %d currently active\n", (int)child->pid)); continue; } if (child->dont_delete) { DEBUG(10, ("Child %d was active since last cleanup\n", (int)child->pid)); child->dont_delete = false; continue; } DEBUG(10, ("Child %d idle for more than 30 seconds, " "deleting\n", (int)child->pid)); TALLOC_FREE(child); child = next; } if (list->children != NULL) { /* * Re-schedule the next cleanup round */ list->cleanup_event = event_add_timed(smbd_event_context(), list, timeval_add(&now, 30, 0), aio_child_cleanup, list); } } static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle) { struct aio_child_list *data = NULL; if (SMB_VFS_HANDLE_TEST_DATA(handle)) { SMB_VFS_HANDLE_GET_DATA(handle, data, struct aio_child_list, return NULL); } if (data == NULL) { data = TALLOC_ZERO_P(NULL, struct aio_child_list); if (data == NULL) { return NULL; } } /* * Regardless of whether the child_list had been around or not, make * sure that we have a cleanup timed event. This timed event will * delete itself when it finds that no children are around anymore. */ if (data->cleanup_event == NULL) { data->cleanup_event = event_add_timed(smbd_event_context(), data, timeval_current_ofs(30, 0), aio_child_cleanup, data); if (data->cleanup_event == NULL) { TALLOC_FREE(data); return NULL; } } if (!SMB_VFS_HANDLE_TEST_DATA(handle)) { SMB_VFS_HANDLE_SET_DATA(handle, data, free_aio_children, struct aio_child_list, return False); } return data; } static void aio_child_loop(int sockfd, struct mmap_area *map) { while (true) { int fd = -1; ssize_t ret; struct rw_cmd cmd_struct; struct rw_ret ret_struct; ret = read_fd(sockfd, &cmd_struct, sizeof(cmd_struct), &fd); if (ret != sizeof(cmd_struct)) { DEBUG(10, ("read_fd returned %d: %s\n", (int)ret, strerror(errno))); exit(1); } DEBUG(10, ("aio_child_loop: %s %d bytes at %d from fd %d\n", cmd_struct.read_cmd ? "read" : "write", (int)cmd_struct.n, (int)cmd_struct.offset, fd)); #ifdef ENABLE_BUILD_FARM_HACKS { /* * In the build farm, we want erratic behaviour for * async I/O times */ uint8_t randval; unsigned msecs; /* * use generate_random_buffer, we just forked from a * common parent state */ generate_random_buffer(&randval, sizeof(randval)); msecs = randval + 20; DEBUG(10, ("delaying for %u msecs\n", msecs)); smb_msleep(msecs); } #endif ZERO_STRUCT(ret_struct); if (cmd_struct.read_cmd) { ret_struct.size = sys_pread( fd, (void *)map->ptr, cmd_struct.n, cmd_struct.offset); #if 0 /* This breaks "make test" when run with aio_fork module. */ #ifdef ENABLE_BUILD_FARM_HACKS ret_struct.size = MAX(1, ret_struct.size * 0.9); #endif #endif } else { ret_struct.size = sys_pwrite( fd, (void *)map->ptr, cmd_struct.n, cmd_struct.offset); } DEBUG(10, ("aio_child_loop: syscall returned %d\n", (int)ret_struct.size)); if (ret_struct.size == -1) { ret_struct.ret_errno = errno; } /* * Close the fd before telling our parent we're done. The * parent might close and re-open the file very quickly, and * with system-level share modes (GPFS) we would get an * unjustified SHARING_VIOLATION. */ close(fd); ret = write_data(sockfd, (char *)&ret_struct, sizeof(ret_struct)); if (ret != sizeof(ret_struct)) { DEBUG(10, ("could not write ret_struct: %s\n", strerror(errno))); exit(2); } } } static void handle_aio_completion(struct event_context *event_ctx, struct fd_event *event, uint16 flags, void *p) { struct aio_extra *aio_ex = NULL; struct aio_child *child = (struct aio_child *)p; NTSTATUS status; DEBUG(10, ("handle_aio_completion called with flags=%d\n", flags)); if ((flags & EVENT_FD_READ) == 0) { return; } status = read_data(child->sockfd, (char *)&child->retval, sizeof(child->retval)); if (!NT_STATUS_IS_OK(status)) { DEBUG(1, ("aio child %d died: %s\n", (int)child->pid, nt_errstr(status))); child->retval.size = -1; child->retval.ret_errno = EIO; } if (child->aiocb == NULL) { DEBUG(1, ("Inactive child died\n")); TALLOC_FREE(child); return; } if (child->cancelled) { child->aiocb = NULL; child->cancelled = false; return; } if (child->read_cmd && (child->retval.size > 0)) { SMB_ASSERT(child->retval.size <= child->aiocb->aio_nbytes); memcpy((void *)child->aiocb->aio_buf, (void *)child->map->ptr, child->retval.size); } aio_ex = (struct aio_extra *)child->aiocb->aio_sigevent.sigev_value.sival_ptr; smbd_aio_complete_aio_ex(aio_ex); } static int aio_child_destructor(struct aio_child *child) { char c=0; SMB_ASSERT((child->aiocb == NULL) || child->cancelled); DEBUG(10, ("aio_child_destructor: removing child %d on fd %d\n", child->pid, child->sockfd)); /* * closing the sockfd makes the child not return from recvmsg() on RHEL * 5.5 so instead force the child to exit by writing bad data to it */ write(child->sockfd, &c, sizeof(c)); close(child->sockfd); DLIST_REMOVE(child->list->children, child); return 0; } /* * We have to close all fd's in open files, we might incorrectly hold a system * level share mode on a file. */ static struct files_struct *close_fsp_fd(struct files_struct *fsp, void *private_data) { if ((fsp->fh != NULL) && (fsp->fh->fd != -1)) { close(fsp->fh->fd); fsp->fh->fd = -1; } return NULL; } static NTSTATUS create_aio_child(struct smbd_server_connection *sconn, struct aio_child_list *children, size_t map_size, struct aio_child **presult) { struct aio_child *result; int fdpair[2]; NTSTATUS status; fdpair[0] = fdpair[1] = -1; result = TALLOC_ZERO_P(children, struct aio_child); NT_STATUS_HAVE_NO_MEMORY(result); if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) { status = map_nt_error_from_unix(errno); DEBUG(10, ("socketpair() failed: %s\n", strerror(errno))); goto fail; } DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1])); result->map = mmap_area_init(result, map_size); if (result->map == NULL) { status = map_nt_error_from_unix(errno); DEBUG(0, ("Could not create mmap area\n")); goto fail; } result->pid = sys_fork(); if (result->pid == -1) { status = map_nt_error_from_unix(errno); DEBUG(0, ("fork failed: %s\n", strerror(errno))); goto fail; } if (result->pid == 0) { close(fdpair[0]); result->sockfd = fdpair[1]; files_forall(sconn, close_fsp_fd, NULL); aio_child_loop(result->sockfd, result->map); } DEBUG(10, ("Child %d created with sockfd %d\n", result->pid, fdpair[0])); result->sockfd = fdpair[0]; close(fdpair[1]); result->sock_event = event_add_fd(smbd_event_context(), result, result->sockfd, EVENT_FD_READ, handle_aio_completion, result); if (result->sock_event == NULL) { status = NT_STATUS_NO_MEMORY; DEBUG(0, ("event_add_fd failed\n")); goto fail; } result->list = children; DLIST_ADD(children->children, result); talloc_set_destructor(result, aio_child_destructor); *presult = result; return NT_STATUS_OK; fail: if (fdpair[0] != -1) close(fdpair[0]); if (fdpair[1] != -1) close(fdpair[1]); TALLOC_FREE(result); return status; } static NTSTATUS get_idle_child(struct vfs_handle_struct *handle, struct aio_child **pchild) { struct aio_child_list *children; struct aio_child *child; NTSTATUS status; children = init_aio_children(handle); if (children == NULL) { return NT_STATUS_NO_MEMORY; } for (child = children->children; child != NULL; child = child->next) { if (child->aiocb == NULL) { /* idle */ break; } } if (child == NULL) { DEBUG(10, ("no idle child found, creating new one\n")); status = create_aio_child(handle->conn->sconn, children, 128*1024, &child); if (!NT_STATUS_IS_OK(status)) { DEBUG(10, ("create_aio_child failed: %s\n", nt_errstr(status))); return status; } } child->dont_delete = true; *pchild = child; return NT_STATUS_OK; } static int aio_fork_read(struct vfs_handle_struct *handle, struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb) { struct aio_child *child; struct rw_cmd cmd; ssize_t ret; NTSTATUS status; if (aiocb->aio_nbytes > 128*1024) { /* TODO: support variable buffers */ errno = EINVAL; return -1; } status = get_idle_child(handle, &child); if (!NT_STATUS_IS_OK(status)) { DEBUG(10, ("Could not get an idle child\n")); return -1; } child->read_cmd = true; child->aiocb = aiocb; child->retval.ret_errno = EINPROGRESS; ZERO_STRUCT(cmd); cmd.n = aiocb->aio_nbytes; cmd.offset = aiocb->aio_offset; cmd.read_cmd = child->read_cmd; DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd, (int)child->pid)); ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd); if (ret == -1) { DEBUG(10, ("write_fd failed: %s\n", strerror(errno))); return -1; } return 0; } static int aio_fork_write(struct vfs_handle_struct *handle, struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb) { struct aio_child *child; struct rw_cmd cmd; ssize_t ret; NTSTATUS status; if (aiocb->aio_nbytes > 128*1024) { /* TODO: support variable buffers */ errno = EINVAL; return -1; } status = get_idle_child(handle, &child); if (!NT_STATUS_IS_OK(status)) { DEBUG(10, ("Could not get an idle child\n")); return -1; } child->read_cmd = false; child->aiocb = aiocb; child->retval.ret_errno = EINPROGRESS; memcpy((void *)child->map->ptr, (void *)aiocb->aio_buf, aiocb->aio_nbytes); ZERO_STRUCT(cmd); cmd.n = aiocb->aio_nbytes; cmd.offset = aiocb->aio_offset; cmd.read_cmd = child->read_cmd; DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd, (int)child->pid)); ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd); if (ret == -1) { DEBUG(10, ("write_fd failed: %s\n", strerror(errno))); return -1; } return 0; } static struct aio_child *aio_fork_find_child(struct vfs_handle_struct *handle, SMB_STRUCT_AIOCB *aiocb) { struct aio_child_list *children; struct aio_child *child; children = init_aio_children(handle); if (children == NULL) { return NULL; } for (child = children->children; child != NULL; child = child->next) { if (child->aiocb == aiocb) { return child; } } return NULL; } static ssize_t aio_fork_return_fn(struct vfs_handle_struct *handle, struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb) { struct aio_child *child = aio_fork_find_child(handle, aiocb); if (child == NULL) { errno = EINVAL; DEBUG(0, ("returning EINVAL\n")); return -1; } child->aiocb = NULL; if (child->retval.size == -1) { errno = child->retval.ret_errno; } return child->retval.size; } static int aio_fork_cancel(struct vfs_handle_struct *handle, struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb) { struct aio_child_list *children; struct aio_child *child; children = init_aio_children(handle); if (children == NULL) { errno = EINVAL; return -1; } for (child = children->children; child != NULL; child = child->next) { if (child->aiocb == NULL) { continue; } if (child->aiocb->aio_fildes != fsp->fh->fd) { continue; } if ((aiocb != NULL) && (child->aiocb != aiocb)) { continue; } /* * We let the child do its job, but we discard the result when * it's finished. */ child->cancelled = true; } return AIO_CANCELED; } static int aio_fork_error_fn(struct vfs_handle_struct *handle, struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb) { struct aio_child *child = aio_fork_find_child(handle, aiocb); if (child == NULL) { errno = EINVAL; return -1; } return child->retval.ret_errno; } static void aio_fork_suspend_timed_out(struct tevent_context *event_ctx, struct tevent_timer *te, struct timeval now, void *private_data) { bool *timed_out = (bool *)private_data; /* Remove this timed event handler. */ TALLOC_FREE(te); *timed_out = true; } static int aio_fork_suspend(struct vfs_handle_struct *handle, struct files_struct *fsp, const SMB_STRUCT_AIOCB * const aiocb_array[], int n, const struct timespec *timeout) { struct aio_child_list *children = NULL; TALLOC_CTX *frame = talloc_stackframe(); struct event_context *ev = NULL; int i; int ret = -1; bool timed_out = false; children = init_aio_children(handle); if (children == NULL) { errno = EINVAL; goto out; } /* This is a blocking call, and has to use a sub-event loop. */ ev = event_context_init(frame); if (ev == NULL) { errno = ENOMEM; goto out; } if (timeout) { struct timeval tv = convert_timespec_to_timeval(*timeout); struct tevent_timer *te = tevent_add_timer(ev, frame, timeval_current_ofs(tv.tv_sec, tv.tv_usec), aio_fork_suspend_timed_out, &timed_out); if (!te) { errno = ENOMEM; goto out; } } for (i = 0; i < n; i++) { struct aio_child *child = NULL; const SMB_STRUCT_AIOCB *aiocb = aiocb_array[i]; if (!aiocb) { continue; } /* * We're going to cheat here. We know that smbd/aio.c * only calls this when it's waiting for every single * outstanding call to finish on a close, so just wait * individually for each IO to complete. We don't care * what order they finish - only that they all do. JRA. */ for (child = children->children; child != NULL; child = child->next) { if (child->aiocb == NULL) { continue; } if (child->aiocb->aio_fildes != fsp->fh->fd) { continue; } if (child->aiocb != aiocb) { continue; } if (child->aiocb->aio_sigevent.sigev_value.sival_ptr == NULL) { continue; } /* We're never using this event on the * main event context again... */ TALLOC_FREE(child->sock_event); child->sock_event = event_add_fd(ev, child, child->sockfd, EVENT_FD_READ, handle_aio_completion, child); while (1) { if (tevent_loop_once(ev) == -1) { goto out; } if (timed_out) { errno = EAGAIN; goto out; } /* We set child->aiocb to NULL in our hooked * AIO_RETURN(). */ if (child->aiocb == NULL) { break; } } } } ret = 0; out: TALLOC_FREE(frame); return ret; } static struct vfs_fn_pointers vfs_aio_fork_fns = { .aio_read = aio_fork_read, .aio_write = aio_fork_write, .aio_return_fn = aio_fork_return_fn, .aio_cancel = aio_fork_cancel, .aio_error_fn = aio_fork_error_fn, .aio_suspend = aio_fork_suspend, }; NTSTATUS vfs_aio_fork_init(void); NTSTATUS vfs_aio_fork_init(void) { return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "aio_fork", &vfs_aio_fork_fns); }