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|
/*
* Simulate the Posix AIO using mmap/fork
*
* Copyright (C) Volker Lendecke 2008
*
* 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"
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);
}
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);
#ifdef ENABLE_BUILD_FARM_HACKS
ret_struct.size = MAX(1, ret_struct.size * 0.9);
#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;
DEBUG(10, ("handle_aio_completion called with flags=%d\n", flags));
if ((flags & EVENT_FD_READ) == 0) {
return;
}
if (!NT_STATUS_IS_OK(read_data(child->sockfd,
(char *)&child->retval,
sizeof(child->retval)))) {
DEBUG(0, ("aio child %d died\n", (int)child->pid));
child->retval.size = -1;
child->retval.ret_errno = EIO;
}
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);
}
smbd_aio_complete_aio_ex(aio_ex);
}
static int aio_child_destructor(struct aio_child *child)
{
SMB_ASSERT((child->aiocb == NULL) || child->cancelled);
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 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(close_fsp_fd, NULL);
aio_child_loop(result->sockfd, result->map);
}
DEBUG(10, ("Child %d created\n", result->pid));
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(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 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,
};
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);
}
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