// SPDX-License-Identifier: GPL-2.0
#ifndef NO_BCACHEFS_FS
#include "bcachefs.h"
#include "thread_with_file.h"
#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/sched/sysctl.h>
void bch2_thread_with_file_exit(struct thread_with_file *thr)
{
if (thr->task) {
kthread_stop(thr->task);
put_task_struct(thr->task);
}
}
int bch2_run_thread_with_file(struct thread_with_file *thr,
const struct file_operations *fops,
int (*fn)(void *))
{
struct file *file = NULL;
int ret, fd = -1;
unsigned fd_flags = O_CLOEXEC;
if (fops->read && fops->write)
fd_flags |= O_RDWR;
else if (fops->read)
fd_flags |= O_RDONLY;
else if (fops->write)
fd_flags |= O_WRONLY;
char name[TASK_COMM_LEN];
get_task_comm(name, current);
thr->ret = 0;
thr->task = kthread_create(fn, thr, "%s", name);
ret = PTR_ERR_OR_ZERO(thr->task);
if (ret)
return ret;
ret = get_unused_fd_flags(fd_flags);
if (ret < 0)
goto err;
fd = ret;
file = anon_inode_getfile(name, fops, thr, fd_flags);
ret = PTR_ERR_OR_ZERO(file);
if (ret)
goto err;
get_task_struct(thr->task);
wake_up_process(thr->task);
fd_install(fd, file);
return fd;
err:
if (fd >= 0)
put_unused_fd(fd);
if (thr->task)
kthread_stop(thr->task);
return ret;
}
/* stdio_redirect */
static bool stdio_redirect_has_more_input(struct stdio_redirect *stdio, size_t seen)
{
return stdio->input.buf.nr > seen || stdio->done;
}
static bool stdio_redirect_has_input(struct stdio_redirect *stdio)
{
return stdio_redirect_has_more_input(stdio, 0);
}
static bool stdio_redirect_has_output(struct stdio_redirect *stdio)
{
return stdio->output.buf.nr || stdio->done;
}
#define STDIO_REDIRECT_BUFSIZE 4096
static bool stdio_redirect_has_input_space(struct stdio_redirect *stdio)
{
return stdio->input.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
}
static bool stdio_redirect_has_output_space(struct stdio_redirect *stdio)
{
return stdio->output.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
}
static void stdio_buf_init(struct stdio_buf *buf)
{
spin_lock_init(&buf->lock);
init_waitqueue_head(&buf->wait);
darray_init(&buf->buf);
}
/* thread_with_stdio */
static void thread_with_stdio_done(struct thread_with_stdio *thr)
{
thr->thr.done = true;
thr->stdio.done = true;
wake_up(&thr->stdio.input.wait);
wake_up(&thr->stdio.output.wait);
}
static ssize_t thread_with_stdio_read(struct file *file, char __user *ubuf,
size_t len, loff_t *ppos)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
struct stdio_buf *buf = &thr->stdio.output;
size_t copied = 0, b;
int ret = 0;
if (!(file->f_flags & O_NONBLOCK)) {
ret = wait_event_interruptible(buf->wait, stdio_redirect_has_output(&thr->stdio));
if (ret)
return ret;
} else if (!stdio_redirect_has_output(&thr->stdio))
return -EAGAIN;
while (len && buf->buf.nr) {
if (fault_in_writeable(ubuf, len) == len) {
ret = -EFAULT;
break;
}
spin_lock_irq(&buf->lock);
b = min_t(size_t, len, buf->buf.nr);
if (b && !copy_to_user_nofault(ubuf, buf->buf.data, b)) {
ubuf += b;
len -= b;
copied += b;
buf->buf.nr -= b;
memmove(buf->buf.data,
buf->buf.data + b,
buf->buf.nr);
}
spin_unlock_irq(&buf->lock);
}
return copied ?: ret;
}
static int thread_with_stdio_release(struct inode *inode, struct file *file)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
thread_with_stdio_done(thr);
bch2_thread_with_file_exit(&thr->thr);
darray_exit(&thr->stdio.input.buf);
darray_exit(&thr->stdio.output.buf);
thr->ops->exit(thr);
return 0;
}
static ssize_t thread_with_stdio_write(struct file *file, const char __user *ubuf,
size_t len, loff_t *ppos)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
struct stdio_buf *buf = &thr->stdio.input;
size_t copied = 0;
ssize_t ret = 0;
while (len) {
if (thr->thr.done) {
ret = -EPIPE;
break;
}
size_t b = len - fault_in_readable(ubuf, len);
if (!b) {
ret = -EFAULT;
break;
}
spin_lock(&buf->lock);
size_t makeroom = b;
if (!buf->waiting_for_line || memchr(buf->buf.data, '\n', buf->buf.nr))
makeroom = min_t(ssize_t, makeroom,
max_t(ssize_t, STDIO_REDIRECT_BUFSIZE - buf->buf.nr,
0));
darray_make_room_gfp(&buf->buf, makeroom, GFP_NOWAIT);
b = min(len, darray_room(buf->buf));
if (b && !copy_from_user_nofault(&darray_top(buf->buf), ubuf, b)) {
buf->buf.nr += b;
ubuf += b;
len -= b;
copied += b;
}
spin_unlock(&buf->lock);
if (b) {
wake_up(&buf->wait);
} else {
if ((file->f_flags & O_NONBLOCK)) {
ret = -EAGAIN;
break;
}
ret = wait_event_interruptible(buf->wait,
stdio_redirect_has_input_space(&thr->stdio));
if (ret)
break;
}
}
return copied ?: ret;
}
static __poll_t thread_with_stdio_poll(struct file *file, struct poll_table_struct *wait)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
poll_wait(file, &thr->stdio.output.wait, wait);
poll_wait(file, &thr->stdio.input.wait, wait);
__poll_t mask = 0;
if (stdio_redirect_has_output(&thr->stdio))
mask |= EPOLLIN;
if (stdio_redirect_has_input_space(&thr->stdio))
mask |= EPOLLOUT;
if (thr->thr.done)
mask |= EPOLLHUP|EPOLLERR;
return mask;
}
static __poll_t thread_with_stdout_poll(struct file *file, struct poll_table_struct *wait)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
poll_wait(file, &thr->stdio.output.wait, wait);
__poll_t mask = 0;
if (stdio_redirect_has_output(&thr->stdio))
mask |= EPOLLIN;
if (thr->thr.done)
mask |= EPOLLHUP|EPOLLERR;
return mask;
}
static int thread_with_stdio_flush(struct file *file, fl_owner_t id)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
return thr->thr.ret;
}
static long thread_with_stdio_ioctl(struct file *file, unsigned int cmd, unsigned long p)
{
struct thread_with_stdio *thr =
container_of(file->private_data, struct thread_with_stdio, thr);
if (thr->ops->unlocked_ioctl)
return thr->ops->unlocked_ioctl(thr, cmd, p);
return -ENOTTY;
}
static const struct file_operations thread_with_stdio_fops = {
.read = thread_with_stdio_read,
.write = thread_with_stdio_write,
.poll = thread_with_stdio_poll,
.flush = thread_with_stdio_flush,
.release = thread_with_stdio_release,
.unlocked_ioctl = thread_with_stdio_ioctl,
};
static const struct file_operations thread_with_stdout_fops = {
.read = thread_with_stdio_read,
.poll = thread_with_stdout_poll,
.flush = thread_with_stdio_flush,
.release = thread_with_stdio_release,
.unlocked_ioctl = thread_with_stdio_ioctl,
};
static int thread_with_stdio_fn(void *arg)
{
struct thread_with_stdio *thr = arg;
thr->thr.ret = thr->ops->fn(thr);
thread_with_stdio_done(thr);
return 0;
}
void bch2_thread_with_stdio_init(struct thread_with_stdio *thr,
const struct thread_with_stdio_ops *ops)
{
stdio_buf_init(&thr->stdio.input);
stdio_buf_init(&thr->stdio.output);
thr->ops = ops;
}
int __bch2_run_thread_with_stdio(struct thread_with_stdio *thr)
{
return bch2_run_thread_with_file(&thr->thr, &thread_with_stdio_fops, thread_with_stdio_fn);
}
int bch2_run_thread_with_stdio(struct thread_with_stdio *thr,
const struct thread_with_stdio_ops *ops)
{
bch2_thread_with_stdio_init(thr, ops);
return __bch2_run_thread_with_stdio(thr);
}
int bch2_run_thread_with_stdout(struct thread_with_stdio *thr,
const struct thread_with_stdio_ops *ops)
{
stdio_buf_init(&thr->stdio.input);
stdio_buf_init(&thr->stdio.output);
thr->ops = ops;
return bch2_run_thread_with_file(&thr->thr, &thread_with_stdout_fops, thread_with_stdio_fn);
}
EXPORT_SYMBOL_GPL(bch2_run_thread_with_stdout);
int bch2_stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t len)
{
struct stdio_buf *buf = &stdio->input;
/*
* we're waiting on user input (or for the file descriptor to be
* closed), don't want a hung task warning:
*/
do {
wait_event_timeout(buf->wait, stdio_redirect_has_input(stdio),
sysctl_hung_task_timeout_secs * HZ / 2);
} while (!stdio_redirect_has_input(stdio));
if (stdio->done)
return -1;
spin_lock(&buf->lock);
int ret = min(len, buf->buf.nr);
buf->buf.nr -= ret;
memcpy(ubuf, buf->buf.data, ret);
memmove(buf->buf.data,
buf->buf.data + ret,
buf->buf.nr);
spin_unlock(&buf->lock);
wake_up(&buf->wait);
return ret;
}
int bch2_stdio_redirect_readline_timeout(struct stdio_redirect *stdio,
darray_char *line,
unsigned long timeout)
{
unsigned long until = jiffies + timeout, t;
struct stdio_buf *buf = &stdio->input;
size_t seen = 0;
again:
t = timeout != MAX_SCHEDULE_TIMEOUT
? max_t(long, until - jiffies, 0)
: timeout;
t = min(t, sysctl_hung_task_timeout_secs * HZ / 2);
wait_event_timeout(buf->wait, stdio_redirect_has_more_input(stdio, seen), t);
if (stdio->done)
return -1;
spin_lock(&buf->lock);
seen = buf->buf.nr;
char *n = memchr(buf->buf.data, '\n', seen);
if (!n && timeout != MAX_SCHEDULE_TIMEOUT && time_after_eq(jiffies, until)) {
spin_unlock(&buf->lock);
return -ETIME;
}
if (!n) {
buf->waiting_for_line = true;
spin_unlock(&buf->lock);
goto again;
}
size_t b = n + 1 - buf->buf.data;
if (b > line->size) {
spin_unlock(&buf->lock);
int ret = darray_resize(line, b);
if (ret)
return ret;
seen = 0;
goto again;
}
buf->buf.nr -= b;
memcpy(line->data, buf->buf.data, b);
memmove(buf->buf.data,
buf->buf.data + b,
buf->buf.nr);
line->nr = b;
buf->waiting_for_line = false;
spin_unlock(&buf->lock);
wake_up(&buf->wait);
return 0;
}
int bch2_stdio_redirect_readline(struct stdio_redirect *stdio, darray_char *line)
{
return bch2_stdio_redirect_readline_timeout(stdio, line, MAX_SCHEDULE_TIMEOUT);
}
__printf(3, 0)
static ssize_t bch2_darray_vprintf(darray_char *out, gfp_t gfp, const char *fmt, va_list args)
{
ssize_t ret;
do {
va_list args2;
size_t len;
va_copy(args2, args);
len = vsnprintf(out->data + out->nr, darray_room(*out), fmt, args2);
va_end(args2);
if (len + 1 <= darray_room(*out)) {
out->nr += len;
return len;
}
ret = darray_make_room_gfp(out, len + 1, gfp);
} while (ret == 0);
return ret;
}
ssize_t bch2_stdio_redirect_vprintf(struct stdio_redirect *stdio, bool nonblocking,
const char *fmt, va_list args)
{
struct stdio_buf *buf = &stdio->output;
unsigned long flags;
ssize_t ret;
again:
spin_lock_irqsave(&buf->lock, flags);
ret = bch2_darray_vprintf(&buf->buf, GFP_NOWAIT, fmt, args);
spin_unlock_irqrestore(&buf->lock, flags);
if (ret < 0) {
if (nonblocking)
return -EAGAIN;
ret = wait_event_interruptible(buf->wait,
stdio_redirect_has_output_space(stdio));
if (ret)
return ret;
goto again;
}
wake_up(&buf->wait);
return ret;
}
ssize_t bch2_stdio_redirect_printf(struct stdio_redirect *stdio, bool nonblocking,
const char *fmt, ...)
{
va_list args;
ssize_t ret;
va_start(args, fmt);
ret = bch2_stdio_redirect_vprintf(stdio, nonblocking, fmt, args);
va_end(args);
return ret;
}
#endif /* NO_BCACHEFS_FS */
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