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Diffstat (limited to 'fs/pipe.c')
-rw-r--r--fs/pipe.c147
1 files changed, 106 insertions, 41 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index d79872eba09a..da42f7db50de 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -26,9 +26,14 @@
/*
* The max size that a non-root user is allowed to grow the pipe. Can
- * be set by root in /proc/sys/fs/pipe-max-pages
+ * be set by root in /proc/sys/fs/pipe-max-size
*/
-unsigned int pipe_max_pages = PIPE_DEF_BUFFERS * 16;
+unsigned int pipe_max_size = 1048576;
+
+/*
+ * Minimum pipe size, as required by POSIX
+ */
+unsigned int pipe_min_size = PAGE_SIZE;
/*
* We use a start+len construction, which provides full use of the
@@ -230,6 +235,7 @@ void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
return kmap(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_map);
/**
* generic_pipe_buf_unmap - unmap a previously mapped pipe buffer
@@ -249,6 +255,7 @@ void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
} else
kunmap(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_unmap);
/**
* generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer
@@ -279,6 +286,7 @@ int generic_pipe_buf_steal(struct pipe_inode_info *pipe,
return 1;
}
+EXPORT_SYMBOL(generic_pipe_buf_steal);
/**
* generic_pipe_buf_get - get a reference to a &struct pipe_buffer
@@ -294,6 +302,7 @@ void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
{
page_cache_get(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_get);
/**
* generic_pipe_buf_confirm - verify contents of the pipe buffer
@@ -309,6 +318,7 @@ int generic_pipe_buf_confirm(struct pipe_inode_info *info,
{
return 0;
}
+EXPORT_SYMBOL(generic_pipe_buf_confirm);
/**
* generic_pipe_buf_release - put a reference to a &struct pipe_buffer
@@ -323,6 +333,7 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
{
page_cache_release(buf->page);
}
+EXPORT_SYMBOL(generic_pipe_buf_release);
static const struct pipe_buf_operations anon_pipe_buf_ops = {
.can_merge = 1,
@@ -371,7 +382,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
error = ops->confirm(pipe, buf);
if (error) {
if (!ret)
- error = ret;
+ ret = error;
break;
}
@@ -430,7 +441,7 @@ redo:
break;
}
if (do_wakeup) {
- wake_up_interruptible_sync(&pipe->wait);
+ wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
pipe_wait(pipe);
@@ -439,7 +450,7 @@ redo:
/* Signal writers asynchronously that there is more room. */
if (do_wakeup) {
- wake_up_interruptible_sync(&pipe->wait);
+ wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
if (ret > 0)
@@ -601,7 +612,7 @@ redo2:
break;
}
if (do_wakeup) {
- wake_up_interruptible_sync(&pipe->wait);
+ wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
do_wakeup = 0;
}
@@ -612,7 +623,7 @@ redo2:
out:
mutex_unlock(&inode->i_mutex);
if (do_wakeup) {
- wake_up_interruptible_sync(&pipe->wait);
+ wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
}
if (ret > 0)
@@ -704,7 +715,7 @@ pipe_release(struct inode *inode, int decr, int decw)
if (!pipe->readers && !pipe->writers) {
free_pipe_info(inode);
} else {
- wake_up_interruptible_sync(&pipe->wait);
+ wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM | POLLERR | POLLHUP);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
@@ -943,6 +954,8 @@ static struct inode * get_pipe_inode(void)
if (!inode)
goto fail_inode;
+ inode->i_ino = get_next_ino();
+
pipe = alloc_pipe_info(inode);
if (!pipe)
goto fail_iput;
@@ -986,12 +999,11 @@ struct file *create_write_pipe(int flags)
goto err;
err = -ENOMEM;
- path.dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name);
+ path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name);
if (!path.dentry)
goto err_inode;
path.mnt = mntget(pipe_mnt);
- path.dentry->d_op = &pipefs_dentry_operations;
d_instantiate(path.dentry, inode);
err = -ENFILE;
@@ -1112,26 +1124,20 @@ SYSCALL_DEFINE1(pipe, int __user *, fildes)
* Allocate a new array of pipe buffers and copy the info over. Returns the
* pipe size if successful, or return -ERROR on error.
*/
-static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
+static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
{
struct pipe_buffer *bufs;
/*
- * Must be a power-of-2 currently
- */
- if (!is_power_of_2(arg))
- return -EINVAL;
-
- /*
* We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't
* expect a lot of shrink+grow operations, just free and allocate
* again like we would do for growing. If the pipe currently
* contains more buffers than arg, then return busy.
*/
- if (arg < pipe->nrbufs)
+ if (nr_pages < pipe->nrbufs)
return -EBUSY;
- bufs = kcalloc(arg, sizeof(struct pipe_buffer), GFP_KERNEL);
+ bufs = kcalloc(nr_pages, sizeof(struct pipe_buffer), GFP_KERNEL);
if (unlikely(!bufs))
return -ENOMEM;
@@ -1140,20 +1146,68 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
* and adjust the indexes.
*/
if (pipe->nrbufs) {
- const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1);
- const unsigned int head = pipe->nrbufs - tail;
+ unsigned int tail;
+ unsigned int head;
+ tail = pipe->curbuf + pipe->nrbufs;
+ if (tail < pipe->buffers)
+ tail = 0;
+ else
+ tail &= (pipe->buffers - 1);
+
+ head = pipe->nrbufs - tail;
if (head)
memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer));
if (tail)
- memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer));
+ memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer));
}
pipe->curbuf = 0;
kfree(pipe->bufs);
pipe->bufs = bufs;
- pipe->buffers = arg;
- return arg;
+ pipe->buffers = nr_pages;
+ return nr_pages * PAGE_SIZE;
+}
+
+/*
+ * Currently we rely on the pipe array holding a power-of-2 number
+ * of pages.
+ */
+static inline unsigned int round_pipe_size(unsigned int size)
+{
+ unsigned long nr_pages;
+
+ nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ return roundup_pow_of_two(nr_pages) << PAGE_SHIFT;
+}
+
+/*
+ * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax
+ * will return an error.
+ */
+int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
+ size_t *lenp, loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_dointvec_minmax(table, write, buf, lenp, ppos);
+ if (ret < 0 || !write)
+ return ret;
+
+ pipe_max_size = round_pipe_size(pipe_max_size);
+ return ret;
+}
+
+/*
+ * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
+ * location, so checking ->i_pipe is not enough to verify that this is a
+ * pipe.
+ */
+struct pipe_inode_info *get_pipe_info(struct file *file)
+{
+ struct inode *i = file->f_path.dentry->d_inode;
+
+ return S_ISFIFO(i->i_mode) ? i->i_pipe : NULL;
}
long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
@@ -1161,52 +1215,63 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
struct pipe_inode_info *pipe;
long ret;
- pipe = file->f_path.dentry->d_inode->i_pipe;
+ pipe = get_pipe_info(file);
if (!pipe)
return -EBADF;
mutex_lock(&pipe->inode->i_mutex);
switch (cmd) {
- case F_SETPIPE_SZ:
- if (!capable(CAP_SYS_ADMIN) && arg > pipe_max_pages)
- return -EINVAL;
- /*
- * The pipe needs to be at least 2 pages large to
- * guarantee POSIX behaviour.
- */
- if (arg < 2)
- return -EINVAL;
- ret = pipe_set_size(pipe, arg);
+ case F_SETPIPE_SZ: {
+ unsigned int size, nr_pages;
+
+ size = round_pipe_size(arg);
+ nr_pages = size >> PAGE_SHIFT;
+
+ ret = -EINVAL;
+ if (!nr_pages)
+ goto out;
+
+ if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
+ ret = -EPERM;
+ goto out;
+ }
+ ret = pipe_set_size(pipe, nr_pages);
break;
+ }
case F_GETPIPE_SZ:
- ret = pipe->buffers;
+ ret = pipe->buffers * PAGE_SIZE;
break;
default:
ret = -EINVAL;
break;
}
+out:
mutex_unlock(&pipe->inode->i_mutex);
return ret;
}
+static const struct super_operations pipefs_ops = {
+ .destroy_inode = free_inode_nonrcu,
+};
+
/*
* pipefs should _never_ be mounted by userland - too much of security hassle,
* no real gain from having the whole whorehouse mounted. So we don't need
* any operations on the root directory. However, we need a non-trivial
* d_name - pipe: will go nicely and kill the special-casing in procfs.
*/
-static int pipefs_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data,
- struct vfsmount *mnt)
+static struct dentry *pipefs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
{
- return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC, mnt);
+ return mount_pseudo(fs_type, "pipe:", &pipefs_ops,
+ &pipefs_dentry_operations, PIPEFS_MAGIC);
}
static struct file_system_type pipe_fs_type = {
.name = "pipefs",
- .get_sb = pipefs_get_sb,
+ .mount = pipefs_mount,
.kill_sb = kill_anon_super,
};
generated by cgit v1.2.3 (git 2.39.0) at 2025-12-15 22:30:27 +0300