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-rw-r--r--fs/pipe.c835
1 files changed, 835 insertions, 0 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
new file mode 100644
index 000000000000..25aa09f9d09d
--- /dev/null
+++ b/fs/pipe.c
@@ -0,0 +1,835 @@
+/*
+ * linux/fs/pipe.c
+ *
+ * Copyright (C) 1991, 1992, 1999 Linus Torvalds
+ */
+
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/uio.h>
+#include <linux/highmem.h>
+
+#include <asm/uaccess.h>
+#include <asm/ioctls.h>
+
+/*
+ * We use a start+len construction, which provides full use of the
+ * allocated memory.
+ * -- Florian Coosmann (FGC)
+ *
+ * Reads with count = 0 should always return 0.
+ * -- Julian Bradfield 1999-06-07.
+ *
+ * FIFOs and Pipes now generate SIGIO for both readers and writers.
+ * -- Jeremy Elson <jelson@circlemud.org> 2001-08-16
+ *
+ * pipe_read & write cleanup
+ * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09
+ */
+
+/* Drop the inode semaphore and wait for a pipe event, atomically */
+void pipe_wait(struct inode * inode)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE);
+ up(PIPE_SEM(*inode));
+ schedule();
+ finish_wait(PIPE_WAIT(*inode), &wait);
+ down(PIPE_SEM(*inode));
+}
+
+static inline int
+pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
+{
+ unsigned long copy;
+
+ while (len > 0) {
+ while (!iov->iov_len)
+ iov++;
+ copy = min_t(unsigned long, len, iov->iov_len);
+
+ if (copy_from_user(to, iov->iov_base, copy))
+ return -EFAULT;
+ to += copy;
+ len -= copy;
+ iov->iov_base += copy;
+ iov->iov_len -= copy;
+ }
+ return 0;
+}
+
+static inline int
+pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
+{
+ unsigned long copy;
+
+ while (len > 0) {
+ while (!iov->iov_len)
+ iov++;
+ copy = min_t(unsigned long, len, iov->iov_len);
+
+ if (copy_to_user(iov->iov_base, from, copy))
+ return -EFAULT;
+ from += copy;
+ len -= copy;
+ iov->iov_base += copy;
+ iov->iov_len -= copy;
+ }
+ return 0;
+}
+
+static void anon_pipe_buf_release(struct pipe_inode_info *info, struct pipe_buffer *buf)
+{
+ struct page *page = buf->page;
+
+ if (info->tmp_page) {
+ __free_page(page);
+ return;
+ }
+ info->tmp_page = page;
+}
+
+static void *anon_pipe_buf_map(struct file *file, struct pipe_inode_info *info, struct pipe_buffer *buf)
+{
+ return kmap(buf->page);
+}
+
+static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer *buf)
+{
+ kunmap(buf->page);
+}
+
+static struct pipe_buf_operations anon_pipe_buf_ops = {
+ .can_merge = 1,
+ .map = anon_pipe_buf_map,
+ .unmap = anon_pipe_buf_unmap,
+ .release = anon_pipe_buf_release,
+};
+
+static ssize_t
+pipe_readv(struct file *filp, const struct iovec *_iov,
+ unsigned long nr_segs, loff_t *ppos)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct pipe_inode_info *info;
+ int do_wakeup;
+ ssize_t ret;
+ struct iovec *iov = (struct iovec *)_iov;
+ size_t total_len;
+
+ total_len = iov_length(iov, nr_segs);
+ /* Null read succeeds. */
+ if (unlikely(total_len == 0))
+ return 0;
+
+ do_wakeup = 0;
+ ret = 0;
+ down(PIPE_SEM(*inode));
+ info = inode->i_pipe;
+ for (;;) {
+ int bufs = info->nrbufs;
+ if (bufs) {
+ int curbuf = info->curbuf;
+ struct pipe_buffer *buf = info->bufs + curbuf;
+ struct pipe_buf_operations *ops = buf->ops;
+ void *addr;
+ size_t chars = buf->len;
+ int error;
+
+ if (chars > total_len)
+ chars = total_len;
+
+ addr = ops->map(filp, info, buf);
+ error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);
+ ops->unmap(info, buf);
+ if (unlikely(error)) {
+ if (!ret) ret = -EFAULT;
+ break;
+ }
+ ret += chars;
+ buf->offset += chars;
+ buf->len -= chars;
+ if (!buf->len) {
+ buf->ops = NULL;
+ ops->release(info, buf);
+ curbuf = (curbuf + 1) & (PIPE_BUFFERS-1);
+ info->curbuf = curbuf;
+ info->nrbufs = --bufs;
+ do_wakeup = 1;
+ }
+ total_len -= chars;
+ if (!total_len)
+ break; /* common path: read succeeded */
+ }
+ if (bufs) /* More to do? */
+ continue;
+ if (!PIPE_WRITERS(*inode))
+ break;
+ if (!PIPE_WAITING_WRITERS(*inode)) {
+ /* syscall merging: Usually we must not sleep
+ * if O_NONBLOCK is set, or if we got some data.
+ * But if a writer sleeps in kernel space, then
+ * we can wait for that data without violating POSIX.
+ */
+ if (ret)
+ break;
+ if (filp->f_flags & O_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
+ }
+ }
+ if (signal_pending(current)) {
+ if (!ret) ret = -ERESTARTSYS;
+ break;
+ }
+ if (do_wakeup) {
+ wake_up_interruptible_sync(PIPE_WAIT(*inode));
+ kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT);
+ }
+ pipe_wait(inode);
+ }
+ up(PIPE_SEM(*inode));
+ /* Signal writers asynchronously that there is more room. */
+ if (do_wakeup) {
+ wake_up_interruptible(PIPE_WAIT(*inode));
+ kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT);
+ }
+ if (ret > 0)
+ file_accessed(filp);
+ return ret;
+}
+
+static ssize_t
+pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = buf, .iov_len = count };
+ return pipe_readv(filp, &iov, 1, ppos);
+}
+
+static ssize_t
+pipe_writev(struct file *filp, const struct iovec *_iov,
+ unsigned long nr_segs, loff_t *ppos)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct pipe_inode_info *info;
+ ssize_t ret;
+ int do_wakeup;
+ struct iovec *iov = (struct iovec *)_iov;
+ size_t total_len;
+ ssize_t chars;
+
+ total_len = iov_length(iov, nr_segs);
+ /* Null write succeeds. */
+ if (unlikely(total_len == 0))
+ return 0;
+
+ do_wakeup = 0;
+ ret = 0;
+ down(PIPE_SEM(*inode));
+ info = inode->i_pipe;
+
+ if (!PIPE_READERS(*inode)) {
+ send_sig(SIGPIPE, current, 0);
+ ret = -EPIPE;
+ goto out;
+ }
+
+ /* We try to merge small writes */
+ chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */
+ if (info->nrbufs && chars != 0) {
+ int lastbuf = (info->curbuf + info->nrbufs - 1) & (PIPE_BUFFERS-1);
+ struct pipe_buffer *buf = info->bufs + lastbuf;
+ struct pipe_buf_operations *ops = buf->ops;
+ int offset = buf->offset + buf->len;
+ if (ops->can_merge && offset + chars <= PAGE_SIZE) {
+ void *addr = ops->map(filp, info, buf);
+ int error = pipe_iov_copy_from_user(offset + addr, iov, chars);
+ ops->unmap(info, buf);
+ ret = error;
+ do_wakeup = 1;
+ if (error)
+ goto out;
+ buf->len += chars;
+ total_len -= chars;
+ ret = chars;
+ if (!total_len)
+ goto out;
+ }
+ }
+
+ for (;;) {
+ int bufs;
+ if (!PIPE_READERS(*inode)) {
+ send_sig(SIGPIPE, current, 0);
+ if (!ret) ret = -EPIPE;
+ break;
+ }
+ bufs = info->nrbufs;
+ if (bufs < PIPE_BUFFERS) {
+ int newbuf = (info->curbuf + bufs) & (PIPE_BUFFERS-1);
+ struct pipe_buffer *buf = info->bufs + newbuf;
+ struct page *page = info->tmp_page;
+ int error;
+
+ if (!page) {
+ page = alloc_page(GFP_HIGHUSER);
+ if (unlikely(!page)) {
+ ret = ret ? : -ENOMEM;
+ break;
+ }
+ info->tmp_page = page;
+ }
+ /* Always wakeup, even if the copy fails. Otherwise
+ * we lock up (O_NONBLOCK-)readers that sleep due to
+ * syscall merging.
+ * FIXME! Is this really true?
+ */
+ do_wakeup = 1;
+ chars = PAGE_SIZE;
+ if (chars > total_len)
+ chars = total_len;
+
+ error = pipe_iov_copy_from_user(kmap(page), iov, chars);
+ kunmap(page);
+ if (unlikely(error)) {
+ if (!ret) ret = -EFAULT;
+ break;
+ }
+ ret += chars;
+
+ /* Insert it into the buffer array */
+ buf->page = page;
+ buf->ops = &anon_pipe_buf_ops;
+ buf->offset = 0;
+ buf->len = chars;
+ info->nrbufs = ++bufs;
+ info->tmp_page = NULL;
+
+ total_len -= chars;
+ if (!total_len)
+ break;
+ }
+ if (bufs < PIPE_BUFFERS)
+ continue;
+ if (filp->f_flags & O_NONBLOCK) {
+ if (!ret) ret = -EAGAIN;
+ break;
+ }
+ if (signal_pending(current)) {
+ if (!ret) ret = -ERESTARTSYS;
+ break;
+ }
+ if (do_wakeup) {
+ wake_up_interruptible_sync(PIPE_WAIT(*inode));
+ kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN);
+ do_wakeup = 0;
+ }
+ PIPE_WAITING_WRITERS(*inode)++;
+ pipe_wait(inode);
+ PIPE_WAITING_WRITERS(*inode)--;
+ }
+out:
+ up(PIPE_SEM(*inode));
+ if (do_wakeup) {
+ wake_up_interruptible(PIPE_WAIT(*inode));
+ kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN);
+ }
+ if (ret > 0)
+ inode_update_time(inode, 1); /* mtime and ctime */
+ return ret;
+}
+
+static ssize_t
+pipe_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
+ return pipe_writev(filp, &iov, 1, ppos);
+}
+
+static ssize_t
+bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+{
+ return -EBADF;
+}
+
+static ssize_t
+bad_pipe_w(struct file *filp, const char __user *buf, size_t count, loff_t *ppos)
+{
+ return -EBADF;
+}
+
+static int
+pipe_ioctl(struct inode *pino, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct pipe_inode_info *info;
+ int count, buf, nrbufs;
+
+ switch (cmd) {
+ case FIONREAD:
+ down(PIPE_SEM(*inode));
+ info = inode->i_pipe;
+ count = 0;
+ buf = info->curbuf;
+ nrbufs = info->nrbufs;
+ while (--nrbufs >= 0) {
+ count += info->bufs[buf].len;
+ buf = (buf+1) & (PIPE_BUFFERS-1);
+ }
+ up(PIPE_SEM(*inode));
+ return put_user(count, (int __user *)arg);
+ default:
+ return -EINVAL;
+ }
+}
+
+/* No kernel lock held - fine */
+static unsigned int
+pipe_poll(struct file *filp, poll_table *wait)
+{
+ unsigned int mask;
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct pipe_inode_info *info = inode->i_pipe;
+ int nrbufs;
+
+ poll_wait(filp, PIPE_WAIT(*inode), wait);
+
+ /* Reading only -- no need for acquiring the semaphore. */
+ nrbufs = info->nrbufs;
+ mask = 0;
+ if (filp->f_mode & FMODE_READ) {
+ mask = (nrbufs > 0) ? POLLIN | POLLRDNORM : 0;
+ if (!PIPE_WRITERS(*inode) && filp->f_version != PIPE_WCOUNTER(*inode))
+ mask |= POLLHUP;
+ }
+
+ if (filp->f_mode & FMODE_WRITE) {
+ mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0;
+ if (!PIPE_READERS(*inode))
+ mask |= POLLERR;
+ }
+
+ return mask;
+}
+
+/* FIXME: most Unices do not set POLLERR for fifos */
+#define fifo_poll pipe_poll
+
+static int
+pipe_release(struct inode *inode, int decr, int decw)
+{
+ down(PIPE_SEM(*inode));
+ PIPE_READERS(*inode) -= decr;
+ PIPE_WRITERS(*inode) -= decw;
+ if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode)) {
+ free_pipe_info(inode);
+ } else {
+ wake_up_interruptible(PIPE_WAIT(*inode));
+ kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN);
+ kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT);
+ }
+ up(PIPE_SEM(*inode));
+
+ return 0;
+}
+
+static int
+pipe_read_fasync(int fd, struct file *filp, int on)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ int retval;
+
+ down(PIPE_SEM(*inode));
+ retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode));
+ up(PIPE_SEM(*inode));
+
+ if (retval < 0)
+ return retval;
+
+ return 0;
+}
+
+
+static int
+pipe_write_fasync(int fd, struct file *filp, int on)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ int retval;
+
+ down(PIPE_SEM(*inode));
+ retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode));
+ up(PIPE_SEM(*inode));
+
+ if (retval < 0)
+ return retval;
+
+ return 0;
+}
+
+
+static int
+pipe_rdwr_fasync(int fd, struct file *filp, int on)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ int retval;
+
+ down(PIPE_SEM(*inode));
+
+ retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode));
+
+ if (retval >= 0)
+ retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode));
+
+ up(PIPE_SEM(*inode));
+
+ if (retval < 0)
+ return retval;
+
+ return 0;
+}
+
+
+static int
+pipe_read_release(struct inode *inode, struct file *filp)
+{
+ pipe_read_fasync(-1, filp, 0);
+ return pipe_release(inode, 1, 0);
+}
+
+static int
+pipe_write_release(struct inode *inode, struct file *filp)
+{
+ pipe_write_fasync(-1, filp, 0);
+ return pipe_release(inode, 0, 1);
+}
+
+static int
+pipe_rdwr_release(struct inode *inode, struct file *filp)
+{
+ int decr, decw;
+
+ pipe_rdwr_fasync(-1, filp, 0);
+ decr = (filp->f_mode & FMODE_READ) != 0;
+ decw = (filp->f_mode & FMODE_WRITE) != 0;
+ return pipe_release(inode, decr, decw);
+}
+
+static int
+pipe_read_open(struct inode *inode, struct file *filp)
+{
+ /* We could have perhaps used atomic_t, but this and friends
+ below are the only places. So it doesn't seem worthwhile. */
+ down(PIPE_SEM(*inode));
+ PIPE_READERS(*inode)++;
+ up(PIPE_SEM(*inode));
+
+ return 0;
+}
+
+static int
+pipe_write_open(struct inode *inode, struct file *filp)
+{
+ down(PIPE_SEM(*inode));
+ PIPE_WRITERS(*inode)++;
+ up(PIPE_SEM(*inode));
+
+ return 0;
+}
+
+static int
+pipe_rdwr_open(struct inode *inode, struct file *filp)
+{
+ down(PIPE_SEM(*inode));
+ if (filp->f_mode & FMODE_READ)
+ PIPE_READERS(*inode)++;
+ if (filp->f_mode & FMODE_WRITE)
+ PIPE_WRITERS(*inode)++;
+ up(PIPE_SEM(*inode));
+
+ return 0;
+}
+
+/*
+ * The file_operations structs are not static because they
+ * are also used in linux/fs/fifo.c to do operations on FIFOs.
+ */
+struct file_operations read_fifo_fops = {
+ .llseek = no_llseek,
+ .read = pipe_read,
+ .readv = pipe_readv,
+ .write = bad_pipe_w,
+ .poll = fifo_poll,
+ .ioctl = pipe_ioctl,
+ .open = pipe_read_open,
+ .release = pipe_read_release,
+ .fasync = pipe_read_fasync,
+};
+
+struct file_operations write_fifo_fops = {
+ .llseek = no_llseek,
+ .read = bad_pipe_r,
+ .write = pipe_write,
+ .writev = pipe_writev,
+ .poll = fifo_poll,
+ .ioctl = pipe_ioctl,
+ .open = pipe_write_open,
+ .release = pipe_write_release,
+ .fasync = pipe_write_fasync,
+};
+
+struct file_operations rdwr_fifo_fops = {
+ .llseek = no_llseek,
+ .read = pipe_read,
+ .readv = pipe_readv,
+ .write = pipe_write,
+ .writev = pipe_writev,
+ .poll = fifo_poll,
+ .ioctl = pipe_ioctl,
+ .open = pipe_rdwr_open,
+ .release = pipe_rdwr_release,
+ .fasync = pipe_rdwr_fasync,
+};
+
+struct file_operations read_pipe_fops = {
+ .llseek = no_llseek,
+ .read = pipe_read,
+ .readv = pipe_readv,
+ .write = bad_pipe_w,
+ .poll = pipe_poll,
+ .ioctl = pipe_ioctl,
+ .open = pipe_read_open,
+ .release = pipe_read_release,
+ .fasync = pipe_read_fasync,
+};
+
+struct file_operations write_pipe_fops = {
+ .llseek = no_llseek,
+ .read = bad_pipe_r,
+ .write = pipe_write,
+ .writev = pipe_writev,
+ .poll = pipe_poll,
+ .ioctl = pipe_ioctl,
+ .open = pipe_write_open,
+ .release = pipe_write_release,
+ .fasync = pipe_write_fasync,
+};
+
+struct file_operations rdwr_pipe_fops = {
+ .llseek = no_llseek,
+ .read = pipe_read,
+ .readv = pipe_readv,
+ .write = pipe_write,
+ .writev = pipe_writev,
+ .poll = pipe_poll,
+ .ioctl = pipe_ioctl,
+ .open = pipe_rdwr_open,
+ .release = pipe_rdwr_release,
+ .fasync = pipe_rdwr_fasync,
+};
+
+void free_pipe_info(struct inode *inode)
+{
+ int i;
+ struct pipe_inode_info *info = inode->i_pipe;
+
+ inode->i_pipe = NULL;
+ for (i = 0; i < PIPE_BUFFERS; i++) {
+ struct pipe_buffer *buf = info->bufs + i;
+ if (buf->ops)
+ buf->ops->release(info, buf);
+ }
+ if (info->tmp_page)
+ __free_page(info->tmp_page);
+ kfree(info);
+}
+
+struct inode* pipe_new(struct inode* inode)
+{
+ struct pipe_inode_info *info;
+
+ info = kmalloc(sizeof(struct pipe_inode_info), GFP_KERNEL);
+ if (!info)
+ goto fail_page;
+ memset(info, 0, sizeof(*info));
+ inode->i_pipe = info;
+
+ init_waitqueue_head(PIPE_WAIT(*inode));
+ PIPE_RCOUNTER(*inode) = PIPE_WCOUNTER(*inode) = 1;
+
+ return inode;
+fail_page:
+ return NULL;
+}
+
+static struct vfsmount *pipe_mnt;
+static int pipefs_delete_dentry(struct dentry *dentry)
+{
+ return 1;
+}
+static struct dentry_operations pipefs_dentry_operations = {
+ .d_delete = pipefs_delete_dentry,
+};
+
+static struct inode * get_pipe_inode(void)
+{
+ struct inode *inode = new_inode(pipe_mnt->mnt_sb);
+
+ if (!inode)
+ goto fail_inode;
+
+ if(!pipe_new(inode))
+ goto fail_iput;
+ PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1;
+ inode->i_fop = &rdwr_pipe_fops;
+
+ /*
+ * Mark the inode dirty from the very beginning,
+ * that way it will never be moved to the dirty
+ * list because "mark_inode_dirty()" will think
+ * that it already _is_ on the dirty list.
+ */
+ inode->i_state = I_DIRTY;
+ inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ inode->i_blksize = PAGE_SIZE;
+ return inode;
+
+fail_iput:
+ iput(inode);
+fail_inode:
+ return NULL;
+}
+
+int do_pipe(int *fd)
+{
+ struct qstr this;
+ char name[32];
+ struct dentry *dentry;
+ struct inode * inode;
+ struct file *f1, *f2;
+ int error;
+ int i,j;
+
+ error = -ENFILE;
+ f1 = get_empty_filp();
+ if (!f1)
+ goto no_files;
+
+ f2 = get_empty_filp();
+ if (!f2)
+ goto close_f1;
+
+ inode = get_pipe_inode();
+ if (!inode)
+ goto close_f12;
+
+ error = get_unused_fd();
+ if (error < 0)
+ goto close_f12_inode;
+ i = error;
+
+ error = get_unused_fd();
+ if (error < 0)
+ goto close_f12_inode_i;
+ j = error;
+
+ error = -ENOMEM;
+ sprintf(name, "[%lu]", inode->i_ino);
+ this.name = name;
+ this.len = strlen(name);
+ this.hash = inode->i_ino; /* will go */
+ dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);
+ if (!dentry)
+ goto close_f12_inode_i_j;
+ dentry->d_op = &pipefs_dentry_operations;
+ d_add(dentry, inode);
+ f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt));
+ f1->f_dentry = f2->f_dentry = dget(dentry);
+ f1->f_mapping = f2->f_mapping = inode->i_mapping;
+
+ /* read file */
+ f1->f_pos = f2->f_pos = 0;
+ f1->f_flags = O_RDONLY;
+ f1->f_op = &read_pipe_fops;
+ f1->f_mode = FMODE_READ;
+ f1->f_version = 0;
+
+ /* write file */
+ f2->f_flags = O_WRONLY;
+ f2->f_op = &write_pipe_fops;
+ f2->f_mode = FMODE_WRITE;
+ f2->f_version = 0;
+
+ fd_install(i, f1);
+ fd_install(j, f2);
+ fd[0] = i;
+ fd[1] = j;
+ return 0;
+
+close_f12_inode_i_j:
+ put_unused_fd(j);
+close_f12_inode_i:
+ put_unused_fd(i);
+close_f12_inode:
+ free_pipe_info(inode);
+ iput(inode);
+close_f12:
+ put_filp(f2);
+close_f1:
+ put_filp(f1);
+no_files:
+ return error;
+}
+
+/*
+ * 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 struct super_block *pipefs_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC);
+}
+
+static struct file_system_type pipe_fs_type = {
+ .name = "pipefs",
+ .get_sb = pipefs_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
+static int __init init_pipe_fs(void)
+{
+ int err = register_filesystem(&pipe_fs_type);
+ if (!err) {
+ pipe_mnt = kern_mount(&pipe_fs_type);
+ if (IS_ERR(pipe_mnt)) {
+ err = PTR_ERR(pipe_mnt);
+ unregister_filesystem(&pipe_fs_type);
+ }
+ }
+ return err;
+}
+
+static void __exit exit_pipe_fs(void)
+{
+ unregister_filesystem(&pipe_fs_type);
+ mntput(pipe_mnt);
+}
+
+fs_initcall(init_pipe_fs);
+module_exit(exit_pipe_fs);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-02 10:45:31 +0000