--- /dev/null
+/*
+ * linux/fs/read_write.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/uio.h>
+#include <linux/fsnotify.h>
+#include <linux/security.h>
+#include <linux/export.h>
+#include <linux/syscalls.h>
+#include <linux/pagemap.h>
+#include <linux/splice.h>
+#include <linux/compat.h>
+#include "internal.h"
+
+#include <asm/uaccess.h>
+#include <asm/unistd.h>
+
+typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
+typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *);
+
+const struct file_operations generic_ro_fops = {
+ .llseek = generic_file_llseek,
+ .read_iter = generic_file_read_iter,
+ .mmap = generic_file_readonly_mmap,
+ .splice_read = generic_file_splice_read,
+};
+
+EXPORT_SYMBOL(generic_ro_fops);
+
+static inline int unsigned_offsets(struct file *file)
+{
+ return file->f_mode & FMODE_UNSIGNED_OFFSET;
+}
+
+/**
+ * vfs_setpos - update the file offset for lseek
+ * @file: file structure in question
+ * @offset: file offset to seek to
+ * @maxsize: maximum file size
+ *
+ * This is a low-level filesystem helper for updating the file offset to
+ * the value specified by @offset if the given offset is valid and it is
+ * not equal to the current file offset.
+ *
+ * Return the specified offset on success and -EINVAL on invalid offset.
+ */
+loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
+{
+ if (offset < 0 && !unsigned_offsets(file))
+ return -EINVAL;
+ if (offset > maxsize)
+ return -EINVAL;
+
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+ return offset;
+}
+EXPORT_SYMBOL(vfs_setpos);
+
+/**
+ * generic_file_llseek_size - generic llseek implementation for regular files
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @whence: type of seek
+ * @size: max size of this file in file system
+ * @eof: offset used for SEEK_END position
+ *
+ * This is a variant of generic_file_llseek that allows passing in a custom
+ * maximum file size and a custom EOF position, for e.g. hashed directories
+ *
+ * Synchronization:
+ * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
+ * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
+ * read/writes behave like SEEK_SET against seeks.
+ */
+loff_t
+generic_file_llseek_size(struct file *file, loff_t offset, int whence,
+ loff_t maxsize, loff_t eof)
+{
+ switch (whence) {
+ case SEEK_END:
+ offset += eof;
+ break;
+ case SEEK_CUR:
+ /*
+ * Here we special-case the lseek(fd, 0, SEEK_CUR)
+ * position-querying operation. Avoid rewriting the "same"
+ * f_pos value back to the file because a concurrent read(),
+ * write() or lseek() might have altered it
+ */
+ if (offset == 0)
+ return file->f_pos;
+ /*
+ * f_lock protects against read/modify/write race with other
+ * SEEK_CURs. Note that parallel writes and reads behave
+ * like SEEK_SET.
+ */
+ spin_lock(&file->f_lock);
+ offset = vfs_setpos(file, file->f_pos + offset, maxsize);
+ spin_unlock(&file->f_lock);
+ return offset;
+ case SEEK_DATA:
+ /*
+ * In the generic case the entire file is data, so as long as
+ * offset isn't at the end of the file then the offset is data.
+ */
+ if (offset >= eof)
+ return -ENXIO;
+ break;
+ case SEEK_HOLE:
+ /*
+ * There is a virtual hole at the end of the file, so as long as
+ * offset isn't i_size or larger, return i_size.
+ */
+ if (offset >= eof)
+ return -ENXIO;
+ offset = eof;
+ break;
+ }
+
+ return vfs_setpos(file, offset, maxsize);
+}
+EXPORT_SYMBOL(generic_file_llseek_size);
+
+/**
+ * generic_file_llseek - generic llseek implementation for regular files
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @whence: type of seek
+ *
+ * This is a generic implemenation of ->llseek useable for all normal local
+ * filesystems. It just updates the file offset to the value specified by
+ * @offset and @whence.
+ */
+loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file->f_mapping->host;
+
+ return generic_file_llseek_size(file, offset, whence,
+ inode->i_sb->s_maxbytes,
+ i_size_read(inode));
+}
+EXPORT_SYMBOL(generic_file_llseek);
+
+/**
+ * fixed_size_llseek - llseek implementation for fixed-sized devices
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @whence: type of seek
+ * @size: size of the file
+ *
+ */
+loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
+{
+ switch (whence) {
+ case SEEK_SET: case SEEK_CUR: case SEEK_END:
+ return generic_file_llseek_size(file, offset, whence,
+ size, size);
+ default:
+ return -EINVAL;
+ }
+}
+EXPORT_SYMBOL(fixed_size_llseek);
+
+/**
+ * noop_llseek - No Operation Performed llseek implementation
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @whence: type of seek
+ *
+ * This is an implementation of ->llseek useable for the rare special case when
+ * userspace expects the seek to succeed but the (device) file is actually not
+ * able to perform the seek. In this case you use noop_llseek() instead of
+ * falling back to the default implementation of ->llseek.
+ */
+loff_t noop_llseek(struct file *file, loff_t offset, int whence)
+{
+ return file->f_pos;
+}
+EXPORT_SYMBOL(noop_llseek);
+
+loff_t no_llseek(struct file *file, loff_t offset, int whence)
+{
+ return -ESPIPE;
+}
+EXPORT_SYMBOL(no_llseek);
+
+loff_t default_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file_inode(file);
+ loff_t retval;
+
+ mutex_lock(&inode->i_mutex);
+ switch (whence) {
+ case SEEK_END:
+ offset += i_size_read(inode);
+ break;
+ case SEEK_CUR:
+ if (offset == 0) {
+ retval = file->f_pos;
+ goto out;
+ }
+ offset += file->f_pos;
+ break;
+ case SEEK_DATA:
+ /*
+ * In the generic case the entire file is data, so as
+ * long as offset isn't at the end of the file then the
+ * offset is data.
+ */
+ if (offset >= inode->i_size) {
+ retval = -ENXIO;
+ goto out;
+ }
+ break;
+ case SEEK_HOLE:
+ /*
+ * There is a virtual hole at the end of the file, so
+ * as long as offset isn't i_size or larger, return
+ * i_size.
+ */
+ if (offset >= inode->i_size) {
+ retval = -ENXIO;
+ goto out;
+ }
+ offset = inode->i_size;
+ break;
+ }
+ retval = -EINVAL;
+ if (offset >= 0 || unsigned_offsets(file)) {
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+ retval = offset;
+ }
+out:
+ mutex_unlock(&inode->i_mutex);
+ return retval;
+}
+EXPORT_SYMBOL(default_llseek);
+
+loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
+{
+ loff_t (*fn)(struct file *, loff_t, int);
+
+ fn = no_llseek;
+ if (file->f_mode & FMODE_LSEEK) {
+ if (file->f_op->llseek)
+ fn = file->f_op->llseek;
+ }
+ return fn(file, offset, whence);
+}
+EXPORT_SYMBOL(vfs_llseek);
+
+static inline struct fd fdget_pos(int fd)
+{
+ return __to_fd(__fdget_pos(fd));
+}
+
+static inline void fdput_pos(struct fd f)
+{
+ if (f.flags & FDPUT_POS_UNLOCK)
+ mutex_unlock(&f.file->f_pos_lock);
+ fdput(f);
+}
+
+SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
+{
+ off_t retval;
+ struct fd f = fdget_pos(fd);
+ if (!f.file)
+ return -EBADF;
+
+ retval = -EINVAL;
+ if (whence <= SEEK_MAX) {
+ loff_t res = vfs_llseek(f.file, offset, whence);
+ retval = res;
+ if (res != (loff_t)retval)
+ retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
+ }
+ fdput_pos(f);
+ return retval;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
+{
+ return sys_lseek(fd, offset, whence);
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_LLSEEK
+SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
+ unsigned long, offset_low, loff_t __user *, result,
+ unsigned int, whence)
+{
+ int retval;
+ struct fd f = fdget_pos(fd);
+ loff_t offset;
+
+ if (!f.file)
+ return -EBADF;
+
+ retval = -EINVAL;
+ if (whence > SEEK_MAX)
+ goto out_putf;
+
+ offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
+ whence);
+
+ retval = (int)offset;
+ if (offset >= 0) {
+ retval = -EFAULT;
+ if (!copy_to_user(result, &offset, sizeof(offset)))
+ retval = 0;
+ }
+out_putf:
+ fdput_pos(f);
+ return retval;
+}
+#endif
+
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+ struct kiocb kiocb;
+ ssize_t ret;
+
+ if (!file->f_op->read_iter)
+ return -EINVAL;
+
+ init_sync_kiocb(&kiocb, file);
+ kiocb.ki_pos = *ppos;
+
+ iter->type |= READ;
+ ret = file->f_op->read_iter(&kiocb, iter);
+ BUG_ON(ret == -EIOCBQUEUED);
+ if (ret > 0)
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+EXPORT_SYMBOL(vfs_iter_read);
+
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+ struct kiocb kiocb;
+ ssize_t ret;
+
+ if (!file->f_op->write_iter)
+ return -EINVAL;
+
+ init_sync_kiocb(&kiocb, file);
+ kiocb.ki_pos = *ppos;
+
+ iter->type |= WRITE;
+ ret = file->f_op->write_iter(&kiocb, iter);
+ BUG_ON(ret == -EIOCBQUEUED);
+ if (ret > 0)
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+EXPORT_SYMBOL(vfs_iter_write);
+
+/*
+ * rw_verify_area doesn't like huge counts. We limit
+ * them to something that fits in "int" so that others
+ * won't have to do range checks all the time.
+ */
+int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
+{
+ struct inode *inode;
+ loff_t pos;
+ int retval = -EINVAL;
+
+ inode = file_inode(file);
+ if (unlikely((ssize_t) count < 0))
+ return retval;
+ pos = *ppos;
+ if (unlikely(pos < 0)) {
+ if (!unsigned_offsets(file))
+ return retval;
+ if (count >= -pos) /* both values are in 0..LLONG_MAX */
+ return -EOVERFLOW;
+ } else if (unlikely((loff_t) (pos + count) < 0)) {
+ if (!unsigned_offsets(file))
+ return retval;
+ }
+
+ if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
+ retval = locks_mandatory_area(
+ read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
+ inode, file, pos, count);
+ if (retval < 0)
+ return retval;
+ }
+ retval = security_file_permission(file,
+ read_write == READ ? MAY_READ : MAY_WRITE);
+ if (retval)
+ return retval;
+ return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
+}
+
+static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = buf, .iov_len = len };
+ struct kiocb kiocb;
+ struct iov_iter iter;
+ ssize_t ret;
+
+ init_sync_kiocb(&kiocb, filp);
+ kiocb.ki_pos = *ppos;
+ iov_iter_init(&iter, READ, &iov, 1, len);
+
+ ret = filp->f_op->read_iter(&kiocb, &iter);
+ BUG_ON(ret == -EIOCBQUEUED);
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+
+ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
+ loff_t *pos)
+{
+ if (file->f_op->read)
+ return file->f_op->read(file, buf, count, pos);
+ else if (file->f_op->read_iter)
+ return new_sync_read(file, buf, count, pos);
+ else
+ return -EINVAL;
+}
+EXPORT_SYMBOL(__vfs_read);
+
+ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
+{
+ ssize_t ret;
+
+ if (!(file->f_mode & FMODE_READ))
+ return -EBADF;
+ if (!(file->f_mode & FMODE_CAN_READ))
+ return -EINVAL;
+ if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
+ return -EFAULT;
+
+ ret = rw_verify_area(READ, file, pos, count);
+ if (ret >= 0) {
+ count = ret;
+ ret = __vfs_read(file, buf, count, pos);
+ if (ret > 0) {
+ fsnotify_access(file);
+ add_rchar(current, ret);
+ }
+ inc_syscr(current);
+ }
+
+ return ret;
+}
+
+EXPORT_SYMBOL(vfs_read);
+
+static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
+ struct kiocb kiocb;
+ struct iov_iter iter;
+ ssize_t ret;
+
+ init_sync_kiocb(&kiocb, filp);
+ kiocb.ki_pos = *ppos;
+ iov_iter_init(&iter, WRITE, &iov, 1, len);
+
+ ret = filp->f_op->write_iter(&kiocb, &iter);
+ BUG_ON(ret == -EIOCBQUEUED);
+ if (ret > 0)
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+
+ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
+ loff_t *pos)
+{
+ if (file->f_op->write)
+ return file->f_op->write(file, p, count, pos);
+ else if (file->f_op->write_iter)
+ return new_sync_write(file, p, count, pos);
+ else
+ return -EINVAL;
+}
+EXPORT_SYMBOL(__vfs_write);
+
+ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
+{
+ mm_segment_t old_fs;
+ const char __user *p;
+ ssize_t ret;
+
+ if (!(file->f_mode & FMODE_CAN_WRITE))
+ return -EINVAL;
+
+ old_fs = get_fs();
+ set_fs(get_ds());
+ p = (__force const char __user *)buf;
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
+ ret = __vfs_write(file, p, count, pos);
+ set_fs(old_fs);
+ if (ret > 0) {
+ fsnotify_modify(file);
+ add_wchar(current, ret);
+ }
+ inc_syscw(current);
+ return ret;
+}
+
+EXPORT_SYMBOL(__kernel_write);
+
+ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
+{
+ ssize_t ret;
+
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EBADF;
+ if (!(file->f_mode & FMODE_CAN_WRITE))
+ return -EINVAL;
+ if (unlikely(!access_ok(VERIFY_READ, buf, count)))
+ return -EFAULT;
+
+ ret = rw_verify_area(WRITE, file, pos, count);
+ if (ret >= 0) {
+ count = ret;
+ file_start_write(file);
+ ret = __vfs_write(file, buf, count, pos);
+ if (ret > 0) {
+ fsnotify_modify(file);
+ add_wchar(current, ret);
+ }
+ inc_syscw(current);
+ file_end_write(file);
+ }
+
+ return ret;
+}
+
+EXPORT_SYMBOL(vfs_write);
+
+static inline loff_t file_pos_read(struct file *file)
+{
+ return file->f_pos;
+}
+
+static inline void file_pos_write(struct file *file, loff_t pos)
+{
+ file->f_pos = pos;
+}
+
+SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
+{
+ struct fd f = fdget_pos(fd);
+ ssize_t ret = -EBADF;
+
+ if (f.file) {
+ loff_t pos = file_pos_read(f.file);
+ ret = vfs_read(f.file, buf, count, &pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
+ fdput_pos(f);
+ }
+ return ret;
+}
+
+SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
+ size_t, count)
+{
+ struct fd f = fdget_pos(fd);
+ ssize_t ret = -EBADF;
+
+ if (f.file) {
+ loff_t pos = file_pos_read(f.file);
+ ret = vfs_write(f.file, buf, count, &pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
+ fdput_pos(f);
+ }
+
+ return ret;
+}
+
+SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
+ size_t, count, loff_t, pos)
+{
+ struct fd f;
+ ssize_t ret = -EBADF;
+
+ if (pos < 0)
+ return -EINVAL;
+
+ f = fdget(fd);
+ if (f.file) {
+ ret = -ESPIPE;
+ if (f.file->f_mode & FMODE_PREAD)
+ ret = vfs_read(f.file, buf, count, &pos);
+ fdput(f);
+ }
+
+ return ret;
+}
+
+SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
+ size_t, count, loff_t, pos)
+{
+ struct fd f;
+ ssize_t ret = -EBADF;
+
+ if (pos < 0)
+ return -EINVAL;
+
+ f = fdget(fd);
+ if (f.file) {
+ ret = -ESPIPE;
+ if (f.file->f_mode & FMODE_PWRITE)
+ ret = vfs_write(f.file, buf, count, &pos);
+ fdput(f);
+ }
+
+ return ret;
+}
+
+/*
+ * Reduce an iovec's length in-place. Return the resulting number of segments
+ */
+unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
+{
+ unsigned long seg = 0;
+ size_t len = 0;
+
+ while (seg < nr_segs) {
+ seg++;
+ if (len + iov->iov_len >= to) {
+ iov->iov_len = to - len;
+ break;
+ }
+ len += iov->iov_len;
+ iov++;
+ }
+ return seg;
+}
+EXPORT_SYMBOL(iov_shorten);
+
+static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
+ loff_t *ppos, iter_fn_t fn)
+{
+ struct kiocb kiocb;
+ ssize_t ret;
+
+ init_sync_kiocb(&kiocb, filp);
+ kiocb.ki_pos = *ppos;
+
+ ret = fn(&kiocb, iter);
+ BUG_ON(ret == -EIOCBQUEUED);
+ *ppos = kiocb.ki_pos;
+ return ret;
+}
+
+/* Do it by hand, with file-ops */
+static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
+ loff_t *ppos, io_fn_t fn)
+{
+ ssize_t ret = 0;
+
+ while (iov_iter_count(iter)) {
+ struct iovec iovec = iov_iter_iovec(iter);
+ ssize_t nr;
+
+ nr = fn(filp, iovec.iov_base, iovec.iov_len, ppos);
+
+ if (nr < 0) {
+ if (!ret)
+ ret = nr;
+ break;
+ }
+ ret += nr;
+ if (nr != iovec.iov_len)
+ break;
+ iov_iter_advance(iter, nr);
+ }
+
+ return ret;
+}
+
+/* A write operation does a read from user space and vice versa */
+#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
+
+ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
+ unsigned long nr_segs, unsigned long fast_segs,
+ struct iovec *fast_pointer,
+ struct iovec **ret_pointer)
+{
+ unsigned long seg;
+ ssize_t ret;
+ struct iovec *iov = fast_pointer;
+
+ /*
+ * SuS says "The readv() function *may* fail if the iovcnt argument
+ * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
+ * traditionally returned zero for zero segments, so...
+ */
+ if (nr_segs == 0) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * First get the "struct iovec" from user memory and
+ * verify all the pointers
+ */
+ if (nr_segs > UIO_MAXIOV) {
+ ret = -EINVAL;
+ goto out;
+ }
+ if (nr_segs > fast_segs) {
+ iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
+ if (iov == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ /*
+ * According to the Single Unix Specification we should return EINVAL
+ * if an element length is < 0 when cast to ssize_t or if the
+ * total length would overflow the ssize_t return value of the
+ * system call.
+ *
+ * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
+ * overflow case.
+ */
+ ret = 0;
+ for (seg = 0; seg < nr_segs; seg++) {
+ void __user *buf = iov[seg].iov_base;
+ ssize_t len = (ssize_t)iov[seg].iov_len;
+
+ /* see if we we're about to use an invalid len or if
+ * it's about to overflow ssize_t */
+ if (len < 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+ if (type >= 0
+ && unlikely(!access_ok(vrfy_dir(type), buf, len))) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (len > MAX_RW_COUNT - ret) {
+ len = MAX_RW_COUNT - ret;
+ iov[seg].iov_len = len;
+ }
+ ret += len;
+ }
+out:
+ *ret_pointer = iov;
+ return ret;
+}
+
+static ssize_t do_readv_writev(int type, struct file *file,
+ const struct iovec __user * uvector,
+ unsigned long nr_segs, loff_t *pos)
+{
+ size_t tot_len;
+ struct iovec iovstack[UIO_FASTIOV];
+ struct iovec *iov = iovstack;
+ struct iov_iter iter;
+ ssize_t ret;
+ io_fn_t fn;
+ iter_fn_t iter_fn;
+
+ ret = import_iovec(type, uvector, nr_segs,
+ ARRAY_SIZE(iovstack), &iov, &iter);
+ if (ret < 0)
+ return ret;
+
+ tot_len = iov_iter_count(&iter);
+ if (!tot_len)
+ goto out;
+ ret = rw_verify_area(type, file, pos, tot_len);
+ if (ret < 0)
+ goto out;
+
+ if (type == READ) {
+ fn = file->f_op->read;
+ iter_fn = file->f_op->read_iter;
+ } else {
+ fn = (io_fn_t)file->f_op->write;
+ iter_fn = file->f_op->write_iter;
+ file_start_write(file);
+ }
+
+ if (iter_fn)
+ ret = do_iter_readv_writev(file, &iter, pos, iter_fn);
+ else
+ ret = do_loop_readv_writev(file, &iter, pos, fn);
+
+ if (type != READ)
+ file_end_write(file);
+
+out:
+ kfree(iov);
+ if ((ret + (type == READ)) > 0) {
+ if (type == READ)
+ fsnotify_access(file);
+ else
+ fsnotify_modify(file);
+ }
+ return ret;
+}
+
+ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
+ unsigned long vlen, loff_t *pos)
+{
+ if (!(file->f_mode & FMODE_READ))
+ return -EBADF;
+ if (!(file->f_mode & FMODE_CAN_READ))
+ return -EINVAL;
+
+ return do_readv_writev(READ, file, vec, vlen, pos);
+}
+
+EXPORT_SYMBOL(vfs_readv);
+
+ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
+ unsigned long vlen, loff_t *pos)
+{
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EBADF;
+ if (!(file->f_mode & FMODE_CAN_WRITE))
+ return -EINVAL;
+
+ return do_readv_writev(WRITE, file, vec, vlen, pos);
+}
+
+EXPORT_SYMBOL(vfs_writev);
+
+SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
+ unsigned long, vlen)
+{
+ struct fd f = fdget_pos(fd);
+ ssize_t ret = -EBADF;
+
+ if (f.file) {
+ loff_t pos = file_pos_read(f.file);
+ ret = vfs_readv(f.file, vec, vlen, &pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
+ fdput_pos(f);
+ }
+
+ if (ret > 0)
+ add_rchar(current, ret);
+ inc_syscr(current);
+ return ret;
+}
+
+SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
+ unsigned long, vlen)
+{
+ struct fd f = fdget_pos(fd);
+ ssize_t ret = -EBADF;
+
+ if (f.file) {
+ loff_t pos = file_pos_read(f.file);
+ ret = vfs_writev(f.file, vec, vlen, &pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
+ fdput_pos(f);
+ }
+
+ if (ret > 0)
+ add_wchar(current, ret);
+ inc_syscw(current);
+ return ret;
+}
+
+static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
+{
+#define HALF_LONG_BITS (BITS_PER_LONG / 2)
+ return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
+}
+
+SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
+ unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
+{
+ loff_t pos = pos_from_hilo(pos_h, pos_l);
+ struct fd f;
+ ssize_t ret = -EBADF;
+
+ if (pos < 0)
+ return -EINVAL;
+
+ f = fdget(fd);
+ if (f.file) {
+ ret = -ESPIPE;
+ if (f.file->f_mode & FMODE_PREAD)
+ ret = vfs_readv(f.file, vec, vlen, &pos);
+ fdput(f);
+ }
+
+ if (ret > 0)
+ add_rchar(current, ret);
+ inc_syscr(current);
+ return ret;
+}
+
+SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
+ unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
+{
+ loff_t pos = pos_from_hilo(pos_h, pos_l);
+ struct fd f;
+ ssize_t ret = -EBADF;
+
+ if (pos < 0)
+ return -EINVAL;
+
+ f = fdget(fd);
+ if (f.file) {
+ ret = -ESPIPE;
+ if (f.file->f_mode & FMODE_PWRITE)
+ ret = vfs_writev(f.file, vec, vlen, &pos);
+ fdput(f);
+ }
+
+ if (ret > 0)
+ add_wchar(current, ret);
+ inc_syscw(current);
+ return ret;
+}
+
+#ifdef CONFIG_COMPAT
+
+static ssize_t compat_do_readv_writev(int type, struct file *file,
+ const struct compat_iovec __user *uvector,
+ unsigned long nr_segs, loff_t *pos)
+{
+ compat_ssize_t tot_len;
+ struct iovec iovstack[UIO_FASTIOV];
+ struct iovec *iov = iovstack;
+ struct iov_iter iter;
+ ssize_t ret;
+ io_fn_t fn;
+ iter_fn_t iter_fn;
+
+ ret = compat_import_iovec(type, uvector, nr_segs,
+ UIO_FASTIOV, &iov, &iter);
+ if (ret < 0)
+ return ret;
+
+ tot_len = iov_iter_count(&iter);
+ if (!tot_len)
+ goto out;
+ ret = rw_verify_area(type, file, pos, tot_len);
+ if (ret < 0)
+ goto out;
+
+ if (type == READ) {
+ fn = file->f_op->read;
+ iter_fn = file->f_op->read_iter;
+ } else {
+ fn = (io_fn_t)file->f_op->write;
+ iter_fn = file->f_op->write_iter;
+ file_start_write(file);
+ }
+
+ if (iter_fn)
+ ret = do_iter_readv_writev(file, &iter, pos, iter_fn);
+ else
+ ret = do_loop_readv_writev(file, &iter, pos, fn);
+
+ if (type != READ)
+ file_end_write(file);
+
+out:
+ kfree(iov);
+ if ((ret + (type == READ)) > 0) {
+ if (type == READ)
+ fsnotify_access(file);
+ else
+ fsnotify_modify(file);
+ }
+ return ret;
+}
+
+static size_t compat_readv(struct file *file,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, loff_t *pos)
+{
+ ssize_t ret = -EBADF;
+
+ if (!(file->f_mode & FMODE_READ))
+ goto out;
+
+ ret = -EINVAL;
+ if (!(file->f_mode & FMODE_CAN_READ))
+ goto out;
+
+ ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
+
+out:
+ if (ret > 0)
+ add_rchar(current, ret);
+ inc_syscr(current);
+ return ret;
+}
+
+COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
+ const struct compat_iovec __user *,vec,
+ compat_ulong_t, vlen)
+{
+ struct fd f = fdget_pos(fd);
+ ssize_t ret;
+ loff_t pos;
+
+ if (!f.file)
+ return -EBADF;
+ pos = f.file->f_pos;
+ ret = compat_readv(f.file, vec, vlen, &pos);
+ if (ret >= 0)
+ f.file->f_pos = pos;
+ fdput_pos(f);
+ return ret;
+}
+
+static long __compat_sys_preadv64(unsigned long fd,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, loff_t pos)
+{
+ struct fd f;
+ ssize_t ret;
+
+ if (pos < 0)
+ return -EINVAL;
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+ ret = -ESPIPE;
+ if (f.file->f_mode & FMODE_PREAD)
+ ret = compat_readv(f.file, vec, vlen, &pos);
+ fdput(f);
+ return ret;
+}
+
+#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
+COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
+ const struct compat_iovec __user *,vec,
+ unsigned long, vlen, loff_t, pos)
+{
+ return __compat_sys_preadv64(fd, vec, vlen, pos);
+}
+#endif
+
+COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
+ const struct compat_iovec __user *,vec,
+ compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
+{
+ loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+
+ return __compat_sys_preadv64(fd, vec, vlen, pos);
+}
+
+static size_t compat_writev(struct file *file,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, loff_t *pos)
+{
+ ssize_t ret = -EBADF;
+
+ if (!(file->f_mode & FMODE_WRITE))
+ goto out;
+
+ ret = -EINVAL;
+ if (!(file->f_mode & FMODE_CAN_WRITE))
+ goto out;
+
+ ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
+
+out:
+ if (ret > 0)
+ add_wchar(current, ret);
+ inc_syscw(current);
+ return ret;
+}
+
+COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
+ const struct compat_iovec __user *, vec,
+ compat_ulong_t, vlen)
+{
+ struct fd f = fdget_pos(fd);
+ ssize_t ret;
+ loff_t pos;
+
+ if (!f.file)
+ return -EBADF;
+ pos = f.file->f_pos;
+ ret = compat_writev(f.file, vec, vlen, &pos);
+ if (ret >= 0)
+ f.file->f_pos = pos;
+ fdput_pos(f);
+ return ret;
+}
+
+static long __compat_sys_pwritev64(unsigned long fd,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, loff_t pos)
+{
+ struct fd f;
+ ssize_t ret;
+
+ if (pos < 0)
+ return -EINVAL;
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+ ret = -ESPIPE;
+ if (f.file->f_mode & FMODE_PWRITE)
+ ret = compat_writev(f.file, vec, vlen, &pos);
+ fdput(f);
+ return ret;
+}
+
+#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64
+COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
+ const struct compat_iovec __user *,vec,
+ unsigned long, vlen, loff_t, pos)
+{
+ return __compat_sys_pwritev64(fd, vec, vlen, pos);
+}
+#endif
+
+COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
+ const struct compat_iovec __user *,vec,
+ compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
+{
+ loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+
+ return __compat_sys_pwritev64(fd, vec, vlen, pos);
+}
+#endif
+
+static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
+ size_t count, loff_t max)
+{
+ struct fd in, out;
+ struct inode *in_inode, *out_inode;
+ loff_t pos;
+ loff_t out_pos;
+ ssize_t retval;
+ int fl;
+
+ /*
+ * Get input file, and verify that it is ok..
+ */
+ retval = -EBADF;
+ in = fdget(in_fd);
+ if (!in.file)
+ goto out;
+ if (!(in.file->f_mode & FMODE_READ))
+ goto fput_in;
+ retval = -ESPIPE;
+ if (!ppos) {
+ pos = in.file->f_pos;
+ } else {
+ pos = *ppos;
+ if (!(in.file->f_mode & FMODE_PREAD))
+ goto fput_in;
+ }
+ retval = rw_verify_area(READ, in.file, &pos, count);
+ if (retval < 0)
+ goto fput_in;
+ count = retval;
+
+ /*
+ * Get output file, and verify that it is ok..
+ */
+ retval = -EBADF;
+ out = fdget(out_fd);
+ if (!out.file)
+ goto fput_in;
+ if (!(out.file->f_mode & FMODE_WRITE))
+ goto fput_out;
+ retval = -EINVAL;
+ in_inode = file_inode(in.file);
+ out_inode = file_inode(out.file);
+ out_pos = out.file->f_pos;
+ retval = rw_verify_area(WRITE, out.file, &out_pos, count);
+ if (retval < 0)
+ goto fput_out;
+ count = retval;
+
+ if (!max)
+ max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
+
+ if (unlikely(pos + count > max)) {
+ retval = -EOVERFLOW;
+ if (pos >= max)
+ goto fput_out;
+ count = max - pos;
+ }
+
+ fl = 0;
+#if 0
+ /*
+ * We need to debate whether we can enable this or not. The
+ * man page documents EAGAIN return for the output at least,
+ * and the application is arguably buggy if it doesn't expect
+ * EAGAIN on a non-blocking file descriptor.
+ */
+ if (in.file->f_flags & O_NONBLOCK)
+ fl = SPLICE_F_NONBLOCK;
+#endif
+ file_start_write(out.file);
+ retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
+ file_end_write(out.file);
+
+ if (retval > 0) {
+ add_rchar(current, retval);
+ add_wchar(current, retval);
+ fsnotify_access(in.file);
+ fsnotify_modify(out.file);
+ out.file->f_pos = out_pos;
+ if (ppos)
+ *ppos = pos;
+ else
+ in.file->f_pos = pos;
+ }
+
+ inc_syscr(current);
+ inc_syscw(current);
+ if (pos > max)
+ retval = -EOVERFLOW;
+
+fput_out:
+ fdput(out);
+fput_in:
+ fdput(in);
+out:
+ return retval;
+}
+
+SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
+{
+ loff_t pos;
+ off_t off;
+ ssize_t ret;
+
+ if (offset) {
+ if (unlikely(get_user(off, offset)))
+ return -EFAULT;
+ pos = off;
+ ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
+ if (unlikely(put_user(pos, offset)))
+ return -EFAULT;
+ return ret;
+ }
+
+ return do_sendfile(out_fd, in_fd, NULL, count, 0);
+}
+
+SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
+{
+ loff_t pos;
+ ssize_t ret;
+
+ if (offset) {
+ if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
+ return -EFAULT;
+ ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
+ if (unlikely(put_user(pos, offset)))
+ return -EFAULT;
+ return ret;
+ }
+
+ return do_sendfile(out_fd, in_fd, NULL, count, 0);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,
+ compat_off_t __user *, offset, compat_size_t, count)
+{
+ loff_t pos;
+ off_t off;
+ ssize_t ret;
+
+ if (offset) {
+ if (unlikely(get_user(off, offset)))
+ return -EFAULT;
+ pos = off;
+ ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
+ if (unlikely(put_user(pos, offset)))
+ return -EFAULT;
+ return ret;
+ }
+
+ return do_sendfile(out_fd, in_fd, NULL, count, 0);
+}
+
+COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
+ compat_loff_t __user *, offset, compat_size_t, count)
+{
+ loff_t pos;
+ ssize_t ret;
+
+ if (offset) {
+ if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
+ return -EFAULT;
+ ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
+ if (unlikely(put_user(pos, offset)))
+ return -EFAULT;
+ return ret;
+ }
+
+ return do_sendfile(out_fd, in_fd, NULL, count, 0);
+}
+#endif
Code Review / kvmfornfv.git / blobdiff