1 files changed, 730 insertions, 0 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
new file mode 100644
index 000000000000..6be4b1a1956b
--- /dev/null
+++ b/fs/read_write.c
@@ -0,0 +1,730 @@
+/*
+ *  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/smp_lock.h>
+#include <linux/dnotify.h>
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/syscalls.h>
+
+#include <asm/uaccess.h>
+#include <asm/unistd.h>
+
+struct file_operations generic_ro_fops = {
+        .llseek         = generic_file_llseek,
+        .read           = generic_file_read,
+        .mmap           = generic_file_readonly_mmap,
+        .sendfile       = generic_file_sendfile,
+};
+
+EXPORT_SYMBOL(generic_ro_fops);
+
+loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
+{
+        long long retval;
+        struct inode *inode = file->f_mapping->host;
+
+        down(&inode->i_sem);
+        switch (origin) {
+                case 2:
+                        offset += inode->i_size;
+                        break;
+                case 1:
+                        offset += file->f_pos;
+        }
+        retval = -EINVAL;
+        if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
+                if (offset != file->f_pos) {
+                        file->f_pos = offset;
+                        file->f_version = 0;
+                }
+                retval = offset;
+        }
+        up(&inode->i_sem);
+        return retval;
+}
+
+EXPORT_SYMBOL(generic_file_llseek);
+
+loff_t remote_llseek(struct file *file, loff_t offset, int origin)
+{
+        long long retval;
+
+        lock_kernel();
+        switch (origin) {
+                case 2:
+                        offset += i_size_read(file->f_dentry->d_inode);
+                        break;
+                case 1:
+                        offset += file->f_pos;
+        }
+        retval = -EINVAL;
+        if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) {
+                if (offset != file->f_pos) {
+                        file->f_pos = offset;
+                        file->f_version = 0;
+                }
+                retval = offset;
+        }
+        unlock_kernel();
+        return retval;
+}
+EXPORT_SYMBOL(remote_llseek);
+
+loff_t no_llseek(struct file *file, loff_t offset, int origin)
+{
+        return -ESPIPE;
+}
+EXPORT_SYMBOL(no_llseek);
+
+loff_t default_llseek(struct file *file, loff_t offset, int origin)
+{
+        long long retval;
+
+        lock_kernel();
+        switch (origin) {
+                case 2:
+                        offset += i_size_read(file->f_dentry->d_inode);
+                        break;
+                case 1:
+                        offset += file->f_pos;
+        }
+        retval = -EINVAL;
+        if (offset >= 0) {
+                if (offset != file->f_pos) {
+                        file->f_pos = offset;
+                        file->f_version = 0;
+                }
+                retval = offset;
+        }
+        unlock_kernel();
+        return retval;
+}
+EXPORT_SYMBOL(default_llseek);
+
+loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
+{
+        loff_t (*fn)(struct file *, loff_t, int);
+
+        fn = no_llseek;
+        if (file->f_mode & FMODE_LSEEK) {
+                fn = default_llseek;
+                if (file->f_op && file->f_op->llseek)
+                        fn = file->f_op->llseek;
+        }
+        return fn(file, offset, origin);
+}
+EXPORT_SYMBOL(vfs_llseek);
+
+asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
+{
+        off_t retval;
+        struct file * file;
+        int fput_needed;
+
+        retval = -EBADF;
+        file = fget_light(fd, &fput_needed);
+        if (!file)
+                goto bad;
+
+        retval = -EINVAL;
+        if (origin <= 2) {
+                loff_t res = vfs_llseek(file, offset, origin);
+                retval = res;
+                if (res != (loff_t)retval)
+                        retval = -EOVERFLOW;    /* LFS: should only happen on 32 bit platforms */
+        }
+        fput_light(file, fput_needed);
+bad:
+        return retval;
+}
+
+#ifdef __ARCH_WANT_SYS_LLSEEK
+asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
+                           unsigned long offset_low, loff_t __user * result,
+                           unsigned int origin)
+{
+        int retval;
+        struct file * file;
+        loff_t offset;
+        int fput_needed;
+
+        retval = -EBADF;
+        file = fget_light(fd, &fput_needed);
+        if (!file)
+                goto bad;
+
+        retval = -EINVAL;
+        if (origin > 2)
+                goto out_putf;
+
+        offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
+                        origin);
+
+        retval = (int)offset;
+        if (offset >= 0) {
+                retval = -EFAULT;
+                if (!copy_to_user(result, &offset, sizeof(offset)))
+                        retval = 0;
+        }
+out_putf:
+        fput_light(file, fput_needed);
+bad:
+        return retval;
+}
+#endif
+
+
+int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
+{
+        struct inode *inode;
+        loff_t pos;
+
+        if (unlikely(count > file->f_maxcount))
+                goto Einval;
+        pos = *ppos;
+        if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
+                goto Einval;
+
+        inode = file->f_dentry->d_inode;
+        if (inode->i_flock && MANDATORY_LOCK(inode))
+                return locks_mandatory_area(read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, inode, file, pos, count);
+        return 0;
+
+Einval:
+        return -EINVAL;
+}
+
+ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
+{
+        struct kiocb kiocb;
+        ssize_t ret;
+
+        init_sync_kiocb(&kiocb, filp);
+        kiocb.ki_pos = *ppos;
+        ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos);
+        if (-EIOCBQUEUED == ret)
+                ret = wait_on_sync_kiocb(&kiocb);
+        *ppos = kiocb.ki_pos;
+        return ret;
+}
+
+EXPORT_SYMBOL(do_sync_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_op || (!file->f_op->read && !file->f_op->aio_read))
+                return -EINVAL;
+        if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
+                return -EFAULT;
+
+        ret = rw_verify_area(READ, file, pos, count);
+        if (!ret) {
+                ret = security_file_permission (file, MAY_READ);
+                if (!ret) {
+                        if (file->f_op->read)
+                                ret = file->f_op->read(file, buf, count, pos);
+                        else
+                                ret = do_sync_read(file, buf, count, pos);
+                        if (ret > 0) {
+                                dnotify_parent(file->f_dentry, DN_ACCESS);
+                                current->rchar += ret;
+                        }
+                        current->syscr++;
+                }
+        }
+
+        return ret;
+}
+
+EXPORT_SYMBOL(vfs_read);
+
+ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
+{
+        struct kiocb kiocb;
+        ssize_t ret;
+
+        init_sync_kiocb(&kiocb, filp);
+        kiocb.ki_pos = *ppos;
+        ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos);
+        if (-EIOCBQUEUED == ret)
+                ret = wait_on_sync_kiocb(&kiocb);
+        *ppos = kiocb.ki_pos;
+        return ret;
+}
+
+EXPORT_SYMBOL(do_sync_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_op || (!file->f_op->write && !file->f_op->aio_write))
+                return -EINVAL;
+        if (unlikely(!access_ok(VERIFY_READ, buf, count)))
+                return -EFAULT;
+
+        ret = rw_verify_area(WRITE, file, pos, count);
+        if (!ret) {
+                ret = security_file_permission (file, MAY_WRITE);
+                if (!ret) {
+                        if (file->f_op->write)
+                                ret = file->f_op->write(file, buf, count, pos);
+                        else
+                                ret = do_sync_write(file, buf, count, pos);
+                        if (ret > 0) {
+                                dnotify_parent(file->f_dentry, DN_MODIFY);
+                                current->wchar += ret;
+                        }
+                        current->syscw++;
+                }
+        }
+
+        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;
+}
+
+asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
+{
+        struct file *file;
+        ssize_t ret = -EBADF;
+        int fput_needed;
+
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                loff_t pos = file_pos_read(file);
+                ret = vfs_read(file, buf, count, &pos);
+                file_pos_write(file, pos);
+                fput_light(file, fput_needed);
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(sys_read);
+
+asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
+{
+        struct file *file;
+        ssize_t ret = -EBADF;
+        int fput_needed;
+
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                loff_t pos = file_pos_read(file);
+                ret = vfs_write(file, buf, count, &pos);
+                file_pos_write(file, pos);
+                fput_light(file, fput_needed);
+        }
+
+        return ret;
+}
+
+asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
+                             size_t count, loff_t pos)
+{
+        struct file *file;
+        ssize_t ret = -EBADF;
+        int fput_needed;
+
+        if (pos < 0)
+                return -EINVAL;
+
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                ret = -ESPIPE;
+                if (file->f_mode & FMODE_PREAD)
+                        ret = vfs_read(file, buf, count, &pos);
+                fput_light(file, fput_needed);
+        }
+
+        return ret;
+}
+
+asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
+                              size_t count, loff_t pos)
+{
+        struct file *file;
+        ssize_t ret = -EBADF;
+        int fput_needed;
+
+        if (pos < 0)
+                return -EINVAL;
+
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                ret = -ESPIPE;
+                if (file->f_mode & FMODE_PWRITE)  
+                        ret = vfs_write(file, buf, count, &pos);
+                fput_light(file, fput_needed);
+        }
+
+        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);
+
+/* A write operation does a read from user space and vice versa */
+#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
+
+static ssize_t do_readv_writev(int type, struct file *file,
+                               const struct iovec __user * uvector,
+                               unsigned long nr_segs, loff_t *pos)
+{
+        typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
+        typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);
+
+        size_t tot_len;
+        struct iovec iovstack[UIO_FASTIOV];
+        struct iovec *iov=iovstack, *vector;
+        ssize_t ret;
+        int seg;
+        io_fn_t fn;
+        iov_fn_t fnv;
+
+        /*
+         * 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...
+         */
+        ret = 0;
+        if (nr_segs == 0)
+                goto out;
+
+        /*
+         * First get the "struct iovec" from user memory and
+         * verify all the pointers
+         */
+        ret = -EINVAL;
+        if ((nr_segs > UIO_MAXIOV) || (nr_segs <= 0))
+                goto out;
+        if (!file->f_op)
+                goto out;
+        if (nr_segs > UIO_FASTIOV) {
+                ret = -ENOMEM;
+                iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
+                if (!iov)
+                        goto out;
+        }
+        ret = -EFAULT;
+        if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector)))
+                goto out;
+
+        /*
+         * Single unix specification:
+         * We should -EINVAL if an element length is not >= 0 and fitting an
+         * ssize_t.  The total length is fitting an ssize_t
+         *
+         * Be careful here because iov_len is a size_t not an ssize_t
+         */
+        tot_len = 0;
+        ret = -EINVAL;
+        for (seg = 0; seg < nr_segs; seg++) {
+                void __user *buf = iov[seg].iov_base;
+                ssize_t len = (ssize_t)iov[seg].iov_len;
+
+                if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
+                        goto Efault;
+                if (len < 0)    /* size_t not fitting an ssize_t .. */
+                        goto out;
+                tot_len += len;
+                if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
+                        goto out;
+        }
+        if (tot_len == 0) {
+                ret = 0;
+                goto out;
+        }
+
+        ret = rw_verify_area(type, file, pos, tot_len);
+        if (ret)
+                goto out;
+
+        fnv = NULL;
+        if (type == READ) {
+                fn = file->f_op->read;
+                fnv = file->f_op->readv;
+        } else {
+                fn = (io_fn_t)file->f_op->write;
+                fnv = file->f_op->writev;
+        }
+        if (fnv) {
+                ret = fnv(file, iov, nr_segs, pos);
+                goto out;
+        }
+
+        /* Do it by hand, with file-ops */
+        ret = 0;
+        vector = iov;
+        while (nr_segs > 0) {
+                void __user * base;
+                size_t len;
+                ssize_t nr;
+
+                base = vector->iov_base;
+                len = vector->iov_len;
+                vector++;
+                nr_segs--;
+
+                nr = fn(file, base, len, pos);
+
+                if (nr < 0) {
+                        if (!ret) ret = nr;
+                        break;
+                }
+                ret += nr;
+                if (nr != len)
+                        break;
+        }
+out:
+        if (iov != iovstack)
+                kfree(iov);
+        if ((ret + (type == READ)) > 0)
+                dnotify_parent(file->f_dentry,
+                                (type == READ) ? DN_ACCESS : DN_MODIFY);
+        return ret;
+Efault:
+        ret = -EFAULT;
+        goto out;
+}
+
+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_op || (!file->f_op->readv && !file->f_op->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_op || (!file->f_op->writev && !file->f_op->write))
+                return -EINVAL;
+
+        return do_readv_writev(WRITE, file, vec, vlen, pos);
+}
+
+EXPORT_SYMBOL(vfs_writev);
+
+asmlinkage ssize_t
+sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
+{
+        struct file *file;
+        ssize_t ret = -EBADF;
+        int fput_needed;
+
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                loff_t pos = file_pos_read(file);
+                ret = vfs_readv(file, vec, vlen, &pos);
+                file_pos_write(file, pos);
+                fput_light(file, fput_needed);
+        }
+
+        if (ret > 0)
+                current->rchar += ret;
+        current->syscr++;
+        return ret;
+}
+
+asmlinkage ssize_t
+sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
+{
+        struct file *file;
+        ssize_t ret = -EBADF;
+        int fput_needed;
+
+        file = fget_light(fd, &fput_needed);
+        if (file) {
+                loff_t pos = file_pos_read(file);
+                ret = vfs_writev(file, vec, vlen, &pos);
+                file_pos_write(file, pos);
+                fput_light(file, fput_needed);
+        }
+
+        if (ret > 0)
+                current->wchar += ret;
+        current->syscw++;
+        return ret;
+}
+
+static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
+                           size_t count, loff_t max)
+{
+        struct file * in_file, * out_file;
+        struct inode * in_inode, * out_inode;
+        loff_t pos;
+        ssize_t retval;
+        int fput_needed_in, fput_needed_out;
+
+        /*
+         * Get input file, and verify that it is ok..
+         */
+        retval = -EBADF;
+        in_file = fget_light(in_fd, &fput_needed_in);
+        if (!in_file)
+                goto out;
+        if (!(in_file->f_mode & FMODE_READ))
+                goto fput_in;
+        retval = -EINVAL;
+        in_inode = in_file->f_dentry->d_inode;
+        if (!in_inode)
+                goto fput_in;
+        if (!in_file->f_op || !in_file->f_op->sendfile)
+                goto fput_in;
+        retval = -ESPIPE;
+        if (!ppos)
+                ppos = &in_file->f_pos;
+        else
+                if (!(in_file->f_mode & FMODE_PREAD))
+                        goto fput_in;
+        retval = rw_verify_area(READ, in_file, ppos, count);
+        if (retval)
+                goto fput_in;
+
+        retval = security_file_permission (in_file, MAY_READ);
+        if (retval)
+                goto fput_in;
+
+        /*
+         * Get output file, and verify that it is ok..
+         */
+        retval = -EBADF;
+        out_file = fget_light(out_fd, &fput_needed_out);
+        if (!out_file)
+                goto fput_in;
+        if (!(out_file->f_mode & FMODE_WRITE))
+                goto fput_out;
+        retval = -EINVAL;
+        if (!out_file->f_op || !out_file->f_op->sendpage)
+                goto fput_out;
+        out_inode = out_file->f_dentry->d_inode;
+        retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
+        if (retval)
+                goto fput_out;
+
+        retval = security_file_permission (out_file, MAY_WRITE);
+        if (retval)
+                goto fput_out;
+
+        if (!max)
+                max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
+
+        pos = *ppos;
+        retval = -EINVAL;
+        if (unlikely(pos < 0))
+                goto fput_out;
+        if (unlikely(pos + count > max)) {
+                retval = -EOVERFLOW;
+                if (pos >= max)
+                        goto fput_out;
+                count = max - pos;
+        }
+
+        retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
+
+        if (retval > 0) {
+                current->rchar += retval;
+                current->wchar += retval;
+        }
+        current->syscr++;
+        current->syscw++;
+
+        if (*ppos > max)
+                retval = -EOVERFLOW;
+
+fput_out:
+        fput_light(out_file, fput_needed_out);
+fput_in:
+        fput_light(in_file, fput_needed_in);
+out:
+        return retval;
+}
+
+asmlinkage ssize_t sys_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);
+}
+
+asmlinkage ssize_t sys_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);
+}