/*
* linux/fs/read_write.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/malloc.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 <asm/uaccess.h>
struct file_operations generic_ro_fops = {
read: generic_file_read,
mmap: generic_file_mmap,
};
22 ssize_t generic_read_dir(struct file *filp, char *buf, size_t siz, loff_t *ppos)
{
24 return -EISDIR;
}
27 loff_t default_llseek(struct file *file, loff_t offset, int origin)
{
long long retval;
31 switch (origin) {
32 case 2:
offset += file->f_dentry->d_inode->i_size;
34 break;
35 case 1:
offset += file->f_pos;
}
retval = -EINVAL;
39 if (offset >= 0) {
40 if (offset != file->f_pos) {
file->f_pos = offset;
file->f_reada = 0;
file->f_version = ++event;
}
retval = offset;
}
47 return retval;
}
50 static inline loff_t llseek(struct file *file, loff_t offset, int origin)
{
loff_t (*fn)(struct file *, loff_t, int);
loff_t retval;
fn = default_llseek;
56 if (file->f_op && file->f_op->llseek)
fn = file->f_op->llseek;
58 lock_kernel();
retval = fn(file, offset, origin);
60 unlock_kernel();
61 return retval;
}
64 asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
{
off_t retval;
struct file * file;
retval = -EBADF;
file = fget(fd);
71 if (!file)
72 goto bad;
retval = -EINVAL;
74 if (origin <= 2) {
loff_t res = llseek(file, offset, origin);
retval = res;
77 if (res != (loff_t)retval)
retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
}
fput(file);
bad:
82 return retval;
}
#if !defined(__alpha__)
86 asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
unsigned long offset_low, loff_t * result,
unsigned int origin)
{
int retval;
struct file * file;
loff_t offset;
retval = -EBADF;
file = fget(fd);
96 if (!file)
97 goto bad;
retval = -EINVAL;
99 if (origin > 2)
100 goto out_putf;
offset = llseek(file, ((loff_t) offset_high << 32) | offset_low,
origin);
retval = (int)offset;
106 if (offset >= 0) {
retval = -EFAULT;
108 if (!copy_to_user(result, &offset, sizeof(offset)))
retval = 0;
}
out_putf:
fput(file);
bad:
114 return retval;
}
#endif
118 asmlinkage ssize_t sys_read(unsigned int fd, char * buf, size_t count)
{
ssize_t ret;
struct file * file;
ret = -EBADF;
file = fget(fd);
125 if (file) {
126 if (file->f_mode & FMODE_READ) {
ret = locks_verify_area(FLOCK_VERIFY_READ, file->f_dentry->d_inode,
file, file->f_pos, count);
129 if (!ret) {
ssize_t (*read)(struct file *, char *, size_t, loff_t *);
ret = -EINVAL;
132 if (file->f_op && (read = file->f_op->read) != NULL)
ret = read(file, buf, count, &file->f_pos);
}
}
136 if (ret > 0)
inode_dir_notify(file->f_dentry->d_parent->d_inode,
DN_ACCESS);
fput(file);
}
141 return ret;
}
144 asmlinkage ssize_t sys_write(unsigned int fd, const char * buf, size_t count)
{
ssize_t ret;
struct file * file;
ret = -EBADF;
file = fget(fd);
151 if (file) {
152 if (file->f_mode & FMODE_WRITE) {
struct inode *inode = file->f_dentry->d_inode;
ret = locks_verify_area(FLOCK_VERIFY_WRITE, inode, file,
file->f_pos, count);
156 if (!ret) {
ssize_t (*write)(struct file *, const char *, size_t, loff_t *);
ret = -EINVAL;
159 if (file->f_op && (write = file->f_op->write) != NULL)
ret = write(file, buf, count, &file->f_pos);
}
}
163 if (ret > 0)
inode_dir_notify(file->f_dentry->d_parent->d_inode,
DN_MODIFY);
fput(file);
}
168 return ret;
}
172 static ssize_t do_readv_writev(int type, struct file *file,
const struct iovec * vector,
unsigned long count)
{
typedef ssize_t (*io_fn_t)(struct file *, char *, 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;
ssize_t ret, i;
io_fn_t fn;
iov_fn_t fnv;
struct inode *inode;
/*
* First get the "struct iovec" from user memory and
* verify all the pointers
*/
ret = 0;
192 if (!count)
193 goto out_nofree;
ret = -EINVAL;
195 if (count > UIO_MAXIOV)
196 goto out_nofree;
197 if (!file->f_op)
198 goto out_nofree;
199 if (count > UIO_FASTIOV) {
ret = -ENOMEM;
iov = kmalloc(count*sizeof(struct iovec), GFP_KERNEL);
202 if (!iov)
203 goto out_nofree;
}
ret = -EFAULT;
206 if (copy_from_user(iov, vector, count*sizeof(*vector)))
207 goto out;
/* BSD readv/writev returns EINVAL if one of the iov_len
values < 0 or tot_len overflowed a 32-bit integer. -ink */
tot_len = 0;
ret = -EINVAL;
213 for (i = 0 ; i < count ; i++) {
size_t tmp = tot_len;
int len = iov[i].iov_len;
216 if (len < 0)
217 goto out;
(u32)tot_len += len;
219 if (tot_len < tmp || tot_len < (u32)len)
220 goto out;
}
inode = file->f_dentry->d_inode;
/* VERIFY_WRITE actually means a read, as we write to user space */
ret = locks_verify_area((type == VERIFY_WRITE
? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE),
inode, file, file->f_pos, tot_len);
228 if (ret) goto out;
fnv = (type == VERIFY_WRITE ? file->f_op->readv : file->f_op->writev);
231 if (fnv) {
ret = fnv(file, iov, count, &file->f_pos);
233 goto out;
}
/* VERIFY_WRITE actually means a read, as we write to user space */
fn = (type == VERIFY_WRITE ? file->f_op->read :
(io_fn_t) file->f_op->write);
ret = 0;
vector = iov;
242 while (count > 0) {
void * base;
size_t len;
ssize_t nr;
base = vector->iov_base;
len = vector->iov_len;
vector++;
count--;
nr = fn(file, base, len, &file->f_pos);
254 if (nr < 0) {
255 if (!ret) ret = nr;
256 break;
}
ret += nr;
259 if (nr != len)
260 break;
}
out:
264 if (iov != iovstack)
kfree(iov);
out_nofree:
/* VERIFY_WRITE actually means a read, as we write to user space */
268 if ((ret + (type == VERIFY_WRITE)) > 0)
inode_dir_notify(file->f_dentry->d_parent->d_inode,
(type == VERIFY_WRITE) ? DN_MODIFY : DN_ACCESS);
271 return ret;
}
274 asmlinkage ssize_t sys_readv(unsigned long fd, const struct iovec * vector,
unsigned long count)
{
struct file * file;
ssize_t ret;
ret = -EBADF;
file = fget(fd);
283 if (!file)
284 goto bad_file;
if (file->f_op && (file->f_mode & FMODE_READ) &&
286 (file->f_op->readv || file->f_op->read))
ret = do_readv_writev(VERIFY_WRITE, file, vector, count);
fput(file);
bad_file:
291 return ret;
}
294 asmlinkage ssize_t sys_writev(unsigned long fd, const struct iovec * vector,
unsigned long count)
{
struct file * file;
ssize_t ret;
ret = -EBADF;
file = fget(fd);
303 if (!file)
304 goto bad_file;
if (file->f_op && (file->f_mode & FMODE_WRITE) &&
306 (file->f_op->writev || file->f_op->write))
ret = do_readv_writev(VERIFY_READ, file, vector, count);
fput(file);
bad_file:
311 return ret;
}
/* From the Single Unix Spec: pread & pwrite act like lseek to pos + op +
lseek back to original location. They fail just like lseek does on
non-seekable files. */
318 asmlinkage ssize_t sys_pread(unsigned int fd, char * buf,
size_t count, loff_t pos)
{
ssize_t ret;
struct file * file;
ssize_t (*read)(struct file *, char *, size_t, loff_t *);
ret = -EBADF;
file = fget(fd);
327 if (!file)
328 goto bad_file;
329 if (!(file->f_mode & FMODE_READ))
330 goto out;
ret = locks_verify_area(FLOCK_VERIFY_READ, file->f_dentry->d_inode,
file, pos, count);
333 if (ret)
334 goto out;
ret = -EINVAL;
336 if (!file->f_op || !(read = file->f_op->read))
337 goto out;
338 if (pos < 0)
339 goto out;
ret = read(file, buf, count, &pos);
341 if (ret > 0)
inode_dir_notify(file->f_dentry->d_parent->d_inode, DN_ACCESS);
out:
fput(file);
bad_file:
346 return ret;
}
349 asmlinkage ssize_t sys_pwrite(unsigned int fd, const char * buf,
size_t count, loff_t pos)
{
ssize_t ret;
struct file * file;
ssize_t (*write)(struct file *, const char *, size_t, loff_t *);
ret = -EBADF;
file = fget(fd);
358 if (!file)
359 goto bad_file;
360 if (!(file->f_mode & FMODE_WRITE))
361 goto out;
ret = locks_verify_area(FLOCK_VERIFY_WRITE, file->f_dentry->d_inode,
file, pos, count);
364 if (ret)
365 goto out;
ret = -EINVAL;
367 if (!file->f_op || !(write = file->f_op->write))
368 goto out;
369 if (pos < 0)
370 goto out;
ret = write(file, buf, count, &pos);
373 if (ret > 0)
inode_dir_notify(file->f_dentry->d_parent->d_inode, DN_MODIFY);
out:
fput(file);
bad_file:
378 return ret;
}