int sys_readdir(unsigned int fd, char *dirent, unsigned int count
/* ignored and unused, noted in Linux man page */ )
{
int error;
struct file *file;
register struct file *filp;
register struct file_operations *fop;
struct readdir_callback buf;
if ((error = fd_check(fd, dirent, sizeof(struct linux_dirent),
FMODE_READ, &file))
>= 0) {
error = -ENOTDIR;
filp = file;
fop = filp->f_op;
if (fop && fop->readdir) {
buf.count = 0;
buf.dirent = (struct linux_dirent *) dirent;
if ((error = fop->readdir(filp->f_inode, filp,
&buf, fillonedir))
>= 0)
return buf.count;
}
}
return error;
}
int sys_read(unsigned int fd, char *buf, size_t count)
{
register struct file_operations *fop;
struct file *file;
int retval;
if (((retval = fd_check(fd, buf, count, FMODE_READ, &file)) == 0)
&& count) {
retval = -EINVAL;
fop = file->f_op;
if (fop->read) {
retval = (int) fop->read(file->f_inode, file, buf, count);
schedule();
}
}
return retval;
}
int sys_write(unsigned int fd, char *buf, size_t count)
{
register struct file_operations *fop;
struct file *file;
register struct inode *inode;
int written;
if (((written = fd_check(fd, buf, count, FMODE_WRITE, &file)) == 0)
&& (count != 0)) {
written = -EINVAL;
fop = file->f_op;
if (fop->write) {
inode = file->f_inode;
/*
* If data has been written to the file, remove the setuid and
* the setgid bits. We do it anyway otherwise there is an
* extremely exploitable race - does your OS get it right |->
*
* Set ATTR_FORCE so it will always be changed.
*/
if (!suser() && (inode->i_mode & (S_ISUID | S_ISGID))) {
#ifdef USE_NOTIFY_CHANGE
struct iattr newattrs;
newattrs.ia_mode = inode->i_mode & ~(S_ISUID | S_ISGID);
newattrs.ia_valid = ATTR_CTIME | ATTR_MODE | ATTR_FORCE;
notify_change(inode, &newattrs);
#else
inode->i_mode = inode->i_mode & ~(S_ISUID | S_ISGID);
#endif
}
written = (int) fop->write(inode, file, buf, count);
schedule();
}
}
return written;
}
