off_t
lseek(int fd,off_t pos, int whence,int *err)
{
off_t nPos=0;
struct stat eoFILE;
//kprintf("lseek entered\n");
if ( fd < 0 || fd > OPEN_MAX)
{
*err = EBADF;
return -1;
}
if (curthread->ft[fd] == NULL)
{
*err = EBADF;
return -1;
}
//kprintf("curthread->ft[fd] == NULL\n");
//kprintf("fd < 0 || fd > OPEN_MAX\n");
if (whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END)
{
*err = EINVAL;
return -1;
}
//kprintf("whence != SEEK_SET || whence != SEEK_CUR || whence != SEEK_END\n");
//kprintf("Acquiring lock\n");
lock_acquire(curthread->ft[fd]->lock);
//kprintf("Stat gathering\n");
VOP_STAT(curthread->ft[fd]->vn,&eoFILE);
if (whence == SEEK_SET)
{
nPos = pos;
}
if (whence == SEEK_CUR)
{
nPos = curthread->ft[fd]->offset+pos;
}
if (whence == SEEK_END)
{
nPos = eoFILE.st_size+pos;
}
if (nPos < 0)
{
*err = EINVAL;
lock_release(curthread->ft[fd]->lock);
return -1;
}
//kprintf("NPos %llu\n",nPos);
*err = VOP_TRYSEEK(curthread->ft[fd]->vn,nPos);
if (*err)
{
lock_release(curthread->ft[fd]->lock);
return -1;
}
curthread->ft[fd]->offset = nPos;
lock_release(curthread->ft[fd]->lock);
//kprintf("New position %llu\n",nPos);
return curthread->ft[fd]->offset;
}
/*
* sys_lseek
*
*/
int
sys_lseek(int fd, off_t offset, int whence, off_t *retval)
{
DEBUG(DB_VFS, "Lseeking fd %d with offset %d\n", fd, (int)offset);
struct filetable *ft = curthread->t_filetable;
spinlock_acquire(&ft->ft_spinlock);
/* If fd is not a valid file descriptor, return error. */
if ((fd < 0) || (fd >= __OPEN_MAX) || (ft->ft_entries[fd] == NULL) ||
(ft->ft_entries[fd]->ft_vnode == NULL)) {
spinlock_release(&ft->ft_spinlock);
return EBADF;
}
int pos;
if (whence == SEEK_SET) {
/* Update new position to offset.*/
pos = (int)offset;
}
else if (whence == SEEK_CUR) {
/* Update new position to current position + pos. */
pos = (ft->ft_entries[fd]->ft_pos + (int)offset);
} else if (whence == SEEK_END) {
/* Update new positionto end-of-file + pos. */
struct stat ft_stat;
VOP_STAT(ft->ft_entries[fd]->ft_vnode, &ft_stat);
pos = ft_stat.st_size + offset;
} else {
/* whence value is invalid. return error. */
spinlock_release(&ft->ft_spinlock);
return EINVAL;
}
/* If resulting position is negative, return error. */
if (pos < 0) {
spinlock_release(&ft->ft_spinlock);
return EINVAL;
}
int result = VOP_TRYSEEK(ft->ft_entries[fd]->ft_vnode, pos);
if (result != 0) {
DEBUG(DB_VFS, " tryseek failed with %d\n", result);
spinlock_release(&ft->ft_spinlock);
return ESPIPE;
}
ft->ft_entries[fd]->ft_pos = pos;
*retval = (off_t)pos;
spinlock_release(&ft->ft_spinlock);
return 0;
}
off_t
sys_lseek(int fd,off_t pos, int whence, int *err){
if (whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END){
*err = EINVAL;
return -1;
}
if (fd < 0 || fd >= MAX_FILE_DESCRIPTOR){
*err = EBADF;
return -1;
}
if (curthread->fd[fd] == NULL){
*err = EBADF;
return -1;
}
lock_acquire(curthread->fd[fd]->mutex);
if (curthread->fd[fd]->update_pos == 0){
*err = ESPIPE;
lock_release(curthread->fd[fd]->mutex);
return -1;
}
off_t newpos;
struct stat stat;
VOP_STAT(curthread->fd[fd]->file,&stat);
if (whence == SEEK_SET)
newpos = pos;
if (whence == SEEK_CUR)
newpos = curthread->fd[fd]->offset+pos;
if (whence == SEEK_END)
newpos = stat.st_size+pos;
if (newpos < 0){
*err = EINVAL;
lock_release(curthread->fd[fd]->mutex);
return -1;
}
*err = VOP_TRYSEEK(curthread->fd[fd]->file,newpos);
if (*err){
lock_release(curthread->fd[fd]->mutex);
return -1;
}
curthread->fd[fd]->offset = newpos;
lock_release(curthread->fd[fd]->mutex);
return curthread->fd[fd]->offset;
}
int sys_lseek(int filehandle, off_t pos, int code, int *retval)
{
off_t newfp;
int r;
struct stat statbuf;
/* check file handle */
r = check_fd_access(filehandle, curthread->t_fdt, F_ANY);
if (r) return r;
switch (code) {
case SEEK_SET:
newfp = pos;
break;
case SEEK_CUR:
newfp = curthread->t_fdt->fd[filehandle]->fp + pos;
break;
case SEEK_END:
r = VOP_STAT(curthread->t_fdt->fd[filehandle]->vn, &statbuf);
if (r) return r;
newfp = statbuf.st_size + pos;
break;
default:
return EINVAL;
}
if (newfp < 0) {
return EINVAL;
}
r = VOP_TRYSEEK(curthread->t_fdt->fd[filehandle]->vn, newfp);
if (r < 0) {
return r;
}
curthread->t_fdt->fd[filehandle]->fp = newfp;
*retval = newfp;
return 0;
}
int sys_lseek(int fid, off_t offset, int whence, int* retval) {
struct openfile* seekfile = (struct openfile*)array_getguy(curthread->t_openfiletable,fid);
if (seekfile == NULL) {
return EBADF;
}
if (whence == SEEK_SET) {
offset = offset;
} else if(whence == SEEK_CUR) {
offset = seekfile->offset + offset;
} else if (whence == SEEK_END) {
//end of file plus offset
} else {
return EINVAL;
}
*retval = VOP_TRYSEEK(seekfile->data,offset);
if (*retval < 0) {
return EINVAL;
}
return 0;
}
/* lseek() call handler */
int sys_lseek(int fd, off_t pos, int whence, off_t * retVal64){
int err;
off_t currentPosition;
off_t endPosition;
off_t posSeek;
struct stat buffer;
/* Step 1: Check if the file descriptor passed in is valid */
if (fd >= OPEN_MAX || fd < 0) { // fd is out of bounds of the file table
return EBADF;
}
struct fhandle * fdesc = curthread->t_fdtable[fd];
if (fdesc == NULL) {
return EBADF;
}
/* Adding locks to synchronize the whole process */
lock_acquire(fdesc->lock);
switch(whence) { // logic for different cases
case SEEK_SET: //VOP_TRYSEEK(vnode, position)
if (pos < 0) {
lock_release(fdesc->lock);
return EINVAL; // seek position is negative
}
posSeek = pos;
if ((err = VOP_TRYSEEK(fdesc->vn, posSeek)) != 0) {
lock_release(fdesc->lock);
return ESPIPE; // in case the SEEK fails
}
fdesc->offset = posSeek;
*retVal64 = fdesc->offset;
break;
case SEEK_CUR: currentPosition = fdesc->offset;
posSeek = currentPosition + pos;
if (posSeek < 0) {
lock_release(fdesc->lock);
return EINVAL;
}
if ((err = VOP_TRYSEEK(fdesc->vn, posSeek)) != 0) {
lock_release(fdesc->lock);
return ESPIPE;
}
fdesc->offset = posSeek;
*retVal64 = fdesc->offset;
break;
case SEEK_END: VOP_STAT(fdesc->vn, &buffer);
endPosition = buffer.st_size;
posSeek = endPosition + pos;
if (posSeek < 0) {
lock_release(fdesc->lock);
return EINVAL;
}
if ((err = VOP_TRYSEEK(fdesc->vn, posSeek)) != 0) {
lock_release(fdesc->lock);
return ESPIPE;
}
if (pos < 0) {
fdesc->offset = posSeek + pos;
} else {
fdesc->offset = posSeek;
}
*retVal64 = fdesc->offset;
break;
default:
return EINVAL;
}
lock_release(fdesc->lock);
return 0;
}
