/*
* sys_fstat
*/
int
sys_fstat(int fd, userptr_t statptr)
{
DEBUG(DB_VFS, "fstat %d\n", fd);
struct stat kbuf;
int err;
/* Check if fd is a valid file descriptor. */
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;
}
/* Call VOP_STAT on the vnode */
err = VOP_STAT(ft->ft_entries[fd]->ft_vnode, &kbuf);
spinlock_release(&ft->ft_spinlock);
if (err) {
return err;
}
return copyout(&kbuf, statptr, sizeof(struct stat));
}
void swap_init() {
int ret = vfs_open((char*) SWAP_DISK_NAME, O_RDWR, 0, &swap_vnode);
if (ret) {
kprintf("WARN swap disk not found Ret = %d\n", ret);
swap_state = SWAP_STATE_NOSWAP;
return;
}
struct stat statbuf;
ret = VOP_STAT(swap_vnode, &statbuf);
if (ret) {
kprintf("ERR Stat on swap disk failed\n");
swap_state = SWAP_STATE_NOSWAP;
return;
}
swap_page_count = (statbuf.st_size / PAGE_SIZE) - 1;
swap_map = (struct swap_entry*) kmalloc(
sizeof(struct swap_entry) * swap_page_count);
int i;
for (i = 0; i < swap_page_count; i++) {
swap_map[i].se_used = SWAP_PAGE_FREE;
swap_map[i].se_paddr = i;
}
swap_lock = lock_create("swap_lock");
swap_state = SWAP_STATE_READY;
kprintf("Swap init done. Total available pages = %d\n", swap_page_count);
}
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;
}
/*
* swap_bootstrap: Initializes swap information and finishes
* bootstrapping the VM so that processes can use it.
*
* Synchronization: none (runs during boot before anyone else uses VM)
*/
void
swap_bootstrap(size_t pmemsize)
{
int rv;
struct stat st;
char path[sizeof(swapfilename)];
off_t minsize;
strcpy(path, swapfilename);
rv = vfs_open(path, O_RDWR, &swapstore);
if (rv) {
kprintf("swap: Error %d opening swapfile %s\n", rv,
swapfilename);
kprintf("swap: Please create swapfile/swapdisk.\n");
panic("swap: Unable to continue.\n");
}
minsize = pmemsize*10;
VOP_STAT(swapstore, &st);
if (st.st_size < minsize) {
kprintf("swap: swapfile %s is only %lu bytes.\n", swapfilename,
(unsigned long) st.st_size);
kprintf("swap: with %lu bytes of physical memory it should "
"be at least\n", (unsigned long) pmemsize);
kprintf(" %lu bytes (%lu blocks).\n",
(unsigned long) minsize,
(unsigned long) minsize / 512);
kprintf("swap: Please extend it.\n");
panic("swap: Unable to continue.\n");
}
kprintf("swap: swapping to %s (%lu bytes; %lu pages)\n", swapfilename,
(unsigned long) st.st_size,
(unsigned long) st.st_size / PAGE_SIZE);
swap_total_pages = st.st_size / PAGE_SIZE;
swap_free_pages = swap_total_pages;
swap_reserved_pages = 0;
swapmap = bitmap_create(st.st_size/PAGE_SIZE);
DEBUG(DB_VM, "creating swap map with %d entries\n",
st.st_size/PAGE_SIZE);
if (swapmap == NULL) {
panic("swap: No memory for swap bitmap\n");
}
swaplock = lock_create("swaplock");
if (swaplock == NULL) {
panic("swap: No memory for swap lock\n");
}
/* mark the first page of swap used so we can check for errors */
bitmap_mark(swapmap, 0);
swap_free_pages--;
}
static
bool
swap_device_suficient( size_t ram_size, size_t *swap_size ) {
size_t min_size;
struct stat stat;
min_size = ram_size * SWAP_MIN_FACTOR;
VOP_STAT( vn_sw, &stat );
*swap_size = stat.st_size;
return stat.st_size >= min_size;
}
int
sys_lseek(int fd, off_t pos, int whence, off_t *new_pos)
{
int err;
struct fd_file *file;
struct stat stat;
file = get_file_from_fd_table(curproc->p_fd_table, fd);
if (file == NULL) {
err = EBADF;
goto err1;
}
lock_acquire(file->fdf_lock);
if (!VOP_ISSEEKABLE(file->fdf_vnode)) {
err = ESPIPE;
goto err2;
}
switch (whence) {
case SEEK_SET:
*new_pos = pos;
break;
case SEEK_CUR:
*new_pos = file->fdf_offset + pos;
break;
case SEEK_END:
VOP_STAT(file->fdf_vnode, &stat);
*new_pos = stat.st_size + pos;
break;
default:
err = EINVAL;
goto err2;
}
if (*new_pos < 0) {
err = EINVAL;
goto err2;
}
file->fdf_offset = *new_pos;
lock_release(file->fdf_lock);
return 0;
err2:
lock_release(file->fdf_lock);
err1:
return err;
}
void coreswap_init() {
struct stat temp;
VOP_STAT(swap_file, &temp);
coreswap_size = temp.st_size/PAGE_SIZE;
swap_map = bitmap_create(coreswap_size);
coreswap = (struct page_table_entry*)kmalloc(coreswap_size * sizeof(struct page_table_entry));
int coreswap_start=0;
kprintf("COREMAP INIT: %d %d\n",coremap_start,coremap_size);
for(int i = 0; i < temp.st_size/PAGE_SIZE; i++) {
coreswap[i].paddr = (coreswap_start + (i * PAGE_SIZE));
}
kprintf("COREMAP INIT: %d %d\n",coremap_start,coremap_size);
}
/*
* 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;
}
void swap_bootstrap(void)
{
int retval;
struct stat a;
// struct vnode *swap_vnode;
retval = vfs_open(SWAP_DEVICE, O_RDWR, &swap_vnode);
if(retval)
{
panic("could not open swap device\n") ;
}
VOP_STAT(swap_vnode, &a);
swap_map = bitmapCreate(a.st_size / PAGE_SIZE);
if(swap_map == NULL)
{
panic("could not create swap map\n") ;
}
vfs_close(swap_vnode);
}
/*
* Initialize the swap area and the bitmap to describe the area. We steal memory
* from ram to store these data structures. Initialize each of the page's chunk
* address.
*/
void init_swaparea()
{
int i;
struct stat file_stat;
//read the size of the disk0 into file_stat
VOP_STAT(swap_fp, &file_stat);
//swaparea size is in PAGE_SIZE unit
swaparea_size = file_stat.st_size/PAGE_SIZE;
//bitmap to describe the swaparea (in memory or in disk)
swap_memmap = bitmap_create(swaparea_size);
//allocate the swaparea into memory by stealing some memory from RAM
swaparea = (struct _PTE*)kmalloc(swaparea_size * sizeof(struct _PTE));
//we are initializing swaparea first, so base address should be 0
swap_base = 0;
//set chunk of each of the pages in the swaparea
for(i = 0; i < file_stat.st_size/PAGE_SIZE; i++)
{
swaparea[i].paddr = (swap_base + (i * PAGE_SIZE));
}
}
/*
* sys_fstat
*/
int
sys_fstat(int fd, userptr_t statptr)
{
struct stat kstat;
int result;
struct filetable *file_table = curthread->t_filetable;
spinlock_acquire(&file_table->filetable_lock);
//kprintf(" doing fstat");
//check for fd is valid or not
if((fd > __OPEN_MAX) || (file_table->ft_entries[fd] == NULL) || (fd<0)){
spinlock_release(&file_table->filetable_lock);
return EBADF;
}
//use vop_stat to return the info of file
result = VOP_STAT(file_table->ft_entries[fd]->file_vnode, &kstat);
if(result){
return result;
}
spinlock_release(&file_table->filetable_lock);
//kprintf(" fstat done");
return copyout(&kstat, statptr, sizeof(struct stat));
}
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;
}
/* normal open() function - called by user */
int sys_open(const_userptr_t fileName, int flags, int * retval) {
char fileNameFromUser[BUF_SIZE]; // file name from copyinstr
bool append_flag = false; // if O_APPEND is one of the flags, this variable is set to TRUE
int err;
// Step 1: first check if the filename pointer is valid
if (fileName == NULL) {
err = EFAULT;
return err;
}
// Step 2: then check if the flags are valid (use switch statement to check for valid flags)
switch(flags) {
case O_RDONLY: break;
case O_WRONLY: break;
case O_RDWR: break;
case O_RDONLY|O_CREAT: break;
case O_WRONLY|O_CREAT: break;
case O_WRONLY|O_APPEND: append_flag = true;
break;
case O_RDWR|O_CREAT: break;
case O_RDWR|O_APPEND: append_flag = true;
break;
case O_RDWR|O_CREAT|O_TRUNC: break;
default: err = EINVAL;
return err;
}
// Step 3: if steps 1 and 2 are passing, then find an empty slot in the tfd_table and allocate it to this file that is going to be opened
int slot = -1;
for (int i=3; i<OPEN_MAX; i++) {
if (curthread->t_fdtable[i] == NULL) {
slot = i;
break;
}
}
/* in case the file table is full and there are no empty slots */
if (slot == -1) {
err = EMFILE;
return err;
}
// Step 4: copy the valid filename into the kernel buffer, using the copyinstr function
size_t actual;
if ((err = copyinstr(fileName, fileNameFromUser, BUF_SIZE, &actual)) != 0) {
return err;
}
// Step 5: call vfs_open, with correct arguments
struct vnode * node;
err = vfs_open(fileNameFromUser, flags, 0, &node);
// add code here to check if vnode returned successfully
if (err) { // if vnode not successful, then return appropriate error to user
return err;
}
// Step 6: initialize the struct fhandle with correct values, taking the flags into consideration
if (append_flag) { /* case where the APPEND flag is true, get the file size and set pass it as the offset */
struct stat buffer;
VOP_STAT(node, &buffer);
int bytes = buffer.st_size;
*retval = slot;
curthread->t_fdtable[slot] = fhandle_create(fileNameFromUser, flags, bytes, node);
KASSERT(curthread->t_fdtable[slot] != NULL);
} else { /* case where append flag is not TRUE */
*retval = slot;
curthread->t_fdtable[slot] = fhandle_create(fileNameFromUser, flags, 0, node);
KASSERT(curthread->t_fdtable[slot] != NULL);
}
/* on success, return 0 */
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;
}