133 lines
2.3 KiB
C
133 lines
2.3 KiB
C
#include "types.h"
|
|
#include "stat.h"
|
|
#include "param.h"
|
|
#include "x86.h"
|
|
#include "mmu.h"
|
|
#include "proc.h"
|
|
#include "defs.h"
|
|
#include "file.h"
|
|
#include "spinlock.h"
|
|
#include "dev.h"
|
|
#include "fs.h"
|
|
#include "fsvar.h"
|
|
|
|
struct devsw devsw[NDEV];
|
|
struct spinlock file_table_lock;
|
|
struct file file[NFILE];
|
|
|
|
void
|
|
fileinit(void)
|
|
{
|
|
initlock(&file_table_lock, "file_table");
|
|
}
|
|
|
|
// Allocate a file structure.
|
|
struct file*
|
|
filealloc(void)
|
|
{
|
|
int i;
|
|
|
|
acquire(&file_table_lock);
|
|
for(i = 0; i < NFILE; i++){
|
|
if(file[i].type == FD_CLOSED){
|
|
file[i].type = FD_NONE;
|
|
file[i].ref = 1;
|
|
release(&file_table_lock);
|
|
return file + i;
|
|
}
|
|
}
|
|
release(&file_table_lock);
|
|
return 0;
|
|
}
|
|
|
|
// Increment ref count for file f.
|
|
struct file*
|
|
filedup(struct file *f)
|
|
{
|
|
acquire(&file_table_lock);
|
|
if(f->ref < 1 || f->type == FD_CLOSED)
|
|
panic("filedup");
|
|
f->ref++;
|
|
release(&file_table_lock);
|
|
return f;
|
|
}
|
|
|
|
// Close file f. (Decrement ref count, close when reaches 0.)
|
|
void
|
|
fileclose(struct file *f)
|
|
{
|
|
struct file ff;
|
|
|
|
acquire(&file_table_lock);
|
|
if(f->ref < 1 || f->type == FD_CLOSED)
|
|
panic("fileclose");
|
|
if(--f->ref > 0){
|
|
release(&file_table_lock);
|
|
return;
|
|
}
|
|
ff = *f;
|
|
f->ref = 0;
|
|
f->type = FD_CLOSED;
|
|
release(&file_table_lock);
|
|
|
|
if(ff.type == FD_PIPE)
|
|
pipe_close(ff.pipe, ff.writable);
|
|
else if(ff.type == FD_INODE)
|
|
iput(ff.ip);
|
|
else
|
|
panic("fileclose");
|
|
}
|
|
|
|
// Get metadata about file f.
|
|
int
|
|
filestat(struct file *f, struct stat *st)
|
|
{
|
|
if(f->type == FD_INODE){
|
|
ilock(f->ip);
|
|
stati(f->ip, st);
|
|
iunlock(f->ip);
|
|
return 0;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
// Read from file f. Addr is kernel address.
|
|
int
|
|
fileread(struct file *f, char *addr, int n)
|
|
{
|
|
int r;
|
|
|
|
if(f->readable == 0)
|
|
return -1;
|
|
if(f->type == FD_PIPE)
|
|
return pipe_read(f->pipe, addr, n);
|
|
if(f->type == FD_INODE){
|
|
ilock(f->ip);
|
|
if((r = readi(f->ip, addr, f->off, n)) > 0)
|
|
f->off += r;
|
|
iunlock(f->ip);
|
|
return r;
|
|
}
|
|
panic("fileread");
|
|
}
|
|
|
|
// Write to file f. Addr is kernel address.
|
|
int
|
|
filewrite(struct file *f, char *addr, int n)
|
|
{
|
|
int r;
|
|
|
|
if(f->writable == 0)
|
|
return -1;
|
|
if(f->type == FD_PIPE)
|
|
return pipe_write(f->pipe, addr, n);
|
|
if(f->type == FD_INODE){
|
|
ilock(f->ip);
|
|
if((r = writei(f->ip, addr, f->off, n)) > 0)
|
|
f->off += r;
|
|
iunlock(f->ip);
|
|
return r;
|
|
}
|
|
panic("filewrite");
|
|
}
|
|
|