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#include "fs/file.h"
#include "kernel/spinlock.h"
#include "kernel/mm.h"
#include "drivers/uart.h"
#include "kernel/proc.h"
#define NFILE 100
#define SEEK_SET 0
#define SEEK_CUR 1
#define SEEK_END 2
namespace FileTable
{
struct
{
Spinlock lock;
struct file files[NFILE];
} ftable;
void init()
{
ftable.lock.init("file_table");
}
struct file *alloc()
{
struct file *f;
ftable.lock.acquire();
for (f = ftable.files; f < ftable.files + NFILE; f++)
{
if (f->ref == 0)
{
f->ref = 1;
ftable.lock.release();
return f;
}
}
ftable.lock.release();
return nullptr;
}
struct file *dup(struct file *f)
{
ftable.lock.acquire();
if (f->ref < 1)
{
Drivers::uart_puts("panic: file dup\n");
while (1)
;
}
f->ref++;
ftable.lock.release();
return f;
}
void close(struct file *f)
{
struct file ff;
ftable.lock.acquire();
if(f->ref < 1)
{
Drivers::uart_puts("panic: file close\n");
while (1)
;
}
f->ref--;
if (f->ref > 0)
{
ftable.lock.release();
return;
}
ff = *f;
f->ref = 0;
f->type = FD_NONE;
ftable.lock.release();
if (ff.type == FD_INODE)
{
// Release the corresponding Inode
VFS::iput(ff.ip);
}
else if (ff.type == FD_PIPE)
{
// pipeclose(ff.pipe, ff.writable);
}
}
int read(struct file *f, uint64 addr, int n)
{
if (f->readable == 0)
return -1;
if (f->type == FD_INODE)
{
VFS::ilock(f->ip);
int r = f->ip->read((char*)addr, f->off, n, 1);
if(r > 0)
{
f->off += r;
}
VFS::iunlock(f->ip);
return r;
}
return -1;
}
int write(struct file *f, uint64 addr, int n)
{
if (f->writable == 0)
return -1;
if (f->type == FD_INODE)
{
VFS::ilock(f->ip);
int r = f->ip->write((char *)addr, f->off, n, 1);
if (r > 0)
{
f->off += r;
}
VFS::iunlock(f->ip);
return r;
}
// else if (f->type == FD_PIPE) ...
return -1;
}
int stat(struct file *f, uint64 addr)
{
if (f->type == FD_INODE)
{
struct kstat st;
VFS::ilock(f->ip);
f->ip->getattr(&st);
VFS::iunlock(f->ip);
struct Proc *p = myproc();
if (VM::copyout(p->pagetable, addr, (char *)&st, sizeof(st)) < 0)
return -1;
return 0;
}
return -1;
}
int lseek(struct file *f, int offset, int whence)
{
if (f->type != FD_INODE)
return -1;
VFS::ilock(f->ip);
int new_off = f->off;
int size = f->ip->size;
switch (whence)
{
case SEEK_SET:
new_off = offset;
break;
case SEEK_CUR:
new_off += offset;
break;
case SEEK_END:
new_off = size + offset;
break;
default:
VFS::iunlock(f->ip);
return -1;
}
if (new_off < 0)
{
VFS::iunlock(f->ip);
return -1;
}
f->off = new_off;
VFS::iunlock(f->ip);
return new_off;
}
} // namespace FileTable
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