151 lines
2.5 KiB
C
151 lines
2.5 KiB
C
#include "types.h"
|
|
#include "stat.h"
|
|
#include "param.h"
|
|
#include "x86.h"
|
|
#include "mmu.h"
|
|
#include "proc.h"
|
|
#include "defs.h"
|
|
#include "fd.h"
|
|
#include "spinlock.h"
|
|
#include "dev.h"
|
|
#include "fs.h"
|
|
#include "fsvar.h"
|
|
|
|
struct spinlock fd_table_lock;
|
|
struct devsw devsw[NDEV];
|
|
|
|
struct fd fds[NFD];
|
|
|
|
void
|
|
fd_init(void)
|
|
{
|
|
initlock(&fd_table_lock, "fd_table");
|
|
}
|
|
|
|
/*
|
|
* allocate a file descriptor number for curproc.
|
|
*/
|
|
int
|
|
fd_ualloc(void)
|
|
{
|
|
int fd;
|
|
struct proc *p = curproc[cpu()];
|
|
for(fd = 0; fd < NOFILE; fd++)
|
|
if(p->fds[fd] == 0)
|
|
return fd;
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* allocate a file descriptor structure
|
|
*/
|
|
struct fd *
|
|
fd_alloc(void)
|
|
{
|
|
int i;
|
|
|
|
acquire(&fd_table_lock);
|
|
for(i = 0; i < NFD; i++){
|
|
if(fds[i].type == FD_CLOSED){
|
|
fds[i].type = FD_NONE;
|
|
fds[i].ref = 1;
|
|
release(&fd_table_lock);
|
|
return fds + i;
|
|
}
|
|
}
|
|
release(&fd_table_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* addr is a kernel address, pointing into some process's p->mem.
|
|
*/
|
|
int
|
|
fd_write(struct fd *fd, char *addr, int n)
|
|
{
|
|
if(fd->writeable == 0)
|
|
return -1;
|
|
if(fd->type == FD_PIPE){
|
|
return pipe_write(fd->pipe, addr, n);
|
|
} else if (fd->type == FD_FILE) {
|
|
ilock(fd->ip);
|
|
int r = writei (fd->ip, addr, fd->off, n);
|
|
if (r > 0) {
|
|
fd->off += r;
|
|
}
|
|
iunlock(fd->ip);
|
|
return r;
|
|
} else {
|
|
panic("fd_write");
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
int
|
|
fd_read(struct fd *fd, char *addr, int n)
|
|
{
|
|
if(fd->readable == 0)
|
|
return -1;
|
|
if(fd->type == FD_PIPE){
|
|
return pipe_read(fd->pipe, addr, n);
|
|
} else if(fd->type == FD_FILE){
|
|
ilock(fd->ip);
|
|
int cc = readi(fd->ip, addr, fd->off, n);
|
|
if(cc > 0)
|
|
fd->off += cc;
|
|
iunlock(fd->ip);
|
|
return cc;
|
|
} else {
|
|
panic("fd_read");
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
void
|
|
fd_close(struct fd *fd)
|
|
{
|
|
acquire(&fd_table_lock);
|
|
|
|
if(fd->ref < 1 || fd->type == FD_CLOSED)
|
|
panic("fd_close");
|
|
|
|
if(--fd->ref == 0){
|
|
struct fd dummy = *fd;
|
|
|
|
fd->ref = 0;
|
|
fd->type = FD_CLOSED;
|
|
release(&fd_table_lock);
|
|
|
|
if(dummy.type == FD_PIPE){
|
|
pipe_close(dummy.pipe, dummy.writeable);
|
|
} else if(dummy.type == FD_FILE){
|
|
idecref(dummy.ip);
|
|
} else {
|
|
panic("fd_close");
|
|
}
|
|
} else {
|
|
release(&fd_table_lock);
|
|
}
|
|
}
|
|
|
|
int
|
|
fd_stat(struct fd *fd, struct stat *st)
|
|
{
|
|
if(fd->type == FD_FILE){
|
|
ilock(fd->ip);
|
|
stati(fd->ip, st);
|
|
iunlock(fd->ip);
|
|
return 0;
|
|
} else
|
|
return -1;
|
|
}
|
|
|
|
void
|
|
fd_incref(struct fd *fd)
|
|
{
|
|
acquire(&fd_table_lock);
|
|
if(fd->ref < 1 || fd->type == FD_CLOSED)
|
|
panic("fd_incref");
|
|
fd->ref++;
|
|
release(&fd_table_lock);
|
|
}
|