int write_pipe(int fd, char *buf, int n)
{
// your code for write_pipe()
PIPE *pipe;
char * offset;
int wbytes = 0;
u8 byte;
offset = buf;
pipe = running->fd[fd]->pipe_ptr;
if(running->fd[fd] ==0){
printf("Error: fd is not open\n");
return -1;
}
if(running->fd[fd]->mode != WRITE_PIPE){
printf("Error: fd mode is not write\n");
return -2;
}
printf("BEFORE WRITE:\n");
show_pipe(pipe);
while(wbytes < n){
if(pipe->nreader == 0){
printf("NO READER\n");
return BROKEN_PIPE_ERROR;
}else{
if(pipe->room != 0){
byte = get_byte(running->uss, offset);
printf("WRITE BYTE: %c[%d]\n", byte, pipe->head);
pipe->buf[pipe->head] = byte;
pipe->head++;
offset++;
wbytes++;
pipe->room--;
pipe->data++;
pipe->head %= PIPE_SIZE;
kwakeup(&(pipe->data));
}else{
kwakeup(&(pipe->data));
ksleep(&(pipe->room));
}
}
}
printf("AFTER WRITE:\n");
show_pipe(pipe);
return wbytes;
}
int read_pipe(int fd, char *buf, int n)
{
int r = 0;
char c;
OFT *op; PIPE *p;
if (n<=0) return 0;
if (fd < 0 || fd > NFD || running->fd[fd] == 0){
printf("bad fd %d\n", fd);
return -1;
}
op = running->fd[fd];
if (op->mode != READ_PIPE){
printf("fd = %d is NOT for read\n", fd);
return -1;
}
p = op->pipe_ptr;
printf("pipe before reading\n");
show_pipe(p);
while(n){
while(p->data){
c = p->buf[p->tail++];
put_byte(c, running->uss, buf);
p->tail %= PSIZE;
p->data--; p->room++;
n--; r++; buf++;
if (n == 0) break;
}
if (n==0 || r){
kwakeup(&p->room);
printf("pipe after reading\n");
show_pipe(p);
return r;
}
// pipe has no data
if (p->nwriter){ // if pipe still has writer
printf("pipe before reader goes to sleep\n");
show_pipe(p);
kwakeup(&p->room); // wakeup ALL writers, if any.
ksleep(&p->data); // sleep for data
continue;
}
// pipe has no writer and no data
return 0;
}
}
int write_pipe(int fd, char *buf, int n)
{
char c; int r=0;
PIPE *p; OFT *op;
if (fd < 0 || fd > NFD || running->fd[fd] == 0){
printf("bad fd %d\n", fd);
return -1;
}
op = running->fd[fd];
if (op->mode != WRITE_PIPE){
printf("fd = %d is NOT for write\n", fd);
return -1;
}
p = op->pipe_ptr;
printf("pipe before writing\n");
show_pipe(p);
while(n){
if (!p->nreader){ // no more readers
printf("proc %d : BROKEN_PIPE error\n", running->pid);
kexit(0x0D); // simulate SIGPIPE=13
}
while(p->room && n){
p->buf[p->head++] = get_byte(running->uss, buf);
p->head %= PSIZE;
p->data++; p->room--;
n--; r++; buf++;
}
kwakeup(&p->data); // wakeup ALL readers, if any.
if (n==0){
printf("pipe after writing\n");
show_pipe(p);
return r; // finished writing n bytes
}
// still has data to write but pipe has no room
printf("pipe before writer goes to sleep\n");
show_pipe(p);
ksleep(&p->room); // sleep for room
}
return r;
}
int read_pipe(int fd, char *buf, int n)
{
// your code for read_pipe()
PIPE *pipe;
char * offset;
int rbytes = 0;
u8 byte;
offset = buf;
pipe = running->fd[fd]->pipe_ptr;
if(running->fd[fd] ==0){
printf("Error: fd is not open\n");
return -1;
}
if(running->fd[fd]->mode != READ_PIPE){
printf("Error: fd mode is not read\n");
return -2;
}
printf("BEFORE READ:\n");
show_pipe(pipe);
while(rbytes < n){
if(pipe->nwriter == 0){
/* read as much as it can; either nbytes or until no more data.
return ACTUAL number of bytes read. */
// Put the byte into umode, then destroy it in the pipe
printf("NO WRITER\n");
if(pipe->data != 0){
byte = pipe->buf[pipe->tail];
printf("READ BYTE: %c[%d]\n", byte, pipe->tail);
put_byte(byte, running->uss, offset);
pipe->buf[pipe->tail] = 0;
pipe->room++;
pipe->data--;
rbytes++;
offset++;
pipe->tail++;
pipe->tail %= PIPE_SIZE;
}else{
printf("AFTER READ:\n");
show_pipe(pipe);
return rbytes;
}
// ksleep(&(pipe->data));
}else{
if(pipe->data != 0){
byte = pipe->buf[pipe->tail];
printf("READ BYTE: %c[%d]\n", byte, pipe->tail);
put_byte(byte, running->uss, offset);
pipe->buf[pipe->tail] = 0;
pipe->room++;
pipe->data--;
rbytes++;
offset++;
pipe->tail++;
pipe->tail %= PIPE_SIZE;
kwakeup(&(pipe->room));
}else{
kwakeup(&(pipe->room));
ksleep(&(pipe->data));
}
}
}
printf("AFTER READ:\n");
show_pipe(pipe);
return rbytes;
}
int kwrite_pipe(int fd, char *buf, int n){
char c; int r = 0;
PIPE *pp; OFT* op;
printf("Attempt pipe write of %d bytes to fd (%d)\n", n, fd);
// if(n <= 0){
// return 0;
// }
if(fd >= NFD || fd < 0){
printf("invalid file descriptor (out of bounds).\n");
return -1;
}
if(!running->fd[fd]){
printf("invalid file descriptor (not opened).\n");
return -1;
}
op = running->fd[fd];
pp = op->pipe_ptr;
if(op->mode != WRITE_PIPE){
printf("fd (%d) is not for pipe read\n", fd);
return -1;
}
printf("pipe before writing\n");
show_pipe(pp);
while(n){
if(!pp->nreader){
printf("proc %d : BROKEN_PIPE error\n", running->pid);
kexit(0x0D);
}
while(pp->room && n){
pp->buf[pp->head++] = get_byte(running->uss, buf);
pp->head = pp->head % PSIZE;
pp->data++; pp->room--;
n--; r++; buf++;
}
kwakeup(&(pp->data));
if(n==0){
printf("pipe after writing\n");
show_pipe(pp);
return r;
}
printf("pipe before writer goes to sleep\n");
show_pipe(pp);
ksleep(&(pp->room));
}
return r;
}
int kread_pipe(int fd, char *buf, int n){
int r = 0;
OFT *op;
PIPE *pp;
char c;
printf("Attempted to read %d bytes from fd (%d)\n", n, fd);
if(n <= 0){
return 0;
}
if(fd >= NFD || fd < 0){
printf("invalid file descriptor (out of bounds).\n");
return -1;
}
if(!running->fd[fd]){
printf("invalid file descriptor (not opened).\n");
return -1;
}
op = running->fd[fd];
pp = op->pipe_ptr;
if(op->mode != READ_PIPE){
printf("fd (%d) is not for pipe read\n", fd);
return -1;
}
printf("pipe before reading\n");
show_pipe(pp);
while(n){
while(pp->data){
c = pp->buf[(pp->tail)++];
put_byte(c, running->uss, buf);
pp->tail = pp->tail % PSIZE;
pp->data--; pp->room++;
n--; r++; buf++;
if(n == 0) break;
}
if(n == 0 || r){
kwakeup(&(pp->room));
printf("pipe after reading\n");
show_pipe(pp);
return r;
}
//need some but didn't get none
if(pp->nwriter){
printf("pipe before reader goes to sleep\n");
show_pipe(pp);
kwakeup(&(pp->room));
ksleep(&(pp->data));
continue;
}
//pipe has no writer and no data
printf("pipe had no writer and no data\n");
return 0;
}
printf("how tf do we get here?\n");
return 0;
}
