toaruos/kernel/fs/pipe.c
2013-03-22 11:58:22 -07:00

228 lines
6.0 KiB
C

/* vim: tabstop=4 shiftwidth=4 noexpandtab
* Buffered Pipe
*/
#include <system.h>
#include <fs.h>
#include <pipe.h>
#include <logging.h>
#define DEBUG_PIPES 0
uint32_t read_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
uint32_t write_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
void open_pipe(fs_node_t *node, uint8_t read, uint8_t write);
void close_pipe(fs_node_t *node);
static inline size_t pipe_unread(pipe_device_t * pipe) {
if (pipe->read_ptr == pipe->write_ptr) {
return 0;
}
if (pipe->read_ptr > pipe->write_ptr) {
return (pipe->size - pipe->read_ptr) + pipe->write_ptr;
} else {
return (pipe->write_ptr - pipe->read_ptr);
}
}
size_t pipe_size(fs_node_t * node) {
pipe_device_t * pipe = (pipe_device_t *)node->inode;
return pipe_unread(pipe);
}
static inline size_t pipe_available(pipe_device_t * pipe) {
if (pipe->read_ptr == pipe->write_ptr) {
return pipe->size - 1;
}
if (pipe->read_ptr > pipe->write_ptr) {
return pipe->read_ptr - pipe->write_ptr - 1;
} else {
return (pipe->size - pipe->write_ptr) + pipe->read_ptr - 1;
}
}
static inline void pipe_increment_read(pipe_device_t * pipe) {
pipe->read_ptr++;
if (pipe->read_ptr == pipe->size) {
pipe->read_ptr = 0;
}
}
static inline void pipe_increment_write(pipe_device_t * pipe) {
pipe->write_ptr++;
if (pipe->write_ptr == pipe->size) {
pipe->write_ptr = 0;
}
}
static inline void pipe_increment_write_by(pipe_device_t * pipe, size_t amount) {
pipe->write_ptr = (pipe->write_ptr + amount) % pipe->size;
}
uint32_t read_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
assert(node->inode != 0 && "Attempted to read from a fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
#if DEBUG_PIPES
if (pipe->size > 300) { /* Ignore small pipes (ie, keyboard) */
kprintf("[debug] Call to read from pipe 0x%x\n", node->inode);
kprintf(" Unread bytes: %d\n", pipe_unread(pipe));
kprintf(" Total size: %d\n", pipe->size);
kprintf(" Request size: %d\n", size);
kprintf(" Write pointer: %d\n", pipe->write_ptr);
kprintf(" Read pointer: %d\n", pipe->read_ptr);
kprintf(" Buffer address: 0x%x\n", pipe->buffer);
}
#endif
size_t collected = 0;
while (collected == 0) {
spin_lock(&pipe->lock);
while (pipe_unread(pipe) > 0 && collected < size) {
buffer[collected] = pipe->buffer[pipe->read_ptr];
pipe_increment_read(pipe);
collected++;
}
spin_unlock(&pipe->lock);
wakeup_queue(pipe->wait_queue);
//switch_from_cross_thread_lock();
/* Deschedule and switch */
if (collected == 0) {
sleep_on(pipe->wait_queue);
}
}
return collected;
}
uint32_t write_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
assert(node->inode != 0 && "Attempted to write to a fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
#if DEBUG_PIPES
if (pipe->size > 300) { /* Ignore small pipes (ie, keyboard) */
kprintf("[debug] Call to write to pipe 0x%x\n", node->inode);
kprintf(" Available space: %d\n", pipe_available(pipe));
kprintf(" Total size: %d\n", pipe->size);
kprintf(" Request size: %d\n", size);
kprintf(" Write pointer: %d\n", pipe->write_ptr);
kprintf(" Read pointer: %d\n", pipe->read_ptr);
kprintf(" Buffer address: 0x%x\n", pipe->buffer);
kprintf(" Write: %s\n", buffer);
}
#endif
size_t written = 0;
while (written < size) {
spin_lock(&pipe->lock);
#if 0
size_t available = 0;
if (pipe->read_ptr <= pipe->write_ptr) {
available = pipe->size - pipe->write_ptr;
} else {
available = pipe->read_ptr - pipe->write_ptr - 1;
}
if (available) {
available = min(available, size - written);
memcpy(&pipe->buffer[pipe->write_ptr], buffer, available);
pipe_increment_write_by(pipe, available);
written += available;
}
#else
while (pipe_available(pipe) > 0 && written < size) {
pipe->buffer[pipe->write_ptr] = buffer[written];
pipe_increment_write(pipe);
written++;
}
#endif
spin_unlock(&pipe->lock);
wakeup_queue(pipe->wait_queue);
if (written < size) {
sleep_on(pipe->wait_queue);
}
}
return written;
}
void open_pipe(fs_node_t * node, uint8_t read, uint8_t write) {
assert(node->inode != 0 && "Attempted to open a fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
/* Add a reference */
pipe->refcount++;
return;
}
void close_pipe(fs_node_t * node) {
assert(node->inode != 0 && "Attempted to close an already fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
/* Drop one reference */
pipe->refcount--;
/* Check the reference count number */
if (pipe->refcount == 0) {
#if 0
/* No other references exist, free the pipe (but not its buffer) */
free(pipe->buffer);
list_free(pipe->wait_queue);
free(pipe->wait_queue);
free(pipe);
/* And let the creator know there are no more references */
node->inode = 0;
#endif
}
return;
}
fs_node_t * make_pipe(size_t size) {
fs_node_t * fnode = malloc(sizeof(fs_node_t));
pipe_device_t * pipe = malloc(sizeof(pipe_device_t));
fnode->inode = 0;
fnode->name[0] = '\0';
sprintf(fnode->name, "[pipe]");
fnode->uid = 0;
fnode->gid = 0;
fnode->flags = FS_PIPE;
fnode->read = read_pipe;
fnode->write = write_pipe;
fnode->open = open_pipe;
fnode->close = close_pipe;
fnode->readdir = NULL;
fnode->finddir = NULL;
fnode->ioctl = NULL; /* TODO ioctls for pipes? maybe */
fnode->get_size = pipe_size;
fnode->atime = now();
fnode->mtime = fnode->atime;
fnode->ctime = fnode->atime;
fnode->inode = (uintptr_t)pipe;
pipe->buffer = malloc(size);
pipe->write_ptr = 0;
pipe->read_ptr = 0;
pipe->size = size;
pipe->refcount = 0;
pipe->lock = 0;
pipe->wait_queue = list_create();
return fnode;
}