134 lines
3.2 KiB
C
134 lines
3.2 KiB
C
/**
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* @file kernel/vfs/unixpipe.c
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* @brief Implementation of Unix pipes.
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*
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* Provides for unidirectional communication between processes.
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*
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* @copyright
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* This file is part of ToaruOS and is released under the terms
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* of the NCSA / University of Illinois License - see LICENSE.md
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* Copyright (C) 2014-2021 K. Lange
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*/
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#include <errno.h>
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#include <kernel/types.h>
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#include <kernel/printf.h>
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#include <kernel/pipe.h>
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#include <kernel/string.h>
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#include <kernel/ringbuffer.h>
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#include <kernel/process.h>
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#include <kernel/signal.h>
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#include <sys/signal_defs.h>
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#include <sys/ioctl.h>
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#define UNIX_PIPE_BUFFER 4096
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struct unix_pipe {
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fs_node_t * read_end;
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fs_node_t * write_end;
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volatile int read_closed;
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volatile int write_closed;
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ring_buffer_t * buffer;
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};
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static void close_complete(struct unix_pipe * self) {
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ring_buffer_destroy(self->buffer);
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}
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static ssize_t read_unixpipe(fs_node_t * node, off_t offset, size_t size, uint8_t *buffer) {
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struct unix_pipe * self = node->device;
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if (self->write_closed && !ring_buffer_unread(self->buffer)) {
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return 0;
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}
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return ring_buffer_read(self->buffer, size, buffer);
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}
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static ssize_t write_unixpipe(fs_node_t * node, off_t offset, size_t size, uint8_t *buffer) {
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struct unix_pipe * self = node->device;
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if (self->read_closed) {
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send_signal(this_core->current_process->id, SIGPIPE, 1);
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return -EPIPE;
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}
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return ring_buffer_write(self->buffer, size, buffer);
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}
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static void close_read_pipe(fs_node_t * node) {
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struct unix_pipe * self = node->device;
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self->read_closed = 1;
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if (!self->write_closed) {
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ring_buffer_interrupt(self->buffer);
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}
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}
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static void close_write_pipe(fs_node_t * node) {
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struct unix_pipe * self = node->device;
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self->write_closed = 1;
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if (!self->read_closed) {
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ring_buffer_interrupt(self->buffer);
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if (!ring_buffer_unread(self->buffer)) {
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ring_buffer_alert_waiters(self->buffer);
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}
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}
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}
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static int check_pipe(fs_node_t * node) {
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struct unix_pipe * self = node->device;
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if (ring_buffer_unread(self->buffer) > 0) {
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return 0;
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}
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if (self->write_closed) return 0;
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return 1;
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}
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static int wait_pipe(fs_node_t * node, void * process) {
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struct unix_pipe * self = node->device;
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ring_buffer_select_wait(self->buffer, process);
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return 0;
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}
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int make_unix_pipe(fs_node_t ** pipes) {
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size_t size = UNIX_PIPE_BUFFER;
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pipes[0] = malloc(sizeof(fs_node_t));
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pipes[1] = malloc(sizeof(fs_node_t));
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memset(pipes[0], 0, sizeof(fs_node_t));
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memset(pipes[1], 0, sizeof(fs_node_t));
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snprintf(pipes[0]->name, 100, "[pipe:read]");
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snprintf(pipes[1]->name, 100, "[pipe:write]");
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pipes[0]->mask = 0666;
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pipes[1]->mask = 0666;
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pipes[0]->flags = FS_PIPE;
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pipes[1]->flags = FS_PIPE;
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pipes[0]->read = read_unixpipe;
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pipes[1]->write = write_unixpipe;
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pipes[0]->close = close_read_pipe;
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pipes[1]->close = close_write_pipe;
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/* Read end can wait */
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pipes[0]->selectcheck = check_pipe;
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pipes[0]->selectwait = wait_pipe;
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struct unix_pipe * internals = malloc(sizeof(struct unix_pipe));
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internals->read_end = pipes[0];
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internals->write_end = pipes[1];
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internals->read_closed = 0;
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internals->write_closed = 0;
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internals->buffer = ring_buffer_create(size);
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pipes[0]->device = internals;
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pipes[1]->device = internals;
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return 0;
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}
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