starting to work on pty drivers, fork(), and scheduler redesign

kernel/drivers/pty/pty.c

@@ -0,0 +1,62 @@
+#include "lib/ringbuf.h"
+#include <drivers/pty/pty.h>
+
+uint32_t pty_master_read(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer) {
+    pty_t* pty = (pty_t*)node->data;
+    uint32_t bytes_read = 0;
+    while (bytes_read < size) {
+        char c;
+        if (ring_buf_read(&pty->slave_rb, &c) == 0) {
+            buffer[bytes_read++] = c;
+        } else {
+            break;
+        }
+    }
+    return bytes_read;
+}
+
+uint32_t pty_master_write(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer) {
+    pty_t* pty = (pty_t*)node->data;
+    uint32_t bytes_written = 0;
+
+    while (bytes_written < size) {
+        if (ring_buf_write(&pty->master_rb, buffer[bytes_written]) == 0) {
+            bytes_written++;
+            ring_buf_write(&pty->slave_rb, buffer[bytes_written-1]);
+        } else {
+            break;
+        }
+    }
+    return bytes_written;
+}
+
+uint32_t pty_slave_read(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer) {
+    pty_t* pty = (pty_t*)node->data;
+    uint32_t bytes_read = 0;
+
+    while (bytes_read < size) {
+        char c;
+        if (ring_buf_read(&pty->master_rb, &c) == 0) {
+            buffer[bytes_read++] = c;
+        } else {
+            break;
+        }
+    }
+
+    return bytes_read;
+}
+
+uint32_t pty_slave_write(struct vfs_node* node, uint32_t offset, uint32_t size, uint8_t* buffer) {
+    pty_t* pty = (pty_t*)node->data;
+    uint32_t bytes_written = 0;
+
+    while (bytes_written < size) {
+        if (ring_buf_write(&pty->slave_rb, buffer[bytes_written]) == 0) {
+            bytes_written++;
+        } else {
+            break;
+        }
+    }
+
+    return bytes_written;
+}