Meta: Move kernel and userland to their own folders.

This is to allow both the kernel and the userland to share certain
header files and to make the folder structure a bit more clear.

1 files changed, 97 insertions, 0 deletions

diff --git a/kernel/fs/fifo.c b/kernel/fs/fifo.c
new file mode 100644
index 0000000..d515ed7
--- /dev/null
+++ b/kernel/fs/fifo.c
@@ -0,0 +1,97 @@
+#include "fifo.h"
+#include <errno.h>
+
+#define STARTING_SIZE 4096
+
+void fifo_close(vfs_fd_t *fd) {
+  // TODO: Implement
+  (void)fd;
+  return;
+}
+
+int fifo_object_write(uint8_t *buffer, uint64_t offset, uint64_t len,
+                      FIFO_FILE *file) {
+  (void)offset;
+  file->has_data = 1;
+  if (file->write_len + len >= file->buffer_len) {
+    file->can_write = 0;
+    return -EAGAIN;
+  }
+  memcpy(file->buffer + file->write_len, buffer, len);
+  file->write_len += len;
+  return len;
+}
+
+int fifo_object_read(uint8_t *buffer, uint64_t offset, uint64_t len,
+                     FIFO_FILE *file) {
+  (void)offset;
+  if (file->write_len == 0) {
+    file->has_data = 0;
+    return -EAGAIN;
+  }
+
+  if (len == 0)
+    return 0;
+
+  file->can_write = 1;
+  if (len > file->write_len)
+    len = file->write_len;
+
+  memcpy(buffer, file->buffer, len);
+  // Shift bufffer to the left
+  memcpy(file->buffer, file->buffer + len, file->buffer_len - len);
+
+  file->write_len -= len;
+  if (file->write_len == 0) {
+    file->has_data = 0;
+  }
+  return len;
+}
+
+FIFO_FILE *create_fifo_object(void) {
+  FIFO_FILE *n = kmalloc(sizeof(FIFO_FILE));
+  n->buffer = kmalloc(STARTING_SIZE);
+  n->buffer_len = STARTING_SIZE;
+  n->write_len = 0;
+  return n;
+}
+
+int create_fifo(void) {
+
+  int fd_n = 0;
+  for (; get_current_task()->file_descriptors[fd_n]; fd_n++)
+    ;
+
+  vfs_fd_t *fd = kmalloc(sizeof(vfs_fd_t));
+  fd->flags = O_RDWR | O_NONBLOCK;
+  get_current_task()->file_descriptors[fd_n] = fd;
+  fd->inode = kmalloc(sizeof(vfs_inode_t));
+
+  fd->inode->internal_object = (void *)create_fifo_object();
+  fd->inode->open = NULL;
+  fd->inode->read = fifo_read;
+  fd->inode->write = fifo_write;
+  fd->inode->close = fifo_close;
+  fd->inode->get_vm_object = NULL;
+  fd->inode->is_open = 1;
+
+  return fd_n;
+}
+
+int fifo_write(uint8_t *buffer, uint64_t offset, uint64_t len, vfs_fd_t *fd) {
+  (void)offset;
+  FIFO_FILE *file = (FIFO_FILE *)fd->inode->internal_object;
+  int rc = fifo_object_write(buffer, offset, len, file);
+  fd->inode->has_data = file->has_data;
+  fd->inode->can_write = file->can_write;
+  return rc;
+}
+
+int fifo_read(uint8_t *buffer, uint64_t offset, uint64_t len, vfs_fd_t *fd) {
+  FIFO_FILE *file = (FIFO_FILE *)fd->inode->internal_object;
+  file->is_blocking = !(fd->flags & O_NONBLOCK);
+  int rc = fifo_object_read(buffer, offset, len, file);
+  fd->inode->has_data = file->has_data;
+  fd->inode->can_write = file->can_write;
+  return rc;
+}