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, 94 insertions, 0 deletions

diff --git a/kernel/fs/shm.c b/kernel/fs/shm.c
new file mode 100644
index 0000000..4d5f2ab
--- /dev/null
+++ b/kernel/fs/shm.c
@@ -0,0 +1,94 @@
+#include <assert.h>
+#include <errno.h>
+#include <fs/shm.h>
+#include <fs/vfs.h>
+#include <hashmap/hashmap.h>
+#include <mmu.h>
+#include <sched/scheduler.h>
+#include <stddef.h>
+
+HashMap *shared_memory_objects;
+
+void shm_init(void) { shared_memory_objects = hashmap_create(10); }
+
+int shm_write(uint8_t *buffer, uint64_t offset, uint64_t len, vfs_fd_t *fd) {
+  vfs_vm_object_t *p = fd->inode->internal_object;
+
+  if (offset > p->size)
+    return -EFBIG;
+
+  if (offset + len > p->size)
+    len = p->size - offset;
+
+  memcpy((void *)((uintptr_t)((uintptr_t)p->virtual_object + offset)), buffer,
+         len);
+  return len;
+}
+
+int shm_read(uint8_t *buffer, uint64_t offset, uint64_t len, vfs_fd_t *fd) {
+  vfs_vm_object_t *p = fd->inode->internal_object;
+
+  if (offset > p->size)
+    return -EFBIG;
+
+  if (offset + len > p->size)
+    len = p->size - offset;
+
+  memcpy((void *)buffer,
+         (void *)((uintptr_t)((uintptr_t)p->virtual_object + offset)), len);
+  return len;
+}
+
+vfs_vm_object_t *shm_get_vm_object(uint64_t length, uint64_t offset,
+                                   vfs_fd_t *fd) {
+  (void)length;
+  (void)offset;
+  vfs_vm_object_t *p = fd->inode->internal_object;
+  return p;
+}
+
+int shm_ftruncate(vfs_fd_t *fd, size_t length) {
+  vfs_vm_object_t *p = fd->inode->internal_object;
+  p->size = length;
+  p->virtual_object = ksbrk(length);
+  int n = (uintptr_t)align_page((void *)(uint32_t)length) / 0x1000;
+  p->object = kmalloc(sizeof(void *) * n);
+  for (int i = 0; i < n; i++)
+    p->object[i] =
+        (void *)(get_page(p->virtual_object + (i * 0x1000), NULL, 0, 0)->frame *
+                 0x1000);
+  return 0;
+}
+
+int shm_open(const char *name, int oflag, mode_t mode) {
+  // Try to find or create a new shared memory object.
+  vfs_vm_object_t *internal_object =
+      hashmap_get_entry(shared_memory_objects, name);
+  if (!internal_object) {
+    //    if (!(oflag & O_CREAT))
+    //      return -EMFILE;
+    internal_object = kmalloc(sizeof(vfs_vm_object_t));
+    internal_object->object = NULL;
+    internal_object->size = 0;
+    hashmap_add_entry(shared_memory_objects, name, internal_object, NULL, 0);
+  }
+
+  vfs_inode_t *inode = vfs_create_inode(
+      0 /*inode_num*/, 0 /*type*/, 1 /*has_data*/, 1 /*can_write*/,
+      1 /*is_open*/, internal_object, 0 /*file_size*/, NULL /*open*/,
+      NULL /*create_file*/, shm_read, shm_write, NULL /*close*/,
+      NULL /*create_directory*/, shm_get_vm_object, shm_ftruncate);
+
+  vfs_fd_t *fd_ptr;
+  int fd = vfs_create_fd(oflag, mode, inode, &fd_ptr);
+  if (-1 == fd) {
+    kfree(inode);
+    return -EMFILE;
+  }
+  return fd;
+}
+
+int shm_unlink(const char *name) {
+  (void)name;
+  return 0;
+}