fat_io_lib finally works, implement virtual partition devices, manage devices via string keys

kernel/device/partitions.c

@@ -0,0 +1,65 @@
+#include <device/device.h>
+#include <device/partdrv.h>
+#include <device/partitions.h>
+#include <devices.h>
+#include <libk/fieldsizeof.h>
+#include <libk/lengthof.h>
+#include <libk/printf.h>
+#include <libk/std.h>
+#include <libk/string.h>
+#include <status.h>
+#include <sys/debug.h>
+
+static int device_probe_partitions_dos (struct device* device) {
+  struct dos_mbr mbr;
+  memset (&mbr, 0, sizeof (mbr));
+  size_t sector = 0;
+  size_t sector_count = 1;
+  size_t sector_size;
+
+  device_op_func_t ops[] = {
+      [XDRV_GET_SIZE] = &partdrv_get_size,
+      [XDRV_GET_SECTOR_SIZE] = &partdrv_get_sector_size,
+      [XDRV_GET_DEVICE_TYPE] = &partdrv_get_device_type,
+      [XDRV_READ] = &partdrv_read,
+      [XDRV_WRITE] = &partdrv_write,
+  };
+
+  spin_lock (&device->lock);
+
+  device_op (device, XDRV_GET_SECTOR_SIZE, NULL, NULL, &sector_size);
+
+  int ret = device_op (device, XDRV_READ, NULL, NULL, &sector, &sector_count, &mbr);
+
+  if (ret < 0) {
+    spin_unlock (&device->lock);
+    return ret;
+  }
+
+  if (!(mbr.valid_sign[0] == 0x55 && mbr.valid_sign[1] == 0xAA)) {
+    spin_unlock (&device->lock);
+    return -ST_PARTITION_ERROR;
+  }
+
+  for (size_t i = 0; i < lengthof (mbr.ptes); i++) {
+    struct dos_pte* pte = &mbr.ptes[i];
+
+    struct partdrv_init init = {
+        .start_sector = pte->start_lba,
+        .total_size = pte->sector_count * sector_size,
+        .super = device,
+    };
+
+    char key[fieldsizeof (struct device, key)];
+    memset (key, 0, sizeof (key));
+    snprintf (key, sizeof (key), "%sp%zu", device->key, i);
+
+    device_create (key, ops, lengthof (ops), &partdrv_init, &partdrv_fini, &init);
+  }
+
+  spin_unlock (&device->lock);
+
+  return ST_OK;
+}
+
+int device_probe_partitions (struct device* device) { return device_probe_partitions_dos (device); }