stos: ke: Add PBI image parser

Signed-off-by: Chloe M. <chloe@mensia.org>
2026-06-23 02:34:13 +00:00
parent 2c7d55e950
commit 1df447c91d
3 changed files with 130 additions and 0 deletions
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Pre-boot image manager
+ * Author:      Chloe M.
+ */
+
+#include <ex/pbi.h>
+#include <ke/bpal.h>
+#include <stdef.h>
+#include <string.h>
+
+#define REF_MAGIC "CUMHOLE"
+#define REF_MAGIC_LEN 8
+#define REF_PATH_LEN 256
+
+static BPAL_MODULE Pbi;
+
+/*
+ * A reference is an entry within the table that refers
+ * to a block of data after the reference table.
+ *
+ * @Magic:      Reference magic
+ * @Path:       File path
+ * @Size:       File size
+ * @DataOff:    Data offset
+ */
+typedef PACKED struct {
+    CHAR Magic[REF_MAGIC_LEN];
+    CHAR Path[REF_PATH_LEN];
+    USIZE Size;
+    USIZE DataOff;
+} HOLE_REF;
+
+ST_STATUS
+ExPbiLookup(CHAR *Path, EX_BPI_FILE *Result)
+{
+    HOLE_REF *Ref;
+    USIZE PathLen;
+
+    if (Path == NULL || Result == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    if (*Path != '/') {
+        return STATUS_NOT_FOUND;
+    }
+
+    ++Path;
+    Ref = Pbi.Data;
+    PathLen = RtlStrLen(Path);
+
+    for (;;) {
+        if (RtlMemCmp(Ref->Magic, REF_MAGIC, REF_MAGIC_LEN) != 0) {
+            break;
+        }
+
+        if (Ref->Path[0] != *Path) {
+            ++Ref;
+            continue;
+        }
+
+        if (RtlMemCmp(Ref->Path, Path, PathLen) == 0) {
+            Result->Data = PTR_OFFSET(Pbi.Data, Ref->DataOff);
+            Result->Size = Ref->Size;
+            return STATUS_SUCCESS;
+        }
+
+        ++Ref;
+    }
+
+    return STATUS_NOT_FOUND;
+}
+
+ST_STATUS
+ExPbiInit(VOID)
+{
+    BPAL_HANDLE Bpal;
+    ST_STATUS Status;
+
+    KeBpalGetHandle(&Bpal);
+
+    Status = Bpal.ModuleLookup("/boot/pbi.hole", &Pbi);
+    if (Status != STATUS_SUCCESS) {
+        return Status;
+    }
+
+    return STATUS_SUCCESS;
+}