stos: ke: Add PBI image parser

Signed-off-by: Chloe M. <chloe@mensia.org>

paw/stos/ex/pbi.c

@@ -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;
+}

paw/stos/head/ex/pbi.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Pre-boot image manager
+ * Author:      Chloe M.
+ */
+
+#ifndef _EX_PBI_H_
+#define _EX_PBI_H_ 1
+
+#include <stapi/status.h>
+#include <stdef.h>
+
+/*
+ * Represents an BPI file
+ *
+ * @Data: Actual raw data
+ * @Size:   Byte count
+ */
+typedef struct {
+    VOID *Data;
+    USIZE Size;
+} EX_BPI_FILE;
+
+/*
+ * Look up a file from the pre-boot image
+ *
+ * @Path: Path to file to lookup
+ * @Result: Result is written here
+ */
+ST_STATUS ExPbiLookup(CHAR *Path, EX_BPI_FILE *Result);
+
+/*
+ * Initialize the pre-boot image manaer
+ */
+ST_STATUS ExPbiInit(VOID);
+
+#endif  /* !_EX_PBI_H_ */

paw/stos/ke/Makefile

@@ -14,6 +14,7 @@ CFILES += $(shell find ../xt -name "*.c")
 CFILES += $(shell find ../lib -name "*.c")
 CFILES += $(shell find ../drivers -name "*.c")
 CFILES += $(shell find ../mm -name "*.c")
+CFILES += $(shell find ../ex -name "*.c")
 CFILES += $(shell find bpal -name "*.c")
 DFILES = $(CFILES:.c=.d)
 OFILES = $(CFILES:.c=.o)