1 files changed, 42 insertions, 0 deletions
diff --git a/initrd.c b/initrd.c
new file mode 100644
index 0000000..3f36cd9
--- /dev/null
+++ b/initrd.c
@@ -0,0 +1,42 @@
+#include <stdint.h>
+#include <string.h>
+
+extern uint8_t *initrd_start;
+extern uint32_t initrd_size;
+
+char *getfile(uint32_t offset)
+{
+	char *ptr = initrd_start;
+	for (uint32_t i = 0; i < offset; i++) {
+		uint32_t len = *((uint32_t *)ptr);
+		uint32_t datalen = *((uint32_t *)(ptr + 4 + len));
+		ptr += len + datalen + 8;
+		if (ptr >= (char *)(initrd_start + initrd_size))
+			return 0;
+	}
+
+	return ptr;
+}
+
+char *readfile(const char *name)
+{
+	char *ptr;
+	for (uint32_t i = 0; ptr = getfile(i), ptr != 0; i++) {
+		uint32_t len = *((uint32_t *)ptr);
+		if (!strncmp(name, ptr + 4, len))
+			return ptr + len + 8;
+	}
+	return 0;
+}
+
+uint32_t filesize(const char *name)
+{
+	char *ptr;
+	for (uint32_t i = 0; ptr = getfile(i), ptr != 0; i++) {
+		uint32_t len = *((uint32_t *)ptr);
+		if (!strncmp(name, ptr + 4, len))
+			return *((uint32_t *)ptr + len + 4);
+	}
+	return 0;
+}
+