1 files changed, 90 insertions, 0 deletions
diff --git a/src/initrd.c b/src/initrd.c
new file mode 100644
index 0000000..7b68c40
--- /dev/null
+++ b/src/initrd.c
@@ -0,0 +1,90 @@
+#include <initrd.h>
+
+extern uint8_t _binary_initrd_img_start[];
+extern uint8_t _binary_initrd_img_size[];
+
+static const void *initrd_start = (void *)_binary_initrd_img_start;
+static const uint32_t initrd_size = (uint32_t)_binary_initrd_img_size;
+
+static const char *initrd_sig = "!<arch>\n";
+
+uint8_t initrd_validate(void)
+{
+	initrd_header *header = (initrd_header *)initrd_start;
+	for (uint8_t i = 0; i < 8; i++) {
+		if (header->signature[i] != initrd_sig[i])
+			return 0;
+	}
+
+	return 1;
+}
+
+uint8_t initrd_nametest(char *file, const char *want)
+{
+	for (uint8_t i = 0; i < 16; i++) {
+		if (want[i] == '\0')
+			return (file[i] == '/');
+		else if (want[i] != file[i])
+			return 0;
+	}
+
+	return 0;
+}
+
+uint32_t pow10(uint8_t n)
+{
+	uint32_t i = 1;
+	while (n--)
+		i *= 10;
+	return i;
+}
+
+uint32_t initrd_getsize(initrd_file *file)
+{
+	uint32_t size = 0;
+	char *p = file->size + 10;
+	while (*--p == ' ');
+
+	for (int8_t i = p - file->size, j = 0; i >= 0; i--, j++)
+		size += (*p-- - '0') * pow10(j);
+
+	return size;
+}
+
+initrd_file *initrd_getfileptr(const char *name)
+{
+	initrd_file *file = (initrd_file *)(initrd_start + sizeof(initrd_header));
+	uint32_t offset = sizeof(initrd_header);
+
+	while (offset < initrd_size) {
+		if (initrd_nametest(file->name, name))
+			return file;
+		uint32_t size = initrd_getsize(file) + sizeof(initrd_file);
+		offset += size;
+		file += size;
+	}
+
+	return 0;
+}
+
+char *initrd_getfile(const char *name)
+{
+	initrd_file *file = initrd_getfileptr(name);
+	if (file == 0)
+		return 0;
+
+
+	char *ptr = (char *)((void *)file + sizeof(initrd_file));
+	ptr[initrd_getsize(file) - 1] = 0;
+	return ptr;
+}
+
+uint32_t initrd_getfilesize(const char *name)
+{
+	initrd_file *file = initrd_getfileptr(name);
+	if (file == 0)
+		return 0;
+
+	return initrd_getsize(file);
+}
+