create a simple CPIO parser for initrd's

2 files changed, 36 insertions, 0 deletions

diff --git a/include/common.h b/include/common.h
index 88ee8c4..d26b8ae 100644
--- a/include/common.h
+++ b/include/common.h
@@ -16,6 +16,19 @@ static inline int strcmp(const char *str1, const char* str2) {
     return *(const unsigned char *)str1 - *(const unsigned char *)str2;
 }
 
+static inline int memcmp(const void *s1, const void *s2, size_t n) {
+    const unsigned char *p1 = (const unsigned char *)s1;
+    const unsigned char *p2 = (const unsigned char *)s2;
+
+    for (size_t i = 0; i < n; i++) {
+        if (p1[i] != p2[i]) {
+            return p1[i] - p2[i];
+        }
+    }
+
+    return 0;
+}
+
 static inline void *memcpy(void *restrict dest, const void* restrict src, size_t size) {
     unsigned char *d = (unsigned char *)dest;
     unsigned char *s = (unsigned char *)src;
diff --git a/include/cpio.h b/include/cpio.h
new file mode 100644
index 0000000..3bb40c0
--- /dev/null
+++ b/include/cpio.h
@@ -0,0 +1,23 @@
+#pragma once
+#include <types.h>
+#define CPIO_HEADER_LEN 110
+
+struct cpio_newc_hdr {
+    char magic[6];
+    char ino[8];
+    char mode[8];
+    char uid[8];
+    char gid[8];
+    char nlink[8];
+    char mtime[8];
+    char filesize[8];
+    char devmajor[8];
+    char devminor[8];
+    char rdevmajor[8];
+    char rdevminor[8];
+    char namesize[8];
+    char check[8];
+};
+
+void *cpio_get_file(void *archive, size_t size, const char *filename);
+