Cleanup: split libtar header, move to sub directory

Some of the on-disk format internals are moved to a separate header
and some of the stuff from internal.h is moved to that format header.
C++ guards are added in addtion.

Everything PAX related is moved to pax_header.c, some internal
functions are marked as static.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 116 insertions, 73 deletions

diff --git a/include/common.h b/include/common.h
index ab07461..91dccaa 100644
--- a/include/common.h
+++ b/include/common.h
@@ -25,7 +25,6 @@
 #include "io/std.h"
 #include "compat.h"
 #include "fstree.h"
-#include "tar.h"
 
 #include <stddef.h>
 
diff --git a/include/tar/format.h b/include/tar/format.h
new file mode 100644
index 0000000..53a4665
--- /dev/null
+++ b/include/tar/format.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * format.h
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#ifndef TAR_FORMAT_H
+#define TAR_FORMAT_H
+
+#include "sqfs/predef.h"
+
+typedef struct {
+	char name[100];
+	char mode[8];
+	char uid[8];
+	char gid[8];
+	char size[12];
+	char mtime[12];
+	char chksum[8];
+	char typeflag;
+	char linkname[100];
+	char magic[6];
+	char version[2];
+	char uname[32];
+	char gname[32];
+	char devmajor[8];
+	char devminor[8];
+	union {
+		struct {
+			char prefix[155];
+			char padding[12];
+		} posix;
+
+		struct {
+			char atime[12];
+			char ctime[12];
+			char offset[12];
+			char deprecated[4];
+			char unused;
+			struct {
+				char offset[12];
+				char numbytes[12];
+			} sparse[4];
+			char isextended;
+			char realsize[12];
+			char padding[17];
+		} gnu;
+	} tail;
+} tar_header_t;
+
+typedef struct {
+	struct {
+		char offset[12];
+		char numbytes[12];
+	} sparse[21];
+	char isextended;
+	char padding[7];
+} gnu_sparse_t;
+
+#define TAR_TYPE_FILE '0'
+#define TAR_TYPE_LINK '1'
+#define TAR_TYPE_SLINK '2'
+#define TAR_TYPE_CHARDEV '3'
+#define TAR_TYPE_BLOCKDEV '4'
+#define TAR_TYPE_DIR '5'
+#define TAR_TYPE_FIFO '6'
+
+#define TAR_TYPE_GNU_SLINK 'K'
+#define TAR_TYPE_GNU_PATH 'L'
+#define TAR_TYPE_GNU_SPARSE 'S'
+
+#define TAR_TYPE_PAX 'x'
+#define TAR_TYPE_PAX_GLOBAL 'g'
+
+#define TAR_MAGIC "ustar"
+#define TAR_VERSION "00"
+
+#define TAR_MAGIC_OLD "ustar "
+#define TAR_VERSION_OLD " "
+
+#define TAR_RECORD_SIZE (512)
+
+/* artificially imposed implementation limits */
+#define TAR_MAX_SYMLINK_LEN (65536)
+#define TAR_MAX_PATH_LEN (65536)
+#define TAR_MAX_PAX_LEN (65536)
+#define TAR_MAX_SPARSE_ENT (65536)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int read_octal(const char *str, int digits, sqfs_u64 *out);
+
+int read_number(const char *str, int digits, sqfs_u64 *out);
+
+void update_checksum(tar_header_t *hdr);
+
+bool is_checksum_valid(const tar_header_t *hdr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* TAR_FORMAT_H */
diff --git a/include/tar.h b/include/tar/tar.h
index dadc16e..128464e 100644
--- a/include/tar.h
+++ b/include/tar/tar.h
@@ -22,54 +22,6 @@ typedef struct sparse_map_t {
 	sqfs_u64 count;
 } sparse_map_t;
 
-typedef struct {
-	char name[100];
-	char mode[8];
-	char uid[8];
-	char gid[8];
-	char size[12];
-	char mtime[12];
-	char chksum[8];
-	char typeflag;
-	char linkname[100];
-	char magic[6];
-	char version[2];
-	char uname[32];
-	char gname[32];
-	char devmajor[8];
-	char devminor[8];
-	union {
-		struct {
-			char prefix[155];
-			char padding[12];
-		} posix;
-
-		struct {
-			char atime[12];
-			char ctime[12];
-			char offset[12];
-			char deprecated[4];
-			char unused;
-			struct {
-				char offset[12];
-				char numbytes[12];
-			} sparse[4];
-			char isextended;
-			char realsize[12];
-			char padding[17];
-		} gnu;
-	} tail;
-} tar_header_t;
-
-typedef struct {
-	struct {
-		char offset[12];
-		char numbytes[12];
-	} sparse[21];
-	char isextended;
-	char padding[7];
-} gnu_sparse_t;
-
 typedef struct tar_xattr_t {
 	struct tar_xattr_t *next;
 	char *key;
@@ -95,28 +47,9 @@ typedef struct {
 	sqfs_s64 mtime;
 } tar_header_decoded_t;
 
-#define TAR_TYPE_FILE '0'
-#define TAR_TYPE_LINK '1'
-#define TAR_TYPE_SLINK '2'
-#define TAR_TYPE_CHARDEV '3'
-#define TAR_TYPE_BLOCKDEV '4'
-#define TAR_TYPE_DIR '5'
-#define TAR_TYPE_FIFO '6'
-
-#define TAR_TYPE_GNU_SLINK 'K'
-#define TAR_TYPE_GNU_PATH 'L'
-#define TAR_TYPE_GNU_SPARSE 'S'
-
-#define TAR_TYPE_PAX 'x'
-#define TAR_TYPE_PAX_GLOBAL 'g'
-
-#define TAR_MAGIC "ustar"
-#define TAR_VERSION "00"
-
-#define TAR_MAGIC_OLD "ustar "
-#define TAR_VERSION_OLD " "
-
-#define TAR_RECORD_SIZE (512)
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /*
   Returns < 0 on failure, > 0 if cannot encode, 0 on success.
@@ -140,8 +73,6 @@ int skip_entry(istream_t *fp, sqfs_u64 size);
 
 int read_header(istream_t *fp, tar_header_decoded_t *out);
 
-void free_xattr_list(tar_xattr_t *list);
-
 void clear_header(tar_header_decoded_t *hdr);
 
 /*
@@ -150,4 +81,12 @@ void clear_header(tar_header_decoded_t *hdr);
 */
 int padd_file(ostream_t *fp, sqfs_u64 size);
 
+void free_sparse_list(sparse_map_t *sparse);
+
+void free_xattr_list(tar_xattr_t *list);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* TAR_H */