Write xattr as LIBARCHIVE.xattr and/or SCHILY.xattr

Introduce flags to write extended attributes either with the prefix
LIBARCHIVE.xattr or SCHIL.xattr. For the existing bsdtar formats
'pax' and 'posix' we now choose to write both. This enables backwards
compatibility and allow us to exchange tar files carrying extended
attributes with GNU tar.

diff --git a/libarchive/archive_write_set_format_pax.c b/libarchive/archive_write_set_format_pax.c
index 0c5322d485d92a3718c8065a47d209ffe3bb7f55..cb0e5c31598c5e122b261ee727cb83d247d7ebab 100644 (file)
--- a/libarchive/archive_write_set_format_pax.c
+++ b/libarchive/archive_write_set_format_pax.c
@@ -62,6 +62,10 @@ struct pax {
        struct sparse_block     *sparse_tail;
        struct archive_string_conv *sconv_utf8;
        int                      opt_binary;
+
+       unsigned flags;
+#define WRITE_SCHILY_XATTR       (1 << 0)
+#define WRITE_LIBARCHIVE_XATTR   (1 << 1)
 };
 
 static void             add_pax_attr(struct archive_string *, const char *key,
@@ -139,6 +143,8 @@ archive_write_set_format_pax(struct archive *_a)
                    "Can't allocate pax data");
                return (ARCHIVE_FATAL);
        }
+       pax->flags = WRITE_LIBARCHIVE_XATTR | WRITE_SCHILY_XATTR;
+
        a->format_data = pax;
        a->format_name = "pax";
        a->format_options = archive_write_pax_options;
@@ -331,17 +337,43 @@ add_pax_attr_binary(struct archive_string *as, const char *key,
        archive_strappend_char(as, '\n');
 }
 
+static void
+archive_write_pax_header_xattr(struct pax *pax, const char *encoded_name,
+    const void *value, size_t value_len)
+{
+       struct archive_string s;
+       char *encoded_value;
+
+       if (pax->flags & WRITE_LIBARCHIVE_XATTR) {
+               encoded_value = base64_encode((const char *)value, value_len);
+
+               if (encoded_name != NULL && encoded_value != NULL) {
+                       archive_string_init(&s);
+                       archive_strcpy(&s, "LIBARCHIVE.xattr.");
+                       archive_strcat(&s, encoded_name);
+                       add_pax_attr(&(pax->pax_header), s.s, encoded_value);
+                       archive_string_free(&s);
+               }
+               free(encoded_value);
+       }
+       if (pax->flags & WRITE_SCHILY_XATTR) {
+               archive_string_init(&s);
+               archive_strcpy(&s, "SCHILY.xattr.");
+               archive_strcat(&s, encoded_name);
+               add_pax_attr_binary(&(pax->pax_header), s.s, value, value_len);
+               archive_string_free(&s);
+       }
+}
+
 static int
 archive_write_pax_header_xattrs(struct archive_write *a,
     struct pax *pax, struct archive_entry *entry)
 {
-       struct archive_string s;
        int i = archive_entry_xattr_reset(entry);
 
        while (i--) {
                const char *name;
                const void *value;
-               char *encoded_value;
                char *url_encoded_name = NULL, *encoded_name = NULL;
                size_t size;
                int r;
@@ -362,16 +394,9 @@ archive_write_pax_header_xattrs(struct archive_write *a,
                        }
                }
 
-               encoded_value = base64_encode((const char *)value, size);
+               archive_write_pax_header_xattr(pax, encoded_name,
+                   value, size);
 
-               if (encoded_name != NULL && encoded_value != NULL) {
-                       archive_string_init(&s);
-                       archive_strcpy(&s, "LIBARCHIVE.xattr.");
-                       archive_strcat(&s, encoded_name);
-                       add_pax_attr(&(pax->pax_header), s.s, encoded_value);
-                       archive_string_free(&s);
-               }
-               free(encoded_value);
        }
        return (ARCHIVE_OK);
 }