+
+struct exclusion_tag
+{
+ const char *name;
+ size_t length;
+ enum exclusion_tag_type type;
+ bool (*predicate) (const char *name);
+ struct exclusion_tag *next;
+};
+
+static struct exclusion_tag *exclusion_tags;
+
+void
+add_exclusion_tag (const char *name, enum exclusion_tag_type type,
+ bool (*predicate) (const char *name))
+{
+ struct exclusion_tag *tag = xmalloc (sizeof tag[0]);
+ tag->next = exclusion_tags;
+ tag->name = name;
+ tag->type = type;
+ tag->predicate = predicate;
+ tag->length = strlen (name);
+ exclusion_tags = tag;
+}
+
+void
+exclusion_tag_warning (const char *dirname, const char *tagname,
+ const char *message)
+{
+ if (verbose_option)
+ WARNOPT (WARN_CACHEDIR,
+ (0, 0,
+ _("%s: contains a cache directory tag %s; %s"),
+ quotearg_colon (dirname),
+ quotearg_n (1, tagname),
+ message));
+}
+
+enum exclusion_tag_type
+check_exclusion_tags (const char *dirname, const char **tag_file_name)
+{
+ static char *tagname;
+ static size_t tagsize;
+ struct exclusion_tag *tag;
+ size_t dlen = strlen (dirname);
+ int addslash = !ISSLASH (dirname[dlen-1]);
+ char *nptr = NULL;
+
+ for (tag = exclusion_tags; tag; tag = tag->next)
+ {
+ size_t size = dlen + addslash + tag->length + 1;
+ if (size > tagsize)
+ {
+ tagsize = size;
+ tagname = xrealloc (tagname, tagsize);
+ }
+
+ if (!nptr)
+ {
+ strcpy (tagname, dirname);
+ nptr = tagname + dlen;
+ if (addslash)
+ *nptr++ = '/';
+ }
+ strcpy (nptr, tag->name);
+ if (access (tagname, F_OK) == 0
+ && (!tag->predicate || tag->predicate (tagname)))
+ {
+ if (tag_file_name)
+ *tag_file_name = tag->name;
+ return tag->type;
+ }
+ }
+
+ return exclusion_tag_none;
+}
+
+/* Exclusion predicate to test if the named file (usually "CACHEDIR.TAG")
+ contains a valid header, as described at:
+ http://www.brynosaurus.com/cachedir
+ Applications can write this file into directories they create
+ for use as caches containing purely regenerable, non-precious data,
+ allowing us to avoid archiving them if --exclude-caches is specified. */
+
+#define CACHEDIR_SIGNATURE "Signature: 8a477f597d28d172789f06886806bc55"
+#define CACHEDIR_SIGNATURE_SIZE (sizeof CACHEDIR_SIGNATURE - 1)
+
+bool
+cachedir_file_p (const char *name)
+{
+ bool tag_present = false;
+ int fd = open (name, O_RDONLY);
+ if (fd >= 0)
+ {
+ static char tagbuf[CACHEDIR_SIGNATURE_SIZE];
+
+ if (read (fd, tagbuf, CACHEDIR_SIGNATURE_SIZE)
+ == CACHEDIR_SIGNATURE_SIZE
+ && memcmp (tagbuf, CACHEDIR_SIGNATURE, CACHEDIR_SIGNATURE_SIZE) == 0)
+ tag_present = true;
+
+ close (fd);
+ }
+ return tag_present;
+}
+
projects / chaz / tar / blobdiff