s3: libsmb: Add clistr_is_previous_version_path()

Looks for @GMT- token in pathname.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12165

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>

source3/libsmb/clistr.c

@@ -37,3 +37,31 @@ size_t clistr_pull_talloc(TALLOC_CTX *ctx,
 				  src_len,
 				  flags);
 }
+
+bool clistr_is_previous_version_path(const char *path)
+{
+	char *q;
+	time_t timestamp;
+	struct tm tm;
+	const char *p = strstr_m(path, "@GMT-");
+
+	if (p == NULL) {
+		return false;
+	}
+	if (p > path && (p[-1] != '\\')) {
+		return false;
+	}
+	q = strptime(p, GMT_FORMAT, &tm);
+	if (q == NULL) {
+		return false;
+	}
+	tm.tm_isdst = -1;
+	timestamp = timegm(&tm);
+	if (timestamp == (time_t)-1) {
+		return false;
+	}
+	if (q[0] != '\0' && q[0] != '\\') {
+		return false;
+	}
+	return true;
+}

source3/libsmb/proto.h

@@ -868,6 +868,7 @@ size_t clistr_pull_talloc(TALLOC_CTX *ctx,
 			  const void *src,
 			  int src_len,
 			  int flags);
+bool clistr_is_previous_version_path(const char *path);
 
 /* The following definitions come from libsmb/clitrans.c  */