Improve readdir extension.

4 files changed, 42 insertions, 10 deletions

diff --git a/extension/ChangeLog b/extension/ChangeLog
index 899f72d1..9b5affc3 100644
--- a/extension/ChangeLog
+++ b/extension/ChangeLog
@@ -1,3 +1,9 @@
+2012-08-28         Andrew J. Schorr     <aschorr@telemetry-investments.com>
+
+	* readdir.c: Have three states, 0, 1, 2 for never, fallback, and
+	always.
+	* readdir.3am: Adjust appropriately.
+
 2012-08-29         Arnold D. Robbins     <arnold@skeeve.com>
 
 	Make fts work everywhere by using our own source.
diff --git a/extension/readdir.3am b/extension/readdir.3am
index 9cb4862e..e7c6ee4f 100644
--- a/extension/readdir.3am
+++ b/extension/readdir.3am
@@ -5,7 +5,7 @@ readdir \- directory input parser for gawk
 .ft CW
 @load "readdir"
 .sp
-readdir_do_ftype(1)	# or 0
+readdir_do_ftype(2)	# or 0 or 1
 .ft R
 .SH DESCRIPTION
 The
@@ -43,12 +43,16 @@ for a socket, and
 (unknown) for anything else.
 .PP
 On systems without the file type information, calling
-.B readdir_do_ftype(1)
+.B readdir_do_ftype(2)
 causes the extension to use
 .IR stat (2)
 to retrieve the appropriate information. This is not the default, since
 .IR stat (2)
-is a potentially expensive operation.
+is a potentially expensive operation.  By calling
+.B readdir_do_ftype(0)
+one can ensure that the file type
+information is never displayed, even when readily available in the
+directory entry.
 .SH NOTES
 On GNU/Linux systems, there are filesystems that don't support the
 .B d_type
@@ -57,7 +61,7 @@ entry (see
 and so the file type is always
 .BR u .
 Therefore, using
-.B readdir_do_ftype(1)
+.B readdir_do_ftype(2)
 is advisable even on GNU/Linux systems. In this case, the
 .I readdir
 extension will fall back to using
diff --git a/extension/readdir.c b/extension/readdir.c
index 220d1725..14039c8b 100644
--- a/extension/readdir.c
+++ b/extension/readdir.c
@@ -62,7 +62,18 @@ static awk_bool_t (*init_func)(void) = init_readdir;
 
 int plugin_is_GPL_compatible;
 
-static int do_ftype;
+/*
+ * ftype <= 0: never return file type info
+ * ftype == 1: return file type info only if it is available in dirent
+ * ftype >= 2: always return file type info, calling fstat if necessary
+ */
+static int do_ftype =
+#ifdef DT_BLK
+	1
+#else
+	0
+#endif
+	;
 
 /* ftype --- return type of file as a single character string */
 
@@ -91,7 +102,15 @@ ftype(struct dirent *entry)
 	}
 #endif
 
-	if (! do_ftype || lstat(entry->d_name, & sbuf) < 0)
+	if (do_ftype < 2)
+		/*
+		 * Avoid "/u" since user did not insist on file type info,
+		 * and it does not seem to be supported by dirent on this
+		 * filesystem.
+		 */
+		return NULL;
+
+	if (lstat(entry->d_name, & sbuf) < 0)
 		return "u";
 
 	switch (sbuf.st_mode & S_IFMT) {
@@ -157,8 +176,11 @@ dir_get_record(char **out, struct iobuf_public *iobuf, int *errcode,
 	len = sprintf(the_dir->buf, "%llu/%s",
 			(unsigned long long) dirent->d_ino,
 			dirent->d_name);
-	if (do_ftype)
-		len += sprintf(the_dir->buf + len, "/%s", ftype(dirent));
+	if (do_ftype > 0) {
+		const char *ftstr = ftype(dirent);
+		if (ftstr)
+			len += sprintf(the_dir->buf + len, "/%s", ftstr);
+	}
 
 	*out = the_dir->buf;
 
@@ -286,7 +308,7 @@ do_readdir_do_ftype(int nargs, awk_value_t *result)
 		goto out;
 	}
 
-	do_ftype = (flag.num_value != 0.0);
+	do_ftype = flag.num_value;
 
 out:
 	return result;
diff --git a/test/readdir.awk b/test/readdir.awk
index 4d35be6a..3ec664df 100644
--- a/test/readdir.awk
+++ b/test/readdir.awk
@@ -1,7 +1,7 @@
 @load "readdir"
 
 BEGIN {
-	readdir_do_ftype(1)
+	readdir_do_ftype(2)
 }
 
 { print }