Fix archive freeing bug in bsdcat.

(1) Do not double free a for the stdin case. Reported by Sean Purcell in
    PR #904.
(2) Do not query errors after archive_read_free either, the memory is
    gone. Split operation into close and read, reporting errors from the
    former.

3 files changed, 55 insertions, 5 deletions

diff --git a/cat/bsdcat.c b/cat/bsdcat.c
index 6ba10349..9c91d09c 100644
--- a/cat/bsdcat.c
+++ b/cat/bsdcat.c
@@ -70,6 +70,12 @@ version(void)
 void
 bsdcat_next(void)
 {
+	if (a != NULL) {
+		if (archive_read_close(a) != ARCHIVE_OK)
+			bsdcat_print_error();
+		archive_read_free(a);
+	}
+
 	a = archive_read_new();
 	archive_read_support_filter_all(a);
 	archive_read_support_format_empty(a);
@@ -100,8 +106,10 @@ bsdcat_read_to_stdout(const char* filename)
 		;
 	else if (archive_read_data_into_fd(a, 1) != ARCHIVE_OK)
 		bsdcat_print_error();
-	if (archive_read_free(a) != ARCHIVE_OK)
+	if (archive_read_close(a) != ARCHIVE_OK)
 		bsdcat_print_error();
+	archive_read_free(a);
+	a = NULL;
 }
 
 int
@@ -135,15 +143,14 @@ main(int argc, char **argv)
 	if (*bsdcat->argv == NULL) {
 		bsdcat_current_path = "<stdin>";
 		bsdcat_read_to_stdout(NULL);
-	} else
+	} else {
 		while (*bsdcat->argv) {
 			bsdcat_current_path = *bsdcat->argv++;
 			bsdcat_read_to_stdout(bsdcat_current_path);
 			bsdcat_next();
 		}
-
-	if (a != NULL)
-		archive_read_free(a);
+		archive_read_free(a); /* Help valgrind & friends */
+	}
 
 	exit(exit_status);
 }
diff --git a/cat/test/CMakeLists.txt b/cat/test/CMakeLists.txt
index 4652ff37..72f4a103 100644
--- a/cat/test/CMakeLists.txt
+++ b/cat/test/CMakeLists.txt
@@ -24,6 +24,7 @@ IF(ENABLE_CAT AND ENABLE_TEST)
     test_expand_xz.c
     test_expand_zstd.c
     test_help.c
+    test_stdin.c
     test_version.c
   )
 
diff --git a/cat/test/test_stdin.c b/cat/test/test_stdin.c
new file mode 100644
index 00000000..cea5eb0e
--- /dev/null
+++ b/cat/test/test_stdin.c
@@ -0,0 +1,42 @@
+/*-
+ * Copyright (c) 2017 Sean Purcell
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "test.h"
+
+#if !defined(_WIN32) || defined(__CYGWIN__)
+#define DEV_NULL "/dev/null"
+#else
+#define DEV_NULL "NUL"
+#endif
+
+DEFINE_TEST(test_stdin)
+{
+	int f;
+
+	f = systemf("%s <%s >test.out 2>test.err", testprog, DEV_NULL);
+	assertEqualInt(0, f);
+	assertEmptyFile("test.out");
+	assertEmptyFile("test.err");
+}
+