Fix EOF handling of __archive_read_ahead (#2196)

Reaching EOF for first time sets the correct amount of available bytes,
but each subsequent call returns 0.

Do not forget that the copy buffer can already contain data and return
the amount of bytes left in there.

See added test case.

diff --git a/Makefile.am b/Makefile.am
index 8a53329141f37773a6b3b64fb68f3a6447f13bd7..eb88654fce7d11686335609756520853894284ec 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -380,6 +380,7 @@ libarchive_test_SOURCES= \
        libarchive/test/test_archive_match_path.c \
        libarchive/test/test_archive_match_time.c \
        libarchive/test/test_archive_pathmatch.c \
+       libarchive/test/test_archive_read.c \
        libarchive/test/test_archive_read_add_passphrase.c \
        libarchive/test/test_archive_read_close_twice.c \
        libarchive/test/test_archive_read_close_twice_open_fd.c \

diff --git a/libarchive/archive_private.h b/libarchive/archive_private.h
index 0f05169b7d25b26169657af4bfcef8689a8abf09..5c5b5607aea2b168a99b568d8d353cd229341e3c 100644 (file)
--- a/libarchive/archive_private.h
+++ b/libarchive/archive_private.h
@@ -27,8 +27,10 @@
 #define ARCHIVE_PRIVATE_H_INCLUDED
 
 #ifndef __LIBARCHIVE_BUILD
+#ifndef __LIBARCHIVE_TEST
 #error This header is only to be used internally to libarchive.
 #endif
+#endif
 
 #if HAVE_ICONV_H
 #include <iconv.h>

diff --git a/libarchive/archive_read.c b/libarchive/archive_read.c
index d71fc2b7cc044ab2f90c09d66100567138ce5a9d..1fa35853c55837074221a6ca2371562f96ba5b9f 100644 (file)
--- a/libarchive/archive_read.c
+++ b/libarchive/archive_read.c
@@ -1382,7 +1382,7 @@ __archive_read_filter_ahead(struct archive_read_filter *filter,
                if (filter->client_avail <= 0) {
                        if (filter->end_of_file) {
                                if (avail != NULL)
-                                       *avail = 0;
+                                       *avail = filter->avail;
                                return (NULL);
                        }
                        bytes_read = (filter->vtable->read)(filter,

diff --git a/libarchive/test/CMakeLists.txt b/libarchive/test/CMakeLists.txt
index bef739ad47fb3ff98dfca5deaacbc64c7b7dd911..6d28fc904ae15bb180c2c8a8e1fc2cafc114a78a 100644 (file)
--- a/libarchive/test/CMakeLists.txt
+++ b/libarchive/test/CMakeLists.txt
@@ -24,6 +24,7 @@ IF(ENABLE_TEST)
     test_archive_match_path.c
     test_archive_match_time.c
     test_archive_pathmatch.c
+    test_archive_read.c
     test_archive_read_add_passphrase.c
     test_archive_read_close_twice.c
     test_archive_read_close_twice_open_fd.c

diff --git a/libarchive/test/test_archive_read.c b/libarchive/test/test_archive_read.c
new file mode 100644 (file)
index 0000000..583e516
--- /dev/null
+++ b/libarchive/test/test_archive_read.c
@@ -0,0 +1,63 @@
+/*-
+ * Copyright (c) 2024 Tobias Stoeckmann
+ * 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"
+
+#define __LIBARCHIVE_TEST
+#include "archive_read_private.h"
+
+static char buf[1024];
+
+DEFINE_TEST(test_archive_read_ahead_eof)
+{
+       struct archive *a;
+       struct archive_read *ar;
+       ssize_t avail;
+
+       /* prepare a reader of raw in-memory data */
+       assert((a = archive_read_new()) != NULL);
+       ar = (struct archive_read *)a;
+
+       assertA(0 == archive_read_support_format_raw(a));
+       assertA(0 == archive_read_open_memory(a, buf, sizeof(buf)));
+
+       /* perform a read which can be fulfilled */
+       assert(NULL != __archive_read_ahead(ar, sizeof(buf) - 1, &avail));
+       assertEqualInt(sizeof(buf), avail);
+
+       /* perform a read which cannot be fulfilled due to EOF */
+       assert(NULL == __archive_read_ahead(ar, sizeof(buf) + 1, &avail));
+       assertEqualInt(sizeof(buf), avail);
+
+       /* perform the same read again */
+       assert(NULL == __archive_read_ahead(ar, sizeof(buf) + 1, &avail));
+       assertEqualInt(sizeof(buf), avail);
+
+       /* perform another read which can be fulfilled */
+       assert(NULL != __archive_read_ahead(ar, sizeof(buf), &avail));
+       assertEqualInt(sizeof(buf), avail);
+
+       assert(0 == archive_read_free(a));
+}