chunk: Use dynamically allocated buffer in chunk_from_fd()

When acting on files, we can use fstat() to estimate the buffer size. On
non-file FDs, we dynamically increase an allocated buffer.

Additionally we slightly change the function signature to properly handle
zero-length files and add appropriate unit tests.

src/libstrongswan/tests/suites/test_chunk.c

@@ -17,8 +17,13 @@
 #include "test_suite.h"
 
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
 
 #include <utils/chunk.h>
+#include <threading/thread.h>
 
 /*******************************************************************************
  * utilities
@@ -812,6 +817,79 @@ START_TEST(test_chunk_map)
 }
 END_TEST
 
+/*******************************************************************************
+ * test for chunk_from_fd
+ */
+
+START_TEST(test_chunk_from_fd_file)
+{
+	chunk_t in, contents = chunk_from_chars(0x01,0x02,0x03,0x04,0x05);
+	char *path = "/tmp/strongswan-chunk-fd-test";
+	int fd;
+
+	ck_assert(chunk_write(contents, path, "chunk_fd", 022, TRUE));
+
+	fd = open(path, O_RDONLY);
+	ck_assert(fd != -1);
+
+	ck_assert(chunk_from_fd(fd, &in));
+	close(fd);
+	ck_assert_msg(chunk_equals(in, contents), "%B", &in);
+	unlink(path);
+	free(in.ptr);
+}
+END_TEST
+
+START_TEST(test_chunk_from_fd_skt)
+{
+	chunk_t in, contents = chunk_from_chars(0x01,0x02,0x03,0x04,0x05);
+	int s[2];
+
+	ck_assert(socketpair(AF_UNIX, SOCK_STREAM, 0, s) == 0);
+	ck_assert(write(s[1], contents.ptr, contents.len) == contents.len);
+	close(s[1]);
+	ck_assert_msg(chunk_from_fd(s[0], &in), "%s", strerror(errno));
+	close(s[0]);
+	ck_assert_msg(chunk_equals(in, contents), "%B", &in);
+	free(in.ptr);
+}
+END_TEST
+
+#define FROM_FD_COUNT 8192
+
+void *chunk_from_fd_run(void *data)
+{
+	int i, fd = (uintptr_t)data;
+
+	for (i = 0; i < FROM_FD_COUNT; i++)
+	{
+		ck_assert(write(fd, &i, sizeof(i)) == sizeof(i));
+	}
+	close(fd);
+	return NULL;
+}
+
+START_TEST(test_chunk_from_fd_huge)
+{
+	thread_t *thread;
+	chunk_t in;
+	int s[2], i;
+
+	ck_assert(socketpair(AF_UNIX, SOCK_STREAM, 0, s) == 0);
+
+	thread = thread_create(chunk_from_fd_run, (void*)(uintptr_t)s[1]);
+	ck_assert_msg(chunk_from_fd(s[0], &in), "%s", strerror(errno));
+	ck_assert_int_eq(in.len, FROM_FD_COUNT * sizeof(i));
+	for (i = 0; i < FROM_FD_COUNT; i++)
+	{
+		ck_assert_int_eq(((int*)in.ptr)[i], i);
+	}
+	thread->join(thread);
+	close(s[0]);
+	free(in.ptr);
+}
+END_TEST
+
 /*******************************************************************************
  * printf_hook tests
  */
@@ -933,6 +1011,12 @@ Suite *chunk_suite_create()
 	tcase_add_test(tc, test_chunk_map);
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("chunk_from_fd");
+	tcase_add_test(tc, test_chunk_from_fd_file);
+	tcase_add_test(tc, test_chunk_from_fd_skt);
+	tcase_add_test(tc, test_chunk_from_fd_huge);
+	suite_add_tcase(s, tc);
+
 	tc = tcase_create("printf_hook");
 	tcase_add_loop_test(tc, test_printf_hook_hash, 0, countof(printf_hook_data));
 	tcase_add_loop_test(tc, test_printf_hook_plus, 0, countof(printf_hook_data));