Add ssh_callbacks_exists internal macro + unittest

(first commit with eclipse helios, crossing fingers ...)

include/libssh/callbacks.h

@@ -156,7 +156,8 @@ typedef struct ssh_socket_callbacks_struct *ssh_socket_callbacks;
 #define SSH_SOCKET_CONNECTED_ERROR 		2
 #define SSH_SOCKET_CONNECTED_TIMEOUT 	3
 
-/** Initializes an ssh_callbacks_struct
+/**
+ * @brief Initializes an ssh_callbacks_struct
  * A call to this macro is mandatory when you have set a new
  * ssh_callback_struct structure. Its goal is to maintain the binary
  * compatibility with future versions of libssh as the structure
@@ -166,6 +167,20 @@ typedef struct ssh_socket_callbacks_struct *ssh_socket_callbacks;
 	(p)->size=sizeof(*(p)); \
 } while(0);
 
+/**
+ * @internal
+ * @brief tests if a callback can be called without crash
+ *  verifies that the struct size if big enough
+ *  verifies that the callback pointer exists
+ * @param p callback pointer
+ * @param c callback name
+ * @returns nonzero if callback can be called
+ */
+#define ssh_callbacks_exists(p,c) (\
+  ( (char *)&((p)-> c) < (char *)(p) + (p)->size ) && \
+  ((p)-> c != NULL) \
+  )
+
 /** @brief Prototype for a packet callback, to be called when a new packet arrives
  * @param session The current session of the packet
  * @param type packet type (see ssh2.h)
@@ -217,11 +232,10 @@ typedef struct ssh_packet_callbacks_struct *ssh_packet_callbacks;
  * functions for auth, logging and status.
  *
  * @code
- * struct ssh_callbacks_struct cb;
- * memset(&cb, 0, sizeof(struct ssh_callbacks_struct));
- * cb.userdata = data;
- * cb.auth_function = my_auth_function;
- *
+ * struct ssh_callbacks_struct cb = {
+ *   .userdata = data,
+ *   .auth_function = my_auth_function
+ * };
  * ssh_callbacks_init(&cb);
  * ssh_set_callbacks(session, &cb);
  * @endcode

tests/unittests/CMakeLists.txt

@@ -1,8 +1,9 @@
 project(unittests C)
 
+add_check_test(torture_callbacks torture_callbacks.c ${TORTURE_LIBRARY})
 add_check_test(torture_init torture_init.c ${TORTURE_LIBRARY})
+add_check_test(torture_keyfiles torture_keyfiles.c ${TORTURE_LIBRARY})
+add_check_test(torture_knownhosts torture_knownhosts.c ${TORTURE_LIBRARY})
 add_check_test(torture_list torture_list.c ${TORTURE_LIBRARY})
 add_check_test(torture_misc torture_misc.c ${TORTURE_LIBRARY})
-add_check_test(torture_keyfiles torture_keyfiles.c ${TORTURE_LIBRARY})
 add_check_test(torture_options torture_options.c ${TORTURE_LIBRARY})
-add_check_test(torture_knownhosts torture_knownhosts.c ${TORTURE_LIBRARY})

tests/unittests/torture_callbacks.c

@@ -0,0 +1,61 @@
+#define LIBSSH_STATIC
+
+#include "torture.h"
+#include <libssh/priv.h>
+#include <libssh/callbacks.h>
+
+static int myauthcallback (const char *prompt, char *buf, size_t len,
+    int echo, int verify, void *userdata){
+	(void) prompt;
+	(void) buf;
+	(void) len;
+	(void) echo;
+	(void) verify;
+	(void) userdata;
+	return 0;
+}
+
+struct ssh_callbacks_struct callbacks =
+{
+		.userdata=(void *)0x0badc0de,
+		.auth_function=myauthcallback
+};
+
+static void setup(void) {
+	ssh_callbacks_init(&callbacks);
+}
+
+static void teardown(void) {
+
+}
+
+START_TEST (torture_callbacks_size)
+{
+	ck_assert_int_ne(callbacks.size,0);
+}
+END_TEST
+
+START_TEST (torture_callbacks_exists)
+{
+	ck_assert_int_ne(ssh_callbacks_exists(&callbacks,auth_function),0);
+	ck_assert_int_eq(ssh_callbacks_exists(&callbacks,log_function),0);
+	/* we redefine size so auth_function is outside the range of callbacks->size */
+  callbacks.size=(unsigned char *)&(callbacks.auth_function) - (unsigned char *)&callbacks;
+  ck_assert_int_eq(ssh_callbacks_exists(&callbacks,auth_function),0);
+  /* now make it one pointer bigger so we spill over the auth_function slot */
+  callbacks.size += sizeof(void *);
+  ck_assert_int_ne(ssh_callbacks_exists(&callbacks,auth_function),0);
+}
+END_TEST
+
+Suite *torture_make_suite(void) {
+  Suite *s = suite_create("libssh_options");
+
+  torture_create_case_fixture(s, "torture_callbacks_size",
+          torture_callbacks_size, setup, teardown);
+  torture_create_case_fixture(s, "torture_callbacks_exists",
+          torture_callbacks_exists, setup, teardown);
+
+  return s;
+}
+