Make fuse_main_real() not symboled

Addresses https://github.com/libfuse/libfuse/issues/1092

We actually don't need to make fuse_main_real() symboled, as it
is not part of the official API.

The inlined function now always calls into fuse_main_real_317
and the compat ABI function (which should also be available
for dlopen/dlsym) is now always compiled, independent if the
compiler/linker support versioned symbols.

Additionally, fuse_main_real() is also declared as inlined
function and a warning message is created when that function
is called.

Signed-off-by: Bernd Schubert <bernd@bsbernd.com>

4 files changed, 45 insertions, 29 deletions

diff --git a/include/fuse.h b/include/fuse.h
index c3add84..969ed97 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -877,21 +877,32 @@ struct fuse_context {
 	mode_t umask;
 };
 
-#if (defined(LIBFUSE_BUILT_WITH_VERSIONED_SYMBOLS))
 /**
  * The real main function
  *
  * Do not call this directly, use fuse_main()
  */
-int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
-		   size_t op_size, struct libfuse_version *version,
-		   void *user_data);
-#else
-int fuse_main_real_317(int argc, char *argv[], const struct fuse_operations *op,
-		   size_t op_size, struct libfuse_version *version, void *user_data);
-#define fuse_main_real(argc, argv, op, op_size, version, user_data) \
-	fuse_main_real_317(argc, argv, op, op_size, version, user_data);
-#endif
+static inline int fuse_main_real(int argc, char *argv[],
+				 const struct fuse_operations *op,
+				 size_t op_size, void *user_data)
+{
+	struct libfuse_version version = { .major = FUSE_MAJOR_VERSION,
+					   .minor = FUSE_MINOR_VERSION,
+					   .hotfix = FUSE_HOTFIX_VERSION,
+					   .padding = 0 };
+
+	fuse_log(FUSE_LOG_ERR,
+		 "%s is a libfuse internal function, please use fuse_main()\n",
+		 __func__);
+
+	/* not declared globally, to restrict usage of this function */
+	int fuse_main_real_317(int argc, char *argv[],
+			       const struct fuse_operations *op, size_t op_size,
+			       struct libfuse_version *version,
+			       void *user_data);
+
+	return fuse_main_real_317(argc, argv, op, op_size, &version, user_data);
+}
 
 /**
  * Main function of FUSE.
@@ -957,8 +968,14 @@ fuse_main(int argc, char *argv[], const struct fuse_operations *op,
 		.hotfix = FUSE_HOTFIX_VERSION,
 		.padding = 0
 	};
-	return fuse_main_real(argc, argv, op, sizeof(*(op)), &version,
-			      user_data);
+
+	/* not declared globally, to restrict usage of this function */
+	int fuse_main_real_317(int argc, char *argv[],
+			       const struct fuse_operations *op, size_t op_size,
+			       struct libfuse_version *version,
+			       void *user_data);
+	return fuse_main_real_317(argc, argv, op, sizeof(*(op)), &version,
+				  user_data);
 }
 
 /* ----------------------------------------------------------- *
diff --git a/lib/compat.c b/lib/compat.c
index ce8a933..6852299 100644
--- a/lib/compat.c
+++ b/lib/compat.c
@@ -18,6 +18,7 @@
 #include "libfuse_config.h"
 
 #include <stddef.h>
+#include <stdint.h>
 
 struct fuse_args;
 struct fuse_cmdline_opts;
@@ -59,16 +60,6 @@ int fuse_session_custom_io(struct fuse_session *se,
 	return fuse_session_custom_io_30(se, io, fd);
 }
 
-int fuse_main_real_30(int argc, char *argv[], const struct fuse_operations *op,
-		      size_t op_size, void *user_data);
-int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
-		   size_t op_size, void *user_data);
-int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
-		   size_t op_size, void *user_data)
-{
-	return fuse_main_real_30(argc, argv, op, op_size, user_data);
-}
-
 struct fuse_session *fuse_session_new_30(struct fuse_args *args,
 					 const struct fuse_lowlevel_ops *op,
 					 size_t op_size, void *userdata);
@@ -82,6 +73,14 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
 	return fuse_session_new_30(args, op, op_size, userdata);
 }
 
-#endif
-
+#endif /* LIBFUSE_BUILT_WITH_VERSIONED_SYMBOLS */
 
+int fuse_main_real_30(int argc, char *argv[], const struct fuse_operations *op,
+		      size_t op_size, void *user_data);
+int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
+		   size_t op_size, void *user_data);
+int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
+		   size_t op_size, void *user_data)
+{
+	return fuse_main_real_30(argc, argv, op, op_size, user_data);
+}
diff --git a/lib/fuse_versionscript b/lib/fuse_versionscript
index f20e2b4..78df3f0 100644
--- a/lib/fuse_versionscript
+++ b/lib/fuse_versionscript
@@ -189,10 +189,10 @@ FUSE_3.12 {
 
 FUSE_3.17 {
 	global:
+		fuse_main_real_317;
 #if !defined(LIBFUSE_BUILT_WITH_VERSIONED_SYMBOLS)
 		_fuse_session_new_317;
 		_fuse_new_317;
-		fuse_main_real_317;
 #endif
 		fuse_passthrough_open;
 		fuse_passthrough_close;
diff --git a/lib/helper.c b/lib/helper.c
index 2794e66..660f029 100644
--- a/lib/helper.c
+++ b/lib/helper.c
@@ -304,9 +304,10 @@ int fuse_daemonize(int foreground)
 	return 0;
 }
 
+/* Not symboled, as not part of the official API */
 int fuse_main_real_317(int argc, char *argv[], const struct fuse_operations *op,
-		   size_t op_size, struct libfuse_version *version, void *user_data);
-FUSE_SYMVER("fuse_main_real_317", "fuse_main_real@@FUSE_3.17")
+		       size_t op_size, struct libfuse_version *version,
+		       void *user_data);
 int fuse_main_real_317(int argc, char *argv[], const struct fuse_operations *op,
 		   size_t op_size, struct libfuse_version *version, void *user_data)
 {
@@ -400,14 +401,13 @@ out1:
 	return res;
 }
 
+/* Not symboled, as not part of the official API */
 int fuse_main_real_30(int argc, char *argv[], const struct fuse_operations *op,
 		      size_t op_size, void *user_data);
-FUSE_SYMVER("fuse_main_real_30", "fuse_main_real@FUSE_3.0")
 int fuse_main_real_30(int argc, char *argv[], const struct fuse_operations *op,
 		      size_t op_size, void *user_data)
 {
 	struct libfuse_version version = { 0 };
-
 	return fuse_main_real_317(argc, argv, op, op_size, &version, user_data);
 }