This is a preperatory patch to move things around to be ready for supporting the low-level FUSE API:

It introduces the following new files.

- /usr/include/fuse/fuse_common.h
- /usr/include/fuse/fuse_lowlevel.h
- /usr/src/lib/libfuse/fuse_chan.c

Additionally, it relocates all libfuse header files to the
/usr/include/fuse directory so that it now contains.

- /usr/include/fuse/fuse.h
- /usr/include/fuse/fuse_opt.h
- /usr/include/fuse/fuse_common.h
- /usr/include/fuse/fuse_lowlevel.h

Relevant definitions have been moved into their appropriate
files, and I took the opportunity for some minor cleanup. The
pkg-config metadata has also been updated to reflect the new header
locations.

ok claudio@ sthen@

lib/libfuse/Makefile

···
-#	$OpenBSD: Makefile,v 1.17 2018/11/28 21:19:11 mpi Exp $
+#	$OpenBSD: Makefile,v 1.18 2025/12/08 06:37:04 helg Exp $
 
 LIB=	fuse
 MAN=	fuse_chan_fd.3 fuse_daemonize.3 fuse_destroy.3 fuse_get_context.3 \
···
 # XXX Shouldn't we use a common fuse.h with proper ifdef _KERNEL part?
 CFLAGS+=	-I${.CURDIR}
 
-SRCS=	debug.c dict.c fuse.c fuse_ops.c fuse_opt.c fuse_subr.c tree.c
-HDRS=	fuse.h fuse_opt.h
+SRCS=	debug.c dict.c fuse.c fuse_ops.c fuse_opt.c fuse_subr.c tree.c \
+	fuse_chan.c
+HDRS=	fuse.h fuse_opt.h fuse_common.h fuse_lowlevel.h
 
 VERSION_SCRIPT=	${.CURDIR}/Symbols.map
 
···
 CLEANFILES+=${PC_FILES}
 
 includes:
+	${INSTALL} -d -o ${BINOWN} -g ${BINGRP} -m 755 \
+	    ${DESTDIR}/usr/include/fuse
 	@cd ${.CURDIR}; for i in ${HDRS}; do \
-		j="cmp -s $$i ${DESTDIR}/usr/include/$$i || \
+		j="cmp -s $$i ${DESTDIR}/usr/include/fuse/$$i || \
 		    ${INSTALL} ${INSTALL_COPY} -o ${BINOWN} -g ${BINGRP} -m 444 \
-	            $$i ${DESTDIR}/usr/include"; \
+	            $$i ${DESTDIR}/usr/include/fuse"; \
 	        echo $$j; \
 	        eval "$$j"; \
 	done

lib/libfuse/fuse.c

···
-/* $OpenBSD: fuse.c,v 1.56 2025/11/19 08:19:18 helg Exp $ */
+/* $OpenBSD: fuse.c,v 1.57 2025/12/08 06:37:04 helg Exp $ */
 /*
  * Copyright (c) 2013 Sylvestre Gallon <[e-mail]>
  *
···
 #include <string.h>
 #include <unistd.h>
 
-#include "fuse_opt.h"
 #include "fuse_private.h"
 #include "debug.h"
 
···
 {
 	return (fuse_opt_match(fuse_lib_opts, opt));
 }
-
-int
-fuse_chan_fd(struct fuse_chan *ch)
-{
-	if (ch == NULL)
-		return (-1);
-
-	return (ch->fd);
-}
+DEF(fuse_is_lib_option);
 
 struct fuse_session *
 fuse_get_session(struct fuse *f)
···
 {
 	return (-1);
 }
+DEF(fuse_loop_mt);
 
 static int
 ifuse_lib_opt_proc(void *data, const char *arg, int key,
···
 
 	return (0);
 }
+DEF(fuse_set_signal_handlers);
 
 static void
 dump_help(void)
···
 {
 	return (FUSE_VERSION);
 }
+DEF(fuse_version);
 
 void
 fuse_teardown(struct fuse *fuse, char *mp)
···
 	fuse_unmount(mp, fuse->fc);
 	fuse_destroy(fuse);
 }
+DEF(fuse_teardown);
 
 int
 fuse_invalidate(unused struct fuse *f, unused const char *path)
 {
 	return (EINVAL);
 }
+DEF(fuse_invalidate);
 
 struct fuse *
 fuse_setup(int argc, char **argv, const struct fuse_operations *ops,
···
 
 	return (ret == -1 ? 1 : 0);
 }
+DEF(fuse_main);

lib/libfuse/fuse.h

···
-/* $OpenBSD: fuse.h,v 1.14 2018/05/16 13:09:17 helg Exp $ */
+/* $OpenBSD: fuse.h,v 1.15 2025/12/08 06:37:04 helg Exp $ */
 /*
  * Copyright (c) 2013 Sylvestre Gallon <[e-mail]>
  *
···
 #ifndef _FUSE_H_
 #define _FUSE_H_
 
-#include <sys/types.h>
+#ifndef FUSE_USE_VERSION
+#define FUSE_USE_VERSION 26
+#endif
+
 #include <sys/stat.h>
 #include <sys/statvfs.h>
 
 #include <fcntl.h>
 #include <utime.h>
 
-#include <fuse_opt.h>
+#include "fuse_common.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-struct fuse_chan;
-struct fuse_args;
-struct fuse_session;
-
-struct fuse_file_info {
-	int32_t		flags;		/* open(2) flags */
-	uint32_t	fh_old;		/* old file handle */
-	int32_t		writepage;
-	uint32_t	direct_io:1;
-	uint32_t	keep_cache:1;
-	uint32_t	flush:1;
-	uint32_t	nonseekable:1;
-	uint32_t	__padd:27;
-	uint32_t	flock_release : 1;
-	uint64_t	fh;		/* file handle */
-	uint64_t	lock_owner;
-};
-
-/* unused but needed for gvfs compilation */
-#define FUSE_CAP_ASYNC_READ	(1 << 0)
-#define FUSE_CAP_POSIX_LOCKS	(1 << 1)
-#define FUSE_CAP_ATOMIC_O_TRUNC	(1 << 3)
-#define FUSE_CAP_EXPORT_SUPPORT	(1 << 4)
-#define FUSE_CAP_BIG_WRITES	(1 << 5)
-#define FUSE_CAP_DONT_MASK	(1 << 6)
-#define FUSE_CAP_SPLICE_WRITE	(1 << 7)
-#define FUSE_CAP_SPLICE_MOVE	(1 << 8)
-#define FUSE_CAP_SPLICE_READ	(1 << 9)
-#define FUSE_CAP_FLOCK_LOCKS	(1 << 10)
-#define FUSE_CAP_IOCTL_DIR	(1 << 11)
-
-struct fuse_conn_info {
-	uint32_t	proto_major;
-	uint32_t	proto_minor;
-	uint32_t	async_read;
-	uint32_t	max_write;
-	uint32_t	max_readahead;
-	uint32_t	capable;
-	uint32_t	want;
-	uint32_t	max_background;
-	uint32_t	congestion_threshold;
-	uint32_t	reserved[23];
-};
-
 struct fuse_context {
 	struct fuse *	fuse;
 	uid_t		uid;
···
 	mode_t		umask;
 };
 
-typedef ino_t fuse_ino_t;
 typedef int (*fuse_fill_dir_t)(void *, const char *, const struct stat *,
     off_t);
 
 typedef struct fuse_dirhandle *fuse_dirh_t;
 typedef int (*fuse_dirfil_t)(fuse_dirh_t, const char *, int, ino_t);
 
-/* 
+/*
  * Fuse operations work in the same way as their UNIX file system
  * counterparts. A major exception is that these routines return
  * a negated errno value (-errno) on failure.
···
 	int	(*access)(const char *, int);
 	int	(*create)(const char *, mode_t, struct fuse_file_info *);
 	int	(*ftruncate)(const char *, off_t, struct fuse_file_info *);
-	int	(*fgetattr)(const char *, struct stat *, struct fuse_file_info *);
-	int	(*lock)(const char *, struct fuse_file_info *, int, struct flock *);
+	int	(*fgetattr)(const char *, struct stat *,
+		struct fuse_file_info *);
+	int	(*lock)(const char *, struct fuse_file_info *, int,
+		struct flock *);
 	int	(*utimens)(const char *, const struct timespec *);
 	int	(*bmap)(const char *, size_t , uint64_t *);
 };
 
-#ifndef FUSE_USE_VERSION
-#define FUSE_USE_VERSION 26
-#endif
-
-#if FUSE_USE_VERSION >= 26
-#define FUSE_VERSION 26
-#else
-#error "Fuse version < 26 not supported"
-#endif
-
-#define	FUSE_MAJOR_VERSION 2
-#define	FUSE_MINOR_VERSION 6
-
 /*
  * API prototypes
  */
-int fuse_version(void);
 int fuse_main(int, char **, const struct fuse_operations *, void *);
 struct fuse *fuse_new(struct fuse_chan *, struct fuse_args *,
     const struct fuse_operations *, size_t, void *);
 struct fuse *fuse_setup(int, char **, const struct fuse_operations *,
     size_t, char **, int *, void *);
-int fuse_parse_cmdline(struct fuse_args *, char **, int *, int *);
-struct fuse_chan *fuse_mount(const char *, struct fuse_args *);
-void fuse_remove_signal_handlers(struct fuse_session *);
-int fuse_set_signal_handlers(struct fuse_session *);
 struct fuse_session *fuse_get_session(struct fuse *);
 struct fuse_context *fuse_get_context(void);
-int fuse_is_lib_option(const char *);
 int fuse_loop(struct fuse *);
 int fuse_loop_mt(struct fuse *);
-int fuse_chan_fd(struct fuse_chan *);
-void fuse_unmount(const char *, struct fuse_chan *);
-int fuse_daemonize(int);
 void fuse_destroy(struct fuse *);
 void fuse_teardown(struct fuse *, char *);
+
+/* Obsolete */
+int fuse_is_lib_option(const char *);
 int fuse_invalidate(struct fuse *, const char *);
 
 #ifdef __cplusplus

lib/libfuse/fuse_chan.c

···
+/* $OpenBSD: fuse_chan.c,v 1.1 2025/12/08 06:37:04 helg Exp $ */
+/*
+ * Copyright (c) 2025 Helg Bredow <[e-mail]>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "fuse_private.h"
+
+int
+fuse_chan_fd(struct fuse_chan *ch)
+{
+	if (ch == NULL)
+		return (-1);
+
+	return (ch->fd);
+}
+DEF(fuse_chan_fd);

lib/libfuse/fuse_common.h

···
+/* $OpenBSD: fuse_common.h,v 1.1 2025/12/08 06:37:04 helg Exp $ */
+/*
+ * Copyright (c) 2025 Helg Bredow <[e-mail]>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This file contains definitions common to both the low and high-level FUSE
+ * APIs.
+ */
+
+#if !defined(_FUSE_H_) && !defined(_FUSE_LOWLEVEL_H_)
+#error "Never include <fuse_common.h> directly; use <fuse.h> or <fuse_lowlevel.h> instead."
+#endif
+
+#ifndef _FUSE_COMMON_H_
+#define _FUSE_COMMON_H_
+
+#if FUSE_USE_VERSION >= 26
+#define FUSE_VERSION 26
+#else
+#error "Fuse version < 26 not supported"
+#endif
+
+#include <sys/types.h>
+#include <stdint.h>
+
+#include "fuse_opt.h"
+
+#define FUSE_MAJOR_VERSION 2
+#define FUSE_MINOR_VERSION 6
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct fuse_file_info {
+	int32_t		flags;		/* open(2) flags */
+	uint32_t	fh_old;		/* old file handle */
+	int32_t		writepage;
+	uint32_t	direct_io	: 1;
+	uint32_t	keep_cache	: 1;
+	uint32_t	flush		: 1;
+	uint32_t	nonseekable	: 1;
+	uint32_t	__padd		: 27;
+	uint32_t	flock_release	: 1;
+	uint64_t	fh;		/* file handle */
+	uint64_t	lock_owner;
+};
+
+/* unused but needed for gvfs compilation */
+#define FUSE_CAP_ASYNC_READ     (1 << 0)
+#define FUSE_CAP_POSIX_LOCKS    (1 << 1)
+#define FUSE_CAP_ATOMIC_O_TRUNC (1 << 3)
+#define FUSE_CAP_EXPORT_SUPPORT (1 << 4)
+#define FUSE_CAP_BIG_WRITES     (1 << 5)
+#define FUSE_CAP_DONT_MASK      (1 << 6)
+#define FUSE_CAP_SPLICE_WRITE   (1 << 7)
+#define FUSE_CAP_SPLICE_MOVE    (1 << 8)
+#define FUSE_CAP_SPLICE_READ    (1 << 9)
+#define FUSE_CAP_FLOCK_LOCKS    (1 << 10)
+#define FUSE_CAP_IOCTL_DIR      (1 << 11)
+
+struct fuse_conn_info {
+	uint32_t	proto_major;
+	uint32_t	proto_minor;
+	uint32_t	async_read;
+	uint32_t	max_write;
+	uint32_t	max_readahead;
+	uint32_t	capable;
+	uint32_t	want;
+	uint32_t	max_background;
+	uint32_t	congestion_threshold;
+	uint32_t	reserved[23];
+};
+
+struct fuse_chan;
+struct fuse_args;
+struct fuse_session;
+
+/*
+ * API prototypes
+ */
+int fuse_version(void);
+int fuse_parse_cmdline(struct fuse_args *, char **, int *, int *);
+int fuse_daemonize(int);
+int fuse_set_signal_handlers(struct fuse_session *);
+void fuse_unmount(const char *, struct fuse_chan *);
+void fuse_remove_signal_handlers(struct fuse_session *);
+struct fuse_chan *fuse_mount(const char *, struct fuse_args *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _FUSE_COMMON_H_ */

lib/libfuse/fuse_lowlevel.h

···
+/* $OpenBSD: fuse_lowlevel.h,v 1.1 2025/12/08 06:37:04 helg Exp $ */
+/*
+ * Copyright (c) 2025 Helg Bredow <[e-mail]>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _FUSE_LOWLEVEL_H_
+#define _FUSE_LOWLEVEL_H_
+
+#ifndef FUSE_USE_VERSION
+#define FUSE_USE_VERSION 26
+#endif
+
+#include <sys/stat.h>
+
+#include "fuse_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef ino_t fuse_ino_t;
+
+/*
+ * FUSE Channel API Prototypes
+ */
+int fuse_chan_fd(struct fuse_chan *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _FUSE_LOWLEVEL_H_ */

lib/libfuse/fuse_opt.c

···
-/* $OpenBSD: fuse_opt.c,v 1.27 2022/01/16 20:06:18 naddy Exp $ */
+/* $OpenBSD: fuse_opt.c,v 1.28 2025/12/08 06:37:05 helg Exp $ */
 /*
  * Copyright (c) 2013 Sylvestre Gallon <[e-mail]>
  * Copyright (c) 2013 Stefan Sperling <[e-mail]>
···
 	ret = add_opt(opts, opt);
 	return (ret);
 }
+DEF(fuse_opt_add_opt);
 
 int
 fuse_opt_add_opt_escaped(char **opts, const char *opt)
···
 	free(escaped_opt);
 	return (ret);
 }
+DEF(fuse_opt_add_opt_escaped);
 
 int
 fuse_opt_add_arg(struct fuse_args *args, const char *name)

lib/libfuse/fuse_private.h

···
-/* $OpenBSD: fuse_private.h,v 1.25 2025/11/19 08:19:18 helg Exp $ */
+/* $OpenBSD: fuse_private.h,v 1.26 2025/12/08 06:37:05 helg Exp $ */
 /*
  * Copyright (c) 2013 Sylvestre Gallon <[e-mail]>
  *
···
 #ifndef _FUSE_SUBR_H_
 #define _FUSE_SUBR_H_
 
+#include <sys/types.h>
 #include <sys/dirent.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
···
 #include <limits.h>
 
 #include "fuse.h"
-
-struct fuse_args;
+#include "fuse_lowlevel.h"
 
 struct fuse_vnode {
 	ino_t ino;
···
 #define	DEF(x)		__strong_alias(x, __##x)
 
 PROTO(fuse_daemonize);
+PROTO(fuse_teardown);
 PROTO(fuse_destroy);
 PROTO(fuse_get_context);
 PROTO(fuse_get_session);
 PROTO(fuse_loop);
+PROTO(fuse_loop_mt);
 PROTO(fuse_mount);
 PROTO(fuse_new);
 PROTO(fuse_opt_add_arg);
+PROTO(fuse_opt_add_opt);
+PROTO(fuse_opt_add_opt_escaped);
 PROTO(fuse_opt_free_args);
 PROTO(fuse_opt_insert_arg);
 PROTO(fuse_opt_match);
 PROTO(fuse_opt_parse);
 PROTO(fuse_parse_cmdline);
 PROTO(fuse_remove_signal_handlers);
+PROTO(fuse_set_signal_handlers);
 PROTO(fuse_setup);
 PROTO(fuse_unmount);
+PROTO(fuse_main);
+PROTO(fuse_version);
+PROTO(fuse_invalidate);
+PROTO(fuse_is_lib_option);
+
+/* FUSE low-level */
+PROTO(fuse_chan_fd);
 
 #endif /* _FUSE_SUBR_ */

lib/libfuse/generate_pkgconfig.sh

···
 #!/bin/sh
 #
-# $OpenBSD: generate_pkgconfig.sh,v 1.2 2013/06/15 11:40:56 jasper Exp $
+# $OpenBSD: generate_pkgconfig.sh,v 1.3 2025/12/08 06:37:05 helg Exp $
 #
 # Copyright (c) 2010,2011 Jasper Lievisse Adriaanse <[e-mail]>
 #
···
 prefix=/usr
 exec_prefix=\${prefix}
 libdir=\${exec_prefix}/lib
-includedir=\${prefix}/include
+includedir=\${prefix}/include/fuse
 
 Name: fuse
 Description: fuse filesystem library