grub-mount: Add support for libfuse3

The libfuse 3.0.0 got released in 2016, with some API changes compared to 2.x.
This commit introduces support for 3.x while keeping it compatible with 2.6
as a fallback still.

To detect fuse3, switch configure over to use pkg-config, which is simpler yet
more reliable than looking for library and header manually. Also set
FUSE_USE_VERSION that way, as it depends on the used libfuse version.

Now that the CFLAGS are read from pkg-config, use just <fuse.h>, which works
with 2.x as well as 3.x and is recommended by libfuse upstream.

One behavior change of libfuse3 is that FUSE_ATOMIC_O_TRUNC is set by default,
which means that open with O_TRUNC is passed as-is instead of calling the
truncate operation. With libfuse2, truncate failed with -ENOSYS and that was
returned to the application. To make O_TRUNC fail with libfuse3, return -EROFS
explicitly if writing was requested.

Signed-off-by: Fabian Vogt <fvogt@suse.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Fabian Vogt 2022-01-17 15:34:37 +01:00 committed by Daniel Kiper
parent 91803b0a1b
commit a385f10480
3 changed files with 30 additions and 15 deletions

View File

@ -309,11 +309,13 @@ program = {
common = grub-core/disk/host.c;
common = grub-core/osdep/init.c;
cflags = '$(FUSE_CFLAGS)';
ldadd = libgrubmods.a;
ldadd = libgrubgcry.a;
ldadd = libgrubkern.a;
ldadd = grub-core/lib/gnulib/libgnu.a;
ldadd = '$(LIBINTL) $(LIBDEVMAPPER) $(LIBZFS) $(LIBNVPAIR) $(LIBGEOM) -lfuse';
ldadd = '$(LIBINTL) $(LIBDEVMAPPER) $(LIBZFS) $(LIBNVPAIR) $(LIBGEOM) $(FUSE_LIBS)';
condition = COND_GRUB_MOUNT;
};

View File

@ -1797,17 +1797,11 @@ if test x"$enable_grub_mount" = xno ; then
fi
if test x"$grub_mount_excuse" = x ; then
AC_CHECK_LIB([fuse], [fuse_main_real], [],
[grub_mount_excuse="need FUSE library"])
fi
if test x"$grub_mount_excuse" = x ; then
# Check for fuse headers.
SAVED_CPPFLAGS="$CPPFLAGS"
CPPFLAGS="$CPPFLAGS -DFUSE_USE_VERSION=26"
AC_CHECK_HEADERS([fuse/fuse.h], [],
[grub_mount_excuse=["need FUSE headers"]])
CPPFLAGS="$SAVED_CPPFLAGS"
PKG_CHECK_MODULES([FUSE], [fuse3], [FUSE_CFLAGS="$FUSE_CFLAGS -DFUSE_USE_VERSION=32"], [
PKG_CHECK_MODULES([FUSE], [fuse], [FUSE_CFLAGS="$FUSE_CFLAGS -DFUSE_USE_VERSION=26"], [
grub_mount_excuse="need fuse or fuse3 libraries"
])
])
fi
if test x"$enable_grub_mount" = xyes && test x"$grub_mount_excuse" != x ; then

View File

@ -16,7 +16,6 @@
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#define FUSE_USE_VERSION 26
#include <config.h>
#include <grub/types.h>
#include <grub/emu/misc.h>
@ -34,7 +33,7 @@
#include <grub/command.h>
#include <grub/zfs/zfs.h>
#include <grub/i18n.h>
#include <fuse/fuse.h>
#include <fuse.h>
#include <stdio.h>
#include <unistd.h>
@ -146,8 +145,14 @@ fuse_getattr_find_file (const char *cur_filename,
return 0;
}
#if FUSE_USE_VERSION < 30
static int
fuse_getattr (const char *path, struct stat *st)
#else
static int
fuse_getattr (const char *path, struct stat *st,
struct fuse_file_info *fi __attribute__ ((unused)))
#endif
{
struct fuse_getattr_ctx ctx;
char *pathname, *path2;
@ -241,8 +246,11 @@ static grub_file_t files[65536];
static int first_fd = 1;
static int
fuse_open (const char *path, struct fuse_file_info *fi __attribute__ ((unused)))
fuse_open (const char *path, struct fuse_file_info *fi)
{
if ((fi->flags & O_ACCMODE) != O_RDONLY)
return -EROFS;
grub_file_t file;
file = grub_file_open (path, GRUB_FILE_TYPE_MOUNT);
if (! file)
@ -330,13 +338,24 @@ fuse_readdir_call_fill (const char *filename,
st.st_blocks = (st.st_size + 511) >> 9;
st.st_atime = st.st_mtime = st.st_ctime
= info->mtimeset ? info->mtime : 0;
#if FUSE_USE_VERSION < 30
ctx->fill (ctx->buf, filename, &st, 0);
#else
ctx->fill (ctx->buf, filename, &st, 0, 0);
#endif
return 0;
}
#if FUSE_USE_VERSION < 30
static int
fuse_readdir (const char *path, void *buf,
fuse_fill_dir_t fill, off_t off, struct fuse_file_info *fi)
#else
static int
fuse_readdir (const char *path, void *buf,
fuse_fill_dir_t fill, off_t off, struct fuse_file_info *fi,
enum fuse_readdir_flags flags __attribute__ ((unused)))
#endif
{
struct fuse_readdir_ctx ctx = {
.path = path,