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2025-05-21conn->want conversion: Fix fuse_apply_conn_info_opts()Bernd Schubert-4/+11
fuse_apply_conn_info_opts() was applying to 'want_ext', which would cause conflicts with 'want' if the application applied its own flags to 'conn->want'. Solution is: - to move fuse_{set,unset,get}_feature_flag and convert_to_conn_want_ext() to fuse_lowlevel.c and to define them as part of the public API, although convert_to_conn_want_ext() should not be used - it is currently needed to be a public function due as it needs to be defined for the tests. Related to https://github.com/libfuse/libfuse/issues/1171 and https://github.com/libfuse/libfuse/pull/1172. Closes: https://github.com/libfuse/libfuse/issues/1171 Signed-off-by: Bernd Schubert <bschubert@ddn.com> (cherry picked from commit baadab0492a495fda98216b351976d2e5d6d0866)
2025-03-24fuse: Fix want flag conversionBernd Schubert-2/+2
32-bit conn->want flags been left to be ABI compatible to 3.10, even though the so version was changed. The more recent way is to use fuse_set_feature_flag(), which will use conn->want_ext. Given that we now have two flags (want and want_ext), we need to convert and that brought several issues - If the application sets conn->want, that needs to be set into the lower 32 bit of conn->want_ext. As the application might actually unset values, it really has to be a copy and not just 'or' - fixed now. - convert_to_conn_want_ext() actually needs to check for _modified_ conn->want and conn->want_ext - convert_to_conn_want_ext() must consider being called from high and lowlevel interfact, with different want_ext_default and want_default values. It is only a failure, if the application changed both, conn->want and conn->want_ext. This function was failing in issue #1171, because high level fuse_fs_init() was changing values and then lowlevel do_init() was incorrectly failing on that. This also adds a new test (test_want_conversion) and sets values into example/{hello.c,hello_ll.c} Also some more internal users of conn->want are converted to fuse_{set,unset}_feature_flag(). Closes: https://github.com/libfuse/libfuse/issues/1171 Signed-off-by: Bernd Schubert <bernd@bsbernd.com> (cherry picked from commit f68970cd235a7e14026ca0f6240428bbebe8223b)
2025-02-18Avoid nested function declarations in helper functionsBernd Schubert-4/+0
libfuse-3.17 introduced several functions that should only be called via inlined helper functions, never directly. To enforce this, these functions were declared within the inlined functions. However, this triggers the compiler warning "-Werror=nested-externs". While this warning is valid, the nested declarations were intentional to prevent direct usage of these functions. Rather than suppressing the warning with pragmas, move these function declarations outside the helper functions while maintaining the intended access restrictions through other means. Closes: https://github.com/libfuse/libfuse/issues/1134 Signed-off-by: Bernd Schubert <bschubert@ddn.com>
2025-02-10fuse_new version fixes: Change to fuse_new_versionedBernd Schubert-2/+2
Another additon for https://github.com/libfuse/libfuse/issues/1092 Use _fuse_new_versioned() instead of _fuse_new_317 and actually also remove symbol versioning for it - we don't need it. Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
2025-02-10Rename fuse_main_real_317 to fuse_main_real_versionedBernd Schubert-6/+8
As suggested by Bill in Issue #1092, rename to _versioned so that applications using dlopen/dlvsym better understand the meaning of this function. Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
2025-02-10Make fuse_main_real() not symboledBernd Schubert-4/+4
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>
2025-02-10Avoid global declarion of internal functions that are new in 3.17Bernd Schubert-0/+4
_fuse_new() is not supposed to be called by external users outside of internal functions or static inlined functions. This also removes several functions from lib/fuse_versionscript which where added and exported by commit 58f85bfa9b7d ("Add in the libfuse version a program...) as these are libfuse internal only. Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
2024-05-13Add in the libfuse version a program was compiled with (#942)Bernd Schubert-4/+16
The API stays the same, the libfuse version comes from inlined functions, which are defined fuse_lowlevel.h and fuse.h. As these inlined functions are defined in the header files they get added into the application, similar as if these were preprocessor macros. Macro vs inlined function is then just a style issue - I personally prefer the latter. fuse_session_new() -> static inlinei, in the application _fuse_session_new -> inside of libfuse fuse_new() -> static inline, in the application _fuse_new() -> inside of libfuse Note: Entirely untested is the fuse 30 api - we need a test for it. And we do not have any ABI tests at all. Signed-off-by: Bernd Schubert <bernd.schubert@fastmail.fm>
2023-03-11Fix max_threads command line parameter propagationSarath Lakshman-0/+1
The fuse_main_real() method doesn't apply the max_threads parameter parsed through the commandline arguments. This commit fixes the wiring of max_threads argument.
2023-02-20Avoid max-idle threads warningBernd Schubert-2/+1
If a program with API before 312 did not set max_idle_threads the new default from fuse_parse_cmdline_312() is applied, which sets UINT_MAX (-1). Later in compat fuse_session_loop_mt_32 the old config v1 struct is converted and that conversion prints a warning if the default unset value was used. This could have also happened to programs using the current API, which just apply values struct fuse_cmdline_opts, without checking if the defaults are set.
2023-01-28Install a the configure_file (config.h) and use in headersBernd Schubert-1/+1
This addresses: https://github.com/libfuse/libfuse/issues/724 HAVE_LIBC_VERSIONED_SYMBOLS configures the library if to use versioned symbols and is set at meson configuration time. External filesystems (the main target, actually) include fuse headers and the preprocessor then acts on HAVE_LIBC_VERSIONED_SYMBOLS. Problem was now that 'config.h' was not distributed with libfuse and so HAVE_LIBC_VERSIONED_SYMBOLS was never defined with external tools and the preprocessor did the wrong decision. This commit also increases the the minimal meson version, as this depends on meson feature only available in 0.50 <quote 'meson' > WARNING: Project specifies a minimum meson_ version '>= 0.42' but uses features which were added in newer versions: * 0.50.0: {'install arg in configure_file'} </quote> Additionally the config file has been renamed to "fuse_config.h" to avoid clashes - 'config.h' is not very specific.
2023-01-04Fix ublic/apple build for the fuse_parse_cmdline ABI symbolBernd Schubert-12/+0
For __APPLE__ and __ULIBC__, which are assumed to not support versioned symbols, helper.c has a compat ABI symbol for fuse_parse_cmdline(). However that ABI symbol was conflicting with the API macro (which redirects to the right API function for recompilations against current libfuse). Additionally the parameter 'opts' had a typo and was called 'out_opts'.
2022-09-11Fix the fuse_parse_cmdline@FUSE_3.0 ABI compat symbolBernd Schubert-1/+1
There was a simple typo and sym1 didn't match the function name with the older __asm__(".symver " sym1 "," sym2) way to define ABI compatibility. Witht the newer "__attribute__ ((symver (sym2)))" sym1 is not used at all and in manual testing the issue didn't come up therefore.
2022-09-04fuse-loop/fuse_do_work: Avoid lots of thread creations/destructionsBernd Schubert-3/+44
On benchmarking metadata operations with a single threaded bonnie++ and "max_idle_threads" limited to 1, 'top' was showing suspicious 160% cpu usage. Profiling the system with flame graphs showed that an astonishing amount of CPU time was spent in thread creation and destruction. After verifying the code it turned out that fuse_do_work() was creating a new thread every time all existing idle threads were already busy. And then just a few lines later after processing the current request it noticed that it had created too many threads and destructed the current thread. I.e. there was a thread creation/destruction ping-pong. Code is changed to only create new threads if the max number of threads is not reached. Furthermore, thread destruction is disabled, as creation/destruction is expensive in general. With this change cpu usage of passthrough_hp went from ~160% to ~80% (with different values of max_idle_threads). And bonnie values got approximately faster by 90%. This is a with single threaded bonnie++ bonnie++ -x 4 -q -s0 -d <path> -n 30:1:1:10 -r 0 Without this patch, using the default max_idle_threads=10 and just a single bonnie++ the thread creation/destruction code path is not triggered. Just one libfuse and one application thread is just a corner case - the requirement for the issue was just n-application-threads >= max_idle_threads. Signed-off-by: Bernd Schubert <bschubert@ddn.com>
2022-09-04API update for fuse_loop_config additionsBernd Schubert-5/+13
struct fuse_loop_config was passed as a plain struct, without any version identifer. This had two implications 1) Any addition of new parameters required a FUSE_SYMVER for fuse_session_loop_mt() and fuse_loop_mt() as otherwise a read beyond end-of previous struct size might have happened. 2) Filesystems also might have been recompiled and the developer might not have noticed the struct extensions and unexpected for the developer (or people recomliling the code) uninitialized parameters would have been passed. Code is updated to have struct fuse_loop_config as an opaque/private data type for file systems that want version 312 (FUSE_MAKE_VERSION(3, 12)). The deprecated fuse_loop_config_v1 is visible, but should not be used outside of internal conversion functions File systems that want version >= 32 < 312 get the previous struct (through ifdefs) and the #define of fuse_loop_mt and fuse_session_loop_mt ensures that these recompiled file systems call into the previous API, which then converts the struct. This is similar to existing compiled applications when just libfuse updated, but binaries it is solved with the FUSE_SYMVER ABI compact declarations. Signed-off-by: Bernd Schubert <bschubert@ddn.com>
2019-09-04Introduce callback for loggingStefan Hajnoczi-5/+5
Introduce an API for custom log handler functions. This allows libfuse applications to send messages to syslog(3) or other logging systems. See include/fuse_log.h for details. Convert libfuse from fprintf(stderr, ...) to log_fuse(level, ...). Most messages are error messages with FUSE_LOG_ERR log level. There are also some debug messages which now use the FUSE_LOG_DEBUG log level. Note that lib/mount_util.c is used by both libfuse and fusermount3. Since fusermount3 does not link against libfuse, we cannot call fuse_log() from lib/mount_util.c. This file will continue to use fprintf(stderr, ...) until someone figures out how to split it up. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2018-10-09Add unprivileged option in `mount.fuse3`Mattias Nissler-0/+18
The unprivileged option allows to run the FUSE file system process without privileges by dropping capabilities and preventing them from being re-acquired via setuid / fscaps etc. To accomplish this, mount.fuse sets up the `/dev/fuse` file descriptor and mount itself and passes the file descriptor via the `/dev/fd/%u` mountpoint syntax to the FUSE file system.
2018-10-09Allow passing `/dev/fuse` file descriptor from parent processMattias Nissler-1/+6
This adds support for a mode of operation in which a privileged parent process opens `/dev/fuse` and takes care of mounting. The FUSE file system daemon can then run as an unprivileged child that merely processes requests on the FUSE file descriptor, which get passed using the special `/dev/fd/%u` syntax for the mountpoint parameter. The main benefit is that no privileged operations need to be performed by the FUSE file system daemon itself directly or indirectly, so the FUSE process can run with fully unprivileged and mechanisms like securebits and no_new_privs can be used to prevent subprocesses from re-acquiring privilege via setuid, fscaps, etc. This reduces risk in case the FUSE file system gets exploited by malicious file system data. Below is an example that illustrates this. Note that I'm using shell for presentation purposes, the expectation is that the parent process will implement the equivalent of the `mount -i` and `capsh` commands. ``` \# example/hello can mount successfully with privilege $ sudo sh -c "LD_LIBRARY_PATH=build/lib ./example/hello /mnt/tmp" $ sudo cat /mnt/tmp/hello Hello World! $ sudo umount /mnt/tmp \# example/hello fails to mount without privilege $ sudo capsh --drop=all --secbits=0x2f -- -c 'LD_LIBRARY_PATH=build/lib ./example/hello -f /mnt/tmp' fusermount3: mount failed: Operation not permitted \# Passing FUSE file descriptor via /dev/fd/%u allows example/hello to work without privilege $ sudo sh -c ' exec 17<>/dev/fuse mount -i -o nodev,nosuid,noexec,fd=17,rootmode=40000,user_id=0,group_id=0 -t fuse hello /mnt/tmp capsh --drop=all --secbits=0x2f -- -c "LD_LIBRARY_PATH=build/lib example/hello /dev/fd/17" ' $ sudo cat /mnt/tmp/hello Hello World! $ sudo umount /mnt/tmp ```
2018-08-29return different non-zero error codes (#290)Oded Arbel-6/+6
Return different error codes from fuse_main()
2017-11-27Spelling (#223)Josh Soref-1/+1
Fix spelling errors
2017-09-19Don't use external symbol names in internal filesNikolaus Rath-1/+1
The fuse_session_loop_mt() and fuse_loop_mt() symbols are only visible when linking against the shared object. The code in lib/, however, is compiled *into* the shared object and should thus use the internal names of these functions. Surprisingly enough, the code still worked before - but only when link time optimization was disabled. Unfortunately, we still can't compile with LTO because it seems that enabling LTO somehow makes the tagged symbols vanish. Without lto, we have: $ nm lib/libfuse3.so | grep fuse_new 0000000000011070 T fuse_new_30 0000000000010a00 t fuse_new_31 0000000000011070 T fuse_new@FUSE_3.0 0000000000010a00 T fuse_new@@FUSE_3.1 and with LTO: $ nm lib/libfuse3.so | grep fuse_new 0000000000019a70 T fuse_new_30 0000000000019270 t fuse_new_31 See also issue #198.
2017-08-24Add idle_threads mount option.Joseph Dodge-3/+13
2017-08-22Fix two compiler warnings.Nikolaus Rath-1/+1
2017-08-14directly call fuse_new_31() instead of fuse_new() internallyuserwithuid-1/+1
this fixes building with lto, which failed since commit 503e32d01e4db00e90d7acfd81ab05386559069f
2017-08-03Simplify and fix FreeBSD fsname handlingNikolaus Rath-29/+10
This should simplify the code a lot. It also corrects a bug in that the (former) add_default_fsname() function actually set the -osubtype option.
2017-08-03FreeBSD: supprt fsname= optionBaptiste Daroussin-0/+30
2017-07-08Added public fuse_lib_help(), bumped minor versionNikolaus Rath-8/+4
2016-10-20Accept zero value for fuse_conn_info optionsNikolaus Rath-5/+15
This may not make sense for all options, but it's good practice.
2016-10-18Cast to void where we deliberately ignore return valuesNikolaus Rath-2/+2
2016-10-18Ignore some errorsMihail Konev-2/+2
2016-10-16Inlined fuse_mount_help() into fuse_lowlevel_help().Nikolaus Rath-1/+0
Both the BSD and Linux implementation actually accept mostly the same FUSE-specific mount options. Up to now, the BSD help function appended the output of ``mount_fusefs --help``, but looking at http://www.unix.com/man-page/freebsd/8/mount_fusefs/ this is likely more confusing than helpful (since the user is not actually invoking mount_fusefs directly, most of the options don't make sense).
2016-10-15Make --help output more suitable for end-userNikolaus Rath-3/+3
We now only list options that are potentially useful for an end-user (and unlikely to accidentally break a file system). The full list of FUSE options has been moved to the documentation of the fuse_new() and fuse_session_new() functions.
2016-10-15Unify handling of fuse_conn_info optionsNikolaus Rath-0/+127
Instead of using command line options to modify struct fuse_conn_info before and after calling the init() handler, we now give the file system explicit control over this.
2016-10-13Make -o clone_fd into a parameter of session_loop_mt().Nikolaus Rath-1/+3
This option really affects the behavior of the session loop, not the low-level interface. Therefore, it does not belong in the fuse_session object.
2016-10-10fuse_main(): extend support for printing helpNikolaus Rath-0/+3
There's now a way to inhibit the "usage" line (which actually got lost in commit 225c12aebf2d), which makes it easier for simply file-systems to generate good-looking --help output.
2016-10-09fuse_main_real(): use fuse_parse_cmdline().Nikolaus Rath-11/+1
2016-10-09fuse_parse_cmdline(): do not print help/version textNikolaus Rath-35/+3
The current behavior makes it difficult to add help for additional options. With the change, this becomes a lot easier.
2016-10-04Clarified purpose of helper.c, moved *version() to fuse.cNikolaus Rath-10/+4
2016-10-02Don't handle --help and --version in fuse_session_new().Nikolaus Rath-119/+114
Help and version messages can be generated using the new fuse_lowlevel_help(), fuse_lowlevel_version(), fuse_mount_help(), and fuse_mount_version() functions. The fuse_parse_cmdline() function has been made more powerful to do this automatically, and is now explicitly intended only for low-level API users. This is a code simplication patch. We don't have to parse for --help and --version in quite as many places, and we no longer have a low-level initialization function be responsible for the (super-high level) task of printing a program usage message. In the high-level API, we can now handle the command line parsing earlier and avoid running other initialization code if we're just going to abort later on.
2016-10-02Add section headings for --help outputNikolaus Rath-6/+3
Also, do not include "General options" in usage message.
2016-10-02Turn struct fuse_chan into an implementation detailNikolaus Rath-23/+21
The only struct fuse_chan that's accessible to the user application is the "master" channel that is returned by fuse_mount and stored in struct fuse_session. When using the multi-threaded main loop with the "clone_fd" option, each worker thread gets its own struct fuse_chan. However, none of these are available to the user application, nor do they hold references to struct fuse_session (the pointer is always null). Therefore, any presence of struct fuse_chan can be removed without loss of functionality by relying on struct fuse_session instead. This reduces the number of API functions and removes a potential source of confusion (since the new API no longer looks as if it might be possible to add multiple channels to one session, or to share one channel between multiple sessions). Fixes issue #17.
2016-10-02Introduce separate mount/umount functions for low-level API.Nikolaus Rath-35/+0
2016-10-01Improve documentation of argument parsing.Nikolaus Rath-0/+1
2016-06-20libfuse/fuse_daemonize: wait until daemon child process is ready (#55)Hendrik Brueckner-0/+14
Mounting a FUSE file system remotely using SSH in combination with pseudo-terminal allocation (-t), results in "Transport endpoint is not connected" errors when trying to access the file system contents. For example: # ssh -t root@localhost "cmsfs-fuse /dev/disk/by-path/ccw-0.0.0190 /CMSFS" Connection to localhost closed. # ls /CMSFS ls: cannot access '/CMSFS': Transport endpoint is not connected The cmsfs-fuse main program (which can also be any other FUSE file system) calls into the fuse_main() libfuse library function. The fuse_main() function later calls fuse_daemonize() to fork the daemon process to handle the FUSE file system I/O. The fuse_daemonize() function calls fork() as usual. The child proceeds with setsid() and then redirecting its file descriptors to /dev/null etc. The parent process, simply exits. The child's functions and the parent's exit creates a subtle race. This is seen with an SSH connection. The SSH command above calls cmsfs-fuse on an allocated pseudo-terminal device (-t option). If the parent exits, SSH receives the command completion and closes the connection, that means, it closes the master side of the pseudo-terminal. This causes a HUP signal being sent to the process group on the pseudo-terminal. At this point in time, the child might not have completed the setsid() call and, hence, becomes terminated. Note that fuse daemon sets up its signal handlers after fuse_daemonize() has completed. Even if the child has the chance to disassociate from its parent process group to become it's own process group with setsid(), the child still has the pseudo-terminal opened as stdin, stdout, and stderr. So the pseudo-terminal still behave as controlling terminal and might cause a SIGHUP at closing the the master side. To solve the problem, the parent has to wait until the child (the fuse daemon process) has completed its processing, that means, has become its own process group with setsid() and closed any file descriptors pointing to the pseudo-terminal. Closes: #27 Reported-by: Ofer Baruch <oferba@il.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
2015-09-29Merge branch 'clone_fd'Miklos Szeredi-2/+1
2015-08-12Canonicalised whitespace and added ChangeLog entryChristopher Harrison-1/+1
2015-07-30Added fuse_pkgversion functionChristopher Harrison-0/+4
Returns the full PACKAGE_VERSION string, per autoconf
2015-05-18libfuse: refcount fuse_chan objectsMiklos Szeredi-2/+1
New functions: fuse_chan_get(), fuse_chan_put(). Removed function: fuse_chan_destroy().
2013-07-26Print help on stdout instead of stderrMiklos Szeredi-16/+12
2013-06-21libfuse: remove session and chan abstractionsMiklos Szeredi-1/+1
There's actually just one type of channel and session, so we don't need the generic callback functions.