libfuse/fuse_daemonize: wait until daemon child process is ready (#55)
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.
Dalvik Khertel [Thu, 9 Aug 2012 12:48:20 +0000 (12:48 +0000)]
libfuse: pass security context options to kernel
Mount can be used with an "-o context=" option in order to specify a
mountpoint-wide SELinux security context different from the default context
provided by the active SELinux policy.
This is useful in order to enable users to mount multiple sshfs targets under
distinct contexts, which is my main motivation for getting this patch mainlined.
Nikolaus Rath [Thu, 14 Jan 2016 19:15:00 +0000 (11:15 -0800)]
Changed Changelog format
Up to now, the Changelog has essentially been a (manually maintained)
copy of the git commit history. This doesn't seem to have any point
other than following the GNU coding standards. I believe it's much
better to use the Changelog to summarize the release-to-release
changes that are most important for users, so this is what we'll do
from now on.
Nikolaus Rath [Thu, 14 Jan 2016 18:14:35 +0000 (10:14 -0800)]
Update makeconf.sh
Describe why manual copying of config.rpath is necessary, and fail
with a more helpful message if it can't be found.
Remove code for systems without autoreconf - it's apparently not used
by anyone since it has been broken for quite some time (there is no
`kernel` directory anymore).
Miklos Szeredi [Thu, 20 Jun 2013 09:43:02 +0000 (11:43 +0200)]
libfuse: fix multiple close of device fd
- fuse_kern_unmount closes handle (e.g. 19)
- a thread in my process opens a file - the OS assigns newly freed
handle (i.e. 19)
- fuse_kern_chan_destroy closes the same handle (i.e. 19)
- a thread in my process opens another file - the OS assigns newly
freed handle (i.e. 19)
- * MAYHEM *
Miklos Szeredi [Mon, 4 Feb 2013 17:30:14 +0000 (18:30 +0100)]
libfuse: configure: detect new util-linux
Apparently new versions of util-linux umount return with an exit status of 1
even if the "--fake" option is recognised (despite being documented otherwise).
Check this condition and don't complain about util-linux version.
Miklos Szeredi [Fri, 24 Aug 2012 13:13:17 +0000 (15:13 +0200)]
Fix missing config.h in buffer.c
Due to an oversight, splice will never actually be used for i/o. Someone forgot
to #include "config.h" in lib/buffer.c (in fact almost no files include that
header). As a result, even though configure detects splice support and puts
HAVE_SPLICE in config.h, buffer.c is always compiled as if there is no splice
support.
Also add #include "config.h" to fuse.c and fuse_lowlevel.c. These currently
include it indirectly through fuse_misc.h, but we don't want to depend on that.
Miklos Szeredi [Tue, 14 Aug 2012 09:18:07 +0000 (11:18 +0200)]
Fix "fuse internal error: node NNN not found"
Commit 4dc7e675bb (Don't unhash name in FORGET) broke the forget logic in a
subtle way, resulting in "fuse internal error: node NNN not found" and causing
the filesystem daemon to abort.
Fix by incrementing the node refcount if nlookup goes from zero to one.
The failure path of try_get_path2() erronously tried to free the "path1" value
(an address on the stack) instead of the allocated string pointed to by "path1".
This caused the library to crash.
fallocate filesystem operation preallocates media space for the given file.
If fallocate returns success then any subsequent write to the given range
never fails with 'not enough space' error.
Miklos Szeredi [Wed, 16 May 2012 14:45:27 +0000 (16:45 +0200)]
Fix -pthread in fuse.pc
Linking to a library that uses threads requires the application to be linked
with -pthreads otherwise some pthread functions will be linked to stubs in
glibc. So move -pthread from Libs.private to Libs in fuse.pc.
Miklos Szeredi [Fri, 9 Dec 2011 15:07:55 +0000 (16:07 +0100)]
Fix hang in wait_on_path()
Ville Silventoinen reported that fs_racer in LTP triggered a hang in
wait_on_path(). This bug was caused by try_get_path() not resetting "ticket" on
permanent failure.
fusexmp uses utimens and takes that function for granted. It is part of
POSIX exended API set 2 and some systems do not have it yet. Attached
patch checks for utimens availability and returns ENOSYS if unavailable.
John Muir [Tue, 6 Dec 2011 20:56:34 +0000 (21:56 +0100)]
libfuse: Notifying the kernel of deletion.
libfuse part to allow a FUSE file-system to tell the kernel when a
file or directory is deleted. If the specified dentry has the
specified inode number, the kernel will unhash it.
Signed-off-by: John Muir <john@jmuir.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Miklos Szeredi [Thu, 17 Nov 2011 11:36:38 +0000 (12:36 +0100)]
Fix the following compile error
fusermount.c: In function 'clone_newns':
fusermount.c:315:2: warning: implicit declaration of function 'clone' [-Wimplicit-function-declaration]
fusermount.c:315:44: error: 'CLONE_NEWNS' undeclared (first use in this function)
fusermount.c:315:44: note: each undeclared identifier is reported only once for each function it appears in
fusermount.c:317:1: warning: control reaches end of non-void function [-Wreturn-type]
Miklos Szeredi [Sun, 23 Oct 2011 08:07:20 +0000 (10:07 +0200)]
Reply with ENOMEM in case of failure to allocate request
Reply to request with ENOMEM in case of failure to allocate request
structure. Otherwise the task issuing the request will just freeze up
until the filesystem daemon is killed. Reported by Stephan Kulow
Add ->flock() operation to low and high level interfaces
This fixes problems with emulating flock() with POSIX locking.
Reported by Sebastian Pipping.
As with lock/setlk/getlk most filesystems don't need to implement
this, as the kernel takes care of file locking. The only reason to
implement locking operations is for network filesystems which want
file locking to work between clients.