diff --git a/share/man/man4/filemon.4 b/share/man/man4/filemon.4 index fe0c43049b2f..92876a32d48f 100644 --- a/share/man/man4/filemon.4 +++ b/share/man/man4/filemon.4 @@ -31,7 +31,7 @@ .\" .\" $FreeBSD$ .\" -.Dd January 28, 2016 +.Dd March 9, 2016 .Dt FILEMON 4 .Os .Sh NAME @@ -125,6 +125,19 @@ function returns the value 0 if successful; otherwise the value \-1 is returned and the global variable .Va errno is set to indicate the error. +.Sh ERRORS +The +.Fn ioctl +system call +with +.Dv FILEMON_SET_FD +will fail if: +.Bl -tag -width Er +.It Bq Er EEXIST +The +.Nm +handle is already associated with a file descriptor. +.El .Sh FILES .Bl -tag -width ".Pa /dev/filemon" .It Pa /dev/filemon @@ -193,3 +206,6 @@ Only children of the set process are logged. Processes can escape being traced by double forking. This is not seen as a problem as the intended use is build monitoring, which does not make sense to have daemons for. +.Pp +Unloading the module may panic the system, thus requires using +.Ic kldunload -f . diff --git a/sys/dev/filemon/filemon.c b/sys/dev/filemon/filemon.c index 352f68241ede..e33536ff2e5a 100644 --- a/sys/dev/filemon/filemon.c +++ b/sys/dev/filemon/filemon.c @@ -71,8 +71,6 @@ extern struct sysentvec elf64_freebsd_sysvec; static d_close_t filemon_close; static d_ioctl_t filemon_ioctl; static d_open_t filemon_open; -static int filemon_unload(void); -static void filemon_load(void *); static struct cdevsw filemon_cdevsw = { .d_version = D_VERSION, @@ -130,7 +128,7 @@ filemon_dtr(void *data) /* Follow same locking order as filemon_pid_check. */ filemon_lock_write(); - filemon_filemon_lock(filemon); + sx_xlock(&filemon->lock); /* Remove from the in-use list. */ TAILQ_REMOVE(&filemons_inuse, filemon, link); @@ -143,7 +141,7 @@ filemon_dtr(void *data) TAILQ_INSERT_TAIL(&filemons_free, filemon, link); /* Give up write access. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); filemon_unlock_write(); if (fp != NULL) @@ -165,13 +163,15 @@ filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused, if ((error = devfs_get_cdevpriv((void **) &filemon)) != 0) return (error); - filemon_filemon_lock(filemon); + sx_xlock(&filemon->lock); switch (cmd) { /* Set the output file descriptor. */ case FILEMON_SET_FD: - if (filemon->fp != NULL) - fdrop(filemon->fp, td); + if (filemon->fp != NULL) { + error = EEXIST; + break; + } error = fget_write(td, *(int *)data, #if __FreeBSD_version >= 900041 @@ -198,7 +198,7 @@ filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused, break; } - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); return (error); } @@ -308,6 +308,14 @@ filemon_modevent(module_t mod __unused, int type, void *data) error = filemon_unload(); break; + case MOD_QUIESCE: + /* + * The wrapper implementation is unsafe for reliable unload. + * Require forcing an unload. + */ + error = EBUSY; + break; + case MOD_SHUTDOWN: break; diff --git a/sys/dev/filemon/filemon_lock.c b/sys/dev/filemon/filemon_lock.c index a0347000fc23..5cac47c7386e 100644 --- a/sys/dev/filemon/filemon_lock.c +++ b/sys/dev/filemon/filemon_lock.c @@ -28,20 +28,6 @@ #include __FBSDID("$FreeBSD$"); -static __inline void -filemon_filemon_lock(struct filemon *filemon) -{ - - sx_xlock(&filemon->lock); -} - -static __inline void -filemon_filemon_unlock(struct filemon *filemon) -{ - - sx_xunlock(&filemon->lock); -} - static __inline void filemon_lock_read(void) { diff --git a/sys/dev/filemon/filemon_wrapper.c b/sys/dev/filemon/filemon_wrapper.c index 40e09e3a3f6a..28d34a98bf7b 100644 --- a/sys/dev/filemon/filemon_wrapper.c +++ b/sys/dev/filemon/filemon_wrapper.c @@ -80,7 +80,8 @@ filemon_output(struct filemon *filemon, char *msg, size_t len) auio.uio_td = curthread; auio.uio_offset = (off_t) -1; - bwillwrite(); + if (filemon->fp->f_type == DTYPE_VNODE) + bwillwrite(); fo_write(filemon->fp, &auio, curthread->td_ucred, 0, curthread); } @@ -100,7 +101,7 @@ filemon_pid_check(struct proc *p) TAILQ_FOREACH(filemon, &filemons_inuse, link) { if (p == filemon->p) { sx_sunlock(&proctree_lock); - filemon_filemon_lock(filemon); + sx_xlock(&filemon->lock); filemon_unlock_read(); return (filemon); } @@ -131,8 +132,7 @@ filemon_wrapper_chdir(struct thread *td, struct chdir_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -160,8 +160,7 @@ filemon_event_process_exec(void *arg __unused, struct proc *p, filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); free(freepath, M_TEMP); } @@ -199,8 +198,7 @@ filemon_wrapper_open(struct thread *td, struct open_args *uap) curproc->p_pid, filemon->fname1); filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -252,8 +250,7 @@ filemon_wrapper_openat(struct thread *td, struct openat_args *uap) curproc->p_pid, filemon->fname2, filemon->fname1); filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -281,8 +278,7 @@ filemon_wrapper_rename(struct thread *td, struct rename_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -310,8 +306,7 @@ filemon_wrapper_link(struct thread *td, struct link_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -339,8 +334,7 @@ filemon_wrapper_symlink(struct thread *td, struct symlink_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -369,8 +363,7 @@ filemon_wrapper_linkat(struct thread *td, struct linkat_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -397,8 +390,7 @@ filemon_wrapper_stat(struct thread *td, struct stat_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -426,8 +418,7 @@ filemon_wrapper_freebsd32_stat(struct thread *td, filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -462,8 +453,7 @@ filemon_event_process_exit(void *arg __unused, struct proc *p) filemon->p = NULL; } - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -486,8 +476,7 @@ filemon_wrapper_unlink(struct thread *td, struct unlink_args *uap) filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } } @@ -508,8 +497,7 @@ filemon_event_process_fork(void *arg __unused, struct proc *p1, filemon_output(filemon, filemon->msgbufr, len); - /* Unlock the found filemon structure. */ - filemon_filemon_unlock(filemon); + sx_xunlock(&filemon->lock); } }