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MFC r296286,r296470,r296472,r296473,r296575:

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r296286:
    Remove filemon->lock wrappers.
  r296470:
    Only call bwillwrite() for logging to vnodes, as other fo_write() calls do.
  r296472:
    Require kldunload -f to unload.
  r296473:
    Add missing break for r296472.
  r296575:
    FILEMON_SET_FD: Disallow changing the fd.
This commit is contained in:
bdrewery 2016-03-12 19:07:21 +00:00
parent c677bff3bc
commit bb2a228f2d
4 changed files with 49 additions and 51 deletions
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18
share/man/man4/filemon.4
View File

@ -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 .

24
sys/dev/filemon/filemon.c
View File

@ -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;

14
sys/dev/filemon/filemon_lock.c
View File

@ -28,20 +28,6 @@
#include <sys/cdefs.h>
__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)
{

44
sys/dev/filemon/filemon_wrapper.c
View File

@ -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);
}
}