freebsd-dev/sys/dev/filemon/filemon.c
2012-10-26 20:24:13 +00:00

304 lines
7.3 KiB
C

/*-
* Copyright (c) 2011, David E. O'Brien.
* Copyright (c) 2009-2011, Juniper Networks, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JUNIPER NETWORKS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL JUNIPER NETWORKS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/file.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/condvar.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/ioccom.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/syscall.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/uio.h>
#if __FreeBSD_version >= 900041
#include <sys/capability.h>
#endif
#include "filemon.h"
#if defined(COMPAT_IA32) || defined(COMPAT_FREEBSD32) || defined(COMPAT_ARCH32)
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_proto.h>
extern struct sysentvec ia32_freebsd_sysvec;
#endif
extern struct sysentvec elf32_freebsd_sysvec;
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,
.d_close = filemon_close,
.d_ioctl = filemon_ioctl,
.d_open = filemon_open,
.d_name = "filemon",
};
MALLOC_DECLARE(M_FILEMON);
MALLOC_DEFINE(M_FILEMON, "filemon", "File access monitor");
struct filemon {
TAILQ_ENTRY(filemon) link; /* Link into the in-use list. */
struct mtx mtx; /* Lock mutex for this filemon. */
struct cv cv; /* Lock condition variable for this
filemon. */
struct file *fp; /* Output file pointer. */
struct thread *locker; /* Ptr to the thread locking this
filemon. */
pid_t pid; /* The process ID being monitored. */
char fname1[MAXPATHLEN]; /* Temporary filename buffer. */
char fname2[MAXPATHLEN]; /* Temporary filename buffer. */
char msgbufr[1024]; /* Output message buffer. */
};
static TAILQ_HEAD(, filemon) filemons_inuse = TAILQ_HEAD_INITIALIZER(filemons_inuse);
static TAILQ_HEAD(, filemon) filemons_free = TAILQ_HEAD_INITIALIZER(filemons_free);
static int n_readers = 0;
static struct mtx access_mtx;
static struct cv access_cv;
static struct thread *access_owner = NULL;
static struct thread *access_requester = NULL;
static struct cdev *filemon_dev;
#include "filemon_lock.c"
#include "filemon_wrapper.c"
static void
filemon_dtr(void *data)
{
struct filemon *filemon = data;
if (filemon != NULL) {
struct file *fp = filemon->fp;
/* Get exclusive write access. */
filemon_lock_write();
/* Remove from the in-use list. */
TAILQ_REMOVE(&filemons_inuse, filemon, link);
filemon->fp = NULL;
filemon->pid = -1;
/* Add to the free list. */
TAILQ_INSERT_TAIL(&filemons_free, filemon, link);
/* Give up write access. */
filemon_unlock_write();
if (fp != NULL)
fdrop(fp, curthread);
}
}
#if __FreeBSD_version < 900041
#define FGET_WRITE(a1, a2, a3) fget_write((a1), (a2), (a3))
#else
#define FGET_WRITE(a1, a2, a3) fget_write((a1), (a2), CAP_WRITE | CAP_SEEK, (a3))
#endif
static int
filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused,
struct thread *td)
{
int error = 0;
struct filemon *filemon;
devfs_get_cdevpriv((void **) &filemon);
switch (cmd) {
/* Set the output file descriptor. */
case FILEMON_SET_FD:
if ((error = FGET_WRITE(td, *(int *)data, &filemon->fp)) == 0)
/* Write the file header. */
filemon_comment(filemon);
break;
/* Set the monitored process ID. */
case FILEMON_SET_PID:
filemon->pid = *((pid_t *)data);
break;
default:
error = EINVAL;
break;
}
return (error);
}
static int
filemon_open(struct cdev *dev, int oflags __unused, int devtype __unused,
struct thread *td __unused)
{
struct filemon *filemon;
/* Get exclusive write access. */
filemon_lock_write();
if ((filemon = TAILQ_FIRST(&filemons_free)) != NULL)
TAILQ_REMOVE(&filemons_free, filemon, link);
/* Give up write access. */
filemon_unlock_write();
if (filemon == NULL) {
filemon = malloc(sizeof(struct filemon), M_FILEMON,
M_WAITOK | M_ZERO);
filemon->fp = NULL;
mtx_init(&filemon->mtx, "filemon", "filemon", MTX_DEF);
cv_init(&filemon->cv, "filemon");
}
filemon->pid = curproc->p_pid;
devfs_set_cdevpriv(filemon, filemon_dtr);
/* Get exclusive write access. */
filemon_lock_write();
/* Add to the in-use list. */
TAILQ_INSERT_TAIL(&filemons_inuse, filemon, link);
/* Give up write access. */
filemon_unlock_write();
return (0);
}
static int
filemon_close(struct cdev *dev __unused, int flag __unused, int fmt __unused,
struct thread *td __unused)
{
return (0);
}
static void
filemon_load(void *dummy __unused)
{
mtx_init(&access_mtx, "filemon", "filemon", MTX_DEF);
cv_init(&access_cv, "filemon");
/* Install the syscall wrappers. */
filemon_wrapper_install();
filemon_dev = make_dev(&filemon_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666,
"filemon");
}
static int
filemon_unload(void)
{
struct filemon *filemon;
int error = 0;
/* Get exclusive write access. */
filemon_lock_write();
if (TAILQ_FIRST(&filemons_inuse) != NULL)
error = EBUSY;
else {
destroy_dev(filemon_dev);
/* Deinstall the syscall wrappers. */
filemon_wrapper_deinstall();
}
/* Give up write access. */
filemon_unlock_write();
if (error == 0) {
/* free() filemon structs free list. */
filemon_lock_write();
while ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) {
TAILQ_REMOVE(&filemons_free, filemon, link);
mtx_destroy(&filemon->mtx);
cv_destroy(&filemon->cv);
free(filemon, M_FILEMON);
}
filemon_unlock_write();
mtx_destroy(&access_mtx);
cv_destroy(&access_cv);
}
return (error);
}
static int
filemon_modevent(module_t mod __unused, int type, void *data)
{
int error = 0;
switch (type) {
case MOD_LOAD:
filemon_load(data);
break;
case MOD_UNLOAD:
error = filemon_unload();
break;
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
DEV_MODULE(filemon, filemon_modevent, NULL);
MODULE_VERSION(filemon, 1);