1 /*- 2 * Copyright (c) 2011, David E. O'Brien. 3 * Copyright (c) 2009-2011, Juniper Networks, Inc. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY JUNIPER NETWORKS AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL JUNIPER NETWORKS OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/file.h> 33 #include <sys/systm.h> 34 #include <sys/buf.h> 35 #include <sys/condvar.h> 36 #include <sys/conf.h> 37 #include <sys/fcntl.h> 38 #include <sys/ioccom.h> 39 #include <sys/kernel.h> 40 #include <sys/malloc.h> 41 #include <sys/module.h> 42 #include <sys/mutex.h> 43 #include <sys/poll.h> 44 #include <sys/proc.h> 45 #include <sys/queue.h> 46 #include <sys/syscall.h> 47 #include <sys/sysent.h> 48 #include <sys/sysproto.h> 49 #include <sys/uio.h> 50 51 #if __FreeBSD_version >= 900041 52 #include <sys/capability.h> 53 #endif 54 55 #include "filemon.h" 56 57 #if defined(COMPAT_IA32) || defined(COMPAT_FREEBSD32) || defined(COMPAT_ARCH32) 58 #include <compat/freebsd32/freebsd32_syscall.h> 59 #include <compat/freebsd32/freebsd32_proto.h> 60 61 extern struct sysentvec ia32_freebsd_sysvec; 62 #endif 63 64 extern struct sysentvec elf32_freebsd_sysvec; 65 extern struct sysentvec elf64_freebsd_sysvec; 66 67 static d_close_t filemon_close; 68 static d_ioctl_t filemon_ioctl; 69 static d_open_t filemon_open; 70 static int filemon_unload(void); 71 static void filemon_load(void *); 72 73 static struct cdevsw filemon_cdevsw = { 74 .d_version = D_VERSION, 75 .d_close = filemon_close, 76 .d_ioctl = filemon_ioctl, 77 .d_open = filemon_open, 78 .d_name = "filemon", 79 }; 80 81 MALLOC_DECLARE(M_FILEMON); 82 MALLOC_DEFINE(M_FILEMON, "filemon", "File access monitor"); 83 84 struct filemon { 85 TAILQ_ENTRY(filemon) link; /* Link into the in-use list. */ 86 struct mtx mtx; /* Lock mutex for this filemon. */ 87 struct cv cv; /* Lock condition variable for this 88 filemon. */ 89 struct file *fp; /* Output file pointer. */ 90 struct thread *locker; /* Ptr to the thread locking this 91 filemon. */ 92 pid_t pid; /* The process ID being monitored. */ 93 char fname1[MAXPATHLEN]; /* Temporary filename buffer. */ 94 char fname2[MAXPATHLEN]; /* Temporary filename buffer. */ 95 char msgbufr[1024]; /* Output message buffer. */ 96 }; 97 98 static TAILQ_HEAD(, filemon) filemons_inuse = TAILQ_HEAD_INITIALIZER(filemons_inuse); 99 static TAILQ_HEAD(, filemon) filemons_free = TAILQ_HEAD_INITIALIZER(filemons_free); 100 static int n_readers = 0; 101 static struct mtx access_mtx; 102 static struct cv access_cv; 103 static struct thread *access_owner = NULL; 104 static struct thread *access_requester = NULL; 105 106 static struct cdev *filemon_dev; 107 108 #include "filemon_lock.c" 109 #include "filemon_wrapper.c" 110 111 static void 112 filemon_dtr(void *data) 113 { 114 struct filemon *filemon = data; 115 116 if (filemon != NULL) { 117 struct file *fp = filemon->fp; 118 119 /* Get exclusive write access. */ 120 filemon_lock_write(); 121 122 /* Remove from the in-use list. */ 123 TAILQ_REMOVE(&filemons_inuse, filemon, link); 124 125 filemon->fp = NULL; 126 filemon->pid = -1; 127 128 /* Add to the free list. */ 129 TAILQ_INSERT_TAIL(&filemons_free, filemon, link); 130 131 /* Give up write access. */ 132 filemon_unlock_write(); 133 134 if (fp != NULL) 135 fdrop(fp, curthread); 136 } 137 } 138 139 #if __FreeBSD_version < 900041 140 #define FGET_WRITE(a1, a2, a3) fget_write((a1), (a2), (a3)) 141 #else 142 #define FGET_WRITE(a1, a2, a3) fget_write((a1), (a2), CAP_WRITE | CAP_SEEK, (a3)) 143 #endif 144 145 static int 146 filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused, 147 struct thread *td) 148 { 149 int error = 0; 150 struct filemon *filemon; 151 152 devfs_get_cdevpriv((void **) &filemon); 153 154 switch (cmd) { 155 /* Set the output file descriptor. */ 156 case FILEMON_SET_FD: 157 if ((error = FGET_WRITE(td, *(int *)data, &filemon->fp)) == 0) 158 /* Write the file header. */ 159 filemon_comment(filemon); 160 break; 161 162 /* Set the monitored process ID. */ 163 case FILEMON_SET_PID: 164 filemon->pid = *((pid_t *)data); 165 break; 166 167 default: 168 error = EINVAL; 169 break; 170 } 171 172 return (error); 173 } 174 175 static int 176 filemon_open(struct cdev *dev, int oflags __unused, int devtype __unused, 177 struct thread *td __unused) 178 { 179 struct filemon *filemon; 180 181 /* Get exclusive write access. */ 182 filemon_lock_write(); 183 184 if ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) 185 TAILQ_REMOVE(&filemons_free, filemon, link); 186 187 /* Give up write access. */ 188 filemon_unlock_write(); 189 190 if (filemon == NULL) { 191 filemon = malloc(sizeof(struct filemon), M_FILEMON, 192 M_WAITOK | M_ZERO); 193 194 filemon->fp = NULL; 195 196 mtx_init(&filemon->mtx, "filemon", "filemon", MTX_DEF); 197 cv_init(&filemon->cv, "filemon"); 198 } 199 200 filemon->pid = curproc->p_pid; 201 202 devfs_set_cdevpriv(filemon, filemon_dtr); 203 204 /* Get exclusive write access. */ 205 filemon_lock_write(); 206 207 /* Add to the in-use list. */ 208 TAILQ_INSERT_TAIL(&filemons_inuse, filemon, link); 209 210 /* Give up write access. */ 211 filemon_unlock_write(); 212 213 return (0); 214 } 215 216 static int 217 filemon_close(struct cdev *dev __unused, int flag __unused, int fmt __unused, 218 struct thread *td __unused) 219 { 220 221 return (0); 222 } 223 224 static void 225 filemon_load(void *dummy __unused) 226 { 227 mtx_init(&access_mtx, "filemon", "filemon", MTX_DEF); 228 cv_init(&access_cv, "filemon"); 229 230 /* Install the syscall wrappers. */ 231 filemon_wrapper_install(); 232 233 filemon_dev = make_dev(&filemon_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, 234 "filemon"); 235 } 236 237 static int 238 filemon_unload(void) 239 { 240 struct filemon *filemon; 241 int error = 0; 242 243 /* Get exclusive write access. */ 244 filemon_lock_write(); 245 246 if (TAILQ_FIRST(&filemons_inuse) != NULL) 247 error = EBUSY; 248 else { 249 destroy_dev(filemon_dev); 250 251 /* Deinstall the syscall wrappers. */ 252 filemon_wrapper_deinstall(); 253 } 254 255 /* Give up write access. */ 256 filemon_unlock_write(); 257 258 if (error == 0) { 259 /* free() filemon structs free list. */ 260 filemon_lock_write(); 261 while ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) { 262 TAILQ_REMOVE(&filemons_free, filemon, link); 263 mtx_destroy(&filemon->mtx); 264 cv_destroy(&filemon->cv); 265 free(filemon, M_FILEMON); 266 } 267 filemon_unlock_write(); 268 269 mtx_destroy(&access_mtx); 270 cv_destroy(&access_cv); 271 } 272 273 return (error); 274 } 275 276 static int 277 filemon_modevent(module_t mod __unused, int type, void *data) 278 { 279 int error = 0; 280 281 switch (type) { 282 case MOD_LOAD: 283 filemon_load(data); 284 break; 285 286 case MOD_UNLOAD: 287 error = filemon_unload(); 288 break; 289 290 case MOD_SHUTDOWN: 291 break; 292 293 default: 294 error = EOPNOTSUPP; 295 break; 296 297 } 298 299 return (error); 300 } 301 302 DEV_MODULE(filemon, filemon_modevent, NULL); 303 MODULE_VERSION(filemon, 1); 304