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 "opt_compat.h" 32 33 #include <sys/param.h> 34 #include <sys/file.h> 35 #include <sys/systm.h> 36 #include <sys/buf.h> 37 #include <sys/condvar.h> 38 #include <sys/conf.h> 39 #include <sys/fcntl.h> 40 #include <sys/ioccom.h> 41 #include <sys/kernel.h> 42 #include <sys/malloc.h> 43 #include <sys/module.h> 44 #include <sys/mutex.h> 45 #include <sys/poll.h> 46 #include <sys/proc.h> 47 #include <sys/queue.h> 48 #include <sys/syscall.h> 49 #include <sys/sysent.h> 50 #include <sys/sysproto.h> 51 #include <sys/uio.h> 52 53 #if __FreeBSD_version >= 900041 54 #include <sys/capsicum.h> 55 #endif 56 57 #include "filemon.h" 58 59 #if defined(COMPAT_IA32) || defined(COMPAT_FREEBSD32) || defined(COMPAT_ARCH32) 60 #include <compat/freebsd32/freebsd32_syscall.h> 61 #include <compat/freebsd32/freebsd32_proto.h> 62 63 extern struct sysentvec ia32_freebsd_sysvec; 64 #endif 65 66 extern struct sysentvec elf32_freebsd_sysvec; 67 extern struct sysentvec elf64_freebsd_sysvec; 68 69 static d_close_t filemon_close; 70 static d_ioctl_t filemon_ioctl; 71 static d_open_t filemon_open; 72 static int filemon_unload(void); 73 static void filemon_load(void *); 74 75 static struct cdevsw filemon_cdevsw = { 76 .d_version = D_VERSION, 77 .d_close = filemon_close, 78 .d_ioctl = filemon_ioctl, 79 .d_open = filemon_open, 80 .d_name = "filemon", 81 }; 82 83 MALLOC_DECLARE(M_FILEMON); 84 MALLOC_DEFINE(M_FILEMON, "filemon", "File access monitor"); 85 86 struct filemon { 87 TAILQ_ENTRY(filemon) link; /* Link into the in-use list. */ 88 struct mtx mtx; /* Lock mutex for this filemon. */ 89 struct cv cv; /* Lock condition variable for this 90 filemon. */ 91 struct file *fp; /* Output file pointer. */ 92 struct thread *locker; /* Ptr to the thread locking this 93 filemon. */ 94 pid_t pid; /* The process ID being monitored. */ 95 char fname1[MAXPATHLEN]; /* Temporary filename buffer. */ 96 char fname2[MAXPATHLEN]; /* Temporary filename buffer. */ 97 char msgbufr[1024]; /* Output message buffer. */ 98 }; 99 100 static TAILQ_HEAD(, filemon) filemons_inuse = TAILQ_HEAD_INITIALIZER(filemons_inuse); 101 static TAILQ_HEAD(, filemon) filemons_free = TAILQ_HEAD_INITIALIZER(filemons_free); 102 static int n_readers = 0; 103 static struct mtx access_mtx; 104 static struct cv access_cv; 105 static struct thread *access_owner = NULL; 106 static struct thread *access_requester = NULL; 107 108 static struct cdev *filemon_dev; 109 110 #include "filemon_lock.c" 111 #include "filemon_wrapper.c" 112 113 static void 114 filemon_dtr(void *data) 115 { 116 struct filemon *filemon = data; 117 118 if (filemon != NULL) { 119 struct file *fp = filemon->fp; 120 121 /* Get exclusive write access. */ 122 filemon_lock_write(); 123 124 /* Remove from the in-use list. */ 125 TAILQ_REMOVE(&filemons_inuse, filemon, link); 126 127 filemon->fp = NULL; 128 filemon->pid = -1; 129 130 /* Add to the free list. */ 131 TAILQ_INSERT_TAIL(&filemons_free, filemon, link); 132 133 /* Give up write access. */ 134 filemon_unlock_write(); 135 136 if (fp != NULL) 137 fdrop(fp, curthread); 138 } 139 } 140 141 static int 142 filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused, 143 struct thread *td) 144 { 145 int error = 0; 146 struct filemon *filemon; 147 struct proc *p; 148 #if __FreeBSD_version >= 900041 149 cap_rights_t rights; 150 #endif 151 152 devfs_get_cdevpriv((void **) &filemon); 153 154 switch (cmd) { 155 /* Set the output file descriptor. */ 156 case FILEMON_SET_FD: 157 error = fget_write(td, *(int *)data, 158 #if __FreeBSD_version >= 900041 159 cap_rights_init(&rights, CAP_PWRITE), 160 #endif 161 &filemon->fp); 162 if (error == 0) 163 /* Write the file header. */ 164 filemon_comment(filemon); 165 break; 166 167 /* Set the monitored process ID. */ 168 case FILEMON_SET_PID: 169 error = pget(*((pid_t *)data), PGET_CANDEBUG | PGET_NOTWEXIT, 170 &p); 171 if (error == 0) { 172 filemon->pid = p->p_pid; 173 PROC_UNLOCK(p); 174 } 175 break; 176 177 default: 178 error = EINVAL; 179 break; 180 } 181 182 return (error); 183 } 184 185 static int 186 filemon_open(struct cdev *dev, int oflags __unused, int devtype __unused, 187 struct thread *td __unused) 188 { 189 struct filemon *filemon; 190 191 /* Get exclusive write access. */ 192 filemon_lock_write(); 193 194 if ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) 195 TAILQ_REMOVE(&filemons_free, filemon, link); 196 197 /* Give up write access. */ 198 filemon_unlock_write(); 199 200 if (filemon == NULL) { 201 filemon = malloc(sizeof(struct filemon), M_FILEMON, 202 M_WAITOK | M_ZERO); 203 204 filemon->fp = NULL; 205 206 mtx_init(&filemon->mtx, "filemon", "filemon", MTX_DEF); 207 cv_init(&filemon->cv, "filemon"); 208 } 209 210 filemon->pid = curproc->p_pid; 211 212 devfs_set_cdevpriv(filemon, filemon_dtr); 213 214 /* Get exclusive write access. */ 215 filemon_lock_write(); 216 217 /* Add to the in-use list. */ 218 TAILQ_INSERT_TAIL(&filemons_inuse, filemon, link); 219 220 /* Give up write access. */ 221 filemon_unlock_write(); 222 223 return (0); 224 } 225 226 static int 227 filemon_close(struct cdev *dev __unused, int flag __unused, int fmt __unused, 228 struct thread *td __unused) 229 { 230 231 return (0); 232 } 233 234 static void 235 filemon_load(void *dummy __unused) 236 { 237 mtx_init(&access_mtx, "filemon", "filemon", MTX_DEF); 238 cv_init(&access_cv, "filemon"); 239 240 /* Install the syscall wrappers. */ 241 filemon_wrapper_install(); 242 243 filemon_dev = make_dev(&filemon_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, 244 "filemon"); 245 } 246 247 static int 248 filemon_unload(void) 249 { 250 struct filemon *filemon; 251 int error = 0; 252 253 /* Get exclusive write access. */ 254 filemon_lock_write(); 255 256 if (TAILQ_FIRST(&filemons_inuse) != NULL) 257 error = EBUSY; 258 else { 259 destroy_dev(filemon_dev); 260 261 /* Deinstall the syscall wrappers. */ 262 filemon_wrapper_deinstall(); 263 } 264 265 /* Give up write access. */ 266 filemon_unlock_write(); 267 268 if (error == 0) { 269 /* free() filemon structs free list. */ 270 filemon_lock_write(); 271 while ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) { 272 TAILQ_REMOVE(&filemons_free, filemon, link); 273 mtx_destroy(&filemon->mtx); 274 cv_destroy(&filemon->cv); 275 free(filemon, M_FILEMON); 276 } 277 filemon_unlock_write(); 278 279 mtx_destroy(&access_mtx); 280 cv_destroy(&access_cv); 281 } 282 283 return (error); 284 } 285 286 static int 287 filemon_modevent(module_t mod __unused, int type, void *data) 288 { 289 int error = 0; 290 291 switch (type) { 292 case MOD_LOAD: 293 filemon_load(data); 294 break; 295 296 case MOD_UNLOAD: 297 error = filemon_unload(); 298 break; 299 300 case MOD_SHUTDOWN: 301 break; 302 303 default: 304 error = EOPNOTSUPP; 305 break; 306 307 } 308 309 return (error); 310 } 311 312 DEV_MODULE(filemon, filemon_modevent, NULL); 313 MODULE_VERSION(filemon, 1); 314