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/capability.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 #if __FreeBSD_version < 900041 142 #define FGET_WRITE(a1, a2, a3) fget_write((a1), (a2), (a3)) 143 #else 144 #define FGET_WRITE(a1, a2, a3) fget_write((a1), (a2), CAP_WRITE | CAP_SEEK, (a3)) 145 #endif 146 147 static int 148 filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused, 149 struct thread *td) 150 { 151 int error = 0; 152 struct filemon *filemon; 153 struct proc *p; 154 155 devfs_get_cdevpriv((void **) &filemon); 156 157 switch (cmd) { 158 /* Set the output file descriptor. */ 159 case FILEMON_SET_FD: 160 if ((error = FGET_WRITE(td, *(int *)data, &filemon->fp)) == 0) 161 /* Write the file header. */ 162 filemon_comment(filemon); 163 break; 164 165 /* Set the monitored process ID. */ 166 case FILEMON_SET_PID: 167 error = pget(*((pid_t *)data), PGET_CANDEBUG | PGET_NOTWEXIT, 168 &p); 169 if (error == 0) { 170 filemon->pid = p->p_pid; 171 PROC_UNLOCK(p); 172 } 173 break; 174 175 default: 176 error = EINVAL; 177 break; 178 } 179 180 return (error); 181 } 182 183 static int 184 filemon_open(struct cdev *dev, int oflags __unused, int devtype __unused, 185 struct thread *td __unused) 186 { 187 struct filemon *filemon; 188 189 /* Get exclusive write access. */ 190 filemon_lock_write(); 191 192 if ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) 193 TAILQ_REMOVE(&filemons_free, filemon, link); 194 195 /* Give up write access. */ 196 filemon_unlock_write(); 197 198 if (filemon == NULL) { 199 filemon = malloc(sizeof(struct filemon), M_FILEMON, 200 M_WAITOK | M_ZERO); 201 202 filemon->fp = NULL; 203 204 mtx_init(&filemon->mtx, "filemon", "filemon", MTX_DEF); 205 cv_init(&filemon->cv, "filemon"); 206 } 207 208 filemon->pid = curproc->p_pid; 209 210 devfs_set_cdevpriv(filemon, filemon_dtr); 211 212 /* Get exclusive write access. */ 213 filemon_lock_write(); 214 215 /* Add to the in-use list. */ 216 TAILQ_INSERT_TAIL(&filemons_inuse, filemon, link); 217 218 /* Give up write access. */ 219 filemon_unlock_write(); 220 221 return (0); 222 } 223 224 static int 225 filemon_close(struct cdev *dev __unused, int flag __unused, int fmt __unused, 226 struct thread *td __unused) 227 { 228 229 return (0); 230 } 231 232 static void 233 filemon_load(void *dummy __unused) 234 { 235 mtx_init(&access_mtx, "filemon", "filemon", MTX_DEF); 236 cv_init(&access_cv, "filemon"); 237 238 /* Install the syscall wrappers. */ 239 filemon_wrapper_install(); 240 241 filemon_dev = make_dev(&filemon_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, 242 "filemon"); 243 } 244 245 static int 246 filemon_unload(void) 247 { 248 struct filemon *filemon; 249 int error = 0; 250 251 /* Get exclusive write access. */ 252 filemon_lock_write(); 253 254 if (TAILQ_FIRST(&filemons_inuse) != NULL) 255 error = EBUSY; 256 else { 257 destroy_dev(filemon_dev); 258 259 /* Deinstall the syscall wrappers. */ 260 filemon_wrapper_deinstall(); 261 } 262 263 /* Give up write access. */ 264 filemon_unlock_write(); 265 266 if (error == 0) { 267 /* free() filemon structs free list. */ 268 filemon_lock_write(); 269 while ((filemon = TAILQ_FIRST(&filemons_free)) != NULL) { 270 TAILQ_REMOVE(&filemons_free, filemon, link); 271 mtx_destroy(&filemon->mtx); 272 cv_destroy(&filemon->cv); 273 free(filemon, M_FILEMON); 274 } 275 filemon_unlock_write(); 276 277 mtx_destroy(&access_mtx); 278 cv_destroy(&access_cv); 279 } 280 281 return (error); 282 } 283 284 static int 285 filemon_modevent(module_t mod __unused, int type, void *data) 286 { 287 int error = 0; 288 289 switch (type) { 290 case MOD_LOAD: 291 filemon_load(data); 292 break; 293 294 case MOD_UNLOAD: 295 error = filemon_unload(); 296 break; 297 298 case MOD_SHUTDOWN: 299 break; 300 301 default: 302 error = EOPNOTSUPP; 303 break; 304 305 } 306 307 return (error); 308 } 309 310 DEV_MODULE(filemon, filemon_modevent, NULL); 311 MODULE_VERSION(filemon, 1); 312