1 /*- 2 * Copyright (c) 1994 Christopher G. Demetriou 3 * Copyright (c) 1982, 1986, 1989, 1993 4 * The Regents of the University of California. All rights reserved. 5 * (c) UNIX System Laboratories, Inc. 6 * All or some portions of this file are derived from material licensed 7 * to the University of California by American Telephone and Telegraph 8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 9 * the permission of UNIX System Laboratories, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 40 * $FreeBSD: src/sys/kern/kern_acct.c,v 1.23.2.1 2002/07/24 18:33:55 johan Exp $ 41 * $DragonFly: src/sys/kern/kern_acct.c,v 1.28 2008/05/08 01:26:00 dillon Exp $ 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/sysproto.h> 47 #include <sys/proc.h> 48 #include <sys/priv.h> 49 #include <sys/mount.h> 50 #include <sys/vnode.h> 51 #include <sys/fcntl.h> 52 #include <sys/syslog.h> 53 #include <sys/kernel.h> 54 #include <sys/sysent.h> 55 #include <sys/sysctl.h> 56 #include <sys/nlookup.h> 57 #include <sys/acct.h> 58 #include <sys/resourcevar.h> 59 #include <sys/tty.h> 60 61 #include <vm/vm_zone.h> 62 63 /* 64 * The routines implemented in this file are described in: 65 * Leffler, et al.: The Design and Implementation of the 4.3BSD 66 * UNIX Operating System (Addison Welley, 1989) 67 * on pages 62-63. 68 * 69 * Arguably, to simplify accounting operations, this mechanism should 70 * be replaced by one in which an accounting log file (similar to /dev/klog) 71 * is read by a user process, etc. However, that has its own problems. 72 */ 73 74 /* 75 * Internal accounting functions. 76 * The former's operation is described in Leffler, et al., and the latter 77 * was provided by UCB with the 4.4BSD-Lite release 78 */ 79 static comp_t encode_comp_t (u_long, u_long); 80 static void acctwatch (void *); 81 82 /* 83 * Accounting callout handle used for periodic scheduling of 84 * acctwatch. 85 */ 86 static struct callout acctwatch_handle; 87 88 /* 89 * Accounting vnode pointer, and saved vnode pointer. 90 */ 91 static struct vnode *acctp; 92 static struct vnode *savacctp; 93 94 /* 95 * Values associated with enabling and disabling accounting 96 */ 97 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 98 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 99 &acctsuspend, 0, "Percentage of free disk space below which accounting will be suspended"); 100 101 static int acctresume = 4; /* resume when free space risen to > 4% */ 102 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 103 &acctresume, 0, "Minimum percentage of free disk space needed to resume accounting"); 104 105 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 106 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 107 &acctchkfreq, 0, "Frequency (in seconds) of free disk space checking"); 108 109 static void 110 acct_init(void *arg __unused) 111 { 112 callout_init(&acctwatch_handle); 113 } 114 SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL); 115 116 /* 117 * Accounting system call. Written based on the specification and 118 * previous implementation done by Mark Tinguely. 119 * 120 * acct(char *path) 121 * 122 * MPALMOSTSAFE 123 */ 124 int 125 sys_acct(struct acct_args *uap) 126 { 127 struct thread *td = curthread; 128 struct nlookupdata nd; 129 struct vnode *vp; 130 int error; 131 132 error = priv_check(td, PRIV_ACCT); 133 if (error) 134 return (error); 135 136 get_mplock(); 137 138 /* 139 * If accounting is to be started to a file, open that file for 140 * appending and make sure it's a 'normal'. 141 */ 142 if (uap->path != NULL) { 143 error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 144 NLC_LOCKVP); 145 if (error == 0) 146 error = vn_open(&nd, NULL, FWRITE | O_APPEND, 0); 147 if (error == 0 && nd.nl_open_vp->v_type != VREG) 148 error = EACCES; 149 if (error) { 150 nlookup_done(&nd); 151 goto done; 152 } 153 vp = nd.nl_open_vp; 154 nd.nl_open_vp = NULL; 155 nlookup_done(&nd); 156 157 vn_unlock(vp); 158 } else { 159 vp = NULL; 160 } 161 162 /* 163 * If accounting was previously enabled, kill the old space-watcher, 164 * close the file. 165 */ 166 if (acctp != NULLVP || savacctp != NULLVP) { 167 callout_stop(&acctwatch_handle); 168 error = vn_close((acctp != NULLVP ? acctp : savacctp), 169 FWRITE | O_APPEND); 170 acctp = savacctp = NULLVP; 171 } 172 173 /* 174 * If no new file opened then leave. We never did an nlookup so 175 * don't try cleaning it up. 176 */ 177 if (uap->path == NULL) 178 goto done; 179 180 /* 181 * Save the new accounting file vnode, and schedule the new 182 * free space watcher. 183 */ 184 acctp = vp; 185 acctwatch(NULL); 186 done: 187 rel_mplock(); 188 return (error); 189 } 190 191 /* 192 * Write out process accounting information, on process exit. 193 * Data to be written out is specified in Leffler, et al. 194 * and are enumerated below. (They're also noted in the system 195 * "acct.h" header file.) 196 */ 197 198 int 199 acct_process(struct proc *p) 200 { 201 struct acct acct; 202 struct rusage *r; 203 struct rusage ru; 204 struct timeval tmp; 205 struct rlimit rlim; 206 int t; 207 struct vnode *vp; 208 209 /* If accounting isn't enabled, don't bother */ 210 vp = acctp; 211 if (vp == NULLVP) 212 return (0); 213 214 /* 215 * Get process accounting information. 216 */ 217 218 /* (1) The name of the command that ran */ 219 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 220 221 /* (2) The amount of user and system time that was used */ 222 calcru_proc(p, &ru); 223 acct.ac_utime = encode_comp_t(ru.ru_utime.tv_sec, ru.ru_utime.tv_usec); 224 acct.ac_stime = encode_comp_t(ru.ru_stime.tv_sec, ru.ru_stime.tv_usec); 225 226 /* (3) The elapsed time the commmand ran (and its starting time) */ 227 acct.ac_btime = p->p_start.tv_sec; 228 microtime(&tmp); 229 timevalsub(&tmp, &p->p_start); 230 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 231 232 /* (4) The average amount of memory used */ 233 r = &p->p_ru; 234 tmp = ru.ru_utime;; 235 timevaladd(&tmp, &ru.ru_stime); 236 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 237 if (t) 238 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 239 else 240 acct.ac_mem = 0; 241 242 /* (5) The number of disk I/O operations done */ 243 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 244 245 /* (6) The UID and GID of the process */ 246 acct.ac_uid = p->p_ucred->cr_ruid; 247 acct.ac_gid = p->p_ucred->cr_rgid; 248 249 /* (7) The terminal from which the process was started */ 250 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 251 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 252 else 253 acct.ac_tty = NOUDEV; 254 255 /* (8) The boolean flags that tell how the process terminated, etc. */ 256 acct.ac_flag = p->p_acflag; 257 258 /* 259 * Eliminate any file size rlimit. 260 */ 261 rlim.rlim_cur = RLIM_INFINITY; 262 rlim.rlim_max = RLIM_INFINITY; 263 plimit_modify(p, RLIMIT_FSIZE, &rlim); 264 265 /* 266 * Write the accounting information to the file. 267 */ 268 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 269 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 270 NULL)); 271 } 272 273 /* 274 * Encode_comp_t converts from ticks in seconds and microseconds 275 * to ticks in 1/AHZ seconds. The encoding is described in 276 * Leffler, et al., on page 63. 277 */ 278 279 #define MANTSIZE 13 /* 13 bit mantissa. */ 280 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 281 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 282 283 static comp_t 284 encode_comp_t(u_long s, u_long us) 285 { 286 int exp, rnd; 287 288 exp = 0; 289 rnd = 0; 290 s *= AHZ; 291 s += us / (1000000 / AHZ); /* Maximize precision. */ 292 293 while (s > MAXFRACT) { 294 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 295 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 296 exp++; 297 } 298 299 /* If we need to round up, do it (and handle overflow correctly). */ 300 if (rnd && (++s > MAXFRACT)) { 301 s >>= EXPSIZE; 302 exp++; 303 } 304 305 /* Clean it up and polish it off. */ 306 exp <<= MANTSIZE; /* Shift the exponent into place */ 307 exp += s; /* and add on the mantissa. */ 308 return (exp); 309 } 310 311 /* 312 * Periodically check the file system to see if accounting 313 * should be turned on or off. Beware the case where the vnode 314 * has been vgone()'d out from underneath us, e.g. when the file 315 * system containing the accounting file has been forcibly unmounted. 316 */ 317 /* ARGSUSED */ 318 static void 319 acctwatch(void *a) 320 { 321 struct statfs sb; 322 323 if (savacctp != NULLVP) { 324 if (savacctp->v_type == VBAD) { 325 (void) vn_close(savacctp, FWRITE | O_APPEND); 326 savacctp = NULLVP; 327 return; 328 } 329 (void)VFS_STATFS(savacctp->v_mount, &sb, proc0.p_ucred); 330 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 331 acctp = savacctp; 332 savacctp = NULLVP; 333 log(LOG_NOTICE, "Accounting resumed\n"); 334 } 335 } else { 336 if (acctp == NULLVP) 337 return; 338 if (acctp->v_type == VBAD) { 339 (void) vn_close(acctp, FWRITE | O_APPEND); 340 acctp = NULLVP; 341 return; 342 } 343 (void)VFS_STATFS(acctp->v_mount, &sb, proc0.p_ucred); 344 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 345 savacctp = acctp; 346 acctp = NULLVP; 347 log(LOG_NOTICE, "Accounting suspended\n"); 348 } 349 } 350 callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL); 351 } 352