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 #include <sys/mplock2.h> 64 65 /* 66 * The routines implemented in this file are described in: 67 * Leffler, et al.: The Design and Implementation of the 4.3BSD 68 * UNIX Operating System (Addison Welley, 1989) 69 * on pages 62-63. 70 * 71 * Arguably, to simplify accounting operations, this mechanism should 72 * be replaced by one in which an accounting log file (similar to /dev/klog) 73 * is read by a user process, etc. However, that has its own problems. 74 */ 75 76 /* 77 * Internal accounting functions. 78 * The former's operation is described in Leffler, et al., and the latter 79 * was provided by UCB with the 4.4BSD-Lite release 80 */ 81 static comp_t encode_comp_t (u_long, u_long); 82 static void acctwatch (void *); 83 84 /* 85 * Accounting callout handle used for periodic scheduling of 86 * acctwatch. 87 */ 88 static struct callout acctwatch_handle; 89 90 /* 91 * Accounting vnode pointer, and saved vnode pointer. 92 */ 93 static struct vnode *acctp; 94 static struct vnode *savacctp; 95 96 /* 97 * Values associated with enabling and disabling accounting 98 */ 99 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 100 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 101 &acctsuspend, 0, "Percentage of free disk space below which accounting will be suspended"); 102 103 static int acctresume = 4; /* resume when free space risen to > 4% */ 104 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 105 &acctresume, 0, "Minimum percentage of free disk space needed to resume accounting"); 106 107 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 108 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 109 &acctchkfreq, 0, "Frequency (in seconds) of free disk space checking"); 110 111 static void 112 acct_init(void *arg __unused) 113 { 114 callout_init(&acctwatch_handle); 115 } 116 SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL); 117 118 /* 119 * Accounting system call. Written based on the specification and 120 * previous implementation done by Mark Tinguely. 121 * 122 * acct(char *path) 123 * 124 * MPALMOSTSAFE 125 */ 126 int 127 sys_acct(struct acct_args *uap) 128 { 129 struct thread *td = curthread; 130 struct nlookupdata nd; 131 struct vnode *vp; 132 int error; 133 134 error = priv_check(td, PRIV_ACCT); 135 if (error) 136 return (error); 137 138 get_mplock(); 139 140 /* 141 * If accounting is to be started to a file, open that file for 142 * appending and make sure it's a 'normal'. 143 */ 144 if (uap->path != NULL) { 145 error = nlookup_init(&nd, uap->path, UIO_USERSPACE, 146 NLC_LOCKVP); 147 if (error == 0) 148 error = vn_open(&nd, NULL, FWRITE | O_APPEND, 0); 149 if (error == 0 && nd.nl_open_vp->v_type != VREG) 150 error = EACCES; 151 if (error) { 152 nlookup_done(&nd); 153 goto done; 154 } 155 vp = nd.nl_open_vp; 156 nd.nl_open_vp = NULL; 157 nlookup_done(&nd); 158 159 vn_unlock(vp); 160 } else { 161 vp = NULL; 162 } 163 164 /* 165 * If accounting was previously enabled, kill the old space-watcher, 166 * close the file. 167 */ 168 if (acctp != NULLVP || savacctp != NULLVP) { 169 callout_stop(&acctwatch_handle); 170 error = vn_close((acctp != NULLVP ? acctp : savacctp), 171 FWRITE | O_APPEND); 172 acctp = savacctp = NULLVP; 173 } 174 175 /* 176 * If no new file opened then leave. We never did an nlookup so 177 * don't try cleaning it up. 178 */ 179 if (uap->path == NULL) 180 goto done; 181 182 /* 183 * Save the new accounting file vnode, and schedule the new 184 * free space watcher. 185 */ 186 acctp = vp; 187 acctwatch(NULL); 188 done: 189 rel_mplock(); 190 return (error); 191 } 192 193 /* 194 * Write out process accounting information, on process exit. 195 * Data to be written out is specified in Leffler, et al. 196 * and are enumerated below. (They're also noted in the system 197 * "acct.h" header file.) 198 */ 199 200 int 201 acct_process(struct proc *p) 202 { 203 struct acct acct; 204 struct rusage *r; 205 struct rusage ru; 206 struct timeval tmp; 207 struct rlimit rlim; 208 int t; 209 struct vnode *vp; 210 211 /* If accounting isn't enabled, don't bother */ 212 vp = acctp; 213 if (vp == NULLVP) 214 return (0); 215 216 /* 217 * Get process accounting information. 218 */ 219 220 /* (1) The name of the command that ran */ 221 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 222 223 /* (2) The amount of user and system time that was used */ 224 calcru_proc(p, &ru); 225 acct.ac_utime = encode_comp_t(ru.ru_utime.tv_sec, ru.ru_utime.tv_usec); 226 acct.ac_stime = encode_comp_t(ru.ru_stime.tv_sec, ru.ru_stime.tv_usec); 227 228 /* (3) The elapsed time the commmand ran (and its starting time) */ 229 acct.ac_btime = p->p_start.tv_sec; 230 microtime(&tmp); 231 timevalsub(&tmp, &p->p_start); 232 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 233 234 /* (4) The average amount of memory used */ 235 r = &p->p_ru; 236 tmp = ru.ru_utime;; 237 timevaladd(&tmp, &ru.ru_stime); 238 t = tmp.tv_sec * hz + tmp.tv_usec / ustick; 239 if (t) 240 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 241 else 242 acct.ac_mem = 0; 243 244 /* (5) The number of disk I/O operations done */ 245 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 246 247 /* (6) The UID and GID of the process */ 248 acct.ac_uid = p->p_ucred->cr_ruid; 249 acct.ac_gid = p->p_ucred->cr_rgid; 250 251 /* (7) The terminal from which the process was started */ 252 if ((p->p_flags & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 253 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 254 else 255 acct.ac_tty = NOUDEV; 256 257 /* (8) The boolean flags that tell how the process terminated, etc. */ 258 acct.ac_flag = p->p_acflag; 259 260 /* 261 * Eliminate any file size rlimit. 262 */ 263 rlim.rlim_cur = RLIM_INFINITY; 264 rlim.rlim_max = RLIM_INFINITY; 265 plimit_modify(p, RLIMIT_FSIZE, &rlim); 266 267 /* 268 * Write the accounting information to the file. 269 */ 270 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 271 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, 272 NULL)); 273 } 274 275 /* 276 * Encode_comp_t converts from ticks in seconds and microseconds 277 * to ticks in 1/AHZ seconds. The encoding is described in 278 * Leffler, et al., on page 63. 279 */ 280 281 #define MANTSIZE 13 /* 13 bit mantissa. */ 282 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 283 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 284 285 static comp_t 286 encode_comp_t(u_long s, u_long us) 287 { 288 int exp, rnd; 289 290 exp = 0; 291 rnd = 0; 292 s *= AHZ; 293 s += us / (1000000 / AHZ); /* Maximize precision. */ 294 295 while (s > MAXFRACT) { 296 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 297 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 298 exp++; 299 } 300 301 /* If we need to round up, do it (and handle overflow correctly). */ 302 if (rnd && (++s > MAXFRACT)) { 303 s >>= EXPSIZE; 304 exp++; 305 } 306 307 /* Clean it up and polish it off. */ 308 exp <<= MANTSIZE; /* Shift the exponent into place */ 309 exp += s; /* and add on the mantissa. */ 310 return (exp); 311 } 312 313 /* 314 * Periodically check the file system to see if accounting 315 * should be turned on or off. Beware the case where the vnode 316 * has been vgone()'d out from underneath us, e.g. when the file 317 * system containing the accounting file has been forcibly unmounted. 318 */ 319 /* ARGSUSED */ 320 static void 321 acctwatch(void *a) 322 { 323 struct statfs sb; 324 325 if (savacctp != NULLVP) { 326 if (savacctp->v_type == VBAD) { 327 (void) vn_close(savacctp, FWRITE | O_APPEND); 328 savacctp = NULLVP; 329 return; 330 } 331 (void)VFS_STATFS(savacctp->v_mount, &sb, proc0.p_ucred); 332 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 333 acctp = savacctp; 334 savacctp = NULLVP; 335 log(LOG_NOTICE, "Accounting resumed\n"); 336 } 337 } else { 338 if (acctp == NULLVP) 339 return; 340 if (acctp->v_type == VBAD) { 341 (void) vn_close(acctp, FWRITE | O_APPEND); 342 acctp = NULLVP; 343 return; 344 } 345 (void)VFS_STATFS(acctp->v_mount, &sb, proc0.p_ucred); 346 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 347 savacctp = acctp; 348 acctp = NULLVP; 349 log(LOG_NOTICE, "Accounting suspended\n"); 350 } 351 } 352 callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL); 353 } 354