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 * $FreeBSD$ 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/lock.h> 46 #include <sys/mutex.h> 47 #include <sys/sysproto.h> 48 #include <sys/proc.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/namei.h> 57 #include <sys/acct.h> 58 #include <sys/resourcevar.h> 59 #include <sys/tty.h> 60 61 /* 62 * The routines implemented in this file are described in: 63 * Leffler, et al.: The Design and Implementation of the 4.3BSD 64 * UNIX Operating System (Addison Welley, 1989) 65 * on pages 62-63. 66 * 67 * Arguably, to simplify accounting operations, this mechanism should 68 * be replaced by one in which an accounting log file (similar to /dev/klog) 69 * is read by a user process, etc. However, that has its own problems. 70 */ 71 72 /* 73 * Internal accounting functions. 74 * The former's operation is described in Leffler, et al., and the latter 75 * was provided by UCB with the 4.4BSD-Lite release 76 */ 77 static comp_t encode_comp_t(u_long, u_long); 78 static void acctwatch(void *); 79 80 /* 81 * Accounting callout used for periodic scheduling of acctwatch. 82 */ 83 static struct callout acctwatch_callout; 84 85 /* 86 * Accounting vnode pointer, saved vnode pointer, and flags for each. 87 */ 88 static struct vnode *acctp; 89 static int acctflags; 90 static struct vnode *savacctp; 91 static int savacctflags; 92 93 /* 94 * Values associated with enabling and disabling accounting 95 */ 96 static int acctsuspend = 2; /* stop accounting when < 2% free space left */ 97 SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW, 98 &acctsuspend, 0, "percentage of free disk space below which accounting stops"); 99 100 static int acctresume = 4; /* resume when free space risen to > 4% */ 101 SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW, 102 &acctresume, 0, "percentage of free disk space above which accounting resumes"); 103 104 static int acctchkfreq = 15; /* frequency (in seconds) to check space */ 105 SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW, 106 &acctchkfreq, 0, "frequency for checking the free space"); 107 108 /* 109 * Accounting system call. Written based on the specification and 110 * previous implementation done by Mark Tinguely. 111 * 112 * MPSAFE 113 */ 114 int 115 acct(td, uap) 116 struct thread *td; 117 struct acct_args /* { 118 syscallarg(char *) path; 119 } */ *uap; 120 { 121 struct nameidata nd; 122 int error, flags; 123 124 /* Make sure that the caller is root. */ 125 error = suser(td); 126 if (error) 127 return (error); 128 129 mtx_lock(&Giant); 130 /* 131 * If accounting is to be started to a file, open that file for 132 * appending and make sure it's a 'normal'. 133 */ 134 if (SCARG(uap, path) != NULL) { 135 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 136 td); 137 flags = FWRITE | O_APPEND; 138 error = vn_open(&nd, &flags, 0); 139 if (error) 140 goto done2; 141 NDFREE(&nd, NDF_ONLY_PNBUF); 142 VOP_UNLOCK(nd.ni_vp, 0, td); 143 if (nd.ni_vp->v_type != VREG) { 144 vn_close(nd.ni_vp, flags, td->td_ucred, td); 145 error = EACCES; 146 goto done2; 147 } 148 } 149 150 /* 151 * If accounting was previously enabled, kill the old space-watcher, 152 * close the file, and (if no new file was specified, leave). 153 */ 154 if (acctp != NULLVP || savacctp != NULLVP) { 155 callout_stop(&acctwatch_callout); 156 error = vn_close((acctp != NULLVP ? acctp : savacctp), 157 (acctp != NULLVP ? acctflags : savacctflags), 158 td->td_ucred, td); 159 acctp = savacctp = NULLVP; 160 } 161 if (SCARG(uap, path) == NULL) 162 goto done2; 163 164 /* 165 * Save the new accounting file vnode, and schedule the new 166 * free space watcher. 167 */ 168 acctp = nd.ni_vp; 169 acctflags = flags; 170 callout_init(&acctwatch_callout, 0); 171 acctwatch(NULL); 172 done2: 173 mtx_unlock(&Giant); 174 return (error); 175 } 176 177 /* 178 * Write out process accounting information, on process exit. 179 * Data to be written out is specified in Leffler, et al. 180 * and are enumerated below. (They're also noted in the system 181 * "acct.h" header file.) 182 */ 183 184 int 185 acct_process(td) 186 struct thread *td; 187 { 188 struct proc *p = td->td_proc; 189 struct acct acct; 190 struct rusage *r; 191 struct timeval ut, st, tmp; 192 int t; 193 struct vnode *vp; 194 195 /* If accounting isn't enabled, don't bother */ 196 vp = acctp; 197 if (vp == NULLVP) 198 return (0); 199 200 /* 201 * Get process accounting information. 202 */ 203 204 /* (1) The name of the command that ran */ 205 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 206 207 /* (2) The amount of user and system time that was used */ 208 mtx_lock_spin(&sched_lock); 209 calcru(p, &ut, &st, NULL); 210 mtx_unlock_spin(&sched_lock); 211 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 212 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 213 214 /* (3) The elapsed time the commmand ran (and its starting time) */ 215 acct.ac_btime = p->p_stats->p_start.tv_sec; 216 microtime(&tmp); 217 timevalsub(&tmp, &p->p_stats->p_start); 218 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 219 220 /* (4) The average amount of memory used */ 221 r = &p->p_stats->p_ru; 222 tmp = ut; 223 timevaladd(&tmp, &st); 224 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 225 if (t) 226 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 227 else 228 acct.ac_mem = 0; 229 230 /* (5) The number of disk I/O operations done */ 231 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 232 233 /* (6) The UID and GID of the process */ 234 acct.ac_uid = p->p_ucred->cr_ruid; 235 acct.ac_gid = p->p_ucred->cr_rgid; 236 237 /* (7) The terminal from which the process was started */ 238 PROC_LOCK(p); 239 SESS_LOCK(p->p_session); 240 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 241 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev); 242 else 243 acct.ac_tty = NOUDEV; 244 SESS_UNLOCK(p->p_session); 245 PROC_UNLOCK(p); 246 247 /* (8) The boolean flags that tell how the process terminated, etc. */ 248 acct.ac_flag = p->p_acflag; 249 250 /* 251 * Eliminate any file size rlimit. 252 */ 253 if (p->p_limit->p_refcnt > 1 && 254 (p->p_limit->p_lflags & PL_SHAREMOD) == 0) { 255 p->p_limit->p_refcnt--; 256 p->p_limit = limcopy(p->p_limit); 257 } 258 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 259 260 /* 261 * Write the accounting information to the file. 262 */ 263 VOP_LEASE(vp, td, td->td_ucred, LEASE_WRITE); 264 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 265 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, td->td_ucred, 266 (int *)0, td)); 267 } 268 269 /* 270 * Encode_comp_t converts from ticks in seconds and microseconds 271 * to ticks in 1/AHZ seconds. The encoding is described in 272 * Leffler, et al., on page 63. 273 */ 274 275 #define MANTSIZE 13 /* 13 bit mantissa. */ 276 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 277 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 278 279 static comp_t 280 encode_comp_t(s, us) 281 u_long s, us; 282 { 283 int exp, rnd; 284 285 exp = 0; 286 rnd = 0; 287 s *= AHZ; 288 s += us / (1000000 / AHZ); /* Maximize precision. */ 289 290 while (s > MAXFRACT) { 291 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 292 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 293 exp++; 294 } 295 296 /* If we need to round up, do it (and handle overflow correctly). */ 297 if (rnd && (++s > MAXFRACT)) { 298 s >>= EXPSIZE; 299 exp++; 300 } 301 302 /* Clean it up and polish it off. */ 303 exp <<= MANTSIZE; /* Shift the exponent into place */ 304 exp += s; /* and add on the mantissa. */ 305 return (exp); 306 } 307 308 /* 309 * Periodically check the filesystem to see if accounting 310 * should be turned on or off. Beware the case where the vnode 311 * has been vgone()'d out from underneath us, e.g. when the file 312 * system containing the accounting file has been forcibly unmounted. 313 */ 314 /* ARGSUSED */ 315 static void 316 acctwatch(a) 317 void *a; 318 { 319 struct statfs sb; 320 321 if (savacctp != NULLVP) { 322 if (savacctp->v_type == VBAD) { 323 (void) vn_close(savacctp, savacctflags, NOCRED, NULL); 324 savacctp = NULLVP; 325 return; 326 } 327 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct thread *)0); 328 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 329 acctp = savacctp; 330 acctflags = savacctflags; 331 savacctp = NULLVP; 332 log(LOG_NOTICE, "Accounting resumed\n"); 333 } 334 } else { 335 if (acctp == NULLVP) 336 return; 337 if (acctp->v_type == VBAD) { 338 (void) vn_close(acctp, acctflags, NOCRED, NULL); 339 acctp = NULLVP; 340 return; 341 } 342 (void)VFS_STATFS(acctp->v_mount, &sb, (struct thread *)0); 343 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 344 savacctp = acctp; 345 savacctflags = acctflags; 346 acctp = NULLVP; 347 log(LOG_NOTICE, "Accounting suspended\n"); 348 } 349 } 350 callout_reset(&acctwatch_callout, acctchkfreq * hz, acctwatch, NULL); 351 } 352