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