1 /* $OpenBSD: kern_acct.c,v 1.22 2010/01/14 23:12:11 schwarze Exp $ */ 2 /* $NetBSD: kern_acct.c,v 1.42 1996/02/04 02:15:12 christos Exp $ */ 3 4 /*- 5 * Copyright (c) 1994 Christopher G. Demetriou 6 * Copyright (c) 1982, 1986, 1989, 1993 7 * The Regents of the University of California. All rights reserved. 8 * (c) UNIX System Laboratories, Inc. 9 * All or some portions of this file are derived from material licensed 10 * to the University of California by American Telephone and Telegraph 11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 12 * the permission of UNIX System Laboratories, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/proc.h> 44 #include <sys/mount.h> 45 #include <sys/vnode.h> 46 #include <sys/file.h> 47 #include <sys/syslog.h> 48 #include <sys/kernel.h> 49 #include <sys/namei.h> 50 #include <sys/errno.h> 51 #include <sys/acct.h> 52 #include <sys/resourcevar.h> 53 #include <sys/ioctl.h> 54 #include <sys/tty.h> 55 #include <sys/kthread.h> 56 57 #include <sys/syscallargs.h> 58 59 /* 60 * The routines implemented in this file are described in: 61 * Leffler, et al.: The Design and Implementation of the 4.3BSD 62 * UNIX Operating System (Addison Welley, 1989) 63 * on pages 62-63. 64 * 65 * Arguably, to simplify accounting operations, this mechanism should 66 * be replaced by one in which an accounting log file (similar to /dev/klog) 67 * is read by a user process, etc. However, that has its own problems. 68 */ 69 70 /* 71 * Internal accounting functions. 72 */ 73 comp_t encode_comp_t(u_long, u_long); 74 int acct_start(void); 75 void acct_thread(void *); 76 void acct_shutdown(void); 77 78 /* 79 * Accounting vnode pointer, and saved vnode pointer. 80 */ 81 struct vnode *acctp; 82 struct vnode *savacctp; 83 84 /* 85 * Values associated with enabling and disabling accounting 86 */ 87 int acctsuspend = 2; /* stop accounting when < 2% free space left */ 88 int acctresume = 4; /* resume when free space risen to > 4% */ 89 int acctchkfreq = 15; /* frequency (in seconds) to check space */ 90 91 struct proc *acct_proc; 92 93 /* 94 * Accounting system call. Written based on the specification and 95 * previous implementation done by Mark Tinguely. 96 */ 97 int 98 sys_acct(struct proc *p, void *v, register_t *retval) 99 { 100 struct sys_acct_args /* { 101 syscallarg(const char *) path; 102 } */ *uap = v; 103 struct nameidata nd; 104 int error; 105 106 /* Make sure that the caller is root. */ 107 if ((error = suser(p, 0)) != 0) 108 return (error); 109 110 /* 111 * If accounting is to be started to a file, open that file for 112 * writing and make sure it's 'normal'. 113 */ 114 if (SCARG(uap, path) != NULL) { 115 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), 116 p); 117 if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0) 118 return (error); 119 VOP_UNLOCK(nd.ni_vp, 0, p); 120 if (nd.ni_vp->v_type != VREG) { 121 vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 122 return (EACCES); 123 } 124 } 125 126 /* 127 * If accounting was previously enabled, kill the old space-watcher, 128 * close the file, and (if no new file was specified, leave). 129 */ 130 if (acctp != NULL || savacctp != NULL) { 131 wakeup(&acct_proc); 132 error = vn_close((acctp != NULL ? acctp : savacctp), FWRITE, 133 p->p_ucred, p); 134 acctp = savacctp = NULL; 135 } 136 if (SCARG(uap, path) == NULL) 137 return (0); 138 139 /* 140 * Save the new accounting file vnode, and schedule the new 141 * free space watcher. 142 */ 143 acctp = nd.ni_vp; 144 if ((error = acct_start()) != 0) { 145 acctp = NULL; 146 (void)vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); 147 return (error); 148 } 149 return (0); 150 } 151 152 /* 153 * Write out process accounting information, on process exit. 154 * Data to be written out is specified in Leffler, et al. 155 * and are enumerated below. (They're also noted in the system 156 * "acct.h" header file.) 157 */ 158 int 159 acct_process(struct proc *p) 160 { 161 struct acct acct; 162 struct rusage *r; 163 struct timeval ut, st, tmp; 164 int t; 165 struct vnode *vp; 166 struct plimit *oplim = NULL; 167 int error; 168 169 /* If accounting isn't enabled, don't bother */ 170 vp = acctp; 171 if (vp == NULL) 172 return (0); 173 174 /* 175 * Raise the file limit so that accounting can't be stopped by the 176 * user. (XXX - we should think about the cpu limit too). 177 */ 178 if (p->p_p->ps_limit->p_refcnt > 1) { 179 oplim = p->p_p->ps_limit; 180 p->p_p->ps_limit = limcopy(p->p_p->ps_limit); 181 } 182 p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; 183 184 /* 185 * Get process accounting information. 186 */ 187 188 /* (1) The name of the command that ran */ 189 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); 190 191 /* (2) The amount of user and system time that was used */ 192 calcru(p, &ut, &st, NULL); 193 acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); 194 acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); 195 196 /* (3) The elapsed time the command ran (and its starting time) */ 197 acct.ac_btime = p->p_stats->p_start.tv_sec; 198 getmicrotime(&tmp); 199 timersub(&tmp, &p->p_stats->p_start, &tmp); 200 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); 201 202 /* (4) The average amount of memory used */ 203 r = &p->p_stats->p_ru; 204 timeradd(&ut, &st, &tmp); 205 t = tmp.tv_sec * hz + tmp.tv_usec / tick; 206 if (t) 207 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; 208 else 209 acct.ac_mem = 0; 210 211 /* (5) The number of disk I/O operations done */ 212 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); 213 214 /* (6) The UID and GID of the process */ 215 acct.ac_uid = p->p_cred->p_ruid; 216 acct.ac_gid = p->p_cred->p_rgid; 217 218 /* (7) The terminal from which the process was started */ 219 if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) 220 acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; 221 else 222 acct.ac_tty = NODEV; 223 224 /* (8) The boolean flags that tell how the process terminated, etc. */ 225 acct.ac_flag = p->p_acflag; 226 227 /* 228 * Now, just write the accounting information to the file. 229 */ 230 error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), 231 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, NULL, p); 232 233 if (oplim) { 234 limfree(p->p_p->ps_limit); 235 p->p_p->ps_limit = oplim; 236 } 237 238 return error; 239 } 240 241 /* 242 * Encode_comp_t converts from ticks in seconds and microseconds 243 * to ticks in 1/AHZ seconds. The encoding is described in 244 * Leffler, et al., on page 63. 245 */ 246 247 #define MANTSIZE 13 /* 13 bit mantissa. */ 248 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ 249 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ 250 251 comp_t 252 encode_comp_t(u_long s, u_long us) 253 { 254 int exp, rnd; 255 256 exp = 0; 257 rnd = 0; 258 s *= AHZ; 259 s += us / (1000000 / AHZ); /* Maximize precision. */ 260 261 while (s > MAXFRACT) { 262 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ 263 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ 264 exp++; 265 } 266 267 /* If we need to round up, do it (and handle overflow correctly). */ 268 if (rnd && (++s > MAXFRACT)) { 269 s >>= EXPSIZE; 270 exp++; 271 } 272 273 /* Clean it up and polish it off. */ 274 exp <<= MANTSIZE; /* Shift the exponent into place */ 275 exp += s; /* and add on the mantissa. */ 276 return (exp); 277 } 278 279 int 280 acct_start(void) 281 { 282 /* Already running. */ 283 if (acct_proc != NULL) 284 return (0); 285 286 return (kthread_create(acct_thread, NULL, &acct_proc, "acct")); 287 } 288 289 /* 290 * Periodically check the file system to see if accounting 291 * should be turned on or off. Beware the case where the vnode 292 * has been vgone()'d out from underneath us, e.g. when the file 293 * system containing the accounting file has been forcibly unmounted. 294 */ 295 /* ARGSUSED */ 296 void 297 acct_thread(void *arg) 298 { 299 struct statfs sb; 300 struct proc *p = curproc; 301 302 for (;;) { 303 if (savacctp != NULL) { 304 if (savacctp->v_type == VBAD) { 305 (void) vn_close(savacctp, FWRITE, NOCRED, p); 306 savacctp = NULL; 307 break; 308 } 309 (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); 310 if (sb.f_bavail > acctresume * sb.f_blocks / 100) { 311 acctp = savacctp; 312 savacctp = NULL; 313 log(LOG_NOTICE, "Accounting resumed\n"); 314 } 315 } else if (acctp != NULL) { 316 if (acctp->v_type == VBAD) { 317 (void) vn_close(acctp, FWRITE, NOCRED, p); 318 acctp = NULL; 319 break; 320 } 321 (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); 322 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { 323 savacctp = acctp; 324 acctp = NULL; 325 log(LOG_NOTICE, "Accounting suspended\n"); 326 } 327 } else { 328 break; 329 } 330 tsleep(&acct_proc, PPAUSE, "acct", acctchkfreq *hz); 331 } 332 acct_proc = NULL; 333 kthread_exit(0); 334 } 335 336 void 337 acct_shutdown(void) 338 { 339 340 struct proc *p = curproc; 341 342 if (acctp != NULL || savacctp != NULL) { 343 vn_close((acctp != NULL ? acctp : savacctp), FWRITE, 344 NOCRED, p); 345 acctp = savacctp = NULL; 346 } 347 } 348