Annotation of sys/kern/kern_acct.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: kern_acct.c,v 1.21 2007/04/12 22:14:15 tedu 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 commmand 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: }
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