/* $OpenBSD: kern_acct.c,v 1.21 2007/04/12 22:14:15 tedu Exp $ */ /* $NetBSD: kern_acct.c,v 1.42 1996/02/04 02:15:12 christos Exp $ */ /*- * Copyright (c) 1994 Christopher G. Demetriou * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93 */ #include <sys/param.h> #include <sys/systm.h> #include <sys/proc.h> #include <sys/mount.h> #include <sys/vnode.h> #include <sys/file.h> #include <sys/syslog.h> #include <sys/kernel.h> #include <sys/namei.h> #include <sys/errno.h> #include <sys/acct.h> #include <sys/resourcevar.h> #include <sys/ioctl.h> #include <sys/tty.h> #include <sys/kthread.h> #include <sys/syscallargs.h> /* * The routines implemented in this file are described in: * Leffler, et al.: The Design and Implementation of the 4.3BSD * UNIX Operating System (Addison Welley, 1989) * on pages 62-63. * * Arguably, to simplify accounting operations, this mechanism should * be replaced by one in which an accounting log file (similar to /dev/klog) * is read by a user process, etc. However, that has its own problems. */ /* * Internal accounting functions. */ comp_t encode_comp_t(u_long, u_long); int acct_start(void); void acct_thread(void *); void acct_shutdown(void); /* * Accounting vnode pointer, and saved vnode pointer. */ struct vnode *acctp; struct vnode *savacctp; /* * Values associated with enabling and disabling accounting */ int acctsuspend = 2; /* stop accounting when < 2% free space left */ int acctresume = 4; /* resume when free space risen to > 4% */ int acctchkfreq = 15; /* frequency (in seconds) to check space */ struct proc *acct_proc; /* * Accounting system call. Written based on the specification and * previous implementation done by Mark Tinguely. */ int sys_acct(struct proc *p, void *v, register_t *retval) { struct sys_acct_args /* { syscallarg(const char *) path; } */ *uap = v; struct nameidata nd; int error; /* Make sure that the caller is root. */ if ((error = suser(p, 0)) != 0) return (error); /* * If accounting is to be started to a file, open that file for * writing and make sure it's 'normal'. */ if (SCARG(uap, path) != NULL) { NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0) return (error); VOP_UNLOCK(nd.ni_vp, 0, p); if (nd.ni_vp->v_type != VREG) { vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); return (EACCES); } } /* * If accounting was previously enabled, kill the old space-watcher, * close the file, and (if no new file was specified, leave). */ if (acctp != NULL || savacctp != NULL) { wakeup(&acct_proc); error = vn_close((acctp != NULL ? acctp : savacctp), FWRITE, p->p_ucred, p); acctp = savacctp = NULL; } if (SCARG(uap, path) == NULL) return (0); /* * Save the new accounting file vnode, and schedule the new * free space watcher. */ acctp = nd.ni_vp; if ((error = acct_start()) != 0) { acctp = NULL; (void)vn_close(nd.ni_vp, FWRITE, p->p_ucred, p); return (error); } return (0); } /* * Write out process accounting information, on process exit. * Data to be written out is specified in Leffler, et al. * and are enumerated below. (They're also noted in the system * "acct.h" header file.) */ int acct_process(struct proc *p) { struct acct acct; struct rusage *r; struct timeval ut, st, tmp; int t; struct vnode *vp; struct plimit *oplim = NULL; int error; /* If accounting isn't enabled, don't bother */ vp = acctp; if (vp == NULL) return (0); /* * Raise the file limit so that accounting can't be stopped by the * user. (XXX - we should think about the cpu limit too). */ if (p->p_p->ps_limit->p_refcnt > 1) { oplim = p->p_p->ps_limit; p->p_p->ps_limit = limcopy(p->p_p->ps_limit); } p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; /* * Get process accounting information. */ /* (1) The name of the command that ran */ bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm); /* (2) The amount of user and system time that was used */ calcru(p, &ut, &st, NULL); acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec); acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec); /* (3) The elapsed time the commmand ran (and its starting time) */ acct.ac_btime = p->p_stats->p_start.tv_sec; getmicrotime(&tmp); timersub(&tmp, &p->p_stats->p_start, &tmp); acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec); /* (4) The average amount of memory used */ r = &p->p_stats->p_ru; timeradd(&ut, &st, &tmp); t = tmp.tv_sec * hz + tmp.tv_usec / tick; if (t) acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t; else acct.ac_mem = 0; /* (5) The number of disk I/O operations done */ acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0); /* (6) The UID and GID of the process */ acct.ac_uid = p->p_cred->p_ruid; acct.ac_gid = p->p_cred->p_rgid; /* (7) The terminal from which the process was started */ if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp) acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev; else acct.ac_tty = NODEV; /* (8) The boolean flags that tell how the process terminated, etc. */ acct.ac_flag = p->p_acflag; /* * Now, just write the accounting information to the file. */ error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred, NULL, p); if (oplim) { limfree(p->p_p->ps_limit); p->p_p->ps_limit = oplim; } return error; } /* * Encode_comp_t converts from ticks in seconds and microseconds * to ticks in 1/AHZ seconds. The encoding is described in * Leffler, et al., on page 63. */ #define MANTSIZE 13 /* 13 bit mantissa. */ #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ comp_t encode_comp_t(u_long s, u_long us) { int exp, rnd; exp = 0; rnd = 0; s *= AHZ; s += us / (1000000 / AHZ); /* Maximize precision. */ while (s > MAXFRACT) { rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */ s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ exp++; } /* If we need to round up, do it (and handle overflow correctly). */ if (rnd && (++s > MAXFRACT)) { s >>= EXPSIZE; exp++; } /* Clean it up and polish it off. */ exp <<= MANTSIZE; /* Shift the exponent into place */ exp += s; /* and add on the mantissa. */ return (exp); } int acct_start(void) { /* Already running. */ if (acct_proc != NULL) return (0); return (kthread_create(acct_thread, NULL, &acct_proc, "acct")); } /* * Periodically check the file system to see if accounting * should be turned on or off. Beware the case where the vnode * has been vgone()'d out from underneath us, e.g. when the file * system containing the accounting file has been forcibly unmounted. */ /* ARGSUSED */ void acct_thread(void *arg) { struct statfs sb; struct proc *p = curproc; for (;;) { if (savacctp != NULL) { if (savacctp->v_type == VBAD) { (void) vn_close(savacctp, FWRITE, NOCRED, p); savacctp = NULL; break; } (void)VFS_STATFS(savacctp->v_mount, &sb, (struct proc *)0); if (sb.f_bavail > acctresume * sb.f_blocks / 100) { acctp = savacctp; savacctp = NULL; log(LOG_NOTICE, "Accounting resumed\n"); } } else if (acctp != NULL) { if (acctp->v_type == VBAD) { (void) vn_close(acctp, FWRITE, NOCRED, p); acctp = NULL; break; } (void)VFS_STATFS(acctp->v_mount, &sb, (struct proc *)0); if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) { savacctp = acctp; acctp = NULL; log(LOG_NOTICE, "Accounting suspended\n"); } } else { break; } tsleep(&acct_proc, PPAUSE, "acct", acctchkfreq *hz); } acct_proc = NULL; kthread_exit(0); } void acct_shutdown(void) { struct proc *p = curproc; if (acctp != NULL || savacctp != NULL) { vn_close((acctp != NULL ? acctp : savacctp), FWRITE, NOCRED, p); acctp = savacctp = NULL; } }