/* $NetBSD: kern_acct.c,v 1.102 2026/01/03 23:57:36 riastradh Exp $ */ /*- * 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 8.8 (Berkeley) 5/14/95 */ /*- * Copyright (c) 1994 Christopher G. Demetriou * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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 8.8 (Berkeley) 5/14/95 */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: kern_acct.c,v 1.102 2026/01/03 23:57:36 riastradh Exp $"); #include <sys/param.h> #include <sys/types.h> #include <sys/acct.h> #include <sys/errno.h> #include <sys/file.h> #include <sys/ioctl.h> #include <sys/kauth.h> #include <sys/kernel.h> #include <sys/kmem.h> #include <sys/kthread.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/proc.h> #include <sys/resourcevar.h> #include <sys/sdt.h> #include <sys/syscallargs.h> #include <sys/syslog.h> #include <sys/systm.h> #include <sys/tty.h> #include <sys/vnode.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. */ /* * Lock to serialize system calls and kernel threads. */ krwlock_t acct_lock; /* * The global accounting state and related data. Gain the mutex before * accessing these variables. */ static enum { ACCT_STOP, ACCT_ACTIVE, ACCT_SUSPENDED } acct_state; /* The current accounting state. */ static struct vnode *acct_vp; /* Accounting vnode pointer. */ static kauth_cred_t acct_cred; /* Credential of accounting file owner (i.e root). Used when accounting file i/o. */ static struct lwp *acct_dkwatcher; /* Free disk space checker. */ /* * 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 */ /* * 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. */ static 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); } static int acct_chkfree(void) { int error; struct statvfs *sb; fsblkcnt_t bavail; sb = kmem_alloc(sizeof(*sb), KM_SLEEP); error = VFS_STATVFS(acct_vp->v_mount, sb); if (error != 0) { kmem_free(sb, sizeof(*sb)); return (error); } if (sb->f_bfree < sb->f_bresvd) { bavail = 0; } else { bavail = sb->f_bfree - sb->f_bresvd; } switch (acct_state) { case ACCT_SUSPENDED: if (bavail > acctresume * sb->f_blocks / 100) { acct_state = ACCT_ACTIVE; log(LOG_NOTICE, "Accounting resumed\n"); } break; case ACCT_ACTIVE: if (bavail <= acctsuspend * sb->f_blocks / 100) { acct_state = ACCT_SUSPENDED; log(LOG_NOTICE, "Accounting suspended\n"); } break; case ACCT_STOP: break; } kmem_free(sb, sizeof(*sb)); return (0); } static void acct_stop(void) { int error; KASSERT(rw_write_held(&acct_lock)); if (acct_vp != NULLVP && acct_vp->v_type != VBAD) { error = vn_close(acct_vp, FWRITE, acct_cred); #ifdef DIAGNOSTIC if (error != 0) printf("acct_stop: failed to close, errno = %d\n", error); #else __USE(error); #endif acct_vp = NULLVP; } if (acct_cred != NULL) { kauth_cred_free(acct_cred); acct_cred = NULL; } acct_state = ACCT_STOP; } /* * 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. */ static void acctwatch(void *arg) { int error; log(LOG_NOTICE, "Accounting started\n"); rw_enter(&acct_lock, RW_WRITER); while (acct_state != ACCT_STOP) { if (acct_vp->v_type == VBAD) { log(LOG_NOTICE, "Accounting terminated\n"); acct_stop(); continue; } error = acct_chkfree(); #ifdef DIAGNOSTIC if (error != 0) printf("acctwatch: failed to statvfs, error = %d\n", error); #else __USE(error); #endif rw_exit(&acct_lock); error = kpause("actwat", false, acctchkfreq * hz, NULL); rw_enter(&acct_lock, RW_WRITER); #ifdef DIAGNOSTIC if (error != 0 && error != EWOULDBLOCK) printf("acctwatch: sleep error %d\n", error); #endif } acct_dkwatcher = NULL; rw_exit(&acct_lock); kthread_exit(0); } void acct_init(void) { acct_state = ACCT_STOP; acct_vp = NULLVP; acct_cred = NULL; rw_init(&acct_lock); } /* * Accounting system call. Written based on the specification and * previous implementation done by Mark Tinguely. */ int sys_acct(struct lwp *l, const struct sys_acct_args *uap, register_t *retval) { /* { syscallarg(const char *) path; } */ struct pathbuf *pb; struct vnode *vp; int error; /* Make sure that the caller is root. */ if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_ACCOUNTING, 0, NULL, NULL, NULL))) return (error); /* * If accounting is to be started to a file, open that file for * writing and make sure it's a 'normal'. */ if (SCARG(uap, path) != NULL) { struct vattr va; size_t pad; error = pathbuf_copyin(SCARG(uap, path), &pb); if (error) { return error; } error = vn_open(NULL, pb, TRYEMULROOT, FWRITE|O_APPEND, 0, &vp, NULL, NULL); if (error != 0) { pathbuf_destroy(pb); return error; } if (vp->v_type != VREG) { VOP_UNLOCK(vp); error = SET_ERROR(EACCES); goto bad; } if ((error = VOP_GETATTR(vp, &va, l->l_cred)) != 0) { VOP_UNLOCK(vp); goto bad; } if ((pad = (va.va_size % sizeof(struct acct))) != 0) { u_quad_t size = va.va_size - pad; #ifdef DIAGNOSTIC printf("Size of accounting file not a multiple of " "%lu - incomplete record truncated\n", (unsigned long)sizeof(struct acct)); #endif vattr_null(&va); va.va_size = size; error = VOP_SETATTR(vp, &va, l->l_cred); if (error != 0) { VOP_UNLOCK(vp); goto bad; } } VOP_UNLOCK(vp); } rw_enter(&acct_lock, RW_WRITER); /* * If accounting was previously enabled, kill the old space-watcher, * free credential for accounting file i/o, * ... (and, if no new file was specified, leave). */ acct_stop(); if (SCARG(uap, path) == NULL) goto out; /* * Save the new accounting file vnode and credential, * and schedule the new free space watcher. */ acct_state = ACCT_ACTIVE; acct_vp = vp; acct_cred = l->l_cred; kauth_cred_hold(acct_cred); pathbuf_destroy(pb); error = acct_chkfree(); /* Initial guess. */ if (error != 0) { acct_stop(); goto out; } if (acct_dkwatcher == NULL) { error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, acctwatch, NULL, &acct_dkwatcher, "acctwatch"); if (error != 0) acct_stop(); } out: rw_exit(&acct_lock); return (error); bad: vn_close(vp, FWRITE, l->l_cred); pathbuf_destroy(pb); return error; } /* * 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 lwp *l) { struct acct acct; struct timeval ut, st, tmp; struct rusage *r; int t, error = 0; struct rlimit orlim; struct proc *p = l->l_proc; if (acct_state != ACCT_ACTIVE) return 0; memset(&acct, 0, sizeof(acct)); /* to zerofill padded data */ rw_enter(&acct_lock, RW_READER); /* If accounting isn't enabled, don't bother */ if (acct_state != ACCT_ACTIVE) goto out; /* * Temporarily raise the file limit so that accounting can't * be stopped by the user. * * XXX We should think about the CPU limit, too. */ lim_privatise(p); orlim = p->p_rlimit[RLIMIT_FSIZE]; /* Set current and max to avoid illegal values */ p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; p->p_rlimit[RLIMIT_FSIZE].rlim_max = RLIM_INFINITY; /* * Get process accounting information. */ /* (1) The name of the command that ran */ strncpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm)); /* (2) The amount of user and system time that was used */ mutex_enter(p->p_lock); calcru(p, &ut, &st, NULL, NULL); mutex_exit(p->p_lock); 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 command 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 = kauth_cred_getuid(l->l_cred); acct.ac_gid = kauth_cred_getgid(l->l_cred); /* (7) The terminal from which the process was started */ mutex_enter(&proc_lock); if ((p->p_lflag & PL_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; mutex_exit(&proc_lock); /* (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, acct_vp, (void *)&acct, sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, acct_cred, NULL, NULL); if (error != 0) log(LOG_ERR, "Accounting: write failed %d\n", error); /* Restore limit - rather pointless since process is about to exit */ p->p_rlimit[RLIMIT_FSIZE] = orlim; out: rw_exit(&acct_lock); return (error); }
