/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2013 Gary Mills
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright 2020 Joyent, Inc.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*
 * This is the new whodo command which takes advantage of
 * the /proc interface to gain access to the information
 * of all the processes currently on the system.
 *
 * Maintenance note:
 *
 * Much of this code is replicated in w.c.  If you're
 * fixing bugs here, then you should probably fix 'em there too.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#include <time.h>
#include <err.h>
#include <errno.h>
#include <sys/types.h>
#include <utmpx.h>
#include <sys/sysmacros.h>
#include <sys/utsname.h>
#include <sys/stat.h>
#include <sys/mkdev.h>
#include <dirent.h>
#include <procfs.h>             /* /proc header file */
#include <sys/wait.h>
#include <locale.h>
#include <unistd.h>
#include <limits.h>
#include <priv_utils.h>

/*
 * Use the full lengths from utmpx for user and line.
 */
#define NMAX    (sizeof (((struct utmpx *)0)->ut_user))
#define LMAX    (sizeof (((struct utmpx *)0)->ut_line))

/* Print minimum field widths. */
#define LOGIN_WIDTH     8
#define LINE_WIDTH      8

#define DIV60(t)        ((t+30)/60)    /* x/60 rounded */

#ifdef ERR
#undef ERR
#endif
#define ERR             (-1)

#define DEVNAMELEN      14
#define HSIZE           256             /* size of process hash table */
#define PROCDIR         "/proc"
#define INITPROCESS     (pid_t)1        /* init process pid */
#define NONE            'n'             /* no state */
#define RUNNING         'r'             /* runnable process */
#define ZOMBIE          'z'             /* zombie process */
#define VISITED         'v'             /* marked node as visited */

static uint_t   ndevs;                  /* number of configured devices */
static uint_t   maxdev;                 /* slots for configured devices */
#define DNINCR  100
static struct devl {                    /* device list   */
        char    dname[DEVNAMELEN];      /* device name   */
        dev_t   ddev;                   /* device number */
} *devl;

struct uproc {
        pid_t   p_upid;                 /* user process id */
        char    p_state;                /* numeric value of process state */
        dev_t   p_ttyd;                 /* controlling tty of process */
        time_t  p_time;                 /* ticks of user & system time */
        time_t  p_ctime;                /* ticks of child user & system time */
        int     p_igintr;               /* 1=ignores SIGQUIT and SIGINT */
        char    p_comm[PRARGSZ+1];      /* command */
        char    p_args[PRARGSZ+1];      /* command line arguments */
        struct uproc    *p_child,       /* first child pointer */
                        *p_sibling,     /* sibling pointer */
                        *p_pgrplink,    /* pgrp link */
                        *p_link;        /* hash table chain pointer */
};

/*
 *      define  hash table for struct uproc
 *      Hash function uses process id
 *      and the size of the hash table(HSIZE)
 *      to determine process index into the table.
 */
static struct uproc     pr_htbl[HSIZE];

static struct   uproc   *findhash(pid_t);
static time_t   findidle(char *);
static void     clnarglist(char *);
static void     showproc(struct uproc *);
static void     showtotals(struct uproc *);
static void     calctotals(struct uproc *);
static char     *getty(dev_t);
static void     prttime(time_t, int);
static void     prtat(time_t *);

static int      priv_proc_open(const char *, int);
static int      priv_proc_openat(int, const char *, int);
static boolean_t do_proc_read(int, void *, size_t);

static char     *prog;
static int      header = 1;     /* true if -h flag: don't print heading */
static int      lflag = 0;      /* true if -l flag: w command format */
static char     *sel_user;      /* login of particular user selected */
static time_t   now;            /* current time of day */
static time_t   uptime;         /* time of last reboot & elapsed time since */
static int      nusers;         /* number of users logged in now */
static time_t   idle;           /* number of minutes user is idle */
static time_t   jobtime;        /* total cpu time visible */
static char     doing[520];     /* process attached to terminal */
static time_t   proctime;       /* cpu time of process in doing */
static int      empty;
static pid_t    curpid;

/*
 * Basic privs we never need and can drop. This is likely not exhaustive,
 * but should significantly reduce any potential attack surfaces.
 */
static const char *drop_privs[] = {
        PRIV_FILE_WRITE,
        PRIV_NET_ACCESS,
        PRIV_PROC_EXEC,
        PRIV_PROC_FORK,
        PRIV_FILE_LINK_ANY
};

#if SIGQUIT > SIGINT
#define ACTSIZE SIGQUIT
#else
#define ACTSIZE SIGINT
#endif

int
main(int argc, char *argv[])
{
        struct utmpx    *ut;
        struct utmpx    *utmpbegin;
        struct utmpx    *utmpend;
        struct utmpx    *utp;
        struct tm               *tm;
        struct uproc    *up, *parent, *pgrp;
        struct psinfo   info;
        struct sigaction actinfo[ACTSIZE];
        struct pstatus  statinfo;
        struct stat     sbuf;
        struct utsname  uts;
        DIR             *dirp;
        struct  dirent  *dp;
        char            pname[PATH_MAX];
        int             procfd, dirfd;
        int             i;
        int             days, hrs, mins;
        int             entries;
        priv_set_t      *pset;

        if (__init_suid_priv(PU_CLEARLIMITSET, PRIV_PROC_OWNER, NULL) != 0) {
                err(EXIT_FAILURE, "failed to enable privilege bracketing");
        }

        /*
         * After setting up privilege bracketing, we can further reduce the
         * privileges in use. The effective set is set to the basic set minus
         * the privs in drop_privs. The permitted set is the effective set
         * plus PRIV_PROC_OWNER (i.e. the privilege being bracketed).
         */
        pset = priv_allocset();
        if (pset == NULL)
                err(EXIT_FAILURE, "priv_allocset failed");

        priv_basicset(pset);
        for (i = 0; i < ARRAY_SIZE(drop_privs); i++) {
                if (priv_delset(pset, drop_privs[i]) != 0) {
                        err(EXIT_FAILURE,
                            "failed to remove %s privilege from privilege set",
                            drop_privs[i]);
                }
        }

        if (setppriv(PRIV_SET, PRIV_EFFECTIVE, pset) < 0)
                err(EXIT_FAILURE, "failed setting effective privilege set");

        if (priv_addset(pset, PRIV_PROC_OWNER) != 0) {
                err(EXIT_FAILURE,
                    "failed to add PRIV_PROC_OWNER privilege to privilege set");
        }

        if (setppriv(PRIV_SET, PRIV_PERMITTED, pset) < 0)
                err(EXIT_FAILURE, "failed to set permitted privilege set");

        /*
         * Unfortunately, when run as root, privilege bracketing is a no-op,
         * so we have to add PRIV_PROC_OWNER into our effective set for things
         * to work.
         */
        if (getuid() == 0 && setppriv(PRIV_SET, PRIV_EFFECTIVE, pset) < 0) {
                err(EXIT_FAILURE, "failed to set effective privilege set");
        }

        priv_freeset(pset);
        pset = NULL;

        (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN "SYS_TEST"
#endif
        (void) textdomain(TEXT_DOMAIN);

        prog = argv[0];

        while (argc > 1) {
                if (argv[1][0] == '-') {
                        for (i = 1; argv[1][i]; i++) {
                                switch (argv[1][i]) {

                                case 'h':
                                        header = 0;
                                        break;

                                case 'l':
                                        lflag++;
                                        break;

                                default:
                                        (void) printf(gettext(
                                            "usage: %s [ -hl ] [ user ]\n"),
                                            prog);
                                        exit(1);
                                }
                        }
                } else {
                        if (!isalnum(argv[1][0]) || argc > 2) {
                                (void) printf(gettext(
                                    "usage: %s [ -hl ] [ user ]\n"), prog);
                                exit(1);
                        } else
                                sel_user = argv[1];
                }
                argc--; argv++;
        }

        /*
         * read the UTMPX_FILE (contains information about
         * each logged in user)
         */
        if (stat(UTMPX_FILE, &sbuf) < 0)
                err(EXIT_FAILURE, gettext("stat error of %s"), UTMPX_FILE);

        entries = sbuf.st_size / sizeof (struct futmpx);

        if ((ut = calloc(entries, sizeof (struct utmpx))) == NULL)
                err(EXIT_FAILURE, gettext("calloc error of %s"), UTMPX_FILE);

        (void) utmpxname(UTMPX_FILE);

        utmpbegin = ut;
        utmpend = utmpbegin + entries;

        setutxent();
        while ((ut < utmpend) && ((utp = getutxent()) != NULL))
                (void) memcpy(ut++, utp, sizeof (*ut));
        endutxent();

        (void) time(&now);      /* get current time */

        if (header) {   /* print a header */
                if (lflag) {    /* w command format header */
                        prtat(&now);
                        for (ut = utmpbegin; ut < utmpend; ut++) {
                                if (ut->ut_type == USER_PROCESS) {
                                        nusers++;
                                } else if (ut->ut_type == BOOT_TIME) {
                                        uptime = now - ut->ut_xtime;
                                        uptime += 30;
                                        days = uptime / (60*60*24);
                                        uptime %= (60*60*24);
                                        hrs = uptime / (60*60);
                                        uptime %= (60*60);
                                        mins = uptime / 60;

                                        (void) printf(dcgettext(NULL,
                                            "up %d day(s), %d hr(s), "
                                            "%d min(s)", LC_TIME),
                                            days, hrs, mins);
                                }
                        }

                        ut = utmpbegin; /* rewind utmp data */
                        (void) printf(dcgettext(NULL,
                            "  %d user(s)\n", LC_TIME), nusers);
                        (void) printf(dcgettext(NULL, "User     tty      "
                            "login@         idle    JCPU    PCPU what\n",
                            LC_TIME));
                } else {        /* standard whodo header */
                        char date_buf[100];

                        /*
                         * print current time and date
                         */
                        (void) strftime(date_buf, sizeof (date_buf),
                            "%c", localtime(&now));
                        (void) printf("%s\n", date_buf);

                        /*
                         * print system name
                         */
                        (void) uname(&uts);
                        (void) printf("%s\n", uts.nodename);
                }
        }

        /*
         * loop through /proc, reading info about each process
         * and build the parent/child tree
         */
        if ((dirp = opendir(PROCDIR)) == NULL)
                err(EXIT_FAILURE, gettext("could not open %s"), PROCDIR);

        while ((dp = readdir(dirp)) != NULL) {
                if (dp->d_name[0] == '.')
                        continue;

                if (snprintf(pname, sizeof (pname), "%s/%s", PROCDIR,
                    dp->d_name) > sizeof (pname))
                        continue;

                dirfd = priv_proc_open(pname, O_RDONLY | O_DIRECTORY);

                if (dirfd < 0)
                        continue;

                procfd = priv_proc_openat(dirfd, "psinfo", O_RDONLY);
                if (procfd < 0) {
                        (void) close(dirfd);
                        continue;
                }

                if (!do_proc_read(procfd, &info, sizeof (info))) {
                        warn(gettext("read() failed on %s"), pname);
                        (void) close(dirfd);
                        continue;
                }
                (void) close(procfd);

                up = findhash(info.pr_pid);
                up->p_ttyd = info.pr_ttydev;
                up->p_state = (info.pr_nlwp == 0? ZOMBIE : RUNNING);
                up->p_time = 0;
                up->p_ctime = 0;
                up->p_igintr = 0;
                (void) strlcpy(up->p_comm, info.pr_fname,
                    sizeof (up->p_comm));
                up->p_args[0] = 0;

                if (up->p_state != NONE && up->p_state != ZOMBIE) {
                        procfd = priv_proc_openat(dirfd, "status", O_RDONLY);
                        if (procfd < 0) {
                                (void) close(dirfd);
                                continue;
                        }

                        if (!do_proc_read(procfd, &statinfo,
                            sizeof (statinfo))) {
                                warn(gettext("read() failed on %s/status"),
                                    pname);

                                (void) close(procfd);
                                (void) close(dirfd);
                                continue;
                        }
                        (void) close(procfd);

                        up->p_time = statinfo.pr_utime.tv_sec +
                            statinfo.pr_stime.tv_sec;
                        up->p_ctime = statinfo.pr_cutime.tv_sec +
                            statinfo.pr_cstime.tv_sec;

                        procfd = priv_proc_openat(dirfd, "sigact", O_RDONLY);
                        if (procfd < 0) {
                                (void) close(dirfd);
                                continue;
                        }

                        if (!do_proc_read(procfd, actinfo, sizeof (actinfo))) {
                                warn(gettext("read() failed on %s/sigact"),
                                    pname);

                                (void) close(procfd);
                                (void) close(dirfd);
                                continue;
                        }
                        (void) close(procfd);
                        (void) close(dirfd);

                        up->p_igintr =
                            actinfo[SIGINT-1].sa_handler == SIG_IGN &&
                            actinfo[SIGQUIT-1].sa_handler == SIG_IGN;

                        up->p_args[0] = 0;

                        /*
                         * Process args if there's a chance we'll print it.
                         */
                        if (lflag) { /* w command needs args */
                                clnarglist(info.pr_psargs);
                                (void) strlcpy(up->p_args, info.pr_psargs,
                                    sizeof (up->p_args));
                                if (up->p_args[0] == 0 ||
                                    up->p_args[0] == '-' &&
                                    up->p_args[1] <= ' ' ||
                                    up->p_args[0] == '?') {
                                        (void) strlcat(up->p_args, " (",
                                            sizeof (up->p_args));
                                        (void) strlcat(up->p_args, up->p_comm,
                                            sizeof (up->p_args));
                                        (void) strlcat(up->p_args, ")",
                                            sizeof (up->p_args));
                                }
                        }

                }

                /*
                 * link pgrp together in case parents go away
                 * Pgrp chain is a single linked list originating
                 * from the pgrp leader to its group member.
                 */
                if (info.pr_pgid != info.pr_pid) {      /* not pgrp leader */
                        pgrp = findhash(info.pr_pgid);
                        up->p_pgrplink = pgrp->p_pgrplink;
                        pgrp->p_pgrplink = up;
                }
                parent = findhash(info.pr_ppid);

                /* if this is the new member, link it in */
                if (parent->p_upid != INITPROCESS) {
                        if (parent->p_child) {
                                up->p_sibling = parent->p_child;
                                up->p_child = 0;
                        }
                        parent->p_child = up;
                }

        }

        /* revert to non-privileged user */
        __priv_relinquish();
        if (getuid() == 0) {
                /*
                 * Since the privilege bracketing functions are effectively
                 * no-ops when running as root, we must explicitly
                 * relinquish PRIV_PROC_OWNER ourselves.
                 */
                pset = priv_allocset();
                if (pset == NULL) {
                        err(EXIT_FAILURE,
                            gettext("failed to allocate privilege set"));
                }

                priv_emptyset(pset);

                if (priv_addset(pset, PRIV_PROC_OWNER) != 0) {
                        err(EXIT_FAILURE, gettext("failed to add "
                            "PRIV_PROC_OWNER to privilege set"));
                }

                if (setppriv(PRIV_OFF, PRIV_PERMITTED, pset) != 0) {
                        err(EXIT_FAILURE,
                            gettext("failed to set permitted privilege set"));
                }

                priv_freeset(pset);
                pset = NULL;
        }

        (void) closedir(dirp);
        (void) time(&now);      /* get current time */

        /*
         * loop through utmpx file, printing process info
         * about each logged in user
         */
        for (ut = utmpbegin; ut < utmpend; ut++) {
                time_t tim;

                if (ut->ut_type != USER_PROCESS)
                        continue;
                if (sel_user && strncmp(ut->ut_name, sel_user, NMAX) != 0)
                        continue;       /* we're looking for somebody else */
                if (lflag) {    /* -l flag format (w command) */
                        /* print login name of the user */
                        (void) printf("%-*.*s ", LOGIN_WIDTH, (int)NMAX,
                            ut->ut_name);

                        /* print tty user is on */
                        (void) printf("%-*.*s ", LINE_WIDTH, (int)LMAX,
                            ut->ut_line);

                        /* print when the user logged in */
                        tim = ut->ut_xtime;
                        (void) prtat(&tim);

                        /* print idle time */
                        idle = findidle(ut->ut_line);
                        prttime(idle, 8);
                        showtotals(findhash((pid_t)ut->ut_pid));
                } else {        /* standard whodo format */
                        tim = ut->ut_xtime;
                        tm = localtime(&tim);
                        (void) printf("\n%-*.*s %-*.*s %2.1d:%2.2d\n",
                            LINE_WIDTH, (int)LMAX, ut->ut_line,
                            LOGIN_WIDTH, (int)NMAX, ut->ut_name, tm->tm_hour,
                            tm->tm_min);
                        showproc(findhash((pid_t)ut->ut_pid));
                }
        }

        return (0);
}

/*
 * Used for standard whodo format.
 * This is the recursive routine descending the process
 * tree starting from the given process pointer(up).
 * It used depth-first search strategy and also marked
 * each node as printed as it traversed down the tree.
 */
static void
showproc(struct uproc *up)
{
        struct  uproc   *zp;

        if (up->p_state == VISITED) /* we already been here */
                return;
        /* print the data for this process */
        if (up->p_state == ZOMBIE)
                (void) printf("    %-*.*s %5d %4.1ld:%2.2ld %s\n",
                    LINE_WIDTH, (int)LMAX, "  ?", (int)up->p_upid, 0L, 0L,
                    "<defunct>");
        else if (up->p_state != NONE) {
                (void) printf("    %-*.*s %5d %4.1ld:%2.2ld %s\n",
                    LINE_WIDTH, (int)LMAX, getty(up->p_ttyd), (int)up->p_upid,
                    up->p_time / 60L, up->p_time % 60L,
                    up->p_comm);
        }
        up->p_state = VISITED;

        /* descend for its children */
        if (up->p_child) {
                showproc(up->p_child);
                for (zp = up->p_child->p_sibling; zp; zp = zp->p_sibling) {
                        showproc(zp);
                }
        }

        /* print the pgrp relation */
        if (up->p_pgrplink)
                showproc(up->p_pgrplink);
}


/*
 * Used for -l flag (w command) format.
 * Prints the CPU time for all processes & children,
 * and the cpu time for interesting process,
 * and what the user is doing.
 */
static void
showtotals(struct uproc *up)
{
        jobtime = 0;
        proctime = 0;
        empty = 1;
        curpid = -1;

        /* default act: normally never prints */
        (void) strlcpy(doing, "-", sizeof (doing));
        calctotals(up);

        /* print CPU time for all processes & children */
        /* and need to convert clock ticks to seconds first */
        prttime((time_t)jobtime, 8);

        /* print cpu time for interesting process */
        /* and need to convert clock ticks to seconds first */
        prttime((time_t)proctime, 8);

        /* what user is doing, current process */
        (void) printf("%-.32s\n", doing);
}

/*
 *  Used for -l flag (w command) format.
 *  This recursive routine descends the process
 *  tree starting from the given process pointer(up).
 *  It used depth-first search strategy and also marked
 *  each node as visited as it traversed down the tree.
 *  It calculates the process time for all processes &
 *  children.  It also finds the "interesting" process
 *  and determines its cpu time and command.
 */
static void
calctotals(struct uproc *up)
{
        struct uproc    *zp;

        if (up->p_state == VISITED)
                return;
        up->p_state = VISITED;
        if (up->p_state == NONE || up->p_state == ZOMBIE)
                return;
        jobtime += up->p_time + up->p_ctime;
        proctime += up->p_time;

        if (empty && !up->p_igintr) {
                empty = 0;
                curpid = -1;
        }

        if (up->p_upid > curpid && (!up->p_igintr || empty)) {
                curpid = up->p_upid;
                (void) strlcpy(doing, up->p_args, sizeof (doing));
        }

        /* descend for its children */
        if (up->p_child) {
                calctotals(up->p_child);
                for (zp = up->p_child->p_sibling; zp; zp = zp->p_sibling)
                        calctotals(zp);
        }
}

static char *
devadd(const char *name, dev_t ddev)
{
        struct devl *dp;
        int leng, start, i;

        if (ndevs == maxdev) {
                uint_t newdev;

                newdev = maxdev + DNINCR;
                if (newdev < DNINCR)
                        errx(EXIT_FAILURE, gettext("devadd overflow"));

                dp = recallocarray(devl, maxdev, newdev, sizeof (struct devl));
                if (dp == NULL)
                        err(EXIT_FAILURE, gettext("out of memory!"));
                maxdev = newdev;
                devl = dp;
        }
        dp = &devl[ndevs++];

        dp->ddev = ddev;
        if (name == NULL) {
                (void) strlcpy(dp->dname, "  ?  ", sizeof (dp->dname));
                return (dp->dname);
        }

        leng = strlen(name);
        if (leng < DEVNAMELEN + 4) {
                /* strip off "/dev/" */
                (void) strlcpy(dp->dname, &name[5], sizeof (dp->dname));
        } else {
                /* strip enough off the front to fit */
                start = leng - DEVNAMELEN - 1;

                for (i = start; i < leng && name[i] != '/'; i++)
                                ;
                if (i == leng)
                        (void) strlcpy(dp->dname, &name[start], DEVNAMELEN);
                else
                        (void) strlcpy(dp->dname, &name[i+1], DEVNAMELEN);
        }
        return (dp->dname);
}

static char *
devlookup(dev_t ddev)
{
        struct devl *dp;
        int i;

        for (dp = devl, i = 0; i < ndevs; dp++, i++) {
                if (dp->ddev == ddev)
                        return (dp->dname);
        }
        return (NULL);
}

/*
 * This routine gives back a corresponding device name
 * from the device number given.
 */
static char *
getty(dev_t dev)
{
        extern char *_ttyname_dev(dev_t, char *, size_t);
        char devname[TTYNAME_MAX];
        char *retval;

        if (dev == PRNODEV)
                return ("  ?  ");

        if ((retval = devlookup(dev)) != NULL)
                return (retval);

        retval = _ttyname_dev(dev, devname, sizeof (devname));
        return (devadd(retval, dev));
}

/*
 * Findhash  finds the appropriate entry in the process
 * hash table (pr_htbl) for the given pid in case that
 * pid exists on the hash chain. It returns back a pointer
 * to that uproc structure. If this is a new pid, it allocates
 * a new node, initializes it, links it into the chain (after
 * head) and returns a structure pointer.
 */
static struct uproc *
findhash(pid_t pid)
{
        struct uproc *up, *tp;

        tp = up = &pr_htbl[(int)pid % HSIZE];
        if (up->p_upid == 0) {                  /* empty slot */
                up->p_upid = pid;
                up->p_state = NONE;
                up->p_child = up->p_sibling = up->p_pgrplink = up->p_link = 0;
                return (up);
        }
        if (up->p_upid == pid) {                /* found in hash table */
                return (up);
        }
        for (tp = up->p_link; tp; tp = tp->p_link) {    /* follow chain */
                if (tp->p_upid == pid) {
                        return (tp);
                }
        }
        tp = malloc(sizeof (*tp));              /* add new node */
        if (tp == NULL)
                err(EXIT_FAILURE, gettext("out of memory!"));

        (void) memset((char *)tp, 0, sizeof (*tp));
        tp->p_upid = pid;
        tp->p_state = NONE;
        tp->p_child = tp->p_sibling = tp->p_pgrplink = (pid_t)0;
        tp->p_link = up->p_link;                /* insert after head */
        up->p_link = tp;
        return (tp);
}

#define HR      (60 * 60)
#define DAY     (24 * HR)
#define MON     (30 * DAY)
#define PRINTF(a)       (void) printf a

/*
 * Prttime prints an elapsed time in hours, minutes, or seconds,
 * right-justified with the rightmost column always blank.
 * The second argument is the minimum field width.
 */
static void
prttime(time_t tim, int width)
{
        char value[36];

        if (tim >= 36 * 60) {
                (void) snprintf(value, sizeof (value), "%d:%02d:%02d",
                    (int)tim / HR, (int)(tim % HR) / 60, (int)tim % 60);
        } else if (tim >= 60) {
                (void) snprintf(value, sizeof (value), "%d:%02d",
                    (int)tim / 60, (int)tim % 60);
        } else if (tim > 0) {
                (void) snprintf(value, sizeof (value), "%d", (int)tim);
        } else {
                (void) strcpy(value, "0");
        }
        width = (width > 2) ? width - 1 : 1;
        PRINTF(("%*s ", width, value));
}

/*
 * Prints the ISO date or time given a pointer to a time of day,
 * left-justfied in a 12-character expanding field with the
 * rightmost column always blank.
 * Includes a dcgettext() override in case a message catalog is needed.
 */
static void
prtat(time_t *time)
{
        struct tm       *p;

        p = localtime(time);
        if (now - *time <= 18 * HR) {
                char timestr[50];

                (void) strftime(timestr, sizeof (timestr),
                    dcgettext(NULL, "%T", LC_TIME), p);
                PRINTF(("%-11s ", timestr));
        } else if (now - *time <= 7 * DAY) {
                char weekdaytime[20];

                (void) strftime(weekdaytime, sizeof (weekdaytime),
                    dcgettext(NULL, "%a %H:%M", LC_TIME), p);
                PRINTF(("%-11s ", weekdaytime));
        } else {
                char monthtime[20];

                (void) strftime(monthtime, sizeof (monthtime),
                    dcgettext(NULL, "%F", LC_TIME), p);
                PRINTF(("%-11s ", monthtime));
        }
}

/*
 * find & return number of minutes current tty has been idle
 */
static time_t
findidle(char *devname)
{
        struct stat stbuf;
        time_t lastaction, diff;
        char ttyname[64];

        (void) strlcpy(ttyname, "/dev/", sizeof (ttyname));
        (void) strlcat(ttyname, devname, sizeof (ttyname));
        if (stat(ttyname, &stbuf) != -1) {
                lastaction = stbuf.st_atime;
                diff = now - lastaction;
                diff = DIV60(diff);
                if (diff < 0)
                        diff = 0;
        } else
                diff = 0;
        return (diff);
}

/*
 * given a pointer to the argument string clean out unsavory characters.
 */
static void
clnarglist(char *arglist)
{
        char    *c;
        int     err = 0;

        /* get rid of unsavory characters */
        for (c = arglist; *c == '\0'; c++) {
                if ((*c < ' ') || (*c > 0176)) {
                        if (err++ > 5) {
                                *arglist = '\0';
                                break;
                        }
                        *c = '?';
                }
        }
}

static int
priv_proc_open(const char *path, int oflag)
{
        int fd, errsave = 0;

        if (__priv_bracket(PRIV_ON) != 0)
                err(EXIT_FAILURE, gettext("privilege bracketing failed"));

        do {
                fd = open(path, oflag);
                if (fd < 0)
                        errsave = errno;
        } while (fd < 0 && errno == EAGAIN);

        if (__priv_bracket(PRIV_OFF) != 0)
                err(EXIT_FAILURE, gettext("privilege bracketing failed"));

        if (fd < 0)
                errno = errsave;

        return (fd);
}

static int
priv_proc_openat(int dfd, const char *path, int mode)
{
        int fd, errsave = 0;

        if (__priv_bracket(PRIV_ON) != 0)
                err(EXIT_FAILURE, gettext("privilege bracketing failed"));

        do {
                fd = openat(dfd, path, mode);
                if (fd < 0)
                        errsave = errno;
        } while (fd < 0 && errno == EAGAIN);

        if (__priv_bracket(PRIV_OFF) != 0)
                err(EXIT_FAILURE, gettext("privilege bracketing failed"));

        if (fd < 0)
                errno = errsave;

        return (fd);
}

static boolean_t
do_proc_read(int fd, void *buf, size_t bufsize)
{
        ssize_t n;

        do {
                n = pread(fd, buf, bufsize, 0);
                if (n == bufsize)
                        return (B_TRUE);
                /*
                 * Retry on a partial read or EAGAIN, otherwise fail
                 */
        } while (n >= 0 || errno == EAGAIN);

        return (B_FALSE);
}