root/bin/pkill/pkill.c
/*      $NetBSD: pkill.c,v 1.16 2005/10/10 22:13:20 kleink Exp $        */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2002 The NetBSD Foundation, Inc.
 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Doran.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/user.h>

#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <paths.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <regex.h>
#include <ctype.h>
#include <fcntl.h>
#include <kvm.h>
#include <err.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#include <locale.h>
#include <jail.h>

#define STATUS_MATCH    0
#define STATUS_NOMATCH  1
#define STATUS_BADUSAGE 2
#define STATUS_ERROR    3

#define MIN_PID 5
#define MAX_PID 99999

/* Ignore system-processes (if '-S' flag is not specified) and myself. */
#define PSKIP(kp)       ((kp)->ki_pid == mypid ||                       \
                         (!kthreads && ((kp)->ki_flag & P_KPROC) != 0))

enum listtype {
        LT_GENERIC,
        LT_USER,
        LT_GROUP,
        LT_TTY,
        LT_PGRP,
        LT_JAIL,
        LT_SID,
        LT_CLASS
};

struct list {
        SLIST_ENTRY(list) li_chain;
        long    li_number;
        char    *li_name;
};

SLIST_HEAD(listhead, list);

static struct kinfo_proc *plist;
static char     *selected;
static const char *delim = "\n";
static int      nproc;
static int      pgrep;
static int      signum = SIGTERM;
static int      newest;
static int      oldest;
static int      interactive;
static int      inverse;
static int      longfmt;
static int      matchargs;
static int      fullmatch;
static int      kthreads;
static int      cflags = REG_EXTENDED;
static int      quiet;
static kvm_t    *kd;
static pid_t    mypid;

static struct listhead euidlist = SLIST_HEAD_INITIALIZER(euidlist);
static struct listhead ruidlist = SLIST_HEAD_INITIALIZER(ruidlist);
static struct listhead rgidlist = SLIST_HEAD_INITIALIZER(rgidlist);
static struct listhead pgrplist = SLIST_HEAD_INITIALIZER(pgrplist);
static struct listhead ppidlist = SLIST_HEAD_INITIALIZER(ppidlist);
static struct listhead tdevlist = SLIST_HEAD_INITIALIZER(tdevlist);
static struct listhead sidlist = SLIST_HEAD_INITIALIZER(sidlist);
static struct listhead jidlist = SLIST_HEAD_INITIALIZER(jidlist);
static struct listhead classlist = SLIST_HEAD_INITIALIZER(classlist);

static void     usage(void) __attribute__((__noreturn__));
static int      killact(const struct kinfo_proc *);
static int      grepact(const struct kinfo_proc *);
static void     makelist(struct listhead *, enum listtype, char *);
static int      takepid(const char *, int);

int
main(int argc, char **argv)
{
        char *buf, *mstr, **pargv, *p, *q, *pidfile;
        const char *execf, *coref;
        size_t bufsz;
        int ancestors, debug_opt, did_action;
        int i, ch, bestidx, rv, criteria, pidfromfile, pidfilelock;
        size_t jsz;
        int (*action)(const struct kinfo_proc *);
        struct kinfo_proc *kp;
        struct list *li;
        struct timeval best_tval;
        regex_t reg;
        regmatch_t regmatch;
        pid_t pid;

        setlocale(LC_ALL, "");

        if (strcmp(getprogname(), "pgrep") == 0) {
                action = grepact;
                pgrep = 1;
        } else {
                action = killact;
                p = argv[1];

                if (argc > 1 && p[0] == '-') {
                        p++;
                        i = (int)strtol(p, &q, 10);
                        if (*q == '\0') {
                                signum = i;
                                argv++;
                                argc--;
                        } else {
                                if (strncasecmp(p, "SIG", 3) == 0)
                                        p += 3;
                                for (i = 1; i < NSIG; i++)
                                        if (strcasecmp(sys_signame[i], p) == 0)
                                                break;
                                if (i != NSIG) {
                                        signum = i;
                                        argv++;
                                        argc--;
                                }
                        }
                }
        }

        buf = NULL;
        ancestors = 0;
        criteria = 0;
        debug_opt = 0;
        pidfile = NULL;
        pidfilelock = 0;
        quiet = 0;
        execf = NULL;
        coref = _PATH_DEVNULL;

        while ((ch = getopt(argc, argv, "DF:G:ILM:N:P:SU:ac:d:fg:ij:lnoqs:t:u:vx")) != -1)
                switch (ch) {
                case 'D':
                        debug_opt++;
                        break;
                case 'F':
                        pidfile = optarg;
                        criteria = 1;
                        break;
                case 'G':
                        makelist(&rgidlist, LT_GROUP, optarg);
                        criteria = 1;
                        break;
                case 'I':
                        if (pgrep)
                                usage();
                        interactive = 1;
                        break;
                case 'L':
                        pidfilelock = 1;
                        break;
                case 'M':
                        coref = optarg;
                        break;
                case 'N':
                        execf = optarg;
                        break;
                case 'P':
                        makelist(&ppidlist, LT_GENERIC, optarg);
                        criteria = 1;
                        break;
                case 'S':
                        if (!pgrep)
                                usage();
                        kthreads = 1;
                        break;
                case 'U':
                        makelist(&ruidlist, LT_USER, optarg);
                        criteria = 1;
                        break;
                case 'a':
                        ancestors++;
                        break;
                case 'c':
                        makelist(&classlist, LT_CLASS, optarg);
                        criteria = 1;
                        break;
                case 'd':
                        if (!pgrep)
                                usage();
                        delim = optarg;
                        break;
                case 'f':
                        matchargs = 1;
                        break;
                case 'g':
                        makelist(&pgrplist, LT_PGRP, optarg);
                        criteria = 1;
                        break;
                case 'i':
                        cflags |= REG_ICASE;
                        break;
                case 'j':
                        makelist(&jidlist, LT_JAIL, optarg);
                        criteria = 1;
                        break;
                case 'l':
                        longfmt = 1;
                        break;
                case 'n':
                        newest = 1;
                        criteria = 1;
                        break;
                case 'o':
                        oldest = 1;
                        criteria = 1;
                        break;
                case 'q':
                        if (!pgrep)
                                usage();
                        quiet = 1;
                        break;
                case 's':
                        makelist(&sidlist, LT_SID, optarg);
                        criteria = 1;
                        break;
                case 't':
                        makelist(&tdevlist, LT_TTY, optarg);
                        criteria = 1;
                        break;
                case 'u':
                        makelist(&euidlist, LT_USER, optarg);
                        criteria = 1;
                        break;
                case 'v':
                        inverse = 1;
                        break;
                case 'x':
                        fullmatch = 1;
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }

        argc -= optind;
        argv += optind;
        if (argc != 0)
                criteria = 1;
        if (!criteria)
                usage();
        if (newest && oldest)
                errx(STATUS_ERROR, "Options -n and -o are mutually exclusive");
        if (pidfile != NULL)
                pidfromfile = takepid(pidfile, pidfilelock);
        else {
                if (pidfilelock) {
                        errx(STATUS_ERROR,
                            "Option -L doesn't make sense without -F");
                }
                pidfromfile = -1;
        }

        mypid = getpid();

        /*
         * If we're not matching args, we only need a buffer large enough to
         * hold some relatively short error strings.  Otherwise, we have to
         * assume we'll need up to ARG_MAX bytes for arguments.
         */
        bufsz = _POSIX2_LINE_MAX;
        if (matchargs) {
                long arg_max;

                arg_max = sysconf(_SC_ARG_MAX);
                if (arg_max == -1)
                        arg_max = ARG_MAX;

                /*
                 * The absolute worst case scenario is ARG_MAX single-byte
                 * arguments which we'll then separate with spaces and NUL
                 * terminate.
                 */
                bufsz = (arg_max * 2) + 1;
        }

        buf = malloc(bufsz);
        if (buf == NULL)
                err(STATUS_ERROR, "malloc");

        /*
         * Retrieve the list of running processes from the kernel.
         */
        kd = kvm_openfiles(execf, coref, NULL, O_RDONLY, buf);
        if (kd == NULL)
                errx(STATUS_ERROR, "Cannot open kernel files (%s)", buf);

        /*
         * Use KERN_PROC_PROC instead of KERN_PROC_ALL, since we
         * just want processes and not individual kernel threads.
         */
        if (pidfromfile >= 0)
                plist = kvm_getprocs(kd, KERN_PROC_PID, pidfromfile, &nproc);
        else
                plist = kvm_getprocs(kd, KERN_PROC_PROC, 0, &nproc);
        if (plist == NULL) {
                errx(STATUS_ERROR, "Cannot get process list (%s)",
                    kvm_geterr(kd));
        }

        /*
         * Allocate memory which will be used to keep track of the
         * selection.
         */
        if ((selected = malloc(nproc)) == NULL) {
                err(STATUS_ERROR, "Cannot allocate memory for %d processes",
                    nproc);
        }
        memset(selected, 0, nproc);

        /*
         * Refine the selection.
         */
        for (; *argv != NULL; argv++) {
                if ((rv = regcomp(&reg, *argv, cflags)) != 0) {
                        regerror(rv, &reg, buf, bufsz);
                        errx(STATUS_BADUSAGE,
                            "Cannot compile regular expression `%s' (%s)",
                            *argv, buf);
                }

                for (i = 0, kp = plist; i < nproc; i++, kp++) {
                        if (PSKIP(kp)) {
                                if (debug_opt > 0)
                                    fprintf(stderr, "* Skipped %5d %3d %s\n",
                                        kp->ki_pid, kp->ki_uid, kp->ki_comm);
                                continue;
                        }

                        if (matchargs &&
                            (pargv = kvm_getargv(kd, kp, 0)) != NULL) {
                                jsz = 0;
                                while (jsz < bufsz && *pargv != NULL) {
                                        jsz += snprintf(buf + jsz,
                                            bufsz - jsz,
                                            pargv[1] != NULL ? "%s " : "%s",
                                            pargv[0]);
                                        pargv++;
                                }
                                mstr = buf;
                        } else
                                mstr = kp->ki_comm;

                        rv = regexec(&reg, mstr, 1, &regmatch, 0);
                        if (rv == 0) {
                                if (fullmatch) {
                                        if (regmatch.rm_so == 0 &&
                                            regmatch.rm_eo ==
                                            (off_t)strlen(mstr))
                                                selected[i] = 1;
                                } else
                                        selected[i] = 1;
                        } else if (rv != REG_NOMATCH) {
                                regerror(rv, &reg, buf, bufsz);
                                errx(STATUS_ERROR,
                                    "Regular expression evaluation error (%s)",
                                    buf);
                        }
                        if (debug_opt > 1) {
                                const char *rv_res = "NoMatch";
                                if (selected[i])
                                        rv_res = "Matched";
                                fprintf(stderr, "* %s %5d %3d %s\n", rv_res,
                                    kp->ki_pid, kp->ki_uid, mstr);
                        }
                }

                regfree(&reg);
        }

        for (i = 0, kp = plist; i < nproc; i++, kp++) {
                if (PSKIP(kp))
                        continue;

                if (pidfromfile >= 0 && kp->ki_pid != pidfromfile) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &ruidlist, li_chain)
                        if (kp->ki_ruid == (uid_t)li->li_number)
                                break;
                if (SLIST_FIRST(&ruidlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &rgidlist, li_chain)
                        if (kp->ki_rgid == (gid_t)li->li_number)
                                break;
                if (SLIST_FIRST(&rgidlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &euidlist, li_chain)
                        if (kp->ki_uid == (uid_t)li->li_number)
                                break;
                if (SLIST_FIRST(&euidlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &ppidlist, li_chain)
                        if (kp->ki_ppid == (pid_t)li->li_number)
                                break;
                if (SLIST_FIRST(&ppidlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &pgrplist, li_chain)
                        if (kp->ki_pgid == (pid_t)li->li_number)
                                break;
                if (SLIST_FIRST(&pgrplist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &tdevlist, li_chain) {
                        if (li->li_number == -1 &&
                            (kp->ki_flag & P_CONTROLT) == 0)
                                break;
                        if (kp->ki_tdev == (dev_t)li->li_number)
                                break;
                }
                if (SLIST_FIRST(&tdevlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &sidlist, li_chain)
                        if (kp->ki_sid == (pid_t)li->li_number)
                                break;
                if (SLIST_FIRST(&sidlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &jidlist, li_chain) {
                        /* A particular jail ID, including 0 (not in jail) */
                        if (kp->ki_jid == (int)li->li_number)
                                break;
                        /* Any jail */
                        if (kp->ki_jid > 0 && li->li_number == -1)
                                break;
                }
                if (SLIST_FIRST(&jidlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                SLIST_FOREACH(li, &classlist, li_chain) {
                        /*
                         * We skip P_SYSTEM processes to match ps(1) output.
                         */
                        if ((kp->ki_flag & P_SYSTEM) == 0 &&
                            strcmp(kp->ki_loginclass, li->li_name) == 0)
                                break;
                }
                if (SLIST_FIRST(&classlist) != NULL && li == NULL) {
                        selected[i] = 0;
                        continue;
                }

                if (argc == 0)
                        selected[i] = 1;
        }

        if (!ancestors) {
                pid = mypid;
                while (pid) {
                        for (i = 0, kp = plist; i < nproc; i++, kp++) {
                                if (PSKIP(kp))
                                        continue;
                                if (kp->ki_pid == pid) {
                                        selected[i] = 0;
                                        pid = kp->ki_ppid;
                                        break;
                                }
                        }
                        if (i == nproc) {
                                if (pid == mypid)
                                        pid = getppid();
                                else
                                        break;  /* Maybe we're in a jail ? */
                        }
                }
        }

        if (newest || oldest) {
                best_tval.tv_sec = 0;
                best_tval.tv_usec = 0;
                bestidx = -1;

                for (i = 0, kp = plist; i < nproc; i++, kp++) {
                        if (!selected[i])
                                continue;
                        if (bestidx == -1) {
                                /* The first entry of the list which matched. */
                                ;
                        } else if (timercmp(&kp->ki_start, &best_tval, >)) {
                                /* This entry is newer than previous "best". */
                                if (oldest)     /* but we want the oldest */
                                        continue;
                        } else {
                                /* This entry is older than previous "best". */
                                if (newest)     /* but we want the newest */
                                        continue;
                        }
                        /* This entry is better than previous "best" entry. */
                        best_tval.tv_sec = kp->ki_start.tv_sec;
                        best_tval.tv_usec = kp->ki_start.tv_usec;
                        bestidx = i;
                }

                memset(selected, 0, nproc);
                if (bestidx != -1)
                        selected[bestidx] = 1;
        }

        /*
         * Take the appropriate action for each matched process, if any.
         */
        did_action = 0;
        for (i = 0, rv = 0, kp = plist; i < nproc; i++, kp++) {
                if (PSKIP(kp))
                        continue;
                if (selected[i]) {
                        if (longfmt && !pgrep) {
                                did_action = 1;
                                printf("kill -%d %d\n", signum, kp->ki_pid);
                        }
                        if (inverse)
                                continue;
                } else if (!inverse)
                        continue;
                rv |= (*action)(kp);
        }
        if (rv && pgrep && !quiet)
                putchar('\n');
        if (!did_action && !pgrep && longfmt)
                fprintf(stderr,
                    "No matching processes belonging to you were found\n");

        free(buf);
        exit(rv ? STATUS_MATCH : STATUS_NOMATCH);
}

static void
usage(void)
{
        const char *ustr;

        if (pgrep)
                ustr = "[-LSfilnoqvx] [-d delim]";
        else
                ustr = "[-signal] [-ILfilnovx]";

        fprintf(stderr,
                "usage: %s %s [-F pidfile] [-G gid] [-M core] [-N system]\n"
                "             [-P ppid] [-U uid] [-c class] [-g pgrp] [-j jail]\n"
                "             [-s sid] [-t tty] [-u euid] pattern ...\n",
                getprogname(), ustr);

        exit(STATUS_BADUSAGE);
}

static void
show_process(const struct kinfo_proc *kp)
{
        char **argv;

        if (quiet) {
                assert(pgrep);
                return;
        }
        if ((longfmt || !pgrep) && matchargs &&
            (argv = kvm_getargv(kd, kp, 0)) != NULL) {
                printf("%d ", (int)kp->ki_pid);
                for (; *argv != NULL; argv++) {
                        printf("%s", *argv);
                        if (argv[1] != NULL)
                                putchar(' ');
                }
        } else if (longfmt || !pgrep)
                printf("%d %s", (int)kp->ki_pid, kp->ki_comm);
        else
                printf("%d", (int)kp->ki_pid);
}

static int
killact(const struct kinfo_proc *kp)
{
        int ch, first;

        if (interactive) {
                /*
                 * Be careful, ask before killing.
                 */
                printf("kill ");
                show_process(kp);
                printf("? ");
                fflush(stdout);
                first = ch = getchar();
                while (ch != '\n' && ch != EOF)
                        ch = getchar();
                if (first != 'y' && first != 'Y')
                        return (1);
        }
        if (kill(kp->ki_pid, signum) == -1) {
                /* 
                 * Check for ESRCH, which indicates that the process
                 * disappeared between us matching it and us
                 * signalling it; don't issue a warning about it.
                 */
                if (errno != ESRCH)
                        warn("signalling pid %d", (int)kp->ki_pid);
                /*
                 * Return 0 to indicate that the process should not be
                 * considered a match, since we didn't actually get to
                 * signal it.
                 */
                return (0);
        }
        return (1);
}

static int
grepact(const struct kinfo_proc *kp)
{
        static bool first = true;

        if (!quiet && !first)
                printf("%s", delim);
        show_process(kp);
        first = false;
        return (1);
}

static void
makelist(struct listhead *head, enum listtype type, char *src)
{
        struct list *li;
        struct passwd *pw;
        struct group *gr;
        struct stat st;
        const char *cp;
        char *sp, *ep, buf[MAXPATHLEN];
        int empty;

        empty = 1;

        while ((sp = strsep(&src, ",")) != NULL) {
                if (*sp == '\0')
                        usage();

                if ((li = malloc(sizeof(*li))) == NULL) {
                        err(STATUS_ERROR, "Cannot allocate %zu bytes",
                            sizeof(*li));
                }

                SLIST_INSERT_HEAD(head, li, li_chain);
                empty = 0;

                if (type != LT_CLASS)
                        li->li_number = (uid_t)strtol(sp, &ep, 0);

                if (type != LT_CLASS && *ep == '\0') {
                        switch (type) {
                        case LT_PGRP:
                                if (li->li_number == 0)
                                        li->li_number = getpgrp();
                                break;
                        case LT_SID:
                                if (li->li_number == 0)
                                        li->li_number = getsid(mypid);
                                break;
                        case LT_JAIL:
                                if (li->li_number < 0)
                                        errx(STATUS_BADUSAGE,
                                             "Negative jail ID `%s'", sp);
                                /* For compatibility with old -j */
                                if (li->li_number == 0)
                                        li->li_number = -1;     /* any jail */
                                break;
                        case LT_TTY:
                                if (li->li_number < 0)
                                        errx(STATUS_BADUSAGE,
                                             "Negative /dev/pts tty `%s'", sp);
                                snprintf(buf, sizeof(buf), _PATH_DEV "pts/%s",
                                    sp);
                                if (stat(buf, &st) != -1)
                                        goto foundtty;
                                if (errno == ENOENT)
                                        errx(STATUS_BADUSAGE, "No such tty: `"
                                            _PATH_DEV "pts/%s'", sp);
                                err(STATUS_ERROR, "Cannot access `"
                                    _PATH_DEV "pts/%s'", sp);
                                break;
                        default:
                                break;
                        }
                        continue;
                }

                switch (type) {
                case LT_USER:
                        if ((pw = getpwnam(sp)) == NULL)
                                errx(STATUS_BADUSAGE, "Unknown user `%s'", sp);
                        li->li_number = pw->pw_uid;
                        break;
                case LT_GROUP:
                        if ((gr = getgrnam(sp)) == NULL)
                                errx(STATUS_BADUSAGE, "Unknown group `%s'", sp);
                        li->li_number = gr->gr_gid;
                        break;
                case LT_TTY:
                        if (strcmp(sp, "-") == 0) {
                                li->li_number = -1;
                                break;
                        } else if (strcmp(sp, "co") == 0) {
                                cp = "console";
                        } else {
                                cp = sp;
                        }

                        snprintf(buf, sizeof(buf), _PATH_DEV "%s", cp);
                        if (stat(buf, &st) != -1)
                                goto foundtty;

                        snprintf(buf, sizeof(buf), _PATH_DEV "tty%s", cp);
                        if (stat(buf, &st) != -1)
                                goto foundtty;

                        if (errno == ENOENT)
                                errx(STATUS_BADUSAGE, "No such tty: `%s'", sp);
                        err(STATUS_ERROR, "Cannot access `%s'", sp);

foundtty:               if ((st.st_mode & S_IFCHR) == 0)
                                errx(STATUS_BADUSAGE, "Not a tty: `%s'", sp);

                        li->li_number = st.st_rdev;
                        break;
                case LT_JAIL: {
                        int jid;

                        if (strcmp(sp, "none") == 0)
                                li->li_number = 0;
                        else if (strcmp(sp, "any") == 0)
                                li->li_number = -1;
                        else if ((jid = jail_getid(sp)) != -1)
                                li->li_number = jid;
                        else if (*ep != '\0')
                                errx(STATUS_BADUSAGE,
                                     "Invalid jail ID or name `%s'", sp);
                        break;
                }
                case LT_CLASS:
                        li->li_number = -1;
                        li->li_name = strdup(sp);
                        if (li->li_name == NULL)
                                err(STATUS_ERROR, "Cannot allocate memory");
                        break;
                default:
                        usage();
                }
        }

        if (empty)
                usage();
}

static int
takepid(const char *pidfile, int pidfilelock)
{
        char *endp, line[BUFSIZ];
        FILE *fh;
        long rval;

        fh = fopen(pidfile, "r");
        if (fh == NULL)
                err(STATUS_ERROR, "Cannot open pidfile `%s'", pidfile);

        if (pidfilelock) {
                /*
                 * If we can lock pidfile, this means that daemon is not
                 * running, so would be better not to kill some random process.
                 */
                if (flock(fileno(fh), LOCK_EX | LOCK_NB) == 0) {
                        (void)fclose(fh);
                        errx(STATUS_ERROR, "File '%s' can be locked", pidfile);
                } else {
                        if (errno != EWOULDBLOCK) {
                                errx(STATUS_ERROR,
                                    "Error while locking file '%s'", pidfile);
                        }
                }
        }

        if (fgets(line, sizeof(line), fh) == NULL) {
                if (feof(fh)) {
                        (void)fclose(fh);
                        errx(STATUS_ERROR, "Pidfile `%s' is empty", pidfile);
                }
                (void)fclose(fh);
                err(STATUS_ERROR, "Cannot read from pid file `%s'", pidfile);
        }
        (void)fclose(fh);

        rval = strtol(line, &endp, 10);
        if (*endp != '\0' && !isspace((unsigned char)*endp))
                errx(STATUS_ERROR, "Invalid pid in file `%s'", pidfile);
        else if (rval < MIN_PID || rval > MAX_PID)
                errx(STATUS_ERROR, "Invalid pid in file `%s'", pidfile);
        return (rval);
}