/*      $OpenBSD: lpc.c,v 1.20 2016/03/16 15:41:11 krw Exp $    */
/*      $NetBSD: lpc.c,v 1.11 2001/11/14 03:01:15 enami Exp $   */

/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 *
 * 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.
 */

#include <dirent.h>
#include <signal.h>
#include <syslog.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <ctype.h>
#include <string.h>
#include <grp.h>

#include "lp.h"
#include "lpc.h"
#include "extern.h"

#ifndef LPR_OPER
#define LPR_OPER        "operator"      /* group name of lpr operators */
#endif

/*
 * lpc -- line printer control program
 */

#define MAX_CMDLINE     200
#define MAX_MARGV       20
int     fromatty;

char    cmdline[MAX_CMDLINE];
int     margc;
char    *margv[MAX_MARGV];

static void              cmdscanner(void);
static struct cmd       *getcmd(char *);
static void              intr(int);
static void              makeargv(void);
static int               ingroup(char *);

int
main(int argc, char **argv)
{
        struct cmd *c;

        effective_uid = geteuid();
        real_uid = getuid();
        effective_gid = getegid();
        real_gid = getgid();
        PRIV_END;       /* be safe */

        openlog("lpc", 0, LOG_LPR);
        if (--argc > 0) {
                c = getcmd(*++argv);
                if (c == (struct cmd *)-1) {
                        printf("?Ambiguous command\n");
                        exit(1);
                }
                if (c == 0) {
                        printf("?Invalid command\n");
                        exit(1);
                }
                if (c->c_priv && real_uid && ingroup(LPR_OPER) == 0) {
                        printf("?Privileged command\n");
                        exit(1);
                }
                (*c->c_handler)(argc, argv);
                exit(0);
        }
        fromatty = isatty(fileno(stdin));
        signal(SIGINT, intr);
        for (;;)
                cmdscanner();
}

volatile sig_atomic_t gotintr;

static void
intr(int signo)
{
        if (!fromatty)
                _exit(0);
        gotintr = 1;
}

/*
 * Command parser.
 */
static void
cmdscanner(void)
{
        struct cmd *c;

        for (;;) {
                if (gotintr) {
                        putchar('\n');
                        gotintr = 0;
                }
                if (fromatty) {
                        printf("lpc> ");
                        fflush(stdout);
                }

                siginterrupt(SIGINT, 1);
                if (fgets(cmdline, MAX_CMDLINE, stdin) == NULL) {
                        if (errno == EINTR && gotintr) {
                                siginterrupt(SIGINT, 0);
                                return;
                        }
                        siginterrupt(SIGINT, 0);
                        quit(0, NULL);
                }
                siginterrupt(SIGINT, 0);

                makeargv();
                if (margc == 0)
                        break;
                c = getcmd(margv[0]);
                if (c == (struct cmd *)-1) {
                        printf("?Ambiguous command\n");
                        continue;
                }
                if (c == 0) {
                        printf("?Invalid command\n");
                        continue;
                }
                if (c->c_priv && getuid() && ingroup(LPR_OPER) == 0) {
                        printf("?Privileged command\n");
                        continue;
                }
                (*c->c_handler)(margc, margv);
        }
}

static struct cmd *
getcmd(char *name)
{
        char *p, *q;
        struct cmd *c, *found;
        int nmatches, longest;

        longest = 0;
        nmatches = 0;
        found = 0;
        for (c = cmdtab; (p = c->c_name) != NULL; c++) {
                for (q = name; *q == *p++; q++)
                        if (*q == 0)            /* exact match? */
                                return(c);
                if (!*q) {                      /* the name was a prefix */
                        if (q - name > longest) {
                                longest = q - name;
                                nmatches = 1;
                                found = c;
                        } else if (q - name == longest)
                                nmatches++;
                }
        }
        if (nmatches > 1)
                return((struct cmd *)-1);
        return(found);
}

/*
 * Slice a string up into argc/argv.
 */
static void
makeargv(void)
{
        char *cp = cmdline;
        char **ap = margv;

        margc = 0;
        while (margc < MAX_MARGV - 1 && (*ap = strsep(&cp, " \t\n")) != NULL) {
                if (**ap != '\0') {
                        ap++;
                        margc++;
                }
        }
        *ap = NULL;
}

#define HELPINDENT ((int)sizeof("directory"))

/*
 * Help command.
 */
void
help(int argc, char **argv)
{
        struct cmd *c;

        if (argc == 1) {
                int i, j, w;
                int columns, width = 0, lines;

                printf("Commands may be abbreviated.  Commands are:\n\n");
                for (c = cmdtab; c->c_name; c++) {
                        int len = strlen(c->c_name);

                        if (len > width)
                                width = len;
                }
                width = (width + 8) &~ 7;
                columns = 80 / width;
                if (columns == 0)
                        columns = 1;
                lines = (NCMDS + columns - 1) / columns;
                for (i = 0; i < lines; i++) {
                        for (j = 0; j < columns; j++) {
                                c = cmdtab + j * lines + i;
                                if (c->c_name)
                                        printf("%s", c->c_name);
                                if (c + lines >= &cmdtab[NCMDS]) {
                                        printf("\n");
                                        break;
                                }
                                w = strlen(c->c_name);
                                while (w < width) {
                                        w = (w + 8) &~ 7;
                                        putchar('\t');
                                }
                        }
                }
                return;
        }
        while (--argc > 0) {
                char *arg;

                arg = *++argv;
                c = getcmd(arg);
                if (c == (struct cmd *)-1)
                        printf("?Ambiguous help command %s\n", arg);
                else if (c == NULL)
                        printf("?Invalid help command %s\n", arg);
                else
                        printf("%-*s\t%s\n", HELPINDENT,
                                c->c_name, c->c_help);
        }
}

/*
 * return non-zero if the user is a member of the given group
 */
static int
ingroup(char *grname)
{
        static struct group *gptr = NULL;
        static gid_t groups[NGROUPS_MAX];
        static int ngroups;
        gid_t gid;
        int i;

        if (gptr == NULL) {
                if ((gptr = getgrnam(grname)) == NULL) {
                        warnx("Warning: unknown group `%s'", grname);
                        return(0);
                }
                if ((ngroups = getgroups(NGROUPS_MAX, groups)) < 0)
                        err(1, "getgroups");
        }
        gid = gptr->gr_gid;
        for (i = 0; i < ngroups; i++)
                if (gid == groups[i])
                        return(1);
        return(0);
}