NetBSD/usr.sbin/lpr/lpc/lpc.c

/*	$NetBSD: lpc.c,v 1.27 2017/05/04 16:26:09 sevan 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 <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1983, 1993\
 The Regents of the University of California.  All rights reserved.");
#if 0
static char sccsid[] = "@(#)lpc.c	8.3 (Berkeley) 4/28/95";
#else
__RCSID("$NetBSD: lpc.c,v 1.27 2017/05/04 16:26:09 sevan Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>

#include <dirent.h>
#include <signal.h>
#include <setjmp.h>
#include <syslog.h>
#include <histedit.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <grp.h>
#include <err.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_MARGV	20
int	fromatty;

char	*cmdline;
int	margc;
char	*margv[MAX_MARGV];
int	top;
uid_t	uid, euid;

jmp_buf	toplevel;

History	*hist;
HistEvent he;
EditLine *elptr;

__dead static void	 cmdscanner(int);
static struct cmd	*getcmd(const char *);
__dead static void	 intr(int);
static void		 makeargv(void);
static int		 ingroup(const char *);
const char		*prompt(void);
static int		 parse(char *, char *p[], int);

int
main(int argc, char *argv[])
{
	euid = geteuid();
	uid = getuid();
	seteuid(uid);
	setprogname(argv[0]);
	openlog("lpd", 0, LOG_LPR);

	if (--argc > 0) {
		argv++;
		exit(!parse(*argv, argv, argc));
	}
	fromatty = isatty(fileno(stdin));
	top = setjmp(toplevel) == 0;
	if (top)
		signal(SIGINT, intr);
	for (;;) {
		cmdscanner(top);
		top = 1;
	}
}

static int
parse(char *arg, char **pargv, int pargc)
{
	struct cmd *c;

	c = getcmd(arg);
	if (c == (struct cmd *)-1) {
		printf("?Ambiguous command\n");
		return(0);
	}
	if (c == 0) {
		printf("?Invalid command\n");
		return(0);
	}
	if (c->c_priv && getuid() && ingroup(LPR_OPER) == 0) {
		printf("?Privileged command\n");
		return(0);
	}
	(*c->c_handler)(pargc, pargv);
	return(1);
}

static void
intr(int signo)
{
	el_end(elptr);
	history_end(hist);
	if (!fromatty)
		exit(0);
	longjmp(toplevel, 1);
}

const char *
prompt(void)
{
	return ("lpc> ");
}

/*
 * Command parser.
 */
static void
cmdscanner(int tp)
{
	int scratch;
	const char *elline;

	if (!tp)
		putchar('\n');
	hist = history_init();
	history(hist, &he, H_SETSIZE, 100);	/* 100 elt history buffer */

	elptr = el_init(getprogname(), stdin, stdout, stderr);
	el_set(elptr, EL_EDITOR, "emacs");
	el_set(elptr, EL_PROMPT, prompt);
	el_set(elptr, EL_HIST, history, hist);
	el_source(elptr, NULL);

	for (;;) {
		cmdline = NULL;
		do {
			if (((elline = el_gets(elptr, &scratch)) != NULL)
			    && (scratch != 0)) {
				history(hist, &he, H_ENTER, elline);
				cmdline = strdup(elline);
				makeargv();
			} else {
				margc = 0;
				break;
			}
		} while (margc == 0);
		if (margc == 0)
			quit(0, NULL);
		if (!parse(cmdline, margv, margc)) {
			if (cmdline != NULL)
				free(cmdline);
			continue;
		}
		fflush(stdout);
		if (cmdline != NULL)
			free(cmdline);
	}
	longjmp(toplevel, 0);
}

static struct cmd *
getcmd(const char *name)
{
	const 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;
	char **argp = margv;
	int n = 0;
	size_t s;

	s = strlen(cmdline) + 1;
	margc = 0;
	for (cp = cmdline; *cp && (size_t)(cp - cmdline) < s && n < MAX_MARGV; n++) {
		while (isspace((unsigned char)*cp))
			cp++;
		if (*cp == '\0')
			break;
		*argp++ = cp;
		margc += 1;
		while (*cp != '\0' && !isspace((unsigned char)*cp))
			cp++;
		if (*cp == '\0')
			break;
		*cp++ = '\0';
	}
	*argp++ = 0;
}

#define HELPINDENT (sizeof ("directory"))

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

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

		printf("Commands may be abbreviated.  Commands are:\n\n");
		for (c = cmdtab; c->c_name; c++) {
			size_t 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;
				printf("%s", c->c_name);
				if (c + lines >= &cmdtab[NCMDS - 1]) {
					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 == (struct cmd *)0)
			printf("?Invalid help command %s\n", arg);
		else
			printf("%-*s\t%s\n", (int)HELPINDENT,
				c->c_name, c->c_help);
	}
}

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

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