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lpc.c revision 1.16 
      1 /*	$NetBSD: lpc.c,v 1.16 2004/10/30 08:44:26 dsl Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the University nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 #ifndef lint
     35 __COPYRIGHT("@(#) Copyright (c) 1983, 1993\n\
     36 	The Regents of the University of California.  All rights reserved.\n");
     37 #if 0
     38 static char sccsid[] = "@(#)lpc.c	8.3 (Berkeley) 4/28/95";
     39 #else
     40 __RCSID("$NetBSD: lpc.c,v 1.16 2004/10/30 08:44:26 dsl Exp $");
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include <sys/param.h>
     45 
     46 #include <dirent.h>
     47 #include <signal.h>
     48 #include <setjmp.h>
     49 #include <syslog.h>
     50 #include <unistd.h>
     51 #include <stdlib.h>
     52 #include <stdio.h>
     53 #include <ctype.h>
     54 #include <string.h>
     55 #include <grp.h>
     56 #include <err.h>
     57 #include "lp.h"
     58 #include "lpc.h"
     59 #include "extern.h"
     60 
     61 #ifndef LPR_OPER
     62 #define LPR_OPER	"operator"	/* group name of lpr operators */
     63 #endif
     64 
     65 /*
     66  * lpc -- line printer control program
     67  */
     68 
     69 #define MAX_CMDLINE	200
     70 #define MAX_MARGV	20
     71 int	fromatty;
     72 
     73 char	cmdline[MAX_CMDLINE];
     74 int	margc;
     75 char	*margv[MAX_MARGV];
     76 int	top;
     77 uid_t	uid, euid;
     78 
     79 jmp_buf	toplevel;
     80 
     81 static void		 cmdscanner(int);
     82 static struct cmd	*getcmd(char *);
     83 static void		 intr(int);
     84 static void		 makeargv(void);
     85 static int		 ingroup(char *);
     86 int			 main(int, char *p[]);
     87 
     88 int
     89 main(int argc, char *argv[])
     90 {
     91 	struct cmd *c;
     92 
     93 	euid = geteuid();
     94 	uid = getuid();
     95 	seteuid(uid);
     96 	name = argv[0];
     97 	openlog("lpd", 0, LOG_LPR);
     98 
     99 	if (--argc > 0) {
    100 		c = getcmd(*++argv);
    101 		if (c == (struct cmd *)-1) {
    102 			printf("?Ambiguous command\n");
    103 			exit(1);
    104 		}
    105 		if (c == 0) {
    106 			printf("?Invalid command\n");
    107 			exit(1);
    108 		}
    109 		if (c->c_priv && getuid() && ingroup(LPR_OPER) == 0) {
    110 			printf("?Privileged command\n");
    111 			exit(1);
    112 		}
    113 		(*c->c_handler)(argc, argv);
    114 		exit(0);
    115 	}
    116 	fromatty = isatty(fileno(stdin));
    117 	top = setjmp(toplevel) == 0;
    118 	if (top)
    119 		signal(SIGINT, intr);
    120 	for (;;) {
    121 		cmdscanner(top);
    122 		top = 1;
    123 	}
    124 }
    125 
    126 static void
    127 intr(int signo)
    128 {
    129 	if (!fromatty)
    130 		exit(0);
    131 	longjmp(toplevel, 1);
    132 }
    133 
    134 /*
    135  * Command parser.
    136  */
    137 static void
    138 cmdscanner(int top)
    139 {
    140 	struct cmd *c;
    141 
    142 	if (!top)
    143 		putchar('\n');
    144 	for (;;) {
    145 		if (fromatty) {
    146 			printf("lpc> ");
    147 			fflush(stdout);
    148 		}
    149 		if (fgets(cmdline, MAX_CMDLINE, stdin) == 0)
    150 			quit(0, NULL);
    151 		makeargv();
    152 		if (margc == 0)
    153 			break;
    154 		c = getcmd(margv[0]);
    155 		if (c == (struct cmd *)-1) {
    156 			printf("?Ambiguous command\n");
    157 			continue;
    158 		}
    159 		if (c == 0) {
    160 			printf("?Invalid command\n");
    161 			continue;
    162 		}
    163 		if (c->c_priv && getuid() && ingroup(LPR_OPER) == 0) {
    164 			printf("?Privileged command\n");
    165 			continue;
    166 		}
    167 		(*c->c_handler)(margc, margv);
    168 	}
    169 	longjmp(toplevel, 0);
    170 }
    171 
    172 static struct cmd *
    173 getcmd(char *name)
    174 {
    175 	char *p, *q;
    176 	struct cmd *c, *found;
    177 	int nmatches, longest;
    178 
    179 	longest = 0;
    180 	nmatches = 0;
    181 	found = 0;
    182 	for (c = cmdtab; (p = c->c_name) != NULL; c++) {
    183 		for (q = name; *q == *p++; q++)
    184 			if (*q == 0)		/* exact match? */
    185 				return(c);
    186 		if (!*q) {			/* the name was a prefix */
    187 			if (q - name > longest) {
    188 				longest = q - name;
    189 				nmatches = 1;
    190 				found = c;
    191 			} else if (q - name == longest)
    192 				nmatches++;
    193 		}
    194 	}
    195 	if (nmatches > 1)
    196 		return((struct cmd *)-1);
    197 	return(found);
    198 }
    199 
    200 /*
    201  * Slice a string up into argc/argv.
    202  */
    203 static void
    204 makeargv(void)
    205 {
    206 	char *cp;
    207 	char **argp = margv;
    208 	int n = 0;
    209 
    210 	margc = 0;
    211 	for (cp = cmdline; *cp && (cp - cmdline) < sizeof(cmdline) &&
    212 	    n < MAX_MARGV; n++) {
    213 		while (isspace((unsigned char)*cp))
    214 			cp++;
    215 		if (*cp == '\0')
    216 			break;
    217 		*argp++ = cp;
    218 		margc += 1;
    219 		while (*cp != '\0' && !isspace((unsigned char)*cp))
    220 			cp++;
    221 		if (*cp == '\0')
    222 			break;
    223 		*cp++ = '\0';
    224 	}
    225 	*argp++ = 0;
    226 }
    227 
    228 #define HELPINDENT (sizeof ("directory"))
    229 
    230 /*
    231  * Help command.
    232  */
    233 void
    234 help(int argc, char *argv[])
    235 {
    236 	struct cmd *c;
    237 
    238 	if (argc == 1) {
    239 		int i, j, w;
    240 		int columns, width = 0, lines;
    241 
    242 		printf("Commands may be abbreviated.  Commands are:\n\n");
    243 		for (c = cmdtab; c->c_name; c++) {
    244 			int len = strlen(c->c_name);
    245 
    246 			if (len > width)
    247 				width = len;
    248 		}
    249 		width = (width + 8) &~ 7;
    250 		columns = 80 / width;
    251 		if (columns == 0)
    252 			columns = 1;
    253 		lines = (NCMDS + columns - 1) / columns;
    254 		for (i = 0; i < lines; i++) {
    255 			for (j = 0; j < columns; j++) {
    256 				c = cmdtab + j * lines + i;
    257 				if (c->c_name)
    258 					printf("%s", c->c_name);
    259 				if (c + lines >= &cmdtab[NCMDS]) {
    260 					printf("\n");
    261 					break;
    262 				}
    263 				w = strlen(c->c_name);
    264 				while (w < width) {
    265 					w = (w + 8) &~ 7;
    266 					putchar('\t');
    267 				}
    268 			}
    269 		}
    270 		return;
    271 	}
    272 	while (--argc > 0) {
    273 		char *arg;
    274 		arg = *++argv;
    275 		c = getcmd(arg);
    276 		if (c == (struct cmd *)-1)
    277 			printf("?Ambiguous help command %s\n", arg);
    278 		else if (c == (struct cmd *)0)
    279 			printf("?Invalid help command %s\n", arg);
    280 		else
    281 			printf("%-*s\t%s\n", (int)HELPINDENT,
    282 				c->c_name, c->c_help);
    283 	}
    284 }
    285 
    286 /*
    287  * return non-zero if the user is a member of the given group
    288  */
    289 static int
    290 ingroup(char *grname)
    291 {
    292 	static struct group *gptr=NULL;
    293 	static gid_t groups[NGROUPS];
    294 	static int ngroups;
    295 	gid_t gid;
    296 	int i;
    297 
    298 	if (gptr == NULL) {
    299 		if ((gptr = getgrnam(grname)) == NULL) {
    300 			warnx("Warning: unknown group `%s'",
    301 				grname);
    302 			return(0);
    303 		}
    304 		ngroups = getgroups(NGROUPS, groups);
    305 		if (ngroups < 0)
    306 			err(1, "getgroups");
    307 	}
    308 	gid = gptr->gr_gid;
    309 	for (i = 0; i < ngroups; i++)
    310 		if (gid == groups[i])
    311 			return(1);
    312 	return(0);
    313 }
    314