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      1 /*	$NetBSD: from.c,v 1.17 2008/07/21 14:19:22 lukem Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1988, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1980, 1988, 1993\
     35  The Regents of the University of California.  All rights reserved.");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)from.c	8.1 (Berkeley) 6/6/93";
     41 #endif
     42 __RCSID("$NetBSD: from.c,v 1.17 2008/07/21 14:19:22 lukem Exp $");
     43 #endif /* not lint */
     44 
     45 #include <sys/types.h>
     46 #include <ctype.h>
     47 #include <err.h>
     48 #include <paths.h>
     49 #include <pwd.h>
     50 #include <stdio.h>
     51 #include <stdlib.h>
     52 #include <string.h>
     53 #include <unistd.h>
     54 
     55 int	main (int, char **);
     56 int	match (const char *, const char *);
     57 
     58 int
     59 main(int argc, char **argv)
     60 {
     61 	struct passwd *pwd;
     62 	int ch, newline;
     63 	char *file, *sender, *p;
     64 #if MAXPATHLEN > BUFSIZ
     65 	char buf[MAXPATHLEN];
     66 #else
     67 	char buf[BUFSIZ];
     68 #endif
     69 
     70 	file = sender = NULL;
     71 	while ((ch = getopt(argc, argv, "f:s:")) != -1)
     72 		switch((char)ch) {
     73 		case 'f':
     74 			file = optarg;
     75 			break;
     76 		case 's':
     77 			sender = optarg;
     78 			for (p = sender; *p; ++p)
     79 				*p = tolower((unsigned char)*p);
     80 			break;
     81 		default:
     82 			fprintf(stderr, "usage: from [-f file] [-s sender] [user]\n");
     83 			exit(1);
     84 		}
     85 	argv += optind;
     86 
     87 	/*
     88 	 * We find the mailbox by:
     89 	 *	1 -f flag
     90 	 *	2 user
     91 	 *	2 MAIL environment variable
     92 	 *	3 _PATH_MAILDIR/file
     93 	 */
     94 	if (!file) {
     95 		if (!(file = *argv)) {
     96 			if (!(file = getenv("MAIL"))) {
     97 				if (!(pwd = getpwuid(getuid())))
     98 					errx(1, "no password file entry for you");
     99 				if ((file = getenv("LOGNAME")) != NULL ||
    100 				    (file = getenv("USER")) != NULL) {
    101 					(void)snprintf(buf, sizeof(buf),
    102 					    "%s/%s", _PATH_MAILDIR, file);
    103 					file = buf;
    104 				} else
    105 					(void)snprintf(file = buf, sizeof(buf),
    106 					    "%s/%s",
    107 					    _PATH_MAILDIR, pwd->pw_name);
    108 			}
    109 		} else {
    110 			(void)snprintf(buf, sizeof(buf), "%s/%s",
    111 				_PATH_MAILDIR, file);
    112 			file = buf;
    113 		}
    114 	}
    115 	if (!freopen(file, "r", stdin))
    116 		err(1, "can't read %s", file);
    117 
    118 	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
    119 		if (*buf == '\n') {
    120 			newline = 1;
    121 			continue;
    122 		}
    123 		if (newline && !strncmp(buf, "From ", 5) &&
    124 		    (!sender || match(buf + 5, sender)))
    125 			printf("%s", buf);
    126 		newline = 0;
    127 	}
    128 	exit(0);
    129 }
    130 
    131 int
    132 match(const char *line, const char *sender)
    133 {
    134 	char ch, pch, first;
    135 	const char *p, *t;
    136 
    137 	for (first = *sender++;;) {
    138 		if (isspace((unsigned char)(ch = *line)))
    139 			return(0);
    140 		++line;
    141 		ch = tolower((unsigned char)ch);
    142 		if (ch != first)
    143 			continue;
    144 		for (p = sender, t = line;;) {
    145 			if (!(pch = *p++))
    146 				return(1);
    147 			ch = tolower((unsigned char)*t++);
    148 			if (ch != pch)
    149 				break;
    150 		}
    151 	}
    152 	/* NOTREACHED */
    153 }
    154