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from.c revision 1.13 
      1 /*	$NetBSD: from.c,v 1.13 2001/07/01 00:09:46 mjl 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 __COPYRIGHT("@(#) Copyright (c) 1980, 1988, 1993\n\
     39 	The Regents of the University of California.  All rights reserved.\n");
     40 #endif /* not lint */
     41 
     42 #ifndef lint
     43 #if 0
     44 static char sccsid[] = "@(#)from.c	8.1 (Berkeley) 6/6/93";
     45 #endif
     46 __RCSID("$NetBSD: from.c,v 1.13 2001/07/01 00:09:46 mjl Exp $");
     47 #endif /* not lint */
     48 
     49 #include <sys/types.h>
     50 #include <ctype.h>
     51 #include <err.h>
     52 #include <paths.h>
     53 #include <pwd.h>
     54 #include <stdio.h>
     55 #include <stdlib.h>
     56 #include <string.h>
     57 #include <unistd.h>
     58 
     59 int	main (int, char **);
     60 int	match (const char *, const char *);
     61 
     62 int
     63 main(int argc, char **argv)
     64 {
     65 	struct passwd *pwd;
     66 	int ch, newline;
     67 	char *file, *sender, *p;
     68 #if MAXPATHLEN > BUFSIZ
     69 	char buf[MAXPATHLEN];
     70 #else
     71 	char buf[BUFSIZ];
     72 #endif
     73 
     74 	file = sender = NULL;
     75 	while ((ch = getopt(argc, argv, "f:s:")) != -1)
     76 		switch((char)ch) {
     77 		case 'f':
     78 			file = optarg;
     79 			break;
     80 		case 's':
     81 			sender = optarg;
     82 			for (p = sender; *p; ++p)
     83 				if (isupper((unsigned char)*p))
     84 					*p = tolower(*p);
     85 			break;
     86 		default:
     87 			fprintf(stderr, "usage: from [-f file] [-s sender] [user]\n");
     88 			exit(1);
     89 		}
     90 	argv += optind;
     91 
     92 	/*
     93 	 * We find the mailbox by:
     94 	 *	1 -f flag
     95 	 *	2 user
     96 	 *	2 MAIL environment variable
     97 	 *	3 _PATH_MAILDIR/file
     98 	 */
     99 	if (!file) {
    100 		if (!(file = *argv)) {
    101 			if (!(file = getenv("MAIL"))) {
    102 				if (!(pwd = getpwuid(getuid())))
    103 					errx(1, "no password file entry for you");
    104 				if ((file = getenv("USER")) != NULL) {
    105 					(void)snprintf(buf, sizeof(buf),
    106 					    "%s/%s", _PATH_MAILDIR, file);
    107 					file = buf;
    108 				} else
    109 					(void)snprintf(file = buf, sizeof(buf),
    110 					    "%s/%s",
    111 					    _PATH_MAILDIR, pwd->pw_name);
    112 			}
    113 		} else {
    114 			(void)snprintf(buf, sizeof(buf), "%s/%s",
    115 				_PATH_MAILDIR, file);
    116 			file = buf;
    117 		}
    118 	}
    119 	if (!freopen(file, "r", stdin))
    120 		err(1, "can't read %s", file);
    121 
    122 	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
    123 		if (*buf == '\n') {
    124 			newline = 1;
    125 			continue;
    126 		}
    127 		if (newline && !strncmp(buf, "From ", 5) &&
    128 		    (!sender || match(buf + 5, sender)))
    129 			printf("%s", buf);
    130 		newline = 0;
    131 	}
    132 	exit(0);
    133 }
    134 
    135 int
    136 match(const char *line, const char *sender)
    137 {
    138 	char ch, pch, first;
    139 	const char *p, *t;
    140 
    141 	for (first = *sender++;;) {
    142 		if (isspace((unsigned char)(ch = *line)))
    143 			return(0);
    144 		++line;
    145 		if (isupper((unsigned char)ch))
    146 			ch = tolower(ch);
    147 		if (ch != first)
    148 			continue;
    149 		for (p = sender, t = line;;) {
    150 			if (!(pch = *p++))
    151 				return(1);
    152 			if (isupper((unsigned char)(ch = *t++)))
    153 				ch = tolower(ch);
    154 			if (ch != pch)
    155 				break;
    156 		}
    157 	}
    158 	/* NOTREACHED */
    159 }
    160