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from.c revision 1.3 
      1 /*
      2  * Copyright (c) 1980, 1988 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 char copyright[] =
     36 "@(#) Copyright (c) 1980, 1988 The Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 /*static char sccsid[] = "from: @(#)from.c	5.7 (Berkeley) 3/1/91";*/
     42 static char rcsid[] = "$Id: from.c,v 1.3 1994/01/25 08:44:44 deraadt Exp $";
     43 #endif /* not lint */
     44 
     45 #include <sys/types.h>
     46 #include <ctype.h>
     47 #include <pwd.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include <unistd.h>
     51 #include <paths.h>
     52 
     53 main(argc, argv)
     54 	int argc;
     55 	char **argv;
     56 {
     57 	extern char *optarg;
     58 	extern int optind;
     59 	struct passwd *pwd;
     60 	int ch, newline;
     61 	char *file, *sender, *p;
     62 #if MAXPATHLEN > BUFSIZ
     63 	char buf[MAXPATHLEN];
     64 #else
     65 	char buf[BUFSIZ];
     66 #endif
     67 
     68 	file = sender = NULL;
     69 	while ((ch = getopt(argc, argv, "f:s:")) != EOF)
     70 		switch((char)ch) {
     71 		case 'f':
     72 			file = optarg;
     73 			break;
     74 		case 's':
     75 			sender = optarg;
     76 			for (p = sender; *p; ++p)
     77 				if (isupper(*p))
     78 					*p = tolower(*p);
     79 			break;
     80 		case '?':
     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 					(void)fprintf(stderr,
     99 				"from: no password file entry for you.\n");
    100 					exit(1);
    101 				}
    102 				(void)sprintf(file = buf, "%s/%s",
    103 					      _PATH_MAILDIR, pwd->pw_name);
    104 			}
    105 		}
    106 		else
    107 			(void)sprintf(file = buf, "%s/%s", _PATH_MAILDIR, file);
    108 	}
    109 	if (!freopen(file, "r", stdin)) {
    110 		(void)fprintf(stderr, "from: can't read %s.\n", file);
    111 		exit(1);
    112 	}
    113 	for (newline = 1; fgets(buf, sizeof(buf), stdin);) {
    114 		if (*buf == '\n') {
    115 			newline = 1;
    116 			continue;
    117 		}
    118 		if (newline && !strncmp(buf, "From ", 5) &&
    119 		    (!sender || match(buf + 5, sender)))
    120 			printf("%s", buf);
    121 		newline = 0;
    122 	}
    123 	exit(0);
    124 }
    125 
    126 match(line, sender)
    127 	register char *line, *sender;
    128 {
    129 	register char ch, pch, first, *p, *t;
    130 
    131 	for (first = *sender++;;) {
    132 		if (isspace(ch = *line))
    133 			return(0);
    134 		++line;
    135 		if (isupper(ch))
    136 			ch = tolower(ch);
    137 		if (ch != first)
    138 			continue;
    139 		for (p = sender, t = line;;) {
    140 			if (!(pch = *p++))
    141 				return(1);
    142 			if (isupper(ch = *t++))
    143 				ch = tolower(ch);
    144 			if (ch != pch)
    145 				break;
    146 		}
    147 	}
    148 	/* NOTREACHED */
    149 }
    150