Annotation of src/usr.bin/users/users.c, Revision 1.14
1.14 ! deraadt 1: /* $OpenBSD: users.c,v 1.13 2015/10/09 01:37:09 deraadt Exp $ */
1.1 deraadt 2: /* $NetBSD: users.c,v 1.5 1994/12/20 15:58:19 jtc Exp $ */
3:
4: /*
5: * Copyright (c) 1980, 1987, 1993
6: * The Regents of the University of California. All rights reserved.
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.
1.7 millert 16: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 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/types.h>
1.10 millert 34:
35: #include <err.h>
1.1 deraadt 36: #include <stdio.h>
37: #include <stdlib.h>
38: #include <string.h>
1.10 millert 39: #include <unistd.h>
40: #include <utmp.h>
1.1 deraadt 41:
42: typedef char namebuf[UT_NAMESIZE];
43:
1.5 millert 44: int scmp(const void *, const void *);
1.1 deraadt 45:
46: int
1.6 deraadt 47: main(int argc, char *argv[])
1.1 deraadt 48: {
49: namebuf *names = NULL;
1.4 mpech 50: int ncnt = 0;
51: int nmax = 0;
1.1 deraadt 52: int cnt;
53: struct utmp utmp;
54: int ch;
1.12 deraadt 55:
1.14 ! deraadt 56: if (unveil(_PATH_UTMP, "r") == -1)
! 57: err(1, "unveil");
1.13 deraadt 58: if (pledge("stdio rpath", NULL) == -1)
59: err(1, "pledge");
1.1 deraadt 60:
1.3 millert 61: while ((ch = getopt(argc, argv, "")) != -1)
1.1 deraadt 62: switch(ch) {
63: case '?':
64: default:
65: (void)fprintf(stderr, "usage: users\n");
66: exit(1);
67: }
68: argc -= optind;
69: argv += optind;
70:
71: if (!freopen(_PATH_UTMP, "r", stdin)) {
72: err(1, "can't open %s", _PATH_UTMP);
73: /* NOTREACHED */
74: }
75:
76: while (fread((char *)&utmp, sizeof(utmp), 1, stdin) == 1) {
77: if (*utmp.ut_name) {
78: if (ncnt >= nmax) {
1.8 tedu 79: size_t newmax = nmax + 32;
80: namebuf *newnames;
1.1 deraadt 81:
1.11 doug 82: newnames = reallocarray(names, newmax,
83: sizeof(*names));
1.8 tedu 84:
85: if (newnames == NULL) {
1.1 deraadt 86: err(1, NULL);
87: /* NOTREACHED */
88: }
1.8 tedu 89: names = newnames;
90: nmax = newmax;
1.1 deraadt 91: }
92:
93: (void)strncpy(names[ncnt], utmp.ut_name, UT_NAMESIZE);
94: ++ncnt;
95: }
96: }
97:
98: if (ncnt) {
99: qsort(names, ncnt, UT_NAMESIZE, scmp);
100: (void)printf("%.*s", UT_NAMESIZE, names[0]);
101: for (cnt = 1; cnt < ncnt; ++cnt)
102: if (strncmp(names[cnt], names[cnt - 1], UT_NAMESIZE))
103: (void)printf(" %.*s", UT_NAMESIZE, names[cnt]);
104: (void)printf("\n");
105: }
106: exit(0);
107: }
108:
109: int
1.6 deraadt 110: scmp(const void *p, const void *q)
1.1 deraadt 111: {
112: return(strncmp((char *) p, (char *) q, UT_NAMESIZE));
113: }