1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Michael Fischbein.
7 *
8 * %sccs.include.redist.c%
9 */
10
11 #ifndef lint
12 static char copyright[] =
13 "@(#) Copyright (c) 1989, 1993\n\
14 The Regents of the University of California. All rights reserved.\n";
15 #endif /* not lint */
16
17 #ifndef lint
18 static char sccsid[] = "@(#)who.c 8.1 (Berkeley) 06/06/93";
19 #endif /* not lint */
20
21 #include <sys/types.h>
22 #include <sys/file.h>
23 #include <sys/time.h>
24 #include <pwd.h>
25 #include <utmp.h>
26 #include <stdio.h>
27
main(argc,argv)28 main(argc, argv)
29 int argc;
30 char **argv;
31 {
32 register char *p;
33 struct utmp usr;
34 struct passwd *pw;
35 FILE *ufp, *file();
36 char *t, *rindex(), *strcpy(), *strncpy(), *ttyname();
37 time_t time();
38
39 switch (argc) {
40 case 1: /* who */
41 ufp = file(_PATH_UTMP);
42 /* only entries with both name and line fields */
43 while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
44 if (*usr.ut_name && *usr.ut_line)
45 output(&usr);
46 break;
47 case 2: /* who utmp_file */
48 ufp = file(argv[1]);
49 /* all entries */
50 while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
51 output(&usr);
52 break;
53 case 3: /* who am i */
54 ufp = file(_PATH_UTMP);
55
56 /* search through the utmp and find an entry for this tty */
57 if (p = ttyname(0)) {
58 /* strip any directory component */
59 if (t = rindex(p, '/'))
60 p = t + 1;
61 while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
62 if (usr.ut_name && !strcmp(usr.ut_line, p)) {
63 output(&usr);
64 exit(0);
65 }
66 /* well, at least we know what the tty is */
67 (void)strncpy(usr.ut_line, p, UT_LINESIZE);
68 } else
69 (void)strcpy(usr.ut_line, "tty??");
70 pw = getpwuid(getuid());
71 (void)strncpy(usr.ut_name, pw ? pw->pw_name : "?", UT_NAMESIZE);
72 (void)time(&usr.ut_time);
73 *usr.ut_host = '\0';
74 output(&usr);
75 break;
76 default:
77 (void)fprintf(stderr, "usage: who [ file ]\n who am i\n");
78 exit(1);
79 }
80 exit(0);
81 }
82
83 output(up)
84 struct utmp *up;
85 {
86 char *ctime();
87
88 (void)printf("%-*.*s %-*.*s", UT_NAMESIZE, UT_NAMESIZE, up->ut_name,
89 UT_LINESIZE, UT_LINESIZE, up->ut_line);
90 (void)printf("%.12s", ctime(&up->ut_time) + 4);
91 if (*up->ut_host)
92 printf("\t(%.*s)", UT_HOSTSIZE, up->ut_host);
93 (void)putchar('\n');
94 }
95
96 FILE *
file(name)97 file(name)
98 char *name;
99 {
100 extern int errno;
101 FILE *ufp;
102 char *strerror();
103
104 if (!(ufp = fopen(name, "r"))) {
105 (void)fprintf(stderr, "who: %s: %s.\n", name, strerror(errno));
106 exit(1);
107 }
108 return(ufp);
109 }
110