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Annotation of 43BSDReno/usr.bin/who/who.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1989 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * This code is derived from software contributed to Berkeley by
                      6:  * Michael Fischbein.
                      7:  *
                      8:  * Redistribution and use in source and binary forms are permitted provided
                      9:  * that: (1) source distributions retain this entire copyright notice and
                     10:  * comment, and (2) distributions including binaries display the following
                     11:  * acknowledgement:  ``This product includes software developed by the
                     12:  * University of California, Berkeley and its contributors'' in the
                     13:  * documentation or other materials provided with the distribution and in
                     14:  * all advertising materials mentioning features or use of this software.
                     15:  * Neither the name of the University nor the names of its contributors may
                     16:  * be used to endorse or promote products derived from this software without
                     17:  * specific prior written permission.
                     18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
                     19:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
                     20:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     21:  */
                     22: 
                     23: #ifndef lint
                     24: char copyright[] =
                     25: "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
                     26:  All rights reserved.\n";
                     27: #endif /* not lint */
                     28: 
                     29: #ifndef lint
                     30: static char sccsid[] = "@(#)who.c      5.11 (Berkeley) 6/1/90";
                     31: #endif /* not lint */
                     32: 
                     33: #include <sys/types.h>
                     34: #include <sys/file.h>
                     35: #include <sys/time.h>
                     36: #include <pwd.h>
                     37: #include <utmp.h>
                     38: #include <stdio.h>
                     39: 
                     40: main(argc, argv)
                     41:        int argc;
                     42:        char **argv;
                     43: {
                     44:        register char *p;
                     45:        struct utmp usr;
                     46:        struct passwd *pw;
                     47:        FILE *ufp, *file();
                     48:        char *t, *rindex(), *strcpy(), *strncpy(), *ttyname();
                     49:        time_t time();
                     50: 
                     51:        switch (argc) {
                     52:        case 1:                                 /* who */
                     53:                ufp = file(_PATH_UTMP);
                     54:                /* only entries with both name and line fields */
                     55:                while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
                     56:                        if (*usr.ut_name && *usr.ut_line)
                     57:                                output(&usr);
                     58:                break;
                     59:        case 2:                                 /* who utmp_file */
                     60:                ufp = file(argv[1]);
                     61:                /* all entries */
                     62:                while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
                     63:                        output(&usr);
                     64:                break;
                     65:        case 3:                                 /* who am i */
                     66:                ufp = file(_PATH_UTMP);
                     67: 
                     68:                /* search through the utmp and find an entry for this tty */
                     69:                if (p = ttyname(0)) {
                     70:                        /* strip any directory component */
                     71:                        if (t = rindex(p, '/'))
                     72:                                p = t + 1;
                     73:                        while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
                     74:                                if (usr.ut_name && !strcmp(usr.ut_line, p)) {
                     75:                                        output(&usr);
                     76:                                        exit(0);
                     77:                                }
                     78:                        /* well, at least we know what the tty is */
                     79:                        (void)strncpy(usr.ut_line, p, UT_LINESIZE);
                     80:                } else
                     81:                        (void)strcpy(usr.ut_line, "tty??");
                     82:                pw = getpwuid(getuid());
                     83:                (void)strncpy(usr.ut_name, pw ? pw->pw_name : "?", UT_NAMESIZE);
                     84:                (void)time(&usr.ut_time);
                     85:                *usr.ut_host = '\0';
                     86:                output(&usr);
                     87:                break;
                     88:        default:
                     89:                (void)fprintf(stderr, "usage: who [ file ]\n       who am i\n");
                     90:                exit(1);
                     91:        }
                     92:        exit(0);
                     93: }
                     94: 
                     95: output(up)
                     96:        struct utmp *up;
                     97: {
                     98:        char *ctime();
                     99: 
                    100:        (void)printf("%-*.*s %-*.*s", UT_NAMESIZE, UT_NAMESIZE, up->ut_name,
                    101:            UT_LINESIZE, UT_LINESIZE, up->ut_line);
                    102:        (void)printf("%.12s", ctime(&up->ut_time) + 4);
                    103:        if (*up->ut_host)
                    104:                printf("\t(%.*s)", UT_HOSTSIZE, up->ut_host);
                    105:        (void)putchar('\n');
                    106: }
                    107: 
                    108: FILE *
                    109: file(name)
                    110:        char *name;
                    111: {
                    112:        extern int errno;
                    113:        FILE *ufp;
                    114:        char *strerror();
                    115: 
                    116:        if (!(ufp = fopen(name, "r"))) {
                    117:                (void)fprintf(stderr, "who: %s: %s.\n", name, strerror(errno));
                    118:                exit(1);
                    119:        }
                    120:        return(ufp);
                    121: }

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