1 static char *sccsid = "@(#)who.c 4.4 (Berkeley) 03/15/82"; 2 /* 3 * who 4 */ 5 6 #include <stdio.h> 7 #include <utmp.h> 8 #include <pwd.h> 9 #include <ctype.h> 10 11 #define NMAX sizeof(utmp.ut_name) 12 #define LMAX sizeof(utmp.ut_line) 13 14 struct utmp utmp; 15 struct passwd *pw; 16 struct passwd *getpwuid(); 17 char hostname[32]; 18 19 char *ttyname(), *rindex(), *ctime(), *strcpy(); 20 21 main(argc, argv) 22 int argc; 23 char **argv; 24 { 25 register char *tp, *s; 26 register FILE *fi; 27 extern char _sobuf[]; 28 29 setbuf(stdout, _sobuf); 30 s = "/etc/utmp"; 31 if(argc == 2) 32 s = argv[1]; 33 if (argc==3) { 34 tp = ttyname(0); 35 if (tp) 36 tp = rindex(tp, '/') + 1; 37 else { /* no tty - use best guess from passwd file */ 38 pw = getpwuid(getuid()); 39 strcpy(utmp.ut_name, pw?pw->pw_name: "?"); 40 strcpy(utmp.ut_line, "tty??"); 41 time(&utmp.ut_time); 42 putline(); 43 exit(0); 44 } 45 } 46 if ((fi = fopen(s, "r")) == NULL) { 47 puts("who: cannot open utmp"); 48 exit(1); 49 } 50 while (fread((char *)&utmp, sizeof(utmp), 1, fi) == 1) { 51 if(argc==3) { 52 gethostname(hostname, sizeof (hostname)); 53 if (strcmp(utmp.ut_line, tp)) 54 continue; 55 printf("%s!", hostname); 56 putline(); 57 exit(0); 58 } 59 if(utmp.ut_name[0] == '\0' && argc==1) 60 continue; 61 putline(); 62 } 63 } 64 65 putline() 66 { 67 register char *cbuf; 68 69 printf("%-*.*s %-*.*s", NMAX, NMAX, utmp.ut_name, LMAX, LMAX, utmp.ut_line); 70 cbuf = ctime(&utmp.ut_time); 71 printf("%.12s\n", cbuf+4); 72 } 73