whoami.c (582B)
1 /* See LICENSE file for copyright and license details. */ 2 #include <errno.h> 3 #include <stdio.h> 4 #include <unistd.h> 5 #include <pwd.h> 6 7 #include "util.h" 8 9 static void 10 usage(void) 11 { 12 eprintf("usage: %s\n", argv0); 13 } 14 15 int 16 main(int argc, char *argv[]) 17 { 18 uid_t uid; 19 struct passwd *pw; 20 21 argv0 = *argv, argv0 ? (argc--, argv++) : (void *)0; 22 23 if (argc) 24 usage(); 25 26 uid = geteuid(); 27 errno = 0; 28 if (!(pw = getpwuid(uid))) { 29 if (errno) 30 eprintf("getpwuid %d:", uid); 31 else 32 eprintf("getpwuid %d: no such user\n", uid); 33 } 34 puts(pw->pw_name); 35 36 return fshut(stdout, "<stdout>"); 37 }