morpheus-base

morpheus base system
git clone git://git.2f30.org/morpheus-base.git
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su.c (2453B)


      1 /* See LICENSE file for copyright and license details. */
      2 #include <sys/types.h>
      3 
      4 #include <errno.h>
      5 #include <grp.h>
      6 #include <pwd.h>
      7 #include <stdio.h>
      8 #include <stdlib.h>
      9 #include <string.h>
     10 #include <unistd.h>
     11 
     12 #include "config.h"
     13 #include "passwd.h"
     14 #include "util.h"
     15 
     16 extern char **environ;
     17 
     18 static int dologin(struct passwd *);
     19 
     20 static void
     21 usage(void)
     22 {
     23 	eprintf("usage: %s [-lp] [username]\n", argv0);
     24 }
     25 
     26 static int lflag = 0;
     27 static int pflag = 0;
     28 
     29 int
     30 main(int argc, char *argv[])
     31 {
     32 	char *usr = "root", *pass;
     33 	char *shell;
     34 	struct passwd *pw;
     35 	char *newargv[2];
     36 	uid_t uid;
     37 
     38 	ARGBEGIN {
     39 	case 'l':
     40 		lflag = 1;
     41 		break;
     42 	case 'p':
     43 		pflag = 1;
     44 		break;
     45 	default:
     46 		usage();
     47 	} ARGEND;
     48 
     49 	if (argc < 1)
     50 		;
     51 	else if (argc == 1)
     52 		usr = argv[0];
     53 	else
     54 		usage();
     55 
     56 	errno = 0;
     57 	pw = getpwnam(usr);
     58 	if (!pw) {
     59 		if (errno)
     60 			eprintf("getpwnam: %s:", usr);
     61 		else
     62 			eprintf("who are you?\n");
     63 	}
     64 
     65 	uid = getuid();
     66 	if (uid) {
     67 		pass = getpass("Password: ");
     68 		if (!pass)
     69 			eprintf("getpass:");
     70 		if (pw_check(pw, pass) <= 0)
     71 			exit(1);
     72 	}
     73 
     74 	if (initgroups(usr, pw->pw_gid) < 0)
     75 		eprintf("initgroups:");
     76 	if (setgid(pw->pw_gid) < 0)
     77 		eprintf("setgid:");
     78 	if (setuid(pw->pw_uid) < 0)
     79 		eprintf("setuid:");
     80 
     81 	if (lflag) {
     82 		return dologin(pw);
     83 	} else {
     84 		shell = pw->pw_shell[0] == '\0' ? "/bin/sh" : pw->pw_shell;
     85 		newargv[0] = shell;
     86 		newargv[1] = NULL;
     87 		if (!pflag) {
     88 			setenv("HOME", pw->pw_dir, 1);
     89 			setenv("SHELL", shell, 1);
     90 			if (strcmp(pw->pw_name, "root") != 0) {
     91 				setenv("USER", pw->pw_name, 1);
     92 				setenv("LOGNAME", pw->pw_name, 1);
     93 			}
     94 		}
     95 		if (strcmp(pw->pw_name, "root") == 0)
     96 			setenv("PATH", ENV_SUPATH, 1);
     97 		else
     98 			setenv("PATH", ENV_PATH, 1);
     99 		execve(pflag ? getenv("SHELL") : shell,
    100 		       newargv, environ);
    101 		weprintf("execve %s:", shell);
    102 		return (errno == ENOENT) ? 127 : 126;
    103 	}
    104 	return 0;
    105 }
    106 
    107 static int
    108 dologin(struct passwd *pw)
    109 {
    110 	char *shell = pw->pw_shell[0] == '\0' ? "/bin/sh" : pw->pw_shell;
    111 	char *term = getenv("TERM");
    112 	clearenv();
    113 	setenv("HOME", pw->pw_dir, 1);
    114 	setenv("SHELL", shell, 1);
    115 	setenv("USER", pw->pw_name, 1);
    116 	setenv("LOGNAME", pw->pw_name, 1);
    117 	setenv("TERM", term ? term : "linux", 1);
    118 	if (strcmp(pw->pw_name, "root") == 0)
    119 		setenv("PATH", ENV_SUPATH, 1);
    120 	else
    121 		setenv("PATH", ENV_PATH, 1);
    122 	if (chdir(pw->pw_dir) < 0)
    123 		eprintf("chdir %s:", pw->pw_dir);
    124 	execlp(shell, shell, "-l", NULL);
    125 	weprintf("execlp %s:", shell);
    126 	return (errno == ENOENT) ? 127 : 126;
    127 }