ubase/su.c
2014-07-09 15:08:01 +01:00

128 lines
2.4 KiB
C

/* See LICENSE file for copyright and license details. */
#include <sys/types.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "config.h"
#include "passwd.h"
#include "util.h"
extern char **environ;
static int dologin(struct passwd *);
static void
usage(void)
{
eprintf("usage: %s [-lp] [username]\n", argv0);
}
static int lflag = 0;
static int pflag = 0;
int
main(int argc, char *argv[])
{
char *usr = "root", *pass;
char *shell;
struct passwd *pw;
char *newargv[2];
uid_t uid;
ARGBEGIN {
case 'l':
lflag = 1;
break;
case 'p':
pflag = 1;
break;
default:
usage();
} ARGEND;
if (argc < 1)
;
else if (argc == 1)
usr = argv[0];
else
usage();
errno = 0;
pw = getpwnam(usr);
if (!pw) {
if (errno)
eprintf("getpwnam: %s:", usr);
else
eprintf("who are you?\n");
}
uid = getuid();
if (uid) {
pass = getpass("Password: "); putchar('\n');
if (!pass)
eprintf("getpass:");
if (pw_check(pw, pass) <= 0)
exit(EXIT_FAILURE);
}
if (initgroups(usr, pw->pw_gid) < 0)
eprintf("initgroups:");
if (setgid(pw->pw_gid) < 0)
eprintf("setgid:");
if (setuid(pw->pw_uid) < 0)
eprintf("setuid:");
if (lflag) {
return dologin(pw);
} else {
shell = pw->pw_shell[0] == '\0' ? "/bin/sh" : pw->pw_shell;
newargv[0] = shell;
newargv[1] = NULL;
if (!pflag) {
setenv("HOME", pw->pw_dir, 1);
setenv("SHELL", shell, 1);
if (strcmp(pw->pw_name, "root") != 0) {
setenv("USER", pw->pw_name, 1);
setenv("LOGNAME", pw->pw_name, 1);
}
}
if (strcmp(pw->pw_name, "root") == 0)
setenv("PATH", ENV_SUPATH, 1);
else
setenv("PATH", ENV_PATH, 1);
execve(pflag ? getenv("SHELL") : shell,
newargv, environ);
weprintf("execve %s:", shell);
return (errno == ENOENT) ? 127 : 126;
}
return EXIT_SUCCESS;
}
static int
dologin(struct passwd *pw)
{
char *shell = pw->pw_shell[0] == '\0' ? "/bin/sh" : pw->pw_shell;
char *term = getenv("TERM");
clearenv();
setenv("HOME", pw->pw_dir, 1);
setenv("SHELL", shell, 1);
setenv("USER", pw->pw_name, 1);
setenv("LOGNAME", pw->pw_name, 1);
setenv("TERM", term ? term : "linux", 1);
if (strcmp(pw->pw_name, "root") == 0)
setenv("PATH", ENV_SUPATH, 1);
else
setenv("PATH", ENV_PATH, 1);
if (chdir(pw->pw_dir) < 0)
eprintf("chdir %s:", pw->pw_dir);
execlp(shell, shell, "-l", NULL);
weprintf("execlp %s:", shell);
return (errno == ENOENT) ? 127 : 126;
}