ubase/login.c

127 lines
2.4 KiB
C

/* See LICENSE file for copyright and license details. */
#define _XOPEN_SOURCE
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <shadow.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <unistd.h>
#include "config.h"
#include "util.h"
static int dologin(struct passwd *, int);
static void
usage(void)
{
eprintf("usage: %s [-p] username\n", argv0);
}
int
main(int argc, char *argv[])
{
struct passwd *pw;
struct spwd *spw;
char *pass, *cryptpass;
uid_t uid;
gid_t gid;
int pflag = 0;
ARGBEGIN {
case 'p':
pflag = 1;
break;
default:
usage();
} ARGEND;
if (argc < 1)
usage();
if (isatty(STDIN_FILENO) == 0)
eprintf("stdin is not a tty\n");
errno = 0;
pw = getpwnam(argv[0]);
if (errno)
eprintf("getpwnam: %s:", argv[0]);
else if (!pw)
eprintf("who are you?\n");
switch (pw->pw_passwd[0]) {
case '!':
case '*':
eprintf("denied\n");
}
uid = pw->pw_uid;
gid = pw->pw_gid;
/* Empty password? Login now */
if (pw->pw_passwd[0] == '\0')
goto login;
/* Flush pending input */
ioctl(STDIN_FILENO, TCFLSH, (void *)0);
pass = getpass("Password: ");
if (!pass)
eprintf("getpass:");
if (pw->pw_passwd[0] == 'x' && pw->pw_passwd[1] == '\0') {
errno = 0;
spw = getspnam(argv[0]);
if (errno)
eprintf("getspnam: %s:", argv[0]);
else if (!spw)
eprintf("who are you?\n");
switch (spw->sp_pwdp[0]) {
case '!':
case '*':
eprintf("denied\n");
}
cryptpass = crypt(pass, spw->sp_pwdp);
if (!cryptpass)
eprintf("crypt:");
if (strcmp(cryptpass, spw->sp_pwdp) != 0)
eprintf("login failed\n");
} else {
cryptpass = crypt(pass, pw->pw_passwd);
if (!cryptpass)
eprintf("crypt:");
if (strcmp(cryptpass, pw->pw_passwd) != 0)
eprintf("login failed\n");
}
login:
if (initgroups(argv[0], gid) < 0)
eprintf("initgroups:");
if (setgid(gid) < 0)
eprintf("setgid:");
if (setuid(uid) < 0)
eprintf("setuid:");
return dologin(pw, pflag);
}
static int
dologin(struct passwd *pw, int preserve)
{
if (preserve == 0)
clearenv();
setenv("HOME", pw->pw_dir, !preserve);
setenv("SHELL", pw->pw_shell, !preserve);
setenv("USER", pw->pw_name, !preserve);
setenv("LOGNAME", pw->pw_name, !preserve);
setenv("PATH", ENV_PATH, !preserve);
if (chdir(pw->pw_dir) < 0)
eprintf("chdir %s:", pw->pw_dir);
execlp(pw->pw_shell, pw->pw_shell, "-l", NULL);
weprintf("execlp %s:", pw->pw_shell);
return (errno == ENOENT) ? 127 : 126;
}