ubase/login.c

131 lines
2.4 KiB
C

/* See LICENSE file for copyright and license details. */
#include <sys/ioctl.h>
#include <sys/types.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>
#include "config.h"
#include "passwd.h"
#include "util.h"
static int dologin(struct passwd *, int);
static void
usage(void)
{
eprintf("usage: %s [-p] username\n", argv0);
}
/* Write utmp entry */
static void
writeutmp(const char *user, const char *tty)
{
struct utmp usr;
FILE *fp;
memset(&usr, 0, sizeof(usr));
usr.ut_type = USER_PROCESS;
usr.ut_pid = getpid();
strlcpy(usr.ut_user, user, sizeof(usr.ut_user));
strlcpy(usr.ut_line, tty, sizeof(usr.ut_line));
usr.ut_tv.tv_sec = time(NULL);
fp = fopen(UTMP_PATH, "a");
if (fp) {
if (fwrite(&usr, sizeof(usr), 1, fp) != 1)
if (ferror(fp))
weprintf("%s: write error:", UTMP_PATH);
fclose(fp);
} else {
weprintf("fopen %s:", UTMP_PATH);
}
}
int
main(int argc, char *argv[])
{
struct passwd *pw;
char *pass, *user;
char *tty;
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;
user = argv[0];
pw = getpwnam(user);
if (errno)
eprintf("getpwnam: %s:", user);
else if (!pw)
eprintf("who are you?\n");
uid = pw->pw_uid;
gid = pw->pw_gid;
/* Flush pending input */
ioctl(STDIN_FILENO, TCFLSH, (void *)0);
pass = getpass("Password: "); putchar('\n');
if (!pass)
eprintf("getpass:");
if (pw_check(pw, pass) <= 0)
exit(EXIT_FAILURE);
tty = ttyname(STDIN_FILENO);
if (!tty)
eprintf("ttyname:");
writeutmp(user, tty);
if (initgroups(user, 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)
{
char *shell = pw->pw_shell[0] == '\0' ? "/bin/sh" : pw->pw_shell;
if (preserve == 0)
clearenv();
setenv("HOME", pw->pw_dir, 1);
setenv("SHELL", shell, 1);
setenv("USER", pw->pw_name, 1);
setenv("LOGNAME", pw->pw_name, 1);
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;
}