131 lines
2.3 KiB
C
131 lines
2.3 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <errno.h>
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#include <grp.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <utmp.h>
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#include "config.h"
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#include "passwd.h"
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#include "util.h"
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/* Write utmp entry */
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static void
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writeutmp(const char *user, const char *tty)
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{
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struct utmp usr;
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FILE *fp;
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memset(&usr, 0, sizeof(usr));
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usr.ut_type = USER_PROCESS;
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usr.ut_pid = getpid();
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strlcpy(usr.ut_user, user, sizeof(usr.ut_user));
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strlcpy(usr.ut_line, tty, sizeof(usr.ut_line));
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usr.ut_tv.tv_sec = time(NULL);
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fp = fopen(UTMP_PATH, "a");
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if (fp) {
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if (fwrite(&usr, sizeof(usr), 1, fp) != 1)
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if (ferror(fp))
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weprintf("%s: write error:", UTMP_PATH);
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fclose(fp);
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} else {
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weprintf("fopen %s:", UTMP_PATH);
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}
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}
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static int
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dologin(struct passwd *pw, int preserve)
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{
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char *shell = pw->pw_shell[0] == '\0' ? "/bin/sh" : pw->pw_shell;
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if (preserve == 0)
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clearenv();
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setenv("HOME", pw->pw_dir, 1);
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setenv("SHELL", shell, 1);
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setenv("USER", pw->pw_name, 1);
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setenv("LOGNAME", pw->pw_name, 1);
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setenv("PATH", ENV_PATH, 1);
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if (chdir(pw->pw_dir) < 0)
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eprintf("chdir %s:", pw->pw_dir);
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execlp(shell, shell, "-l", NULL);
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weprintf("execlp %s:", shell);
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return (errno == ENOENT) ? 127 : 126;
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}
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static void
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usage(void)
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{
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eprintf("usage: %s [-p] username\n", argv0);
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}
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int
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main(int argc, char *argv[])
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{
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struct passwd *pw;
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char *pass, *user;
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char *tty;
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uid_t uid;
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gid_t gid;
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int pflag = 0;
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ARGBEGIN {
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case 'p':
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pflag = 1;
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break;
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default:
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usage();
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} ARGEND;
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if (argc < 1)
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usage();
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if (isatty(0) == 0 || isatty(1) == 0 || isatty(2) == 0)
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eprintf("no tty");
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user = argv[0];
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errno = 0;
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pw = getpwnam(user);
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if (!pw) {
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if (errno)
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eprintf("getpwnam %s:", user);
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else
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eprintf("who are you?\n");
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}
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uid = pw->pw_uid;
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gid = pw->pw_gid;
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/* Flush pending input */
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ioctl(0, TCFLSH, (void *)0);
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pass = getpass("Password: ");
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if (!pass)
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eprintf("getpass:");
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if (pw_check(pw, pass) <= 0)
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exit(1);
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tty = ttyname(0);
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if (!tty)
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eprintf("ttyname:");
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writeutmp(user, tty);
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if (initgroups(user, gid) < 0)
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eprintf("initgroups:");
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if (setgid(gid) < 0)
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eprintf("setgid:");
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if (setuid(uid) < 0)
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eprintf("setuid:");
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return dologin(pw, pflag);
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}
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