/* vi: set sw=4 ts=4: */ /* agetty.c - another getty program for Linux. By W. Z. Venema 1989 * Ported to Linux by Peter Orbaek * This program is freely distributable. The entire man-page used to * be here. Now read the real man-page agetty.8 instead. * * option added by Eric Rasmussen - 12/28/95 * * 1999-02-22 Arkadiusz Mickiewicz * - added Native Language Support * * 1999-05-05 Thorsten Kranzkowski * - enable hardware flow control before displaying /etc/issue * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ #include "libbb.h" #include #if ENABLE_FEATURE_UTMP # include /* LOGIN_PROCESS */ #endif #ifndef IUCLC # define IUCLC 0 #endif /* * Some heuristics to find out what environment we are in: if it is not * System V, assume it is SunOS 4. */ #ifdef LOGIN_PROCESS /* defined in System V utmp.h */ #include #else /* if !sysV style, wtmp/utmp code is off */ #undef ENABLE_FEATURE_UTMP #undef ENABLE_FEATURE_WTMP #define ENABLE_FEATURE_UTMP 0 #define ENABLE_FEATURE_WTMP 0 #endif /* LOGIN_PROCESS */ /* * Things you may want to modify. * * You may disagree with the default line-editing etc. characters defined * below. Note, however, that DEL cannot be used for interrupt generation * and for line editing at the same time. */ /* I doubt there are systems which still need this */ #undef HANDLE_ALLCAPS #undef ANCIENT_BS_KILL_CHARS #define _PATH_LOGIN "/bin/login" /* If ISSUE is not defined, getty will never display the contents of the * /etc/issue file. You will not want to spit out large "issue" files at the * wrong baud rate. */ #define ISSUE "/etc/issue" /* displayed before the login prompt */ /* Some shorthands for control characters. */ #define CTL(x) ((x) ^ 0100) /* Assumes ASCII dialect */ #define CR CTL('M') /* carriage return */ #define NL CTL('J') /* line feed */ #define BS CTL('H') /* back space */ #define DEL CTL('?') /* delete */ /* Defaults for line-editing etc. characters; you may want to change this. */ #define DEF_ERASE DEL /* default erase character */ #define DEF_INTR CTL('C') /* default interrupt character */ #define DEF_QUIT CTL('\\') /* default quit char */ #define DEF_KILL CTL('U') /* default kill char */ #define DEF_EOF CTL('D') /* default EOF char */ #define DEF_EOL '\n' #define DEF_SWITCH 0 /* default switch char */ /* * When multiple baud rates are specified on the command line, the first one * we will try is the first one specified. */ #define MAX_SPEED 10 /* max. nr. of baud rates */ /* Storage for command-line options. */ struct options { int flags; /* toggle switches, see below */ unsigned timeout; /* time-out period */ const char *login; /* login program */ const char *tty; /* name of tty */ const char *initstring; /* modem init string */ const char *issue; /* alternative issue file */ int numspeed; /* number of baud rates to try */ int speeds[MAX_SPEED]; /* baud rates to be tried */ }; /* Storage for things detected while the login name was read. */ struct chardata { unsigned char erase; /* erase character */ unsigned char kill; /* kill character */ unsigned char eol; /* end-of-line character */ unsigned char parity; /* what parity did we see */ /* (parity & 1): saw odd parity char with 7th bit set */ /* (parity & 2): saw even parity char with 7th bit set */ /* parity == 0: probably 7-bit, space parity? */ /* parity == 1: probably 7-bit, odd parity? */ /* parity == 2: probably 7-bit, even parity? */ /* parity == 3: definitely 8 bit, no parity! */ /* Hmm... with any value of "parity" 8 bit, no parity is possible */ #ifdef HANDLE_ALLCAPS unsigned char capslock; /* upper case without lower case */ #endif }; /* Initial values for the above. */ static const struct chardata init_chardata = { DEF_ERASE, /* default erase character */ DEF_KILL, /* default kill character */ 13, /* default eol char */ 0, /* space parity */ #ifdef HANDLE_ALLCAPS 0, /* no capslock */ #endif }; static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:wn"; #define F_INITSTRING (1 << 0) /* -I initstring is set */ #define F_LOCAL (1 << 1) /* -L force local */ #define F_FAKEHOST (1 << 2) /* -H fake hostname */ #define F_CUSTISSUE (1 << 3) /* -f give alternative issue file */ #define F_RTSCTS (1 << 4) /* -h enable RTS/CTS flow control */ #define F_ISSUE (1 << 5) /* -i display /etc/issue */ #define F_LOGIN (1 << 6) /* -l non-default login program */ #define F_PARSE (1 << 7) /* -m process modem status messages */ #define F_TIMEOUT (1 << 8) /* -t time out */ #define F_WAITCRLF (1 << 9) /* -w wait for CR or LF */ #define F_NOPROMPT (1 << 10) /* -n don't ask for login name */ #define line_buf bb_common_bufsiz1 /* The following is used for understandable diagnostics. */ #ifdef DEBUGGING static FILE *dbf; #define DEBUGTERM "/dev/ttyp0" #define debug(...) do { fprintf(dbf, __VA_ARGS__); fflush(dbf); } while (0) #else #define debug(...) ((void)0) #endif /* bcode - convert speed string to speed code; return <= 0 on failure */ static int bcode(const char *s) { int value = bb_strtou(s, NULL, 10); /* yes, int is intended! */ if (value < 0) /* bad terminating char, overflow, etc */ return value; return tty_value_to_baud(value); } /* parse_speeds - parse alternate baud rates */ static void parse_speeds(struct options *op, char *arg) { char *cp; /* NB: at least one iteration is always done */ debug("entered parse_speeds\n"); while ((cp = strsep(&arg, ",")) != NULL) { op->speeds[op->numspeed] = bcode(cp); if (op->speeds[op->numspeed] < 0) bb_error_msg_and_die("bad speed: %s", cp); /* note: arg "0" turns into speed B0 */ op->numspeed++; if (op->numspeed > MAX_SPEED) bb_error_msg_and_die("too many alternate speeds"); } debug("exiting parse_speeds\n"); } /* parse_args - parse command-line arguments */ static void parse_args(char **argv, struct options *op, char **fakehost_p) { char *ts; opt_complementary = "-2:t+"; /* at least 2 args; -t N */ op->flags = getopt32(argv, opt_string, &(op->initstring), fakehost_p, &(op->issue), &(op->login), &op->timeout); argv += optind; if (op->flags & F_INITSTRING) { op->initstring = xstrdup(op->initstring); /* decode \ddd octal codes into chars */ strcpy_and_process_escape_sequences((char*)op->initstring, op->initstring); } op->flags ^= F_ISSUE; /* invert flag "show /etc/issue" */ debug("after getopt\n"); /* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */ op->tty = argv[0]; /* tty name */ ts = argv[1]; /* baud rate(s) */ if (isdigit(argv[0][0])) { /* a number first, assume it's a speed (BSD style) */ op->tty = ts; /* tty name is in argv[1] */ ts = argv[0]; /* baud rate(s) */ } parse_speeds(op, ts); applet_name = xasprintf("getty: %s", op->tty); if (argv[2]) xsetenv("TERM", argv[2]); debug("exiting parse_args\n"); } /* open_tty - set up tty as standard { input, output, error } */ static void open_tty(const char *tty) { /* Set up new standard input, unless we are given an already opened port. */ if (NOT_LONE_DASH(tty)) { // struct stat st; // int cur_dir_fd; // int fd; /* Sanity checks... */ // cur_dir_fd = xopen(".", O_DIRECTORY | O_NONBLOCK); // xchdir("/dev"); // xstat(tty, &st); // if (!S_ISCHR(st.st_mode)) // bb_error_msg_and_die("not a character device"); if (tty[0] != '/') tty = xasprintf("/dev/%s", tty); /* will leak it */ /* Open the tty as standard input. */ debug("open(2)\n"); close(0); /*fd =*/ xopen(tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */ // /* Restore current directory */ // fchdir(cur_dir_fd); /* Open the tty as standard input, continued */ // xmove_fd(fd, 0); // /* fd is >= cur_dir_fd, and cur_dir_fd gets closed too here: */ // while (fd > 2) // close(fd--); /* Set proper protections and ownership. */ fchown(0, 0, 0); /* 0:0 */ fchmod(0, 0620); /* crw--w---- */ } else { /* * Standard input should already be connected to an open port. Make * sure it is open for read/write. */ if ((fcntl(0, F_GETFL) & O_RDWR) != O_RDWR) bb_error_msg_and_die("stdin is not open for read/write"); } } /* termios_init - initialize termios settings */ static void termios_init(struct termios *tp, int speed, struct options *op) { speed_t ispeed, ospeed; /* * Initial termios settings: 8-bit characters, raw-mode, blocking i/o. * Special characters are set after we have read the login name; all * reads will be done in raw mode anyway. Errors will be dealt with * later on. */ /* flush input and output queues, important for modems! */ tcflush(0, TCIOFLUSH); ispeed = ospeed = speed; if (speed == B0) { /* Speed was specified as "0" on command line. * Just leave it unchanged */ ispeed = cfgetispeed(tp); ospeed = cfgetospeed(tp); } tp->c_cflag = CS8 | HUPCL | CREAD; if (op->flags & F_LOCAL) tp->c_cflag |= CLOCAL; cfsetispeed(tp, ispeed); cfsetospeed(tp, ospeed); tp->c_iflag = tp->c_lflag = 0; tp->c_oflag = OPOST | ONLCR; tp->c_cc[VMIN] = 1; tp->c_cc[VTIME] = 0; #ifdef __linux__ tp->c_line = 0; #endif /* Optionally enable hardware flow control */ #ifdef CRTSCTS if (op->flags & F_RTSCTS) tp->c_cflag |= CRTSCTS; #endif tcsetattr_stdin_TCSANOW(tp); debug("term_io 2\n"); } /* auto_baud - extract baud rate from modem status message */ static void auto_baud(char *buf, unsigned size_buf, struct termios *tp) { int speed; int vmin; unsigned iflag; char *bp; int nread; /* * This works only if the modem produces its status code AFTER raising * the DCD line, and if the computer is fast enough to set the proper * baud rate before the message has gone by. We expect a message of the * following format: * * * * The number is interpreted as the baud rate of the incoming call. If the * modem does not tell us the baud rate within one second, we will keep * using the current baud rate. It is advisable to enable BREAK * processing (comma-separated list of baud rates) if the processing of * modem status messages is enabled. */ /* * Use 7-bit characters, don't block if input queue is empty. Errors will * be dealt with later on. */ iflag = tp->c_iflag; tp->c_iflag |= ISTRIP; /* enable 8th-bit stripping */ vmin = tp->c_cc[VMIN]; tp->c_cc[VMIN] = 0; /* don't block if queue empty */ tcsetattr_stdin_TCSANOW(tp); /* * Wait for a while, then read everything the modem has said so far and * try to extract the speed of the dial-in call. */ sleep(1); nread = safe_read(STDIN_FILENO, buf, size_buf - 1); if (nread > 0) { buf[nread] = '\0'; for (bp = buf; bp < buf + nread; bp++) { if (isdigit(*bp)) { speed = bcode(bp); if (speed > 0) cfsetspeed(tp, speed); break; } } } /* Restore terminal settings. Errors will be dealt with later on. */ tp->c_iflag = iflag; tp->c_cc[VMIN] = vmin; tcsetattr_stdin_TCSANOW(tp); } /* do_prompt - show login prompt, optionally preceded by /etc/issue contents */ static void do_prompt(struct options *op) { #ifdef ISSUE print_login_issue(op->issue, op->tty); #endif print_login_prompt(); } #ifdef HANDLE_ALLCAPS /* all_is_upcase - string contains upper case without lower case */ /* returns 1 if true, 0 if false */ static int all_is_upcase(const char *s) { while (*s) if (islower(*s++)) return 0; return 1; } #endif /* get_logname - get user name, establish parity, speed, erase, kill, eol; * return NULL on BREAK, logname on success */ static char *get_logname(char *logname, unsigned size_logname, struct options *op, struct chardata *cp) { char *bp; char c; /* input character, full eight bits */ char ascval; /* low 7 bits of input character */ int bits; /* # of "1" bits per character */ int mask; /* mask with 1 bit up */ static const char erase[][3] = {/* backspace-space-backspace */ "\010\040\010", /* space parity */ "\010\040\010", /* odd parity */ "\210\240\210", /* even parity */ "\010\040\010", /* 8 bit no parity */ }; /* NB: *cp is pre-initialized with init_chardata */ /* Flush pending input (esp. after parsing or switching the baud rate). */ sleep(1); tcflush(0, TCIOFLUSH); /* Prompt for and read a login name. */ logname[0] = '\0'; while (!logname[0]) { /* Write issue file and prompt, with "parity" bit == 0. */ do_prompt(op); /* Read name, watch for break, parity, erase, kill, end-of-line. */ bp = logname; cp->eol = '\0'; while (cp->eol == '\0') { /* Do not report trivial EINTR/EIO errors. */ errno = EINTR; /* make read of 0 bytes be silent too */ if (read(STDIN_FILENO, &c, 1) < 1) { if (errno == EINTR || errno == EIO) exit(EXIT_SUCCESS); bb_perror_msg_and_die(bb_msg_read_error); } /* BREAK. If we have speeds to try, * return NULL (will switch speeds and return here) */ if (c == '\0' && op->numspeed > 1) return NULL; /* Do parity bit handling. */ if (!(op->flags & F_LOCAL) && (c & 0x80)) { /* "parity" bit on? */ bits = 1; mask = 1; while (mask & 0x7f) { if (mask & c) bits++; /* count "1" bits */ mask <<= 1; } /* ... |= 2 - even, 1 - odd */ cp->parity |= 2 - (bits & 1); } /* Do erase, kill and end-of-line processing. */ ascval = c & 0x7f; switch (ascval) { case CR: case NL: *bp = '\0'; /* terminate logname */ cp->eol = ascval; /* set end-of-line char */ break; case BS: case DEL: #ifdef ANCIENT_BS_KILL_CHARS case '#': #endif cp->erase = ascval; /* set erase character */ if (bp > logname) { full_write(STDOUT_FILENO, erase[cp->parity], 3); bp--; } break; case CTL('U'): #ifdef ANCIENT_BS_KILL_CHARS case '@': #endif cp->kill = ascval; /* set kill character */ while (bp > logname) { full_write(STDOUT_FILENO, erase[cp->parity], 3); bp--; } break; case CTL('D'): exit(EXIT_SUCCESS); default: if (ascval < ' ') { /* ignore garbage characters */ } else if ((int)(bp - logname) >= size_logname - 1) { bb_error_msg_and_die("input overrun"); } else { full_write(STDOUT_FILENO, &c, 1); /* echo the character */ *bp++ = ascval; /* and store it */ } break; } } } /* Handle names with upper case and no lower case. */ #ifdef HANDLE_ALLCAPS cp->capslock = all_is_upcase(logname); if (cp->capslock) { for (bp = logname; *bp; bp++) if (isupper(*bp)) *bp = tolower(*bp); /* map name to lower case */ } #endif return logname; } /* termios_final - set the final tty mode bits */ static void termios_final(struct options *op, struct termios *tp, struct chardata *cp) { /* General terminal-independent stuff. */ tp->c_iflag |= IXON | IXOFF; /* 2-way flow control */ tp->c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE; /* no longer| ECHOCTL | ECHOPRT */ tp->c_oflag |= OPOST; /* tp->c_cflag = 0; */ tp->c_cc[VINTR] = DEF_INTR; /* default interrupt */ tp->c_cc[VQUIT] = DEF_QUIT; /* default quit */ tp->c_cc[VEOF] = DEF_EOF; /* default EOF character */ tp->c_cc[VEOL] = DEF_EOL; #ifdef VSWTC tp->c_cc[VSWTC] = DEF_SWITCH; /* default switch character */ #endif /* Account for special characters seen in input. */ if (cp->eol == CR) { tp->c_iflag |= ICRNL; /* map CR in input to NL */ tp->c_oflag |= ONLCR; /* map NL in output to CR-NL */ } tp->c_cc[VERASE] = cp->erase; /* set erase character */ tp->c_cc[VKILL] = cp->kill; /* set kill character */ /* Account for the presence or absence of parity bits in input. */ switch (cp->parity) { case 0: /* space (always 0) parity */ // I bet most people go here - they use only 7-bit chars in usernames.... break; case 1: /* odd parity */ tp->c_cflag |= PARODD; /* FALLTHROUGH */ case 2: /* even parity */ tp->c_cflag |= PARENB; tp->c_iflag |= INPCK | ISTRIP; /* FALLTHROUGH */ case (1 | 2): /* no parity bit */ tp->c_cflag &= ~CSIZE; tp->c_cflag |= CS7; // FIXME: wtf? case 3: we saw both even and odd 8-bit bytes - // it's probably some umlauts etc, but definitely NOT 7-bit!!! // Entire parity detection madness here just begs for deletion... break; } /* Account for upper case without lower case. */ #ifdef HANDLE_ALLCAPS if (cp->capslock) { tp->c_iflag |= IUCLC; tp->c_lflag |= XCASE; tp->c_oflag |= OLCUC; } #endif /* Optionally enable hardware flow control */ #ifdef CRTSCTS if (op->flags & F_RTSCTS) tp->c_cflag |= CRTSCTS; #endif /* Finally, make the new settings effective */ if (tcsetattr_stdin_TCSANOW(tp) < 0) bb_perror_msg_and_die("tcsetattr"); } int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int getty_main(int argc UNUSED_PARAM, char **argv) { int n; pid_t pid; char *fakehost = NULL; /* Fake hostname for ut_host */ char *logname; /* login name, given to /bin/login */ /* Merging these into "struct local" may _seem_ to reduce * parameter passing, but today's gcc will inline * statics which are called once anyway, so don't do that */ struct chardata chardata; /* set by get_logname() */ struct termios termios; /* terminal mode bits */ struct options options; chardata = init_chardata; memset(&options, 0, sizeof(options)); options.login = _PATH_LOGIN; /* default login program */ options.tty = "tty1"; /* default tty line */ options.initstring = ""; /* modem init string */ #ifdef ISSUE options.issue = ISSUE; /* default issue file */ #endif /* Parse command-line arguments. */ parse_args(argv, &options, &fakehost); logmode = LOGMODE_NONE; /* Create new session, lose controlling tty, if any */ /* docs/ctty.htm says: * "This is allowed only when the current process * is not a process group leader" - is this a problem? */ setsid(); /* close stdio, and stray descriptors, just in case */ n = xopen(bb_dev_null, O_RDWR); /* dup2(n, 0); - no, we need to handle "getty - 9600" too */ xdup2(n, 1); xdup2(n, 2); while (n > 2) close(n--); /* Logging. We want special flavor of error_msg_and_die */ die_sleep = 10; msg_eol = "\r\n"; /* most likely will internally use fd #3 in CLOEXEC mode: */ openlog(applet_name, LOG_PID, LOG_AUTH); logmode = LOGMODE_BOTH; #ifdef DEBUGGING dbf = xfopen_for_write(DEBUGTERM); for (n = 1; argv[n]; n++) { debug(argv[n]); debug("\n"); } #endif /* Open the tty as standard input, if it is not "-" */ /* If it's not "-" and not taken yet, it will become our ctty */ debug("calling open_tty\n"); open_tty(options.tty); ndelay_off(0); debug("duping\n"); xdup2(0, 1); xdup2(0, 2); /* * The following ioctl will fail if stdin is not a tty, but also when * there is noise on the modem control lines. In the latter case, the * common course of action is (1) fix your cables (2) give the modem more * time to properly reset after hanging up. SunOS users can achieve (2) * by patching the SunOS kernel variable "zsadtrlow" to a larger value; * 5 seconds seems to be a good value. */ if (tcgetattr(0, &termios) < 0) bb_perror_msg_and_die("tcgetattr"); pid = getpid(); #ifdef __linux__ // FIXME: do we need this? Otherwise "-" case seems to be broken... // /* Forcibly make fd 0 our controlling tty, even if another session // * has it as a ctty. (Another session loses ctty). */ // ioctl(0, TIOCSCTTY, (void*)1); /* Make ourself a foreground process group within our session */ tcsetpgrp(0, pid); #endif /* Update the utmp file. This tty is ours now! */ update_utmp(pid, LOGIN_PROCESS, options.tty, "LOGIN", fakehost); /* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */ debug("calling termios_init\n"); termios_init(&termios, options.speeds[0], &options); /* Write the modem init string and DON'T flush the buffers */ if (options.flags & F_INITSTRING) { debug("writing init string\n"); full_write1_str(options.initstring); } /* Optionally detect the baud rate from the modem status message */ debug("before autobaud\n"); if (options.flags & F_PARSE) auto_baud(line_buf, sizeof(line_buf), &termios); /* Set the optional timer */ alarm(options.timeout); /* if 0, alarm is not set */ /* Optionally wait for CR or LF before writing /etc/issue */ if (options.flags & F_WAITCRLF) { char ch; debug("waiting for cr-lf\n"); while (safe_read(STDIN_FILENO, &ch, 1) == 1) { debug("read %x\n", (unsigned char)ch); ch &= 0x7f; /* strip "parity bit" */ if (ch == '\n' || ch == '\r') break; } } logname = NULL; if (!(options.flags & F_NOPROMPT)) { /* NB:termios_init already set line speed * to options.speeds[0] */ int baud_index = 0; while (1) { /* Read the login name. */ debug("reading login name\n"); logname = get_logname(line_buf, sizeof(line_buf), &options, &chardata); if (logname) break; /* we are here only if options.numspeed > 1 */ baud_index = (baud_index + 1) % options.numspeed; cfsetispeed(&termios, options.speeds[baud_index]); cfsetospeed(&termios, options.speeds[baud_index]); tcsetattr_stdin_TCSANOW(&termios); } } /* Disable timer. */ alarm(0); /* Finalize the termios settings. */ termios_final(&options, &termios, &chardata); /* Now the newline character should be properly written. */ full_write(STDOUT_FILENO, "\n", 1); /* Let the login program take care of password validation. */ /* We use PATH because we trust that root doesn't set "bad" PATH, * and getty is not suid-root applet. */ /* With -n, logname == NULL, and login will ask for username instead */ BB_EXECLP(options.login, options.login, "--", logname, NULL); bb_error_msg_and_die("can't execute '%s'", options.login); }