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Diffstat (limited to 'loginutils/getty.c')
| -rw-r--r-- | loginutils/getty.c | 777 |
1 files changed, 777 insertions, 0 deletions
diff --git a/loginutils/getty.c b/loginutils/getty.c new file mode 100644 index 0000000..0f53688 --- /dev/null +++ b/loginutils/getty.c @@ -0,0 +1,777 @@ +/* vi: set sw=4 ts=4: */ +/* agetty.c - another getty program for Linux. By W. Z. Venema 1989 + * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk> + * 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 <ear@usfirst.org> - 12/28/95 + * + * 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org> + * - added Native Language Support + * + * 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net> + * - enable hardware flow control before displaying /etc/issue + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. + */ + +#include "libbb.h" +#include <syslog.h> + +#if ENABLE_FEATURE_UTMP +#include <utmp.h> /* updwtmp() */ +#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 <sys/utsname.h> +#include <time.h> +#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); + 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) { + const char *p = op->initstring; + char *q; + + op->initstring = q = xstrdup(p); + /* copy optarg into op->initstring decoding \ddd + octal codes into chars */ + while (*p) { + if (*p == '\\') { + p++; + *q++ = bb_process_escape_sequence(&p); + } else { + *q++ = *p++; + } + } + *q = '\0'; + } + 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); + +// TODO: if applet_name is set to "getty: TTY", bb_error_msg's get simpler! +// grep for "%s:" + + 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 ((st.st_mode & S_IFMT) != S_IFCHR) +// bb_error_msg_and_die("%s: not a character device", tty); + + 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) +{ + /* + * 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. + */ +#ifdef __linux__ + /* flush input and output queues, important for modems! */ + ioctl(0, TCFLSH, TCIOFLUSH); /* tcflush(0, TCIOFLUSH)? - same */ +#endif + + tp->c_cflag = CS8 | HUPCL | CREAD | speed; + if (op->flags & F_LOCAL) + tp->c_cflag |= CLOCAL; + + tp->c_iflag = tp->c_lflag = tp->c_line = 0; + tp->c_oflag = OPOST | ONLCR; + tp->c_cc[VMIN] = 1; + tp->c_cc[VTIME] = 0; + + /* 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: + * + * <junk><number><junk> + * + * 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) { + tp->c_cflag &= ~CBAUD; + tp->c_cflag |= 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); + ioctl(0, TCFLSH, TCIFLUSH); /* tcflush(0, TCIOFLUSH)? - same */ + + /* 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. */ + if (read(STDIN_FILENO, &c, 1) < 1) { + if (errno == EINTR || errno == EIO) + exit(EXIT_SUCCESS); + bb_perror_msg_and_die("%s: read", op->tty); + } + + /* 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 (!isascii(ascval) || !isprint(ascval)) { + /* ignore garbage characters */ + } else if ((int)(bp - logname) >= size_logname - 1) { + bb_error_msg_and_die("%s: input overrun", op->tty); + } 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; + tp->c_cc[VSWTC] = DEF_SWITCH; /* default switch character */ + + /* 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 */ + /* It's tcsetattr_stdin_TCSANOW() + error check */ + ioctl_or_perror_and_die(0, TCSETS, tp, "%s: TCSETS", op->tty); +} + +#if ENABLE_FEATURE_UTMP +static void touch(const char *filename) +{ + if (access(filename, R_OK | W_OK) == -1) + close(open(filename, O_WRONLY | O_CREAT, 0664)); +} + +/* update_utmp - update our utmp entry */ +static void update_utmp(const char *line, char *fakehost) +{ + struct utmp ut; + struct utmp *utp; + int mypid = getpid(); + + /* In case we won't find an entry below... */ + memset(&ut, 0, sizeof(ut)); + safe_strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id)); + + /* + * The utmp file holds miscellaneous information about things started by + * /sbin/init and other system-related events. Our purpose is to update + * the utmp entry for the current process, in particular the process type + * and the tty line we are listening to. Return successfully only if the + * utmp file can be opened for update, and if we are able to find our + * entry in the utmp file. + */ + touch(_PATH_UTMP); + + utmpname(_PATH_UTMP); + setutent(); + while ((utp = getutent()) != NULL) { + if (utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid) { + memcpy(&ut, utp, sizeof(ut)); + break; + } + } + + strcpy(ut.ut_user, "LOGIN"); + safe_strncpy(ut.ut_line, line, sizeof(ut.ut_line)); + if (fakehost) + safe_strncpy(ut.ut_host, fakehost, sizeof(ut.ut_host)); + ut.ut_tv.tv_sec = time(NULL); + ut.ut_type = LOGIN_PROCESS; + ut.ut_pid = mypid; + + pututline(&ut); + endutent(); + +#if ENABLE_FEATURE_WTMP + touch(bb_path_wtmp_file); + updwtmp(bb_path_wtmp_file, &ut); +#endif +} +#endif /* CONFIG_FEATURE_UTMP */ + +int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int getty_main(int argc UNUSED_PARAM, char **argv) +{ + int n; + 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. + */ + /* tcgetattr() + error check */ + ioctl_or_perror_and_die(0, TCGETS, &termios, "%s: TCGETS", options.tty); + +#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, getpid()); +#endif + +#if ENABLE_FEATURE_UTMP + /* Update the utmp file. This tty is ours now! */ + update_utmp(options.tty, fakehost); +#endif + + /* 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_write(STDOUT_FILENO, options.initstring, strlen(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; + termios.c_cflag &= ~CBAUD; + termios.c_cflag |= 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("%s: can't exec %s", options.tty, options.login); +} |