/* 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 Mi¶kiewicz * - 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 tarball for details. * */ #include "libbb.h" #include #if ENABLE_FEATURE_UTMP #include #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 */ #define SYSV_STYLE /* select System V style getty */ #include #include #if ENABLE_FEATURE_WTMP extern void updwtmp(const char *filename, const struct utmp *ut); static void update_utmp(const char *line); #endif #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 #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 FIRST_SPEED 0 /* Storage for command-line options. */ #define MAX_SPEED 10 /* max. nr. of baud rates */ 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 */ }; static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:wn"; #define F_INITSTRING (1<<0) /* initstring is set */ #define F_LOCAL (1<<1) /* force local */ #define F_FAKEHOST (1<<2) /* force fakehost */ #define F_CUSTISSUE (1<<3) /* give alternative issue file */ #define F_RTSCTS (1<<4) /* enable RTS/CTS flow control */ #define F_ISSUE (1<<5) /* display /etc/issue */ #define F_LOGIN (1<<6) /* non-default login program */ #define F_PARSE (1<<7) /* process modem status messages */ #define F_TIMEOUT (1<<8) /* time out */ #define F_WAITCRLF (1<<9) /* wait for CR or LF */ #define F_NOPROMPT (1<<10) /* don't ask for login name! */ /* 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 */ #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 }; /* The following is used for understandable diagnostics. */ /* Fake hostname for ut_host specified on command line. */ static char *fakehost = NULL; /* ... */ #ifdef DEBUGGING #define debug(s) fprintf(dbf,s); fflush(dbf) #define DEBUGTERM "/dev/ttyp0" static FILE *dbf; #else #define debug(s) /* nothing */ #endif /* bcode - convert speed string to speed code; return 0 on failure */ static int bcode(const char *s) { int r; unsigned value = bb_strtou(s, NULL, 10); if (errno) { return -1; } r = tty_value_to_baud(value); if (r > 0) { return r; } return 0; } /* parse_speeds - parse alternate baud rates */ static void parse_speeds(struct options *op, char *arg) { char *cp; debug("entered parse_speeds\n"); for (cp = strtok(arg, ","); cp != 0; cp = strtok((char *) 0, ",")) { if ((op->speeds[op->numspeed++] = bcode(cp)) <= 0) bb_error_msg_and_die("bad speed: %s", cp); if (op->numspeed > MAX_SPEED) bb_error_msg_and_die("too many alternate speeds"); } debug("exiting parsespeeds\n"); } /* parse_args - parse command-line arguments */ static void parse_args(int argc, char **argv, struct options *op) { char *ts; op->flags = getopt32(argv, opt_string, &(op->initstring), &fakehost, &(op->issue), &(op->login), &ts); if (op->flags & F_INITSTRING) { const char *p = op->initstring; char *q; op->initstring = q = xstrdup(op->initstring); /* 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; /* revert flag show /etc/issue */ if (op->flags & F_TIMEOUT) { op->timeout = xatoul_range(ts, 1, INT_MAX); } argv += optind; argc -= optind; debug("after getopt loop\n"); if (argc < 2) /* check parameter count */ bb_show_usage(); /* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */ if (isdigit(argv[0][0])) { /* a number first, assume it's a speed (BSD style) */ parse_speeds(op, argv[0]); /* baud rate(s) */ op->tty = argv[1]; /* tty name */ } else { op->tty = argv[0]; /* tty name */ parse_speeds(op, argv[1]); /* baud rate(s) */ } if (argv[2]) setenv("TERM", argv[2], 1); debug("exiting parseargs\n"); } /* open_tty - set up tty as standard { input, output, error } */ static void open_tty(const char *tty, struct termios *tp, int local) { int chdir_to_root = 0; /* Set up new standard input, unless we are given an already opened port. */ if (NOT_LONE_DASH(tty)) { struct stat st; int fd; /* Sanity checks... */ xchdir("/dev"); chdir_to_root = 1; xstat(tty, &st); if ((st.st_mode & S_IFMT) != S_IFCHR) bb_error_msg_and_die("%s: not a character device", tty); /* Open the tty as standard input. */ debug("open(2)\n"); fd = xopen(tty, O_RDWR | O_NONBLOCK); xdup2(fd, 0); while (fd > 2) close(fd--); } 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"); } /* Replace current standard output/error fd's with new ones */ 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. */ ioctl_or_perror_and_die(0, TCGETS, tp, "%s: TCGETS", tty); /* * It seems to be a terminal. Set proper protections and ownership. Mode * 0622 is suitable for SYSV <4 because /bin/login does not change * protections. SunOS 4 login will change the protections to 0620 (write * access for group tty) after the login has succeeded. */ #ifdef DEBIAN #warning Debian /dev/vcs[a]NN hack is deprecated and will be removed { /* tty to root.dialout 660 */ struct group *gr; int id; gr = getgrnam("dialout"); id = gr ? gr->gr_gid : 0; chown(tty, 0, id); chmod(tty, 0660); /* vcs,vcsa to root.sys 600 */ if (!strncmp(tty, "tty", 3) && isdigit(tty[3])) { char *vcs, *vcsa; vcs = xstrdup(tty); vcsa = xmalloc(strlen(tty) + 2); strcpy(vcs, "vcs"); strcpy(vcs + 3, tty + 3); strcpy(vcsa, "vcsa"); strcpy(vcsa + 4, tty + 3); gr = getgrnam("sys"); id = gr ? gr->gr_gid : 0; chown(vcs, 0, id); chmod(vcs, 0600); chown(vcsa, 0, id); chmod(vcs, 0600); free(vcs); free(vcsa); } } #else if (NOT_LONE_DASH(tty)) { chown(tty, 0, 0); /* 0:0 */ chmod(tty, 0622); /* crw--w--w- */ } #endif if (chdir_to_root) xchdir("/"); } /* 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); #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 ioctl(0, TCSETS, tp); /* go to blocking input even in local mode */ ndelay_off(0); 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 */ ioctl(0, TCSETS, 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 = read(0, buf, size_buf - 1); if (nread > 0) { buf[nread] = '\0'; for (bp = buf; bp < buf + nread; bp++) { if (isascii(*bp) && isdigit(*bp)) { speed = bcode(bp); if (speed) { 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; ioctl(0, TCSETS, tp); } /* next_speed - select next baud rate */ static void next_speed(struct termios *tp, struct options *op) { static int baud_index = FIRST_SPEED; /* current speed index */ baud_index = (baud_index + 1) % op->numspeed; tp->c_cflag &= ~CBAUD; tp->c_cflag |= op->speeds[baud_index]; ioctl(0, TCSETS, tp); } /* do_prompt - show login prompt, optionally preceded by /etc/issue contents */ static void do_prompt(struct options *op, struct termios *tp) { #ifdef ISSUE print_login_issue(op->issue, op->tty); #endif print_login_prompt(); } #ifdef HANDLE_ALLCAPS /* caps_lock - string contains upper case without lower case */ /* returns 1 if true, 0 if false */ static int caps_lock(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 failure, logname on success */ static char *get_logname(char *logname, unsigned size_logname, struct options *op, struct chardata *cp, struct termios *tp) { 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 */ "\210\240\210", /* no parity */ }; /* Initialize kill, erase, parity etc. (also after switching speeds). */ *cp = init_chardata; /* Flush pending input (esp. after parsing or switching the baud rate). */ sleep(1); ioctl(0, TCFLSH, TCIFLUSH); /* 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, tp); /* 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(0, &c, 1) < 1) { if (errno == EINTR || errno == EIO) exit(0); bb_perror_msg_and_die("%s: read", op->tty); } /* Do BREAK handling elsewhere. */ if (c == '\0' && op->numspeed > 1) return NULL; /* Do parity bit handling. */ ascval = c & 0177; if (c != ascval) { /* "parity" bit on ? */ bits = 1; mask = 1; while (mask & 0177) { if (mask & ascval) bits++; /* count "1" bits */ mask <<= 1; } /* ... |= 2 - even, 1 - odd */ cp->parity |= 2 - (bits & 1); } /* Do erase, kill and end-of-line processing. */ switch (ascval) { case CR: case NL: *bp = '\0'; /* terminate logname */ cp->eol = ascval; /* set end-of-line char */ break; case BS: case DEL: case '#': cp->erase = ascval; /* set erase character */ if (bp > logname) { write(1, erase[cp->parity], 3); bp--; } break; case CTL('U'): case '@': cp->kill = ascval; /* set kill character */ while (bp > logname) { write(1, erase[cp->parity], 3); bp--; } break; case CTL('D'): exit(0); default: if (!isascii(ascval) || !isprint(ascval)) { /* ignore garbage characters */ } else if (bp - logname >= size_logname - 1) { bb_error_msg_and_die("%s: input overrun", op->tty); } else { write(1, &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 = caps_lock(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 */ 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; 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 */ ioctl_or_perror_and_die(0, TCSETS, tp, "%s: TCSETS", op->tty); } #ifdef SYSV_STYLE #if ENABLE_FEATURE_UTMP /* update_utmp - update our utmp entry */ static void update_utmp(const char *line) { struct utmp ut; struct utmp *utp; time_t t; int mypid = getpid(); /* * 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. */ if (access(_PATH_UTMP, R_OK|W_OK) == -1) { close(creat(_PATH_UTMP, 0664)); } utmpname(_PATH_UTMP); setutent(); while ((utp = getutent()) && !(utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid)) /* nothing */; if (utp) { memcpy(&ut, utp, sizeof(ut)); } else { /* some inits don't initialize utmp... */ memset(&ut, 0, sizeof(ut)); safe_strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id)); } /* endutent(); */ 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)); time(&t); ut.ut_time = t; ut.ut_type = LOGIN_PROCESS; ut.ut_pid = mypid; pututline(&ut); endutent(); #if ENABLE_FEATURE_WTMP if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) close(creat(bb_path_wtmp_file, 0664)); updwtmp(bb_path_wtmp_file, &ut); #endif } #endif /* CONFIG_FEATURE_UTMP */ #endif /* SYSV_STYLE */ int getty_main(int argc, char **argv); int getty_main(int argc, char **argv) { int nullfd; char *logname = NULL; /* 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 = { 0, /* show /etc/issue (SYSV_STYLE) */ 0, /* no timeout */ _PATH_LOGIN, /* default login program */ "tty1", /* default tty line */ "", /* modem init string */ #ifdef ISSUE ISSUE, /* default issue file */ #else NULL, #endif 0, /* no baud rates known yet */ }; /* Already too late because of theoretical * possibility of getty --help somehow triggered * inadvertently before we reach this. Oh well. */ logmode = LOGMODE_NONE; setsid(); nullfd = xopen(bb_dev_null, O_RDWR); /* dup2(nullfd, 0); - no, because of possible "getty - 9600" */ /* open_tty() will take care of fd# 0 anyway */ dup2(nullfd, 1); dup2(nullfd, 2); while (nullfd > 2) close(nullfd--); /* We want special flavor of error_msg_and_die */ die_sleep = 10; msg_eol = "\r\n"; openlog(applet_name, LOG_PID, LOG_AUTH); logmode = LOGMODE_BOTH; #ifdef DEBUGGING dbf = xfopen(DEBUGTERM, "w"); { int i; for (i = 1; i < argc; i++) { debug(argv[i]); debug("\n"); } } #endif /* Parse command-line arguments. */ parse_args(argc, argv, &options); #ifdef SYSV_STYLE #if ENABLE_FEATURE_UTMP /* Update the utmp file. */ update_utmp(options.tty); #endif #endif debug("calling open_tty\n"); /* Open the tty as standard { input, output, error }. */ open_tty(options.tty, &termios, options.flags & F_LOCAL); #ifdef __linux__ { int iv; iv = getpid(); ioctl(0, TIOCSPGRP, &iv); } #endif /* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */ debug("calling termios_init\n"); termios_init(&termios, options.speeds[FIRST_SPEED], &options); /* write the modem init string and DON'T flush the buffers */ if (options.flags & F_INITSTRING) { debug("writing init string\n"); write(1, options.initstring, strlen(options.initstring)); } if (!(options.flags & F_LOCAL)) { /* go to blocking write mode unless -L is specified */ ndelay_off(1); } /* Optionally detect the baud rate from the modem status message. */ debug("before autobaud\n"); if (options.flags & F_PARSE) auto_baud(bb_common_bufsiz1, sizeof(bb_common_bufsiz1), &termios); /* Set the optional timer. */ if (options.timeout) alarm(options.timeout); /* optionally wait for CR or LF before writing /etc/issue */ if (options.flags & F_WAITCRLF) { char ch; debug("waiting for cr-lf\n"); while (read(0, &ch, 1) == 1) { ch &= 0x7f; /* strip "parity bit" */ #ifdef DEBUGGING fprintf(dbf, "read %c\n", ch); #endif if (ch == '\n' || ch == '\r') break; } } chardata = init_chardata; if (!(options.flags & F_NOPROMPT)) { /* Read the login name. */ debug("reading login name\n"); logname = get_logname(bb_common_bufsiz1, sizeof(bb_common_bufsiz1), &options, &chardata, &termios); while (logname == NULL) next_speed(&termios, &options); } /* Disable timer. */ if (options.timeout) alarm(0); /* Finalize the termios settings. */ termios_final(&options, &termios, &chardata); /* Now the newline character should be properly written. */ write(1, "\n", 1); /* Let the login program take care of password validation. */ execl(options.login, options.login, "--", logname, (char *) 0); bb_error_msg_and_die("%s: can't exec %s", options.tty, options.login); }