diff options
Diffstat (limited to 'loginutils')
-rw-r--r-- | loginutils/getty.c | 392 |
1 files changed, 165 insertions, 227 deletions
diff --git a/loginutils/getty.c b/loginutils/getty.c index d32d189..590a05d 100644 --- a/loginutils/getty.c +++ b/loginutils/getty.c @@ -33,7 +33,6 @@ #include <time.h> #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 */ @@ -47,6 +46,7 @@ static void update_utmp(const char *line); /* I doubt there are systems which still need this */ #undef HANDLE_ALLCAPS +#undef ANCIENT_BS_KILL_CHARS #define _PATH_LOGIN "/bin/login" @@ -76,36 +76,20 @@ static void update_utmp(const char *line); * 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 */ +/* 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 */ + 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 */ @@ -117,6 +101,7 @@ struct chardata { #endif }; + /* Initial values for the above. */ static const struct chardata init_chardata = { DEF_ERASE, /* default erase character */ @@ -128,12 +113,25 @@ static const struct chardata init_chardata = { #endif }; -/* The following is used for understandable diagnostics. */ +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 force fakehost */ +#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! */ + /* Fake hostname for ut_host specified on command line. */ static char *fakehost = NULL; +#define line_buf bb_common_bufsiz1 -/* ... */ +/* The following is used for understandable diagnostics. */ #ifdef DEBUGGING #define debug(s) fprintf(dbf,s); fflush(dbf) #define DEBUGTERM "/dev/ttyp0" @@ -158,14 +156,14 @@ static int bcode(const char *s) return 0; } - /* 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"); - for (cp = strtok(arg, ","); cp != 0; cp = strtok((char *) 0, ",")) { + 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); @@ -173,18 +171,19 @@ static void parse_speeds(struct options *op, char *arg) if (op->numspeed > MAX_SPEED) bb_error_msg_and_die("too many alternate speeds"); } - debug("exiting parsespeeds\n"); + debug("exiting parse_speeds\n"); } - /* parse_args - parse command-line arguments */ -static void parse_args(int argc, char **argv, struct options *op) +static void parse_args(char **argv, struct options *op) { char *ts; + opt_complementary = "-2"; /* at least 2 args */ op->flags = getopt32(argv, opt_string, &(op->initstring), &fakehost, &(op->issue), &(op->login), &ts); + argv += optind; if (op->flags & F_INITSTRING) { const char *p = op->initstring; char *q; @@ -202,45 +201,40 @@ static void parse_args(int argc, char **argv, struct options *op) } *q = '\0'; } - op->flags ^= F_ISSUE; /* revert flag show /etc/issue */ + op->flags ^= F_ISSUE; /* invert flag show /etc/issue */ if (op->flags & F_TIMEOUT) { - op->timeout = xatoul_range(ts, 1, INT_MAX); + op->timeout = xatoi_u(ts); } - argv += optind; - argc -= optind; - debug("after getopt loop\n"); - if (argc < 2) /* check parameter count */ - bb_show_usage(); + 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) */ - 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) */ + op->tty = ts; /* tty name is in argv[1] */ + ts = argv[0]; /* baud rate(s) */ } + parse_speeds(op, ts); if (argv[2]) setenv("TERM", argv[2], 1); - debug("exiting parseargs\n"); + debug("exiting parse_args\n"); } /* open_tty - set up tty as standard { input, output, error } */ -static void open_tty(const char *tty, struct termios *tp, int local) +static void open_tty(const char *tty) { - 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 cur_dir_fd; int fd; /* Sanity checks... */ + cur_dir_fd = xopen(".", O_DIRECTORY | O_NONBLOCK); 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); @@ -248,9 +242,23 @@ static void open_tty(const char *tty, struct termios *tp, int local) /* Open the tty as standard input. */ debug("open(2)\n"); fd = xopen(tty, O_RDWR | O_NONBLOCK); + + /* Restore current directory */ + fchdir(cur_dir_fd); + + /* Open the tty as standard input, continued */ xdup2(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. 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. + */ + fchown(0, 0, 0); /* 0:0 */ + fchmod(0, 0622); /* crw--w--w- */ } else { /* * Standard input should already be connected to an open port. Make @@ -259,71 +267,6 @@ static void open_tty(const char *tty, struct termios *tp, int local) 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 */ @@ -351,17 +294,13 @@ static void termios_init(struct termios *tp, int speed, struct options *op) tp->c_cc[VTIME] = 0; /* Optionally enable hardware flow control */ - -#ifdef CRTSCTS +#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"); } @@ -393,26 +332,24 @@ static void auto_baud(char *buf, unsigned size_buf, struct termios *tp) * 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 */ + 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); + nread = safe_read(0, buf, size_buf - 1); if (nread > 0) { buf[nread] = '\0'; for (bp = buf; bp < buf + nread; bp++) { - if (isascii(*bp) && isdigit(*bp)) { + if (isdigit(*bp)) { speed = bcode(bp); - if (speed) { + if (speed > 0) { tp->c_cflag &= ~CBAUD; tp->c_cflag |= speed; } @@ -420,25 +357,13 @@ static void auto_baud(char *buf, unsigned size_buf, struct termios *tp) } } } - /* Restore terminal settings. Errors will be dealt with later on. */ + /* 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) { @@ -449,9 +374,9 @@ static void do_prompt(struct options *op, struct termios *tp) } #ifdef HANDLE_ALLCAPS -/* caps_lock - string contains upper case without lower case */ +/* all_is_upcase - string contains upper case without lower case */ /* returns 1 if true, 0 if false */ -static int caps_lock(const char *s) +static int all_is_upcase(const char *s) { while (*s) if (islower(*s++)) @@ -460,8 +385,8 @@ static int caps_lock(const char *s) } #endif -/* get_logname - get user name, establish parity, speed, erase, kill, eol */ -/* return NULL on failure, logname on success */ +/* 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, struct termios *tp) { @@ -477,26 +402,19 @@ static char *get_logname(char *logname, unsigned size_logname, "\210\240\210", /* no parity */ }; - /* Initialize kill, erase, parity etc. (also after switching speeds). */ - - *cp = init_chardata; + /* 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); /* 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') { @@ -508,7 +426,8 @@ static char *get_logname(char *logname, unsigned size_logname, bb_perror_msg_and_die("%s: read", op->tty); } - /* Do BREAK handling elsewhere. */ + /* BREAK. If we have speeds to try, + * return NULL (will switch speeds and return here) */ if (c == '\0' && op->numspeed > 1) return NULL; @@ -535,18 +454,22 @@ static char *get_logname(char *logname, unsigned size_logname, break; case BS: case DEL: +#ifdef ANCIENT_BS_KILL_CHARS case '#': +#endif cp->erase = ascval; /* set erase character */ if (bp > logname) { - write(1, erase[cp->parity], 3); + full_write(1, 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) { - write(1, erase[cp->parity], 3); + full_write(1, erase[cp->parity], 3); bp--; } break; @@ -558,7 +481,7 @@ static char *get_logname(char *logname, unsigned size_logname, } 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 */ + full_write(1, &c, 1); /* echo the character */ *bp++ = ascval; /* and store it */ } break; @@ -568,7 +491,7 @@ static char *get_logname(char *logname, unsigned size_logname, /* Handle names with upper case and no lower case. */ #ifdef HANDLE_ALLCAPS - cp->capslock = caps_lock(logname); + cp->capslock = all_is_upcase(logname); if (cp->capslock) { for (bp = logname; *bp; bp++) if (isupper(*bp)) @@ -641,7 +564,6 @@ static void termios_final(struct options *op, struct termios *tp, struct chardat 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 */ @@ -666,17 +588,16 @@ static void update_utmp(const char *line) utmpname(_PATH_UTMP); setutent(); while ((utp = getutent()) - && !(utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid)) - /* nothing */; + && !(utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid) + ) { + continue; + } - if (utp) { + /* some inits don't initialize utmp... */ + memset(&ut, 0, sizeof(ut)); + safe_strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id)); + 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)); @@ -700,42 +621,43 @@ static void update_utmp(const char *line) #endif /* CONFIG_FEATURE_UTMP */ #endif /* SYSV_STYLE */ - int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int getty_main(int argc, char **argv) { - int nullfd; - char *logname = NULL; /* login name, given to /bin/login */ + int n; + 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 = { - 0, /* show /etc/issue (SYSV_STYLE) */ - 0, /* no timeout */ - _PATH_LOGIN, /* default login program */ - "tty1", /* default tty line */ - "", /* modem init string */ + struct termios termios; /* terminal mode bits */ + struct options options; + + 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 - ISSUE, /* default issue file */ -#else - NULL, + options.issue = ISSUE; /* default issue file */ #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; + + /* 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(); - 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--); + + n = xopen(bb_dev_null, O_RDWR); + /* dup2(n, 0); - no, because of possible "getty - 9600" */ + dup2(n, 1); + dup2(n, 2); + while (n > 2) + close(n--); /* We want special flavor of error_msg_and_die */ die_sleep = 10; msg_eol = "\r\n"; @@ -744,69 +666,74 @@ int getty_main(int argc, char **argv) #ifdef DEBUGGING dbf = xfopen(DEBUGTERM, "w"); - - { - int i; - - for (i = 1; i < argc; i++) { - debug(argv[i]); - debug("\n"); - } + for (n = 1; n < argc; n++) { + debug(argv[n]); + debug("\n"); } #endif /* Parse command-line arguments. */ - parse_args(argc, argv, &options); + parse_args(argv, &options); + + debug("calling open_tty\n"); + /* Open the tty as standard input, if it is not "-" */ + open_tty(options.tty); + + debug("duping\n"); + ndelay_off(0); + 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, &termios, "%s: TCGETS", options.tty); #ifdef SYSV_STYLE #if ENABLE_FEATURE_UTMP - /* Update the utmp file. */ + /* 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); - } + /* Make ourself a foreground process group within our session */ + tcsetpgrp(0, getpid()); + // /* 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); #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); + termios_init(&termios, options.speeds[0], &options); - /* write the modem init string and DON'T flush the buffers */ + /* 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); + full_write(1, options.initstring, strlen(options.initstring)); } - /* Optionally detect the baud rate from the modem status message. */ + /* 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); + auto_baud(line_buf, sizeof(line_buf), &termios); - /* Set the optional timer. */ + /* Set the optional timer */ if (options.timeout) alarm(options.timeout); - /* optionally wait for CR or LF before writing /etc/issue */ + /* 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) { + while (safe_read(0, &ch, 1) == 1) { ch &= 0x7f; /* strip "parity bit" */ #ifdef DEBUGGING fprintf(dbf, "read %c\n", ch); @@ -816,31 +743,42 @@ int getty_main(int argc, char **argv) } } + logname = NULL; 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), + /* 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, &termios); - while (logname == NULL) - next_speed(&termios, &options); + 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]; + ioctl(0, TCSETS, &termios); + } } /* 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); + full_write(1, "\n", 1); /* Let the login program take care of password validation. */ - - execl(options.login, options.login, "--", logname, (char *) 0); + /* We use PATH because we trust that root doesn't set "bad" PATH, + * and getty is not suid-root applet. */ + /* Hmm... with -n, logname == NULL! Is it ok? */ + BB_EXECLP(options.login, options.login, "--", logname, NULL); bb_error_msg_and_die("%s: can't exec %s", options.tty, options.login); } |