getty: more simplifications; explain how we treat parity now
function old new delta getty_main 1471 1434 -37 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
6596380f52
commit
faaf8cb3fa
@ -1,15 +1,23 @@
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/* vi: set sw=4 ts=4: */
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/* Based on agetty - another getty program for Linux. By W. Z. Venema 1989
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/*
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* Based on agetty - another getty program for Linux. By W. Z. Venema 1989
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* Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
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* This program is freely distributable.
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*
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* option added by Eric Rasmussen <ear@usfirst.org> - 12/28/95
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*
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* 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org>
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* - added Native Language Support
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* - Added Native Language Support
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*
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* 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net>
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* - enable hardware flow control before displaying /etc/issue
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* - Enabled hardware flow control before displaying /etc/issue
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*
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* 2011-01 Venys Vlasenko
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* - Removed parity detection code. It can't work reliably:
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* if all chars received have bit 7 cleared and odd (or even) parity,
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* it is impossible to determine whether other side is 8-bit,no-parity
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* or 7-bit,odd(even)-parity. It also interferes with non-ASCII usernames.
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* - From now on, we assume that parity is correctly set.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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@ -23,13 +31,7 @@
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# define IUCLC 0
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#endif
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/*
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* Some heuristics to find out what environment we are in: if it is not
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* System V, assume it is SunOS 4.
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*/
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#ifdef LOGIN_PROCESS /* defined in System V utmp.h */
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# include <sys/utsname.h>
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#else /* if !sysV style, wtmp/utmp code is off */
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#ifndef LOGIN_PROCESS
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# undef ENABLE_FEATURE_UTMP
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# undef ENABLE_FEATURE_WTMP
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# define ENABLE_FEATURE_UTMP 0
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@ -37,7 +39,7 @@
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#endif
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/* The following is used for understandable diagnostics. */
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/* The following is used for understandable diagnostics */
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#ifdef DEBUGGING
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static FILE *dbf;
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# define DEBUGTERM "/dev/ttyp0"
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@ -64,14 +66,14 @@ static FILE *dbf;
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*/
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#define ISSUE "/etc/issue"
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/* Some shorthands for control characters. */
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/* Some shorthands for control characters */
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#define CTL(x) ((x) ^ 0100) /* Assumes ASCII dialect */
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#define CR CTL('M') /* carriage return */
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#define NL CTL('J') /* line feed */
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#define BS CTL('H') /* back space */
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#define DEL CTL('?') /* delete */
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/* Defaults for line-editing etc. characters; you may want to change this. */
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/* Defaults for line-editing etc. characters; you may want to change this */
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#define DEF_ERASE DEL /* default erase character */
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#define DEF_INTR CTL('C') /* default interrupt character */
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#define DEF_QUIT CTL('\\') /* default quit char */
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@ -81,23 +83,22 @@ static FILE *dbf;
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#define DEF_SWITCH 0 /* default switch char */
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/*
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* When multiple baud rates are specified on the command line, the first one
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* we will try is the first one specified.
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* When multiple baud rates are specified on the command line,
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* the first one we will try is the first one specified.
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*/
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#define MAX_SPEED 10 /* max. nr. of baud rates */
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struct globals {
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unsigned timeout; /* time-out period */
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const char *login; /* login program */
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const char *fakehost;
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const char *tty; /* name of tty */
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const char *initstring; /* modem init string */
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const char *issue; /* alternative issue file */
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int numspeed; /* number of baud rates to try */
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int speeds[MAX_SPEED]; /* baud rates to be tried */
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unsigned char eol; /* end-of-line char seen (CR or NL) */
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struct termios termios; /* terminal mode bits */
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/* Storage for things detected while the login name was read. */
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unsigned char erase; /* erase character */
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unsigned char eol; /* end-of-line character */
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char line_buf[128];
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};
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@ -168,14 +169,14 @@ static void parse_speeds(char *arg)
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}
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/* parse command-line arguments */
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static void parse_args(char **argv, char **fakehost_p)
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static void parse_args(char **argv)
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{
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char *ts;
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int flags;
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opt_complementary = "-2:t+"; /* at least 2 args; -t N */
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flags = getopt32(argv, opt_string,
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&G.initstring, fakehost_p, &G.issue,
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&G.initstring, &G.fakehost, &G.issue,
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&G.login, &G.timeout
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);
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if (flags & F_INITSTRING) {
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@ -206,17 +207,17 @@ static void parse_args(char **argv, char **fakehost_p)
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/* set up tty as standard input, output, error */
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static void open_tty(void)
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{
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/* Set up new standard input, unless we are given an already opened port. */
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/* Set up new standard input, unless we are given an already opened port */
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if (NOT_LONE_DASH(G.tty)) {
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if (G.tty[0] != '/')
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G.tty = xasprintf("/dev/%s", G.tty); /* will leak it */
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/* Open the tty as standard input. */
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/* Open the tty as standard input */
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debug("open(2)\n");
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close(0);
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xopen(G.tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */
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/* Set proper protections and ownership. */
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/* Set proper protections and ownership */
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fchown(0, 0, 0); /* 0:0 */
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fchmod(0, 0620); /* crw--w---- */
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} else {
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@ -229,7 +230,13 @@ static void open_tty(void)
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}
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}
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/* initialize termios settings */
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/* We manipulate termios this way:
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* - first, we read existing termios settings
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* - termios_init modifies some parts and sets it
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* - auto_baud and/or BREAK processing can set different speed and set termios
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* - termios_final again modifies some parts and sets termios before
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* execing login
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*/
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static void termios_init(int speed)
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{
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/* Flush input and output queues, important for modems!
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@ -240,7 +247,7 @@ static void termios_init(int speed)
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usleep(100*1000); /* 0.1 sec */
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tcflush(STDIN_FILENO, TCIOFLUSH);
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/* Set speed if it wasn't specified as "0" on command line. */
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/* Set speed if it wasn't specified as "0" on command line */
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if (speed != B0)
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cfsetspeed(&G.termios, speed);
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@ -271,13 +278,44 @@ static void termios_init(int speed)
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debug("term_io 2\n");
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}
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static void termios_final(void)
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{
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/* General terminal-independent stuff */
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G.termios.c_iflag |= IXON | IXOFF; /* 2-way flow control */
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G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
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/* no longer in lflag: | ECHOCTL | ECHOPRT */
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G.termios.c_oflag |= OPOST;
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/* G.termios.c_cflag = 0; */
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G.termios.c_cc[VINTR] = DEF_INTR;
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G.termios.c_cc[VQUIT] = DEF_QUIT;
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G.termios.c_cc[VEOF] = DEF_EOF;
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G.termios.c_cc[VEOL] = DEF_EOL;
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#ifdef VSWTC
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G.termios.c_cc[VSWTC] = DEF_SWITCH;
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#endif
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/* Account for special characters seen in input */
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if (G.eol == CR) {
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G.termios.c_iflag |= ICRNL; /* map CR in input to NL */
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/* already done by termios_init */
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/* G.termios.c_oflag |= ONLCR; map NL in output to CR-NL */
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}
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G.termios.c_cc[VKILL] = DEF_KILL;
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#ifdef CRTSCTS
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/* Optionally enable hardware flow control */
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if (option_mask32 & F_RTSCTS)
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G.termios.c_cflag |= CRTSCTS;
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#endif
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/* Finally, make the new settings effective */
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if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
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bb_perror_msg_and_die("tcsetattr");
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}
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/* extract baud rate from modem status message */
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static void auto_baud(void)
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{
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int speed;
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int vmin;
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unsigned iflag;
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char *bp;
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int nread;
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/*
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@ -296,12 +334,9 @@ static void auto_baud(void)
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*/
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/*
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* Use 7-bit characters, don't block if input queue is empty. Errors will
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* be dealt with later on.
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* Don't block if input queue is empty.
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* Errors will be dealt with later on.
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*/
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iflag = G.termios.c_iflag;
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G.termios.c_iflag |= ISTRIP; /* enable 8th-bit stripping */
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vmin = G.termios.c_cc[VMIN];
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G.termios.c_cc[VMIN] = 0; /* don't block if queue empty */
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tcsetattr_stdin_TCSANOW(&G.termios);
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@ -312,6 +347,8 @@ static void auto_baud(void)
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sleep(1);
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nread = safe_read(STDIN_FILENO, G.line_buf, sizeof(G.line_buf) - 1);
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if (nread > 0) {
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int speed;
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char *bp;
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G.line_buf[nread] = '\0';
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for (bp = G.line_buf; bp < G.line_buf + nread; bp++) {
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if (isdigit(*bp)) {
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@ -323,38 +360,38 @@ static void auto_baud(void)
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}
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}
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/* Restore terminal settings. Errors will be dealt with later on. */
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G.termios.c_iflag = iflag;
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G.termios.c_cc[VMIN] = vmin;
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/* Restore terminal settings. Errors will be dealt with later on */
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G.termios.c_cc[VMIN] = 1; /* restore to value set by termios_init */
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tcsetattr_stdin_TCSANOW(&G.termios);
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}
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/* get user name, establish parity, speed, erase, kill, eol;
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* return NULL on BREAK, logname on success */
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* return NULL on BREAK, logname on success
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*/
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static char *get_logname(void)
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{
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char *bp;
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char c;
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/* Flush pending input (esp. after parsing or switching the baud rate). */
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/* Flush pending input (esp. after parsing or switching the baud rate) */
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usleep(100*1000); /* 0.1 sec */
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tcflush(STDIN_FILENO, TCIOFLUSH);
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/* Prompt for and read a login name. */
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/* Prompt for and read a login name */
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G.line_buf[0] = '\0';
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while (!G.line_buf[0]) {
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/* Write issue file and prompt. */
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/* Write issue file and prompt */
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#ifdef ISSUE
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if (!(option_mask32 & F_NOISSUE))
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print_login_issue(G.issue, G.tty);
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#endif
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print_login_prompt();
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/* Read name, watch for break, parity, erase, kill, end-of-line. */
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/* Read name, watch for break, parity, erase, kill, end-of-line */
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bp = G.line_buf;
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G.eol = '\0';
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while (1) {
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/* Do not report trivial EINTR/EIO errors. */
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/* Do not report trivial EINTR/EIO errors */
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errno = EINTR; /* make read of 0 bytes be silent too */
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if (read(STDIN_FILENO, &c, 1) < 1) {
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if (errno == EINTR || errno == EIO)
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@ -367,7 +404,7 @@ static char *get_logname(void)
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if (c == '\0' && G.numspeed > 1)
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return NULL;
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/* Do erase, kill and end-of-line processing. */
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/* Do erase, kill and end-of-line processing */
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switch (c) {
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case CR:
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case NL:
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@ -376,7 +413,7 @@ static char *get_logname(void)
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goto got_logname;
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case BS:
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case DEL:
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G.erase = c;
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G.termios.c_cc[VERASE] = c;
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if (bp > G.line_buf) {
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full_write(STDOUT_FILENO, "\010 \010", 3);
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bp--;
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@ -407,61 +444,22 @@ static char *get_logname(void)
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return G.line_buf;
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}
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/* set the final tty mode bits */
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static void termios_final(void)
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{
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/* General terminal-independent stuff. */
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G.termios.c_iflag |= IXON | IXOFF; /* 2-way flow control */
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G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
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/* no longer in lflag: | ECHOCTL | ECHOPRT */
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G.termios.c_oflag |= OPOST;
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/* G.termios.c_cflag = 0; */
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G.termios.c_cc[VINTR] = DEF_INTR; /* default interrupt */
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G.termios.c_cc[VQUIT] = DEF_QUIT; /* default quit */
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G.termios.c_cc[VEOF] = DEF_EOF; /* default EOF character */
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G.termios.c_cc[VEOL] = DEF_EOL;
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#ifdef VSWTC
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G.termios.c_cc[VSWTC] = DEF_SWITCH; /* default switch character */
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#endif
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/* Account for special characters seen in input. */
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if (G.eol == CR) {
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G.termios.c_iflag |= ICRNL; /* map CR in input to NL */
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G.termios.c_oflag |= ONLCR; /* map NL in output to CR-NL */
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}
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G.termios.c_cc[VERASE] = G.erase; /* set erase character */
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G.termios.c_cc[VKILL] = DEF_KILL; /* set kill character */
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#ifdef CRTSCTS
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/* Optionally enable hardware flow control */
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if (option_mask32 & F_RTSCTS)
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G.termios.c_cflag |= CRTSCTS;
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#endif
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/* Finally, make the new settings effective */
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if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
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bb_perror_msg_and_die("tcsetattr");
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}
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int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int getty_main(int argc UNUSED_PARAM, char **argv)
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{
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int n;
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pid_t pid;
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char *fakehost = NULL; /* Fake hostname for ut_host */
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char *logname;
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INIT_G();
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G.login = _PATH_LOGIN; /* default login program */
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G.initstring = ""; /* modem init string */
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#ifdef ISSUE
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G.issue = ISSUE; /* default issue file */
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#endif
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G.erase = DEF_ERASE;
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G.eol = CR;
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/* Parse command-line arguments. */
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parse_args(argv, &fakehost);
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/* Parse command-line arguments */
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parse_args(argv);
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logmode = LOGMODE_NONE;
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@ -524,9 +522,9 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
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#endif
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/* Update the utmp file. This tty is ours now! */
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update_utmp(pid, LOGIN_PROCESS, G.tty, "LOGIN", fakehost);
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update_utmp(pid, LOGIN_PROCESS, G.tty, "LOGIN", G.fakehost);
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/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
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/* Initialize the termios settings (raw mode, eight-bit, blocking i/o) */
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debug("calling termios_init\n");
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termios_init(G.speeds[0]);
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@ -563,30 +561,30 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
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int baud_index = 0;
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while (1) {
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/* Read the login name. */
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/* Read the login name */
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debug("reading login name\n");
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logname = get_logname();
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if (logname)
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break;
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/* We are here only if G.numspeed > 1. */
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/* We are here only if G.numspeed > 1 */
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baud_index = (baud_index + 1) % G.numspeed;
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cfsetspeed(&G.termios, G.speeds[baud_index]);
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tcsetattr_stdin_TCSANOW(&G.termios);
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}
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}
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/* Disable timer. */
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/* Disable timer */
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alarm(0);
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/* Finalize the termios settings. */
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/* Finalize the termios settings */
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termios_final();
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/* Now the newline character should be properly written. */
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/* Now the newline character should be properly written */
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full_write(STDOUT_FILENO, "\n", 1);
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/* Let the login program take care of password validation. */
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/* Let the login program take care of password validation */
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/* We use PATH because we trust that root doesn't set "bad" PATH,
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* and getty is not suid-root applet. */
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* and getty is not suid-root applet */
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/* With -n, logname == NULL, and login will ask for username instead */
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BB_EXECLP(G.login, G.login, "--", logname, NULL);
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bb_error_msg_and_die("can't execute '%s'", G.login);
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