| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Based on agetty - another getty program for Linux. By W. Z. Venema 1989
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| 4 | * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
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| 5 | * This program is freely distributable.
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| 6 | *
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| 7 | * option added by Eric Rasmussen <ear@usfirst.org> - 12/28/95
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| 8 | *
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| 9 | * 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org>
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| 10 | * - Added Native Language Support
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| 11 | *
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| 12 | * 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net>
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| 13 | * - Enabled hardware flow control before displaying /etc/issue
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| 14 | *
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| 15 | * 2011-01 Venys Vlasenko
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| 16 | * - Removed parity detection code. It can't work reliably:
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| 17 | * if all chars received have bit 7 cleared and odd (or even) parity,
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| 18 | * it is impossible to determine whether other side is 8-bit,no-parity
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| 19 | * or 7-bit,odd(even)-parity. It also interferes with non-ASCII usernames.
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| 20 | * - From now on, we assume that parity is correctly set.
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| 21 | *
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| 22 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 23 | */
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| 24 | //config:config GETTY
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| 25 | //config: bool "getty"
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| 26 | //config: default y
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| 27 | //config: select FEATURE_SYSLOG
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| 28 | //config: help
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| 29 | //config: getty lets you log in on a tty. It is normally invoked by init.
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| 30 | //config:
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| 31 | //config: Note that you can save a few bytes by disabling it and
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| 32 | //config: using login applet directly.
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| 33 | //config: If you need to reset tty attributes before calling login,
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| 34 | //config: this script approximates getty:
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| 35 | //config:
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| 36 | //config: exec </dev/$1 >/dev/$1 2>&1 || exit 1
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| 37 | //config: reset
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| 38 | //config: stty sane; stty ispeed 38400; stty ospeed 38400
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| 39 | //config: printf "%s login: " "`hostname`"
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| 40 | //config: read -r login
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| 41 | //config: exec /bin/login "$login"
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| 42 |
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| 43 | //applet:IF_GETTY(APPLET(getty, BB_DIR_SBIN, BB_SUID_DROP))
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| 44 |
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| 45 | //kbuild:lib-$(CONFIG_GETTY) += getty.o
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| 46 |
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| 47 | #include "libbb.h"
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| 48 | #include <syslog.h>
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| 49 | #ifndef IUCLC
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| 50 | # define IUCLC 0
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| 51 | #endif
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| 52 |
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| 53 | #ifndef LOGIN_PROCESS
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| 54 | # undef ENABLE_FEATURE_UTMP
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| 55 | # undef ENABLE_FEATURE_WTMP
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| 56 | # define ENABLE_FEATURE_UTMP 0
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| 57 | # define ENABLE_FEATURE_WTMP 0
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| 58 | #endif
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| 59 |
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| 60 |
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| 61 | /* The following is used for understandable diagnostics */
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| 62 | #ifdef DEBUGGING
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| 63 | static FILE *dbf;
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| 64 | # define DEBUGTERM "/dev/ttyp0"
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| 65 | # define debug(...) do { fprintf(dbf, __VA_ARGS__); fflush(dbf); } while (0)
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| 66 | #else
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| 67 | # define debug(...) ((void)0)
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| 68 | #endif
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| 69 |
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| 70 |
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| 71 | /*
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| 72 | * Things you may want to modify.
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| 73 | *
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| 74 | * You may disagree with the default line-editing etc. characters defined
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| 75 | * below. Note, however, that DEL cannot be used for interrupt generation
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| 76 | * and for line editing at the same time.
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| 77 | */
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| 78 | #undef _PATH_LOGIN
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| 79 | #define _PATH_LOGIN "/bin/login"
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| 80 |
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| 81 | /* Displayed before the login prompt.
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| 82 | * If ISSUE is not defined, getty will never display the contents of the
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| 83 | * /etc/issue file. You will not want to spit out large "issue" files at the
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| 84 | * wrong baud rate.
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| 85 | */
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| 86 | #define ISSUE "/etc/issue"
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| 87 |
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| 88 | /* Macro to build Ctrl-LETTER. Assumes ASCII dialect */
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| 89 | #define CTL(x) ((x) ^ 0100)
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| 90 |
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| 91 | /*
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| 92 | * When multiple baud rates are specified on the command line,
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| 93 | * the first one we will try is the first one specified.
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| 94 | */
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| 95 | #define MAX_SPEED 10 /* max. nr. of baud rates */
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| 96 |
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| 97 | struct globals {
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| 98 | unsigned timeout;
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| 99 | const char *login; /* login program */
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| 100 | const char *fakehost;
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| 101 | const char *tty_name;
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| 102 | char *initstring; /* modem init string */
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| 103 | const char *issue; /* alternative issue file */
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| 104 | int numspeed; /* number of baud rates to try */
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| 105 | int speeds[MAX_SPEED]; /* baud rates to be tried */
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| 106 | unsigned char eol; /* end-of-line char seen (CR or NL) */
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| 107 | struct termios tty_attrs;
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| 108 | char line_buf[128];
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| 109 | };
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| 110 |
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| 111 | #define G (*ptr_to_globals)
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| 112 | #define INIT_G() do { \
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| 113 | SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
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| 114 | } while (0)
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| 115 |
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| 116 | //usage:#define getty_trivial_usage
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| 117 | //usage: "[OPTIONS] BAUD_RATE[,BAUD_RATE]... TTY [TERMTYPE]"
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| 118 | //usage:#define getty_full_usage "\n\n"
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| 119 | //usage: "Open TTY, prompt for login name, then invoke /bin/login\n"
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| 120 | //usage: "\n -h Enable hardware RTS/CTS flow control"
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| 121 | //usage: "\n -L Set CLOCAL (ignore Carrier Detect state)"
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| 122 | //usage: "\n -m Get baud rate from modem's CONNECT status message"
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| 123 | //usage: "\n -n Don't prompt for login name"
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| 124 | //usage: "\n -w Wait for CR or LF before sending /etc/issue"
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| 125 | //usage: "\n -i Don't display /etc/issue"
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| 126 | //usage: "\n -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue"
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| 127 | //usage: "\n -l LOGIN Invoke LOGIN instead of /bin/login"
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| 128 | //usage: "\n -t SEC Terminate after SEC if no login name is read"
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| 129 | //usage: "\n -I INITSTR Send INITSTR before anything else"
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| 130 | //usage: "\n -H HOST Log HOST into the utmp file as the hostname"
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| 131 | //usage: "\n"
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| 132 | //usage: "\nBAUD_RATE of 0 leaves it unchanged"
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| 133 |
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| 134 | static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:wn";
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| 135 | #define F_INITSTRING (1 << 0) /* -I */
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| 136 | #define F_LOCAL (1 << 1) /* -L */
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| 137 | #define F_FAKEHOST (1 << 2) /* -H */
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| 138 | #define F_CUSTISSUE (1 << 3) /* -f */
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| 139 | #define F_RTSCTS (1 << 4) /* -h */
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| 140 | #define F_NOISSUE (1 << 5) /* -i */
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| 141 | #define F_LOGIN (1 << 6) /* -l */
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| 142 | #define F_PARSE (1 << 7) /* -m */
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| 143 | #define F_TIMEOUT (1 << 8) /* -t */
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| 144 | #define F_WAITCRLF (1 << 9) /* -w */
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| 145 | #define F_NOPROMPT (1 << 10) /* -n */
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| 146 |
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| 147 |
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| 148 | /* convert speed string to speed code; return <= 0 on failure */
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| 149 | static int bcode(const char *s)
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| 150 | {
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| 151 | int value = bb_strtou(s, NULL, 10); /* yes, int is intended! */
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| 152 | if (value < 0) /* bad terminating char, overflow, etc */
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| 153 | return value;
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| 154 | return tty_value_to_baud(value);
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| 155 | }
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| 156 |
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| 157 | /* parse alternate baud rates */
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| 158 | static void parse_speeds(char *arg)
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| 159 | {
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| 160 | char *cp;
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| 161 |
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| 162 | /* NB: at least one iteration is always done */
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| 163 | debug("entered parse_speeds\n");
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| 164 | while ((cp = strsep(&arg, ",")) != NULL) {
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| 165 | G.speeds[G.numspeed] = bcode(cp);
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| 166 | if (G.speeds[G.numspeed] < 0)
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| 167 | bb_error_msg_and_die("bad speed: %s", cp);
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| 168 | /* note: arg "0" turns into speed B0 */
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| 169 | G.numspeed++;
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| 170 | if (G.numspeed > MAX_SPEED)
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| 171 | bb_error_msg_and_die("too many alternate speeds");
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| 172 | }
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| 173 | debug("exiting parse_speeds\n");
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| 174 | }
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| 175 |
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| 176 | /* parse command-line arguments */
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| 177 | static void parse_args(char **argv)
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| 178 | {
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| 179 | char *ts;
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| 180 | int flags;
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| 181 |
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| 182 | opt_complementary = "-2:t+"; /* at least 2 args; -t N */
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| 183 | flags = getopt32(argv, opt_string,
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| 184 | &G.initstring, &G.fakehost, &G.issue,
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| 185 | &G.login, &G.timeout
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| 186 | );
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| 187 | if (flags & F_INITSTRING) {
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| 188 | G.initstring = xstrdup(G.initstring);
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| 189 | /* decode \ddd octal codes into chars */
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| 190 | strcpy_and_process_escape_sequences(G.initstring, G.initstring);
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| 191 | }
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| 192 | argv += optind;
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| 193 | debug("after getopt\n");
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| 194 |
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| 195 | /* We loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
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| 196 | G.tty_name = argv[0];
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| 197 | ts = argv[1]; /* baud rate(s) */
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| 198 | if (isdigit(argv[0][0])) {
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| 199 | /* A number first, assume it's a speed (BSD style) */
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| 200 | G.tty_name = ts; /* tty name is in argv[1] */
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| 201 | ts = argv[0]; /* baud rate(s) */
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| 202 | }
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| 203 | parse_speeds(ts);
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| 204 |
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| 205 | if (argv[2])
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| 206 | xsetenv("TERM", argv[2]);
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| 207 |
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| 208 | debug("exiting parse_args\n");
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| 209 | }
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| 210 |
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| 211 | /* set up tty as standard input, output, error */
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| 212 | static void open_tty(void)
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| 213 | {
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| 214 | /* Set up new standard input, unless we are given an already opened port */
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| 215 | if (NOT_LONE_DASH(G.tty_name)) {
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| 216 | if (G.tty_name[0] != '/')
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| 217 | G.tty_name = xasprintf("/dev/%s", G.tty_name); /* will leak it */
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| 218 |
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| 219 | /* Open the tty as standard input */
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| 220 | debug("open(2)\n");
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| 221 | close(0);
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| 222 | xopen(G.tty_name, O_RDWR | O_NONBLOCK); /* uses fd 0 */
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| 223 |
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| 224 | /* Set proper protections and ownership */
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| 225 | fchown(0, 0, 0); /* 0:0 */
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| 226 | fchmod(0, 0620); /* crw--w---- */
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| 227 | } else {
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| 228 | char *n;
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| 229 | /*
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| 230 | * Standard input should already be connected to an open port.
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| 231 | * Make sure it is open for read/write.
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| 232 | */
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| 233 | if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
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| 234 | bb_error_msg_and_die("stdin is not open for read/write");
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| 235 |
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| 236 | /* Try to get real tty name instead of "-" */
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| 237 | n = xmalloc_ttyname(0);
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| 238 | if (n)
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| 239 | G.tty_name = n;
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| 240 | }
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| 241 | applet_name = xasprintf("getty: %s", skip_dev_pfx(G.tty_name));
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| 242 | }
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| 243 |
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| 244 | static void set_tty_attrs(void)
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| 245 | {
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| 246 | if (tcsetattr_stdin_TCSANOW(&G.tty_attrs) < 0)
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| 247 | bb_perror_msg_and_die("tcsetattr");
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| 248 | }
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| 249 |
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| 250 | /* We manipulate tty_attrs this way:
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| 251 | * - first, we read existing tty_attrs
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| 252 | * - init_tty_attrs modifies some parts and sets it
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| 253 | * - auto_baud and/or BREAK processing can set different speed and set tty attrs
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| 254 | * - finalize_tty_attrs again modifies some parts and sets tty attrs before
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| 255 | * execing login
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| 256 | */
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| 257 | static void init_tty_attrs(int speed)
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| 258 | {
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| 259 | /* Try to drain output buffer, with 5 sec timeout.
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| 260 | * Added on request from users of ~600 baud serial interface
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| 261 | * with biggish buffer on a 90MHz CPU.
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| 262 | * They were losing hundreds of bytes of buffered output
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| 263 | * on tcflush.
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| 264 | */
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| 265 | signal_no_SA_RESTART_empty_mask(SIGALRM, record_signo);
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| 266 | alarm(5);
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| 267 | tcdrain(STDIN_FILENO);
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| 268 | alarm(0);
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| 269 |
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| 270 | /* Flush input and output queues, important for modems! */
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| 271 | tcflush(STDIN_FILENO, TCIOFLUSH);
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| 272 |
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| 273 | /* Set speed if it wasn't specified as "0" on command line */
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| 274 | if (speed != B0)
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| 275 | cfsetspeed(&G.tty_attrs, speed);
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| 276 |
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| 277 | /* Initial settings: 8-bit characters, raw mode, blocking i/o.
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| 278 | * Special characters are set after we have read the login name; all
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| 279 | * reads will be done in raw mode anyway.
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| 280 | */
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| 281 | /* Clear all bits except: */
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| 282 | G.tty_attrs.c_cflag &= (0
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| 283 | /* 2 stop bits (1 otherwise)
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| 284 | * Enable parity bit (both on input and output)
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| 285 | * Odd parity (else even)
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| 286 | */
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| 287 | | CSTOPB | PARENB | PARODD
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| 288 | #ifdef CMSPAR
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| 289 | | CMSPAR /* mark or space parity */
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| 290 | #endif
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| 291 | #ifdef CBAUD
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| 292 | | CBAUD /* (output) baud rate */
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| 293 | #endif
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| 294 | #ifdef CBAUDEX
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| 295 | | CBAUDEX /* (output) baud rate */
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| 296 | #endif
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| 297 | #ifdef CIBAUD
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| 298 | | CIBAUD /* input baud rate */
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| 299 | #endif
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| 300 | );
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| 301 | /* Set: 8 bits; hang up (drop DTR) on last close; enable receive */
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| 302 | G.tty_attrs.c_cflag |= CS8 | HUPCL | CREAD;
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| 303 | if (option_mask32 & F_LOCAL) {
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| 304 | /* ignore Carrier Detect pin:
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| 305 | * opens don't block when CD is low,
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| 306 | * losing CD doesn't hang up processes whose ctty is this tty
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| 307 | */
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| 308 | G.tty_attrs.c_cflag |= CLOCAL;
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| 309 | }
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| 310 | #ifdef CRTSCTS
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| 311 | if (option_mask32 & F_RTSCTS)
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| 312 | G.tty_attrs.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
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| 313 | #endif
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| 314 | G.tty_attrs.c_iflag = 0;
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| 315 | G.tty_attrs.c_lflag = 0;
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| 316 | /* non-raw output; add CR to each NL */
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| 317 | G.tty_attrs.c_oflag = OPOST | ONLCR;
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| 318 |
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| 319 | /* reads would block only if < 1 char is available */
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| 320 | G.tty_attrs.c_cc[VMIN] = 1;
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| 321 | /* no timeout (reads block forever) */
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| 322 | G.tty_attrs.c_cc[VTIME] = 0;
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| 323 | #ifdef __linux__
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| 324 | G.tty_attrs.c_line = 0;
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| 325 | #endif
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| 326 |
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| 327 | set_tty_attrs();
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| 328 |
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| 329 | debug("term_io 2\n");
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| 330 | }
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| 331 |
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| 332 | static void finalize_tty_attrs(void)
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| 333 | {
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| 334 | /* software flow control on output (stop sending if XOFF is recvd);
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| 335 | * and on input (send XOFF when buffer is full)
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| 336 | */
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| 337 | G.tty_attrs.c_iflag |= IXON | IXOFF;
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| 338 | if (G.eol == '\r') {
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| 339 | G.tty_attrs.c_iflag |= ICRNL; /* map CR on input to NL */
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| 340 | }
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| 341 | /* Other bits in c_iflag:
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| 342 | * IXANY Any recvd char enables output (any char is also a XON)
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| 343 | * INPCK Enable parity check
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| 344 | * IGNPAR Ignore parity errors (drop bad bytes)
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| 345 | * PARMRK Mark parity errors with 0xff, 0x00 prefix
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| 346 | * (else bad byte is received as 0x00)
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| 347 | * ISTRIP Strip parity bit
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| 348 | * IGNBRK Ignore break condition
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| 349 | * BRKINT Send SIGINT on break - maybe set this?
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| 350 | * INLCR Map NL to CR
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| 351 | * IGNCR Ignore CR
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| 352 | * ICRNL Map CR to NL
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| 353 | * IUCLC Map uppercase to lowercase
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| 354 | * IMAXBEL Echo BEL on input line too long
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| 355 | * IUTF8 Appears to affect tty's idea of char widths,
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| 356 | * observed to improve backspacing through Unicode chars
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| 357 | */
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| 358 |
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| 359 | /* ICANON line buffered input (NL or EOL or EOF chars end a line);
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| 360 | * ISIG recognize INT/QUIT/SUSP chars;
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| 361 | * ECHO echo input chars;
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| 362 | * ECHOE echo BS-SP-BS on erase character;
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| 363 | * ECHOK echo kill char specially, not as ^c (ECHOKE controls how exactly);
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| 364 | * ECHOKE erase all input via BS-SP-BS on kill char (else go to next line)
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| 365 | * ECHOCTL Echo ctrl chars as ^c (else echo verbatim:
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| 366 | * e.g. up arrow emits "ESC-something" and thus moves cursor up!)
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| 367 | */
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| 368 | G.tty_attrs.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE | ECHOCTL;
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| 369 | /* Other bits in c_lflag:
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| 370 | * XCASE Map uppercase to \lowercase [tried, doesn't work]
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| 371 | * ECHONL Echo NL even if ECHO is not set
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| 372 | * ECHOPRT On erase, echo erased chars
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| 373 | * [qwe<BS><BS><BS> input looks like "qwe\ewq/" on screen]
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| 374 | * NOFLSH Don't flush input buffer after interrupt or quit chars
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| 375 | * IEXTEN Enable extended functions (??)
|
|---|
| 376 | * [glibc says it enables c_cc[LNEXT] "enter literal char"
|
|---|
| 377 | * and c_cc[VDISCARD] "toggle discard buffered output" chars]
|
|---|
| 378 | * FLUSHO Output being flushed (c_cc[VDISCARD] is in effect)
|
|---|
| 379 | * PENDIN Retype pending input at next read or input char
|
|---|
| 380 | * (c_cc[VREPRINT] is being processed)
|
|---|
| 381 | * TOSTOP Send SIGTTOU for background output
|
|---|
| 382 | * (why "stty sane" unsets this bit?)
|
|---|
| 383 | */
|
|---|
| 384 |
|
|---|
| 385 | G.tty_attrs.c_cc[VINTR] = CTL('C');
|
|---|
| 386 | G.tty_attrs.c_cc[VQUIT] = CTL('\\');
|
|---|
| 387 | G.tty_attrs.c_cc[VEOF] = CTL('D');
|
|---|
| 388 | G.tty_attrs.c_cc[VEOL] = '\n';
|
|---|
| 389 | #ifdef VSWTC
|
|---|
| 390 | G.tty_attrs.c_cc[VSWTC] = 0;
|
|---|
| 391 | #endif
|
|---|
| 392 | #ifdef VSWTCH
|
|---|
| 393 | G.tty_attrs.c_cc[VSWTCH] = 0;
|
|---|
| 394 | #endif
|
|---|
| 395 | G.tty_attrs.c_cc[VKILL] = CTL('U');
|
|---|
| 396 | /* Other control chars:
|
|---|
| 397 | * VEOL2
|
|---|
| 398 | * VERASE, VWERASE - (word) erase. we may set VERASE in get_logname
|
|---|
| 399 | * VREPRINT - reprint current input buffer
|
|---|
| 400 | * VLNEXT, VDISCARD, VSTATUS
|
|---|
| 401 | * VSUSP, VDSUSP - send (delayed) SIGTSTP
|
|---|
| 402 | * VSTART, VSTOP - chars used for IXON/IXOFF
|
|---|
| 403 | */
|
|---|
| 404 |
|
|---|
| 405 | set_tty_attrs();
|
|---|
| 406 |
|
|---|
| 407 | /* Now the newline character should be properly written */
|
|---|
| 408 | full_write(STDOUT_FILENO, "\n", 1);
|
|---|
| 409 | }
|
|---|
| 410 |
|
|---|
| 411 | /* extract baud rate from modem status message */
|
|---|
| 412 | static void auto_baud(void)
|
|---|
| 413 | {
|
|---|
| 414 | int nread;
|
|---|
| 415 |
|
|---|
| 416 | /*
|
|---|
| 417 | * This works only if the modem produces its status code AFTER raising
|
|---|
| 418 | * the DCD line, and if the computer is fast enough to set the proper
|
|---|
| 419 | * baud rate before the message has gone by. We expect a message of the
|
|---|
| 420 | * following format:
|
|---|
| 421 | *
|
|---|
| 422 | * <junk><number><junk>
|
|---|
| 423 | *
|
|---|
| 424 | * The number is interpreted as the baud rate of the incoming call. If the
|
|---|
| 425 | * modem does not tell us the baud rate within one second, we will keep
|
|---|
| 426 | * using the current baud rate. It is advisable to enable BREAK
|
|---|
| 427 | * processing (comma-separated list of baud rates) if the processing of
|
|---|
| 428 | * modem status messages is enabled.
|
|---|
| 429 | */
|
|---|
| 430 |
|
|---|
| 431 | G.tty_attrs.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
|
|---|
| 432 | set_tty_attrs();
|
|---|
| 433 |
|
|---|
| 434 | /*
|
|---|
| 435 | * Wait for a while, then read everything the modem has said so far and
|
|---|
| 436 | * try to extract the speed of the dial-in call.
|
|---|
| 437 | */
|
|---|
| 438 | sleep(1);
|
|---|
| 439 | nread = safe_read(STDIN_FILENO, G.line_buf, sizeof(G.line_buf) - 1);
|
|---|
| 440 | if (nread > 0) {
|
|---|
| 441 | int speed;
|
|---|
| 442 | char *bp;
|
|---|
| 443 | G.line_buf[nread] = '\0';
|
|---|
| 444 | for (bp = G.line_buf; bp < G.line_buf + nread; bp++) {
|
|---|
| 445 | if (isdigit(*bp)) {
|
|---|
| 446 | speed = bcode(bp);
|
|---|
| 447 | if (speed > 0)
|
|---|
| 448 | cfsetspeed(&G.tty_attrs, speed);
|
|---|
| 449 | break;
|
|---|
| 450 | }
|
|---|
| 451 | }
|
|---|
| 452 | }
|
|---|
| 453 |
|
|---|
| 454 | /* Restore terminal settings */
|
|---|
| 455 | G.tty_attrs.c_cc[VMIN] = 1; /* restore to value set by init_tty_attrs */
|
|---|
| 456 | set_tty_attrs();
|
|---|
| 457 | }
|
|---|
| 458 |
|
|---|
| 459 | /* get user name, establish parity, speed, erase, kill, eol;
|
|---|
| 460 | * return NULL on BREAK, logname on success
|
|---|
| 461 | */
|
|---|
| 462 | static char *get_logname(void)
|
|---|
| 463 | {
|
|---|
| 464 | char *bp;
|
|---|
| 465 | char c;
|
|---|
| 466 |
|
|---|
| 467 | /* Flush pending input (esp. after parsing or switching the baud rate) */
|
|---|
| 468 | usleep(100*1000); /* 0.1 sec */
|
|---|
| 469 | tcflush(STDIN_FILENO, TCIFLUSH);
|
|---|
| 470 |
|
|---|
| 471 | /* Prompt for and read a login name */
|
|---|
| 472 | do {
|
|---|
| 473 | /* Write issue file and prompt */
|
|---|
| 474 | #ifdef ISSUE
|
|---|
| 475 | if (!(option_mask32 & F_NOISSUE))
|
|---|
| 476 | print_login_issue(G.issue, G.tty_name);
|
|---|
| 477 | #endif
|
|---|
| 478 | print_login_prompt();
|
|---|
| 479 |
|
|---|
| 480 | /* Read name, watch for break, erase, kill, end-of-line */
|
|---|
| 481 | bp = G.line_buf;
|
|---|
| 482 | while (1) {
|
|---|
| 483 | /* Do not report trivial EINTR/EIO errors */
|
|---|
| 484 | errno = EINTR; /* make read of 0 bytes be silent too */
|
|---|
| 485 | if (read(STDIN_FILENO, &c, 1) < 1) {
|
|---|
| 486 | finalize_tty_attrs();
|
|---|
| 487 | if (errno == EINTR || errno == EIO)
|
|---|
| 488 | exit(EXIT_SUCCESS);
|
|---|
| 489 | bb_perror_msg_and_die(bb_msg_read_error);
|
|---|
| 490 | }
|
|---|
| 491 |
|
|---|
| 492 | switch (c) {
|
|---|
| 493 | case '\r':
|
|---|
| 494 | case '\n':
|
|---|
| 495 | *bp = '\0';
|
|---|
| 496 | G.eol = c;
|
|---|
| 497 | goto got_logname;
|
|---|
| 498 | case CTL('H'):
|
|---|
| 499 | case 0x7f:
|
|---|
| 500 | G.tty_attrs.c_cc[VERASE] = c;
|
|---|
| 501 | if (bp > G.line_buf) {
|
|---|
| 502 | full_write(STDOUT_FILENO, "\010 \010", 3);
|
|---|
| 503 | bp--;
|
|---|
| 504 | }
|
|---|
| 505 | break;
|
|---|
| 506 | case CTL('U'):
|
|---|
| 507 | while (bp > G.line_buf) {
|
|---|
| 508 | full_write(STDOUT_FILENO, "\010 \010", 3);
|
|---|
| 509 | bp--;
|
|---|
| 510 | }
|
|---|
| 511 | break;
|
|---|
| 512 | case CTL('C'):
|
|---|
| 513 | case CTL('D'):
|
|---|
| 514 | finalize_tty_attrs();
|
|---|
| 515 | exit(EXIT_SUCCESS);
|
|---|
| 516 | case '\0':
|
|---|
| 517 | /* BREAK. If we have speeds to try,
|
|---|
| 518 | * return NULL (will switch speeds and return here) */
|
|---|
| 519 | if (G.numspeed > 1)
|
|---|
| 520 | return NULL;
|
|---|
| 521 | /* fall through and ignore it */
|
|---|
| 522 | default:
|
|---|
| 523 | if ((unsigned char)c < ' ') {
|
|---|
| 524 | /* ignore garbage characters */
|
|---|
| 525 | } else if ((int)(bp - G.line_buf) < sizeof(G.line_buf) - 1) {
|
|---|
| 526 | /* echo and store the character */
|
|---|
| 527 | full_write(STDOUT_FILENO, &c, 1);
|
|---|
| 528 | *bp++ = c;
|
|---|
| 529 | }
|
|---|
| 530 | break;
|
|---|
| 531 | }
|
|---|
| 532 | } /* end of get char loop */
|
|---|
| 533 | got_logname: ;
|
|---|
| 534 | } while (G.line_buf[0] == '\0'); /* while logname is empty */
|
|---|
| 535 |
|
|---|
| 536 | return G.line_buf;
|
|---|
| 537 | }
|
|---|
| 538 |
|
|---|
| 539 | static void alarm_handler(int sig UNUSED_PARAM)
|
|---|
| 540 | {
|
|---|
| 541 | finalize_tty_attrs();
|
|---|
| 542 | _exit(EXIT_SUCCESS);
|
|---|
| 543 | }
|
|---|
| 544 |
|
|---|
| 545 | static void sleep10(void)
|
|---|
| 546 | {
|
|---|
| 547 | sleep(10);
|
|---|
| 548 | }
|
|---|
| 549 |
|
|---|
| 550 | int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|---|
| 551 | int getty_main(int argc UNUSED_PARAM, char **argv)
|
|---|
| 552 | {
|
|---|
| 553 | int n;
|
|---|
| 554 | pid_t pid, tsid;
|
|---|
| 555 | char *logname;
|
|---|
| 556 |
|
|---|
| 557 | INIT_G();
|
|---|
| 558 | G.login = _PATH_LOGIN; /* default login program */
|
|---|
| 559 | #ifdef ISSUE
|
|---|
| 560 | G.issue = ISSUE; /* default issue file */
|
|---|
| 561 | #endif
|
|---|
| 562 | G.eol = '\r';
|
|---|
| 563 |
|
|---|
| 564 | /* Parse command-line arguments */
|
|---|
| 565 | parse_args(argv);
|
|---|
| 566 |
|
|---|
| 567 | /* Create new session and pgrp, lose controlling tty */
|
|---|
| 568 | pid = setsid(); /* this also gives us our pid :) */
|
|---|
| 569 | if (pid < 0) {
|
|---|
| 570 | int fd;
|
|---|
| 571 | /* :(
|
|---|
| 572 | * docs/ctty.htm says:
|
|---|
| 573 | * "This is allowed only when the current process
|
|---|
| 574 | * is not a process group leader".
|
|---|
| 575 | * Thus, setsid() will fail if we _already_ are
|
|---|
| 576 | * a session leader - which is quite possible for getty!
|
|---|
| 577 | */
|
|---|
| 578 | pid = getpid();
|
|---|
| 579 | if (getsid(0) != pid) {
|
|---|
| 580 | //for debugging:
|
|---|
| 581 | //bb_perror_msg_and_die("setsid failed:"
|
|---|
| 582 | // " pid %d ppid %d"
|
|---|
| 583 | // " sid %d pgid %d",
|
|---|
| 584 | // pid, getppid(),
|
|---|
| 585 | // getsid(0), getpgid(0));
|
|---|
| 586 | bb_perror_msg_and_die("setsid");
|
|---|
| 587 | /*
|
|---|
| 588 | * When we can end up here?
|
|---|
| 589 | * Example: setsid() fails when run alone in interactive shell:
|
|---|
| 590 | * # getty 115200 /dev/tty2
|
|---|
| 591 | * because shell's child (getty) is put in a new process group.
|
|---|
| 592 | * But doesn't fail if shell is not interactive
|
|---|
| 593 | * (and therefore doesn't create process groups for pipes),
|
|---|
| 594 | * or if getty is not the first process in the process group:
|
|---|
| 595 | * # true | getty 115200 /dev/tty2
|
|---|
| 596 | */
|
|---|
| 597 | }
|
|---|
| 598 | /* Looks like we are already a session leader.
|
|---|
| 599 | * In this case (setsid failed) we may still have ctty,
|
|---|
| 600 | * and it may be different from tty we need to control!
|
|---|
| 601 | * If we still have ctty, on Linux ioctl(TIOCSCTTY)
|
|---|
| 602 | * (which we are going to use a bit later) always fails -
|
|---|
| 603 | * even if we try to take ctty which is already ours!
|
|---|
| 604 | * Try to drop old ctty now to prevent that.
|
|---|
| 605 | * Use O_NONBLOCK: old ctty may be a serial line.
|
|---|
| 606 | */
|
|---|
| 607 | fd = open("/dev/tty", O_RDWR | O_NONBLOCK);
|
|---|
| 608 | if (fd >= 0) {
|
|---|
| 609 | /* TIOCNOTTY sends SIGHUP to the foreground
|
|---|
| 610 | * process group - which may include us!
|
|---|
| 611 | * Make sure to not die on it:
|
|---|
| 612 | */
|
|---|
| 613 | sighandler_t old = signal(SIGHUP, SIG_IGN);
|
|---|
| 614 | ioctl(fd, TIOCNOTTY);
|
|---|
| 615 | close(fd);
|
|---|
| 616 | signal(SIGHUP, old);
|
|---|
| 617 | }
|
|---|
| 618 | }
|
|---|
| 619 |
|
|---|
| 620 | /* Close stdio, and stray descriptors, just in case */
|
|---|
| 621 | n = xopen(bb_dev_null, O_RDWR);
|
|---|
| 622 | /* dup2(n, 0); - no, we need to handle "getty - 9600" too */
|
|---|
| 623 | xdup2(n, 1);
|
|---|
| 624 | xdup2(n, 2);
|
|---|
| 625 | while (n > 2)
|
|---|
| 626 | close(n--);
|
|---|
| 627 |
|
|---|
| 628 | /* Logging. We want special flavor of error_msg_and_die */
|
|---|
| 629 | die_func = sleep10;
|
|---|
| 630 | msg_eol = "\r\n";
|
|---|
| 631 | /* most likely will internally use fd #3 in CLOEXEC mode: */
|
|---|
| 632 | openlog(applet_name, LOG_PID, LOG_AUTH);
|
|---|
| 633 | logmode = LOGMODE_BOTH;
|
|---|
| 634 |
|
|---|
| 635 | #ifdef DEBUGGING
|
|---|
| 636 | dbf = xfopen_for_write(DEBUGTERM);
|
|---|
| 637 | for (n = 1; argv[n]; n++) {
|
|---|
| 638 | debug(argv[n]);
|
|---|
| 639 | debug("\n");
|
|---|
| 640 | }
|
|---|
| 641 | #endif
|
|---|
| 642 |
|
|---|
| 643 | /* Open the tty as standard input, if it is not "-" */
|
|---|
| 644 | debug("calling open_tty\n");
|
|---|
| 645 | open_tty();
|
|---|
| 646 | ndelay_off(STDIN_FILENO);
|
|---|
| 647 | debug("duping\n");
|
|---|
| 648 | xdup2(STDIN_FILENO, 1);
|
|---|
| 649 | xdup2(STDIN_FILENO, 2);
|
|---|
| 650 |
|
|---|
| 651 | /* Steal ctty if we don't have it yet */
|
|---|
| 652 | tsid = tcgetsid(STDIN_FILENO);
|
|---|
| 653 | if (tsid < 0 || pid != tsid) {
|
|---|
| 654 | if (ioctl(STDIN_FILENO, TIOCSCTTY, /*force:*/ (long)1) < 0)
|
|---|
| 655 | bb_perror_msg_and_die("TIOCSCTTY");
|
|---|
| 656 | }
|
|---|
| 657 |
|
|---|
| 658 | #ifdef __linux__
|
|---|
| 659 | /* Make ourself a foreground process group within our session */
|
|---|
| 660 | if (tcsetpgrp(STDIN_FILENO, pid) < 0)
|
|---|
| 661 | bb_perror_msg_and_die("tcsetpgrp");
|
|---|
| 662 | #endif
|
|---|
| 663 |
|
|---|
| 664 | /*
|
|---|
| 665 | * The following ioctl will fail if stdin is not a tty, but also when
|
|---|
| 666 | * there is noise on the modem control lines. In the latter case, the
|
|---|
| 667 | * common course of action is (1) fix your cables (2) give the modem more
|
|---|
| 668 | * time to properly reset after hanging up. SunOS users can achieve (2)
|
|---|
| 669 | * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
|
|---|
| 670 | * 5 seconds seems to be a good value.
|
|---|
| 671 | */
|
|---|
| 672 | if (tcgetattr(STDIN_FILENO, &G.tty_attrs) < 0)
|
|---|
| 673 | bb_perror_msg_and_die("tcgetattr");
|
|---|
| 674 |
|
|---|
| 675 | /* Update the utmp file. This tty is ours now! */
|
|---|
| 676 | update_utmp(pid, LOGIN_PROCESS, G.tty_name, "LOGIN", G.fakehost);
|
|---|
| 677 |
|
|---|
| 678 | /* Initialize tty attrs (raw mode, eight-bit, blocking i/o) */
|
|---|
| 679 | debug("calling init_tty_attrs\n");
|
|---|
| 680 | init_tty_attrs(G.speeds[0]);
|
|---|
| 681 |
|
|---|
| 682 | /* Write the modem init string and DON'T flush the buffers */
|
|---|
| 683 | if (option_mask32 & F_INITSTRING) {
|
|---|
| 684 | debug("writing init string\n");
|
|---|
| 685 | full_write1_str(G.initstring);
|
|---|
| 686 | }
|
|---|
| 687 |
|
|---|
| 688 | /* Optionally detect the baud rate from the modem status message */
|
|---|
| 689 | debug("before autobaud\n");
|
|---|
| 690 | if (option_mask32 & F_PARSE)
|
|---|
| 691 | auto_baud();
|
|---|
| 692 |
|
|---|
| 693 | /* Set the optional timer */
|
|---|
| 694 | signal(SIGALRM, alarm_handler);
|
|---|
| 695 | alarm(G.timeout); /* if 0, alarm is not set */
|
|---|
| 696 |
|
|---|
| 697 | /* Optionally wait for CR or LF before writing /etc/issue */
|
|---|
| 698 | if (option_mask32 & F_WAITCRLF) {
|
|---|
| 699 | char ch;
|
|---|
| 700 | debug("waiting for cr-lf\n");
|
|---|
| 701 | while (safe_read(STDIN_FILENO, &ch, 1) == 1) {
|
|---|
| 702 | debug("read %x\n", (unsigned char)ch);
|
|---|
| 703 | if (ch == '\n' || ch == '\r')
|
|---|
| 704 | break;
|
|---|
| 705 | }
|
|---|
| 706 | }
|
|---|
| 707 |
|
|---|
| 708 | logname = NULL;
|
|---|
| 709 | if (!(option_mask32 & F_NOPROMPT)) {
|
|---|
| 710 | /* NB: init_tty_attrs already set line speed
|
|---|
| 711 | * to G.speeds[0] */
|
|---|
| 712 | int baud_index = 0;
|
|---|
| 713 |
|
|---|
| 714 | while (1) {
|
|---|
| 715 | /* Read the login name */
|
|---|
| 716 | debug("reading login name\n");
|
|---|
| 717 | logname = get_logname();
|
|---|
| 718 | if (logname)
|
|---|
| 719 | break;
|
|---|
| 720 | /* We are here only if G.numspeed > 1 */
|
|---|
| 721 | baud_index = (baud_index + 1) % G.numspeed;
|
|---|
| 722 | cfsetspeed(&G.tty_attrs, G.speeds[baud_index]);
|
|---|
| 723 | set_tty_attrs();
|
|---|
| 724 | }
|
|---|
| 725 | }
|
|---|
| 726 |
|
|---|
| 727 | /* Disable timer */
|
|---|
| 728 | alarm(0);
|
|---|
| 729 |
|
|---|
| 730 | finalize_tty_attrs();
|
|---|
| 731 |
|
|---|
| 732 | /* Let the login program take care of password validation */
|
|---|
| 733 | /* We use PATH because we trust that root doesn't set "bad" PATH,
|
|---|
| 734 | * and getty is not suid-root applet */
|
|---|
| 735 | /* With -n, logname == NULL, and login will ask for username instead */
|
|---|
| 736 | BB_EXECLP(G.login, G.login, "--", logname, (char *)0);
|
|---|
| 737 | bb_error_msg_and_die("can't execute '%s'", G.login);
|
|---|
| 738 | }
|
|---|
