getty: explain every bit in termios; remove redundant stuff in termios_final
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
ea023eacad
commit
d8494934a7
@ -53,6 +53,7 @@ int resize_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
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*/
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fprintf(stderr, ESC"7" ESC"[r" ESC"[999;999H" ESC"[6n");
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alarm(3); /* Just in case terminal won't answer */
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//BUG: death by signal won't restore termios
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scanf(ESC"[%hu;%huR", &w.ws_row, &w.ws_col);
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fprintf(stderr, ESC"8");
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@ -106,15 +106,15 @@ struct globals {
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//usage:#define getty_full_usage "\n\n"
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//usage: "Open a tty, prompt for a login name, then invoke /bin/login\n"
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//usage: "\nOptions:"
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//usage: "\n -h Enable hardware (RTS/CTS) flow control"
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//usage: "\n -i Don't display /etc/issue"
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//usage: "\n -L Local line, set CLOCAL on it"
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//usage: "\n -h Enable hardware RTS/CTS flow control"
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//usage: "\n -L Set CLOCAL (ignore Carrier Detect state)"
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//usage: "\n -m Get baud rate from modem's CONNECT status message"
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//usage: "\n -n Don't prompt for login name"
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//usage: "\n -w Wait for CR or LF before sending /etc/issue"
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//usage: "\n -n Don't prompt for a login name"
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//usage: "\n -i Don't display /etc/issue"
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//usage: "\n -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue"
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//usage: "\n -l LOGIN Invoke LOGIN instead of /bin/login"
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//usage: "\n -t SEC Terminate after SEC if no username is read"
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//usage: "\n -t SEC Terminate after SEC if no login name is read"
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//usage: "\n -I INITSTR Send INITSTR before anything else"
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//usage: "\n -H HOST Log HOST into the utmp file as the hostname"
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//usage: "\n"
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@ -251,20 +251,27 @@ static void termios_init(int speed)
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* reads will be done in raw mode anyway. Errors will be dealt with
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* later on.
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*/
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/* 8 bits; hangup (drop DTR) on last close; enable receive */
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G.termios.c_cflag = CS8 | HUPCL | CREAD;
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if (option_mask32 & F_LOCAL)
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if (option_mask32 & F_LOCAL) {
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/* ignore Carrier Detect pin:
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* opens don't block when CD is low,
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* losing CD doesn't hang up processes whose ctty is this tty
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*/
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G.termios.c_cflag |= CLOCAL;
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G.termios.c_iflag = 0;
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G.termios.c_lflag = 0;
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G.termios.c_oflag = OPOST | ONLCR;
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G.termios.c_cc[VMIN] = 1;
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G.termios.c_cc[VTIME] = 0;
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#ifdef __linux__
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G.termios.c_line = 0;
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#endif
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}
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#ifdef CRTSCTS
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if (option_mask32 & F_RTSCTS)
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G.termios.c_cflag |= CRTSCTS;
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G.termios.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
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#endif
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G.termios.c_iflag = 0;
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G.termios.c_lflag = 0;
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/* non-raw output; add CR to each NL */
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G.termios.c_oflag = OPOST | ONLCR;
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G.termios.c_cc[VMIN] = 1; /* block reads if < 1 char is available */
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G.termios.c_cc[VTIME] = 0; /* no timeout (reads block forever) */
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#ifdef __linux__
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G.termios.c_line = 0;
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#endif
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tcsetattr_stdin_TCSANOW(&G.termios);
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@ -274,12 +281,17 @@ static void termios_init(int speed)
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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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/* software flow control on output; and on input */
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G.termios.c_iflag |= IXON | IXOFF;
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if (G.eol == '\r') {
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G.termios.c_iflag |= ICRNL; /* map CR on input to NL */
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}
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/* non-raw input; enable SIGINT/QUIT/ec sigs; echo; echo NL on kill char;
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* erase entire line via BS-space-BS on kill char */
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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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/* echo ctrl chars as ^c; (what is ECHOPRT?) */
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/* no longer in c_lflag: | ECHOCTL | ECHOPRT */
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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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@ -290,22 +302,8 @@ static void termios_final(void)
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#ifdef VSWTCH
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G.termios.c_cc[VSWTCH] = 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 == '\r') {
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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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@ -330,11 +328,7 @@ static void auto_baud(void)
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* modem status messages is enabled.
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*/
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/*
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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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G.termios.c_cc[VMIN] = 0; /* don't block if queue empty */
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G.termios.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
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tcsetattr_stdin_TCSANOW(&G.termios);
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/*
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@ -538,6 +532,7 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
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/* Set the optional timer */
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alarm(G.timeout); /* if 0, alarm is not set */
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//BUG: death by signal won't restore termios
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/* Optionally wait for CR or LF before writing /etc/issue */
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if (option_mask32 & F_WAITCRLF) {
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