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 2011-01-26 03:26:38 +01:00
parent ea023eacad
commit d8494934a7
2 changed files with 35 additions and 39 deletions

View File

@ -53,6 +53,7 @@ int resize_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
*/ */
fprintf(stderr, ESC"7" ESC"[r" ESC"[999;999H" ESC"[6n"); fprintf(stderr, ESC"7" ESC"[r" ESC"[999;999H" ESC"[6n");
alarm(3); /* Just in case terminal won't answer */ alarm(3); /* Just in case terminal won't answer */
//BUG: death by signal won't restore termios
scanf(ESC"[%hu;%huR", &w.ws_row, &w.ws_col); scanf(ESC"[%hu;%huR", &w.ws_row, &w.ws_col);
fprintf(stderr, ESC"8"); fprintf(stderr, ESC"8");

View File

@ -106,15 +106,15 @@ struct globals {
//usage:#define getty_full_usage "\n\n" //usage:#define getty_full_usage "\n\n"
//usage: "Open a tty, prompt for a login name, then invoke /bin/login\n" //usage: "Open a tty, prompt for a login name, then invoke /bin/login\n"
//usage: "\nOptions:" //usage: "\nOptions:"
//usage: "\n -h Enable hardware (RTS/CTS) flow control" //usage: "\n -h Enable hardware RTS/CTS flow control"
//usage: "\n -i Don't display /etc/issue" //usage: "\n -L Set CLOCAL (ignore Carrier Detect state)"
//usage: "\n -L Local line, set CLOCAL on it"
//usage: "\n -m Get baud rate from modem's CONNECT status message" //usage: "\n -m Get baud rate from modem's CONNECT status message"
//usage: "\n -n Don't prompt for login name"
//usage: "\n -w Wait for CR or LF before sending /etc/issue" //usage: "\n -w Wait for CR or LF before sending /etc/issue"
//usage: "\n -n Don't prompt for a login name" //usage: "\n -i Don't display /etc/issue"
//usage: "\n -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue" //usage: "\n -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue"
//usage: "\n -l LOGIN Invoke LOGIN instead of /bin/login" //usage: "\n -l LOGIN Invoke LOGIN instead of /bin/login"
//usage: "\n -t SEC Terminate after SEC if no username is read" //usage: "\n -t SEC Terminate after SEC if no login name is read"
//usage: "\n -I INITSTR Send INITSTR before anything else" //usage: "\n -I INITSTR Send INITSTR before anything else"
//usage: "\n -H HOST Log HOST into the utmp file as the hostname" //usage: "\n -H HOST Log HOST into the utmp file as the hostname"
//usage: "\n" //usage: "\n"
@ -251,20 +251,27 @@ static void termios_init(int speed)
* reads will be done in raw mode anyway. Errors will be dealt with * reads will be done in raw mode anyway. Errors will be dealt with
* later on. * later on.
*/ */
/* 8 bits; hangup (drop DTR) on last close; enable receive */
G.termios.c_cflag = CS8 | HUPCL | CREAD; G.termios.c_cflag = CS8 | HUPCL | CREAD;
if (option_mask32 & F_LOCAL) if (option_mask32 & F_LOCAL) {
/* ignore Carrier Detect pin:
* opens don't block when CD is low,
* losing CD doesn't hang up processes whose ctty is this tty
*/
G.termios.c_cflag |= CLOCAL; G.termios.c_cflag |= CLOCAL;
G.termios.c_iflag = 0; }
G.termios.c_lflag = 0;
G.termios.c_oflag = OPOST | ONLCR;
G.termios.c_cc[VMIN] = 1;
G.termios.c_cc[VTIME] = 0;
#ifdef __linux__
G.termios.c_line = 0;
#endif
#ifdef CRTSCTS #ifdef CRTSCTS
if (option_mask32 & F_RTSCTS) if (option_mask32 & F_RTSCTS)
G.termios.c_cflag |= CRTSCTS; G.termios.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
#endif
G.termios.c_iflag = 0;
G.termios.c_lflag = 0;
/* non-raw output; add CR to each NL */
G.termios.c_oflag = OPOST | ONLCR;
G.termios.c_cc[VMIN] = 1; /* block reads if < 1 char is available */
G.termios.c_cc[VTIME] = 0; /* no timeout (reads block forever) */
#ifdef __linux__
G.termios.c_line = 0;
#endif #endif
tcsetattr_stdin_TCSANOW(&G.termios); tcsetattr_stdin_TCSANOW(&G.termios);
@ -274,12 +281,17 @@ static void termios_init(int speed)
static void termios_final(void) static void termios_final(void)
{ {
/* General terminal-independent stuff */ /* software flow control on output; and on input */
G.termios.c_iflag |= IXON | IXOFF; /* 2-way flow control */ G.termios.c_iflag |= IXON | IXOFF;
if (G.eol == '\r') {
G.termios.c_iflag |= ICRNL; /* map CR on input to NL */
}
/* non-raw input; enable SIGINT/QUIT/ec sigs; echo; echo NL on kill char;
* erase entire line via BS-space-BS on kill char */
G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE; G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
/* no longer in lflag: | ECHOCTL | ECHOPRT */ /* echo ctrl chars as ^c; (what is ECHOPRT?) */
G.termios.c_oflag |= OPOST; /* no longer in c_lflag: | ECHOCTL | ECHOPRT */
/* G.termios.c_cflag = 0; */
G.termios.c_cc[VINTR] = DEF_INTR; G.termios.c_cc[VINTR] = DEF_INTR;
G.termios.c_cc[VQUIT] = DEF_QUIT; G.termios.c_cc[VQUIT] = DEF_QUIT;
G.termios.c_cc[VEOF] = DEF_EOF; G.termios.c_cc[VEOF] = DEF_EOF;
@ -290,22 +302,8 @@ static void termios_final(void)
#ifdef VSWTCH #ifdef VSWTCH
G.termios.c_cc[VSWTCH] = DEF_SWITCH; G.termios.c_cc[VSWTCH] = DEF_SWITCH;
#endif #endif
/* Account for special characters seen in input */
if (G.eol == '\r') {
G.termios.c_iflag |= ICRNL; /* map CR in input to NL */
/* already done by termios_init */
/* G.termios.c_oflag |= ONLCR; map NL in output to CR-NL */
}
G.termios.c_cc[VKILL] = DEF_KILL; G.termios.c_cc[VKILL] = DEF_KILL;
#ifdef CRTSCTS
/* Optionally enable hardware flow control */
if (option_mask32 & F_RTSCTS)
G.termios.c_cflag |= CRTSCTS;
#endif
/* Finally, make the new settings effective */
if (tcsetattr_stdin_TCSANOW(&G.termios) < 0) if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
bb_perror_msg_and_die("tcsetattr"); bb_perror_msg_and_die("tcsetattr");
} }
@ -330,11 +328,7 @@ static void auto_baud(void)
* modem status messages is enabled. * modem status messages is enabled.
*/ */
/* G.termios.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
* Don't block if input queue is empty.
* Errors will be dealt with later on.
*/
G.termios.c_cc[VMIN] = 0; /* don't block if queue empty */
tcsetattr_stdin_TCSANOW(&G.termios); tcsetattr_stdin_TCSANOW(&G.termios);
/* /*
@ -538,6 +532,7 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
/* Set the optional timer */ /* Set the optional timer */
alarm(G.timeout); /* if 0, alarm is not set */ alarm(G.timeout); /* if 0, alarm is not set */
//BUG: death by signal won't restore termios
/* Optionally wait for CR or LF before writing /etc/issue */ /* Optionally wait for CR or LF before writing /etc/issue */
if (option_mask32 & F_WAITCRLF) { if (option_mask32 & F_WAITCRLF) {