summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDenys Vlasenko <vda.linux@googlemail.com>2011-01-26 10:28:43 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2011-01-26 10:28:43 (GMT)
commit3ff9be31be0c69802b2b29f397915b9dc1689c2e (patch)
tree643ead81ca4e49e46da821c2f51b1dd1161fbf3a
parentd7c25e98bfd5dd62c19d6d672410ce61efa16801 (diff)
downloadbusybox-3ff9be31be0c69802b2b29f397915b9dc1689c2e.tar.gz
busybox-3ff9be31be0c69802b2b29f397915b9dc1689c2e.tar.bz2
getty: document bits we don't set - maybe we should set some of them?
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--loginutils/getty.c66
1 files changed, 59 insertions, 7 deletions
diff --git a/loginutils/getty.c b/loginutils/getty.c
index 4e194c4..2d2184a 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -264,10 +264,17 @@ static void termios_init(int speed)
if (option_mask32 & F_RTSCTS)
G.termios.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
#endif
+ /* Other bits in c_cflag:
+ * CSTOPB 2 stop bits (1 otherwise)
+ * PARENB Enable parity bit
+ * PARODD Use odd parity (else even)
+ * LOBLK Block job control output (??)
+ */
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__
@@ -281,18 +288,55 @@ static void termios_init(int speed)
static void termios_final(void)
{
- /* software flow control on output; and on input */
+ /* software flow control on output (stop sending if XOFF is recvd);
+ * and on input (send XOFF when buffer is full)
+ */
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/etc sigs; echo;
- * echo erase character as BS-space-BS;
- * echo NL on kill char;
- * erase entire line via BS-space-BS on kill char */
+ /* Other bits in c_iflag:
+ * IXANY Any recvd char enables output (any char is also a XON)
+ * INPCK Enable parity check
+ * IGNPAR Ignore parity errors (drop bad bytes)
+ * PARMRK Mark parity errors with 0xff, 0x00 prefix
+ * (else bad byte is received as 0x00)
+ * ISTRIP Strip parity bit
+ * IGNBRK Ignore break condition
+ * BRKINT Send SIGINT on break - maybe set this?
+ * INLCR Map NL to CR
+ * IGNCR Ignore CR
+ * ICRNL Map CR to NL
+ * IUCLC Map uppercase to lowercase
+ * IMAXBEL Echo BEL on input line too long
+ * IUTF8 [Appears to affect tty's idea of char widths,
+ * observed to improve backspacing through Unicode chars]
+ */
+
+ /* line buffered input (NL or EOL or EOF chars end a line);
+ * recognize INT/QUIT/SUSP chars;
+ * echo input chars;
+ * echo BS-SP-BS on erase character;
+ * echo kill char specially, not as ^c (ECHOKE controls how exactly);
+ * erase all input via BS-SP-BS on kill char (else go to next line)
+ */
G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
- /* echo ctrl chars as ^c; (what is ECHOPRT?) */
- /* no longer in c_lflag: | ECHOCTL | ECHOPRT */
+ /* Other bits in c_lflag:
+ * XCASE Map uppercase to \lowercase [tried, doesn't work]
+ * ECHONL Echo NL even if ECHO is not set
+ * NOFLSH Don't flush input buffer after interrupt or quit chars
+ * IEXTEN Enable extended functions (??)
+ * [glibc says it enables c_cc[LNEXT] "enter literal char"
+ * and c_cc[VDISCARD] "toggle discard buffered output" chars]
+ * ECHOCTL Echo ctrl chars as ^c (else don't echo) - maybe set this?
+ * ECHOPRT On erase, echo erased chars
+ * [qwe<BS><BS><BS> input looks like "qwe\ewq/" on screen]
+ * FLUSHO Output being flushed (c_cc[VDISCARD] is in effect)
+ * PENDIN Retype pending input at next read or input char
+ * (c_cc[VREPRINT] is being processes)
+ * TOSTOP Send SIGTTOU for background output
+ * (why "stty sane" unsets this bit?)
+ */
G.termios.c_cc[VINTR] = DEF_INTR;
G.termios.c_cc[VQUIT] = DEF_QUIT;
@@ -305,6 +349,14 @@ static void termios_final(void)
G.termios.c_cc[VSWTCH] = DEF_SWITCH;
#endif
G.termios.c_cc[VKILL] = DEF_KILL;
+ /* Other control chars:
+ * VEOL2
+ * VERASE, VWERASE - (word) erase. we may set VERASE in get_logname
+ * VREPRINT - reprint current input buffer
+ * VLNEXT, VDISCARD, VSTATUS
+ * VSUSP, VDSUSP - send (delayed) SIGTSTP
+ * VSTART, VSTOP - chars used for IXON/IXOFF
+ */
if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
bb_perror_msg_and_die("tcsetattr");