On Monday 04 February 2008 19:28, [EMAIL PROTECTED] wrote:
> Attached is microcom updated.
// without this we never get POLLIN on sfd
// until piped stdin is drained
if (-1 != timeout)
safe_poll(pfd, 1, timeout);
This is very surprising.
I don't have any serial devices here to test, so I picked
a "device" which always has some data to read from it:
# strace -o mc.log ./busybox microcom -X <TODO /dev/zero
I made microcom ignore setattr error:
static int xset1(int fd, struct termios *tio, const char *device)
{
...
return 0; //ret;
}
and disabled suspicious code:
//// if (-1 != timeout)
//// safe_poll(pfd, 1, timeout);
strace log clearly shows that poll returns BOTH descriptors
with POLLIN set in revents:
execve("./busybox", ["./busybox", "microcom", "-X", "/dev/zero"], [/* 32 vars
*/]) = 0
...
ioctl(3, SNDCTL_TMR_CONTINUE or TCSETSF, {B9600 -opost -isig -icanon -echo
...}) = -1 ENOTTY (Inappropriate ioctl for device)
write(2, "microcom: can\'t tcsetattr for /d"..., 72) = 72
poll([{fd=3, events=POLLIN, revents=POLLIN}, {fd=0, events=POLLIN,
revents=POLLIN}], 2, 100) = 2
^^^^^^^^^^^^^^
^^^^^^^^^^^^^^
read(3, "\0", 1) = 1
write(1, "\0", 1) = 1
read(0, "B", 1) = 1
write(3, "B", 1) = 1
poll([{fd=3, events=POLLIN, revents=POLLIN}, {fd=0, events=POLLIN,
revents=POLLIN}], 2, 100) = 2
read(3, "\0", 1) = 1
write(1, "\0", 1) = 1
read(0, "u", 1) = 1
write(3, "u", 1)
...
Can you show me the strace of similar microcom command with real serial device?
My microcom.c is attached.
BTW: please take a look at telnetd.c - it has full-fledged piping loop,
with non-blocking fds, buffered io (minicom does it char-by-char),
etc... For one, it wouldn't hang if one write() would block (minicom will),
because it checks that fd is ready to accept some output data.
Maybe generalize and reuse that one?
(I'm applying your patch with small changes)
--
vda
/* vi: set sw=4 ts=4: */
/*
* bare bones 'talk to modem' program - similar to 'cu -l $device'
* inspired by mgetty's microcom
*
* Copyright (C) 2007 by Vladimir Dronnikov <[EMAIL PROTECTED]>
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
/* All known arches use small ints for signals */
static volatile smallint signalled;
static void signal_handler(int signo)
{
signalled = signo;
}
// set raw tty mode
static void xget1(int fd, struct termios *t, struct termios *oldt)
{
tcgetattr(fd, oldt);
*t = *oldt;
cfmakeraw(t);
// t->c_lflag &= ~(ISIG|ICANON|ECHO|IEXTEN);
// t->c_iflag &= ~(BRKINT|IXON|ICRNL);
// t->c_oflag &= ~(ONLCR);
// t->c_cc[VMIN] = 1;
// t->c_cc[VTIME] = 0;
}
static int xset1(int fd, struct termios *tio, const char *device)
{
int ret = tcsetattr(fd, TCSAFLUSH, tio);
if (ret) {
bb_perror_msg("can't tcsetattr for %s", device);
}
return 0; //ret;
}
int microcom_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int microcom_main(int argc, char **argv)
{
int sfd;
int nfd;
struct pollfd pfd[2];
struct termios tio0, tiosfd, tio;
char *device_lock_file;
enum {
OPT_X = 1 << 0, // do not respect Ctrl-X, Ctrl-@
OPT_s = 1 << 1, // baudrate
OPT_t = 1 << 2 // wait for device response, msecs
};
speed_t speed = 9600;
int timeout = 100; // 0.1 sec timeout
// fetch options
char *opt_s;
char *opt_t;
unsigned opts;
opt_complementary = "=1"; /* exactly one arg should be there */
opts = getopt32(argv, "Xs:t:", &opt_s, &opt_t);
// apply options
if (opts & OPT_s)
speed = xatou(opt_s);
if (opts & OPT_t)
timeout = xatou(opt_t);
// argc -= optind;
argv += optind;
// try to create lock file in /var/lock
device_lock_file = (char *)bb_basename(argv[0]);
device_lock_file = xasprintf("/var/lock/LCK..%s", device_lock_file);
sfd = open(device_lock_file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
if (sfd < 0) {
if (errno == EEXIST)
bb_perror_msg_and_die("can't lock");
if (ENABLE_FEATURE_CLEAN_UP)
free(device_lock_file);
device_lock_file = NULL;
}
if (sfd > 0) {
// %4d to make mgetty happy. It treats 4-bytes lock files as binary,
// not text, PID. Making 5+ char file. Brrr...
char *s = xasprintf("%4d\n", getpid());
write(sfd, s, strlen(s));
if (ENABLE_FEATURE_CLEAN_UP)
free(s);
close(sfd);
}
// setup signals
sig_catch(SIGHUP, signal_handler);
sig_catch(SIGINT, signal_handler);
sig_catch(SIGTERM, signal_handler);
sig_catch(SIGPIPE, signal_handler);
// error exit code if we fail to open the device
signalled = 1;
// open device
sfd = open_or_warn(argv[0], O_RDWR | O_NOCTTY | O_NONBLOCK);
if (sfd < 0)
goto done;
fcntl(sfd, F_SETFL, O_RDWR | O_NOCTTY);
/* put stdin to "raw mode" (if stdin is a TTY),
handle one character at a time */
if (isatty(STDIN_FILENO)) {
xget1(STDIN_FILENO, &tio, &tio0);
if (xset1(STDIN_FILENO, &tio, "stdin"))
goto done;
timeout = -1; // tty input? -> set infinite timeout for poll()
}
// same thing for modem
xget1(sfd, &tio, &tiosfd);
// order device to hang up at exit
tio.c_cflag |= (CREAD|HUPCL);
// if (!istty)
// tio.c_iflag |= (IGNCR);
// set device speed
cfsetspeed(&tio, tty_value_to_baud(speed));
if (xset1(sfd, &tio, argv[0]))
goto restore0_and_done;
// main loop: check with poll(), then read/write bytes across
pfd[0].fd = sfd;
pfd[0].events = POLLIN;
pfd[1].fd = STDIN_FILENO;
pfd[1].events = POLLIN;
signalled = 0;
nfd = 2;
while (!signalled && safe_poll(pfd, nfd, timeout) > 0) {
char c;
if (pfd[0].revents & POLLIN) {
// read from device -> write to stdout
if (safe_read(sfd, &c, 1) > 0)
write(STDOUT_FILENO, &c, 1);
}
if (pfd[1].revents & POLLIN) {
// read from stdin -> write to device
if (safe_read(STDIN_FILENO, &c, 1) < 1) {
// skip poll()ing stdin if we got EOF/error
pfd[1].revents = 0;
nfd--;
continue;
}
// do we need special processing?
if (!(opts & OPT_X)) {
// ^@ sends Break
if (VINTR == c) {
tcsendbreak(sfd, 0);
continue;
}
// ^X exits
if (24 == c)
break;
}
write(sfd, &c, 1);
// without this we never get POLLIN on sfd
// until piped stdin is drained
//// if (-1 != timeout)
//// safe_poll(pfd, 1, timeout);
}
}
tcsetattr(sfd, TCSAFLUSH, &tiosfd);
restore0_and_done:
// timeout == -1 -- stdin is a tty
if (-1 == timeout)
tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
done:
if (device_lock_file)
unlink(device_lock_file);
return signalled;
}
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