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https://github.com/sheumann/hush.git
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445 lines
11 KiB
C
445 lines
11 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* bare bones chat utility
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* inspired by ppp's chat
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*
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* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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/*
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#define ENABLE_FEATURE_CHAT_NOFAIL 1 // +126 bytes
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#define ENABLE_FEATURE_CHAT_TTY_HIFI 0 // + 70 bytes
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#define ENABLE_FEATURE_CHAT_IMPLICIT_CR 1 // + 44 bytes
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#define ENABLE_FEATURE_CHAT_SEND_ESCAPES 0 // +103 bytes
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#define ENABLE_FEATURE_CHAT_VAR_ABORT_LEN 0 // + 70 bytes
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#define ENABLE_FEATURE_CHAT_CLR_ABORT 0 // +113 bytes
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#define ENABLE_FEATURE_CHAT_SWALLOW_OPTS 0 // + 23 bytes
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*/
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// default timeout: 45 sec
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#define DEFAULT_CHAT_TIMEOUT 45*1000
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// max length of "abort string",
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// i.e. device reply which causes termination
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#define MAX_ABORT_LEN 50
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// possible exit codes
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enum {
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ERR_OK = 0, // all's well
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ERR_MEM, // read too much while expecting
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ERR_IO, // signalled or I/O error
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ERR_TIMEOUT, // timed out while expecting
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ERR_ABORT, // first abort condition was met
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// ERR_ABORT2, // second abort condition was met
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// ...
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};
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// exit code
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// N.B> 10 bytes for volatile. Why all these signals?!
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static /*volatile*/ smallint exitcode;
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// trap for critical signals
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static void signal_handler(UNUSED_PARAM int signo)
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{
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// report I/O error condition
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exitcode = ERR_IO;
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}
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#if !ENABLE_FEATURE_CHAT_IMPLICIT_CR
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#define unescape(s, nocr) unescape(s)
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#endif
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static size_t unescape(char *s, int *nocr)
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{
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char *start = s;
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char *p = s;
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while (*s) {
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char c = *s;
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// do we need special processing?
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// standard escapes + \s for space and \N for \0
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// \c inhibits terminating \r for commands and is noop for expects
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if ('\\' == c) {
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c = *++s;
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if (c) {
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#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
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if ('c' == c) {
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*nocr = 1;
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goto next;
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}
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#endif
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if ('N' == c) {
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c = '\0';
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} else if ('s' == c) {
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c = ' ';
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#if ENABLE_FEATURE_CHAT_NOFAIL
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// unescape leading dash only
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// TODO: and only for expect, not command string
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} else if ('-' == c && (start + 1 == s)) {
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//c = '-';
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#endif
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} else {
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c = bb_process_escape_sequence((const char **)&s);
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s--;
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}
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}
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// ^A becomes \001, ^B -- \002 and so on...
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} else if ('^' == c) {
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c = *++s-'@';
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}
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// put unescaped char
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*p++ = c;
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#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
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next:
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#endif
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// next char
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s++;
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}
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*p = '\0';
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return p - start;
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}
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int chat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int chat_main(int argc UNUSED_PARAM, char **argv)
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{
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// should we dump device output? to what fd? by default no.
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// this can be controlled later via ECHO {ON|OFF} chat directive
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// int echo_fd;
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bool echo = 0;
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// collection of device replies which cause unconditional termination
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llist_t *aborts = NULL;
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// inactivity period
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int timeout = DEFAULT_CHAT_TIMEOUT;
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// maximum length of abort string
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#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
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size_t max_abort_len = 0;
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#else
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#define max_abort_len MAX_ABORT_LEN
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#endif
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#if ENABLE_FEATURE_CHAT_TTY_HIFI
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struct termios tio0, tio;
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#endif
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// directive names
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enum {
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DIR_HANGUP = 0,
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DIR_ABORT,
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#if ENABLE_FEATURE_CHAT_CLR_ABORT
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DIR_CLR_ABORT,
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#endif
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DIR_TIMEOUT,
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DIR_ECHO,
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DIR_SAY,
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};
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// make x* functions fail with correct exitcode
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xfunc_error_retval = ERR_IO;
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// trap vanilla signals to prevent process from being killed suddenly
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bb_signals(0
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+ (1 << SIGHUP)
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+ (1 << SIGINT)
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+ (1 << SIGTERM)
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+ (1 << SIGPIPE)
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, signal_handler);
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#if ENABLE_FEATURE_CHAT_TTY_HIFI
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tcgetattr(STDIN_FILENO, &tio);
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tio0 = tio;
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cfmakeraw(&tio);
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tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio);
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#endif
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#if ENABLE_FEATURE_CHAT_SWALLOW_OPTS
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getopt32(argv, "vVsSE");
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argv += optind;
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#else
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argv++; // goto first arg
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#endif
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// handle chat expect-send pairs
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while (*argv) {
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// directive given? process it
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int key = index_in_strings(
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"HANGUP\0" "ABORT\0"
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#if ENABLE_FEATURE_CHAT_CLR_ABORT
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"CLR_ABORT\0"
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#endif
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"TIMEOUT\0" "ECHO\0" "SAY\0"
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, *argv
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);
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if (key >= 0) {
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// cache directive value
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char *arg = *++argv;
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// ON -> 1, anything else -> 0
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bool onoff = !strcmp("ON", arg);
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// process directive
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if (DIR_HANGUP == key) {
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// turn SIGHUP on/off
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signal(SIGHUP, onoff ? signal_handler : SIG_IGN);
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} else if (DIR_ABORT == key) {
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// append the string to abort conditions
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#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
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size_t len = strlen(arg);
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if (len > max_abort_len)
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max_abort_len = len;
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#endif
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llist_add_to_end(&aborts, arg);
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#if ENABLE_FEATURE_CHAT_CLR_ABORT
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} else if (DIR_CLR_ABORT == key) {
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// remove the string from abort conditions
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// N.B. gotta refresh maximum length too...
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#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
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max_abort_len = 0;
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#endif
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for (llist_t *l = aborts; l; l = l->link) {
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#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
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size_t len = strlen(l->data);
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#endif
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if (!strcmp(arg, l->data)) {
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llist_unlink(&aborts, l);
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continue;
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}
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#if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
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if (len > max_abort_len)
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max_abort_len = len;
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#endif
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}
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#endif
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} else if (DIR_TIMEOUT == key) {
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// set new timeout
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// -1 means OFF
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timeout = atoi(arg) * 1000;
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// 0 means default
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// >0 means value in msecs
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if (!timeout)
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timeout = DEFAULT_CHAT_TIMEOUT;
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} else if (DIR_ECHO == key) {
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// turn echo on/off
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// N.B. echo means dumping output
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// from stdin (device) to stderr
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echo = onoff;
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//TODO? echo_fd = onoff * STDERR_FILENO;
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//TODO? echo_fd = xopen(arg, O_WRONLY|O_CREAT|O_TRUNC);
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} else if (DIR_SAY == key) {
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// just print argument verbatim
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fprintf(stderr, arg);
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}
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// next, please!
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argv++;
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// ordinary expect-send pair!
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} else {
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//-----------------------
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// do expect
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//-----------------------
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int expect_len;
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size_t buf_len = 0;
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size_t max_len = max_abort_len;
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struct pollfd pfd;
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#if ENABLE_FEATURE_CHAT_NOFAIL
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int nofail = 0;
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#endif
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char *expect = *argv++;
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// sanity check: shall we really expect something?
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if (!expect)
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goto expect_done;
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#if ENABLE_FEATURE_CHAT_NOFAIL
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// if expect starts with -
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if ('-' == *expect) {
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// swallow -
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expect++;
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// and enter nofail mode
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nofail++;
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}
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#endif
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#ifdef ___TEST___BUF___ // test behaviour with a small buffer
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# undef COMMON_BUFSIZE
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# define COMMON_BUFSIZE 6
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#endif
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// expand escape sequences in expect
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expect_len = unescape(expect, &expect_len /*dummy*/);
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if (expect_len > max_len)
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max_len = expect_len;
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// sanity check:
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// we should expect more than nothing but not more than input buffer
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// TODO: later we'll get rid of fixed-size buffer
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if (!expect_len)
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goto expect_done;
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if (max_len >= COMMON_BUFSIZE) {
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exitcode = ERR_MEM;
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goto expect_done;
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}
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// get reply
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pfd.fd = STDIN_FILENO;
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pfd.events = POLLIN;
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while (!exitcode
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&& poll(&pfd, 1, timeout) > 0
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&& (pfd.revents & POLLIN)
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) {
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#define buf bb_common_bufsiz1
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llist_t *l;
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ssize_t delta;
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// read next char from device
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if (safe_read(STDIN_FILENO, buf+buf_len, 1) > 0) {
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// dump device output if ECHO ON or RECORD fname
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//TODO? if (echo_fd > 0) {
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//TODO? full_write(echo_fd, buf+buf_len, 1);
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//TODO? }
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if (echo > 0)
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full_write(STDERR_FILENO, buf+buf_len, 1);
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buf_len++;
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// move input frame if we've reached higher bound
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if (buf_len > COMMON_BUFSIZE) {
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memmove(buf, buf+buf_len-max_len, max_len);
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buf_len = max_len;
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}
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}
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// N.B. rule of thumb: values being looked for can
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// be found only at the end of input buffer
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// this allows to get rid of strstr() and memmem()
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// TODO: make expect and abort strings processed uniformly
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// abort condition is met? -> bail out
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for (l = aborts, exitcode = ERR_ABORT; l; l = l->link, ++exitcode) {
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size_t len = strlen(l->data);
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delta = buf_len-len;
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if (delta >= 0 && !memcmp(buf+delta, l->data, len))
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goto expect_done;
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}
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exitcode = ERR_OK;
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// expected reply received? -> goto next command
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delta = buf_len - expect_len;
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if (delta >= 0 && !memcmp(buf+delta, expect, expect_len))
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goto expect_done;
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#undef buf
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}
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// device timed out or unexpected reply received
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exitcode = ERR_TIMEOUT;
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expect_done:
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#if ENABLE_FEATURE_CHAT_NOFAIL
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// on success and when in nofail mode
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// we should skip following subsend-subexpect pairs
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if (nofail) {
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if (!exitcode) {
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// find last send before non-dashed expect
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while (*argv && argv[1] && '-' == argv[1][0])
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argv += 2;
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// skip the pair
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// N.B. do we really need this?!
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if (!*argv++ || !*argv++)
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break;
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}
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// nofail mode also clears all but IO errors (or signals)
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if (ERR_IO != exitcode)
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exitcode = ERR_OK;
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}
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#endif
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// bail out unless we expected successfully
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if (exitcode)
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break;
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//-----------------------
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// do send
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//-----------------------
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if (*argv) {
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#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
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int nocr = 0; // inhibit terminating command with \r
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#endif
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char *loaded = NULL; // loaded command
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size_t len;
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char *buf = *argv++;
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// if command starts with @
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// load "real" command from file named after @
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if ('@' == *buf) {
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// skip the @ and any following white-space
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trim(++buf);
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buf = loaded = xmalloc_xopen_read_close(buf, NULL);
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}
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// expand escape sequences in command
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len = unescape(buf, &nocr);
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// send command
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#if ENABLE_FEATURE_CHAT_SEND_ESCAPES
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pfd.fd = STDOUT_FILENO;
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pfd.events = POLLOUT;
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while (len && !exitcode
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&& poll(&pfd, 1, timeout) > 0
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&& (pfd.revents & POLLOUT)
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) {
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// ugly! ugly! ugly!
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// gotta send char by char to achieve this!
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// Brrr...
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// "\\d" means 1 sec delay, "\\p" means 0.01 sec delay
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// "\\K" means send BREAK
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char c = *buf;
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if ('\\' == c) {
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c = *++buf;
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if ('d' == c) {
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sleep(1);
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len--;
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continue;
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} else if ('p' == c) {
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usleep(10000);
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len--;
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continue;
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} else if ('K' == c) {
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tcsendbreak(STDOUT_FILENO, 0);
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len--;
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continue;
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} else {
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buf--;
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}
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}
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if (safe_write(STDOUT_FILENO, buf, 1) > 0) {
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len--;
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buf++;
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} else
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break;
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}
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#else
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// if (len) {
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alarm(timeout);
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len -= full_write(STDOUT_FILENO, buf, len);
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alarm(0);
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// }
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#endif
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// report I/O error if there still exists at least one non-sent char
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if (len)
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exitcode = ERR_IO;
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// free loaded command (if any)
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if (loaded)
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free(loaded);
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#if ENABLE_FEATURE_CHAT_IMPLICIT_CR
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// or terminate command with \r (if not inhibited)
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else if (!nocr)
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xwrite(STDOUT_FILENO, "\r", 1);
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#endif
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// bail out unless we sent command successfully
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if (exitcode)
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break;
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}
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}
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}
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#if ENABLE_FEATURE_CHAT_TTY_HIFI
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tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
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#endif
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return exitcode;
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}
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