/* vi: set sw=4 ts=4: */ /* * bare bones chat utility * inspired by ppp's chat * * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com> * * Licensed under GPLv2, see file LICENSE in this source tree. */ //usage:#define chat_trivial_usage //usage: "EXPECT [SEND [EXPECT [SEND...]]]" //usage:#define chat_full_usage "\n\n" //usage: "Useful for interacting with a modem connected to stdin/stdout.\n" //usage: "A script consists of one or more \"expect-send\" pairs of strings,\n" //usage: "each pair is a pair of arguments. Example:\n" //usage: "chat '' ATZ OK ATD123456 CONNECT '' ogin: pppuser word: ppppass '~'" #include "libbb.h" // default timeout: 45 sec #define DEFAULT_CHAT_TIMEOUT 45*1000 // max length of "abort string", // i.e. device reply which causes termination #define MAX_ABORT_LEN 50 // possible exit codes enum { ERR_OK = 0, // all's well ERR_MEM, // read too much while expecting ERR_IO, // signalled or I/O error ERR_TIMEOUT, // timed out while expecting ERR_ABORT, // first abort condition was met // ERR_ABORT2, // second abort condition was met // ... }; // exit code #define exitcode bb_got_signal // trap for critical signals static void signal_handler(UNUSED_PARAM int signo) { // report I/O error condition exitcode = ERR_IO; } #if !ENABLE_FEATURE_CHAT_IMPLICIT_CR #define unescape(s, nocr) unescape(s) #endif static size_t unescape(char *s, int *nocr) { char *start = s; char *p = s; while (*s) { char c = *s; // do we need special processing? // standard escapes + \s for space and \N for \0 // \c inhibits terminating \r for commands and is noop for expects if ('\\' == c) { c = *++s; if (c) { #if ENABLE_FEATURE_CHAT_IMPLICIT_CR if ('c' == c) { *nocr = 1; goto next; } #endif if ('N' == c) { c = '\0'; } else if ('s' == c) { c = ' '; #if ENABLE_FEATURE_CHAT_NOFAIL // unescape leading dash only // TODO: and only for expect, not command string } else if ('-' == c && (start + 1 == s)) { //c = '-'; #endif } else { c = bb_process_escape_sequence((const char **)&s); s--; } } // ^A becomes \001, ^B -- \002 and so on... } else if ('^' == c) { c = *++s-'@'; } // put unescaped char *p++ = c; #if ENABLE_FEATURE_CHAT_IMPLICIT_CR next: #endif // next char s++; } *p = '\0'; return p - start; } int chat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int chat_main(int argc UNUSED_PARAM, char **argv) { int record_fd = -1; bool echo = 0; // collection of device replies which cause unconditional termination llist_t *aborts = NULL; // inactivity period int timeout = DEFAULT_CHAT_TIMEOUT; // maximum length of abort string #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN size_t max_abort_len = 0; #else #define max_abort_len MAX_ABORT_LEN #endif #if ENABLE_FEATURE_CHAT_TTY_HIFI struct termios tio0, tio; #endif // directive names enum { DIR_HANGUP = 0, DIR_ABORT, #if ENABLE_FEATURE_CHAT_CLR_ABORT DIR_CLR_ABORT, #endif DIR_TIMEOUT, DIR_ECHO, DIR_SAY, DIR_RECORD, }; // make x* functions fail with correct exitcode xfunc_error_retval = ERR_IO; // trap vanilla signals to prevent process from being killed suddenly bb_signals(0 + (1 << SIGHUP) + (1 << SIGINT) + (1 << SIGTERM) + (1 << SIGPIPE) , signal_handler); #if ENABLE_FEATURE_CHAT_TTY_HIFI tcgetattr(STDIN_FILENO, &tio); tio0 = tio; cfmakeraw(&tio); tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio); #endif #if ENABLE_FEATURE_CHAT_SWALLOW_OPTS getopt32(argv, "vVsSE"); argv += optind; #else argv++; // goto first arg #endif // handle chat expect-send pairs while (*argv) { // directive given? process it int key = index_in_strings( "HANGUP\0" "ABORT\0" #if ENABLE_FEATURE_CHAT_CLR_ABORT "CLR_ABORT\0" #endif "TIMEOUT\0" "ECHO\0" "SAY\0" "RECORD\0" , *argv ); if (key >= 0) { // cache directive value char *arg = *++argv; // OFF -> 0, anything else -> 1 bool onoff = (0 != strcmp("OFF", arg)); // process directive if (DIR_HANGUP == key) { // turn SIGHUP on/off signal(SIGHUP, onoff ? signal_handler : SIG_IGN); } else if (DIR_ABORT == key) { // append the string to abort conditions #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN size_t len = strlen(arg); if (len > max_abort_len) max_abort_len = len; #endif llist_add_to_end(&aborts, arg); #if ENABLE_FEATURE_CHAT_CLR_ABORT } else if (DIR_CLR_ABORT == key) { llist_t *l; // remove the string from abort conditions // N.B. gotta refresh maximum length too... # if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN max_abort_len = 0; # endif for (l = aborts; l; l = l->link) { # if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN size_t len = strlen(l->data); # endif if (strcmp(arg, l->data) == 0) { llist_unlink(&aborts, l); continue; } # if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN if (len > max_abort_len) max_abort_len = len; # endif } #endif } else if (DIR_TIMEOUT == key) { // set new timeout // -1 means OFF timeout = atoi(arg) * 1000; // 0 means default // >0 means value in msecs if (!timeout) timeout = DEFAULT_CHAT_TIMEOUT; } else if (DIR_ECHO == key) { // turn echo on/off // N.B. echo means dumping device input/output to stderr echo = onoff; } else if (DIR_RECORD == key) { // turn record on/off // N.B. record means dumping device input to a file // close previous record_fd if (record_fd > 0) close(record_fd); // N.B. do we have to die here on open error? record_fd = (onoff) ? xopen(arg, O_WRONLY|O_CREAT|O_TRUNC) : -1; } else if (DIR_SAY == key) { // just print argument verbatim // TODO: should we use full_write() to avoid unistd/stdio conflict? bb_error_msg("%s", arg); } // next, please! argv++; // ordinary expect-send pair! } else { //----------------------- // do expect //----------------------- int expect_len; size_t buf_len = 0; size_t max_len = max_abort_len; struct pollfd pfd; #if ENABLE_FEATURE_CHAT_NOFAIL int nofail = 0; #endif char *expect = *argv++; // sanity check: shall we really expect something? if (!expect) goto expect_done; #if ENABLE_FEATURE_CHAT_NOFAIL // if expect starts with - if ('-' == *expect) { // swallow - expect++; // and enter nofail mode nofail++; } #endif #ifdef ___TEST___BUF___ // test behaviour with a small buffer # undef COMMON_BUFSIZE # define COMMON_BUFSIZE 6 #endif // expand escape sequences in expect expect_len = unescape(expect, &expect_len /*dummy*/); if (expect_len > max_len) max_len = expect_len; // sanity check: // we should expect more than nothing but not more than input buffer // TODO: later we'll get rid of fixed-size buffer if (!expect_len) goto expect_done; if (max_len >= COMMON_BUFSIZE) { exitcode = ERR_MEM; goto expect_done; } // get reply pfd.fd = STDIN_FILENO; pfd.events = POLLIN; while (!exitcode && poll(&pfd, 1, timeout) > 0 && (pfd.revents & POLLIN) ) { #define buf bb_common_bufsiz1 llist_t *l; ssize_t delta; // read next char from device if (safe_read(STDIN_FILENO, buf+buf_len, 1) > 0) { // dump device input if RECORD fname if (record_fd > 0) { full_write(record_fd, buf+buf_len, 1); } // dump device input if ECHO ON if (echo > 0) { // if (buf[buf_len] < ' ') { // full_write(STDERR_FILENO, "^", 1); // buf[buf_len] += '@'; // } full_write(STDERR_FILENO, buf+buf_len, 1); } buf_len++; // move input frame if we've reached higher bound if (buf_len > COMMON_BUFSIZE) { memmove(buf, buf+buf_len-max_len, max_len); buf_len = max_len; } } // N.B. rule of thumb: values being looked for can // be found only at the end of input buffer // this allows to get rid of strstr() and memmem() // TODO: make expect and abort strings processed uniformly // abort condition is met? -> bail out for (l = aborts, exitcode = ERR_ABORT; l; l = l->link, ++exitcode) { size_t len = strlen(l->data); delta = buf_len-len; if (delta >= 0 && !memcmp(buf+delta, l->data, len)) goto expect_done; } exitcode = ERR_OK; // expected reply received? -> goto next command delta = buf_len - expect_len; if (delta >= 0 && !memcmp(buf+delta, expect, expect_len)) goto expect_done; #undef buf } /* while (have data) */ // device timed out or unexpected reply received exitcode = ERR_TIMEOUT; expect_done: #if ENABLE_FEATURE_CHAT_NOFAIL // on success and when in nofail mode // we should skip following subsend-subexpect pairs if (nofail) { if (!exitcode) { // find last send before non-dashed expect while (*argv && argv[1] && '-' == argv[1][0]) argv += 2; // skip the pair // N.B. do we really need this?! if (!*argv++ || !*argv++) break; } // nofail mode also clears all but IO errors (or signals) if (ERR_IO != exitcode) exitcode = ERR_OK; } #endif // bail out unless we expected successfully if (exitcode) break; //----------------------- // do send //----------------------- if (*argv) { #if ENABLE_FEATURE_CHAT_IMPLICIT_CR int nocr = 0; // inhibit terminating command with \r #endif char *loaded = NULL; // loaded command size_t len; char *buf = *argv++; // if command starts with @ // load "real" command from file named after @ if ('@' == *buf) { // skip the @ and any following white-space trim(++buf); buf = loaded = xmalloc_xopen_read_close(buf, NULL); } // expand escape sequences in command len = unescape(buf, &nocr); // send command alarm(timeout); pfd.fd = STDOUT_FILENO; pfd.events = POLLOUT; while (len && !exitcode && poll(&pfd, 1, -1) > 0 && (pfd.revents & POLLOUT) ) { #if ENABLE_FEATURE_CHAT_SEND_ESCAPES // "\\d" means 1 sec delay, "\\p" means 0.01 sec delay // "\\K" means send BREAK char c = *buf; if ('\\' == c) { c = *++buf; if ('d' == c) { sleep(1); len--; continue; } if ('p' == c) { usleep(10000); len--; continue; } if ('K' == c) { tcsendbreak(STDOUT_FILENO, 0); len--; continue; } buf--; } if (safe_write(STDOUT_FILENO, buf, 1) != 1) break; len--; buf++; #else len -= full_write(STDOUT_FILENO, buf, len); #endif } /* while (can write) */ alarm(0); // report I/O error if there still exists at least one non-sent char if (len) exitcode = ERR_IO; // free loaded command (if any) if (loaded) free(loaded); #if ENABLE_FEATURE_CHAT_IMPLICIT_CR // or terminate command with \r (if not inhibited) else if (!nocr) xwrite(STDOUT_FILENO, "\r", 1); #endif // bail out unless we sent command successfully if (exitcode) break; } /* if (*argv) */ } } /* while (*argv) */ #if ENABLE_FEATURE_CHAT_TTY_HIFI tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0); #endif return exitcode; }