--- /dev/null
+/* 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 tarball for details.
+ */
+#include "libbb.h"
+
+/*
+#define ENABLE_FEATURE_CHAT_NOFAIL 1 // +126 bytes
+#define ENABLE_FEATURE_CHAT_TTY_HIFI 0 // + 70 bytes
+#define ENABLE_FEATURE_CHAT_IMPLICIT_CR 1 // + 44 bytes
+#define ENABLE_FEATURE_CHAT_SEND_ESCAPES 0 // +103 bytes
+#define ENABLE_FEATURE_CHAT_VAR_ABORT_LEN 0 // + 70 bytes
+#define ENABLE_FEATURE_CHAT_CLR_ABORT 0 // +113 bytes
+#define ENABLE_FEATURE_CHAT_SWALLOW_OPTS 0 // + 23 bytes
+*/
+
+// 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
+// N.B> 10 bytes for volatile. Why all these signals?!
+static /*volatile*/ smallint exitcode;
+
+// trap for critical signals
+static void signal_handler(ATTRIBUTE_UNUSED 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, char **argv)
+{
+// should we dump device output? to what fd? by default no.
+// this can be controlled later via ECHO {ON|OFF} chat directive
+// int echo_fd;
+ 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,
+ };
+
+ // 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"
+ , *argv
+ );
+ if (key >= 0) {
+ // cache directive value
+ char *arg = *++argv;
+ // ON -> 1, anything else -> 0
+ bool onoff = !strcmp("ON", 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) {
+ // 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 (llist_t *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)) {
+ 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 output
+ // from stdin (device) to stderr
+ echo = onoff;
+//TODO? echo_fd = onoff * STDERR_FILENO;
+//TODO? echo_fd = xopen(arg, O_WRONLY|O_CREAT|O_TRUNC);
+ } else if (DIR_SAY == key) {
+ // just print argument verbatim
+ fprintf(stderr, arg);
+ }
+ // next, please!
+ argv++;
+ // ordinary expect-send pair!
+ } else {
+ //-----------------------
+ // do expect
+ //-----------------------
+ size_t expect_len, 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 output if ECHO ON or RECORD fname
+//TODO? if (echo_fd > 0) {
+//TODO? full_write(echo_fd, buf+buf_len, 1);
+//TODO? }
+ if (echo > 0)
+ 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
+ }
+
+ // 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_open_read_close(buf, NULL);
+ }
+
+ // expand escape sequences in command
+ len = unescape(buf, &nocr);
+
+ // send command
+#if ENABLE_FEATURE_CHAT_SEND_ESCAPES
+ pfd.fd = STDOUT_FILENO;
+ pfd.events = POLLOUT;
+ while (len && !exitcode
+ && poll(&pfd, 1, timeout) > 0
+ && (pfd.revents & POLLOUT)
+ ) {
+ // ugly! ugly! ugly!
+ // gotta send char by char to achieve this!
+ // Brrr...
+ // "\\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;
+ } else if ('p' == c) {
+ usleep(10000);
+ len--;
+ continue;
+ } else if ('K' == c) {
+ tcsendbreak(STDOUT_FILENO, 0);
+ len--;
+ continue;
+ } else {
+ buf--;
+ }
+ }
+ if (safe_write(STDOUT_FILENO, buf, 1) > 0) {
+ len--;
+ buf++;
+ } else
+ break;
+ }
+#else
+// if (len) {
+ alarm(timeout);
+ len -= full_write(STDOUT_FILENO, buf, len);
+ alarm(0);
+// }
+#endif
+
+ // 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 ENABLE_FEATURE_CHAT_TTY_HIFI
+ tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
+#endif
+
+ return exitcode;
+}
projects / oweals / busybox.git / commitdiff