busybox/miscutils/microcom.c

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/* vi: set sw=4 ts=4: */
/*
* bare bones 'talk to modem' program - similar to 'cu -l $device'
* inspired by mgetty's microcom
*
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* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
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*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config MICROCOM
//config: bool "microcom (5.6 kb)"
//config: default y
//config: help
//config: The poor man's minicom utility for chatting with serial port devices.
//applet:IF_MICROCOM(APPLET(microcom, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_MICROCOM) += microcom.o
//usage:#define microcom_trivial_usage
//usage: "[-d DELAY] [-t TIMEOUT] [-s SPEED] [-X] TTY"
//usage:#define microcom_full_usage "\n\n"
//usage: "Copy bytes for stdin to TTY and from TTY to stdout\n"
//usage: "\n -d Wait up to DELAY ms for TTY output before sending every"
//usage: "\n next byte to it"
//usage: "\n -t Exit if both stdin and TTY are silent for TIMEOUT ms"
//usage: "\n -s Set serial line to SPEED"
//usage: "\n -X Disable special meaning of NUL and Ctrl-X from stdin"
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#include "libbb.h"
#include "common_bufsiz.h"
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// set raw tty mode
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static void xget1(int fd, struct termios *t, struct termios *oldt)
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{
get_termios_and_make_raw(fd, t, oldt, 0
| TERMIOS_CLEAR_ISIG /* ^C is ASCII char 3, not "interrupt me!" */
| TERMIOS_RAW_INPUT /* pass all chars verbatim, no special handling or translating CR->NL */
| TERMIOS_RAW_CRNL /* dont convert NL<->CR on output too */
);
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}
static int xset1(int fd, struct termios *tio, const char *device)
{
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int ret = tcsetattr(fd, TCSAFLUSH, tio);
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if (ret) {
bb_perror_msg("can't tcsetattr for %s", device);
}
return ret;
}
int microcom_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int microcom_main(int argc UNUSED_PARAM, char **argv)
{
int sfd;
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int nfd;
struct pollfd pfd[2];
struct termios tio0, tiosfd, tio;
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char *device_lock_file;
enum {
OPT_X = 1 << 0, // do not respect Ctrl-X, Ctrl-@
OPT_s = 1 << 1, // baudrate
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OPT_d = 1 << 2, // wait for device response, ms
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OPT_t = 1 << 3, // timeout, ms
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};
speed_t speed = 9600;
int delay = -1;
int timeout = -1;
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unsigned opts;
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// fetch options
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
opts = getopt32(argv, "^" "Xs:+d:+t:+" "\0" "=1",
&speed, &delay, &timeout
);
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// argc -= optind;
argv += optind;
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// try to create lock file in /var/lock
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device_lock_file = (char *)bb_basename(argv[0]);
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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) {
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// device already locked -> bail out
if (errno == EEXIST)
bb_perror_msg_and_die("can't create '%s'", device_lock_file);
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// can't create lock -> don't care
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if (ENABLE_FEATURE_CLEAN_UP)
free(device_lock_file);
device_lock_file = NULL;
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} else {
// %4d to make concurrent mgetty (if any) happy.
// Mgetty treats 4-bytes lock files as binary,
// not text, PID. Making 5+ char file. Brrr...
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fdprintf(sfd, "%4d\n", getpid());
close(sfd);
}
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// setup signals
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bb_signals(0
+ (1 << SIGHUP)
+ (1 << SIGINT)
+ (1 << SIGTERM)
+ (1 << SIGPIPE)
, record_signo);
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// error exit code if we fail to open the device
bb_got_signal = 1;
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// 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);
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// put device to "raw mode"
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xget1(sfd, &tio, &tiosfd);
// set device speed
cfsetspeed(&tio, tty_value_to_baud(speed));
if (xset1(sfd, &tio, argv[0]))
goto done;
// 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;
}
// main loop: check with poll(), then read/write bytes across
pfd[0].fd = sfd;
pfd[0].events = POLLIN;
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pfd[1].fd = STDIN_FILENO;
pfd[1].events = POLLIN;
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bb_got_signal = 0;
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nfd = 2;
// Not safe_poll: we want to exit on signal
while (!bb_got_signal && poll(pfd, nfd, timeout) > 0) {
if (nfd > 1 && pfd[1].revents) {
char c;
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// read from stdin -> write to device
if (safe_read(STDIN_FILENO, &c, 1) < 1) {
// don't poll stdin anymore if we got EOF/error
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nfd--;
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goto skip_write;
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}
// do we need special processing?
if (!(opts & OPT_X)) {
// ^@ sends Break
if (VINTR == c) {
tcsendbreak(sfd, 0);
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goto skip_write;
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}
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// ^X exits
if (24 == c)
break;
}
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write(sfd, &c, 1);
if (delay >= 0)
safe_poll(pfd, 1, delay);
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skip_write: ;
}
if (pfd[0].revents) {
ssize_t len;
#define iobuf bb_common_bufsiz1
setup_common_bufsiz();
// read from device -> write to stdout
len = safe_read(sfd, iobuf, COMMON_BUFSIZE);
if (len > 0)
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full_write(STDOUT_FILENO, iobuf, len);
else {
// EOF/error -> bail out
bb_got_signal = SIGHUP;
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break;
}
}
}
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// restore device mode
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tcsetattr(sfd, TCSAFLUSH, &tiosfd);
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if (isatty(STDIN_FILENO))
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tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
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done:
if (device_lock_file)
unlink(device_lock_file);
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return bb_got_signal;
}