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slattach: code shrink, better --help text

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function                                             old     new   delta
tcsetattr_serial_or_warn                               -      34     +34
static.int_N_SLIP                                      -       4      +4
restore_state_and_exit                               123     117      -6
packed_usage                                       31774   31747     -27
set_termios_state_or_warn                             42       -     -42
slattach_main                                        673     624     -49
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 0/3 up/down: 38/-124)           Total: -86 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2017-08-06 17:14:09 +02:00
parent a759b22c29
commit 2262746e2b
3 changed files with 68 additions and 107 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
NOFORK_NOEXEC.lst
View File

@ -78,7 +78,7 @@ conspy - interactive, longterm
cp - noexec. runner
cpio - runner
crond - daemon
crontab 0 leaks: open+xasprintf
crontab - longterm (runs $EDITOR), leaks: open+xasprintf
cryptpw - noexec. changes state: with --password-fd=N, moves N to stdin
cttyhack - noexec. spawner
cut - noexec. runner
@ -311,7 +311,7 @@ setkeycodes
setlogcons
setpriv - spawner, changes state, let's play safe and not be noexec
setserial
setsid - spawner, uses fork_or_rexec() [not audted to work in noexec], let's play safe and not be noexec
setsid - spawner, uses fork_or_rexec() [not audited to work in noexec], let's play safe and not be noexec
setuidgid - noexec. spawner
sha1sum - noexec. runner
sha256sum - noexec. runner
@ -320,7 +320,7 @@ sha512sum - noexec. runner
showkey - interactive, longterm
shred - runner
shuf - noexec. runner
slattach
slattach - longterm (may sleep forever), uses bb_common_bufsiz1
sleep - runner, longterm
smemcap - runner
softlimit - noexec. spawner

2
libbb/xfuncs.c
View File

@ -313,7 +313,7 @@ int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
int FAST_FUNC set_termios_to_raw(int fd, struct termios *oldterm, int flags)
{
//TODO: lineedit, microcom and less might be adapted to use this too:
//TODO: lineedit, microcom, slattach, less might be adapted to use this too:
// grep for "tcsetattr"
struct termios newterm;

167
networking/slattach.c
View File

@ -17,23 +17,23 @@
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: slattach is a small utility to attach network interfaces to serial
//config: lines.
//config: slattach configures serial line as SLIP network interface.
//applet:IF_SLATTACH(APPLET(slattach, BB_DIR_SBIN, BB_SUID_DROP))
/* shouldn't be NOEXEC: may sleep indefinitely */
//kbuild:lib-$(CONFIG_SLATTACH) += slattach.o
//usage:#define slattach_trivial_usage
//usage: "[-cehmLF] [-s SPEED] [-p PROTOCOL] DEVICE"
//usage: "[-ehmLF] [-c SCRIPT] [-s BAUD] [-p PROTOCOL] SERIAL_DEVICE"
//usage:#define slattach_full_usage "\n\n"
//usage: "Attach network interface(s) to serial line(s)\n"
//usage: "\n -p PROT Set protocol (slip, cslip, slip6, clisp6 or adaptive)"
//usage: "\n -s SPD Set line speed"
//usage: "\n -e Exit after initializing device"
//usage: "\n -h Exit when the carrier is lost"
//usage: "\n -c PROG Run PROG when the line is hung up"
//usage: "\n -m Do NOT initialize the line in raw 8 bits mode"
//usage: "Configure serial line as SLIP network interface\n"
//usage: "\n -p PROT Protocol: slip, cslip (default), slip6, clisp6, adaptive"
//usage: "\n -s BAUD Line speed"
//usage: "\n -e Exit after initialization"
//usage: "\n -h Exit if carrier is lost (else never exits)"
//usage: "\n -c PROG Run PROG on carrier loss"
//usage: "\n -m Do NOT set raw 8bit mode"
//usage: "\n -L Enable 3-wire operation"
//usage: "\n -F Disable RTS/CTS flow control"
@ -42,103 +42,53 @@
#include "libiproute/utils.h" /* invarg_1_to_2() */
struct globals {
int handle;
int saved_disc;
struct termios saved_state;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define handle (G.handle )
#define saved_disc (G.saved_disc )
#define saved_state (G.saved_state )
#define INIT_G() do { setup_common_bufsiz(); } while (0)
#define serial_fd 3
/*
* Save tty state and line discipline
*
* It is fine here to bail out on errors, since we haven modified anything yet
*/
static void save_state(void)
{
/* Save line status */
if (tcgetattr(handle, &saved_state) < 0)
bb_perror_msg_and_die("get state");
/* Save line discipline */
xioctl(handle, TIOCGETD, &saved_disc);
}
static int set_termios_state_or_warn(struct termios *state)
static int tcsetattr_serial_or_warn(struct termios *state)
{
int ret;
ret = tcsetattr(handle, TCSANOW, state);
if (ret < 0) {
bb_perror_msg("set state");
ret = tcsetattr(serial_fd, TCSANOW, state);
if (ret != 0) {
bb_perror_msg("tcsetattr");
return 1; /* used as exitcode */
}
return 0;
return ret; /* 0 */
}
/*
* Restore state and line discipline for ALL managed ttys
*
* Restoring ALL managed ttys is the only way to have a single
* hangup delay.
*
* Go on after errors: we want to restore as many controlled ttys
* as possible.
*/
static void restore_state_and_exit(int exitcode) NORETURN;
static void restore_state_and_exit(int exitcode)
{
struct termios state;
/* Restore line discipline */
if (ioctl_or_warn(handle, TIOCSETD, &saved_disc) < 0) {
if (ioctl_or_warn(serial_fd, TIOCSETD, &G.saved_disc)) {
exitcode = 1;
}
/* Hangup */
memcpy(&state, &saved_state, sizeof(state));
memcpy(&state, &G.saved_state, sizeof(state));
cfsetispeed(&state, B0);
cfsetospeed(&state, B0);
if (set_termios_state_or_warn(&state))
exitcode = 1;
exitcode |= tcsetattr_serial_or_warn(&state);
sleep(1);
/* Restore line status */
if (set_termios_state_or_warn(&saved_state))
if (tcsetattr_serial_or_warn(&G.saved_state))
exit(EXIT_FAILURE);
if (ENABLE_FEATURE_CLEAN_UP)
close(handle);
close(serial_fd);
exit(exitcode);
}
/*
* Set tty state, line discipline and encapsulation
*/
static void set_state(struct termios *state, int encap)
{
int disc;
/* Set line status */
if (set_termios_state_or_warn(state))
goto bad;
/* Set line discliple (N_SLIP always) */
disc = N_SLIP;
if (ioctl_or_warn(handle, TIOCSETD, &disc) < 0) {
goto bad;
}
/* Set encapsulation (SLIP, CSLIP, etc) */
if (ioctl_or_warn(handle, SIOCSIFENCAP, &encap) < 0) {
bad:
restore_state_and_exit(EXIT_FAILURE);
}
}
static void sig_handler(int signo UNUSED_PARAM)
{
restore_state_and_exit(EXIT_SUCCESS);
@ -155,13 +105,14 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
"cslip6\0" /* 3 */
"adaptive\0" /* 8 */
;
static const int int_N_SLIP = N_SLIP;
int i, encap, opt;
int encap, opt, fd;
struct termios state;
const char *proto = "cslip";
const char *extcmd; /* Command to execute after hangup */
const char *baud_str;
int baud_code = -1; /* Line baud rate (system code) */
int baud_code = baud_code; /* for compiler */
enum {
OPT_p_proto = 1 << 0,
@ -177,15 +128,12 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
INIT_G();
/* Parse command line options */
opt_complementary = "=1";
opt = getopt32(argv, "p:s:c:ehmLF", &proto, &baud_str, &extcmd);
/*argc -= optind;*/
argv += optind;
if (!*argv)
bb_show_usage();
encap = index_in_strings(proto_names, proto);
if (encap < 0)
invarg_1_to_2(proto, "protocol");
if (encap > 3)
@ -198,6 +146,22 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
invarg_1_to_2(baud_str, "baud rate");
}
/* Open tty */
fd = open(*argv, O_RDWR | O_NDELAY);
if (fd < 0) {
char *buf = concat_path_file("/dev", *argv);
fd = xopen(buf, O_RDWR | O_NDELAY);
/* maybe if (ENABLE_FEATURE_CLEAN_UP) ?? */
free(buf);
}
xmove_fd(fd, serial_fd);
/* Save current tty state */
if (tcgetattr(serial_fd, &G.saved_state) != 0)
bb_perror_msg_and_die("tcgetattr");
/* Save line discipline */
xioctl(serial_fd, TIOCGETD, &G.saved_disc);
/* Trap signals in order to restore tty states upon exit */
if (!(opt & OPT_e_quit)) {
bb_signals(0
@ -208,43 +172,37 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
, sig_handler);
}
/* Open tty */
handle = open(*argv, O_RDWR | O_NDELAY);
if (handle < 0) {
char *buf = concat_path_file("/dev", *argv);
handle = xopen(buf, O_RDWR | O_NDELAY);
/* maybe if (ENABLE_FEATURE_CLEAN_UP) ?? */
free(buf);
}
/* Save current tty state */
save_state();
/* Configure tty */
memcpy(&state, &saved_state, sizeof(state));
memcpy(&state, &G.saved_state, sizeof(state));
if (!(opt & OPT_m_nonraw)) { /* raw not suppressed */
memset(&state.c_cc, 0, sizeof(state.c_cc));
state.c_cc[VMIN] = 1;
state.c_iflag = IGNBRK | IGNPAR;
state.c_oflag = 0;
state.c_lflag = 0;
/*state.c_oflag = 0;*/
/*state.c_lflag = 0;*/
state.c_cflag = CS8 | HUPCL | CREAD
| ((opt & OPT_L_local) ? CLOCAL : 0)
| ((opt & OPT_F_noflow) ? 0 : CRTSCTS);
cfsetispeed(&state, cfgetispeed(&saved_state));
cfsetospeed(&state, cfgetospeed(&saved_state));
cfsetispeed(&state, cfgetispeed(&G.saved_state));
cfsetospeed(&state, cfgetospeed(&G.saved_state));
}
if (opt & OPT_s_baud) {
cfsetispeed(&state, baud_code);
cfsetospeed(&state, baud_code);
}
set_state(&state, encap);
/* Set line status */
if (tcsetattr_serial_or_warn(&state))
goto bad;
/* Set line disclipline (N_SLIP always) */
if (ioctl_or_warn(serial_fd, TIOCSETD, (void*)&int_N_SLIP))
goto bad;
/* Set encapsulation (SLIP, CSLIP, etc) */
if (ioctl_or_warn(serial_fd, SIOCSIFENCAP, &encap))
goto bad;
/* Exit now if option -e was passed */
if (opt & OPT_e_quit)
return 0;
return EXIT_SUCCESS;
/* If we're not requested to watch, just keep descriptor open
* until we are killed */
@ -254,17 +212,20 @@ int slattach_main(int argc UNUSED_PARAM, char **argv)
/* Watch line for hangup */
while (1) {
if (ioctl(handle, TIOCMGET, &i) < 0 || !(i & TIOCM_CAR))
goto no_carrier;
int modem_stat;
if (ioctl(serial_fd, TIOCMGET, &modem_stat))
break;
if (!(modem_stat & TIOCM_CAR))
break;
sleep(15);
}
no_carrier:
/* Execute command on hangup */
if (opt & OPT_c_extcmd)
system(extcmd);
/* Restore states and exit */
restore_state_and_exit(EXIT_SUCCESS);
bad:
restore_state_and_exit(EXIT_FAILURE);
}