/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 1996-2015. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
/*
* Module: to_erl.c
*
* This module implements a process that opens two specified FIFOs, one
* for reading and one for writing; reads from its stdin, and writes what
* it has read to the write FIF0; reads from the read FIFO, and writes to
* its stdout.
*
________ _________
| |--<-- pipe.r (fifo1) --<--| |
| to_erl | | run_erl | (parent)
|________|-->-- pipe.w (fifo2) -->--|_________|
^ master pty
|
| slave pty
____V____
| |
| "erl" | (child)
|_________|
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <dirent.h>
#include <signal.h>
#include <errno.h>
#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif
#include "run_erl.h"
#include "safe_string.h" /* strn_cpy, strn_catf, sn_printf, etc. */
#if defined(O_NONBLOCK)
# define DONT_BLOCK_PLEASE O_NONBLOCK
#else
# define DONT_BLOCK_PLEASE O_NDELAY
# if !defined(EAGAIN)
# define EAGAIN -3898734
# endif
#endif
#ifdef HAVE_STRERROR
# define STRERROR(x) strerror(x)
#else
# define STRERROR(x) ""
#endif
#define noDEBUG
#define PIPE_DIR "/tmp/"
#define PIPE_STUBNAME "erlang.pipe"
#define PIPE_STUBLEN strlen(PIPE_STUBNAME)
#ifdef DEBUG
#define STATUS(s) { fprintf(stderr, (s)); fflush(stderr); }
#else
#define STATUS(s)
#endif
#ifndef FILENAME_MAX
#define FILENAME_MAX 250
#endif
static struct termios tty_smode, tty_rmode;
static int tty_eof = 0;
static int recv_sig = 0;
static int protocol_ver = RUN_ERL_LO_VER; /* assume lowest to begin with */
static int write_all(int fd, const char* buf, int len);
static int window_size_seq(char* buf, size_t bufsz);
static int version_handshake(char* buf, int len, int wfd);
#ifdef DEBUG
static void show_terminal_settings(struct termios *);
#endif
static void handle_ctrlc(int sig)
{
/* Reinstall the handler, and signal break flag */
signal(SIGINT,handle_ctrlc);
recv_sig = SIGINT;
}
static void handle_sigwinch(int sig)
{
recv_sig = SIGWINCH;
}
static void usage(char *pname)
{
fprintf(stderr, "Usage: %s [-h|-F] [pipe_name|pipe_dir/]\n", pname);
fprintf(stderr, "\t-h\tThis help text.\n");
fprintf(stderr, "\t-F\tForce connection even though pipe is locked by other to_erl process.\n");
}
int main(int argc, char **argv)
{
char FIFO1[FILENAME_MAX], FIFO2[FILENAME_MAX];
int i, len, wfd, rfd;
fd_set readfds;
char buf[BUFSIZ];
char pipename[FILENAME_MAX];
int pipeIx = 1;
int force_lock = 0;
int got_some = 0;
if (argc >= 2 && argv[1][0]=='-') {
switch (argv[1][1]) {
case 'h':
usage(argv[0]);
exit(1);
case 'F':
force_lock = 1;
break;
default:
fprintf(stderr,"Invalid option '%s'\n",argv[1]);
exit(1);
}
pipeIx = 2;
}
#ifdef DEBUG
fprintf(stderr, "%s: pid is : %d\n", argv[0], (int)getpid());
#endif
strn_cpy(pipename, sizeof(pipename),
(argv[pipeIx] ? argv[pipeIx] : PIPE_DIR));
if(*pipename && pipename[strlen(pipename)-1] == '/') {
/* The user wishes us to find a pipe name in the specified */
/* directory */
int highest_pipe_num = 0;
DIR *dirp;
struct dirent *direntp;
dirp = opendir(pipename);
if(!dirp) {
fprintf(stderr, "Can't access pipe directory %s: %s\n", pipename, strerror(errno));
exit(1);
}
/* Check the directory for existing pipes */
while((direntp=readdir(dirp)) != NULL) {
if(strncmp(direntp->d_name,PIPE_STUBNAME,PIPE_STUBLEN)==0) {
int num = atoi(direntp->d_name+PIPE_STUBLEN+1);
if(num > highest_pipe_num)
highest_pipe_num = num;
}
}
closedir(dirp);
strn_catf(pipename, sizeof(pipename), (highest_pipe_num?"%s.%d":"%s"),
PIPE_STUBNAME, highest_pipe_num);
} /* if */
/* read FIFO */
sn_printf(FIFO1,sizeof(FIFO1),"%s.r",pipename);
/* write FIFO */
sn_printf(FIFO2,sizeof(FIFO2),"%s.w",pipename);
/* Check that nobody is running to_erl on this pipe already */
if ((wfd = open (FIFO1, O_WRONLY|DONT_BLOCK_PLEASE, 0)) >= 0) {
/* Open as server succeeded -- to_erl is already running! */
close(wfd);
fprintf(stderr, "Another to_erl process already attached to pipe "
"%s.\n", pipename);
if (force_lock) {
fprintf(stderr, "But we proceed anyway by force (-F).\n");
}
else {
exit(1);
}
}
if ((rfd = open (FIFO1, O_RDONLY|DONT_BLOCK_PLEASE, 0)) < 0) {
#ifdef DEBUG
fprintf(stderr, "Could not open FIFO %s for reading.\n", FIFO1);
#endif
fprintf(stderr, "No running Erlang on pipe %s: %s\n", pipename, strerror(errno));
exit(1);
}
#ifdef DEBUG
fprintf(stderr, "to_erl: %s opened for reading\n", FIFO1);
#endif
if ((wfd = open (FIFO2, O_WRONLY|DONT_BLOCK_PLEASE, 0)) < 0) {
#ifdef DEBUG
fprintf(stderr, "Could not open FIFO %s for writing.\n", FIFO2);
#endif
fprintf(stderr, "No running Erlang on pipe %s: %s\n", pipename, strerror(errno));
close(rfd);
exit(1);
}
#ifdef DEBUG
fprintf(stderr, "to_erl: %s opened for writing\n", FIFO2);
#endif
fprintf(stderr, "Attaching to %s (^D to exit)\n\n", pipename);
/* Set break handler to our handler */
signal(SIGINT,handle_ctrlc);
/*
* Save the current state of the terminal, and set raw mode.
*/
if (tcgetattr(0, &tty_rmode) , 0) {
fprintf(stderr, "Cannot get terminals current mode\n");
exit(-1);
}
tty_smode = tty_rmode;
tty_eof = '\004'; /* Ctrl+D to exit */
#ifdef DEBUG
show_terminal_settings(&tty_rmode);
#endif
tty_smode.c_iflag =
1*BRKINT |/*Signal interrupt on break.*/
1*IGNPAR |/*Ignore characters with parity errors.*/
1*ISTRIP |/*Strip character.*/
0;
#if 0
0*IGNBRK |/*Ignore break condition.*/
0*PARMRK |/*Mark parity errors.*/
0*INPCK |/*Enable input parity check.*/
0*INLCR |/*Map NL to CR on input.*/
0*IGNCR |/*Ignore CR.*/
0*ICRNL |/*Map CR to NL on input.*/
0*IUCLC |/*Map upper-case to lower-case on input.*/
0*IXON |/*Enable start/stop output control.*/
0*IXANY |/*Enable any character to restart output.*/
0*IXOFF |/*Enable start/stop input control.*/
0*IMAXBEL|/*Echo BEL on input line too long.*/
#endif
tty_smode.c_oflag =
1*OPOST |/*Post-process output.*/
1*ONLCR |/*Map NL to CR-NL on output.*/
#ifdef XTABS
1*XTABS |/*Expand tabs to spaces. (Linux)*/
#endif
#ifdef OXTABS
1*OXTABS |/*Expand tabs to spaces. (FreeBSD)*/
#endif
#ifdef NL0
1*NL0 |/*Select newline delays*/
#endif
#ifdef CR0
1*CR0 |/*Select carriage-return delays*/
#endif
#ifdef TAB0
1*TAB0 |/*Select horizontal tab delays*/
#endif
#ifdef BS0
1*BS0 |/*Select backspace delays*/
#endif
#ifdef VT0
1*VT0 |/*Select vertical tab delays*/
#endif
#ifdef FF0
1*FF0 |/*Select form feed delays*/
#endif
0;
#if 0
0*OLCUC |/*Map lower case to upper on output.*/
0*OCRNL |/*Map CR to NL on output.*/
0*ONOCR |/*No CR output at column 0.*/
0*ONLRET |/*NL performs CR function.*/
0*OFILL |/*Use fill characters for delay.*/
0*OFDEL |/*Fill is DEL, else NULL.*/
0*NL1 |
0*CR1 |
0*CR2 |
0*CR3 |
0*TAB1 |
0*TAB2 |
0*TAB3 |/*Expand tabs to spaces.*/
0*BS1 |
0*VT1 |
0*FF1 |
#endif
/* JALI: removed setting the tty_smode.c_cflag flags, since this is not */
/* advisable if this is a *real* terminal, such as the console. In fact */
/* this may hang the entire machine, deep, deep down (signalling break */
/* or toggling the abort switch doesn't help) */
tty_smode.c_lflag =
0;
#if 0
0*ISIG |/*Enable signals.*/
0*ICANON |/*Canonical input (erase and kill processing).*/
0*XCASE |/*Canonical upper/lower presentation.*/
0*ECHO |/*Enable echo.*/
0*ECHOE |/*Echo erase character as BS-SP-BS.*/
0*ECHOK |/*Echo NL after kill character.*/
0*ECHONL |/*Echo NL.*/
0*NOFLSH |/*Disable flush after interrupt or quit.*/
0*TOSTOP |/*Send SIGTTOU for background output.*/
0*ECHOCTL|/*Echo control characters as ^char, delete as ^?.*/
0*ECHOPRT|/*Echo erase character as character erased.*/
0*ECHOKE |/*BS-SP-BS erase entire line on line kill.*/
0*FLUSHO |/*Output is being flushed.*/
0*PENDIN |/*Retype pending input at next read or input character.*/
0*IEXTEN |/*Enable extended (implementation-defined) functions.*/
#endif
tty_smode.c_cc[VMIN] =0;/* Note that VMIN is the same as VEOF! */
tty_smode.c_cc[VTIME] =0;/* Note that VTIME is the same as VEOL! */
tty_smode.c_cc[VINTR] =3;
tcsetattr(0, TCSADRAIN, &tty_smode);
#ifdef DEBUG
show_terminal_settings(&tty_smode);
#endif
/*
* "Write a ^L to the FIFO which causes the other end to redisplay
* the input line."
* This does not seem to work as was intended in old comment above.
* However, this control character is now (R12B-3) used by run_erl
* to trigger the version handshaking between to_erl and run_erl
* at the start of every new to_erl-session.
*/
if (write(wfd, "\014", 1) < 0) {
fprintf(stderr, "Error in writing ^L to FIFO.\n");
}
/*
* read and write
*/
while (1) {
FD_ZERO(&readfds);
FD_SET(0, &readfds);
FD_SET(rfd, &readfds);
if (select(rfd + 1, &readfds, NULL, NULL, NULL) < 0) {
if (recv_sig) {
FD_ZERO(&readfds);
}
else {
fprintf(stderr, "Error in select.\n");
break;
}
}
len = 0;
/*
* Read from terminal and write to FIFO
*/
if (recv_sig) {
switch (recv_sig) {
case SIGINT:
fprintf(stderr, "[Break]\n\r");
buf[0] = '\003';
len = 1;
break;
case SIGWINCH:
len = window_size_seq(buf,sizeof(buf));
break;
default:
fprintf(stderr,"Unexpected signal: %u\n",recv_sig);
}
recv_sig = 0;
}
else if (FD_ISSET(0, &readfds)) {
len = read(0, buf, sizeof(buf));
if (len <= 0) {
close(rfd);
close(wfd);
if (len < 0) {
fprintf(stderr, "Error in reading from stdin.\n");
} else {
fprintf(stderr, "[EOF]\n\r");
}
break;
}
/* check if there is an eof character in input */
for (i = 0; i < len && buf[i] != tty_eof; i++);
if (buf[i] == tty_eof) {
fprintf(stderr, "[Quit]\n\r");
break;
}
}
if (len) {
#ifdef DEBUG
if(write(1, buf, len));
#endif
if (write_all(wfd, buf, len) != len) {
fprintf(stderr, "Error in writing to FIFO.\n");
close(rfd);
close(wfd);
break;
}
STATUS("\" OK\r\n");
}
/*
* Read from FIFO, write to terminal.
*/
if (FD_ISSET(rfd, &readfds)) {
STATUS("FIFO read: ");
len = read(rfd, buf, BUFSIZ);
if (len < 0 && errno == EAGAIN) {
/*
* No data this time, but the writing end of the FIFO is still open.
* Do nothing.
*/
;
} else if (len <= 0) {
/*
* Either an error or end of file. In either case, break out
* of the loop.
*/
close(rfd);
close(wfd);
if (len < 0) {
fprintf(stderr, "Error in reading from FIFO.\n");
} else
fprintf(stderr, "[End]\n\r");
break;
} else {
if (!got_some) {
if ((len=version_handshake(buf,len,wfd)) < 0) {
close(rfd);
close(wfd);
break;
}
if (protocol_ver >= 1) {
/* Tell run_erl size of terminal window */
signal(SIGWINCH, handle_sigwinch);
raise(SIGWINCH);
}
got_some = 1;
}
/*
* We successfully read at least one character. Write what we got.
*/
STATUS("Terminal write: \"");
if (write_all(1, buf, len) != len) {
fprintf(stderr, "Error in writing to terminal.\n");
close(rfd);
close(wfd);
break;
}
STATUS("\" OK\r\n");
}
}
}
/*
* Reset terminal characterstics
* XXX
*/
tcsetattr(0, TCSADRAIN, &tty_rmode);
return 0;
}
/* Call write() until entire buffer has been written or error.
* Return len or -1.
*/
static int write_all(int fd, const char* buf, int len)
{
int left = len;
int written;
while (left) {
written = write(fd,buf,left);
if (written < 0) {
return -1;
}
left -= written;
buf += written;
}
return len;
}
static int window_size_seq(char* buf, size_t bufsz)
{
#ifdef TIOCGWINSZ
struct winsize ws;
static const char prefix[] = "\033_";
static const char suffix[] = "\033\\";
/* This Esc sequence is called "Application Program Command"
and seems suitable to use for our own customized stuff. */
if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == 0) {
int len = sn_printf(buf, bufsz, "%swinsize=%u,%u%s",
prefix, ws.ws_col, ws.ws_row, suffix);
return len;
}
#endif /* TIOCGWINSZ */
return 0;
}
/* to_erl run_erl
* | |
* |---------- '\014' -------->| (session start)
* | |
* |<---- "[run_erl v1-0]" ----| (version interval)
* | |
* |--- Esc_"version=1"Esc\ -->| (common version)
* | |
*/
static int version_handshake(char* buf, int len, int wfd)
{
unsigned re_high=0, re_low;
char *end = find_str(buf,len,"]\n");
if (end && sscanf(buf,"[run_erl v%u-%u",&re_high,&re_low)==2) {
char wbuf[30];
int wlen;
if (re_low > RUN_ERL_HI_VER || re_high < RUN_ERL_LO_VER) {
fprintf(stderr,"Incompatible versions: to_erl=v%u-%u run_erl=v%u-%u\n",
RUN_ERL_HI_VER, RUN_ERL_LO_VER, re_high, re_low);
return -1;
}
/* Choose highest common version */
protocol_ver = re_high < RUN_ERL_HI_VER ? re_high : RUN_ERL_HI_VER;
wlen = sn_printf(wbuf, sizeof(wbuf), "\033_version=%u\033\\",
protocol_ver);
if (write_all(wfd, wbuf, wlen) < 0) {
fprintf(stderr,"Failed to send version handshake\n");
return -1;
}
end += 2;
len -= (end-buf);
memmove(buf,end,len);
}
else { /* we assume old run_erl without version handshake */
protocol_ver = 0;
}
if (re_high != RUN_ERL_HI_VER) {
fprintf(stderr,"run_erl has different version, "
"using common protocol level %u\n", protocol_ver);
}
return len;
}
#ifdef DEBUG
#define S(x) ((x) > 0 ? 1 : 0)
static void show_terminal_settings(struct termios *t)
{
fprintf(stderr,"c_iflag:\n");
fprintf(stderr,"Signal interrupt on break: BRKINT %d\n", S(t->c_iflag & BRKINT));
fprintf(stderr,"Map CR to NL on input: ICRNL %d\n", S(t->c_iflag & ICRNL));
fprintf(stderr,"Ignore break condition: IGNBRK %d\n", S(t->c_iflag & IGNBRK));
fprintf(stderr,"Ignore CR: IGNCR %d\n", S(t->c_iflag & IGNCR));
fprintf(stderr,"Ignore char with par. err's: IGNPAR %d\n", S(t->c_iflag & IGNPAR));
fprintf(stderr,"Map NL to CR on input: INLCR %d\n", S(t->c_iflag & INLCR));
fprintf(stderr,"Enable input parity check: INPCK %d\n", S(t->c_iflag & INPCK));
fprintf(stderr,"Strip character ISTRIP %d\n", S(t->c_iflag & ISTRIP));
fprintf(stderr,"Enable start/stop input ctrl IXOFF %d\n", S(t->c_iflag & IXOFF));
fprintf(stderr,"ditto output ctrl IXON %d\n", S(t->c_iflag & IXON));
fprintf(stderr,"Mark parity errors PARMRK %d\n", S(t->c_iflag & PARMRK));
fprintf(stderr,"\n");
fprintf(stderr,"c_oflag:\n");
fprintf(stderr,"Perform output processing OPOST %d\n", S(t->c_oflag & OPOST));
fprintf(stderr,"\n");
fprintf(stderr,"c_cflag:\n");
fprintf(stderr,"Ignore modem status lines CLOCAL %d\n", S(t->c_cflag & CLOCAL));
fprintf(stderr,"\n");
fprintf(stderr,"c_local:\n");
fprintf(stderr,"Enable echo ECHO %d\n", S(t->c_lflag & ECHO));
fprintf(stderr,"\n");
fprintf(stderr,"c_cc:\n");
fprintf(stderr,"c_cc[VEOF] %d\n", t->c_cc[VEOF]);
}
#endif
