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/*
* axwrapper.c - Convert end-of-line sequences for non-AX.25 aware programs -
* version 1.1
*
* Copyright (C) 1996-2001 Tomi Manninen, OH2BNS, <tomi.manninen@hut.fi>.
*
* Compile with: gcc -Wall -O6 -o axwrapper axwrapper.c
*
* Usage: axwrapper [-p <paclen>] <filename> <argv[0]> ...
*
* Axwrapper first creates a pipe and then forks and execs the program
* <filename> with arguments given at the axwrapper command line.
* The parent process then sits and waits for any I/O to and from the
* user and converts any <CR>'s from user to <NL>'s and any <NL>'s from
* the program to <CR>'s. This is useful when starting non-AX.25 aware
* programs from ax25d.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/time.h>
#include <string.h>
#include <errno.h>
#define FLUSHTIMEOUT 500000 /* 0.5 sec */
#define PERROR(s) fprintf(stderr, "*** %s: %s\r", (s), strerror(errno))
#define USAGE() fputs("Usage: axwrapper [-p <paclen>] <filename> <argv[0]> ...\r", stderr)
static void convert_cr_lf(unsigned char *buf, int len)
{
while (len-- > 0) {
if (*buf == '\r') *buf = '\n';
buf++;
}
}
static void convert_lf_cr(unsigned char *buf, int len)
{
while (len-- > 0) {
if (*buf == '\n') *buf = '\r';
buf++;
}
}
int main(int argc, char **argv)
{
unsigned char buf[4096];
char *stdoutbuf;
int pipe_in[2];
int pipe_out[2];
int pipe_err[2];
int len;
int pid;
int paclen = 256;
fd_set fdset;
struct timeval tv;
while ((len = getopt(argc, argv, "p:")) != -1) {
switch (len) {
case 'p':
paclen = atoi(optarg);
break;
case ':':
case '?':
USAGE();
exit(1);
}
}
if (argc - optind < 2) {
USAGE();
exit(1);
}
stdoutbuf = malloc(paclen);
if (stdoutbuf == NULL) {
PERROR("axwrapper: malloc");
exit(1);
}
setvbuf(stdout, stdoutbuf, _IOFBF, paclen);
if (pipe(pipe_in) == -1) {
PERROR("axwrapper: pipe");
exit(1);
}
if (pipe(pipe_out) == -1) {
PERROR("axwrapper: pipe");
exit(1);
}
if (pipe(pipe_err) == -1) {
PERROR("axwrapper: pipe");
exit(1);
}
signal(SIGCHLD, SIG_IGN);
pid = fork();
if (pid == -1) {
/* fork error */
PERROR("axwrapper: fork");
exit(1);
}
if (pid == 0) {
/* child */
dup2(pipe_in[0], STDIN_FILENO);
close(pipe_in[1]);
dup2(pipe_out[1], STDOUT_FILENO);
close(pipe_out[0]);
dup2(pipe_err[1], STDERR_FILENO);
close(pipe_err[0]);
execve(argv[optind], argv + optind + 1, NULL);
/* execve() should not return */
perror("axwrapper: execve");
exit(1);
}
/* parent */
close(pipe_in[0]);
close(pipe_out[1]);
close(pipe_err[1]);
if (fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK) == -1) {
perror("axwrapper: fcntl");
exit(1);
}
if (fcntl(pipe_out[0], F_SETFL, O_NONBLOCK) == -1) {
perror("axwrapper: fcntl");
exit(1);
}
if (fcntl(pipe_err[0], F_SETFL, O_NONBLOCK) == -1) {
perror("axwrapper: fcntl");
exit(1);
}
while (1) {
FD_ZERO(&fdset);
int maxfd = -1;
FD_SET(STDIN_FILENO, &fdset);
if (STDIN_FILENO > maxfd)
maxfd = STDIN_FILENO + 1;
FD_SET(pipe_out[0], &fdset);
if (pipe_out[0] > maxfd)
maxfd = pipe_out[0] + 1;
FD_SET(pipe_err[0], &fdset);
if (pipe_err[0] > maxfd)
maxfd = pipe_err[0] + 1;
tv.tv_sec = 0;
tv.tv_usec = FLUSHTIMEOUT;
len = select(maxfd, &fdset, NULL, NULL, &tv);
if (len == -1) {
if (errno == EINTR)
continue;
perror("axwrapper: select");
exit(1);
}
if (len == 0) {
fflush(stdout);
}
if (FD_ISSET(STDIN_FILENO, &fdset)) {
len = read(STDIN_FILENO, buf, sizeof(buf));
if (len < 0 && errno != EAGAIN) {
perror("axwrapper: read");
break;
}
if (len == 0)
break;
convert_cr_lf(buf, len);
write(pipe_in[1], buf, len);
}
if (FD_ISSET(pipe_out[0], &fdset)) {
len = read(pipe_out[0], buf, sizeof(buf));
if (len < 0 && errno != EAGAIN) {
perror("axwrapper: read");
break;
}
if (len == 0)
break;
convert_lf_cr(buf, len);
fwrite(buf, 1, len, stdout);
}
if (FD_ISSET(pipe_err[0], &fdset)) {
len = read(pipe_err[0], buf, sizeof(buf));
if (len < 0 && errno != EAGAIN) {
perror("axwrapper: read");
break;
}
if (len == 0)
break;
convert_lf_cr(buf, len);
fwrite(buf, 1, len, stderr);
}
}
kill(pid, SIGTERM);
close(pipe_in[1]);
close(pipe_out[0]);
close(pipe_err[0]);
return 0;
}
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