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/** \file osxhelp.c
* use OSX Help system
*/
/* XTrkCad - Model Railroad CAD
* Copyright (C) 2015 Martin Fischer
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include "gtkint.h"
#include "i18n.h"
#define HELPCOMMANDPIPE "/tmp/helppipe"
#define EXITCOMMAND "##exit##"
#define HELPERPROGRAM "helphelper"
static pid_t pidOfChild;
static int handleOfPipe;
extern char *wExecutableName;
/**
* Create the fully qualified filename for the help helper
*
* \param parent IN path and filename of parent process
* \return filename for the child process
*/
static
char *ChildProgramFile(char *parentProgram)
{
char *startOfFilename;
char *childProgram;
childProgram = malloc(strlen(parentProgram)+ sizeof(HELPERPROGRAM) + 1);
strcpy(childProgram, parentProgram);
startOfFilename = strrchr(childProgram, '/');
strcpy(startOfFilename + 1, HELPERPROGRAM);
return (childProgram);
}
/**
* Invoke the help system to display help for <topic>.
*
* \param topic IN topic string
*/
void wHelp(const char * topic)
{
pid_t newPid;
int len;
int status;
const char html[] = ".html";
char *page;
// check whether child already exists
if (pidOfChild != 0) {
if (waitpid(pidOfChild, &status, WNOHANG) > 0) {
// child exited -> clean up
close(handleOfPipe);
unlink(HELPCOMMANDPIPE);
handleOfPipe = 0;
pidOfChild = 0; // child exited
}
}
// (re)start child
if (pidOfChild == 0) {
mkfifo(HELPCOMMANDPIPE, 0666);
newPid = fork(); /* New process starts here */
if (newPid > 0) {
pidOfChild = newPid;
} else if (newPid == 0) {
char *child = ChildProgramFile(wExecutableName);
if (execlp(child, child, NULL) < 0) { /* never normally returns */
exit(8);
}
free(child);
} else { /* -1 signifies fork failure */
pidOfChild = 0;
return;
}
}
if (!handleOfPipe) {
handleOfPipe = open(HELPCOMMANDPIPE, O_WRONLY);
if (handleOfPipe < 0) {
kill(pidOfChild, SIGKILL); /* tidy up on next call */
}
}
page = malloc(strlen(topic) + strlen(html) + 1);
if (!page) {
return;
}
strcpy(page, topic);
strcat(page, html);
len = strlen(page);
write(handleOfPipe, &len, sizeof(int));
write(handleOfPipe, page, strlen(page)+1);
free(page);
}
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