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/*
** SWISH++
** ext_proc.c
**
** Copyright (C) 1998 Paul J. Lucas
**
** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
// standard
#include <cstdlib>
#include <sys/wait.h>
#include <unistd.h>
// local
#include "config.h"
#include "ext_proc.h"
#ifndef PJL_NO_NAMESPACES
using namespace std;
#endif
extern char const *me;
//*****************************************************************************
//
// SYNOPSIS
//
ext_proc_map::ext_proc_map()
//
// DESCRIPTION
//
// Construct (initialize) an ext_proc_map. The entries in
// ext_proc_table[] MUST be full paths.
//
// SEE ALSO
//
// extract.c do_file()
//
//*****************************************************************************
{
struct ext_proc {
char const *extension;
char const *undo;
char const *redo;
};
static ext_proc const ext_proc_table[] = {
"Z", "/bin/uncompress", "/usr/bin/compress",
"gz", "/bin/gunzip", "/bin/gzip",
"bz2", "/usr/bin/bunzip2", "/usr/bin/bzip2",
0
};
for ( register ext_proc const *e = ext_proc_table; e->extension; ++e )
map_[ e->extension ] = value_type( e->undo, e->redo );
}
//*****************************************************************************
//
// SYNOPSIS
//
bool process_file( char const *path_name, char const *file_name )
//
// DESCRIPTION
//
// Process a file with another command by forking, execing, and waiting
// for it to complete.
//
// RETURN VALUE
//
// Returns true only if the file was processed successfully.
//
// SEE ALSO
//
// exec(2), fork(2), wait(2), wstat(5)
//
//*****************************************************************************
{
static pid_t const pid_error = STATIC_CAST( pid_t )( -1 );
pid_t child_pid;
int attempt_count = 0;
while ( ( child_pid = ::fork() ) == pid_error ) {
//
// Try to fork a few times before giving up in case the system
// is temporarily busy.
//
if ( ++attempt_count > Fork_Attempts ) {
cerr << me << ": could not fork" << endl;
::exit( 2 );
}
::sleep( Fork_Sleep );
}
if ( !child_pid ) { // child process
::execl( path_name, path_name, file_name, 0 );
cerr << me << ": can not exec " << path_name << endl;
::exit( 3 );
}
int child_stat;
if ( ::wait( &child_stat ) == pid_error ) {
cerr << me << ": error waiting for child process" << endl;
::exit( 4 );
}
if ( WIFEXITED( child_stat ) && WEXITSTATUS( child_stat ) ) {
cerr << me << ": child process terminated abnormally" << endl;
::exit( 5 );
}
return true;
}
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