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/*
* dmucs_hosts_file.cc: code to read the hosts-info configuration file.
*
* Copyright (C) 2005, 2006 Victor T. Norman
*
* 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 "dmucs.h"
#include "dmucs_hosts_file.h"
#include <fstream>
#include <iostream>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <exception>
#include <sys/stat.h>
DmucsHostsFile *DmucsHostsFile::instance_ = NULL;
DmucsHostsFile *DmucsHostsFile::getInstance(const std::string &file)
{
if (instance_ == NULL) {
instance_ = new DmucsHostsFile(file);
}
return instance_;
}
DmucsHostsFile::DmucsHostsFile(const std::string &hostsInfoFile) :
lastFileChangeTime_(0),
hostsInfoFile_(hostsInfoFile)
{
readFileIntoDb();
/* We know the file has changed since time 0 -- so just call this
to get the new time into lastFileChangeTime_. */
(void) hasFileChanged();
}
void
DmucsHostsFile::readFileIntoDb() const
{
db_.clear();
std::ifstream instr(hostsInfoFile_.c_str());
if (!instr) {
DMUCS_DEBUG((stderr, "Unable to open hosts-info file \"%s\"\n",
hostsInfoFile_.c_str()));
return;
}
for (int lineno = 1; ; lineno++) {
/*
* Each line is: machine-or-ipaddr numcpus power-index.
* Comment lines start with #, and these are skipped. Lines
* containing only whitespace are also skipped.
*/
char firstChar;
instr >> firstChar; // this will skip empty lines.
if (instr.eof()) {
break;
}
if (firstChar == '#') {
std::string junk;
std::getline(instr, junk);
continue;
} else if (! instr.good()) {
break;
} else {
instr.putback(firstChar);
}
std::string line;
std::getline(instr, line);
char machine[256];
int numcpus, powerIndex;
if (sscanf(line.c_str(), "%s %d %d", machine, &numcpus,
&powerIndex) != 3) {
std::cout << "Bad input in line " << lineno << " of file " <<
hostsInfoFile_ << std::endl;
break;
}
/*
* Convert the machine name into an ip address.
*/
unsigned long addr;
struct hostent *hostent;
if ((int)(addr = inet_addr(machine)) != -1) {
hostent = gethostbyaddr((char *)&addr, sizeof(addr), AF_INET);
} else {
hostent = gethostbyname(machine);
}
if (hostent == NULL) {
std::cout << "Could not get IP address for machine: " << machine <<
". Skipping." << std::endl;
continue;
}
struct in_addr in;
memcpy(&in.s_addr, hostent->h_addr_list[0], sizeof(in.s_addr));
/* Insert the info into the database of host info. */
host_info_db_t::value_type object(in.s_addr,
info_t(numcpus, powerIndex));
db_.insert(object);
}
}
void
DmucsHostsFile::getDataForHost(const struct in_addr &ipAddr, int *numCpus,
int *powerIndex) const
{
if (hasFileChanged()) {
readFileIntoDb();
}
/*
* Be default, we'll assume 1 CPU and a very slow one at that.
*/
*numCpus = 1;
*powerIndex = 1;
host_info_db_iter_t itr = db_.find(ipAddr.s_addr);
if (itr != db_.end()) {
*numCpus = itr->second.numCpus_;
*powerIndex = itr->second.powerIndex_;
}
}
/* If the file modification time has changed since the last time this
was called, then return true AND update lastFileChangeTime_ to the
new modification time. */
bool
DmucsHostsFile::hasFileChanged() const
{
struct stat st;
if (stat(hostsInfoFile_.c_str(), &st) != 0) {
return true; // assume the file has changed...
}
if (lastFileChangeTime_ != st.st_ctime) {
lastFileChangeTime_ = st.st_ctime;
return true;
}
return false;
}
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