boinc/sched/sched_timezone.C

296 lines
7.7 KiB
C

// Berkeley Open Infrastructure for Network Computing
// http://boinc.berkeley.edu
// Copyright (C) 2005 University of California
//
// This is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation;
// either version 2.1 of the License, or (at your option) any later version.
//
// This software 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 Lesser General Public License for more details.
//
// To view the GNU Lesser General Public License visit
// http://www.gnu.org/copyleft/lesser.html
// or write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
// Scheduler code for directing a client to one of several
// download servers based on its time zone
#include "config.h"
#include <string>
#include <stdio.h>
#include <cstring>
#include "parse.h"
#include "server_types.h"
#include "sched_msgs.h"
#ifdef _USING_FCGI_
#include "fcgi_stdio.h"
#else
#define FCGI_ToFILE(x) (x)
#endif
typedef struct urltag {
int zone;
char name[124];
} URLTYPE;
// these global variables are needed to pass information into the
// compare function below.
//
static int tzone=0;
static int hostid=0;
// Evaluate differences between time-zone. Two time zones that differ
// by almost 24 hours are actually very close on the surface of the
// earth. This function finds the 'shortest way around'
//
static int compare(const void *x, const void *y) {
const URLTYPE *a=(const URLTYPE *)x;
const URLTYPE *b=(const URLTYPE *)y;
char longname[512];
const int twelve_hours = 12*3600;
int diffa = abs(tzone - (a->zone));
int diffb = abs(tzone - (b->zone));
if (diffa > twelve_hours) {
diffa = 2*twelve_hours-diffa;
}
if (diffb > twelve_hours) {
diffb = 2*twelve_hours-diffb;
}
if (diffa < diffb) {
return -1;
}
if (diffa > diffb) {
return +1;
}
// In order to ensure uniform distribution, we hash paths that are
// equidistant from the host's timezone in a way that gives a
// unique ordering for each host but which is effectively random
// between hosts.
//
sprintf(longname, "%s%d", a->name, hostid);
std::string sa = md5_string((const unsigned char *)longname, strlen((const char *)longname));
sprintf(longname, "%s%d", b->name, hostid);
std::string sb = md5_string((const unsigned char *)longname, strlen((const char *)longname));
int xa = strtol(sa.substr(1, 7).c_str(), 0, 16);
int xb = strtol(sb.substr(1, 7).c_str(), 0, 16);
if (xa<xb) {
return -1;
}
if (xa>xb) {
return 1;
}
return 0;
}
static URLTYPE *cached=NULL;
#define BLOCKSIZE 32
URLTYPE* read_download_list() {
FILE *fp;
int count=0;
int i;
if (cached) return cached;
if (!(fp=fopen("../download_servers", "r"))) {
log_messages.printf(MSG_CRITICAL,
"File ../download_servers not found or unreadable!\n"
);
return NULL;
}
// read in lines from file
while (1) {
// allocate memory in blocks
if ((count % BLOCKSIZE)==0) {
cached=(URLTYPE *)realloc(cached, (count+BLOCKSIZE)*sizeof(URLTYPE));
if (!cached) return NULL;
}
// read timezone offset and URL from file, and store in cache
// list
if (2==fscanf(FCGI_ToFILE(fp), "%d %s", &(cached[count].zone), cached[count].name)) {
count++;
} else {
// provide a null terminator so we don't need to keep
// another global variable for count.
//
cached[count].name[0]='\0';
break;
}
}
fclose(fp);
if (!count) {
log_messages.printf(MSG_CRITICAL,
"File ../download_servers contained no valid entries!\n"
"Format of this file is one or more lines containing:\n"
"TIMEZONE_OFFSET_IN_SEC http://some.url.path\n"
);
free(cached);
return NULL;
}
// sort URLs by distance from host timezone. See compare() above
// for details.
qsort(cached, count, sizeof(URLTYPE), compare);
log_messages.printf(MSG_DEBUG,
"Sorted list of URLs follows [host timezone: UTC%+d]\n",
tzone
);
for (i=0; i<count; i++) {
log_messages.printf(MSG_DEBUG,
"zone=%+06d url=%s\n", cached[i].zone, cached[i].name
);
}
return cached;
}
// return number of bytes written, or <0 to indicate an error
//
int make_download_list(char *buffer, char *path, int tz) {
char *start=buffer;
int i;
// global variable used in the compare() function
tzone=tz;
URLTYPE *serverlist=read_download_list();
if (!serverlist) return -1;
// print list of servers in sorted order.
// Space is to format them nicely
//
for (i=0; strlen(serverlist[i].name); i++) {
start+=sprintf(start, "%s<url>%s/%s</url>", i?"\n ":"", serverlist[i].name, path);
}
// make a second copy in the same order
//
for (i=0; strlen(serverlist[i].name); i++) {
start+=sprintf(start, "%s<url>%s/%s</url>", "\n ", serverlist[i].name, path);
}
return (start-buffer);
}
// returns zero on success, non-zero to indicate an error
//
int add_download_servers(char *old_xml, char *new_xml, int tz) {
char *p, *q, *r;
p=r=old_xml;
// search for next URL to do surgery on
while ((q=strstr(p, "<url>"))) {
char *s;
char path[1024];
int len = q-p;
strncpy(new_xml, p, len);
new_xml += len;
// locate next instance of </url>
//
if (!(r=strstr(q, "</url>"))) {
return 1;
}
r += strlen("</url>");
// parse out the URL
//
if (!parse_str(q, "<url>", path, 1024)) {
return 1;
}
// find start of 'download/'
//
if (!(s=strstr(path,"download/"))) {
return 1;
}
// insert new download list in place of the original one
//
len = make_download_list(new_xml, s, tz);
if (len<0) {
return 1;
}
new_xml += len;
// advance pointer to start looking for next <url> tag.
//
p=r;
}
strcpy(new_xml, r);
return 0;
}
// replace the download URL for apps with a list of
// multiple download servers.
//
void process_av_timezone(
SCHEDULER_REPLY& reply, APP_VERSION* avp, APP_VERSION& av2
) {
int retval;
// set these global variables, needed by the compare()
// function so that the download URL list can be sorted by timezone
//
tzone=reply.host.timezone;
hostid=reply.host.id;
retval = add_download_servers(avp->xml_doc, av2.xml_doc, reply.host.timezone);
if (retval) {
log_messages.printf(MSG_CRITICAL,
"add_download_servers(to APP version) failed\n"
);
// restore original WU!
av2=*avp;
}
}
// replace the download URL for WU files with a list of
// multiple download servers.
//
void process_wu_timezone(
SCHEDULER_REPLY& reply, WORKUNIT& wu2, WORKUNIT& wu3
) {
int retval;
tzone=reply.host.timezone;
hostid=reply.host.id;
retval = add_download_servers(wu2.xml_doc, wu3.xml_doc, reply.host.timezone);
if (retval) {
log_messages.printf(MSG_CRITICAL,
"add_download_servers(to WU) failed\n"
);
// restore original WU!
wu3=wu2;
}
}
const char *BOINC_RCSID_28b6ac7093 = "$Id$";