/usr/bin/git-cache-proxy is in chiark-scripts 5.0.2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 | #!/usr/bin/perl -w
#
# git caching proxy
# Suitable only for exposing to semi-trusted clients: clients are not
# supposed to be able to take over the server. However, clients can
# probably deny service to each other because the current
# implementation is not very good at handling various out-of-course
# situations (notably, clients which are too slow).
# usage: run it on some port, and then clone or fetch
# "git://<realhost>:<realport>/<real-git-url>[ <options>]"
# where <real-git-url> is http://<host>/... or git://<host>/...
# and <options> is zero or more (whitespace-separated) of
# [<some-option>] will be ignored if not recognised
# {<some-option>} error if not recognised
# options currently known:
# fetch=must fail if the fetch/clone from upstream fails
# fetch=no just use what is in the cache
# fetch=try use what is in the cache if the fetch/clone fails
# timeout=<seconds> length of time to allow for fetch/clone
# example inetd.conf line:
# 9419 stream tcp nowait git-cache /usr/bin/git-cache-proxy git-cache-proxy
# you'll need to
# adduser git-cache
# mkdir /var/cache/git-cache-proxy
# chown git-cache /var/cache/git-cache-proxy
# git-cache-proxy
# Copyright 2010 Tony Finch
# Copyright 2013,2014 Ian Jackson
#
# git-cache-proxy is free software; you can redistribute it and/or
# modify them under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 3, or (at
# your option) any later version.
#
# git-cache-proxy 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, consult the Free Software Foundation's
# website at www.fsf.org, or the GNU Project website at www.gnu.org.
#
# (Some code taken from userv-utils's git-daemon.in and git-service.in
# which were written by Tony Finch <dot@dotat.at> and subsequently
# heavily modified by Ian Jackson <ijackson@chiark.greenend.org.uk>
# and were released under CC0 1.0. The whole program is now GPLv3+.)
use strict;
use warnings;
use POSIX;
use Socket;
use Sys::Syslog;
use Fcntl qw(:flock SEEK_SET);
use File::Path qw(remove_tree);
our $us = 'git-cache-proxy';
our $debug = 0;
our $housekeepingeverydays = 1;
our $treeexpiredays = 21;
our $fetchtimeout = 1800;
our $maxfetchtimeout = 3600;
our $cachedir = '/var/cache/git-cache-proxy';
our $housekeepingonly = 0;
#---------- error handling and logging ----------
# This is a bit fiddly, because we want to catch errors sent to stderr
# and dump them to syslog if we can, but only if we are running as an
# inetd service.
our $log; # filehandle (ref), or "1" meaning syslog
sub ntoa {
my $sockaddr = shift;
return ('(local)') unless defined $sockaddr;
my ($port,$addr) = sockaddr_in $sockaddr;
$addr = inet_ntoa $addr;
return ("[$addr]:$port",$addr,$port);
}
our ($client) = ntoa getpeername STDIN;
our ($server) = ntoa getsockname STDIN;
sub ensurelog () {
return if $log;
openlog $us, qw(pid), 'daemon';
$log = 1;
}
sub logm ($$) {
my ($pri, $msg) = @_;
return if $pri eq 'debug' && !$debug;
if ($client eq '(local)') {
print STDERR "$us: $pri: $msg\n" or die $!;
return;
}
ensurelog();
my $mainmsg = sprintf "%s-%s: %s", $server, $client, $msg;
if (ref $log) {
my $wholemsg = sprintf("%s [%d] %s: %s\n",
strftime("%Y-%m-%d %H:%M:%S Z", gmtime),
$$,
$pri eq 'err' ? 'error' : $pri,
$mainmsg);
print $log $wholemsg;
} else {
syslog $pri, "%s", "$pri $mainmsg";
}
}
if ($client ne '(local)') {
open STDERR, ">/dev/null" or exit 255;
open TEMPERR, "+>", undef or exit 255;
open STDERR, ">&TEMPERR" or exit 255;
}
END {
if ($client ne '(local)') {
if ($?) { logm 'crit', "crashing ($?)"; }
seek TEMPERR, 0, SEEK_SET;
while (<TEMPERR>) {
chomp;
logm 'crit', $_;
}
}
exit $?;
}
sub fail ($) {
my ($msg) = @_;
logm 'err', $msg;
exit 0;
}
sub gitfail ($) {
my ($msg) = @_;
close LOCK;
alarm 60;
logm 'notice', $msg;
my $gitmsg = "ERR $us: $msg";
$gitmsg = substr($gitmsg,0,65535); # just in case
printf "%04x%s", length($gitmsg)+4, $gitmsg;
flush STDOUT;
exit 0;
}
#---------- argument parsing ----------
for (;;) {
last unless @ARGV;
last unless $ARGV[0] =~ m/^-/;
$_ = shift @ARGV;
for (;;) {
last unless m/^-./;
if (s/^-H/-/) {
$housekeepingonly++;
} elsif (s/^-D/-/) {
$debug++;
} elsif (s/^-L(.*)$//) {
my $logfile = $_;
open STDERR, ">>", $logfile or fail "open $logfile: $!";
$log = \*STDERR;
} elsif (s/^-d(.*)$//) {
$cachedir = $1;
} elsif (s/^--( max-fetch-timeout
| fetch-timeout
| tree-expire-days
| housekeeping-interval-days
)=(\d+)$//x) {
my $vn = $1;
$vn =~ y/-//d;
die $vn unless defined ${ $::{$vn} };
${ $::{$vn} } = $2;
} else {
fail "bad usage: unknown option `$_'";
}
}
}
!@ARGV or fail "bad usage: no non-option arguments permitted";
#---------- utility functions ----------
sub lockfile ($$$) {
my ($fh, $fn, $flockmode) = @_;
my $what = $fn.(($flockmode & ~LOCK_NB) == LOCK_SH ? " (shared)" : "");
for (;;) {
close $fh;
open $fh, '+>', $fn or fail "open/create $fn for lock: $!";
logm 'debug', "lock $what: acquiring";
if (!flock $fh, $flockmode) {
if ($flockmode & LOCK_NB && $! == EWOULDBLOCK) {
return 0; # ok then
}
fail "lock $what: $!";
}
stat $fh or fail "stat opened $fn: $!";
my $fh_ino = ((stat _)[1]);
if (!stat $fn) {
$! == ENOENT or fail "stat $fn: $!";
next;
}
my $fn_ino = ((stat _)[1]);
if ($fn_ino == $fh_ino) {
logm 'debug', "lock $what: acquired";
return 1;
}
logm 'debug', "lock $what: deleted, need to loop again";
# oh dear
}
}
sub xread {
my $length = shift;
my $buffer = "";
while ($length > length $buffer) {
my $ret = sysread STDIN, $buffer, $length, length $buffer;
fail "expected $length bytes, got ".length $buffer
if defined $ret and $ret == 0;
fail "read: $!" if not defined $ret and $! != EINTR and $! != EAGAIN;
}
return $buffer;
}
#---------- main program ----------
chdir $cachedir or fail "chdir $cachedir: $!";
our ($service,$specpath,$spechost,$subdir);
our ($tmpd,$gitd,$lock);
our ($fetch,$url);
sub servinfo ($) {
my ($msg) = @_;
logm 'info', "service `$specpath': $msg";
}
sub readcommand () {
$SIG{ALRM} = sub { fail "timeout" };
alarm 30;
my $hex_len = xread 4;
fail "Bad hex in packet length" unless $hex_len =~ m|^[0-9a-fA-F]{4}$|;
my $line = xread -4 + hex $hex_len;
unless (($service,$specpath,$spechost) = $line =~
m|^(git-[a-z-]+) /*([!-~ ]+)\0host=([!-~]+)\0$|) {
$line =~ s|[^ -~]+| |g;
gitfail "unknown/unsupported instruction `$line'"
}
alarm 0;
$service eq 'git-upload-pack'
or gitfail "unknown/unsupported service `$service'";
$fetch = 2; # 0:don't; 1:try; 2:force
$url = $specpath;
while ($url =~ s#\s+(\[)([^][{}]+)\]$## ||
$url =~ s#\s+(\{)([^][{}]+)\}$##) {
$_ = $2;
my $must = $1 eq '{';
if (m/^fetch=try$/) {
$fetch = 1;
} elsif (m/^fetch=no$/) {
$fetch = 0;
} elsif (m/^fetch=must$/) {
$fetch = 2; # the default
} elsif (m/^timeout=(\d+)$/ && $1 >= 1) {
$fetchtimeout = $1 <= $maxfetchtimeout ? $1 : $maxfetchtimeout;
} elsif ($must) {
gitfail "unknown/unsupported option `$_'";
}
}
$url =~ m{^(?:https?|git)://[-.0-9a-z]+/}
or gitfail "unknown/unsupported url scheme or format `$url'";
$subdir = $url;
$subdir =~ s|\\|\\\\|g;
$subdir =~ s|,|\\,|g;
$subdir =~ s|/|,|g;
$tmpd= "$subdir\\.tmp";
$gitd= "$subdir\\.git";
$lock = "$subdir\\.lock";
servinfo "locking";
}
sub clonefetch () {
lockfile \*LOCK, $lock, LOCK_EX;
my $exists = lstat $gitd;
$exists or $!==ENOENT or fail "lstat $gitd: $!";
our $fetchfail = '';
if ($fetch) {
our @cmd;
if (!$exists) {
system qw(rm -rf --), $tmpd;
@cmd = (qw(git clone -q --mirror), $url, $tmpd);
servinfo "cloning";
} else {
@cmd = (qw(git remote update --prune));
servinfo "fetching";
}
my $cmd = "@cmd[0..1]";
my $child = open FETCHERR, "-|";
defined $child or fail "fork: $!";
if (!$child) {
if ($exists) {
chdir $gitd or fail "chdir $gitd: $!";
}
setpgrp or fail "setpgrp: $!";
open STDERR, ">&STDOUT" or fail "redirect stderr: $!";
exec @cmd or fail "exec $cmd[0]: $!";
}
my $fetcherr = '';
my $timedout = 0;
{
local $SIG{ALRM} = sub {
servinfo "fetch/clone timeout";
$timedout=1; kill 9, -$child;
};
alarm($fetchtimeout);
$!=0; { local $/=undef; $fetcherr = <FETCHERR>; }
!FETCHERR->error or fail "read pipe from fetch/clone: $!";
alarm(10);
}
kill -9, $child or fail "kill fetch/clone: $!";
$!=0; $?=0; if (!close FETCHERR) {
fail "reap fetch/clone: $!" if $!;
my $fetchfail =
!($? & 255) ? "$cmd died with error exit code ".($? >> 8) :
$? != 9 ? "$cmd died due to fatal signa, status $?" :
$timedout ? "$cmd timed out (${fetchtimeout}s)" :
"$cmd died due to unexpected SIGKILL";
if (length $fetcherr) {
$fetchfail .= "\n$fetcherr";
$fetchfail =~ s/\n$//;
$fetchfail =~ s{\n}{ // }g;
}
if ($fetch >= 2) {
gitfail $fetchfail;
} else {
servinfo "fetch/clone failed: $fetchfail";
}
}
if (!$exists) {
rename $tmpd, $gitd or fail "rename fresh $tmpd to $gitd: $!";
$exists = 1;
}
} else {
$fetchfail = 'not attempted';
}
if (!$exists) {
gitfail "no cached data, and not cloned: $fetchfail";
}
servinfo "sharing";
lockfile \*LOCK, $lock, LOCK_SH; # NB releases and relocks
if (stat $gitd) {
return 1;
}
$!==ENOENT or fail "stat $gitd: $!";
# Well, err, someone must have taken the lock in between
# and garbage collected it. How annoying.
return 0;
}
sub hkfail ($) { my ($msg) = @_; fail "housekeeping: $msg"; }
sub housekeeping () {
logm 'info', "housekeeping started";
foreach $lock (<[a-z]*\\.lock>) {
my $subdir = $lock; $subdir =~ s/\\.lock$//;
if (!lstat $lock) {
$! == ENOENT or hkfail "$lock: lstat: $!";
next;
}
if (-M _ <= $treeexpiredays) {
logm 'debug', "housekeeping: subdirs $subdir: touched recently";
next;
}
if (!lockfile \*LOCK, $lock, LOCK_EX|LOCK_NB) {
logm 'info', "housekeeping: subdirs $subdir: lock busy, skipping";
next;
}
logm 'info', "housekeeping: subdirs $subdir: cleaning";
eval {
foreach my $suffix (qw(tmp git)) {
my $dir = "${subdir}\\.$suffix";
my $tdir = "${subdir}\\.tmp";
if ($dir ne $tdir) {
if (!rename $dir,$tdir) {
next if $! == ENOENT;
die "$dir: cannot rename to $tdir: $!\n";
}
}
system qw(rm -rf --), $tdir;
if (stat $tdir) {
die "$dir: problem deleting file(s), rm exited $?\n";
} elsif ($! != ENOENT) {
die "$tdir: cannot stat after deletion: $!\n";
}
}
};
if (length $@) {
chomp $@;
logm 'warning', "housekeeping: $subdir: cleanup prevented: $@";
} else {
unlink $lock or hkfail "remove $lock: $!";
}
}
open HS, ">", "Housekeeping.stamp" or hkfail "touch Housekeeping.stamp: $!";
close HS or hkfail "close Housekeeping.stamp: $!";
logm 'info', "housekeeping finished";
}
sub housekeepingcheck ($$) {
my ($dofork, $force) = @_;
if (!$force) {
if (!lockfile \*HLOCK, "Housekeeping.lock", LOCK_EX|LOCK_NB) {
logm 'debug', "housekeeping lock taken, not running";
close HLOCK;
return 0;
}
}
if ($force) {
logm 'info', "housekeeping forced";
} elsif (!lstat "Housekeeping.stamp") {
$! == ENOENT or fail "lstat Housekeeping.stamp: $!";
logm 'info', "housekeeping not done yet, will run";
} elsif (-M _ <= $housekeepingeverydays) {
logm 'debug', "housekeeping done recently";
close HLOCK;
return 0;
}
if ($dofork) {
my $child = fork;
defined $child or fail "fork: $!";
if (!$child) {
open STDERR, "|logger -p daemon.warning -t '$us(housekeeping)'"
or die "fork: logger $!";
housekeeping();
exit 0;
}
} else {
housekeeping();
}
close HLOCK;
return 1;
}
sub runcommand () {
servinfo "serving";
chdir $gitd or fail "chdir $gitd: $!";
exec qw(git-upload-pack --strict --timeout=1000 .)
or fail "exec git-upload-pack: $!";
}
sub daemonservice () {
readcommand();
while (!clonefetch()) { }
housekeepingcheck(1,0);
runcommand();
}
if ($housekeepingonly) {
housekeepingcheck(0, $housekeepingonly>=2);
} else {
daemonservice();
}
|