-#!/usr/bin/perl
+#!/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>/OPTIONS<real-git-url>
+# "git://<realhost>:<realport>/<real-git-url>[ <options>]"
# where <real-git-url> is http://<host>/... or git://<host>/...
-# and OPTIONS is zero or more of
+# 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=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 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 $log; # filehandle (ref), or "1" meaning syslog
+
+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 $sockaddr = shift;
return ("[$addr]:$port",$addr,$port);
}
-our ($client,$client_addr,$client_port) = ntoa getpeername STDIN;
-our ($server,$server_addr,$server_port) = ntoa getsockname STDIN;
+our ($client) = ntoa getpeername STDIN;
+our ($server) = ntoa getsockname STDIN;
sub ensurelog () {
return if $log;
$log = 1;
}
-sub log ($) {
+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,
+ $pri eq 'err' ? 'error' : $pri,
$mainmsg);
print $log $wholemsg;
} else {
- syslog $pri, $mainmsg;
+ 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) = @_;
- log 'error', $msg;
- exit 1;
+ logm 'err', $msg;
+ exit 0;
}
sub gitfail ($) {
my ($msg) = @_;
close LOCK;
alarm 60;
- log 'notice', $msg;
+ 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 1;
+ exit 0;
}
-our $cachedir = '/var/cache/git-cache-proxy';
+#---------- argument parsing ----------
for (;;) {
last unless @ARGV;
$_ = shift @ARGV;
for (;;) {
last unless m/^-./;
- if (s/^-L(.*)$//) {
+ 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 = $1;
- } elsif (s/^--(maxfetchtimeout|fetchtimeout)=(\d+)$//) {
- ${ $::{$1} } = $2;
+ } elsif (s/^--( max-fetch-timeout
+ | fetch-timeout
+ | tree-expire-days
+ | housekeeping-interval-days
+ )=(\d+)$//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";
-chdir $cachedir or fail "chdir $cachedir: $!";
-
-our ($service,$specpath,$spechost);
+#---------- utility functions ----------
-$SIG{ALRM} = sub { fail "timeout" };
-alarm 30;
+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
+ 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;
}
-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) = $line =~
- m|^(git-[a-z-]+) /*([!-~]+)\0host=([!-~]+)\0$|) {
- $line =~ s|[^ -~]+| |g;
- fail "Could not parse \"$line\""
+
+#---------- 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': $msg";
}
-alarm 0;
-
-$service eq 'git-upload-pack'
- or gitfail "unknown/unsupported service `$service'";
-
-my $fetch = 2; # 0:don't; 1:try; 2:force
-my $url = $specpath;
-
-while ($url =~ s#^(\[)([^][{}])+\]## ||
- $url =~ s#^(\{)([^][{}])+\}##) {
- $_ = $2;
- my $must = $1 eq '{';
- if (m/^fetch=try$/) {
- $fetch = 1;
- } elsif (m/^fetch=no$/) {
- $fetch = 0;
- } elsif (m/^fetch=must$/) {
- $fetch = 2; # the default
- } elsif (m/^timeout=(\d+)$/) {
- $fetchtimeout = $1 <= $maxfetchtimeout ? $1 : $maxfetchtimeout;
- } elsif ($must) {
- gitfail "unknown/unsupported option `$_'";
+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'"
}
-}
-$url =~ m{^(?:https?|git)://[-.0-9a-z]+/}
- or gitfail "unknown/unsupported url scheme or format `$url'";
+ 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 `$_'";
+ }
+ }
-our $subdir = $url;
-$subdir =~ s|\\|\\\\|g;
-$subdir =~ s|,|\\,|g;
-$subdir =~ s|/|,|g;
+ $url =~ m{^(?:https?|git)://[-.0-9a-z]+/}
+ or gitfail "unknown/unsupported url scheme or format `$url'";
-log 'info', "$specpath locking";
+ $subdir = $url;
+ $subdir =~ s|\\|\\\\|g;
+ $subdir =~ s|,|\\,|g;
+ $subdir =~ s|/|,|g;
-my $tmpd= "$subdir\\.tmp";
-my $gitd= "$subdir\\.git";
-my $lock = "$subdir\\.lock";
+ $tmpd= "$subdir\\.tmp";
+ $gitd= "$subdir\\.git";
+ $lock = "$subdir\\.lock";
-for (;;) {
- open LOCK, "+>", $lock or fail "open/create $lock: $!";
- flock LOCK, LOCK_EX or fail "lock exclusive $lock: $!";
+ servinfo "locking";
+}
+
+sub clonefetch () {
+ lockfile \*LOCK, $lock, LOCK_EX;
- my $exists = stat $gitd;
- $exists or $!==ENOENT or FAIL "stat $gitd: $!";
+ my $exists = lstat $gitd;
+ $exists or $!==ENOENT or fail "lstat $gitd: $!";
our $fetchfail = '';
if (!$exists) {
system qw(rm -rf --), $tmpd;
- @cmd = qw(git clone -q --mirror), $url;
- log 'info', "$specpath cloning";
+ @cmd = (qw(git clone -q --mirror), $url, $tmpd);
+ servinfo "cloning";
} else {
- @cmd = qw(git remote update --prune), $url;
- log 'info', "$specpath fetching";
+ @cmd = (qw(git remote update --prune));
+ servinfo "fetching";
}
+ my $cmd = "@cmd[0..1]";
my $child = open FETCHERR, "-|";
defined $child or fail "fork: $!";
exec @cmd or fail "exec $cmd[0]: $!";
}
+ my $fetcherr = '';
my $timedout = 0;
{
- local $SIG{ALARM} = sub { $timedout=1; kill 9, -$child; };
+ local $SIG{ALRM} = sub {
+ servinfo "fetch/clone timeout";
+ $timedout=1; kill 9, -$child;
+ };
alarm($fetchtimeout);
- my $fetcherr = '';
$!=0; { local $/=undef; $fetcherr = <FETCHERR>; }
!FETCHERR->error or fail "read pipe from fetch/clone: $!";
alarm(10);
$!=0; $?=0; if (!close FETCHERR) {
fail "reap fetch/clone: $!" if $!;
my $fetchfail =
- !($? & 255) ? "$cmd[0] died with error exit code ".($? >> 8) :
- $? != 9 ? "$cmd[0] died due to fatal signa, status $?" :
- $timedout ? "$cmd[0] timed out (${fetchtimeout}s)" :
- "$cmd[0] died due to unexpected SIGKILL";
+ !($? & 255) ? "$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 $fetchfail;
} else {
- log 'info', "$specpatch fetch failed: $fetchfail";
+ servinfo "fetch/clone failed: $fetchfail";
}
}
gitfail "no cached data, and not cloned: $fetchfail";
}
- flock LOCK, LOCK_UN for fail "unlock $lock: $!";
- flock LOCK, LOCK_SH for fail "lock shared $lock: $!";
- # actually, just relocking as shared would have the same semantics
- # but it's best to be explicit
+ servinfo "sharing";
+ lockfile \*LOCK, $lock, LOCK_SH; # NB releases and relocks
- if (chdir $gitd) {
- last;
+ if (stat $gitd) {
+ return 1;
}
- $!==ENOENT or fail "chdir $gitd: $!";
+ $!==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";
+ }
+ }
+ my $errs;
+ remove_tree($tdir, { safe=>1, error=>\$errs });
+ if (!stat $tdir) {
+ foreach my $err (@$errs) {
+ my ($file, $message) = %$err;
+ logm 'info', "problem deleting: $file: $message";
+ }
+ die "$dir: problem deleting file(s)\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";
}
-exec qw(git-upload-pack --strict --timeout=1000 .)
- or fail "exec git-upload-pack: $!";
+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 hkfail "fork: $!";
+ if (!$child) {
+ 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();
+}
~ian / chiark-utils.git / blobdiff