git-cache-proxy: wip based on userv-utils git-daemon and git-service

diff --git a/scripts/git-cache-proxy b/scripts/git-cache-proxy
new file mode 100644 (file)
index 0000000..d8ef34d
--- /dev/null
+++ b/scripts/git-cache-proxy
@@ -0,0 +1,230 @@
+#!/usr/bin/perl
+#
+# git caching proxy
+#
+# usage: run it on some port, and then clone or fetch
+#  git://<realhost>:<realport>/<real-git-url>
+# where <real-git-url> is http://<host>/... or git://<host>/...
+
+use strict;
+use warnings;
+
+use POSIX;
+use Socket;
+use Sys::Syslog;
+
+our $us = 'git-cache-proxy';
+our $log; # filehandle (ref), or "1" meaning syslog
+our $fetchtimeout = 1800;
+our $maxfetchtimeout = 3600;
+
+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,$client_addr,$client_port) = ntoa getpeername STDIN;
+our ($server,$server_addr,$server_port) = ntoa getsockname STDIN;
+
+sub ensurelog () {
+    return if $log;
+    openlog $us, qw(pid), 'daemon';
+    $log = 1;
+}
+
+sub log ($) {
+    my ($pri, $msg) = @_;
+    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,
+                              $mainmsg);
+       print $log $wholemsg;
+    } else {
+       syslog $pri, $mainmsg;
+    }
+}
+
+sub fail ($) {
+    my ($msg) = @_;
+    log 'error', $msg;
+    exit 1;
+}
+
+sub gitfail ($) {
+    my ($msg) = @_;
+    log 'warning', $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;
+}
+
+our $cachedir = '/var/cache/git-cache-proxy';
+
+for (;;) {
+    last unless @ARGV;
+    last unless $ARGV[0] =~ m/^-/;
+    $_ = shift @ARGV;
+    for (;;) {
+       last unless m/^-./;
+       if (s/^-L(.*)$//) {
+           my $logfile = $_;
+           open STDERR, ">>", $logfile or fail "open $logfile: $!";
+           $log = \*STDERR;
+       } elsif (s/^-d(.*)$//) {
+           $cachedir = $1;
+       } elsif (s/^--(maxfetchtimeout|fetchtimeout)=(\d+)$//) {
+           ${ $::{$1} } = $2;
+       } else {
+           fail "bad usage: unknown option `$_'";
+       }
+    }
+}
+
+!@ARGV or fail "bad usage: no non-option arguments permitted";
+
+chdir $cachedir or fail "chdir $cachedir: $!";
+
+our ($service,$specpath,$spechost);
+
+$SIG{ALRM} = sub { fail "timeout" };
+alarm 30;
+
+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;
+}
+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\""
+}
+
+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 = $1 eq '{';
+    if (m/^relaxed$/) {
+       $fetch = 1;
+    } elsif (m/^nofetch$/) {
+       $fetch = 0;
+    } elsif (m/^timeout=(\d+)$/) {
+       $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'";
+
+our $subdir = $url;
+$subdir =~ s|\\|\\\\|g;
+$subdir =~ s|,|\\,|g;
+$subdir =~ s|/|,|g;
+
+log 'info', "$specpath locking";
+
+my $tmpd= "$subdir\\.tmp";
+my $gitd= "$subdir\\.git";
+my $lock = "$subdir\\.lock";
+
+open LOCK, "+>", $lock or fail "open/create $lock: $!";
+flock LOCK, LOCK_EX or fail "lock $lock: $!";
+
+$exists = stat $gitd;
+$exists or $!==ENOENT or FAIL "stat $gitd: $!";
+
+if ($fetch) {
+
+    our @cmd;
+
+    if (!$exists) {
+       system qw(rm -rf --), $tmpd;
+       @cmd = qw(git clone -q --mirror), $url;
+       log 'info', "$specpath cloning";
+    } else {
+       @cmd = qw(git remote update --prune), $url;
+       log 'info', "$specpath fetching";
+    }
+
+    my $child = open P, "-|";
+    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]: $!";
+    }
+
+    local $SIG{ALARM} = sub {
+       kill 9, -$child;
+       
+       } or log 'crit', 
+    };
+
+    alarm($fetchtimeout);
+    
+
+printf STDERR "%s [$$] %s %s\n",
+    strftime("%Y-%m-%d %H:%M:%S %Z", localtime), $server, $client;
+
+
+
+
+
+$service eq '
+
+@@READ_URLMAP@@
+
+fail "No global mapping for $uri" unless defined $serve_user;
+
+my ($hn,$ha,$at,$naddrs,@addrs) = gethostbyname $spechost;
+fail "hostname/address mismatch ($spechost $server_addr)" unless grep {
+    $server_addr eq inet_ntoa $_
+    } @addrs;
+
+our @opts;
+
+push @opts, "-D$_=${$::{$_}}"
+    for qw(service specpath spechost
+          client client_addr client_port
+          server server_addr server_port);
+
+fail "no user $serve_user" unless getpwnam($serve_user);
+
+syslog 'notice', "$client $service $uri $serve_user";
+
+my @cmd = ('userv', '-t300', @opts, $serve_user, $service);
+no warnings; # suppress errors to stderr
+exec @cmd or fail "exec userv: $!";
+
+# end