From 78f97b28b4693750d0c108764171cc1e19ab7d17 Mon Sep 17 00:00:00 2001
From: Vrganj <luka.barbic0@gmail.com>
Date: Mon, 25 Jan 2021 18:24:34 +0100
Subject: [PATCH] Possibly fix stdin newlines

---
 lxc/execute       | 50 +++++++++++++++++------------------------------
 shared/execute.js | 14 +++++++------
 2 files changed, 26 insertions(+), 38 deletions(-)

diff --git a/lxc/execute b/lxc/execute
index 51f2eca..3dff13f 100755
--- a/lxc/execute
+++ b/lxc/execute
@@ -9,60 +9,46 @@ if [ -z "$1" ] || [ -z "$2" ]; then
     exit
 fi
 
-lang=$1
-epoch=$(date +%s%N)
-basepath="/var/lib/lxc/piston/rootfs"
-filepath="/tmp/$epoch/code.code"
-argpath="/tmp/$epoch/args.args"
-stdinpath="/tmp/$epoch/stdin.stdin"
-arg=$(basename $argpath)
+language=$1
+id=$2
 
-# write arg file
-mkdir -p $basepath/tmp/$epoch
-chmod 777 $basepath/tmp/$epoch
-cat $2 > $basepath$filepath
-echo $3 > $basepath$stdinpath
-echo -n "${@:4}" > $basepath$argpath
+basepath="/var/lib/lxc/piston/rootfs"
 
 # process incrementor
 exec 200>$dir/lockfile
-flock -x 200
-oldinc=$(cat $dir/i | awk '{$1=$1};1')
-newinc=$(expr $oldinc + 1)
+flock 200
 
-if (( newinc >= 151 )); then
-    newinc=1
-    echo 1 > $dir/i
-else
-    echo $newinc > $dir/i
-fi
+runner=$(cat $dir/i)
+let 'runner = runner % 150 + 1'
+
+echo $runner > $dir/i
 exec 200>&-
 
 # prevent users from spying on each other
 lxc-attach --clear-env -n piston -- \
     /bin/bash -l -c "
-        chown runner$newinc: -R /tmp/$epoch
-        chmod 700 /tmp/$epoch
+        chown runner$runner -R /tmp/$id
+        chmod 700 /tmp/$id
     " > /dev/null 2>&1
 
 # runner
 timeout -s KILL 20 \
     lxc-attach --clear-env -n piston -- \
-        /bin/bash -l -c "runuser runner$newinc /exec/$lang $newinc $epoch"
+        /bin/bash -l -c "runuser runner$runner /exec/$language runner$runner $id"
 
 # process janitor
 lxc-attach --clear-env -n piston -- \
     /bin/bash -l -c "
         for i in {1..100}
         do
-            pkill -u runner$newinc --signal SIGKILL
+            pkill -u runner$runner --signal SIGKILL
         done
 
-        find /tmp -user runner$newinc -delete
-        find /var/tmp -user runner$newinc -delete
-        find /var/lock -user runner$newinc -delete
-        find /dev/shm -user runner$newinc -delete
-        find /run/lock -user runner$newinc -delete
+        find /tmp -user runner$runner -delete
+        find /var/tmp -user runner$runner -delete
+        find /var/lock -user runner$runner -delete
+        find /dev/shm -user runner$runner -delete
+        find /run/lock -user runner$runner -delete
     " > /dev/null 2>&1 &
 
-rm -rf $basepath/tmp/$epoch
+rm -rf $basepath/tmp/$id
diff --git a/shared/execute.js b/shared/execute.js
index 526efdd..cd90820 100644
--- a/shared/execute.js
+++ b/shared/execute.js
@@ -1,20 +1,22 @@
-const { writeFileSync, unlinkSync } = require('fs');
+const { writeFileSync, unlinkSync, mkdirSync } = require('fs');
 const { spawn } = require('child_process');
 
 const OUTPUT_LIMIT = 65535;
+const LXC_ROOT = '/var/lib/lxc/piston/rootfs';
 
 function execute(language, source, stdin = '', args = []) {
     return new Promise(resolve => {
-        const stamp = new Date().getTime();
+        const id = new Date().getTime() + '_' + Math.floor(Math.random() * 10000000);
         const sourceFile = `/tmp/${stamp}.code`;
 
-        writeFileSync(sourceFile, source);
+        mkdirSync(`${LXC_ROOT}/tmp/${id}`);
+        writeFileSync(`${LXC_ROOT}/tmp/${id}/code.code`, source);
+        writeFileSync(`${LXC_ROOT}/tmp/${id}/stdin.stdin`, stdin);
+        writeFileSync(`${LXC_ROOT}/tmp/${id}/args.args`, args.join('\n'));
 
         const process = spawn(__dirname + '/../lxc/execute', [
             language.name,
-            sourceFile,
-            stdin,
-            args.join('\n'),
+            id,
         ]);
 
         let stdout = '';