systemd-run-shim-user.patch

# This patch modifys systemd-run-shim to use systemd --user for starting the
# unit. This works on my local machine but fails on the server, where the
# playground worker itself runs inside a systemd unit. I'm not sure if that has
# to do with it. In any case, that's why this patch is currently not applied.

diff --git a/play-haskell-worker/bwrap-files/systemd-run-shim.c b/play-haskell-worker/bwrap-files/systemd-run-shim.c
index 0915e8b..993fffb 100644
--- a/play-haskell-worker/bwrap-files/systemd-run-shim.c
+++ b/play-haskell-worker/bwrap-files/systemd-run-shim.c
@@ -48,13 +48,13 @@ int main(int argc, char **argv) {
   const uid_t parent_uid = getuid();
   const uid_t parent_gid = getgid();
 
-  if (parent_uid == 0 || parent_gid == 0) {
-    fprintf(stderr,
-        "%s must not be run as root, it must be marked setuid root "
-        "and run as a normal user.\n",
-        argv[0]);
-    return 1;
-  }
+  // if (parent_uid == 0 || parent_gid == 0) {
+  //   fprintf(stderr,
+  //       "%s must not be run as root, it must be marked setuid root "
+  //       "and run as a normal user.\n",
+  //       argv[0]);
+  //   return 1;
+  // }
 
   if (argc <= 1) {
     fprintf(stderr,
@@ -75,29 +75,30 @@ int main(int argc, char **argv) {
 
   // Note: the allocation size here must be increased if the number of
   // arguments to systemd-run increases.
-  const size_t num_pre_args = 17;
+  const size_t num_pre_args = 16;
   char ** const run_args = malloc((num_pre_args + num_given_args + 1) * sizeof(*run_args));
 
   run_args[0] = xstrdup("systemd-run");
   run_args[1] = xstrdup("--description=play-haskell-worker cpuquota");
   run_args[2] = xasprintf("--unit=%s", unit_name);
-  run_args[3] = xasprintf("--uid=%u", parent_uid);
-  run_args[4] = xasprintf("--gid=%u", parent_gid);
-  run_args[5] = xstrdup("--pipe");
-  run_args[6] = xstrdup("--wait");
-  run_args[7] = xstrdup("--collect");
-  run_args[8] = xstrdup("--same-dir");
-  run_args[9] = xstrdup("--service-type=exec");
-  run_args[10] = xasprintf("--setenv=PATH=%s", getenv("PATH"));
-  run_args[11] = xstrdup("--quiet");
-  run_args[12] = xstrdup("--property=CPUQuota=100%");
+  // run_args[3] = xasprintf("--uid=%u", parent_uid);
+  // run_args[4] = xasprintf("--gid=%u", parent_gid);
+  run_args[3] = xstrdup("--pipe");
+  run_args[4] = xstrdup("--wait");
+  run_args[5] = xstrdup("--collect");
+  run_args[6] = xstrdup("--same-dir");
+  run_args[7] = xstrdup("--service-type=exec");
+  run_args[8] = xasprintf("--setenv=PATH=%s", getenv("PATH"));
+  run_args[9] = xstrdup("--quiet");
+  run_args[10] = xstrdup("--property=CPUQuota=100%");
   // Limit memory to 600 MiB. Note that the compiled program gets a 500 MiB memory
   // limit via the GHC RTS, so this limit is 1. to constrain GHC itself (including
   // any TH code), and 2. as a second-layer defense.
-  run_args[13] = xstrdup("--property=MemoryMax=600M");
-  run_args[14] = xstrdup("--property=TasksMax=50");
-  run_args[15] = xstrdup("--property=LimitCORE=0");
-  run_args[16] = xstrdup("--");
+  run_args[11] = xstrdup("--property=MemoryMax=600M");
+  run_args[12] = xstrdup("--property=TasksMax=50");
+  run_args[13] = xstrdup("--property=LimitCORE=0");
+  run_args[14] = xstrdup("--user");
+  run_args[15] = xstrdup("--");
   // If more arguments are added above, please modify the run_args allocation above!
   for (int i = 0; i < num_given_args; i++) {
     run_args[num_pre_args + i] = xstrdup(given_args[i]);