commit 853378b46df13e33c7d08109f219cb38f4532b71
Author: nyyu <mail@nyyu.dev>
Date:   Tue Apr 30 09:12:09 2024 +0200

    feat: init

diff --git a/.woodpecker.yml b/.woodpecker.yml
new file mode 100644
index 0000000..53fa11e
--- /dev/null
+++ b/.woodpecker.yml
@@ -0,0 +1,15 @@
+steps:
+  docker:
+    image: docker-public.nyyu.dev/nyyu/plugin-kaniko
+    pull: true
+    settings:
+      username:
+        from_secret: registry_username
+      password:
+        from_secret: registry_password
+      repo: ${CI_REPO_OWNER}/numcpu_override
+      registry: ${DOCKER_REGISTRY}
+      tags: alpine
+    when:
+      branch: ${CI_REPO_DEFAULT_BRANCH}
+      event: [push, manual, tag]
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..fffa592
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,9 @@
+FROM alpine:3.18
+COPY . .
+RUN apk add --no-cache gcc musl-dev && \
+  gcc -shared -fPIC -Wall -Wextra -Werror numcpu_override.c -o numcpu_override.so -ldl
+
+FROM alpine:3.18
+COPY /copy.sh /
+COPY --from=0 numcpu_override.so /
+ENTRYPOINT ["/copy.sh"]
diff --git a/copy.sh b/copy.sh
new file mode 100755
index 0000000..9d93a58
--- /dev/null
+++ b/copy.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "copy '$(ls *.so)' to /_libs/"
+cp -f *.so /_libs/
diff --git a/numcpu_override.c b/numcpu_override.c
new file mode 100644
index 0000000..da23d20
--- /dev/null
+++ b/numcpu_override.c
@@ -0,0 +1,32 @@
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+
+typedef long (*orig_sysconf_f_type)(int name);
+
+long sysconf(int name) {
+  orig_sysconf_f_type orig;
+  orig = (orig_sysconf_f_type)dlsym(RTLD_NEXT, "sysconf");
+
+  if (name != _SC_NPROCESSORS_CONF && name != _SC_NPROCESSORS_ONLN) {
+    return orig(name);
+  }
+
+  printf("Overriding call sysconf %d\n", name);
+
+  long numcpus = 0;
+  char *env = getenv("NUMCPUS");
+  printf("Env NUMCPUS %s\n", env);
+  if (env != NULL && strlen(env) > 0) {
+    numcpus = strtol(env, NULL, 10);
+  }
+  if (numcpus == 0) {
+    numcpus = orig(name);
+  }
+  printf("Return %ld\n", numcpus);
+  fflush(stdout);
+  return numcpus;
+}