peip

commit 4a29096fc0418e7cb4b1d5412e850ccb76cbd074
Author: aperturefever <glyr@pm.me>
Date:   Sat, 26 Sep 2026 18:28:32 +0300

Initial commit

Diffstat:
A
.gitignore
 | 
6
++++++
A
Makefile
 | 
33
+++++++++++++++++++++++++++++++++
A
README.md
 | 
0

A
go.mod
 | 
5
+++++
A
go.sum
 | 
2
++
A
main.go
 | 
42
++++++++++++++++++++++++++++++++++++++++++
A
pledge_openbsd.go
 | 
15
+++++++++++++++
A
pledge_other.go
 | 
5
+++++

8 files changed, 108 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,6 @@
+# built binaries
+peip
+*.test
+
+# editors
+*.swp
diff --git a/Makefile b/Makefile
@@ -0,0 +1,33 @@
+# Makefile for peip
+.PHONY: build openbsd clean install help
+
+BIN_NAME=peip
+BIN_PATH=/var/www/cgi-bin/$(BIN_NAME)
+OWNER=root:www
+GO=go
+GOOS_OPENBSD=openbsd
+GOARCH_OPENBSD=amd64
+LDFLAGS_OPENBSD=-linkmode external -extldflags -static
+
+all: build
+## build: build project for the current host (non-openbsd)
+build:
+	$(GO) build -o $(BIN_NAME) .
+## openbsd: cross-build a static binary for openbsd/amd64
+openbsd:
+	GOOS=$(GOOS_OPENBSD) GOARCH=$(GOARCH_OPENBSD) $(GO) build -ldflags "$(LDFLAGS_OPENBSD)" -o $(BIN_NAME) .
+## clean: cleanup current and destination project binaries
+clean:
+	rm -f $(BIN_PATH)
+	rm -f $(BIN_NAME)
+
+## install: build for openbsd and place in destination directories
+install: openbsd
+	mkdir -p $(dir $(BIN_PATH))
+	cp $(BIN_NAME) $(BIN_PATH)
+	chmod 755 $(BIN_PATH)
+	-chown $(OWNER) $(BIN_PATH)
+## help: this help
+help:
+	@echo "Available targets:"
+	@grep -E '^## ' Makefile | sed 's/^## /:: /'
diff --git a/README.md b/README.md
diff --git a/go.mod b/go.mod
@@ -0,0 +1,5 @@
+module peip
+
+go 1.26.5
+
+require golang.org/x/sys v0.47.0
diff --git a/go.sum b/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
+golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
diff --git a/main.go b/main.go
@@ -0,0 +1,42 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/cgi"
+	"strings"
+)
+
+func handleRequest(w http.ResponseWriter, r *http.Request) {
+	envVal := r.Header.Get("X-Forwarded-For")
+	if envVal == "" {
+		http.Error(w, "Missing Header", http.StatusBadRequest)
+		return
+	}
+
+	remoteIP := envVal
+	if comma := strings.Index(envVal, ","); comma != -1 {
+		remoteIP = envVal[:comma]
+	}
+	remoteIP = strings.TrimSpace(remoteIP)
+
+	if parsedIP := net.ParseIP(remoteIP); parsedIP == nil {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusBadRequest)
+		fmt.Fprintf(w, "Invalid IP: %s", remoteIP)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
+	fmt.Fprint(w, remoteIP)
+}
+
+func main() {
+	pledge()
+
+	if err := cgi.Serve(http.HandlerFunc(handleRequest)); err != nil {
+		panic(err)
+	}
+}
diff --git a/pledge_openbsd.go b/pledge_openbsd.go
@@ -0,0 +1,15 @@
+//go:build openbsd
+
+package main
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+func pledge() {
+	if err := unix.Pledge("stdio", ""); err != nil {
+		panic(fmt.Sprintf("pledge failed: %v", err))
+	}
+}
diff --git a/pledge_other.go b/pledge_other.go
@@ -0,0 +1,5 @@
+//go:build !openbsd
+
+package main
+
+func pledge() {}