cmd: continue lint fixes.

cmd/readchain/main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"flag"
+	"fmt"
+	"os"
+)
+
+func main() {
+	flag.Parse()
+
+	for _, fileName := range flag.Args() {
+		data, err := os.ReadFile(fileName)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "[!] %s: %v\n", fileName, err)
+			continue
+		}
+
+		fmt.Fprintf(os.Stdout, "[+] %s:\n", fileName)
+		rest := data
+		for {
+			var p *pem.Block
+			p, rest = pem.Decode(rest)
+			if p == nil {
+				break
+			}
+
+			cert, err := x509.ParseCertificate(p.Bytes)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "[!] %s: %v\n", fileName, err)
+				break
+			}
+
+			fmt.Fprintf(os.Stdout, "\t%+v\n", cert.Subject.CommonName)
+		}
+	}
+}