feat(cert_pool): add AppendCertsFromFile func

src/crypto/x509/cert_pool.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"encoding/pem"
+	"os"
 	"sync"
 )
 
@@ -210,6 +211,19 @@ func (s *CertPool) addCertFunc(rawSum224 sum224, rawSubject string, getCert func
 	s.byName[rawSubject] = append(s.byName[rawSubject], len(s.lazyCerts)-1)
 }
 
+// AppendCertsFromFile attempts to parse a series of File certificates.
+// It appends any certificates found to s and reports whether any certificates
+// were successfully parsed.
+// If an error occurs while reading the file, an error will be returned.
+func (s *CertPool) AppendCertsFromFile(path string) (bool, error) {
+	file, err := os.ReadFile(path)
+	if err != nil {
+		return false, err
+	}
+
+	return s.AppendCertsFromPEM(file), nil
+}
+
 // AppendCertsFromPEM attempts to parse a series of PEM encoded certificates.
 // It appends any certificates found to s and reports whether any certificates
 // were successfully parsed.

src/crypto/x509/root_plan9.go

@@ -23,9 +23,8 @@ func loadSystemRoots() (*CertPool, error) {
 	roots := NewCertPool()
 	var bestErr error
 	for _, file := range certFiles {
-		data, err := os.ReadFile(file)
+		_, err := roots.AppendCertsFromFile(file)
 		if err == nil {
-			roots.AppendCertsFromPEM(data)
 			return roots, nil
 		}
 		if bestErr == nil || (os.IsNotExist(bestErr) && !os.IsNotExist(err)) {

src/crypto/x509/root_unix.go

@@ -39,9 +39,8 @@ func loadSystemRoots() (*CertPool, error) {
 
 	var firstErr error
 	for _, file := range files {
-		data, err := os.ReadFile(file)
+		_, err := roots.AppendCertsFromFile(file)
 		if err == nil {
-			roots.AppendCertsFromPEM(data)
 			break
 		}
 		if firstErr == nil && !os.IsNotExist(err) {
@@ -67,10 +66,7 @@ func loadSystemRoots() (*CertPool, error) {
 			continue
 		}
 		for _, fi := range fis {
-			data, err := os.ReadFile(directory + "/" + fi.Name())
-			if err == nil {
-				roots.AppendCertsFromPEM(data)
-			}
+			_, err := roots.AppendCertsFromFile(directory + "/" + fi.Name())
 		}
 	}