diff --git a/init/builtins.cpp b/init/builtins.cpp
index 08a715c..2260358 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -155,7 +155,7 @@
 }
 
 static int do_domainname(const std::vector<std::string>& args) {
-    return write_file("/proc/sys/kernel/domainname", args[1].c_str()) ? 0 : 1;
+    return write_file("/proc/sys/kernel/domainname", args[1]) ? 0 : 1;
 }
 
 static int do_enable(const std::vector<std::string>& args) {
@@ -179,7 +179,7 @@
 }
 
 static int do_hostname(const std::vector<std::string>& args) {
-    return write_file("/proc/sys/kernel/hostname", args[1].c_str()) ? 0 : 1;
+    return write_file("/proc/sys/kernel/hostname", args[1]) ? 0 : 1;
 }
 
 static int do_ifup(const std::vector<std::string>& args) {
@@ -648,9 +648,7 @@
 }
 
 static int do_write(const std::vector<std::string>& args) {
-    const char* path = args[1].c_str();
-    const char* value = args[2].c_str();
-    return write_file(path, value) ? 0 : 1;
+    return write_file(args[1], args[2]) ? 0 : 1;
 }
 
 static int do_copy(const std::vector<std::string>& args) {
diff --git a/init/init_parser.cpp b/init/init_parser.cpp
index 326ebf2..a192862 100644
--- a/init/init_parser.cpp
+++ b/init/init_parser.cpp
@@ -96,7 +96,7 @@
     LOG(INFO) << "Parsing file " << path << "...";
     Timer t;
     std::string data;
-    if (!read_file(path.c_str(), &data)) {
+    if (!read_file(path, &data)) {
         return false;
     }
 
diff --git a/init/util.cpp b/init/util.cpp
index 73d97ed..c06d51b 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -161,10 +161,11 @@
     return -1;
 }
 
-bool read_file(const char* path, std::string* content) {
+bool read_file(const std::string& path, std::string* content) {
     content->clear();
 
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
+    android::base::unique_fd fd(
+        TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
     if (fd == -1) {
         return false;
     }
@@ -184,9 +185,9 @@
     return android::base::ReadFdToString(fd, content);
 }
 
-bool write_file(const char* path, const char* content) {
+bool write_file(const std::string& path, const std::string& content) {
     android::base::unique_fd fd(
-        TEMP_FAILURE_RETRY(open(path, O_WRONLY | O_CREAT | O_NOFOLLOW | O_CLOEXEC, 0600)));
+        TEMP_FAILURE_RETRY(open(path.c_str(), O_WRONLY | O_CREAT | O_NOFOLLOW | O_CLOEXEC, 0600)));
     if (fd == -1) {
         PLOG(ERROR) << "write_file: Unable to open '" << path << "'";
         return false;
diff --git a/init/util.h b/init/util.h
index 81c64d7..90ec6bb 100644
--- a/init/util.h
+++ b/init/util.h
@@ -32,8 +32,8 @@
 int create_socket(const char *name, int type, mode_t perm,
                   uid_t uid, gid_t gid, const char *socketcon);
 
-bool read_file(const char* path, std::string* content);
-bool write_file(const char* path, const char* content);
+bool read_file(const std::string& path, std::string* content);
+bool write_file(const std::string& path, const std::string& content);
 
 // A std::chrono clock based on CLOCK_BOOTTIME.
 class boot_clock {
diff --git a/init/util_test.cpp b/init/util_test.cpp
index 24c75c4..6134998 100644
--- a/init/util_test.cpp
+++ b/init/util_test.cpp
@@ -18,6 +18,7 @@
 
 #include <errno.h>
 
+#include <android-base/test_utils.h>
 #include <gtest/gtest.h>
 
 TEST(util, read_file_ENOENT) {
@@ -37,6 +38,23 @@
   EXPECT_STREQ("Linux", s.c_str());
 }
 
+TEST(util, write_file_binary) {
+    std::string contents("abcd");
+    contents.push_back('\0');
+    contents.push_back('\0');
+    contents.append("dcba");
+    ASSERT_EQ(10u, contents.size());
+
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    EXPECT_TRUE(write_file(tf.path, contents)) << strerror(errno);
+
+    std::string read_back_contents;
+    EXPECT_TRUE(read_file(tf.path, &read_back_contents)) << strerror(errno);
+    EXPECT_EQ(contents, read_back_contents);
+    EXPECT_EQ(10u, read_back_contents.size());
+}
+
 TEST(util, decode_uid) {
   EXPECT_EQ(0U, decode_uid("root"));
   EXPECT_EQ(UINT_MAX, decode_uid("toot"));