1 files changed, 55 insertions, 5 deletions
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 02e314f64..d8569d7b9 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -702,11 +702,61 @@ static int do_write(const std::vector<std::string>& args) {
 }
 
 static int do_copy(const std::vector<std::string>& args) {
-    std::string data;
-    if (read_file(args[1].c_str(), &data)) {
-        return write_file(args[2].c_str(), data.data()) ? 0 : 1;
-    }
-    return 1;
+    char *buffer = NULL;
+    int rc = 0;
+    int fd1 = -1, fd2 = -1;
+    struct stat info;
+    int brtw, brtr;
+    char *p;
+
+    if (stat(args[1].c_str(), &info) < 0)
+        return -1;
+
+    if ((fd1 = open(args[1].c_str(), O_RDONLY|O_CLOEXEC)) < 0)
+        goto out_err;
+
+    if ((fd2 = open(args[2].c_str(), O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0660)) < 0)
+        goto out_err;
+
+    if (!(buffer = (char*) malloc(info.st_size)))
+        goto out_err;
+
+    p = buffer;
+    brtr = info.st_size;
+    while(brtr) {
+        rc = read(fd1, p, brtr);
+        if (rc < 0)
+            goto out_err;
+        if (rc == 0)
+            break;
+        p += rc;
+        brtr -= rc;
+    }
+
+    p = buffer;
+    brtw = info.st_size;
+    while(brtw) {
+        rc = write(fd2, p, brtw);
+        if (rc < 0)
+            goto out_err;
+        if (rc == 0)
+            break;
+        p += rc;
+        brtw -= rc;
+    }
+
+    rc = 0;
+    goto out;
+out_err:
+    rc = -1;
+out:
+    if (buffer)
+        free(buffer);
+    if (fd1 >= 0)
+        close(fd1);
+    if (fd2 >= 0)
+        close(fd2);
+    return rc;
 }
 
 static int do_chown(const std::vector<std::string>& args) {