Address review comments

diff --git a/contrib/docker/rootfs_prefix/rootfs_prefix.c b/contrib/docker/rootfs_prefix/rootfs_prefix.c
index 65be0720b2ba9ea789a666945849b8ce4892ed7a..2b831518dce43e09dc99e20b4283efeb6f3aee9e 100644 (file)
--- a/contrib/docker/rootfs_prefix/rootfs_prefix.c
+++ b/contrib/docker/rootfs_prefix/rootfs_prefix.c
@@ -11,20 +11,20 @@
 #define BUFSIZE 256
 
 const char *add_prefix(const char *orig, char *prefixed) {
-  if ((strncmp(orig, "/proc", 5) != 0) && (strncmp(orig, "/sys", 4) != 0))
+  if ((strncmp(orig, "/proc", strlen("/proc")) != 0) &&
+      (strncmp(orig, "/sys", strlen("/sys")) != 0))
     return orig;
 
   int status = snprintf(prefixed, BUFSIZE, "%s%s", PREFIX, orig);
-  if ((unsigned int)status >= BUFSIZE) {
+  if (status < 1) {
+    error(status, errno, "adding '%s' prefix to file path failed: '%s' -> '%s'",
+          PREFIX, orig, prefixed);
+    return orig;
+  } else if ((unsigned int)status >= BUFSIZE) {
     error(status, ENAMETOOLONG,
           "'%s' got truncated when adding '%s' prefix: '%s'", orig, PREFIX,
           prefixed);
     return orig;
-  } else if (status < 1) {
-    error(status, errno,
-          "adding '%s' prefix to file path failed: '%s' -> '%s'", PREFIX,
-          orig, prefixed);
-    return orig;
   } else {
     return (const char *)prefixed;
   }