From 7b30d5d15b6999b8b4fb3f221004c8a49c185c4e Mon Sep 17 00:00:00 2001
From: Andrew Gaul <andrew@gaul.org>
Date: Sat, 22 Apr 2017 16:15:02 -0700
Subject: [PATCH] Do not send canned ACL header when empty string

Some providers such as StorageGRID do not support canned ACLs.
Setting to empty allows callers to omit the header.  References #125.
---
 src/curl.cpp      | 12 +++++++++---
 src/s3fs_util.cpp |  5 +++--
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/curl.cpp b/src/curl.cpp
index d062af907e..3421f75062 100644
--- a/src/curl.cpp
+++ b/src/curl.cpp
@@ -2611,7 +2611,9 @@ int S3fsCurl::PutHeadRequest(const char* tpath, headers_t& meta, bool is_copy)
   }
 
   // "x-amz-acl", storage class, sse
-  requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-acl", S3fsCurl::default_acl.c_str());
+  if(!S3fsCurl::default_acl.empty()){
+    requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-acl", S3fsCurl::default_acl.c_str());
+  }
   if(REDUCED_REDUNDANCY == GetStorageClass()){
     requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-storage-class", "REDUCED_REDUNDANCY");
   } else if(STANDARD_IA == GetStorageClass()){
@@ -2731,7 +2733,9 @@ int S3fsCurl::PutRequest(const char* tpath, headers_t& meta, int fd)
     }
   }
   // "x-amz-acl", storage class, sse
-  requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-acl", S3fsCurl::default_acl.c_str());
+  if(!S3fsCurl::default_acl.empty()){
+    requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-acl", S3fsCurl::default_acl.c_str());
+  }
   if(REDUCED_REDUNDANCY == GetStorageClass()){
     requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-storage-class", "REDUCED_REDUNDANCY");
   } else if(STANDARD_IA == GetStorageClass()){
@@ -3045,7 +3049,9 @@ int S3fsCurl::PreMultipartPostRequest(const char* tpath, headers_t& meta, string
     }
   }
   // "x-amz-acl", storage class, sse
-  requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-acl", S3fsCurl::default_acl.c_str());
+  if(!S3fsCurl::default_acl.empty()){
+    requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-acl", S3fsCurl::default_acl.c_str());
+  }
   if(REDUCED_REDUNDANCY == GetStorageClass()){
     requestHeaders = curl_slist_sort_insert(requestHeaders, "x-amz-storage-class", "REDUCED_REDUNDANCY");
   } else if(STANDARD_IA == GetStorageClass()){
diff --git a/src/s3fs_util.cpp b/src/s3fs_util.cpp
index 0ce2b7ffaf..776250da81 100644
--- a/src/s3fs_util.cpp
+++ b/src/s3fs_util.cpp
@@ -950,8 +950,9 @@ void show_help (void)
     "        must specify this option after -o option for bucket name.\n"
     "\n"
     "   default_acl (default=\"private\")\n"
-    "      - the default canned acl to apply to all written s3 objects\n"
-    "        see http://aws.amazon.com/documentation/s3/ for the \n"
+    "      - the default canned acl to apply to all written s3 objects,\n"
+    "        e.g., private, public-read.  empty string means do not send\n"
+    "        header.  see http://aws.amazon.com/documentation/s3/ for the\n"
     "        full list of canned acls\n"
     "\n"
     "   retries (default=\"2\")\n"