Sign request immediately before sending

Previously s3fs could create a long list of pre-signed requests which
could take longer than the default S3 clock skew limit of 15 minutes.
This also changes SHA-256 computation from single- to multi-threaded
since this is now computed in the worker threads.  Regression from
88cd8feb05.  Fixes #1019.

src/curl.cpp

@@ -1582,7 +1582,6 @@ bool S3fsCurl::UploadMultipartPostSetCurlOpts(S3fsCurl* s3fscurl)
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_INFILESIZE_LARGE, static_cast<curl_off_t>(s3fscurl->partdata.size)); // Content-Length
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_READFUNCTION, UploadReadCallback);
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_READDATA, (void*)s3fscurl);
-  curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HTTPHEADER, s3fscurl->requestHeaders);
   S3fsCurl::AddUserAgent(s3fscurl->hCurl);                            // put User-Agent
 
   return true;
@@ -1604,7 +1603,6 @@ bool S3fsCurl::CopyMultipartPostSetCurlOpts(S3fsCurl* s3fscurl)
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HEADERDATA, (void*)(&s3fscurl->headdata));
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HEADERFUNCTION, WriteMemoryCallback);
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_INFILESIZE, 0);               // Content-Length
-  curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HTTPHEADER, s3fscurl->requestHeaders);
   S3fsCurl::AddUserAgent(s3fscurl->hCurl);                                // put User-Agent
 
   return true;
@@ -1620,7 +1618,6 @@ bool S3fsCurl::PreGetObjectRequestSetCurlOpts(S3fsCurl* s3fscurl)
   }
 
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_URL, s3fscurl->url.c_str());
-  curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HTTPHEADER, s3fscurl->requestHeaders);
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_WRITEFUNCTION, DownloadWriteCallback);
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_WRITEDATA, (void*)s3fscurl);
   S3fsCurl::AddUserAgent(s3fscurl->hCurl);        // put User-Agent
@@ -1640,7 +1637,6 @@ bool S3fsCurl::PreHeadRequestSetCurlOpts(S3fsCurl* s3fscurl)
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_URL, s3fscurl->url.c_str());
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_NOBODY, true);   // HEAD
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_FILETIME, true); // Last-Modified
-  curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HTTPHEADER, s3fscurl->requestHeaders);
 
   // responseHeaders
   curl_easy_setopt(s3fscurl->hCurl, CURLOPT_HEADERDATA, (void*)&(s3fscurl->responseHeaders));
@@ -1947,6 +1943,13 @@ bool S3fsCurl::CreateCurlHandle(bool only_pool, bool remake)
     }
   }
 
+  ResetHandle();
+
+  return true;
+}
+
+bool S3fsCurl::DestroyCurlHandle(bool restore_pool, bool clear_internal_data)
+{
   // [NOTE]
   // If type is REQTYPE_IAMCRED or REQTYPE_IAMROLE, do not clear type.
   // Because that type only uses HTTP protocol, then the special
@@ -1956,13 +1959,6 @@ bool S3fsCurl::CreateCurlHandle(bool only_pool, bool remake)
     type = REQTYPE_UNSET;
   }
 
-  ResetHandle();
-
-  return true;
-}
-
-bool S3fsCurl::DestroyCurlHandle(bool restore_pool, bool clear_internal_data)
-{
   if(clear_internal_data){
     ClearInternalData();
   }
@@ -2085,14 +2081,12 @@ bool S3fsCurl::RemakeHandle()
     case REQTYPE_DELETE:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_CUSTOMREQUEST, "DELETE");
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_HEAD:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_NOBODY, true);
       curl_easy_setopt(hCurl, CURLOPT_FILETIME, true);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       // responseHeaders
       curl_easy_setopt(hCurl, CURLOPT_HEADERDATA, (void*)&responseHeaders);
       curl_easy_setopt(hCurl, CURLOPT_HEADERFUNCTION, HeaderCallback);
@@ -2104,7 +2098,6 @@ bool S3fsCurl::RemakeHandle()
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
       curl_easy_setopt(hCurl, CURLOPT_INFILESIZE, 0);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_PUT:
@@ -2112,7 +2105,6 @@ bool S3fsCurl::RemakeHandle()
       curl_easy_setopt(hCurl, CURLOPT_UPLOAD, true);
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       if(b_infile){
         curl_easy_setopt(hCurl, CURLOPT_INFILESIZE_LARGE, static_cast<curl_off_t>(st.st_size));
         curl_easy_setopt(hCurl, CURLOPT_INFILE, b_infile);
@@ -2123,7 +2115,6 @@ bool S3fsCurl::RemakeHandle()
 
     case REQTYPE_GET:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, S3fsCurl::DownloadWriteCallback);
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)this);
       break;
@@ -2132,14 +2123,12 @@ bool S3fsCurl::RemakeHandle()
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_LISTBUCKET:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_PREMULTIPOST:
@@ -2148,12 +2137,10 @@ bool S3fsCurl::RemakeHandle()
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
       curl_easy_setopt(hCurl, CURLOPT_POSTFIELDSIZE, 0);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_COMPLETEMULTIPOST:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       curl_easy_setopt(hCurl, CURLOPT_POST, true);
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
@@ -2172,7 +2159,6 @@ bool S3fsCurl::RemakeHandle()
       curl_easy_setopt(hCurl, CURLOPT_INFILESIZE_LARGE, static_cast<curl_off_t>(partdata.size));
       curl_easy_setopt(hCurl, CURLOPT_READFUNCTION, S3fsCurl::UploadReadCallback);
       curl_easy_setopt(hCurl, CURLOPT_READDATA, (void*)this);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_COPYMULTIPOST:
@@ -2183,21 +2169,18 @@ bool S3fsCurl::RemakeHandle()
       curl_easy_setopt(hCurl, CURLOPT_HEADERDATA, (void*)&headdata);
       curl_easy_setopt(hCurl, CURLOPT_HEADERFUNCTION, WriteMemoryCallback);
       curl_easy_setopt(hCurl, CURLOPT_INFILESIZE, 0);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_MULTILIST:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_IAMCRED:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
       curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       if(S3fsCurl::is_ibm_iam_auth){
         curl_easy_setopt(hCurl, CURLOPT_POST, true);
         curl_easy_setopt(hCurl, CURLOPT_POSTFIELDSIZE, static_cast<curl_off_t>(postdata_remaining));
@@ -2209,7 +2192,6 @@ bool S3fsCurl::RemakeHandle()
     case REQTYPE_ABORTMULTIUPLOAD:
       curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(hCurl, CURLOPT_CUSTOMREQUEST, "DELETE");
-      curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
       break;
 
     case REQTYPE_IAMROLE:
@@ -2242,6 +2224,9 @@ int S3fsCurl::RequestPerform()
   long responseCode;
   int result        = S3FSCURL_PERFORM_RESULT_NOTSET;
 
+  insertAuthHeaders();
+  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
+
   // 1 attempt + retries...
   for(int retrycnt = 0; S3FSCURL_PERFORM_RESULT_NOTSET == result && retrycnt < S3fsCurl::retries; ++retrycnt){
     // Reset response code
@@ -2688,11 +2673,9 @@ int S3fsCurl::DeleteRequest(const char* tpath)
 
   op = "DELETE";
   type = REQTYPE_DELETE;
-  insertAuthHeaders();
 
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_CUSTOMREQUEST, "DELETE");
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);        // put User-Agent
 
   return RequestPerform();
@@ -2758,7 +2741,6 @@ int S3fsCurl::GetIAMCredentials()
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);        // put User-Agent
 
   int result = RequestPerform();
@@ -2882,7 +2864,6 @@ bool S3fsCurl::PreHeadRequest(const char* tpath, const char* bpath, const char*
 
   op = "HEAD";
   type = REQTYPE_HEAD;
-  insertAuthHeaders();
 
   // set lazy function
   fpLazySetup = PreHeadRequestSetCurlOpts;
@@ -3019,7 +3000,6 @@ int S3fsCurl::PutHeadRequest(const char* tpath, headers_t& meta, bool is_copy)
 
   op = "PUT";
   type = REQTYPE_PUTHEAD;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
@@ -3027,7 +3007,6 @@ int S3fsCurl::PutHeadRequest(const char* tpath, headers_t& meta, bool is_copy)
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
   curl_easy_setopt(hCurl, CURLOPT_INFILESIZE, 0);               // Content-Length
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);                                // put User-Agent
 
   S3FS_PRN_INFO3("copying... [path=%s]", tpath);
@@ -3148,14 +3127,12 @@ int S3fsCurl::PutRequest(const char* tpath, headers_t& meta, int fd)
 
   op = "PUT";
   type = REQTYPE_PUT;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_UPLOAD, true);                // HTTP PUT
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   if(file){
     curl_easy_setopt(hCurl, CURLOPT_INFILESIZE_LARGE, static_cast<curl_off_t>(st.st_size)); // Content-Length
     curl_easy_setopt(hCurl, CURLOPT_INFILE, file);
@@ -3206,7 +3183,6 @@ int S3fsCurl::PreGetObjectRequest(const char* tpath, int fd, off_t start, ssize_
 
   op = "GET";
   type = REQTYPE_GET;
-  insertAuthHeaders();
 
   // set lazy function
   fpLazySetup = PreGetObjectRequestSetCurlOpts;
@@ -3276,13 +3252,11 @@ int S3fsCurl::CheckBucket()
 
   op = "GET";
   type = REQTYPE_CHKBUCKET;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);        // put User-Agent
 
   int result = RequestPerform();
@@ -3319,13 +3293,11 @@ int S3fsCurl::ListBucketRequest(const char* tpath, const char* query)
 
   op = "GET";
   type = REQTYPE_LISTBUCKET;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);        // put User-Agent
 
   return RequestPerform();
@@ -3419,7 +3391,6 @@ int S3fsCurl::PreMultipartPostRequest(const char* tpath, headers_t& meta, string
 
   op = "POST";
   type = REQTYPE_PREMULTIPOST;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
@@ -3427,7 +3398,6 @@ int S3fsCurl::PreMultipartPostRequest(const char* tpath, headers_t& meta, string
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
   curl_easy_setopt(hCurl, CURLOPT_POSTFIELDSIZE, 0);
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);                            // put User-Agent
 
   // request
@@ -3496,11 +3466,9 @@ int S3fsCurl::CompleteMultipartPostRequest(const char* tpath, string& upload_id,
 
   op = "POST";
   type = REQTYPE_COMPLETEMULTIPOST;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   curl_easy_setopt(hCurl, CURLOPT_POST, true);              // POST
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
@@ -3540,13 +3508,11 @@ int S3fsCurl::MultipartListRequest(string& body)
 
   op = "GET";
   type = REQTYPE_MULTILIST;
-  insertAuthHeaders();
 
   // setopt
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_WRITEDATA, (void*)&bodydata);
   curl_easy_setopt(hCurl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);        // put User-Agent
 
   int result;
@@ -3583,11 +3549,9 @@ int S3fsCurl::AbortMultipartUpload(const char* tpath, string& upload_id)
 
   op = "DELETE";
   type = REQTYPE_ABORTMULTIUPLOAD;
-  insertAuthHeaders();
 
   curl_easy_setopt(hCurl, CURLOPT_URL, url.c_str());
   curl_easy_setopt(hCurl, CURLOPT_CUSTOMREQUEST, "DELETE");
-  curl_easy_setopt(hCurl, CURLOPT_HTTPHEADER, requestHeaders);
   S3fsCurl::AddUserAgent(hCurl);        // put User-Agent
 
   return RequestPerform();
@@ -3658,7 +3622,6 @@ int S3fsCurl::UploadMultipartPostSetup(const char* tpath, int part_num, const st
 
   op = "PUT";
   type = REQTYPE_UPLOADMULTIPOST;
-  insertAuthHeaders();
 
   // set lazy function
   fpLazySetup = UploadMultipartPostSetCurlOpts;
@@ -3733,7 +3696,6 @@ int S3fsCurl::CopyMultipartPostSetup(const char* from, const char* to, int part_
 
   op = "PUT";
   type = REQTYPE_COPYMULTIPOST;
-  insertAuthHeaders();
 
   // set lazy function
   fpLazySetup = CopyMultipartPostSetCurlOpts;

src/gnutls_auth.cpp

@@ -196,17 +196,12 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
   ssize_t        bytes;
   unsigned char* result;
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   md5_init(&ctx_md5);
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -221,11 +216,6 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
   result = new unsigned char[get_md5_digest_length()];
   md5_digest(&ctx_md5, get_md5_digest_length(), result);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 
@@ -247,11 +237,6 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
     size = static_cast<ssize_t>(st.st_size);
   }
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   if(GPG_ERR_NO_ERROR != (err = gcry_md_open(&ctx_md5, GCRY_MD_MD5, 0))){
     S3FS_PRN_ERR("MD5 context creation failure: %s/%s", gcry_strsource(err), gcry_strerror(err));
@@ -260,7 +245,7 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -277,11 +262,6 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
   memcpy(result, gcry_md_read(ctx_md5, 0), get_md5_digest_length());
   gcry_md_close(ctx_md5);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 
@@ -316,17 +296,12 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
   ssize_t           bytes;
   unsigned char*    result;
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   sha256_init(&ctx_sha256);
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -341,11 +316,6 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
   result = new unsigned char[get_sha256_digest_length()];
   sha256_digest(&ctx_sha256, get_sha256_digest_length(), result);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 
@@ -386,11 +356,6 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
     size = static_cast<ssize_t>(st.st_size);
   }
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   if(GPG_ERR_NO_ERROR != (err = gcry_md_open(&ctx_sha256, GCRY_MD_SHA256, 0))){
     S3FS_PRN_ERR("SHA256 context creation failure: %s/%s", gcry_strsource(err), gcry_strerror(err));
@@ -399,7 +364,7 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -416,11 +381,6 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
   memcpy(result, gcry_md_read(ctx_sha256, 0), get_sha256_digest_length());
   gcry_md_close(ctx_sha256);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 

src/nss_auth.cpp

@@ -167,17 +167,12 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
     size = static_cast<ssize_t>(st.st_size);
   }
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   md5ctx = PK11_CreateDigestContext(SEC_OID_MD5);
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -194,11 +189,6 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
   PK11_DigestFinal(md5ctx, result, &md5outlen, get_md5_digest_length());
   PK11_DestroyContext(md5ctx, PR_TRUE);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 
@@ -243,17 +233,12 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
     size = static_cast<ssize_t>(st.st_size);
   }
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   sha256ctx = PK11_CreateDigestContext(SEC_OID_SHA256);
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -270,11 +255,6 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
   PK11_DigestFinal(sha256ctx, result, &sha256outlen, get_sha256_digest_length());
   PK11_DestroyContext(sha256ctx, PR_TRUE);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 

src/openssl_auth.cpp

@@ -239,17 +239,12 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
     size = static_cast<ssize_t>(st.st_size);
   }
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   memset(buf, 0, 512);
   MD5_Init(&md5ctx);
 
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -265,11 +260,6 @@ unsigned char* s3fs_md5hexsum(int fd, off_t start, ssize_t size)
   result = new unsigned char[get_md5_digest_length()];
   MD5_Final(result, &md5ctx);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
-
   return result;
 }
 
@@ -312,18 +302,13 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
     size = static_cast<ssize_t>(st.st_size);
   }
 
-  // seek to top of file.
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    return NULL;
-  }
-
   sha256ctx = EVP_MD_CTX_create();
   EVP_DigestInit_ex(sha256ctx, md, NULL);
 
   memset(buf, 0, 512);
   for(ssize_t total = 0; total < size; total += bytes){
     bytes = 512 < (size - total) ? 512 : (size - total);
-    bytes = read(fd, buf, bytes);
+    bytes = pread(fd, buf, bytes, start + total);
     if(0 == bytes){
       // end of file
       break;
@@ -340,10 +325,6 @@ unsigned char* s3fs_sha256hexsum(int fd, off_t start, ssize_t size)
   EVP_DigestFinal_ex(sha256ctx, result, NULL);
   EVP_MD_CTX_destroy(sha256ctx);
 
-  if(-1 == lseek(fd, start, SEEK_SET)){
-    delete[] result;
-    return NULL;
-  }
   return result;
 }