diff --git a/apps/wolfsshd/configuration.c b/apps/wolfsshd/configuration.c
index 71d2d5de6..fd2852818 100644
--- a/apps/wolfsshd/configuration.c
+++ b/apps/wolfsshd/configuration.c
@@ -658,7 +658,7 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value)
                     char** fileNames = NULL;
 
                     /* Count up the number of files */
-                    while ((dir = WREADDIR(&d)) != NULL) {
+                    while ((dir = WREADDIR(NULL, &d)) != NULL) {
                         /* Skip sub-directories */
                     #if defined(__QNX__) || defined(__QNXNTO__)
                         struct stat s;
@@ -672,7 +672,7 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value)
                             fileCount++;
                         }
                     }
-                    WREWINDDIR(&d);
+                    WREWINDDIR(NULL, &d);
 
                     if (fileCount > 0) {
                         fileNames = (char**)WMALLOC(fileCount * sizeof(char*),
@@ -684,7 +684,7 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value)
 
                     if (ret == WS_SUCCESS) {
                         i = 0;
-                        while (i < fileCount && (dir = WREADDIR(&d)) != NULL) {
+                        while (i < fileCount && (dir = WREADDIR(NULL, &d)) != NULL) {
                             /* Skip sub-directories */
                         #if defined(__QNX__) || defined(__QNXNTO__)
                             struct stat s;
@@ -752,7 +752,7 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value)
                             WFREE(fileNames, conf->heap, DYNTYPE_PATH);
                         }
                     }
-                    WCLOSEDIR(&d);
+                    WCLOSEDIR(NULL, &d);
                 }
                 else {
                     /* Bad directory */
diff --git a/apps/wolfsshd/test/test_configuration.c b/apps/wolfsshd/test/test_configuration.c
index 1528731ec..4c1000e23 100644
--- a/apps/wolfsshd/test/test_configuration.c
+++ b/apps/wolfsshd/test/test_configuration.c
@@ -33,7 +33,7 @@ static void CleanupWildcardTest(void)
     char filepath[MAX_PATH*2]; /* d_name is max_path long */
 
     if (!WOPENDIR(NULL, NULL, &dir, "./sshd_config.d/")) {
-        while ((d = WREADDIR(&dir)) != NULL) {
+        while ((d = WREADDIR(NULL, &dir)) != NULL) {
         #if defined(__QNX__) || defined(__QNXNTO__)
             struct stat s;
 
@@ -48,7 +48,7 @@ static void CleanupWildcardTest(void)
                 WREMOVE(0, filepath);
             }
         }
-        WCLOSEDIR(&dir);
+        WCLOSEDIR(NULL, &dir);
         WRMDIR(0, "./sshd_config.d/");
     }
 }
@@ -75,15 +75,15 @@ static int SetupWildcardTest(void)
                         "./sshd_config.d/");
             }
 
-            WFOPEN(&f, filepath, "w");
+            WFOPEN(NULL, &f, filepath, "w");
             if (f) {
                 word32 sz, wr;
                 char contents[20];
                 WSNPRINTF(contents, sizeof contents, "LoginGraceTime %02u",
                         fileIds[i]);
                 sz = (word32)WSTRLEN(contents);
-                wr = (word32)WFWRITE(contents, sizeof(char), sz, f);
-                WFCLOSE(f);
+                wr = (word32)WFWRITE(NULL, contents, sizeof(char), sz, f);
+                WFCLOSE(NULL, f);
                 if (sz != wr) {
                     Log("Couldn't write the contents of file %s\n", filepath);
                     ret = WS_FATAL_ERROR;
diff --git a/apps/wolfsshd/wolfsshd.c b/apps/wolfsshd/wolfsshd.c
index 4991b62dc..6ff992734 100644
--- a/apps/wolfsshd/wolfsshd.c
+++ b/apps/wolfsshd/wolfsshd.c
@@ -207,22 +207,22 @@ static byte* getBufferFromFile(const char* fileName, word32* bufSz, void* heap)
 
     if (fileName == NULL) return NULL;
 
-    if (WFOPEN(&file, fileName, "rb") != 0)
+    if (WFOPEN(NULL, &file, fileName, "rb") != 0)
         return NULL;
-    WFSEEK(file, 0, XSEEK_END);
-    fileSz = (word32)WFTELL(file);
-    WREWIND(file);
+    WFSEEK(NULL, file, 0, XSEEK_END);
+    fileSz = (word32)WFTELL(NULL, file);
+    WREWIND(NULL, file);
 
     buf = (byte*)WMALLOC(fileSz + 1, heap, DYNTYPE_SSHD);
     if (buf != NULL) {
-        readSz = (word32)WFREAD(buf, 1, fileSz, file);
+        readSz = (word32)WFREAD(NULL, buf, 1, fileSz, file);
         if (readSz < fileSz) {
-            WFCLOSE(file);
+            WFCLOSE(NULL, file);
             WFREE(buf, heap, DYNTYPE_SSHD);
             return NULL;
         }
         *bufSz = readSz;
-        WFCLOSE(file);
+        WFCLOSE(NULL, file);
     }
 
     (void)heap;
@@ -573,7 +573,7 @@ static int SFTP_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
                     "[SSHD] Error setting SFTP default home path");
                 ret = WS_FATAL_ERROR;
             }
-            WCLOSEDIR(&dir);
+            WCLOSEDIR(NULL, &dir);
         }
     }
 
diff --git a/examples/client/common.c b/examples/client/common.c
index d66603ca3..6e48a4b67 100644
--- a/examples/client/common.c
+++ b/examples/client/common.c
@@ -248,29 +248,29 @@ static int load_der_file(const char* filename, byte** out, word32* outSz)
     if (filename == NULL || out == NULL || outSz == NULL)
         return -1;
 
-    ret = WFOPEN(&file, filename, "rb");
+    ret = WFOPEN(NULL, &file, filename, "rb");
     if (ret != 0 || file == WBADFILE)
         return -1;
 
-    if (WFSEEK(file, 0, WSEEK_END) != 0) {
-        WFCLOSE(file);
+    if (WFSEEK(NULL, file, 0, WSEEK_END) != 0) {
+        WFCLOSE(NULL, file);
         return -1;
     }
-    inSz = (word32)WFTELL(file);
-    WREWIND(file);
+    inSz = (word32)WFTELL(NULL, file);
+    WREWIND(NULL, file);
 
     if (inSz == 0) {
-        WFCLOSE(file);
+        WFCLOSE(NULL, file);
         return -1;
     }
 
     in = (byte*)WMALLOC(inSz, NULL, 0);
     if (in == NULL) {
-        WFCLOSE(file);
+        WFCLOSE(NULL, file);
         return -1;
     }
 
-    ret = (int)WFREAD(in, 1, inSz, file);
+    ret = (int)WFREAD(NULL, in, 1, inSz, file);
     if (ret <= 0 || (word32)ret != inSz) {
         ret = -1;
         WFREE(in, NULL, 0);
@@ -283,7 +283,7 @@ static int load_der_file(const char* filename, byte** out, word32* outSz)
     *out = in;
     *outSz = inSz;
 
-    WFCLOSE(file);
+    WFCLOSE(NULL, file);
 
     return ret;
 }
diff --git a/examples/echoserver/echoserver.c b/examples/echoserver/echoserver.c
index ebff84394..ab1338e0d 100644
--- a/examples/echoserver/echoserver.c
+++ b/examples/echoserver/echoserver.c
@@ -1411,7 +1411,7 @@ static int load_file(const char* fileName, byte* buf, word32* bufSz)
 
     if (fileName == NULL) return 0;
 
-    if (WFOPEN(&file, fileName, "rb") != 0)
+    if (WFOPEN(NULL, &file, fileName, "rb") != 0)
         return 0;
     fseek(file, 0, XSEEK_END);
     fileSz = (word32)ftell(file);
@@ -2511,10 +2511,10 @@ THREAD_RETURN WOLFSSH_THREAD echoserver_test(void* args)
     #ifndef NO_FILESYSTEM
         WFILE* f = NULL;
         int    ret;
-        ret = WFOPEN(&f, readyFile, "w");
+        ret = WFOPEN(NULL, &f, readyFile, "w");
         if (f != NULL && ret == 0) {
             fprintf(f, "%d\n", (int)port);
-            WFCLOSE(f);
+            WFCLOSE(NULL, f);
         }
     #endif
     }
diff --git a/examples/server/server.c b/examples/server/server.c
index abdcb891f..1136d0135 100644
--- a/examples/server/server.c
+++ b/examples/server/server.c
@@ -282,7 +282,7 @@ static int load_file(const char* fileName, byte* buf, word32 bufSz)
 
     if (fileName == NULL) return 0;
 
-    if (WFOPEN(&file, fileName, "rb") != 0)
+    if (WFOPEN(NULL, &file, fileName, "rb") != 0)
         return 0;
     fseek(file, 0, SEEK_END);
     fileSz = (word32)ftell(file);
diff --git a/src/port.c b/src/port.c
index f8d6c0462..543c6dbb0 100644
--- a/src/port.c
+++ b/src/port.c
@@ -66,13 +66,13 @@ int wfopen(WFILE** f, const char* filename, const char* mode)
     }
 
     if (filename != NULL && f != NULL) {
-        if ((**f = WOPEN(filename, m, 0)) < 0) {
+        if ((**f = WOPEN(ssh->fs, filename, m, 0)) < 0) {
             return **f;
         }
 
         /* fopen defaults to normal */
         if (NU_Set_Attributes(filename, 0) != NU_SUCCESS) {
-            WCLOSE(**f);
+            WCLOSE(ssh->fs, **f);
             return 1;
         }
         return 0;
diff --git a/src/ssh.c b/src/ssh.c
index 2db5e340c..cc7ce7c90 100644
--- a/src/ssh.c
+++ b/src/ssh.c
@@ -1534,7 +1534,7 @@ int wolfSSH_ReadKey_buffer(const byte* in, word32 inSz, int format,
 }
 
 
-#ifndef NO_FILESYSTEM
+#if !defined(NO_FILESYSTEM) && !defined(WOLFSSH_USER_FILESYSTEM)
 
 /* Reads a key from the file name into a buffer. If the key starts with the
    string "ssh-rsa" or "ecdsa-sha2-nistp256", it is considered an SSH format
@@ -1557,27 +1557,27 @@ int wolfSSH_ReadKey_file(const char* name,
             isPrivate == NULL)
         return WS_BAD_ARGUMENT;
 
-    ret = WFOPEN(&file, name, "rb");
+    ret = WFOPEN(NULL, &file, name, "rb");
     if (ret != 0 || file == WBADFILE) return WS_BAD_FILE_E;
-    if (WFSEEK(file, 0, WSEEK_END) != 0) {
-        WFCLOSE(file);
+    if (WFSEEK(NULL, file, 0, WSEEK_END) != 0) {
+        WFCLOSE(NULL, file);
         return WS_BAD_FILE_E;
     }
-    inSz = (word32)WFTELL(file);
-    WREWIND(file);
+    inSz = (word32)WFTELL(NULL, file);
+    WREWIND(NULL, file);
 
     if (inSz > WOLFSSH_MAX_FILE_SIZE || inSz == 0) {
-        WFCLOSE(file);
+        WFCLOSE(NULL, file);
         return WS_BAD_FILE_E;
     }
 
     in = (byte*)WMALLOC(inSz + 1, heap, DYNTYPE_FILE);
     if (in == NULL) {
-        WFCLOSE(file);
+        WFCLOSE(NULL, file);
         return WS_MEMORY_E;
     }
 
-    ret = (int)WFREAD(in, 1, inSz, file);
+    ret = (int)WFREAD(NULL, in, 1, inSz, file);
     if (ret <= 0 || (word32)ret != inSz) {
         ret = WS_BAD_FILE_E;
     }
@@ -1599,7 +1599,7 @@ int wolfSSH_ReadKey_file(const char* name,
                 out, outSz, outType, outTypeSz, heap);
     }
 
-    WFCLOSE(file);
+    WFCLOSE(ssh->fs, file);
     WFREE(in, heap, DYNTYPE_FILE);
 
     return ret;
diff --git a/src/wolfscp.c b/src/wolfscp.c
index f3db331ef..55c42d042 100644
--- a/src/wolfscp.c
+++ b/src/wolfscp.c
@@ -53,8 +53,8 @@
 
 #ifndef NO_FILESYSTEM
 static int ScpFileIsDir(ScpSendCtx* ctx);
-static int ScpPushDir(ScpSendCtx* ctx, const char* path, void* heap);
-static int ScpPopDir(ScpSendCtx* ctx, void* heap);
+static int ScpPushDir(void *fs, ScpSendCtx* ctx, const char* path, void* heap);
+static int ScpPopDir(void *fs, ScpSendCtx* ctx, void* heap);
 #endif
 
 const char scpError[] = "scp error: %s, %d";
@@ -1165,11 +1165,12 @@ static int ParseBasePathHelper(WOLFSSH* ssh, int cmdSz)
         ScpSendCtx ctx;
 
         WMEMSET(&ctx, 0, sizeof(ScpSendCtx));
-        if (ScpPushDir(&ctx, ssh->scpBasePath, ssh->ctx->heap) != WS_SUCCESS) {
+
+        if (ScpPushDir(ssh->fs, &ctx, ssh->scpBasePath, ssh->ctx->heap) != WS_SUCCESS) {
             WLOG(WS_LOG_DEBUG, "scp : issue opening base dir");
         }
         else {
-            ret = ScpPopDir(&ctx, ssh->ctx->heap);
+            ret = ScpPopDir(ssh->fs, &ctx, ssh->ctx->heap);
             if (ret == WS_SCP_DIR_STACK_EMPTY_E) {
                 ret = WS_SUCCESS; /* is ok to empty the directory stack here */
             }
@@ -1910,7 +1911,7 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
                 }
             }
     #else
-            if (WCHDIR(basePath) != 0) {
+            if (WCHDIR(ssh->fs, basePath) != 0) {
                 WLOG(WS_LOG_ERROR,
                     "scp: invalid destination directory, abort");
                 wolfSSH_SetScpErrorMsg(ssh, "invalid destination directory");
@@ -1928,9 +1929,9 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
             WSTRNCAT(abslut, "/", WOLFSSH_MAX_FILENAME);
             WSTRNCAT(abslut, fileName, WOLFSSH_MAX_FILENAME);
             wolfSSH_CleanPath(ssh, abslut);
-            if (WFOPEN(&fp, abslut, "wb") != 0) {
+            if (WFOPEN(ssh->fs, &fp, abslut, "wb") != 0) {
         #else
-            if (WFOPEN(&fp, fileName, "wb") != 0) {
+            if (WFOPEN(ssh->fs, &fp, fileName, "wb") != 0) {
         #endif
                 WLOG(WS_LOG_ERROR,
                     "scp: unable to open file for writing, abort");
@@ -1954,11 +1955,11 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
                 break;
             }
             /* read file, or file part */
-            bytes = (word32)WFWRITE(buf, 1, bufSz, fp);
+            bytes = (word32)WFWRITE(ssh->fs, buf, 1, bufSz, fp);
             if (bytes != bufSz) {
                 WLOG(WS_LOG_ERROR, scpError, "scp receive callback unable "
                      "to write requested size to file", bytes);
-                WFCLOSE(fp);
+                WFCLOSE(ssh->fs, fp);
                 ret = WS_SCP_ABORT;
             } else {
 #ifdef WOLFSCP_FLUSH
@@ -1984,7 +1985,7 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
                 (void)fsync(fileno(fp));
                 flush_bytes = 0;
 #endif
-                WFCLOSE(fp);
+                WFCLOSE(ssh->fs, fp);
             }
 
             /* set timestamp info */
@@ -2041,7 +2042,7 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
                 WSTRNCAT((char*)basePath, fileName, WOLFSSH_MAX_FILENAME);
                 wolfSSH_CleanPath(ssh, (char*)basePath);
             #else
-                if (WCHDIR(fileName) != 0) {
+                if (WCHDIR(ssh->fs, fileName) != 0) {
                     WLOG(WS_LOG_ERROR,
                             "scp: unable to cd into direcotry, abort");
                     wolfSSH_SetScpErrorMsg(ssh, "unable to cd into directory");
@@ -2058,7 +2059,7 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
                 WSTRNCAT((char*)basePath, "/..", WOLFSSH_MAX_FILENAME - 1);
                 wolfSSH_CleanPath(ssh, (char*)basePath);
         #else
-            if (WCHDIR("..") != 0) {
+            if (WCHDIR(ssh->fs, "..") != 0) {
                 WLOG(WS_LOG_ERROR,
                             "scp: unable to cd out of direcotry, abort");
                 wolfSSH_SetScpErrorMsg(ssh, "unable to cd out of directory");
@@ -2079,23 +2080,27 @@ int wsScpRecvCallback(WOLFSSH* ssh, int state, const char* basePath,
     return ret;
 }
 
-static int GetFileSize(WFILE* fp, word32* fileSz)
+static int GetFileSize(void *fs, WFILE* fp, word32* fileSz)
 {
+    WOLFSSH_UNUSED(fs);
+
     if (fp == NULL || fileSz == NULL)
         return WS_BAD_ARGUMENT;
 
     /* get file size */
-    WFSEEK(fp, 0, WSEEK_END);
-    *fileSz = (word32)WFTELL(fp);
-    WREWIND(fp);
+    WFSEEK(fs, fp, 0, WSEEK_END);
+    *fileSz = (word32)WFTELL(fs, fp);
+    WREWIND(fs, fp);
 
     return WS_SUCCESS;
 }
 
-static int GetFileStats(ScpSendCtx* ctx, const char* fileName,
+static int GetFileStats(void *fs, ScpSendCtx* ctx, const char* fileName,
                         word64* mTime, word64* aTime, int* fileMode)
 {
     int ret = WS_SUCCESS;
+    
+    WOLFSSH_UNUSED(fs);
 
     if (ctx == NULL || fileName == NULL || mTime == NULL ||
         aTime == NULL || fileMode == NULL) {
@@ -2103,7 +2108,7 @@ static int GetFileStats(ScpSendCtx* ctx, const char* fileName,
     }
 
     /* get file stats for times and mode */
-    if (WSTAT(fileName, &ctx->s) < 0) {
+    if (WSTAT(fs, fileName, &ctx->s) < 0) {
         ret = WS_BAD_FILE_E;
         #ifdef WOLFSSL_NUCLEUS
         if (WSTRLEN(fileName) < 4 && WSTRLEN(fileName) > 2 &&
@@ -2138,8 +2143,10 @@ static int GetFileStats(ScpSendCtx* ctx, const char* fileName,
 
 /* Create new ScpDir struct for pushing on directory stack.
  * Return valid pointer on success, NULL on failure */
-static ScpDir* ScpNewDir(const char* path, void* heap)
+static ScpDir* ScpNewDir(void *fs, const char* path, void* heap)
 {
+    WOLFSSH_UNUSED(fs);
+
     ScpDir* entry = NULL;
 
     if (path == NULL) {
@@ -2155,7 +2162,7 @@ static ScpDir* ScpNewDir(const char* path, void* heap)
     }
 
     entry->next = NULL;
-    if (WOPENDIR(NULL, heap, &entry->dir, path) != 0
+    if (WOPENDIR(fs, heap, &entry->dir, path) != 0
         #ifndef WOLFSSL_NUCLEUS
             || entry->dir == NULL
         #endif
@@ -2170,14 +2177,14 @@ static ScpDir* ScpNewDir(const char* path, void* heap)
 }
 
 /* Create and push new ScpDir on stack, append directory to ctx->dirName */
-int ScpPushDir(ScpSendCtx* ctx, const char* path, void* heap)
+int ScpPushDir(void *fs, ScpSendCtx* ctx, const char* path, void* heap)
 {
     ScpDir* entry;
 
     if (ctx == NULL || path == NULL)
         return WS_BAD_ARGUMENT;
 
-    entry = ScpNewDir(path, heap);
+    entry = ScpNewDir(fs, path, heap);
     if (entry == NULL) {
         return WS_FATAL_ERROR;
     }
@@ -2198,8 +2205,10 @@ int ScpPushDir(ScpSendCtx* ctx, const char* path, void* heap)
 }
 
 /* Remove top ScpDir from directory stack, remove dir from ctx->dirName */
-int ScpPopDir(ScpSendCtx* ctx, void* heap)
+int ScpPopDir(void *fs, ScpSendCtx* ctx, void* heap)
 {
+    WOLFSSH_UNUSED(fs);
+
     ScpDir* entry = NULL;
     int idx = 0, separator = 0;
 
@@ -2209,7 +2218,7 @@ int ScpPopDir(ScpSendCtx* ctx, void* heap)
     }
 
     if (entry != NULL) {
-        WCLOSEDIR(&entry->dir);
+        WCLOSEDIR(fs, &entry->dir);
         WFREE(entry, heap, DYNTYPE_SCPDIR);
     }
 
@@ -2235,8 +2244,10 @@ int ScpPopDir(ScpSendCtx* ctx, void* heap)
 /* Get next entry in directory, either file or directory, skips self (.)
  * and parent (..) directories, stores in ctx->entry.
  * Return WS_SUCCESS on success or negative upon error */
-static int FindNextDirEntry(ScpSendCtx* ctx)
+static int FindNextDirEntry(void *fs, ScpSendCtx* ctx)
 {
+    WOLFSSH_UNUSED(fs);
+
     if (ctx == NULL)
         return WS_BAD_ARGUMENT;
 
@@ -2259,7 +2270,7 @@ static int FindNextDirEntry(ScpSendCtx* ctx)
     if (ctx->nextError == 1) {
         WDIR* dr;
         do {
-            dr = WREADDIR(&ctx->currentDir->dir);
+            dr = WREADDIR(fs, &ctx->currentDir->dir);
         } while (dr != NULL &&
              (WSTRNCMP(ctx->currentDir->dir.lfname, ".",  1) == 0 ||
               WSTRNCMP(ctx->currentDir->dir.lfname ,"..", 2) == 0));
@@ -2270,7 +2281,7 @@ static int FindNextDirEntry(ScpSendCtx* ctx)
     ctx->nextError = 1;
 #else
     do {
-        ctx->entry = WREADDIR(&ctx->currentDir->dir);
+        ctx->entry = WREADDIR(fs, &ctx->currentDir->dir);
     } while ((ctx->entry != NULL) &&
              (WSTRNCMP(ctx->entry->d_name, ".",  1) == 0 ||
               WSTRNCMP(ctx->entry->d_name ,"..", 2) == 0));
@@ -2361,7 +2372,7 @@ static int ScpProcessEntry(WOLFSSH* ssh, char* fileName, word64* mTime,
                      DEFAULT_SCP_FILE_NAME_SZ);
         #endif
             if (ret == WS_SUCCESS) {
-                ret = GetFileStats(sendCtx, filePath, mTime, aTime, fileMode);
+                ret = GetFileStats(ssh->fs, sendCtx, filePath, mTime, aTime, fileMode);
             }
         }
     }
@@ -2370,7 +2381,7 @@ static int ScpProcessEntry(WOLFSSH* ssh, char* fileName, word64* mTime,
 
         if (ScpFileIsDir(sendCtx)) {
 
-            ret = ScpPushDir(sendCtx, filePath, ssh->ctx->heap);
+            ret = ScpPushDir(ssh->fs, sendCtx, filePath, ssh->ctx->heap);
             if (ret == WS_SUCCESS) {
                 ret = WS_SCP_ENTER_DIR;
             } else {
@@ -2379,7 +2390,7 @@ static int ScpProcessEntry(WOLFSSH* ssh, char* fileName, word64* mTime,
             }
 
         } else if (ScpFileIsFile(sendCtx)) {
-            if (WFOPEN(&(sendCtx->fp), filePath, "rb") != 0) {
+            if (WFOPEN(ssh->fs, &(sendCtx->fp), filePath, "rb") != 0) {
                 WLOG(WS_LOG_ERROR, "scp: Error with oepning file, abort");
                 wolfSSH_SetScpErrorMsg(ssh, "unable to open file "
                                        "for reading");
@@ -2387,16 +2398,16 @@ static int ScpProcessEntry(WOLFSSH* ssh, char* fileName, word64* mTime,
             }
 
             if (ret == WS_SUCCESS) {
-                ret = GetFileSize(sendCtx->fp, totalFileSz);
+                ret = GetFileSize(ssh->fs, sendCtx->fp, totalFileSz);
 
                 if (ret == WS_SUCCESS)
-                    ret = (word32)WFREAD(buf, 1, bufSz, sendCtx->fp);
+                    ret = (word32)WFREAD(ssh->fs, buf, 1, bufSz, sendCtx->fp);
             }
 
             /* keep fp open if no errors and transfer will continue */
             if ((sendCtx->fp != NULL) &&
                 ((ret < 0) || (*totalFileSz == (word32)ret))) {
-                WFCLOSE(sendCtx->fp);
+                WFCLOSE(ssh->fs, sendCtx->fp);
             }
         }
 
@@ -2519,7 +2530,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
             break;
 
         case WOLFSSH_SCP_SINGLE_FILE_REQUEST:
-            if ((sendCtx == NULL) || WFOPEN(&(sendCtx->fp), peerRequest,
+            if ((sendCtx == NULL) || WFOPEN(ssh->fs, &(sendCtx->fp), peerRequest,
                                             "rb") != 0) {
 
                 WLOG(WS_LOG_ERROR, "scp: unable to open file, abort");
@@ -2538,10 +2549,10 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
             }
 
             if (ret == WS_SUCCESS)
-                ret = GetFileSize(sendCtx->fp, totalFileSz);
+                ret = GetFileSize(ssh->fs, sendCtx->fp, totalFileSz);
 
             if (ret == WS_SUCCESS)
-                ret = GetFileStats(sendCtx, peerRequest, mTime, aTime, fileMode);
+                ret = GetFileStats(ssh->fs, sendCtx, peerRequest, mTime, aTime, fileMode);
 
             if (ret == WS_SUCCESS)
                 ret = ExtractFileName(peerRequest, fileName, fileNameSz);
@@ -2549,7 +2560,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
             if (ret == WS_SUCCESS && sendCtx != NULL && sendCtx->fp != NULL) {
                 /* If it is an empty file, do not read. */
                 if (*totalFileSz != 0) {
-                    ret = (word32)WFREAD(buf, 1, bufSz, sendCtx->fp);
+                    ret = (word32)WFREAD(ssh->fs, buf, 1, bufSz, sendCtx->fp);
                     if (ret == 0) { /* handle unexpected case */
                         ret = WS_EOF;
                     }
@@ -2562,7 +2573,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
             /* keep fp open if no errors and transfer will continue */
             if ((sendCtx != NULL) && (sendCtx->fp != NULL) &&
                 ((ret < 0) || (*totalFileSz == (word32)ret))) {
-                WFCLOSE(sendCtx->fp);
+                WFCLOSE(ssh->fs, sendCtx->fp);
             }
 
             break;
@@ -2572,7 +2583,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
             if (ScpDirStackIsEmpty(sendCtx)) {
 
                 /* first request, keep track of request directory */
-                ret = ScpPushDir(sendCtx, peerRequest, ssh->ctx->heap);
+                ret = ScpPushDir(ssh->fs, sendCtx, peerRequest, ssh->ctx->heap);
 
                 if (ret == WS_SUCCESS) {
                     /* get file name from request */
@@ -2580,7 +2591,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
                 }
 
                 if (ret == WS_SUCCESS) {
-                    ret = GetFileStats(sendCtx, peerRequest, mTime, aTime,
+                    ret = GetFileStats(ssh->fs, sendCtx, peerRequest, mTime, aTime,
                                        fileMode);
                 }
 
@@ -2595,7 +2606,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
                 /* send directory msg or abort */
                 break;
             }
-            ret = FindNextDirEntry(sendCtx);
+            ret = FindNextDirEntry(ssh->fs, sendCtx);
 
             /* help out static analysis tool */
             if (ret != WS_BAD_ARGUMENT && sendCtx == NULL)
@@ -2609,7 +2620,7 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
                 /* reached end of directory */
                 if (sendCtx->entry == NULL) {
             #endif
-                    ret = ScpPopDir(sendCtx, ssh->ctx->heap);
+                    ret = ScpPopDir(ssh->fs, sendCtx, ssh->ctx->heap);
                     if (ret == WS_SUCCESS) {
                         ret = WS_SCP_EXIT_DIR;
 
@@ -2645,13 +2656,13 @@ int wsScpSendCallback(WOLFSSH* ssh, int state, const char* peerRequest,
                 break;
             }
 
-            ret = (word32)WFREAD(buf, 1, bufSz, sendCtx->fp);
+            ret = (word32)WFREAD(ssh->fs, buf, 1, bufSz, sendCtx->fp);
             if (ret == 0) { /* handle case of EOF */
                 ret = WS_EOF;
             }
 
             if ((ret <= 0) || (fileOffset + ret == *totalFileSz)) {
-                WFCLOSE(sendCtx->fp);
+                WFCLOSE(ssh->fs, sendCtx->fp);
             }
 
             break;
diff --git a/src/wolfsftp.c b/src/wolfsftp.c
index 47a2ac43a..253c9be26 100644
--- a/src/wolfsftp.c
+++ b/src/wolfsftp.c
@@ -1961,7 +1961,7 @@ int wolfSSH_SFTP_RecvOpen(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
         atr.per = 0644;
     }
 
-    fd = WOPEN(dir, m, atr.per);
+    fd = WOPEN(ssh->fs, dir, m, atr.per);
     if (fd < 0) {
         WLOG(WS_LOG_SFTP, "Error opening file %s", dir);
         res = oer;
@@ -2215,14 +2215,14 @@ int wolfSSH_SFTP_RecvOpenDir(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
         cur = (DIR_HANDLE*)WMALLOC(sizeof(DIR_HANDLE),
                 ssh->ctx->heap, DYNTYPE_SFTP);
         if (cur == NULL) {
-            WCLOSEDIR(&ctx);
+            WCLOSEDIR(ssh->fs, &ctx);
             return WS_MEMORY_E;
         }
         dirNameSz = (word32)WSTRLEN(dir) + 1;
         dirName = (char*)WMALLOC(dirNameSz,
                 ssh->ctx->heap, DYNTYPE_PATH);
         if (dirName == NULL) {
-            WCLOSEDIR(&ctx);
+            WCLOSEDIR(ssh->fs, &ctx);
             WFREE(cur, ssh->ctx->heap, DYNTYPE_SFTP);
             return WS_MEMORY_E;
         }
@@ -2613,7 +2613,7 @@ static int wolfSSH_SFTPNAME_readdir(WOLFSSH* ssh, WDIR* dir, WS_SFTPNAME* out,
         }
     }
 
-    if (!special && (WREADDIR(dir)) == NULL) {
+    if (!special && (WREADDIR(ssh->fs, dir)) == NULL) {
         ret = WS_NEXT_ERROR;
     }
 
@@ -2887,7 +2887,7 @@ static int wolfSSH_SFTPNAME_readdir(WOLFSSH* ssh, WDIR* dir, WS_SFTPNAME* out,
         return WS_BAD_ARGUMENT;
     }
 
-    dp = WREADDIR(dir);
+    dp = WREADDIR(ssh->fs, dir);
     if (dp == NULL) {
         return WS_FATAL_ERROR;
     }
@@ -3164,7 +3164,7 @@ int wolfSSH_SFTP_RecvCloseDir(WOLFSSH* ssh, byte* handle, word32 handleSz)
 #ifdef USE_WINDOWS_API
     FindClose(cur->dir);
 #else
-    WCLOSEDIR(&cur->dir);
+    WCLOSEDIR(ssh->fs, &cur->dir);
 #endif
 
     /* remove directory from list */
@@ -3247,7 +3247,7 @@ int wolfSSH_SFTP_RecvWrite(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
             return WS_BUFFER_E;
         }
 
-        ret = WPWRITE(fd, data + idx, sz, ofst);
+        ret = WPWRITE(ssh->fs, fd, data + idx, sz, ofst);
         if (ret < 0) {
     #if defined(WOLFSSL_NUCLEUS) && defined(DEBUG_WOLFSSH)
             if (ret == NUF_NOSPC) {
@@ -3424,7 +3424,7 @@ int wolfSSH_SFTP_RecvRead(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
         return WS_MEMORY_E;
     }
 
-    ret = WPREAD(fd, out + UINT32_SZ + WOLFSSH_SFTP_HEADER, sz, ofst);
+    ret = WPREAD(ssh->fs, fd, out + UINT32_SZ + WOLFSSH_SFTP_HEADER, sz, ofst);
     if (ret < 0 || (word32)ret > sz) {
         WLOG(WS_LOG_SFTP, "Error reading from file");
         res  = err;
@@ -3627,7 +3627,7 @@ int wolfSSH_SFTP_RecvClose(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
     if (sz == sizeof(WFD)) {
         WMEMSET((byte*)&fd, 0, sizeof(WFD));
         WMEMCPY((byte*)&fd, data + idx, sz);
-        ret = WCLOSE(fd);
+        ret = WCLOSE(ssh->fs, fd);
     #ifdef WOLFSSH_STOREHANDLE
         if (SFTP_RemoveHandleNode(ssh, data + idx, sz) != WS_SUCCESS) {
             WLOG(WS_LOG_SFTP, "Unable to remove handle from list");
@@ -4085,10 +4085,10 @@ int SFTP_GetAttributes(void* fs, const char* fileName, WS_SFTP_FILEATRB* atr,
     WOLFSSH_UNUSED(fs);
 
     if (noFollow) {
-        ret = WLSTAT(fileName, &stats);
+        ret = WLSTAT(ssh->fs, fileName, &stats);
     }
     else {
-        ret = WSTAT(fileName, &stats);
+        ret = WSTAT(ssh->fs, fileName, &stats);
     }
 
     WMEMSET(atr, 0, sizeof(WS_SFTP_FILEATRB));
@@ -4167,7 +4167,7 @@ int SFTP_GetAttributes_Handle(WOLFSSH* ssh, byte* handle, int handleSz,
         return WS_BAD_FILE_E;
     }
 
-    if (WSTAT(cur->name, &stats) != NU_SUCCESS) {
+    if (WSTAT(ssh->fs, cur->name, &stats) != NU_SUCCESS) {
         return WS_FATAL_ERROR;
     }
 
@@ -4507,12 +4507,12 @@ int SFTP_GetAttributes(void* fs, const char* fileName, WS_SFTP_FILEATRB* atr,
 
     if (noFollow) {
         /* Note, for windows, we treat WSTAT and WLSTAT the same. */
-        if (WLSTAT(fileName, &stats) != 0) {
+        if (WLSTAT(ssh->fs, fileName, &stats) != 0) {
             return WS_BAD_FILE_E;
         }
     }
     else {
-        if (WSTAT(fileName, &stats) != 0) {
+        if (WSTAT(ssh->fs, fileName, &stats) != 0) {
             return WS_BAD_FILE_E;
         }
     }
@@ -8098,9 +8098,9 @@ int wolfSSH_SFTP_Get(WOLFSSH* ssh, char* from,
                 WLOG(WS_LOG_SFTP, "SFTP GET STATE: OPEN LOCAL");
                 #ifndef USE_WINDOWS_API
                     if (state->gOfst[0] > 0 || state->gOfst[1] > 0)
-                        ret = WFOPEN(&state->fl, to, "ab");
+                        ret = WFOPEN(ssh->fs, &state->fl, to, "ab");
                     else
-                        ret = WFOPEN(&state->fl, to, "wb");
+                        ret = WFOPEN(ssh->fs, &state->fl, to, "wb");
                 #else /* USE_WINDOWS_API */
                     {
                         DWORD desiredAccess = GENERIC_WRITE;
@@ -8145,7 +8145,7 @@ int wolfSSH_SFTP_Get(WOLFSSH* ssh, char* from,
                     }
                     else {
                     #ifndef USE_WINDOWS_API
-                        if ((long)WFWRITE(state->r, 1,
+                        if ((long)WFWRITE(ssh->fs, state->r, 1,
                                           sz, state->fl) != sz) {
                             WLOG(WS_LOG_SFTP, "Error writing to file");
                             ssh->error = WS_BAD_FILE_E;
@@ -8207,7 +8207,7 @@ int wolfSSH_SFTP_Get(WOLFSSH* ssh, char* from,
             case STATE_GET_CLOSE_LOCAL:
                 WLOG(WS_LOG_SFTP, "SFTP GET STATE: CLOSE LOCAL");
                 #ifndef USE_WINDOWS_API
-                    WFCLOSE(state->fl);
+                    WFCLOSE(ssh->fs, state->fl);
                 #else /* USE_WINDOWS_API */
                     if (CloseHandle(state->fileHandle) == 0) {
                         WLOG(WS_LOG_SFTP, "Error closing file.");
@@ -8296,7 +8296,7 @@ int wolfSSH_SFTP_Put(WOLFSSH* ssh, char* from, char* to, byte resume,
             case STATE_PUT_OPEN_LOCAL:
                 WLOG(WS_LOG_SFTP, "SFTP PUT STATE: OPEN LOCAL");
             #ifndef USE_WINDOWS_API
-                ret = WFOPEN(&state->fl, from, "rb");
+                ret = WFOPEN(ssh->fs, &state->fl, from, "rb");
                 if (ret != 0) {
                     WLOG(WS_LOG_SFTP, "Unable to open input file");
                     ssh->error = WS_SFTP_FILE_DNE;
@@ -8310,7 +8310,7 @@ int wolfSSH_SFTP_Put(WOLFSSH* ssh, char* from, char* to, byte resume,
                 #if SIZEOF_OFF_T == 8
                     offset = (((word64)state->pOfst[1]) << 32) | offset;
                 #endif
-                    WFSEEK(state->fl, offset, 0);
+                    WFSEEK(ssh->fs, state->fl, offset, 0);
                 }
             #else /* USE_WINDOWS_API */
                 state->fileHandle = WS_CreateFileA(from, GENERIC_READ,
@@ -8355,7 +8355,7 @@ int wolfSSH_SFTP_Put(WOLFSSH* ssh, char* from, char* to, byte resume,
                 do {
                     if (state->rSz == 0) {
                     #ifndef USE_WINDOWS_API
-                        state->rSz = (int)WFREAD(state->r,
+                        state->rSz = (int)WFREAD(ssh->fs, state->r,
                                 1, WOLFSSH_MAX_SFTP_RW, state->fl);
                         if (state->rSz <= 0) {
                             break; /* either at end of file or error */
@@ -8399,7 +8399,7 @@ int wolfSSH_SFTP_Put(WOLFSSH* ssh, char* from, char* to, byte resume,
             case STATE_PUT_CLOSE_LOCAL:
                 WLOG(WS_LOG_SFTP, "SFTP PUT STATE: CLOSE LOCAL");
             #ifndef USE_WINDOWS_API
-                WFCLOSE(state->fl);
+                WFCLOSE(ssh->fs, state->fl);
             #else /* USE_WINDOWS_API */
                 CloseHandle(state->fileHandle);
             #endif /* USE_WINDOWS_API */
@@ -8450,7 +8450,7 @@ int wolfSSH_SFTP_free(WOLFSSH* ssh)
 
         /* go through and free handles and make sure files are closed */
         while (cur != NULL) {
-            WCLOSE(*((WFD*)cur->handle));
+            WCLOSE(ssh->fs, *((WFD*)cur->handle));
             if (SFTP_RemoveHandleNode(ssh, cur->handle, cur->handleSz)
                     != WS_SUCCESS) {
                 return WS_FATAL_ERROR;
@@ -8473,7 +8473,7 @@ int wolfSSH_SFTP_free(WOLFSSH* ssh)
         #ifdef USE_WINDOWS_API
             FindClose(toFree->dir);
         #else
-            WCLOSEDIR(&toFree->dir);
+            WCLOSEDIR(ssh->fs, &toFree->dir);
         #endif
             if (toFree->dirName != NULL)
                 WFREE(toFree->dirName, ssh->ctx->heap, DYNTYPE_SFTP);
diff --git a/wolfssh/port.h b/wolfssh/port.h
index ddbd7ed11..485ed0fbd 100644
--- a/wolfssh/port.h
+++ b/wolfssh/port.h
@@ -99,14 +99,14 @@ extern "C" {
     #define WFILE int
     WOLFSSH_API int wfopen(WFILE**, const char*, const char*);
 
-    #define WFOPEN(f,fn,m)    wfopen((f),(fn),(m))
-    #define WFCLOSE(f)        NU_Close(*(f))
-    #define WFWRITE(b,x,s,f)  ((s) != 0)? NU_Write(*(f),(const CHAR*)(b),(s)): 0
-    #define WFREAD(b,x,s,f)   NU_Read(*(f),(CHAR*)(b),(s))
-    #define WFSEEK(s,o,w)     NU_Seek(*(s),(o),(w))
-    #define WFTELL(s)         NU_Seek(*(s), 0, PSEEK_CUR)
-    #define WREWIND(s)        NU_Seek(*(s), 0, PSEEK_SET)
-    #define WSEEK_END         PSEEK_END
+    #define WFOPEN(fs, f,fn,m)  wfopen((f),(fn),(m))
+    #define WFCLOSE(fs,f)       NU_Close(*(f))
+    #define WFWRITE(fs,b,x,s,f) ((s) != 0)? NU_Write(*(f),(const CHAR*)(b),(s)): 0
+    #define WFREAD(fs,b,x,s,f)  NU_Read(*(f),(CHAR*)(b),(s))
+    #define WFSEEK(fs,s,o,w)    NU_Seek(*(s),(o),(w))
+    #define WFTELL(fs,s)        NU_Seek(*(s), 0, PSEEK_CUR)
+    #define WREWIND(fs,s)       NU_Seek(*(s), 0, PSEEK_SET)
+    #define WSEEK_END           PSEEK_END
 
     #define WS_DELIM '\\'
     #define WOLFSSH_O_RDWR   PO_RDWR
@@ -124,10 +124,10 @@ extern "C" {
         return NU_Open(f, PO_TEXT | flag, (PS_IWRITE | PS_IREAD));
     }
 
-    #define WOPEN(f,m,p) wOpen((f),(m),(p))
+    #define WOPEN(fs,f,m,p) wOpen((f),(m),(p))
 #endif
 
-    #define WCLOSE(fd) NU_Close((fd))
+    #define WCLOSE(fs,fd) NU_Close((fd))
 
     static inline int wChmod(const char* f, int mode) {
         unsigned char atr = 0;
@@ -176,13 +176,13 @@ extern "C" {
 
     WOLFSSH_API int wfopen(WFILE**, const char*, const char*);
 
-    #define WFOPEN(f,fn,m)      wfopen((f),(fn),(m))
-    #define WFCLOSE(f)          fclose((f))
-    #define WFREAD(b,s,a,f)     fread((b),(s),(a),(f))
-    #define WFWRITE(b,x,s,f)    fwrite((b),(x),(s),(f))
-    #define WFSEEK(s,o,w)       fseek((s),(o),(w))
-    #define WFTELL(s)           ftell((s))
-    #define WREWIND(s)          fseek((s), 0, IO_SEEK_SET)
+    #define WFOPEN(fs,f,fn,m)   wfopen((f),(fn),(m))
+    #define WFCLOSE(fs,f)       fclose((f))
+    #define WFREAD(fs,b,s,a,f)  fread((b),(s),(a),(f))
+    #define WFWRITE(fs,b,x,s,f) fwrite((b),(x),(s),(f))
+    #define WFSEEK(fs,s,o,w)    fseek((s),(o),(w))
+    #define WFTELL(fs,s)        ftell((s))
+    #define WREWIND(fs,s)       fseek((s), 0, IO_SEEK_SET)
     #define WSEEK_END           IO_SEEK_END
     #define WBADFILE            NULL
 
@@ -275,7 +275,7 @@ extern "C" {
         ret = f_open(*f, filename, m);
         return (int)ret;
     }
-    #define WFOPEN(f, fn, m) ff_fopen((f),(fn),(m))
+    #define WFOPEN(fs, f, fn, m) ff_fopen((f),(fn),(m))
 
 #ifdef WOLFSSH_XILFATFS
     static inline int ff_close(WFILE *f)
@@ -287,7 +287,7 @@ extern "C" {
     }
 #endif
 
-    #define WFCLOSE(f)  f_close(f)
+    #define WFCLOSE(fs,f)  f_close(f)
 
     static inline int ff_read(void *ptr, size_t size, size_t nmemb, WFILE *f)
     {
@@ -301,7 +301,7 @@ extern "C" {
         }
         return (n_bytes / size);
     }
-    #define WFREAD(b,s,a,f)  ff_read(b,s,a,f)
+    #define WFREAD(fs,b,s,a,f)  ff_read(b,s,a,f)
     static inline int ff_write(const void *ptr, size_t size, size_t nmemb, WFILE *f)
     {
         FRESULT ret;
@@ -314,9 +314,9 @@ extern "C" {
         }
         return (n_bytes / size);
     }
-    #define WFWRITE(b,s,a,f)  ff_write(b,s,a,f)
+    #define WFWRITE(fs,b,s,a,f)  ff_write(b,s,a,f)
 
-    #define WFTELL(s)   f_tell((s))
+    #define WFTELL(fs,s)   f_tell((s))
     static inline int ff_seek(WFILE *fp, long off, int whence)
     {
         switch(whence) {
@@ -333,17 +333,17 @@ extern "C" {
         }
         return -1;
     }
-    #define WFSEEK(s,o,w) ff_seek((s),(o),(w))
+    #define WFSEEK(fs,s,o,w) ff_seek((s),(o),(w))
 #ifdef WOLFSSH_XILFATFS
-    #define WREWIND(s) ff_seek(s, WSEEK_SET, 0)
+    #define WREWIND(fs,s) ff_seek(s, WSEEK_SET, 0)
 #else
-    #define WREWIND(s) f_rewind(s)
+    #define WREWIND(fs,s) f_rewind(s)
 #endif
     #define WBADFILE (-1)
     #ifndef NO_WOLFSSH_DIR
         #define WDIR DIR
         #define WOPENDIR(fs,h,c,d)  f_opendir((c),(d))
-        #define WCLOSEDIR(d)    f_closedir(d)
+        #define WCLOSEDIR(fs,d)    f_closedir(d)
     #endif
 #elif defined(WOLFSSH_USER_FILESYSTEM)
     /* User-defined I/O support */
@@ -355,15 +355,15 @@ extern "C" {
     #define WFILE FILE
     WOLFSSH_API int wfopen(WFILE**, const char*, const char*);
 
-    #define WFOPEN(f,fn,m)    wfopen((f),(fn),(m))
-    #define WFCLOSE(f)        fclose(f)
-    #define WFREAD(b,s,a,f)   fread((b),(s),(a),(f))
-    #define WFWRITE(b,s,a,f)  fwrite((b),(s),(a),(f))
-    #define WFSEEK(s,o,w)     fseek((s),(o),(w))
-    #define WFTELL(s)         ftell((s))
-    #define WREWIND(s)        rewind((s))
-    #define WSEEK_END         SEEK_END
-    #define WBADFILE          NULL
+    #define WFOPEN(fs,f,fn,m)   wfopen((f),(fn),(m))
+    #define WFCLOSE(fs,f)       fclose(f)
+    #define WFREAD(fs,b,s,a,f)  fread((b),(s),(a),(f))
+    #define WFWRITE(fs,b,s,a,f) fwrite((b),(s),(a),(f))
+    #define WFSEEK(fs,s,o,w)    fseek((s),(o),(w))
+    #define WFTELL(fs,s)        ftell((s))
+    #define WREWIND(fs,s)       rewind((s))
+    #define WSEEK_END           SEEK_END
+    #define WBADFILE            NULL
     #ifdef WOLFSSL_VXWORKS
         #define WUTIMES(f,t)      (WS_SUCCESS)
     #else
@@ -403,13 +403,13 @@ extern "C" {
 
             #ifndef _WIN32_WCE
                 #include <direct.h>
-                #define WCHDIR(p)      _chdir((p))
+                #define WCHDIR(fs,p)      _chdir((p))
                 #define WMKDIR(fs,p,m) _mkdir((p))
             #endif
         #else
             #include <unistd.h>
             #include <sys/stat.h>
-            #define WCHDIR(p)     chdir((p))
+            #define WCHDIR(fs,p)     chdir((p))
             #ifdef WOLFSSL_VXWORKS
                 #define WMKDIR(fs,p,m) mkdir((p))
             #else
@@ -529,8 +529,8 @@ extern "C" {
     #define WSTAT_T         struct stat
     #define WRMDIR(fs,d)   (NU_Remove_Dir((d)) == NU_SUCCESS)?0:1
     #define WMKDIR(fs,d,m) (NU_Make_Dir((d)) == NU_SUCCESS)?0:1
-    #define WSTAT(p,b)     NU_Get_First((b),(p))
-    #define WLSTAT(p,b)    NU_Get_First((b),(p))
+    #define WSTAT(fs,p,b)     NU_Get_First((b),(p))
+    #define WLSTAT(fs,p,b)    NU_Get_First((b),(p))
     #define WREMOVE(fs,d)  NU_Delete((d))
 
 #ifndef WS_MAX_RENAME_BUF
@@ -553,39 +553,39 @@ extern "C" {
             WFILE* fNew;
             unsigned char buf[WS_MAX_RENAME_BUF];
 
-            if ((ret = WFOPEN(&fOld, o, "rb")) != 0) {
+            if ((ret = WFOPEN(NULL, &fOld, o, "rb")) != 0) {
                 return ret;
             }
 
-            if ((ret = WFOPEN(&fNew, n, "rwb")) != 0) {
-                WFCLOSE(fOld);
+            if ((ret = WFOPEN(NULL, &fNew, n, "rwb")) != 0) {
+                WFCLOSE(NULL, fOld);
                 return ret;
             }
 
             /* read from the file in chunks and write chunks to new file */
             do {
-                ret = WFREAD(buf, 1, WS_MAX_RENAME_BUF, fOld);
+                ret = WFREAD(NULL, buf, 1, WS_MAX_RENAME_BUF, fOld);
                 if (ret > 0) {
-                    if ((WFWRITE(buf, 1, ret, fNew)) != ret) {
-                        WFCLOSE(fOld);
-                        WFCLOSE(fNew);
+                    if ((WFWRITE(NULL, buf, 1, ret, fNew)) != ret) {
+                        WFCLOSE(NULL, fOld);
+                        WFCLOSE(NULL, fNew);
                         WREMOVE(NULL, n);
                         return NUF_BADPARM;
                     }
                 }
             } while (ret > 0);
 
-            if (WFTELL(fOld) == WFSEEK(fOld, 0, WSEEK_END)) {
+            if (WFTELL(NULL, fOld) == WFSEEK(NULL, fOld, 0, WSEEK_END)) {
                 /* wrote everything from file */
-                WFCLOSE(fOld);
+                WFCLOSE(NULL, fOld);
                 WREMOVE(NULL, o);
-                WFCLOSE(fNew);
+                WFCLOSE(NULL, fNew);
             }
             else {
                 /* unable to write everything to file */
-                WFCLOSE(fNew);
+                WFCLOSE(NULL, fNew);
                 WREMOVE(NULL, n);
-                WFCLOSE(fOld);
+                WFCLOSE(NULL, fOld);
                 return NUF_BADPARM;
             }
 
@@ -634,7 +634,7 @@ extern "C" {
 
         return NU_Write(fd, (const CHAR*)buf, sz);
     }
-    #define WPWRITE(fd,b,s,o) wPwrite((fd),(b),(s),(o))
+    #define WPWRITE(fs,fd,b,s,o) wPwrite((fd),(b),(s),(o))
 #endif
 
 #ifndef WPREAD
@@ -648,7 +648,7 @@ extern "C" {
 
         return NU_Read(fd, (CHAR*)buf, sz);
     }
-    #define WPREAD(fd,b,s,o)  wPread((fd),(b),(s),(o))
+    #define WPREAD(fs,fd,b,s,o)  wPread((fd),(b),(s),(o))
 #endif
 
     static inline int wUtimes(const char* f, struct timeval t[2])
@@ -738,8 +738,8 @@ extern "C" {
     #define WOPENDIR(fs,h,c,d)  wOpenDir((c),(d))
 #endif
 
-    #define WCLOSEDIR(d) NU_Done((d))
-    #define WREADDIR(d)  (NU_Get_Next((d)) == NU_SUCCESS)?(d):NULL
+    #define WCLOSEDIR(fs,d) NU_Done((d))
+    #define WREADDIR(fs,d)  (NU_Get_Next((d)) == NU_SUCCESS)?(d):NULL
     #endif /* NO_WOLFSSH_DIR */
 
 #elif defined(FREESCALE_MQX)
@@ -801,7 +801,7 @@ extern "C" {
             return fopen(f, mode);
         }
 
-        #define WOPEN(f,m,p)    wOpen((f),(m),(p))
+        #define WOPEN(fs,f,m,p)    wOpen((f),(m),(p))
     #endif
 
     #ifndef WRMDIR
@@ -980,7 +980,7 @@ extern "C" {
         #define WGETCWD(fs,r,rSz)  wGetCwd((fs),(r),(rSz))
     #endif /* WGETCWD */
 
-    #define WCLOSE  fclose
+    #define WCLOSE(fs,fd)  fclose(fd)
 
     #ifndef WPWRITE
         static inline int wPwrite(WFD fd, unsigned char* buf, unsigned int sz,
@@ -995,7 +995,7 @@ extern "C" {
 
             return fwrite(buf, sz, 1, fd);
         }
-        #define WPWRITE(fd,b,s,o) wPwrite((fd),(b),(s),(o))
+        #define WPWRITE(fs,fd,b,s,o) wPwrite((fd),(b),(s),(o))
     #endif
 
 #ifndef WPREAD
@@ -1011,7 +1011,7 @@ extern "C" {
 
         return fread(buf, 1, sz, fd);
     }
-    #define WPREAD(fd,b,s,o)  wPread((fd),(b),(s),(o))
+    #define WPREAD(fs,fd,b,s,o)  wPread((fd),(b),(s),(o))
 #endif
 
 #ifndef NO_WOLFSSH_DIR
@@ -1109,7 +1109,7 @@ extern "C" {
 
             return 0;
         }
-        #define WCLOSEDIR(d)  wCloseDir((d))
+        #define WCLOSEDIR(fs,d)  wCloseDir((d))
     #endif /* WCLOSEDIR */
 #endif /* NO_WOLFSSH_DIR */
 
@@ -1117,10 +1117,10 @@ extern "C" {
     #define WSTAT_T FILINFO
 
     #define WRMDIR(fs, d) f_unlink((d))
-    #define WSTAT(p,b) f_stat(p,b)
-    #define WLSTAT(p,b) f_stat(p,b)
+    #define WSTAT(fs,p,b) f_stat(p,b)
+    #define WLSTAT(fs,p,b) f_stat(p,b)
     #define WREMOVE(fs,d) f_unlink((d))
-    #define WRENAME(fd,o,n) f_rename((o),(n))
+    #define WRENAME(fs,fd,o,n) f_rename((o),(n))
     #define WMKDIR(fs, p, m) f_mkdir(p)
     #define WFD int
 
@@ -1128,10 +1128,10 @@ extern "C" {
     int ff_close(int fd);
     int ff_pwrite(int fd, const byte *buffer, int sz);
     int ff_pread(int fd, byte *buffer, int sz);
-    #define WOPEN(f,m,p) ff_open(f,m,p)
-    #define WPWRITE(fd,b,s,o) ff_pwrite(fd,b,s)
-    #define WPREAD(fd,b,s,o)  ff_pread(fd,b,s)
-    #define WCLOSE(fd)  ff_close(fd)
+    #define WOPEN(fs,f,m,p) ff_open(f,m,p)
+    #define WPWRITE(fs,fd,b,s,o) ff_pwrite(fd,b,s)
+    #define WPREAD(fs,fd,b,s,o)  ff_pread(fd,b,s)
+    #define WCLOSE(fs,fd)  ff_close(fd)
 
     static inline int ff_chmod(const char *fname, int mode)
     {
@@ -1182,19 +1182,19 @@ extern "C" {
 
     #define WSTAT_T           struct _stat
     #define WRMDIR(fs,d)      _rmdir((d))
-    #define WSTAT(p,b)        _stat((p),(b))
-    #define WLSTAT(p,b)       _stat((p),(b))
+    #define WSTAT(fs,p,b)        _stat((p),(b))
+    #define WLSTAT(fs,p,b)       _stat((p),(b))
     #define WREMOVE(fs,d)     remove((d))
     #define WRENAME(fs,o,n)   rename((o),(n))
     #define WGETCWD(fs,r,rSz)    _getcwd((r),(rSz))
-    #define WOPEN(f,m,p)      _open((f),(m),(p))
-    #define WCLOSE(fd)        _close((fd))
+    #define WOPEN(fs,f,m,p)      _open((f),(m),(p))
+    #define WCLOSE(fs,fd)        _close((fd))
 
     #define WFD int
     int wPwrite(WFD, unsigned char*, unsigned int, const unsigned int*);
     int wPread(WFD, unsigned char*, unsigned int, const unsigned int*);
-    #define WPWRITE(fd,b,s,o) wPwrite((fd),(b),(s),(o))
-    #define WPREAD(fd,b,s,o)  wPread((fd),(b),(s),(o))
+    #define WPWRITE(fs,fd,b,s,o) wPwrite((fd),(b),(s),(o))
+    #define WPREAD(fs,fd,b,s,o)  wPread((fd),(b),(s),(o))
     #define WS_DELIM          '\\'
 
     #define WOLFSSH_O_RDWR    _O_RDWR
@@ -1221,11 +1221,11 @@ extern "C" {
 
     #define WSTAT_T      struct stat
     #define WRMDIR(fs,d) rmdir((d))
-    #define WSTAT(p,b)   stat((p),(b))
+    #define WSTAT(fs,p,b)   stat((p),(b))
     #ifndef USE_OSE_API
-        #define WLSTAT(p,b) lstat((p),(b))
+        #define WLSTAT(fs,p,b) lstat((p),(b))
     #else
-        #define WLSTAT(p,b) stat((p),(b))
+        #define WLSTAT(fs,p,b) stat((p),(b))
     #endif
     #define WREMOVE(fs,d)     remove((d))
     #define WRENAME(fs,o,n)   rename((o),(n))
@@ -1242,12 +1242,12 @@ extern "C" {
     #define WOLFSSH_O_TRUNC  O_TRUNC
     #define WOLFSSH_O_EXCL   O_EXCL
 
-    #define WOPEN(f,m,p) open((f),(m),(p))
-    #define WCLOSE(fd) close((fd))
+    #define WOPEN(fs,f,m,p) open((f),(m),(p))
+    #define WCLOSE(fs,fd) close((fd))
     int wPwrite(WFD, unsigned char*, unsigned int, const unsigned int*);
     int wPread(WFD, unsigned char*, unsigned int, const unsigned int*);
-    #define WPWRITE(fd,b,s,o) wPwrite((fd),(b),(s),(o))
-    #define WPREAD(fd,b,s,o)  wPread((fd),(b),(s),(o))
+    #define WPWRITE(fs,fd,b,s,o) wPwrite((fd),(b),(s),(o))
+    #define WPREAD(fs,fd,b,s,o)  wPread((fd),(b),(s),(o))
 
 #ifndef NO_WOLFSSH_DIR
     #include <dirent.h> /* used for opendir, readdir, and closedir */
@@ -1255,9 +1255,9 @@ extern "C" {
 
     /* returns 0 on success */
     #define WOPENDIR(fs,h,c,d)  ((*(c) = opendir((d))) == NULL)
-    #define WCLOSEDIR(d)  closedir(*(d))
-    #define WREADDIR(d)   readdir(*(d))
-    #define WREWINDDIR(d) rewinddir(*(d))
+    #define WCLOSEDIR(fs,d)  closedir(*(d))
+    #define WREADDIR(fs,d)   readdir(*(d))
+    #define WREWINDDIR(fs,d) rewinddir(*(d))
 #endif /* NO_WOLFSSH_DIR */
 #endif
 #endif /* WOLFSSH_SFTP or WOLFSSH_SCP */
diff --git a/wolfssh/test.h b/wolfssh/test.h
index 52062e9f0..eda5fe549 100644
--- a/wolfssh/test.h
+++ b/wolfssh/test.h
@@ -719,8 +719,8 @@ static INLINE int tcp_select(SOCKET_T socketfd, int to_sec)
             int depth, res;
             WFILE* file;
             for(depth = 0; depth <= MAX_WOLF_ROOT_DEPTH; depth++) {
-                if (WFOPEN(&file, serverKeyRsaPemFile, "rb") == 0) {
-                    WFCLOSE(file);
+                if (WFOPEN(NULL, &file, serverKeyRsaPemFile, "rb") == 0) {
+                    WFCLOSE(NULL, file);
                     return depth;
                 }
             #ifdef USE_WINDOWS_API