From c70dc7497eb4d39f0862e1476e535fb30748edff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arnim=20L=C3=A4uger?= <devsaurus@users.noreply.github.com>
Date: Sat, 19 Nov 2016 16:36:00 +0100
Subject: [PATCH] Handle error condition in file.read() (#1599)

* handle error condition in file.read()

* simplify loop initialization
---
 app/modules/file.c  | 18 +++++++++++-------
 app/spiffs/spiffs.c |  8 ++++++--
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/app/modules/file.c b/app/modules/file.c
index 66d3eeb7..3e9de55d 100644
--- a/app/modules/file.c
+++ b/app/modules/file.c
@@ -350,14 +350,18 @@ static int file_g_read( lua_State* L, int n, int16_t end_char, int fd )
 
   n = vfs_read(fd, p, n);
   // bypass search if no end character provided
-  for (i = end_char != EOF ? 0 : n; i < n; ++i)
-    if (p[i] == end_char)
-    {
-      ++i;
-      break;
-    }
+  if (n > 0 && end_char != EOF) {
+    for (i = 0; i < n; ++i)
+      if (p[i] == end_char)
+      {
+        ++i;
+        break;
+      }
+  } else {
+    i = n;
+  }
 
-  if (i == 0) {
+  if (i == 0 || n == VFS_RES_ERR) {
     if (heap_mem) {
       luaM_free(L, heap_mem);
       heap_mem = NULL;
diff --git a/app/spiffs/spiffs.c b/app/spiffs/spiffs.c
index 036118ee..3b71cc03 100644
--- a/app/spiffs/spiffs.c
+++ b/app/spiffs/spiffs.c
@@ -433,13 +433,17 @@ static sint32_t myspiffs_vfs_close( const struct vfs_file *fd ) {
 static sint32_t myspiffs_vfs_read( const struct vfs_file *fd, void *ptr, size_t len ) {
   GET_FILE_FH(fd);
 
-  return SPIFFS_read( &fs, fh, ptr, len );
+  sint32_t n = SPIFFS_read( &fs, fh, ptr, len );
+
+  return n >= 0 ? n : VFS_RES_ERR;
 }
 
 static sint32_t myspiffs_vfs_write( const struct vfs_file *fd, const void *ptr, size_t len ) {
   GET_FILE_FH(fd);
 
-  return SPIFFS_write( &fs, fh, (void *)ptr, len );
+  sint32_t n = SPIFFS_write( &fs, fh, (void *)ptr, len );
+
+  return n >= 0 ? n : VFS_RES_ERR;
 }
 
 static sint32_t myspiffs_vfs_lseek( const struct vfs_file *fd, sint32_t off, int whence ) {