From 73445fdae95b35a57bacc046187be55c8ad2bfa1 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sat, 30 May 2015 22:16:22 +1000
Subject: [PATCH] DataFlash: added error checking and fixed a warning

---
 libraries/DataFlash/DataFlash.h         |  2 +-
 libraries/DataFlash/DataFlash_Block.cpp | 19 ++++++++++++++-----
 libraries/DataFlash/DataFlash_Block.h   |  2 +-
 libraries/DataFlash/DataFlash_File.cpp  |  9 ++++++---
 libraries/DataFlash/DataFlash_File.h    |  2 +-
 libraries/DataFlash/LogFile.cpp         |  8 ++++++--
 6 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/libraries/DataFlash/DataFlash.h b/libraries/DataFlash/DataFlash.h
index 0fa9504c71..1732c59bce 100644
--- a/libraries/DataFlash/DataFlash.h
+++ b/libraries/DataFlash/DataFlash.h
@@ -135,7 +135,7 @@ protected:
     /*
       read a block
     */
-    virtual void ReadBlock(void *pkt, uint16_t size) = 0;
+    virtual bool ReadBlock(void *pkt, uint16_t size) = 0;
 
 };
 
diff --git a/libraries/DataFlash/DataFlash_Block.cpp b/libraries/DataFlash/DataFlash_Block.cpp
index b3d167bbea..6f0b0eeacc 100644
--- a/libraries/DataFlash/DataFlash_Block.cpp
+++ b/libraries/DataFlash/DataFlash_Block.cpp
@@ -104,7 +104,7 @@ void DataFlash_Block::StartRead(uint16_t PageAdr)
     df_Read_BufferIdx = sizeof(ph);
 }
 
-void DataFlash_Block::ReadBlock(void *pBuffer, uint16_t size)
+bool DataFlash_Block::ReadBlock(void *pBuffer, uint16_t size)
 {
     while (size > 0) {
         uint16_t n = df_PageSize - df_Read_BufferIdx;
@@ -114,7 +114,9 @@ void DataFlash_Block::ReadBlock(void *pBuffer, uint16_t size)
 
         WaitReady();
 
-        BlockRead(df_Read_BufferNum, df_Read_BufferIdx, pBuffer, n);
+        if (!BlockRead(df_Read_BufferNum, df_Read_BufferIdx, pBuffer, n)) {
+            return false;
+        }
         size -= n;
         pBuffer = (void *)(n + (uintptr_t)pBuffer);
         
@@ -129,13 +131,16 @@ void DataFlash_Block::ReadBlock(void *pBuffer, uint16_t size)
 
             // We are starting a new page - read FileNumber and FilePage
             struct PageHeader ph;
-            BlockRead(df_Read_BufferNum, 0, &ph, sizeof(ph));
+            if (!BlockRead(df_Read_BufferNum, 0, &ph, sizeof(ph))) {
+                return false;
+            }
             df_FileNumber = ph.FileNumber;
             df_FilePage   = ph.FilePage;
 
             df_Read_BufferIdx = sizeof(ph);
         }
     }
+    return true;
 }
 
 void DataFlash_Block::SetFileNumber(uint16_t FileNumber)
@@ -182,7 +187,9 @@ bool DataFlash_Block::NeedErase(void)
 {
     uint32_t version = 0;
     StartRead(df_NumPages+1);
-    ReadBlock(&version, sizeof(version));
+    if (!ReadBlock(&version, sizeof(version))) {
+        return true;
+    }
     StartRead(1);
     return version != DF_LOGGING_FORMAT;
 }
@@ -207,7 +214,9 @@ int16_t DataFlash_Block::get_log_data_raw(uint16_t log_num, uint16_t page, uint3
     }
 
     df_Read_BufferIdx = offset + sizeof(struct PageHeader);
-    ReadBlock(data, len);
+    if (!ReadBlock(data, len)) {
+        return -1;
+    }
 
     return (int16_t)len;
 }
diff --git a/libraries/DataFlash/DataFlash_Block.h b/libraries/DataFlash/DataFlash_Block.h
index 85563bc18f..2ab1ee1d4d 100644
--- a/libraries/DataFlash/DataFlash_Block.h
+++ b/libraries/DataFlash/DataFlash_Block.h
@@ -93,7 +93,7 @@ private:
     void FinishWrite(void);
 
     // Read methods
-    void ReadBlock(void *pBuffer, uint16_t size);
+    bool ReadBlock(void *pBuffer, uint16_t size);
 
     // file numbers
     void SetFileNumber(uint16_t FileNumber);
diff --git a/libraries/DataFlash/DataFlash_File.cpp b/libraries/DataFlash/DataFlash_File.cpp
index 5d2109bbbb..5e8759b9bd 100644
--- a/libraries/DataFlash/DataFlash_File.cpp
+++ b/libraries/DataFlash/DataFlash_File.cpp
@@ -229,15 +229,18 @@ void DataFlash_File::WriteBlock(const void *pBuffer, uint16_t size)
 /*
   read a packet. The header bytes have already been read.
 */
-void DataFlash_File::ReadBlock(void *pkt, uint16_t size)
+bool DataFlash_File::ReadBlock(void *pkt, uint16_t size)
 {
     if (_read_fd == -1 || !_initialised || _open_error) {
-        return;
+        return false;
     }
 
     memset(pkt, 0, size);
-    ::read(_read_fd, pkt, size);
+    if (::read(_read_fd, pkt, size) != size) {
+        return false;
+    }
     _read_offset += size;
+    return true;
 }
 
 
diff --git a/libraries/DataFlash/DataFlash_File.h b/libraries/DataFlash/DataFlash_File.h
index 373ad4164c..53b4ab6f94 100644
--- a/libraries/DataFlash/DataFlash_File.h
+++ b/libraries/DataFlash/DataFlash_File.h
@@ -64,7 +64,7 @@ private:
     /*
       read a block
     */
-    void ReadBlock(void *pkt, uint16_t size);
+    bool ReadBlock(void *pkt, uint16_t size);
 
     // write buffer
     uint8_t *_writebuf;
diff --git a/libraries/DataFlash/LogFile.cpp b/libraries/DataFlash/LogFile.cpp
index aa2425d05a..7f519b200d 100644
--- a/libraries/DataFlash/LogFile.cpp
+++ b/libraries/DataFlash/LogFile.cpp
@@ -292,7 +292,9 @@ void DataFlash_Class::_print_log_entry(uint8_t msg_type,
     }
     uint8_t msg_len = PGM_UINT8(&_structures[i].msg_len) - 3;
     uint8_t pkt[msg_len];
-    ReadBlock(pkt, msg_len);
+    if (!ReadBlock(pkt, msg_len)) {
+        return;
+    }
     port->printf_P(PSTR("%S, "), _structures[i].name);
     for (uint8_t ofs=0, fmt_ofs=0; ofs<msg_len; fmt_ofs++) {
         char fmt = PGM_UINT8(&_structures[i].format[fmt_ofs]);
@@ -469,7 +471,9 @@ void DataFlash_Block::LogReadProcess(uint16_t log_num,
 
     while (true) {
         uint8_t data;
-        ReadBlock(&data, 1);
+        if (!ReadBlock(&data, 1)) {
+            break;
+        }
 
         // This is a state machine to read the packets
         switch(log_step) {