General robustness and readability of onListFiles

Use constants for more magic numbers.
Ensure filename buffer is zeroed.
Avoid overrun of SCSI output buffer when max number of files is reached.
Only report as many bytes to write as actually filled in output.
Print additional debug messages.

src/Toolbox.cpp

@@ -105,112 +105,121 @@ static void doCountFiles(const char * dir_name, bool isCD = false)
 static void onListFiles(const char * dir_name, bool isCD = false) {
     FsFile dir;
     FsFile file;
+    const size_t ENTRY_SIZE = 40;
 
-    memset(scsiDev.data, 0, 4096);
-    int ENTRY_SIZE = 40;
+    memset(scsiDev.data, 0, ENTRY_SIZE * (MAX_FILE_LISTING_FILES + 1));
     char name[MAX_FILE_PATH] = {0};
+    uint8_t index = 0;
+    uint8_t file_entry[ENTRY_SIZE] = {0};
+
     dir.open(dir_name);
     dir.rewindDirectory();
-    uint8_t index = 0;
-    uint8_t file_entry[40] = {0};
     while (file.openNext(&dir, O_RDONLY))
     {   
+        memset(name, 0, sizeof(name));
+        // get base information
         uint8_t isDir = file.isDirectory() ? 0x00 : 0x01;
-        int len = file.getName(name, MAX_FILE_PATH);
-        if (len > MAX_MAC_PATH)
-            name[MAX_MAC_PATH] = 0x0;
+        size_t len = file.getName(name, MAX_FILE_PATH);
         uint64_t size = file.fileSize();
         file.close();
+        // truncate filename to fit in destination buffer
+        if (len > MAX_MAC_PATH)
+            name[MAX_MAC_PATH] = 0x0;
+        dbgmsg("TOOLBOX LIST FILES: truncated filename is '", name, "'");
+        // validate file is allowed for this listing
         if (!toolboxFilenameValid(name, isCD))
             continue;
         if (isCD && isDir == 0x00)
             continue;
+        // fill output buffer
         file_entry[0] = index;
         file_entry[1] = isDir;
-        int c = 0; // Index of char in name[]
-
-        for(int i = 2; i < (MAX_MAC_PATH + 1 + 2); i++) {   // bytes 2 - 34
-            file_entry[i] = name[c++];
+        for(int i = 0; i < MAX_MAC_PATH + 1 ; i++) {
+            file_entry[i + 2] = name[i];   // bytes 2 - 34
         }
         file_entry[35] = 0; //(size >> 32) & 0xff;
         file_entry[36] = (size >> 24) & 0xff;
         file_entry[37] = (size >> 16) & 0xff;
         file_entry[38] = (size >> 8) & 0xff;
         file_entry[39] = (size) & 0xff;
+        // send to SCSI output buffer
         memcpy(&(scsiDev.data[ENTRY_SIZE * index]), file_entry, ENTRY_SIZE);
+        // increment index
         index = index + 1;
+        if (index >= MAX_FILE_LISTING_FILES) break;
     }
     dir.close();
 
-    scsiDev.dataLen = 4096;
+    scsiDev.dataLen = ENTRY_SIZE * index;
     scsiDev.phase = DATA_IN;
+    dbgmsg("TOOLBOX LIST FILES: returning ", index, " files for size ", scsiDev.dataLen);
 }
 
 static FsFile get_file_from_index(uint8_t index, const char * dir_name, bool isCD = false)
 {
-  FsFile dir;
-  FsFile file_test;
-  char name[MAX_FILE_PATH] = {0};
+    FsFile dir;
+    FsFile file_test;
+    char name[MAX_FILE_PATH] = {0};
 
-  dir.open(dir_name);
-  dir.rewindDirectory(); // Back to the top
-  int count = 0;
-  while (file_test.openNext(&dir, O_RDONLY))
-  {
-    // If error there is no next file to open.
-    if(file_test.getError() > 0) {
-      file_test.close();
-      break;
-    }
-        // no directories in CD image listing
-    if (isCD && file_test.isDirectory())
+    dir.open(dir_name);
+    dir.rewindDirectory(); // Back to the top
+    int count = 0;
+    while (file_test.openNext(&dir, O_RDONLY))
     {
-        file_test.close();
-        continue;
-    }
+        // If error there is no next file to open.
+        if(file_test.getError() > 0) {
+            file_test.close();
+            break;
+        }
+        // no directories in CD image listing
+        if (isCD && file_test.isDirectory())
+        {
+            file_test.close();
+            continue;
+        }
         // truncate filename the same way listing does, before validating name
         size_t len = file_test.getName(name, MAX_FILE_PATH);
         if (len > MAX_MAC_PATH)
             name[MAX_MAC_PATH] = 0x0;
         // validate filename
-    if(!toolboxFilenameValid(name, isCD))
-    {
-        file_test.close();
-        continue;
-    }
+        if(!toolboxFilenameValid(name, isCD))
+        {
+            file_test.close();
+            continue;
+        }
         // found file?
-    if (count == index)
-    {
-      dir.close();
-      return file_test;
-    }
-    else
-    {
-      file_test.close();
+        if (count == index)
+        {
+            dir.close();
+            return file_test;
+        }
+        else
+        {
+            file_test.close();
+        }
+        count++;
     }
-    count++;
-  }
-  file_test.close();
-  dir.close();
-  return file_test;
+    file_test.close();
+    dir.close();
+    return file_test;
 }
 
 // Devices that are active on this SCSI device.
 static void onListDevices()
 {
-  for (int i = 0; i < NUM_SCSIID; i++)
-  {
-    const S2S_TargetCfg* cfg = s2s_getConfigById(i);
-    if (cfg && (cfg->scsiId & S2S_CFG_TARGET_ENABLED))
-    {
-        scsiDev.data[i] = (int)cfg->deviceType; // 2 == cd
-    }
-    else
+    for (int i = 0; i < NUM_SCSIID; i++)
     {
-        scsiDev.data[i] = 0xFF; // not enabled target.
+        const S2S_TargetCfg* cfg = s2s_getConfigById(i);
+        if (cfg && (cfg->scsiId & S2S_CFG_TARGET_ENABLED))
+        {
+            scsiDev.data[i] = (int)cfg->deviceType; // 2 == cd
+        }
+        else
+        {
+            scsiDev.data[i] = 0xFF; // not enabled target.
+        }
     }
-  }
-  scsiDev.dataLen = NUM_SCSIID;
+    scsiDev.dataLen = NUM_SCSIID;
 }
 
 static void onSetNextCD(const char * img_dir)