POSIX File Server Backend

2026-10-10 11:38:52 +08:00 · 2015-05-19 17:47:37 -10:00
parent 228785b8f8
commit ee25e3db45
1 changed files with 180 additions and 0 deletions
@@ -0,0 +1,180 @@
+/****************************************************************************
+*
+*   Copyright (c) 2015 PX4 Development Team. All rights reserved.
+*      Author: Pavel Kirienko <pavel.kirienko@gmail.com>
+*              David Sidrane <david_s5@usa.net>
+*
+****************************************************************************/
+
+#ifndef UAVCAN_POSIX_FILE_SERVER_BACKEND_HPP_INCLUDED
+#define UAVCAN_POSIX_FILE_SERVER_BACKEND_HPP_INCLUDED
+
+#include <sys/stat.h>
+#include <cstdio>
+#include <cstddef>
+#include <cstdlib>
+#include <cstring>
+#include <cerrno>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <uavcan/data_type.hpp>
+#include <uavcan/protocol/file/EntryType.hpp>
+#include <uavcan/protocol/file/Read.hpp>
+#include <uavcan/protocol/file_server.hpp>
+
+namespace uavcan_posix
+{
+/**
+ * This interface implements a POSIX compliant IFileServerBackend interface
+ */
+class FileSeverBackend : public uavcan::IFileServerBackend
+{
+  /**
+   * Maximum length of full path including / the file name
+   */
+  enum { MaxPathLength =  Path::MaxSize + 128 };
+
+  enum { FilePermissions = 438 };     ///< 0o666
+
+  /**
+   * This type is used for the path
+   */
+  typedef uavcan::MakeString<MaxPathLength>::Type PathString;
+
+  PathString base_path;
+
+public:
+  /**
+   *
+   * Backend for uavcan.protocol.file.GetInfo.
+   * Implementation of this method is required.
+   * On success the method must return zero.
+   */
+    virtual int16_t getInfo(const Path& path, uint64_t& out_crc64, uint32_t& out_size, EntryType& out_type)
+    {
+
+      enum { MaxBufferLength = 256 };
+
+      int rv = -uavcan::ErrInvalidParam;
+      if (path.size()) {
+
+        rv = -uavcan::ErrFailure;
+
+        PathString root_path = base_path.c_str();
+        root_path += path;
+
+        uint32_t size = 0;
+        int fd = open(path.c_str(), O_RDONLY);
+        if (fd >= 0)
+        {
+            uavcan::DataTypeSignatureCRC crc;
+            ssize_t len;
+
+            uint8_t bytes[MaxBufferLength];
+
+            do {
+
+              len = ::read(fd, bytes, MaxBufferLength);
+
+              if (len <  0) {
+                  return rv;
+              }
+
+              if (len >  0) {
+                size += len;
+                crc.add(bytes, len);
+              }
+
+            } while(len);
+
+            out_crc64 = crc.get();
+            out_size = size;
+            EntryType t;
+            t.flags = uavcan::protocol::file::EntryType::FLAG_FILE;
+            out_type = t;
+            rv = 0;
+        }
+      }
+      return rv;
+    }
+
+    /**
+     * Backend for uavcan.protocol.file.Read.
+     * Implementation of this method is required.
+     * @ref inout_size is set to @ref ReadSize; read operation is required to return exactly this amount, except
+     * if the end of file is reached.
+     * On success the method must return zero.
+     */
+      virtual int16_t read(const Path& path, const uint32_t offset, uint8_t* out_buffer, uint16_t& inout_size)
+      {
+
+          int rv = -uavcan::ErrInvalidParam;
+
+          if (path.size()) {
+
+            rv = -uavcan::ErrFailure;
+
+            PathString root_path = base_path.c_str();
+            root_path += path;
+
+            int fd = open(path.c_str(), O_RDONLY);
+
+            if (fd >= 0)
+            {
+                if (::lseek(fd, offset, SEEK_SET) >= 0) {
+
+                    ssize_t len  = ::read(fd, out_buffer, inout_size);
+
+                  if (len <  0) {
+                      return rv;
+                  }
+                  inout_size =  len;
+                  rv = 0;
+                }
+            }
+          }
+        return rv;
+      }
+
+    /**
+     * Initializes the file serrver based backend storage by passing a path to
+     * the directory where files will be stored.
+     */
+    int init(const PathString& path)
+    {
+        using namespace std;
+
+        int rv = -uavcan::ErrInvalidParam;
+
+        if (path.size() > 0)
+        {
+            base_path = path.c_str();
+
+            if (base_path.back() == '/')
+            {
+                base_path.pop_back();
+            }
+
+            rv = 0;
+            struct stat sb;
+            if (stat(base_path.c_str(), &sb) != 0 || !S_ISDIR(sb.st_mode))
+            {
+                rv = mkdir(base_path.c_str(), S_IRWXU | S_IRWXG | S_IRWXO);
+            }
+            if (rv >= 0 )
+            {
+                base_path.push_back('/');
+                if ((base_path.size() + Path::MaxSize) > MaxPathLength)
+                {
+                    rv = -uavcan::ErrInvalidConfiguration;
+                }
+            }
+        }
+        return rv;
+    }
+};
+
+}
+
+#endif // Include guard