initial code commit

src/read.cpp

@@ -0,0 +1,94 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <fuse.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <string>
+#include <algorithm>
+
+#include "config.hpp"
+#include "ugid.hpp"
+#include "fileinfo.hpp"
+
+using std::string;
+
+static
+int
+_read_controlfile(const string  readstr,
+                  char         *buf,
+                  const size_t  count)
+{
+  size_t n;
+
+  n = std::min(count,readstr.length());
+
+  memcpy(buf,readstr.data(),n);
+
+  return (int)n;
+}
+
+static
+int
+_read(const int     fd,
+      void         *buf,
+      const size_t  count,
+      const off_t   offset)
+{
+  int rv;
+
+  rv = ::pread(fd,buf,count,offset);
+
+  return ((rv == -1) ? -errno : rv);
+}
+
+namespace mergerfs
+{
+  namespace read
+  {
+    int
+    read(const char            *fusepath,
+         char                  *buf,
+         size_t                 count,
+         off_t                  offset,
+         struct fuse_file_info *fi)
+    {
+      const ugid::SetResetGuard  ugid;
+      const config::Config      &config = config::get();
+
+      if(fusepath == config.controlfile)
+        return _read_controlfile(config.readstr,
+                                 buf,
+                                 count);
+
+      return _read(((FileInfo*)fi->fh)->fd,
+                   buf,
+                   count,
+                   offset);
+    }
+  }
+}