ppapi/native_client/src/trusted/plugin/file_utils.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Some common file utilities for plugin code.
   6
   7 #include "ppapi/native_client/src/trusted/plugin/file_utils.h"
   8
   9 #include <fcntl.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15
  16 #include "native_client/src/include/nacl_scoped_ptr.h"
  17 #include "native_client/src/include/portability_io.h"
  18 #include "native_client/src/include/portability_string.h"
  19
  20
  21 namespace plugin {
  22 namespace file_utils {
  23
  24 StatusCode SlurpFile(int32_t fd,
  25                      nacl::string& out_buf,
  26                      size_t max_size_to_read) {
  27   struct stat stat_buf;
  28   if (fstat(fd, &stat_buf) != 0) {
  29     CLOSE(fd);
  30     return PLUGIN_FILE_ERROR_STAT;
  31   }
  32
  33   // Figure out how large a buffer we need to slurp the whole file (with a
  34   // '\0' at the end).
  35   size_t bytes_to_read = static_cast<size_t>(stat_buf.st_size);
  36   if (bytes_to_read > max_size_to_read - 1) {
  37     CLOSE(fd);
  38     return PLUGIN_FILE_ERROR_FILE_TOO_LARGE;
  39   }
  40
  41   FILE* input_file = fdopen(fd, "rb");
  42   if (!input_file) {
  43     CLOSE(fd);
  44     return PLUGIN_FILE_ERROR_OPEN;
  45   }
  46   // From here on, closing input_file will automatically close fd.
  47
  48   nacl::scoped_array<char> buffer(new char[bytes_to_read + 1]);
  49   if (buffer == NULL) {
  50     fclose(input_file);
  51     return PLUGIN_FILE_ERROR_MEM_ALLOC;
  52   }
  53
  54   size_t total_bytes_read = 0;
  55   while (bytes_to_read > 0) {
  56     size_t bytes_this_read = fread(&buffer[total_bytes_read],
  57                                    sizeof(char),
  58                                    bytes_to_read,
  59                                    input_file);
  60     if (bytes_this_read < bytes_to_read && (feof(input_file) ||
  61                                             ferror(input_file))) {
  62       fclose(input_file);
  63       return PLUGIN_FILE_ERROR_READ;
  64     }
  65     total_bytes_read += bytes_this_read;
  66     bytes_to_read -= bytes_this_read;
  67   }
  68
  69   fclose(input_file);
  70   buffer[total_bytes_read] = '\0';
  71   out_buf = buffer.get();
  72   return PLUGIN_FILE_SUCCESS;
  73 }
  74
  75 }  // namespace file_utils
  76 }  // namespace plugin
  77