xref: /external/google-breakpad/src/common/linux/safe_readlink.cc

// Copyright (c) 2011, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// safe_readlink.cc: Implement google_breakpad::SafeReadLink.
// See safe_readlink.h for details.

#include <stddef.h>

#include "third_party/lss/linux_syscall_support.h"

namespace google_breakpad {

bool SafeReadLink(const char* path, char* buffer, size_t buffer_size) {
  // sys_readlink() does not add a NULL byte to |buffer|. In order to return
  // a NULL-terminated string in |buffer|, |buffer_size| should be at least
  // one byte longer than the expected path length. Also, sys_readlink()
  // returns the actual path length on success, which does not count the
  // NULL byte, so |result_size| should be less than |buffer_size|.
  ssize_t result_size = sys_readlink(path, buffer, buffer_size);
  if (result_size >= 0 && static_cast<size_t>(result_size) < buffer_size) {
    buffer[result_size] = '\0';
    return true;
  }
  return false;
}

}  // namespace google_breakpad