Chrome的奇怪的“ gpu-preferences”

Question

在计算机上执行ps -ef时，我发现一个非常奇怪/特殊的命令行参数chrome：

501   536   493   0 二11上午 ??       13:11.48 /Applications/Google Chrome.app/Contents/Versions/69.0.3497.100/Google Chrome Helper.app/Contents/MacOS/Google Chrome Helper --type=gpu-process --field-trial-handle=3535656472344341962,3817030915272013891,131072 --gpu-preferences=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 --service-request-channel-token=17030867567105907743

出于好奇，我发现source of chromium似乎很正常：

namespace gl {
// On dual-GPU systems, expresses a preference for using the integrated
// or discrete GPU. On systems that have dual-GPU support (see
// GpuDataManagerImpl), resource sharing only works between
// contexts that are created with the same GPU preference.
//
// This API will likely need to be adjusted as the functionality is
// implemented on more operating systems.
enum GpuPreference {
  GpuPreferenceNone,
  PreferIntegratedGpu,
  PreferDiscreteGpu,
  GpuPreferenceLast = PreferDiscreteGpu
};
}  // namespace gl

因此，该参数（KAAAA....）是否被遮盖或GPU名称的某种编码？为什么会有这么奇怪的编码？

Answer 1

每当您看到其中包含大量AAAA的编码时，您可以打赌它是二进制文件的Base64编码，其中包含许多空值。

>>> a=b'KAAAAAAAAAQAAAAAAAAAAAGAAAAAAAAAAAAAIAAAAAAAAADgBAAAmAAAAM=='
>>> base64.b64decode(a).hex()
'2800000000000004000000000000000001800000000000000000002000000000000000e004000098000000'

（更笼统地说，任何同时使用大写和小写字母的编码都可能是Base64。例如，与SHA1的十六进制相比，在Base64中通常会给出SHA256。）

这对应于以下接口：https://cs.chromium.org/chromium/src/gpu/ipc/common/gpu_preferences.mojom

接线格式似乎没有很多文献记录，因此，如果您要解释该值，最好检查一下铬树并构建绑定生成器。 https://chromium.googlesource.com/chromium/src/+/master/mojo/public/tools/bindings/README.md