2c7b71db56
When semodule -i some.pp to install a module package, duplicate items are detected for the module. The detection function is nodups_specs in libselinux/src/label_file.c. The algorithm complexity of implementing this function is O(M*(N^2)). M is a symbol related to the length of a string. N indicates the number of data->nspec. In scenarios where N is very large, the efficiency is very low. To solve this problem, I propose to use the hash table to detect duplicates. The algorithm complexity of new implementing is O(M*N). The execution efficiency will be greatly improved. Comparison between the execution time of the nodups_specs function. Old double-layer loop implementation O(M*(N^2)): semodule -i myapp1.pp nodups_specs data->nspec: 5002 nodups_specs start: 11785.242s nodups_specs end: 11785.588s nodups_specs consumes: 0.346s semodule -i myapp2.pp nodups_specs data->nspec: 10002 nodups_specs start: 11804.280s nodups_specs end: 11806.546s nodups_specs consumes: 2.266s semodule -i myapp3.pp nodups_specs data->nspec: 20002 nodups_specs start: 11819.106s nodups_specs end: 11830.892s nodups_specs consumes: 11.786s New hash table implementation O(M*N): semodule -i myapp1.pp nodups_specs data->nspec: 5002 nodups_specs start: 11785.588s nodups_specs end: 11785.590s nodups_specs consumes: 0.002s semodule -i myapp2.pp nodups_specs data->nspec: 10002 nodups_specs start: 11806.546s nodups_specs end: 11806.552s nodups_specs consumes: 0.006s semodule -i myapp3.pp nodups_specs data->nspec: 20002 nodups_specs start: 11830.892s nodups_specs end: 11830.905s nodups_specs consumes: 0.013s Signed-off-by: wanghuizhao <wanghuizhao1@huawei.com> Acked-by: James Carter <jwcart2@gmail.com> |
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