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说明

系统：Android10.0

设备： FireFly RK3399 （ROC-RK3399-PC-PLUS）

前言

本章节重点介绍在Android源码中如何编译selinux模块， 以及如何查看编译日志

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一， selinux编译方法

修改了*.te，可以选择模块编译，也可以全编译。

make selinux_policy	编译system/sepolicy/Android.mk中selinux_policy目标， 基本上也将Android.mk中大部分目标都编译了
mmma  system/sepolicy	针对system/sepolicy/Android.mk所有目标文件进行编译
make precompiled_sepolicy	编译最终二进制文件precompiled_sepolicy，生成在  $(OUT_TARGET)/vendor/etc/selinux/precompiled_sepolicy 或者：$(OUT_TARGET)/odm/etc/selinux/precompiled_sepolicy 替换到板子即可
查看verbose日志	./prebuilts/build-tools/linux-x86/bin/ninja -v -f out/combined-rk3399_roc_pc_plus.ninja  selinux_policy 日志会显示很多内容

操作例子：修改 device/rockchip/common/sepolicy/vendor/genfs_contexts

# rk3399

genfscon sysfs /devices/platform/fe330000.sdhci                                                     u:object_r:sysfs_mmc:s0

genfscon sysfs /devices/platform/fe43000.sdhci                                                     u:object_r:sysfs_mmc:s0

修改完成之后，就可以执行make selinux_policy来编译

该命令默认终端不会输出太多显示日志， 可以查看verbose文件： vim out/verbose.log.gz，以下日志只是摘抄一部分日志：

[537/608] /bin/bash -c "m4 --fatal-warnings  -D mls_num_sens=1 -D mls_num_cats=1024 -D target_build_variant=userdebug -D target_with_dexpreopt=true -D target_arch=arm64 -D target_with_asan=false -D target_with_native_coverage=false -D target_full_treble=true -D target_compatible_property=true -D target_exclude_build_test=  -s system/sepolicy/reqd_mask/security_classes system/sepolicy/reqd_mask/initial_sids system/sepolicy/reqd_mask/access_vectors system/sepolicy/reqd_mask/mls_macros system/sepolicy/reqd_mask/mls_decl system/sepolicy/reqd_mask/mls system/sepolicy/reqd_mask/reqd_mask.te system/sepolicy/reqd_mask/roles_decl system/sepolicy/reqd_mask/roles system/sepolicy/reqd_mask/users system/sepolicy/reqd_mask/initial_sid_contexts　> out/target/product/rk3399_roc_pc_plus/obj/ETC/sepolicy_neverallows_intermediates/reqd_policy_mask.conf"
[538/608] /bin/bash -c "ASAN_OPTIONS=detect_leaks=0 out/host/linux-x86/bin/checkpolicy -C -M -c         30 -o out/target/product/rk3399_roc_pc_plus/obj/ETC/sepolicy_neverallows_intermediates/reqd_policy_mask.cil 

以上日志，可以参考上一章节简介编译流程，来看日志。

二，　sepoliy文件编译的逻辑

以上逻辑就是：平台的相关策略文件会被编译到system分区中的etc/selinux中， 非平台的策略文件会被编译到vendor, odm分区中的etc/selinux中。

三， 编译出来的中间文件

编译的时候， 会产生中间文件和目录， 通过查看中间文件目录里面的xx.tmp文件就知道最终目标是由那些源文件合并而来。如

out/target/product/rk3399_roc_pc_plus/obj/ETC/plat_file_contexts_intermediates/plat_file_contexts.tmp

#line 1 "system/sepolicy/private/file_contexts"
###########################################
# Root
/                   u:object_r:rootfs:s0

# Data files
/adb_keys           u:object_r:adb_keys_file:s0
/build\.prop        u:object_r:rootfs:s0
/default\.prop      u:object_r:rootfs:s0
/fstab\..*          u:object_r:rootfs:s0
/init\..*           u:object_r:rootfs:s0
/res(/.*)?          u:object_r:rootfs:s0
/selinux_version    u:object_r:rootfs:s0
/ueventd\..*        u:object_r:rootfs:s0
/verity_key         u:object_r:rootfs:s0
.......

#line 1 "device/rockchip/common/sepolicy/private/file_contexts"
# file in /system
/system/bin/move_widevine_data\.sh              u:object_r:move-widevine-data-sh_exec:s0
#line 1 "out/target/product/rk3399_roc_pc_plus/obj/ETC/sectxfile_nl_intermediates/sectxfile_nl"

#line 1 "system/sepolicy/private/file_contexts_overlayfs"
#############################
# Overlayfs support directories for userdebug/eng devices
#
/cache/overlay/(system|product)/upper       u:object_r:system_file:s0
/cache/overlay/(vendor|odm)/upper           u:object_r:vendor_file:s0
/cache/overlay/oem/upper                    u:object_r:vendor_file:s0
 

 平台上下文中间文件：

ls out/target/product/rk3399_roc_pc_plus/obj/ETC/plat_

plat_file_contexts_intermediates/               plat_pub_versioned.cil_intermediates/

plat_file_contexts.recovery_intermediates/      plat_seapp_contexts_intermediates/

plat_hwservice_contexts_intermediates/          plat_seapp_neverallows_intermediates/

plat_mac_permissions.xml_intermediates/         plat_sepolicy_and_mapping.sha256_intermediates/

plat_mapping_file_intermediates/                plat_sepolicy.cil_intermediates/

plat_property_contexts_intermediates/           plat_sepolicy_vers.txt_intermediates/

plat_property_contexts.recovery_intermediates/  plat_service_contexts_intermediates/

厂商上下文中间文件：

ls out/target/product/rk3399_roc_pc_plus/obj/ETC/vendor_

vendor_file_contexts_intermediates/              vendor_property_contexts_intermediates/

vendor_file_contexts.recovery_intermediates/     vendor_property_contexts.recovery_intermediates/

vendor_hwservice_contexts_intermediates/         vendor_seapp_contexts_intermediates/

vendor_mac_permissions.xml_intermediates/        vendor_sepolicy.cil_intermediates/

 生成的中间policy.conf文件：

find ./out/target/product/rk3399_roc_pc_plus/obj/ETC/ -name "*policy.conf"
./out/target/product/rk3399_roc_pc_plus/obj/ETC/treble_sepolicy_tests_26.0_intermediates/26.0_plat_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/general_sepolicy.conf_intermediates/general_sepolicy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/treble_sepolicy_tests_28.0_intermediates/28.0_plat_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/vendor_sepolicy.cil_intermediates/vendor_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/treble_sepolicy_tests_27.0_intermediates/27.0_plat_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/plat_sepolicy.cil_intermediates/plat_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/userdebug_plat_sepolicy.cil_intermediates/userdebug_plat_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/built_plat_sepolicy_intermediates/base_plat_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/built_plat_sepolicy_intermediates/base_plat_pub_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/sepolicy_neverallows_intermediates/plat_pub_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/sepolicy_neverallows_intermediates/pub_policy.conf
./out/target/product/rk3399_roc_pc_plus/obj/ETC/sepolicy_neverallows_intermediates/policy.conf

四， 编译出来的目标文件

平台分区安全策略目标文件

ls out/target/product/rk3399_roc_pc_plus/system/etc/selinux/

mapping   #用于向后兼容的映射文件，源码也是cil类型， 最终会被用于动态编译                

plat_mac_permissions.xml  

plat_sepolicy_and_mapping.sha256

plat_file_contexts       

plat_property_contexts    

plat_sepolicy.cil #平台私有和公共的所有策略文件， 最终会被用于动态编译

plat_hwservice_contexts  

plat_seapp_contexts       

plat_service_contexts

Vendor分区安全策略目标文件：

 ls out/target/product/rk3399_roc_pc_plus/product/etc/selinux/

plat_pub_versioned.cil    #平台公共的type和attribut映射到vendor版本的类型和属性如typeattribute dev_type

      # typeattributeset dev_type (device_29_0 audio_device_29_0 ...)

vendor_hwservice_contexts   

vendor_sepolicy.cil     #vendor的公共和私有的所有策略文爱九年， 最终会被用于动态编译

plat_sepolicy_vers.txt   #用于指示当前vendor 策略文件的版本

vendor_mac_permissions.xml  

vndservice_contexts

selinux_denial_metadata  

vendor_property_contexts

vendor_file_contexts     

vendor_seapp_contexts

odm分区安全策略目标文件：

ls out/target/product/rk3399_roc_pc_plus/odm/etc/selinux/

precompiled_sepolicy   //最终的二进制文件-会写入到内核中

precompiled_sepolicy.plat_sepolicy_and_mapping.sha256

precompiled_sepolicy.product_sepolicy_and_mapping.sha256