Android: 启动init.rc 中service的权限问题【转】

转自：/Linux/-04/35014.htm

通过property_set("ctl.start", service_xx);

来启动init.rc中的service是一个很方便方法来调用某个可执行程序或某个脚本程序

service service_xx /system/bin/xx

disabled

oneshot

但在非AID_ROOT、AID_SYSTEM 用户的进程中调用ctl.start ctl.stop会碰到权限问题:

system/core/init/property_service.c

/*

* White list of UID that are allowed to start/stop services.

* Currently there are no user apps that require.

*/

struct {

const char *service;

unsigned int uid;

unsigned int gid;

} control_perms[] = {

{ "dumpstate",AID_SHELL, AID_LOG },

{NULL, 0, 0 }

};

/*

* Checks permissions for starting/stoping system services.

* AID_SYSTEM and AID_ROOT are always allowed.

*

* Returns 1 if uid allowed, 0 otherwise.

*/

static int check_control_perms(const char *name, int uid, int gid) {

int i;

if (uid == AID_SYSTEM || uid == AID_ROOT)

return 1;

/* Search the ACL */

for (i = 0; control_perms[i].service; i++) {

if (strcmp(control_perms[i].service, name) == 0) {

if ((uid && control_perms[i].uid == uid) ||

(gid && control_perms[i].gid == gid)) {

return 1;

}

}

}

return 0;

}

本文来自CSDN博客，转载请标明出处：/zmyde/archive//04/09/6312615.aspx

只有uid == AID_SYSTEM || uid == AID_ROOT

或符合 control_perms[] = {

{ "dumpstate",AID_SHELL, AID_LOG },

{NULL, 0, 0 }

}; 的uid进程才有权限star/stop services

因此，如果我们碰到了权限问题，根据log提示，在/system/core/include/private/Android_filesystem_config.h

中查到进程定义，添加到control_perms[]列表

比如，uid ==AID_WIFI的某个程序需要权限启动service_xx

control_perms[] = {

{ "dumpstate",AID_SHELL, AID_LOG },

+ { "service_xx ",AID_WIFI, AID_WIFI},

{NULL, 0, 0 }

};

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