android property 使用限制

properties属性名称不能超过31个字符

properties属性值不能超过91个字符

整个系统properties共享内存大小128K

bionic\libc\include\sys\system_properties.h
PROP_NAME_MAX 31
PROP_VALUE_MAX = 91

bionic\libc\include\sys\_system_properties.h
#define PA_SIZE         (128 * 1024)    

bionic\libc\bionic\system_properties.c

map_prop_area_rw()

{

    pa = mmap(NULL, pa_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);

}