uclibc编译
当海思自带的uclibc库无法满足要求时，可以通过uclibc源码编译出满足要求的libc版本。如海思自带的uclibc库不支持LD_PRELOAD选项时，可以通过编译uclibc源码使其支持LD_PRELOAD选项。
查看现有版本
编译的uclibc版本最好和当前系统的libc版本匹配，这样移植后续应用程序也比较方便，可以通过如下命令查看当前板子上的uclibc版本，我的板子上uclibc版本是0.9.33.2。
/nfs/h18e3 # ls /lib/ld*
/lib/ld-uClibc-0.9.33.2.so /lib/ld-uClibc.so.0
下载源码
从如下地址下载对应版本的uclibc：
https://uclibc.org/downloads/
编译选项
首先解压下载的uclibc源码压缩包：
tar xf uClibc-0.9.33.2.tar.bz2
cd uClibc-0.9.33.2/
make menuconfig
其次设置对应的交叉编译器与编译选项：
- 将"Target Architecture"设置为"arm"。
- 设置"Target Architecture Features and Options"中的"Target Processor Endianness"为"Little Endian"。
- 设置"Target Architecture Features and Options"中的"Linux kernel header location"为： “/opt/hisi-linux/x86-arm/arm-himix100-linux/target/usr/include/”（注：需要依据海思交叉编译器的安装目录自行设置）。
- 设置"Development/debugging options"中的"Cros-compiling toolchain prefix"为"arm-himix100-linux-"。
- 设置"Development/debugging options"中的"Extra CFLAGS"为"-mcpu=cortex-a7 -mfloat-abi=softfp -mfpu=neon-vfpv4 -fno-aggressive-loop-optimizations"。
- 依照项目的需求自行打开/关闭其他相关编译选项，如：
- “Target Architecture Features and Options"中的"Enable full C99 math library support”，打开log()等数学函数库支持。
- “General Library Settings"中的"Enable library loader LD_PRELOAD environment”，开启LD_PRELOAD支持。
- “General Library Settings"中的"Enable SuSv3 LEGACY macros”，否则 usleep()函数无法使用。
- “String and Stdio Support"中的"Wide Character Support”，打开wchar支持。
- 在调试阶段，打开尽可能多的选项。
make选项设置完毕，使用如下命令编译，并查看生成的so文件：
[cxm@cxm-desktop uClibc-0.9.33.2]$ make -j
[cxm@cxm-desktop uClibc-0.9.33.2]$ ls ./lib/*so*
./lib/ld-uClibc-0.9.33.2.so ./lib/libcrypt.so.0 ./lib/libm-0.9.33.2.so ./lib/libpthread-0.9.33.2.so ./lib/libresolv.so.0 ./lib/libutil.so
./lib/ld-uClibc.so ./lib/libc.so ./lib/libm.so ./lib/libpthread.so ./lib/librt-0.9.33.2.so ./lib/libutil.so.0
./lib/ld-uClibc.so.0 ./lib/libc.so.0 ./lib/libm.so.0 ./lib/libpthread.so.0 ./lib/librt.so
./lib/ld-uClibc.so.lds ./lib/libdl-0.9.33.2.so ./lib/libnsl-0.9.33.2.so ./lib/libresolv-0.9.33.2.so ./lib/librt.so.0
./lib/libcrypt-0.9.33.2.so ./lib/libdl.so ./lib/libnsl.so ./lib/libresolv.a ./lib/libuClibc-0.9.33.2.so
./lib/libcrypt.so ./lib/libdl.so.0 ./lib/libnsl.so.0 ./lib/libresolv.so ./lib/libutil-0.9.33.2.so
编译应用程序
uclibc编译成功后，需要将生成的so文件拷贝到交叉编译器对应的目录，并重新编译你的应用程序。使用如下命令确认需要拷贝的目录：
[cxm@cxm-desktop uClibc-0.9.33.2]$ arm-himix100-linux-gcc -print-file-name=libdl.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/libdl.so
[cxm@cxm-desktop uClibc-0.9.33.2]$ file /opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/libdl.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/libdl.so: symbolic link to ../../lib/libdl.so.0
[cxm@cxm-desktop uClibc-0.9.33.2]$ ls /opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/*9.33.2*so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/ld-uClibc-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libcrypt-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libdl-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libm-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libnsl-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libpthread-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libresolv-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/librt-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libuClibc-0.9.33.2.so
/opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/libutil-0.9.33.2.so
[cxm@cxm-desktop uClibc-0.9.33.2]$ sudo mkdir -p /opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/bak
[cxm@cxm-desktop uClibc-0.9.33.2]$ sudo cp /opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/*9.33.2*so /opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/bak
[cxm@cxm-desktop uClibc-0.9.33.2]$ sudo cp ./lib/*9.33.2*so /opt/hisi-linux/x86-arm/arm-himix100-linux/host_bin/../target/usr/lib/../../lib/
将so拷贝到对应的目录后，需要重新链接应用程序，如果应用程序使用了c++，建议使用静态链接c++库，即在编译时添加选项：
arm-himix100-linux-g++ -static-libstdc++ ...
运行
将编译的所有so文件拷贝到开发板对应的目录，使用如下命令执行应用程序：
/nfs/h18e3 # ls *9.33.2*so
ld-uClibc-0.9.33.2.so libdl-0.9.33.2.so libnsl-0.9.33.2.so libresolv-0.9.33.2.so libuClibc-0.9.33.2.so
libcrypt-0.9.33.2.so libm-0.9.33.2.so libpthread-0.9.33.2.so librt-0.9.33.2.so libutil-0.9.33.2.so
/nfs/h18e3 # LD_PRELOAD=hook.so ./ld-uClibc-0.9.33.2.so --library-path ./ ./yourapp yourargs 2>&1 | tee log
