JIYIK CN >

The remote host uses the Linux system.

The first step is definitely to establish a code synchronization mechanism on the local and remote hosts - sftp is the first choice.

The second step is to write the CMakeLists.txt file of redis4. There is a complete CMakeLists.txt file in the Mac system clion debugging redis4 source code . You can use it, so I won’t write it here.

The third step is to build the project on the remote host and compile it with make, and then usegdbserver :port src/redis-server

The last step is to create a new one in clion gdb remote debug, which is also introduced in other notes, so I won’t go into details here.

The main thing that needs to be explained is the third step. Various problems will arise during building and compiling.

1. cmake version, because we specified the minimum version of cmake required in CMakeLists.txt. By default, the cmake version in the Linux remote host may be lower, so you need to upgrade the cmake version.
2. After the cmake project is built, the following error occurs when using make to compile

$ make
......
/root/workspace/c/redis4/src/redis-cli.c:368:5: 错误：只允许在 C99 模式下使用‘for’循环初始化声明
     for (size_t j = 0; j < reply->elements; j++) {
     ^
/root/workspace/c/redis4/src/redis-cli.c:368:5: 附注：使用 -std=c99 或 -std=gnu99 来编译您的代码
/root/workspace/c/redis4/src/redis-cli.c: 在函数‘LRUTestMode’中:
/root/workspace/c/redis4/src/redis-cli.c:2729:17: 错误：只允许在 C99 模式下使用‘for’循环初始化声明
                 for (int i = 0; i < 5; i++) val[i] = 'A'+rand()%('z'-'A');
                 ^
make[2]: *** [CMakeFiles/redis-cli.dir/src/redis-cli.c.o] 错误 1
make[1]: *** [CMakeFiles/redis-cli.dir/all] 错误 2
make: *** [all] 错误 2

The reason for this is that the default C standard in Linux does not allow forvariables to be declared directly in a loop. C99/gnu99It is only allowed in the standard. So you need to specify C99the standard.

Modify redis4/CMakeLists.txtthe file to the following content

cmake_minimum_required(VERSION 3.15)
project(redis4_1)
set(CMAKE_BUILD_TYPE "Debug")
set(CMAKE_C_FLAGS "-std=c99")  ### 新增
......

Add a new line of code, and keep the rest unchanged.

$ make
[ 93%] Building C object CMakeFiles/redis-server.dir/src/sparkline.c.o
[ 94%] Linking C executable src/redis-server
CMakeFiles/redis-server.dir/src/module.c.o：在函数‘moduleLoad’中：
/root/workspace/c/redis4/src/module.c:3935：对‘dlopen’未定义的引用
/root/workspace/c/redis4/src/module.c:3937：对‘dlerror’未定义的引用
/root/workspace/c/redis4/src/module.c:3940：对‘dlsym’未定义的引用
/root/workspace/c/redis4/src/module.c:3952：对‘dlclose’未定义的引用
CMakeFiles/redis-server.dir/src/module.c.o：在函数‘moduleUnload’中：
/root/workspace/c/redis4/src/module.c:3994：对‘dlclose’未定义的引用
/root/workspace/c/redis4/src/module.c:3995：对‘dlerror’未定义的引用
CMakeFiles/redis-server.dir/src/debug.c.o：在函数‘dumpX86Calls’中：
/root/workspace/c/redis4/src/debug.c:1011：对‘dladdr’未定义的引用
CMakeFiles/redis-server.dir/src/debug.c.o：在函数‘sigsegvHandler’中：
/root/workspace/c/redis4/src/debug.c:1078：对‘dladdr’未定义的引用
collect2: 错误：ld 返回 1
make[2]: *** [src/redis-server] 错误 1
make[1]: *** [CMakeFiles/redis-server.dir/all] 错误 2
make: *** [all] 错误 2

It is found that the for loop problem is solved, but a new problem arises. For this dlxxxx 函数未定义的引用problem, you need to specify it when compiling.-ldl

How to achieve it also requires changing redis4/CMakeLists.txtthe file.

......
add_executable(redis-server ${SRC_SERVER})
target_include_directories(redis-server
        PRIVATE ${REDIS_ROOT}/deps/linenoise
        PRIVATE ${REDIS_ROOT}/deps/hiredis
        PRIVATE ${REDIS_ROOT}/deps/lua/src)
target_link_libraries(redis-server
        PRIVATE pthread
        PRIVATE m
        PRIVATE lua
        PRIVATE linenoise
        PRIVATE hiredis
        -ldl)  ### 新增 -ldl 选项

The rest of the file remains unchanged.

$ rm -f CMakeCache.txt
$ cmake .
$ make
...
[ 97%] Linking C shared library helloblock.so
[ 97%] Built target helloblock
[ 98%] Building C object src/modules/CMakeFiles/hellotype.dir/hellotype.c.o
[ 99%] Linking C shared library hellotype.so
[ 99%] Built target hellotype
[ 99%] Building C object src/modules/CMakeFiles/helloworld.dir/helloworld.c.o
[100%] Linking C shared library helloworld.so
[100%] Built target helloworld

Very good, it worked.

Have fun with debugging!