Build TLS as a loadable module

* Support BUILD_TLS=module to be loaded as a module via config file or
  command line. e.g. redis-server --loadmodule redis-tls.so
* Updates to redismodule.h to allow it to be used side by side with
  server.h by defining REDISMODULE_CORE_MODULE
* Changes to server.h, redismodule.h and module.c to avoid repeated
  type declarations (gcc 4.8 doesn't like these)
* Add a mechanism for non-ABI neutral modules (ones who include
  server.h) to refuse loading if they detect not being built together with
  redis (release.c)
* Fix wrong signature of RedisModuleDefragFunc, this could break
  compilation of a module, but not the ABI
* Move initialization of listeners in server.c to be after loading
  the modules
* Config TLS after initialization of listeners
* Init cluster after initialization of listeners
* Add TLS module to CI
* Fix a test suite race conditions:
  Now that the listeners are initialized later, it's not sufficient to
  wait for the PID message in the log, we need to wait for the "Server
  Initialized" message.
* Fix issues with moduleconfigs test as a result from start_server
  waiting for "Server Initialized"
* Fix issues with modules/infra test as a result of an additional module
  present

Notes about Sentinel:
Sentinel can't really rely on the tls module, since it uses hiredis to
initiate connections and depends on OpenSSL (won't be able to use any
other connection modules for that), so it was decided that when TLS is
built as a module, sentinel does not support TLS at all.
This means that it keeps using redis_tls_ctx and redis_tls_client_ctx directly.

Example code of config in redis-tls.so(may be use in the future):
RedisModuleString *tls_cfg = NULL;

void tlsInfo(RedisModuleInfoCtx *ctx, int for_crash_report) {
    UNUSED(for_crash_report);
    RedisModule_InfoAddSection(ctx, "");
    RedisModule_InfoAddFieldLongLong(ctx, "var", 42);
}

int tlsCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
    if (argc != 2) return RedisModule_WrongArity(ctx);
    return RedisModule_ReplyWithString(ctx, argv[1]);
}

RedisModuleString *getStringConfigCommand(const char *name, void *privdata) {
    REDISMODULE_NOT_USED(name);
    REDISMODULE_NOT_USED(privdata);
    return tls_cfg;
}

int setStringConfigCommand(const char *name, RedisModuleString *new, void *privdata, RedisModuleString **err) {
    REDISMODULE_NOT_USED(name);
    REDISMODULE_NOT_USED(err);
    REDISMODULE_NOT_USED(privdata);
    if (tls_cfg) RedisModule_FreeString(NULL, tls_cfg);
    RedisModule_RetainString(NULL, new);
    tls_cfg = new;
    return REDISMODULE_OK;
}

int RedisModule_OnLoad(void *ctx, RedisModuleString **argv, int argc)
{
    ....
    if (RedisModule_CreateCommand(ctx,"tls",tlsCommand,"",0,0,0) == REDISMODULE_ERR)
        return REDISMODULE_ERR;

    if (RedisModule_RegisterStringConfig(ctx, "cfg", "", REDISMODULE_CONFIG_DEFAULT, getStringConfigCommand, setStringConfigCommand, NULL, NULL) == REDISMODULE_ERR)
        return REDISMODULE_ERR;

    if (RedisModule_LoadConfigs(ctx) == REDISMODULE_ERR) {
        if (tls_cfg) {
            RedisModule_FreeString(ctx, tls_cfg);
            tls_cfg = NULL;
        }
        return REDISMODULE_ERR;
    }
    ...
}

Co-authored-by: zhenwei pi <pizhenwei@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>

2 files changed, 8 insertions, 7 deletions

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2b406f74b..f6a61b0e0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,7 +24,8 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: make
-        run: make SANITIZER=address REDIS_CFLAGS='-Werror'
+        # build with TLS module just for compilation coverage
+        run: make SANITIZER=address REDIS_CFLAGS='-Werror' BUILD_TLS=module
       - name: testprep
         run: sudo apt-get install tcl8.6 tclx -y
       - name: test
diff --git a/.github/workflows/daily.yml b/.github/workflows/daily.yml
index da3c8a21f..e9e0549af 100644
--- a/.github/workflows/daily.yml
+++ b/.github/workflows/daily.yml
@@ -539,7 +539,7 @@ jobs:
       run: |
         yum -y install centos-release-scl epel-release
         yum -y install devtoolset-7 openssl-devel openssl
-        scl enable devtoolset-7 "make BUILD_TLS=yes REDIS_CFLAGS='-Werror'"
+        scl enable devtoolset-7 "make BUILD_TLS=module REDIS_CFLAGS='-Werror'"
     - name: testprep
       run: |
         yum -y install tcl tcltls tclx
@@ -547,19 +547,19 @@ jobs:
     - name: test
       if: true && !contains(github.event.inputs.skiptests, 'redis')
       run: |
-        ./runtest --accurate --verbose --dump-logs --tls --dump-logs ${{github.event.inputs.test_args}}
+        ./runtest --accurate --verbose --dump-logs --tls-module --dump-logs ${{github.event.inputs.test_args}}
     - name: module api test
       if: true && !contains(github.event.inputs.skiptests, 'modules')
       run: |
-        ./runtest-moduleapi --verbose --dump-logs --tls --dump-logs ${{github.event.inputs.test_args}}
+        ./runtest-moduleapi --verbose --dump-logs --tls-module --dump-logs ${{github.event.inputs.test_args}}
     - name: sentinel tests
       if: true && !contains(github.event.inputs.skiptests, 'sentinel')
       run: |
-        ./runtest-sentinel --tls ${{github.event.inputs.cluster_test_args}}
+        ./runtest-sentinel ${{github.event.inputs.cluster_test_args}}
     - name: cluster tests
       if: true && !contains(github.event.inputs.skiptests, 'cluster')
       run: |
-        ./runtest-cluster --tls ${{github.event.inputs.cluster_test_args}}
+        ./runtest-cluster --tls-module ${{github.event.inputs.cluster_test_args}}
 
   test-centos7-tls-no-tls:
     runs-on: ubuntu-latest
@@ -582,7 +582,7 @@ jobs:
       run: |
         yum -y install centos-release-scl epel-release
         yum -y install devtoolset-7 openssl-devel openssl
-        scl enable devtoolset-7 "make BUILD_TLS=yes REDIS_CFLAGS='-Werror'"
+        scl enable devtoolset-7 "make BUILD_TLS=module REDIS_CFLAGS='-Werror'"
     - name: testprep
       run: |
         yum -y install tcl tcltls tclx