Feat: add param load filter hook

add filter hook when loading system parameter from .para files.
Signed-off-by: Nhandyohos <zhangxiaotian@huawei.com>
Change-Id: I6be57c0f58727de6276bd3f10ab3da955edd4702

#I6HRVR

interfaces/innerkits/init_module_engine/include/bootstage.h

@@ -29,6 +29,7 @@ enum INIT_BOOTSTAGE {
     INIT_GLOBAL_INIT       = 0,
     INIT_PRE_PARAM_SERVICE = 10,
     INIT_PRE_PARAM_LOAD    = 20,
+    INIT_PARAM_LOAD_FILTER = 25,
     INIT_PRE_CFG_LOAD      = 30,
     INIT_SERVICE_PARSE     = 35,
     INIT_POST_PERSIST_PARAM_LOAD   = 40,
@@ -61,6 +62,29 @@ __attribute__((always_inline)) inline int InitAddPreParamLoadHook(int prio, Ohos
     return HookMgrAdd(GetBootStageHookMgr(), INIT_PRE_PARAM_LOAD, prio, hook);
 }
 
+/**
+ * @brief Parameter load filter context
+ */
+typedef struct tagPARAM_LOAD_FILTER_CTX {
+    const char *name;    /* Parameter name */
+    const char *value;   /* Parameter value */
+    int ignored;         /* Ignore this parameter or not */
+} PARAM_LOAD_FILTER_CTX;
+
+/**
+ * @brief Parameter Load Hook function prototype
+ *
+ * @param hookInfo hook information
+ * @param filter filter information context
+ * @return return 0 if succeed; other values if failed.
+ */
+typedef int (*ParamLoadFilter)(const HOOK_INFO *hookInfo, PARAM_LOAD_FILTER_CTX *filter);
+
+__attribute__((always_inline)) inline int InitAddParamLoadFilterHook(int prio, ParamLoadFilter filter)
+{
+    return HookMgrAdd(GetBootStageHookMgr(), INIT_PARAM_LOAD_FILTER, prio, (OhosHook)filter);
+}
+
 __attribute__((always_inline)) inline int InitAddPreCfgLoadHook(int prio, OhosHook hook)
 {
     return HookMgrAdd(GetBootStageHookMgr(), INIT_PRE_CFG_LOAD, prio, hook);

services/modules/init_hook/init_hook.c

@@ -236,6 +236,7 @@ static int BootCompleteCmd(const HOOK_INFO *hookInfo, void *executionContext)
     // clear hook
     HookMgrDel(GetBootStageHookMgr(), INIT_GLOBAL_INIT, NULL);
     HookMgrDel(GetBootStageHookMgr(), INIT_PRE_PARAM_SERVICE, NULL);
+    HookMgrDel(GetBootStageHookMgr(), INIT_PARAM_LOAD_FILTER, NULL);
     HookMgrDel(GetBootStageHookMgr(), INIT_PRE_PARAM_LOAD, NULL);
     HookMgrDel(GetBootStageHookMgr(), INIT_PRE_CFG_LOAD, NULL);
     HookMgrDel(GetBootStageHookMgr(), INIT_SERVICE_PARSE, NULL);

services/param/linux/BUILD.gn

@@ -107,6 +107,7 @@ if (defined(ohos_lite)) {
     defines = [
       "_GNU_SOURCE",
       "PARAM_SUPPORT_REAL_CHECK",
+      "SUPPORT_PARAM_LOAD_HOOK",
     ]
 
     if (param_base_log) {

services/param/manager/param_server.c

@@ -17,6 +17,9 @@
 
 #include "param_manager.h"
 #include "param_trie.h"
+#ifdef SUPPORT_PARAM_LOAD_HOOK
+#include "init_module_engine.h"
+#endif
 
 /**
  * Loading system parameter from /proc/cmdline by the following rules:
@@ -206,6 +209,22 @@ static int LoadOneParam_(const uint32_t *context, const char *name, const char *
     if (ret != 0) {
         return 0;
     }
+
+#ifdef SUPPORT_PARAM_LOAD_HOOK
+    PARAM_LOAD_FILTER_CTX filter;
+
+    // Filter by hook
+    filter.name = name;
+    filter.value = value;
+    filter.ignored = 0;
+    HookMgrExecute(GetBootStageHookMgr(), INIT_PARAM_LOAD_FILTER, (void *)&filter, NULL);
+
+    if (filter.ignored) {
+        PARAM_LOGV("Default parameter [%s] [%s] ignored", name, value);
+        return 0;
+    }
+#endif
+
     PARAM_LOGV("Add default parameter [%s] [%s]", name, value);
     return WriteParam(name, value, NULL, mode & LOAD_PARAM_ONLY_ADD);
 }