libvideorender: CB1 fix crash on executeCmd [1/1]

PD#TV-111307

Problem:
when DTV changes channel fast, sometimes
popen return null, it causes fget crash with null point

Solution:
invoking fget after popen success

Verify:
AH212

Change-Id: I56fac937c337c5666f3f02982ab25f28f7d39ad8
Signed-off-by: fei.deng <fei.deng@amlogic.com>
diff --git a/westeros/wstclient_wayland.cpp b/westeros/wstclient_wayland.cpp
index 5ffd3d2..d77f6c5 100644
--- a/westeros/wstclient_wayland.cpp
+++ b/westeros/wstclient_wayland.cpp
@@ -446,6 +446,8 @@
             ERROR(mLogCategory, "wayland connect rlib-display fail");
             return ERROR_OPEN_FAIL;
         }
+        setenv("XDG_RUNTIME_DIR",xdgEnv,0);
+        setenv("WAYLAND_DISPLAY",displayName,0);
         INFO(mLogCategory,"wayland connected to rlib-display");
     }
 
@@ -1065,8 +1067,10 @@
 void WstClientWayland::executeCmd(const char *cmd) {
     INFO(mLogCategory,"%s", cmd);
     FILE* pFile = popen(cmd, "r");
-    char buf[128];
-    char* retStr = fgets(buf, sizeof(buf), pFile);
-    INFO(mLogCategory,"ret= %s", retStr);
-    pclose(pFile);
+    if (pFile) {
+        char buf[128];
+        char* retStr = fgets(buf, sizeof(buf), pFile);
+        INFO(mLogCategory,"ret= %s", retStr);
+        pclose(pFile);
+    }
 }
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