Hotfix/sangshuduo/td 3197 taosdemo coverity scan for master (#7510)

* [TD-3197]<fix>: taosdemo and taosdump coverity scan issues.

* exit if read sample file failed.

* fix converity scan issue.

* fix coverity scan issue.

* fix coverity scan memory leak.

* fix resource leak reported by coverity scan.

* fix taosdemo coverity scan issue.

* fix tcsetattr and getchar return value determination bug.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

src/kit/shell/src/shellLinux.c

@@ -177,7 +177,9 @@ static void parse_args(
                     fprintf(stderr, "password reading error\n");
                 }
                 taosSetConsoleEcho(true);
-                getchar();
+                if (EOF == getchar()) {
+                    fprintf(stderr, "getchar() return EOF\n");
+                }
             } else {
                 tstrncpy(g_password, (char *)(argv[i] + 2), SHELL_MAX_PASSWORD_LEN);
                 strcpy(argv[i], "-p");

src/os/src/linux/osSystem.c

@@ -63,12 +63,12 @@ int taosSetConsoleEcho(bool on)
     }
 
     if (on)
-        term.c_lflag|=ECHOFLAGS;
+        term.c_lflag |= ECHOFLAGS;
     else
-        term.c_lflag &=~ECHOFLAGS;
+        term.c_lflag &= ~ECHOFLAGS;
 
-    err = tcsetattr(STDIN_FILENO,TCSAFLUSH,&term);
-    if (err == -1 && err == EINTR) {
+    err = tcsetattr(STDIN_FILENO, TCSAFLUSH, &term);
+    if (err == -1 || err == EINTR) {
         perror("Cannot set the attribution of the terminal");
         return -1;
     }