Building the C. execvp shell returns an "No such file" error. create argv array on the fly with malloc

I create a shell and am having problems with the execvp system call. I saw some other questions on this topic, but they were vague and did not seem to be completely resolved (whoever asked questions, did not provide a lot of information and did not receive good answers).

Obviously, I have my own command line, and I am reading user input from stdin, like

mysh some/path $ ps -a 

and I create an args array as char **, and the array itself works (I think), because when I print the values ​​inside my function, it shows

args[0] = 'ps'
args[1] = '-a'
args[2] = '(null)'

So, I call fork and execvp (cmnd, args) in my process where cmnd is “ps” and args is as above, and perror etc.

I get

'Error: no such file or directory.'  

$PATH? - ?

args:

char ** get_args(char * cmnd) {
int index = 0;
char **args = (char **)emalloc(sizeof(char *));
char * copy = (char *) emalloc(sizeof(char)*(strlen(cmnd)));
strncpy(copy,cmnd,strlen(cmnd));
char * tok = strtok(copy," ");
while(tok != NULL) {
    args[index] = (char *) emalloc(sizeof(char)*(strlen(tok)+1));
    strncpy(args[index],tok,strlen(tok)+1);
    index++;
    tok = strtok(NULL," ");
    args = (char**) erealloc(args,sizeof(char*)*(index+1));
}
args[index] = NULL;
return args;
}

(emalloc erealloc - malloc realloc )

, :

void exec_cmnd(char*cmnd, char**args) {
pid_t pid;
if((pid=fork())==0) {
    execvp(cmnd, args);
    perror("Error");
    free(args);
    free(cmnd);
    exit(1);
}
else {
    int ReturnCode;
    while(pid!=wait(&ReturnCode)) {
        ;
    }
}
}

, , execvp , , - , (.. argv == {'ps', NULL})

, . .