Function _msh_exec_search_env

components/finsh/msh.c:428–478

* search for the file named "pg_name" or "pg_name.elf" at each env path, * and return its path. return NULL when not found. */

 * and return its path. return NULL when not found.
 */
static char *_msh_exec_search_env(const char *pg_name)
{
    char *result = RT_NULL;
    char *exec_path = RT_NULL;
    char *search_path = RT_NULL;
    char *pos = RT_NULL;
    char tmp_ch = '\0';

    if (!(exec_path = getenv("PATH")))
    {
        return RT_NULL;
    }

    /* exec path may need to be modified */
    if (!(exec_path = strdup(exec_path)))
    {
        return RT_NULL;
    }

    pos = exec_path;
    search_path = exec_path;

    /* walk through the entire exec_path until finding the program wanted
       or hitting its end */
    while (1)
    {
        /* env paths are seperated by ':' */
        if (*pos == ':' || *pos == '\0')
        {
            tmp_ch = *pos;
            *pos = '\0';

            result = _msh_exec_search_path(search_path, pg_name);
            if (result || tmp_ch == '\0')
            {
                goto ret;
            }

            pos++;
            search_path = pos;
            continue;
        }

        pos++;
    }

    /* release the duplicated exec_path and return */
ret:
    rt_free(exec_path);
    return result;
}

int _msh_exec_lwp(int debug, char *cmd, rt_size_t length)
{