functions
| Prompt allowed functions | Definition |
|---|---|
| readline | readline will read a line from the terminal and return it, using prompt as a prompt. |
| rl_clear_history | Clear the history list by deleting all of the entries |
| rl_on_new_line | Tell the update functions that we have moved onto a new (empty) line, usually after outputting a newline. |
| rl_replace_line | Replace the contents of rl_line_buffer with text |
| rl_redisplay | Change what's displayed on the screen to reflect the current contents of rl_line_buffer. |
| add_history | Place string at the end of the history list |
| getenv | searches the environment list to find the environment variable name, and returns a pointer to the corresponding value string |
| System Call allowed functions | Definition |
|---|---|
| pipe |  |
| fork |  |
| wait |  |
| waitpid | The waitpid() system call suspends execution of the calling process until a child specified by pid argument has changed state |
| sigaction | change the action taken by a process on receipt of a specific signal |
| kill | send signal to a process |
| ioctl | ioctl is a system call for device-specific input/output operations and other operations which cannot be expressed by regular system calls. |
| execve | executes the program referred to by pathname |
| fd allowed functions | Definition |
|---|---|
| access | checks whether the calling process can access the file pathname |
| stat | get file status |
| unlink | deletes a name from the file system |
| dup/dup2 | duplicates a file descriptor |
| isatty | tests whether fd is an open file descriptor referring to a terminal |
| ttyname | returns a pointer to the null-terminated pathname of the terminal device that is open on the file descriptor fd |
| ttyslot | find the slot of the current user's terminal in some file |
| dir allowed functions | Definition |
|---|---|
| getcwd | get current working directory |
| chdir | change working directory |
| open/read/close -dir | opens, read and closes a directory stream corresponding to the directory name |
| error allowed functions | Definition |
|---|---|
| strerror | returns a pointer to a string that describes the error code passed in the argument errnum |
| perror | prints a descriptive error message to stderr |