94 lines
8.8 KiB
Markdown
94 lines
8.8 KiB
Markdown
# SysABI
|
|
|
|
Syscalls are a way for programms to communicate with the kernel.
|
|
|
|
To perform a syscall, you need to populate the following registers:
|
|
|
|
| Register | Value |
|
|
|----------|-----------------|
|
|
| rax | The syscalls ID |
|
|
| rdi | Argument 1 |
|
|
| rsi | Argument 2 |
|
|
| rdx | Argument 3 |
|
|
| rcx | Argument 4 |
|
|
|
|
---
|
|
|
|
The following calls should be implemented to some degree in noxos 1.0.
|
|
|
|
# Categories
|
|
## Files
|
|
| ID | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status |
|
|
|--------|----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------|--------|------|-------------|--------|-------------|
|
|
| 0x0001 | `nx_fs_open` | Opens the file at the _len_ bytes long path _path_ and writes a file descriptor to the referenced file into _fd_ (which needs to be a pointer). | path | len | *fd | | status | Implemented |
|
|
| 0x0002 | `nx_fs_close` | Closes the file which is indicated by descriptor _fd_. This should always be called, otherwise the OS will have to unload files without knowledge of usage. | fd | | | | status | Implemented |
|
|
| 0x0003 | `nx_fs_read` | Reads at most _n_ bytes from a file given as descriptor _fd_ and at a specific position _offset_ into a given memory region _mem_. | fd | offset | mem | n | status | Implemented |
|
|
| 0x0004 | `nx_fs_write` | Writes _n_ bytes from a given memory region _mem_ into the file referenced by _fd_ at the given position _offset_, not inserting but either overwriting existing content or appending to the file. | fd | offset | mem | n | status | Implemented |
|
|
| 0x0005 | `nx_fs_delete` | Completely delete the file or folder at a given path _path_, which is _len_ bytes long. | path | len | | | status | Implemented |
|
|
| 0x0006 | `nx_fs_list` | List all files and/or directories at the _len_ bytes long path _path_ and write their NULL-separated names into _mem_. When _mem_ is NULL, _needed_mem_ (which needs to be a pointer to an 32-bit integer) is filled with the appropriate value. | path | len | mem | *needed_mem | status | Implemented |
|
|
| 0x0007 | `nx_fs_info` | Writes the information about the files attribute _attr_ into mem. Types of attributes are described below. | fd | attr | mem | | status | N/A |
|
|
|
|
**Note:** The _len_ argument of paths isn't used at the moment, rather than using _len_, _path_ needs to be Null-Terminated.
|
|
|
|
## Memory
|
|
| ID | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status |
|
|
|--------|------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|------|------|-------|------|--------|-------------|
|
|
| 0x0101 | `nx_mem_alloc` | Maps _n_ 4KB pages to address _addr_. You can provide a bitmap of flags with the _flags_ argument. Which flags can be used, is described below. | addr | n | flags | | status | Implemented |
|
|
| 0x0102 | `nx_mem_free` | Unmaps _n_ 4KB pages at address _addr_. | addr | n | | | status | Implemented |
|
|
| 0x0103 | `nx_mem_label` | Gives a memory region a file descriptor, called a label, which can then be used for example for executing executable data in that memory region in a new process | addr | len | *fd | | status | N/A |
|
|
| 0x0104 | `nx_mem_unlabel` | Takes the file descriptor away from a memory region. | fd | | | | status | N/A |
|
|
|
|
## Processes
|
|
| ID | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status |
|
|
|--------|------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------|------|--------|----------|------|--------|--------|
|
|
| 0x0201 | `nx_proc_create` | Creates a new process with the configuration _conf_ (which format is described below) and writes its process id to _pid_. | conf | *pid | | | status | N/A |
|
|
| 0x0202 | `nx_proc_signal_send` | Send the signal _signal_ to _pid_. See below for a list of signals. | pid | signal | | | status | N/A |
|
|
| 0x0203 | `nx_proc_signal_set_handler` | Sets a handler for the signal _signal_ in the process _pid_. Not all signals can have a handler. Look at the list for more information. | pid | signal | *handler | | status | N/A |
|
|
| 0x0204 | `nx_proc_thread_create` | Spawns a new thread for the current process. The starting point is defined by _addr_. The threads' ID is written into _tid_. | addr | *tid | | | status | N/A |
|
|
| 0x0205 | `nx_proc_thread_start` | Starts the current processes' thread with thread id _tid_. | tid | | | | status | N/A |
|
|
| 0x0206 | `nx_proc_thread_pause` | Pauses the current processes' thread with thread id _tid_. | tid | | | | status | N/A |
|
|
| 0x0207 | `nx_proc_thread_kill` | Kills the current processes' thread with thread id _tid_. | tid | | | | status | N/A |
|
|
|
|
## Drivers
|
|
| ID | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status |
|
|
|-----|------|-------------|------|------|------|------|--------|--------|
|
|
| | | | | | | | | |
|
|
|
|
## Kernel
|
|
The kernel syscalls can only be called from the kernels main process [link to processing article needed].
|
|
If another process calls them, they will just return without doing anything.
|
|
|
|
|
|
| ID | Name | Description | Arg1 | Arg2 | Arg3 | Arg4 | Result | Status |
|
|
|-----|------|-------------|------|------|------|------|--------|--------|
|
|
| | | | | | | | | |
|
|
|
|
---
|
|
|
|
## Appendixes
|
|
|
|
### Types of file attributes
|
|
|
|
| ID | Name | Description | Data Type | Status |
|
|
|-----|---------------|--------------------------------------------|-----------|--------|
|
|
| 0 | `permissions` | Who has what permission to access the file | uint16_t | N/A |
|
|
| 1 | `size` | The files size in bytes | uint64_t | N/A |
|
|
|
|
|
|
### Memory mapping flags
|
|
|
|
| Bit | Name | Description |
|
|
|-----|-----------|-------------------------------------------|
|
|
| 0 | `write` | Enables write access to the mapped pages. |
|
|
| 1 | `no_exec` | Prevents execution of the mapped pages. |
|
|
|
|
### Process configuration
|
|
|
|
### Process signals
|
|
- __SIGSTART__: starts the process
|
|
- __SIGPAUSE__: pauses the process
|
|
- __SIGKILL__: kills the process and destroys the processes data structures
|
|
- __SIGEXIT__: send by the kernel before stopping the process - handler implementation possible
|
|
- __SIGPFAULT__: sends when the process access memory it is not permitted to. Followed by SIGEXIT - handler implementation possible
|
|
- __SIGMATHAULT__: sends when the process does stuff like dividing by zero. Followed by SIGEXIT - handler implementation possible
|