Odin/core/os/os_linux.odin

package os

foreign import dl   "system:dl"
foreign import libc "system:c"

import "core:runtime"
import "core:strings"

OS :: "linux";

Handle    :: distinct i32;
File_Time :: distinct u64;
Errno     :: distinct i32;
Syscall   :: distinct int;

INVALID_HANDLE :: ~Handle(0);

ERROR_NONE:    	Errno : 0;
EPERM:         	Errno : 1;
ENOENT:        	Errno : 2;
ESRCH:         	Errno : 3;
EINTR:         	Errno : 4;
EIO:           	Errno : 5;
ENXIO:         	Errno : 6;
EBADF:         	Errno : 9;
EAGAIN:        	Errno : 11;
ENOMEM:        	Errno : 12;
EACCES:        	Errno : 13;
EFAULT:        	Errno : 14;
EEXIST:        	Errno : 17;
ENODEV:        	Errno : 19;
ENOTDIR:       	Errno : 20;
EISDIR:        	Errno : 21;
EINVAL:        	Errno : 22;
ENFILE:        	Errno : 23;
EMFILE:        	Errno : 24;
ETXTBSY:       	Errno : 26;
EFBIG:         	Errno : 27;
ENOSPC:        	Errno : 28;
ESPIPE:        	Errno : 29;
EROFS:         	Errno : 30;
EPIPE:         	Errno : 32;

EDEADLK: 		Errno :	35;	/* Resource deadlock would occur */
ENAMETOOLONG: 	Errno : 36;	/* File name too long */
ENOLCK: 		Errno : 37;	/* No record locks available */

ENOSYS: Errno : 38;	/* Invalid system call number */

ENOTEMPTY: 	Errno : 39;	/* Directory not empty */
ELOOP: 		Errno : 40;	/* Too many symbolic links encountered */
EWOULDBLOCK: Errno : EAGAIN;	/* Operation would block */
ENOMSG: 	Errno : 42;	/* No message of desired type */
EIDRM: 		Errno : 43;	/* Identifier removed */
ECHRNG: 	Errno : 44;	/* Channel number out of range */
EL2NSYNC: 	Errno : 45;	/* Level 2 not synchronized */
EL3HLT: 	Errno : 46;	/* Level 3 halted */
EL3RST: 	Errno : 47;	/* Level 3 reset */
ELNRNG: 	Errno : 48;	/* Link number out of range */
EUNATCH: 	Errno : 49;	/* Protocol driver not attached */
ENOCSI: 	Errno : 50;	/* No CSI structure available */
EL2HLT: 	Errno : 51;	/* Level 2 halted */
EBADE: 		Errno : 52;	/* Invalid exchange */
EBADR: 		Errno : 53;	/* Invalid request descriptor */
EXFULL: 	Errno : 54;	/* Exchange full */
ENOANO: 	Errno : 55;	/* No anode */
EBADRQC: 	Errno : 56;	/* Invalid request code */
EBADSLT: 	Errno : 57;	/* Invalid slot */
EDEADLOCK:  Errno : EDEADLK;
EBFONT: 	Errno : 59;	/* Bad font file format */
ENOSTR: 	Errno : 60;	/* Device not a stream */
ENODATA: 	Errno : 61;	/* No data available */
ETIME: 		Errno : 62;	/* Timer expired */
ENOSR: 		Errno : 63;	/* Out of streams resources */
ENONET: 	Errno : 64;	/* Machine is not on the network */
ENOPKG: 	Errno : 65;	/* Package not installed */
EREMOTE: 	Errno : 66;	/* Object is remote */
ENOLINK: 	Errno : 67;	/* Link has been severed */
EADV: 		Errno : 68;	/* Advertise error */
ESRMNT: 	Errno : 69;	/* Srmount error */
ECOMM: 		Errno : 70;	/* Communication error on send */
EPROTO: 	Errno : 71;	/* Protocol error */
EMULTIHOP: 	Errno : 72;	/* Multihop attempted */
EDOTDOT: 	Errno : 73;	/* RFS specific error */
EBADMSG: 	Errno : 74;	/* Not a data message */
EOVERFLOW: 	Errno : 75;	/* Value too large for defined data type */
ENOTUNIQ: 	Errno : 76;	/* Name not unique on network */
EBADFD: 	Errno : 77;	/* File descriptor in bad state */
EREMCHG: 	Errno : 78;	/* Remote address changed */
ELIBACC: 	Errno : 79;	/* Can not access a needed shared library */
ELIBBAD: 	Errno : 80;	/* Accessing a corrupted shared library */
ELIBSCN: 	Errno : 81;	/* .lib section in a.out corrupted */
ELIBMAX: 	Errno : 82;	/* Attempting to link in too many shared libraries */
ELIBEXEC: 	Errno : 83;	/* Cannot exec a shared library directly */
EILSEQ: 	Errno : 84;	/* Illegal byte sequence */
ERESTART: 	Errno : 85;	/* Interrupted system call should be restarted */
ESTRPIPE: 	Errno : 86;	/* Streams pipe error */
EUSERS: 	Errno : 87;	/* Too many users */
ENOTSOCK: 	Errno : 88;	/* Socket operation on non-socket */
EDESTADDRREQ: Errno : 89;	/* Destination address required */
EMSGSIZE: 	Errno : 90;	/* Message too long */
EPROTOTYPE: Errno : 91;	/* Protocol wrong type for socket */
ENOPROTOOPT: 	Errno : 92;	/* Protocol not available */
EPROTONOSUPPORT: Errno : 93;	/* Protocol not supported */
ESOCKTNOSUPPORT: Errno : 94;	/* Socket type not supported */
EOPNOTSUPP: 	Errno : 95;	/* Operation not supported on transport endpoint */
EPFNOSUPPORT: 	Errno : 96;	/* Protocol family not supported */
EAFNOSUPPORT: 	Errno : 97;	/* Address family not supported by protocol */
EADDRINUSE: 	Errno : 98;	/* Address already in use */
EADDRNOTAVAIL: 	Errno : 99;	/* Cannot assign requested address */
ENETDOWN: 		Errno : 100;	/* Network is down */
ENETUNREACH: 	Errno : 101;	/* Network is unreachable */
ENETRESET: 		Errno : 102;	/* Network dropped connection because of reset */
ECONNABORTED: 	Errno : 103;	/* Software caused connection abort */
ECONNRESET: 	Errno : 104;	/* Connection reset by peer */
ENOBUFS: 		Errno : 105;	/* No buffer space available */
EISCONN: 		Errno : 106;	/* Transport endpoint is already connected */
ENOTCONN: 		Errno : 107;	/* Transport endpoint is not connected */
ESHUTDOWN: 		Errno : 108;	/* Cannot send after transport endpoint shutdown */
ETOOMANYREFS: 	Errno : 109;	/* Too many references: cannot splice */
ETIMEDOUT: 		Errno : 110;	/* Connection timed out */
ECONNREFUSED: 	Errno : 111;	/* Connection refused */
EHOSTDOWN: 		Errno : 112;	/* Host is down */
EHOSTUNREACH: 	Errno : 113;	/* No route to host */
EALREADY: 		Errno : 114;	/* Operation already in progress */
EINPROGRESS: 	Errno : 115;	/* Operation now in progress */
ESTALE: 		Errno : 116;	/* Stale file handle */
EUCLEAN: 		Errno : 117;	/* Structure needs cleaning */
ENOTNAM: 		Errno : 118;	/* Not a XENIX named type file */
ENAVAIL: 		Errno : 119;	/* No XENIX semaphores available */
EISNAM: 		Errno : 120;	/* Is a named type file */
EREMOTEIO: 		Errno : 121;	/* Remote I/O error */
EDQUOT: 		Errno : 122;	/* Quota exceeded */

ENOMEDIUM: 		Errno : 123;	/* No medium found */
EMEDIUMTYPE: 	Errno : 124;	/* Wrong medium type */
ECANCELED: 		Errno : 125;	/* Operation Canceled */
ENOKEY: 		Errno : 126;	/* Required key not available */
EKEYEXPIRED: 	Errno : 127;	/* Key has expired */
EKEYREVOKED: 	Errno : 128;	/* Key has been revoked */
EKEYREJECTED: 	Errno : 129;	/* Key was rejected by service */

/* for robust mutexes */
EOWNERDEAD: 	Errno : 130;	/* Owner died */
ENOTRECOVERABLE: Errno : 131;	/* State not recoverable */

ERFKILL: 		Errno : 132;	/* Operation not possible due to RF-kill */

EHWPOISON: 		Errno : 133;	/* Memory page has hardware error */

O_RDONLY   :: 0x00000;
O_WRONLY   :: 0x00001;
O_RDWR     :: 0x00002;
O_CREATE   :: 0x00040;
O_EXCL     :: 0x00080;
O_NOCTTY   :: 0x00100;
O_TRUNC    :: 0x00200;
O_NONBLOCK :: 0x00800;
O_APPEND   :: 0x00400;
O_SYNC     :: 0x01000;
O_ASYNC    :: 0x02000;
O_CLOEXEC  :: 0x80000;


SEEK_SET   :: 0;
SEEK_CUR   :: 1;
SEEK_END   :: 2;
SEEK_DATA  :: 3;
SEEK_HOLE  :: 4;
SEEK_MAX   :: SEEK_HOLE;

// NOTE(zangent): These are OS specific!
// Do not mix these up!
RTLD_LAZY         :: 0x001;
RTLD_NOW          :: 0x002;
RTLD_BINDING_MASK :: 0x3;
RTLD_GLOBAL       :: 0x100;

// "Argv" arguments converted to Odin strings
args := _alloc_command_line_arguments();

_File_Time :: struct {
	seconds:     i64,
	nanoseconds: i64,
}

Stat :: struct {
	device_id:     u64, // ID of device containing file
	serial:        u64, // File serial number
	nlink:         u64, // Number of hard links
	mode:          u32, // Mode of the file
	uid:           u32, // User ID of the file's owner
	gid:           u32, // Group ID of the file's group
	_padding:      i32, // 32 bits of padding
	rdev:          u64, // Device ID, if device
	size:          i64, // Size of the file, in bytes
	block_size:    i64, // Optimal bllocksize for I/O
	blocks:        i64, // Number of 512-byte blocks allocated

	last_access:   _File_Time, // Time of last access
	modified:      _File_Time, // Time of last modification
	status_change: _File_Time, // Time of last status change

	_reserve1,
	_reserve2,
	_reserve3:     i64,
};

// File type
S_IFMT   :: 0o170000; // Type of file mask
S_IFIFO  :: 0o010000; // Named pipe (fifo)
S_IFCHR  :: 0o020000; // Character special
S_IFDIR  :: 0o040000; // Directory
S_IFBLK  :: 0o060000; // Block special
S_IFREG  :: 0o100000; // Regular
S_IFLNK  :: 0o120000; // Symbolic link
S_IFSOCK :: 0o140000; // Socket

// File mode
// Read, write, execute/search by owner
S_IRWXU :: 0o0700; // RWX mask for owner
S_IRUSR :: 0o0400; // R for owner
S_IWUSR :: 0o0200; // W for owner
S_IXUSR :: 0o0100; // X for owner

	// Read, write, execute/search by group
S_IRWXG :: 0o0070; // RWX mask for group
S_IRGRP :: 0o0040; // R for group
S_IWGRP :: 0o0020; // W for group
S_IXGRP :: 0o0010; // X for group

	// Read, write, execute/search by others
S_IRWXO :: 0o0007; // RWX mask for other
S_IROTH :: 0o0004; // R for other
S_IWOTH :: 0o0002; // W for other
S_IXOTH :: 0o0001; // X for other

S_ISUID :: 0o4000; // Set user id on execution
S_ISGID :: 0o2000; // Set group id on execution
S_ISVTX :: 0o1000; // Directory restrcted delete


S_ISLNK  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFLNK;
S_ISREG  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFREG;
S_ISDIR  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFDIR;
S_ISCHR  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFCHR;
S_ISBLK  :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFBLK;
S_ISFIFO :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFIFO;
S_ISSOCK :: inline proc(m: u32) -> bool do return (m & S_IFMT) == S_IFSOCK;

F_OK :: 0; // Test for file existance
X_OK :: 1; // Test for execute permission
W_OK :: 2; // Test for write permission
R_OK :: 4; // Test for read permission

SYS_GETTID: Syscall : 186;

foreign libc {
	@(link_name="__errno_location") __errno_location    :: proc() -> ^int ---;
	@(link_name="syscall")          syscall             :: proc(number: Syscall, #c_vararg args: ..any) -> int ---;

	@(link_name="open")             _unix_open          :: proc(path: cstring, flags: int, #c_vararg mode: ..any) -> Handle ---;
	@(link_name="close")            _unix_close         :: proc(fd: Handle) -> int ---;
	@(link_name="read")             _unix_read          :: proc(fd: Handle, buf: rawptr, size: int) -> int ---;
	@(link_name="write")            _unix_write         :: proc(fd: Handle, buf: rawptr, size: int) -> int ---;
	@(link_name="lseek64")          _unix_seek          :: proc(fd: Handle, offset: i64, whence: i32) -> i64 ---;
	@(link_name="gettid")           _unix_gettid        :: proc() -> u64 ---;
	@(link_name="getpagesize")      _unix_getpagesize   :: proc() -> i32 ---;
	@(link_name="stat")             _unix_stat          :: proc(path: cstring, stat: ^Stat) -> int ---;
	@(link_name="fstat")            _unix_fstat         :: proc(fd: Handle, stat: ^Stat) -> int ---;
	@(link_name="access")           _unix_access        :: proc(path: cstring, mask: int) -> int ---;

	@(link_name="malloc")           _unix_malloc        :: proc(size: int) -> rawptr ---;
	@(link_name="calloc")           _unix_calloc        :: proc(num, size: int) -> rawptr ---;
	@(link_name="free")             _unix_free          :: proc(ptr: rawptr) ---;
	@(link_name="realloc")          _unix_realloc       :: proc(ptr: rawptr, size: int) -> rawptr ---;
	@(link_name="getenv")           _unix_getenv        :: proc(cstring) -> cstring ---;

	@(link_name="exit")             _unix_exit          :: proc(status: int) -> ! ---;
}
foreign dl {
	@(link_name="dlopen")           _unix_dlopen        :: proc(filename: cstring, flags: int) -> rawptr ---;
	@(link_name="dlsym")            _unix_dlsym         :: proc(handle: rawptr, symbol: cstring) -> rawptr ---;
	@(link_name="dlclose")          _unix_dlclose       :: proc(handle: rawptr) -> int ---;
	@(link_name="dlerror")          _unix_dlerror       :: proc() -> cstring ---;
}

is_path_separator :: proc(r: rune) -> bool {
	return r == '/';
}

get_last_error :: proc() -> int {
	return __errno_location()^;
}

open :: proc(path: string, flags: int = O_RDONLY, mode: int = 0) -> (Handle, Errno) {
	cstr := strings.clone_to_cstring(path);
	handle := _unix_open(cstr, flags, mode);
	delete(cstr);
	if handle == -1 {
		return INVALID_HANDLE, Errno(get_last_error());
	}
	return handle, ERROR_NONE;
}

close :: proc(fd: Handle) -> Errno {
	result := _unix_close(fd);
	if result == -1 {
		return Errno(get_last_error());
	}
	return ERROR_NONE;
}

read :: proc(fd: Handle, data: []byte) -> (int, Errno) {
	bytes_read := _unix_read(fd, &data[0], len(data));
	if bytes_read == -1 {
		return -1, Errno(get_last_error());
	}
	return bytes_read, ERROR_NONE;
}

write :: proc(fd: Handle, data: []byte) -> (int, Errno) {
	if len(data) == 0 {
		return 0, ERROR_NONE;
	}
	bytes_written := _unix_write(fd, &data[0], len(data));
	if bytes_written == -1 {
		return -1, Errno(get_last_error());
	}
	return bytes_written, ERROR_NONE;
}

seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Errno) {
	res := _unix_seek(fd, offset, i32(whence));
	if res == -1 {
		return -1, Errno(get_last_error());
	}
	return res, ERROR_NONE;
}

file_size :: proc(fd: Handle) -> (i64, Errno) {
	s, err := fstat(fd);
	if err != ERROR_NONE {
		return -1, err;
	}
	return s.size, ERROR_NONE;
}


// NOTE(bill): Uses startup to initialize it

stdin:  Handle = 0;
stdout: Handle = 1;
stderr: Handle = 2;

/* TODO(zangent): Implement these!
last_write_time :: proc(fd: Handle) -> File_Time {}
last_write_time_by_name :: proc(name: string) -> File_Time {}
*/
last_write_time :: proc(fd: Handle) -> (File_Time, Errno) {
	s, err := fstat(fd);
	if err != ERROR_NONE {
		return 0, err;
	}
	return File_Time(s.modified.nanoseconds), ERROR_NONE;
}

last_write_time_by_name :: proc(name: string) -> (File_Time, Errno) {
	s, err := stat(name);
	if err != ERROR_NONE {
		return 0, err;
	}
	return File_Time(s.modified.nanoseconds), ERROR_NONE;
}

stat :: inline proc(path: string) -> (Stat, Errno) {
	cstr := strings.clone_to_cstring(path);
	defer delete(cstr);

	s: Stat;
	result := _unix_stat(cstr, &s);
	if result == -1 {
		return s, Errno(get_last_error());
	}
	return s, ERROR_NONE;
}

fstat :: inline proc(fd: Handle) -> (Stat, Errno) {
	s: Stat;
	result := _unix_fstat(fd, &s);
	if result == -1 {
		return s, Errno(get_last_error());
	}
	return s, ERROR_NONE;
}

access :: inline proc(path: string, mask: int) -> (bool, Errno) {
	cstr := strings.clone_to_cstring(path);
	defer delete(cstr);
	result := _unix_access(cstr, mask);
	if result == -1 {
		return false, Errno(get_last_error());
	}
	return true, ERROR_NONE;
}

heap_alloc :: proc(size: int) -> rawptr {
	assert(size >= 0);
	return _unix_calloc(1, size);
}

heap_resize :: proc(ptr: rawptr, new_size: int) -> rawptr {
	return _unix_realloc(ptr, new_size);
}

heap_free :: proc(ptr: rawptr) {
	_unix_free(ptr);
}

getenv :: proc(name: string) -> (string, bool) {
	path_str := strings.clone_to_cstring(name);
	defer delete(path_str);
	cstr := _unix_getenv(path_str);
	if cstr == nil {
		return "", false;
	}
	return string(cstr), true;
}

exit :: proc(code: int) -> ! {
	_unix_exit(code);
}

current_thread_id :: proc "contextless" () -> int {
	return syscall(SYS_GETTID);
}

dlopen :: inline proc(filename: string, flags: int) -> rawptr {
	cstr := strings.clone_to_cstring(filename);
	defer delete(cstr);
	handle := _unix_dlopen(cstr, flags);
	return handle;
}
dlsym :: inline proc(handle: rawptr, symbol: string) -> rawptr {
	assert(handle != nil);
	cstr := strings.clone_to_cstring(symbol);
	defer delete(cstr);
	proc_handle := _unix_dlsym(handle, cstr);
	return proc_handle;
}
dlclose :: inline proc(handle: rawptr) -> bool {
	assert(handle != nil);
	return _unix_dlclose(handle) == 0;
}
dlerror :: proc() -> string {
	return string(_unix_dlerror());
}

get_page_size :: proc() -> int {
	// NOTE(tetra): The page size never changes, so why do anything complicated
	// if we don't have to.
	@static page_size := -1;
	if page_size != -1 do return page_size;

	page_size = int(_unix_getpagesize());
	return page_size;
}


_alloc_command_line_arguments :: proc() -> []string {
	res := make([]string, len(runtime.args__));
	for arg, i in runtime.args__ {
		res[i] = string(arg);
	}
	return res;
}