hare

[hare] The Hare programming language
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pty.ha (1962B)


      1 // SPDX-License-Identifier: MPL-2.0
      2 // (c) Hare authors <https://harelang.org>
      3 
      4 use errors;
      5 use fs;
      6 use io;
      7 use rt;
      8 use types::c;
      9 
     10 // Opens an available pseudoterminal and returns the file descriptors of the
     11 // master and slave.
     12 export fn openpty() ((io::file, io::file) | fs::error) = {
     13 	let master = open_master()?;
     14 	defer io::close(master)!;
     15 
     16 	let ptm = rt::ptmget { ... };
     17 	match (rt::ioctl(master, rt::PTMGET, &ptm)) {
     18 	case let e: rt::errno =>
     19 		return errors::errno(e);
     20 	case =>	void;
     21 	};
     22 
     23 	return (ptm.cfd, ptm.sfd);
     24 };
     25 
     26 // Opens an available pseudoterminal master.
     27 fn open_master() (io::file | fs::error) = {
     28 	match (rt::open(rt::PATH_PTMDEV, rt::O_RDWR, 0)) {
     29 	case let e: rt::errno =>
     30 		return errors::errno(e);
     31 	case let i: int =>
     32 		return io::fdopen(i);
     33 	};
     34 };
     35 
     36 // Returns the filename of the pseudoterminal slave.
     37 export fn ptsname(master: io::file) (str | error) = {
     38 	static let path_buf: [rt::PATH_MAX]u8 = [0...];
     39 
     40 	let name = match (rt::ptsname(master)) {
     41 	case let name: *u8 =>
     42 		yield name: *[*]u8;
     43 	case let err: rt::errno =>
     44 		switch (err) {
     45 		// master is not a pseudo-terminal device
     46 		case rt::EINVAL =>
     47 			return errors::unsupported;
     48 		// master is not an open valid file descriptor
     49 		case rt::EBADF =>
     50 			return errors::invalid;
     51 		case =>
     52 			abort("Unexpected error from ptsname");
     53 		};
     54 	};
     55 	let namelen = c::strlen(name: *const c::char);
     56 	path_buf[..namelen] = name[..namelen];
     57 
     58 	return c::tostrn(&path_buf: *const c::char, namelen)!;
     59 };
     60 
     61 // Sets the dimensions of the underlying pseudoterminal for an [[io::file]].
     62 export fn set_winsize(pty: io::file, sz: ttysize) (void | error) = {
     63 	let wsz = rt::winsize { ws_row = sz.rows, ws_col = sz.columns, ... };
     64 	match (rt::ioctl(pty, rt::TIOCSWINSZ, &wsz)) {
     65 	case let e: rt::errno =>
     66 		switch (e) {
     67 		case rt::EBADF, rt::EINVAL =>
     68 			return errors::invalid;
     69 		case rt::ENOTTY =>
     70 			return errors::unsupported;
     71 		case =>
     72 			abort("Unexpected error from ioctl");
     73 		};
     74 	case => void;
     75 	};
     76 };