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28d440ab KL |
1 | -*- coding: utf-8; -*- |
2 | GOAL | |
3 | ---- | |
4 | ||
5 | The ultimate goal of this branch is to implement support for opening | |
6 | multiple, different tty devices and simultaneous X and tty frames from | |
7 | a single Emacs session. | |
8 | ||
9 | WHO IS DOING IT | |
10 | --------------- | |
11 | ||
12 | I'm Károly Lőrentey. My address: lorentey@elte.hu. | |
13 | ||
14 | Patches or suggestions are welcome! | |
15 | ||
6548cf00 | 16 | Retrieving the latest version of the branch: |
4f0359de KL |
17 | |
18 | tla register-archive lorentey@elte.hu--2004 http://lorentey.web.elte.hu/arch/2004/ | |
19 | tla get lorentey@elte.hu--2004/emacs--multi-tty--0 <directory> | |
20 | ||
21 | (I use tla 1.1.) | |
22 | ||
28d440ab KL |
23 | |
24 | STATUS | |
25 | ------ | |
26 | ||
52c2ee2a KL |
27 | Basic multi-tty support is there; there are some rough edges, but it |
28 | already seems to be usable. Emacsclient has been extended to support | |
29 | opening a new terminal frame. | |
28d440ab | 30 | |
04c3243c KL |
31 | To try it out, compile the multi-tty branch with the following |
32 | commands: | |
bc279d67 KL |
33 | |
34 | mkdir +build | |
35 | cd +build | |
36 | ../configure --with-x-toolkit=no --without-x | |
37 | make bootstrap | |
38 | ||
39 | then start up the emacs server (src/emacs, M-x server-start), and then | |
6548cf00 | 40 | (from a shell prompt on another terminal) start emacsclient with |
28d440ab | 41 | |
16c290d8 | 42 | lib-src/emacsclient -f /optional/file/names... |
28d440ab | 43 | |
04c3243c KL |
44 | You'll hopefully have two fully working, independent frames on |
45 | separate terminals. (This seems to be very useful, emacsclient starts | |
46 | up even faster than vi!) :-) You can close the newly opened frame and | |
47 | return to the shell without exiting Emacs by pressing C-x 5 0, i.e., | |
819b8f00 | 48 | delete-frame. Creating new frames on the same tty with C-x 5 2 |
04c3243c KL |
49 | works exactly as before. Suspending Emacs is disabled at the moment. |
50 | If you exit emacs, all terminals should be restored to their previous | |
51 | states. | |
52c2ee2a KL |
52 | |
53 | X, Mac, Windows and DOS support is broken, probably doesn't even | |
819b8f00 | 54 | compile -- this will be solved later. |
04c3243c KL |
55 | |
56 | Only tested on my GNU/Linux box. | |
6548cf00 | 57 | |
28d440ab KL |
58 | |
59 | NEWS | |
60 | ---- | |
61 | ||
62 | For the NEWS file: | |
63 | ||
64 | ** Support for multiple terminal devices has been added. You can | |
65 | specify a terminal device (`tty' parameter) and a terminal type | |
6548cf00 | 66 | (`tty-type' parameter) to `make-terminal-frame'. `tty' must be a |
52c2ee2a | 67 | terminal device created by the updated emacsclient, or there will |
0a125897 | 68 | be problems with terminal input and window resizes. |
6548cf00 KL |
69 | |
70 | You can test for the presence of multiple terminal support by | |
71 | testing for the `multi-tty' feature. | |
72 | ||
73 | ** A make-frame-on-tty function has been added to make it easier to | |
74 | create frames on new terminals. | |
28d440ab | 75 | |
819b8f00 KL |
76 | ** New functions: frame-tty-name, frame-tty-type for accessing |
77 | terminal parameters, and delete-tty for closing the terminal | |
78 | device. | |
79 | ||
9628b887 KL |
80 | ** Emacsclient has been extended to support opening a new terminal |
81 | frame. | |
28d440ab KL |
82 | |
83 | CHANGELOG | |
84 | --------- | |
85 | ||
86 | See arch logs. | |
87 | ||
88 | ||
6548cf00 KL |
89 | DIARY OF CHANGES |
90 | ---------------- | |
91 | ||
92 | (ex-TODO items with explanations.) | |
28d440ab KL |
93 | |
94 | -- Introduce a new abstraction for terminal devices. | |
95 | ||
96 | (Done, see struct tty_output. The abstraction is not yet | |
97 | complete.) | |
98 | ||
28d440ab KL |
99 | -- Change the bootstrap procedure to initialize tty_list. |
100 | ||
101 | (Done, but needs review.) | |
102 | ||
28d440ab KL |
103 | -- Change make-terminal-frame to support specifying another tty. |
104 | ||
105 | (Done, new frame parameters: `tty' and `tty-type'.) | |
106 | ||
9628b887 KL |
107 | -- Implement support for reading from multiple terminals. |
108 | ||
109 | (Done, read_avail_input tries to read from each terminal, until one | |
28d7d09f | 110 | succeeds. MULTI_KBOARD is not used. Secondary terminals don't send |
6548cf00 | 111 | SIGIO!) |
9628b887 | 112 | |
819b8f00 KL |
113 | (Update: They do, now.) |
114 | ||
9628b887 | 115 | -- other-frame should cycle through the frames on the `current' |
6548cf00 | 116 | terminal only. |
9628b887 | 117 | |
6548cf00 | 118 | (Done, by trivially modifiying next_frame and prev_frame.) |
9628b887 KL |
119 | |
120 | -- Support different terminal sizes. | |
121 | ||
122 | (Done, no problem.) | |
123 | ||
124 | -- Make sure terminal resizes are handled gracefully. (Could be | |
125 | problematic.) | |
126 | ||
6548cf00 KL |
127 | (Done. We don't get automatic SIGWINCH for additional ttys, |
128 | though.) | |
9628b887 KL |
129 | |
130 | -- Extend emacsclient to automatically open a new tty when it connects | |
131 | to Emacs. | |
132 | ||
133 | (Done. It's an ugly hack, needs more work.) | |
134 | ||
52c2ee2a KL |
135 | -- Redisplay must refresh the topmost frame on *all* terminals, not |
136 | just the initial terminal. | |
9628b887 | 137 | |
52c2ee2a | 138 | (Done, but introduced an ugly redisplay problems. Ugh.) |
9628b887 | 139 | |
6548cf00 KL |
140 | -- Fix redisplay problems. |
141 | ||
52c2ee2a KL |
142 | (Done; it turned out that the entire Wcm structure must be moved |
143 | inside tty_output. Why didn't I catch this earlier?) | |
6548cf00 KL |
144 | |
145 | -- Provide a way for emacsclient to tell Emacs that the tty has been | |
146 | resized. | |
147 | ||
148 | (Done, simply forward the SIGWINCH signal.) | |
149 | ||
150 | -- Each keypress should automatically select the frame corresponding | |
151 | to the terminal that it was coming from. This means that Emacs | |
152 | must know from which terminal the last keyboard event came from. | |
6548cf00 | 153 | |
52c2ee2a KL |
154 | (Done, it was quite simple, the input event system already |
155 | supported multiple frames.) | |
6548cf00 KL |
156 | |
157 | -- Fix SIGIO issue with secondary terminals. | |
158 | ||
159 | (Done, emacsclient signals Emacs after writing to the proxy pseudo | |
52c2ee2a KL |
160 | terminal. Note that this means that multi-tty does not work with |
161 | raw ttys!) | |
28d440ab | 162 | |
0a125897 KL |
163 | (Update: This is bullshit. There is a read_input_waiting function, |
164 | extend that somehow.) | |
165 | ||
819b8f00 KL |
166 | (Update of update: The first update was not right either, extending |
167 | read_input_waiting was not necessary. Secondary ttys do seem to | |
168 | send signals on input.) | |
169 | ||
fca177d4 KL |
170 | -- Make make-terminal-frame look up the `tty' and `tty-type' frame |
171 | parameters from the currently selected terminal before the global | |
172 | default. | |
173 | ||
174 | (Done.) | |
175 | ||
176 | -- Put all cached terminal escape sequences into struct tty_output. | |
177 | Currently, they are still stored in global variables, so we don't | |
178 | really support multiple terminal types. | |
179 | ||
52c2ee2a | 180 | (Done. It was not fun.) |
fca177d4 KL |
181 | |
182 | -- Implement sane error handling after initialization. (Currently | |
6548cf00 KL |
183 | emacs exits if you specify a bad terminal type.) The helpful error |
184 | messages must still be provided when Emacs starts. | |
185 | ||
fca177d4 KL |
186 | (Done.) |
187 | ||
188 | -- Implement terminal deletion, i.e., deleting local frames, closing | |
189 | the tty device and restoring its previous state without exiting | |
190 | Emacs. | |
9628b887 | 191 | |
fca177d4 KL |
192 | (Done, but at the moment only called when an error happens during |
193 | initialization. There is a memory corruption error around this | |
194 | somewhere.) | |
195 | ||
8303ba32 KL |
196 | -- Implement automatic deletion of terminals when the last frame on |
197 | that terminal is closed. | |
198 | ||
199 | (Done.) | |
200 | ||
0a125897 KL |
201 | -- Restore tty screen after closing the terminal. |
202 | ||
203 | (Done, we do the same as Emacs 21.2 for all terminals.) | |
204 | ||
205 | -- 'TERM=dumb src/emacs' does not restore the terminal state. | |
206 | ||
207 | (Done.) | |
fca177d4 | 208 | |
b2af72d2 KL |
209 | -- C-g should work on secondary terminals. |
210 | ||
211 | (Done, but the binding is not configurable.) | |
212 | ||
213 | -- Deal with SIGHUP in Emacs and in emacsclient. (After this, the | |
214 | server-frames may be removed from server.el.) | |
215 | ||
216 | (Done, nothing to do. It seems that Emacs does not receive SIGHUP | |
217 | from secondary ttys.) | |
218 | ||
219 | -- Change emacsclient/server.el to support the -h argument better, | |
220 | i.e. automatically close the socket when the frame is closed. | |
221 | ||
222 | (Seems to be working OK.) | |
223 | ||
16c290d8 | 224 | -- Fix mysterious memory corruption error with tty deletion. To |
fca177d4 KL |
225 | trigger it, try the following shell command: |
226 | ||
227 | while true; do TERM=no-such-terminal-definition emacsclient -h; done | |
228 | ||
229 | Emacs usually dumps core after a few dozen iterations. (The bug | |
230 | seems to be related to the xfree()ing or bzero()ing of | |
9d9f1812 KL |
231 | tty_output.Wcm. Maybe there are outside references to struct Wcm? |
232 | Why were these vars collected into a struct before multi-tty | |
233 | support?) | |
fca177d4 | 234 | |
16c290d8 KL |
235 | (Done. Whew. It turned out that the problem had nothing to do |
236 | with hypothetical external references to Wcm, or any other | |
237 | tty_output component; it was simply that delete_tty closed the | |
238 | filehandles of secondary ttys twice, resulting in fclose doubly | |
239 | free()ing memory. Utterly trivial matter. I love the C's memory | |
240 | management, it puts hair on your chest.) | |
241 | ||
819b8f00 KL |
242 | -- Support raw secondary terminals. (Note that SIGIO works only on |
243 | the controlling terminal.) Hint: extend read_input_waiting() for | |
244 | multiple ttys and hopefully this will be fixed. | |
fca177d4 | 245 | |
819b8f00 KL |
246 | (Done, it seems to have been working already for some time. It |
247 | seems F_SETOWN does work, after all. Not sure what made it fail | |
248 | earlier, but it seems to be fixed (there were several changes | |
249 | around request_sigio, maybe one of them did it). | |
250 | read_input_waiting() is only used in sys_select(), don't change | |
251 | it.) | |
c1c63edb | 252 | |
819b8f00 | 253 | -- Find out why does Emacs abort when it wants to close its |
0a125897 | 254 | controlling tty. Hint: chan_process[] array. Hey, maybe |
16c290d8 KL |
255 | noninterrupt-IO would work, too? Update: no, there is no process |
256 | for stdin/out. | |
c33d2d42 | 257 | |
819b8f00 KL |
258 | (Done. Added add/delete_keyboard_wait_descriptor to |
259 | term_init/delete_tty. The hint was right, in a way.) | |
6548cf00 | 260 | |
819b8f00 | 261 | -- Issue with SIGIO: it needs to be disabled during redisplay. See if |
0a125897 KL |
262 | fcntl() kernel behaviour could be emulated by emacsclient. |
263 | ||
819b8f00 | 264 | (Done. Simply disabled the SIGIO emulation hack in emacsclient.) |
22de1e79 | 265 | |
819b8f00 | 266 | -- server.el: There are issues with saving files in buffers of closed |
16c290d8 KL |
267 | clients. Try editing a file with emacsclient -f, and (without |
268 | saving it) do a delete-frame. The frame is closed without | |
269 | question, and a surprising confirmation prompt appears in another | |
270 | frame. | |
271 | ||
819b8f00 KL |
272 | (Done. delete-frame now asks for confirmation if it still has |
273 | pending buffers, and modified buffers don't seem to be deleted.) | |
274 | ||
275 | -- emacsclient.el, server.el: Handle eval or file open errors when | |
16c290d8 KL |
276 | doing -f. |
277 | ||
819b8f00 | 278 | (Done.) |
22de1e79 | 279 | |
819b8f00 KL |
280 | -- Make parts of struct tty_output accessible from Lisp. The device |
281 | name and the type is sufficient. | |
22de1e79 | 282 | |
819b8f00 KL |
283 | (Done, see frame-tty-name and frame-tty-type.) |
284 | ||
285 | -- Export delete_tty to the Lisp environment, for emacsclient. | |
22de1e79 | 286 | |
819b8f00 KL |
287 | (Done, see delete-tty.) |
288 | ||
289 | ||
290 | THINGS TO DO | |
291 | ------------ | |
28d440ab | 292 | |
c33d2d42 | 293 | ** Find out the best way to support suspending Emacs with multiple |
819b8f00 KL |
294 | ttys. My guess: disable it on the controlling tty, but other ttys |
295 | should pass it on to emacsclient somehow. (It is (I hope) trivial | |
296 | to extend emacsclient to handle suspend/resume. A `kill -STOP' | |
297 | almost works right now.) | |
298 | ||
299 | ** Move baud_rate to tty_output. | |
300 | ||
301 | ** Move device-specific parameters (like costs) commonly used by | |
302 | device backends to a common, device-dependent structure. | |
c33d2d42 | 303 | |
c1c63edb | 304 | ** Do tty output through term_hooks, like graphical display backends. |
6548cf00 | 305 | |
52c2ee2a KL |
306 | ** Fix X support. |
307 | ||
c1c63edb | 308 | ** Allow simultaneous X and tty frames. (Handling input could be |
28d7d09f | 309 | tricky. Or maybe not.) |
28d440ab | 310 | |
819b8f00 KL |
311 | ** Implement support for starting an interactive Emacs session without |
312 | an initial frame. (The user would connect to it and open frames | |
313 | later, with emacsclient.) Not necessarily a good idea. | |
314 | ||
28d440ab KL |
315 | ** Fix Mac support (I can't do this myself). |
316 | ||
317 | ** Fix W32 support (I can't do this myself). | |
318 | ||
319 | ** Fix DOS support (I can't do this myself). | |
320 | ||
16c290d8 | 321 | ** Do a grep on XXX and ?? for more issues. |
28d440ab | 322 | |
819b8f00 KL |
323 | ** Get rid of the accessor macros in termchar.h, or define macros for |
324 | all members. | |
325 | ||
326 | ** Understand Emacs's low-level input system (it seems complicated) :-) | |
327 | and maybe rewrite multi-tty input in terms of MULTIKBOARD. | |
328 | ||
329 | ** What does interrupt_input do? I tried to disable it for raw | |
330 | secondary tty support, but it does not seem to do anything useful. | |
331 | ||
332 | ** Make sure C-g goes to the right frame. This is hard, as SIGINT | |
333 | doesn't have a tty parameter. :-( | |
334 | ||
28d7d09f KL |
335 | ** I have seen a case when Emacs with multiple ttys fell into a loop |
336 | eating 100% of CPU time. Strace showed this loop: | |
819b8f00 KL |
337 | |
338 | ||
339 | getpid() = 30284 | |
340 | kill(30284, SIGIO) = 0 | |
341 | --- SIGIO (I/O possible) @ 0 (0) --- | |
342 | ioctl(6, FIONREAD, [0]) = -1 EIO (Input/output error) | |
343 | ioctl(5, FIONREAD, [0]) = -1 EIO (Input/output error) | |
344 | ioctl(0, FIONREAD, [0]) = 0 | |
345 | sigreturn() = ? (mask now []) | |
346 | gettimeofday({1072842297, 747760}, NULL) = 0 | |
347 | gettimeofday({1072842297, 747806}, NULL) = 0 | |
348 | select(9, [0 3 5 6], NULL, NULL, {0, 0}) = 2 (in [5 6], left {0, 0}) | |
349 | select(9, [0 3 5 6], NULL, NULL, {0, 0}) = 2 (in [5 6], left {0, 0}) | |
350 | gettimeofday({1072842297, 748245}, NULL) = 0 | |
351 | ||
352 | I have not been able to reproduce this. | |
353 | ||
28d440ab | 354 | ;;; arch-tag: 8da1619e-2e79-41a8-9ac9-a0485daad17d |