f75e4be531d94521bf87f8baf19b5f4dfb5b6739
[paraslash.git] / interactive.c
1 /*
2 * Copyright (C) 2011-2012 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file interactive.c Readline abstraction for interactive sessions. */
8
9 #include <regex.h>
10 #include <stdbool.h>
11 #include <curses.h>
12 #include <readline/readline.h>
13 #include <readline/history.h>
14 #include <sys/ioctl.h>
15 #include <assert.h>
16 #include <signal.h>
17
18 #include "para.h"
19 #include "fd.h"
20 #include "buffer_tree.h"
21 #include "list.h"
22 #include "sched.h"
23 #include "interactive.h"
24 #include "string.h"
25 #include "error.h"
26
27 struct i9e_private {
28 struct i9e_client_info *ici;
29 FILE *stderr_stream;
30 int num_columns;
31 char empty_line[1000];
32 struct task task;
33 struct btr_node *stdout_btrn;
34 bool line_handler_running;
35 bool input_eof;
36 bool caught_sigint;
37 bool caught_sigterm;
38 };
39 static struct i9e_private i9e_private, *i9ep = &i9e_private;
40
41 static bool is_prefix(const char *partial, const char *full, size_t len)
42 {
43 if (len == 0)
44 len = strlen(partial);
45 return !strncmp(partial, full, len);
46 }
47
48 /*
49 * Generator function for command completion. STATE lets us know whether
50 * to start from scratch; without any state (i.e. STATE == 0), then we
51 * start at the top of the list.
52 */
53 static char *command_generator(const char *text, int state)
54 {
55 static int list_index, len;
56 const char *name;
57 struct i9e_client_info *ici = i9ep->ici;
58
59 rl_attempted_completion_over = 1; /* disable filename completion */
60 /*
61 * If this is a new word to complete, initialize now. This includes
62 * saving the length of TEXT for efficiency, and initializing the index
63 * variable to 0.
64 */
65 if (state == 0) {
66 list_index = 0;
67 len = strlen(text);
68 }
69 /* Return the next name which partially matches from the command list. */
70 while ((name = ici->completers[list_index].name)) {
71 list_index++;
72 if (is_prefix(text, name, len))
73 return para_strdup(name);
74 }
75 return NULL; /* no names matched */
76 }
77
78 static void reset_completion_result(struct i9e_completion_result *cr)
79 {
80 cr->dont_append_space = false;
81 cr->filename_completion_desired = false;
82 cr->matches = NULL;
83 }
84
85 static void create_matches(struct i9e_completion_info *ci,
86 struct i9e_completer *completers,
87 struct i9e_completion_result *cr)
88 {
89 int i, ret;
90
91 reset_completion_result(cr);
92
93 ret = create_argv(ci->buffer, " ", &ci->argv);
94 if (ret < 0 || !ci->argv[0])
95 return;
96
97 ci->argc = ret;
98 ci->word_num = compute_word_num(ci->buffer, " ", ci->point);
99 for (i = 0; completers[i].name; i++) {
100 if (strcmp(completers[i].name, ci->argv[0]) != 0)
101 continue;
102 completers[i].completer(ci, cr);
103 break;
104 }
105 PARA_DEBUG_LOG("current word: %d (%s)\n", ci->word_num,
106 ci->argv[ci->word_num]);
107 if (cr->matches)
108 for (i = 0; cr->matches[i]; i++)
109 PARA_DEBUG_LOG("match %d: %s\n", i, cr->matches[i]);
110 }
111
112 static char *completion_generator(const char *word, int state)
113 {
114 static int list_index;
115 static char **argv, **matches;
116 struct i9e_completer *completers = i9ep->ici->completers;
117 struct i9e_completion_info ci = {
118 .word = (char *)word,
119 .point = rl_point,
120 .buffer = rl_line_buffer,
121 };
122 struct i9e_completion_result cr = {.matches = NULL};
123
124 if (state != 0)
125 goto out;
126 /* clean up previous matches and set defaults */
127 free(matches);
128 matches = NULL;
129 free_argv(argv);
130 argv = NULL;
131 list_index = 0;
132 rl_completion_append_character = ' ';
133 rl_completion_suppress_append = false;
134 rl_attempted_completion_over = true;
135
136 create_matches(&ci, completers, &cr);
137
138 matches = cr.matches;
139 argv = ci.argv;
140 rl_completion_suppress_append = cr.dont_append_space;
141 rl_attempted_completion_over = !cr.filename_completion_desired;
142 out:
143 if (!matches)
144 return NULL;
145 return matches[list_index++];
146 }
147
148 /*
149 * Attempt to complete on the contents of TEXT. START and END bound the
150 * region of rl_line_buffer that contains the word to complete. TEXT is
151 * the word to complete. We can use the entire contents of rl_line_buffer
152 * in case we want to do some simple parsing. Return the array of matches,
153 * or NULL if there aren't any.
154 */
155 static char **i9e_completer(const char *text, int start, __a_unused int end)
156 {
157 struct i9e_client_info *ici = i9ep->ici;
158
159 if (!ici->completers)
160 return NULL;
161 /* Complete on command names if this is the first word in the line. */
162 if (start == 0)
163 return rl_completion_matches(text, command_generator);
164 return rl_completion_matches(text, completion_generator);
165 }
166
167 /**
168 * Prepare writing to stdout.
169 *
170 * \param producer The buffer tree node which produces output.
171 *
172 * The i9e subsystem maintains a buffer tree node which may be attached to
173 * another node which generates output (a "producer"). When attached, the i9e
174 * buffer tree node copies the buffers generated by the producer to stdout.
175 *
176 * This function attaches the i9e input queue to an output queue of \a
177 * producer.
178 *
179 * \return Standard.
180 */
181 void i9e_attach_to_stdout(struct btr_node *producer)
182 {
183 btr_remove_node(&i9ep->stdout_btrn);
184 i9ep->stdout_btrn = btr_new_node(&(struct btr_node_description)
185 EMBRACE(.name = "interactive_stdout", .parent = producer));
186 }
187
188 static void wipe_bottom_line(void)
189 {
190 fprintf(i9ep->stderr_stream, "\r%s\r", i9ep->empty_line);
191 }
192
193 /**
194 * Reset the terminal and save the in-memory command line history.
195 *
196 * This should be called before the caller exits.
197 */
198 void i9e_close(void)
199 {
200 char *hf = i9ep->ici->history_file;
201
202 rl_deprep_terminal();
203 if (hf)
204 write_history(hf);
205 wipe_bottom_line();
206 }
207
208 static void clear_bottom_line(void)
209 {
210 int point;
211 char *text;
212
213 if (rl_point == 0 && rl_end == 0)
214 return wipe_bottom_line();
215 /*
216 * We might have a multi-line input that needs to be wiped here, so the
217 * simple printf("\r<space>\r") is insufficient. To workaround this, we
218 * remove the whole line, redisplay and restore the killed text.
219 */
220 point = rl_point;
221 text = rl_copy_text(0, rl_end);
222 rl_kill_full_line(0, 0);
223 rl_redisplay();
224 wipe_bottom_line(); /* wipe out the prompt */
225 rl_insert_text(text);
226 rl_point = point;
227 }
228
229 static bool input_available(void)
230 {
231 fd_set rfds;
232 struct timeval tv = {0, 0};
233 int ret;
234
235 FD_ZERO(&rfds);
236 FD_SET(i9ep->ici->fds[0], &rfds);
237 ret = para_select(1, &rfds, NULL, &tv);
238 return ret > 0;
239 }
240
241 static void i9e_line_handler(char *line)
242 {
243 int ret;
244
245 ret = i9ep->ici->line_handler(line);
246 if (ret < 0)
247 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
248 rl_set_prompt("");
249 if (line) {
250 if (!*line)
251 rl_set_prompt(i9ep->ici->prompt);
252 else
253 add_history(line);
254 free(line);
255 } else {
256 rl_set_prompt("");
257 i9ep->input_eof = true;
258 }
259 }
260
261 static void i9e_input(void)
262 {
263 do {
264 rl_callback_read_char();
265 } while (input_available());
266 }
267
268 static void i9e_post_select(struct sched *s, struct task *t)
269 {
270 int ret;
271 struct btr_node *btrn = i9ep->stdout_btrn;
272 struct i9e_client_info *ici = i9ep->ici;
273 char *buf;
274 size_t sz;
275
276 ret = -E_I9E_EOF;
277 if (i9ep->input_eof)
278 goto rm_btrn;
279 ret = -E_I9E_TERM_RQ;
280 if (i9ep->caught_sigterm)
281 goto rm_btrn;
282 if (!btrn) {
283 i9ep->caught_sigint = false;
284 if (FD_ISSET(ici->fds[0], &s->rfds))
285 i9e_input();
286 return;
287 }
288 ret = 0;
289 if (i9ep->caught_sigint)
290 goto rm_btrn;
291 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
292 if (ret < 0)
293 goto rm_btrn;
294 sz = btr_next_buffer(btrn, &buf);
295 if (sz == 0)
296 goto out;
297 ret = xwrite(ici->fds[1], buf, sz);
298 if (ret < 0)
299 goto rm_btrn;
300 btr_consume(btrn, ret);
301 goto out;
302 rm_btrn:
303 btr_remove_node(&i9ep->stdout_btrn);
304 rl_set_prompt(i9ep->ici->prompt);
305 rl_redisplay();
306 out:
307 t->error = 0;
308 }
309
310 static void i9e_pre_select(struct sched *s, __a_unused struct task *t)
311 {
312 int ret;
313
314 if (i9ep->input_eof || i9ep->caught_sigint || i9ep->caught_sigterm) {
315 sched_min_delay(s);
316 return;
317 }
318 if (i9ep->stdout_btrn) {
319 ret = btr_node_status(i9ep->stdout_btrn, 0, BTR_NT_LEAF);
320 if (ret < 0) {
321 sched_min_delay(s);
322 return;
323 }
324 if (ret > 0)
325 para_fd_set(i9ep->ici->fds[1], &s->wfds, &s->max_fileno);
326 }
327 /*
328 * fd[0] might have been reset to blocking mode if our job was moved to
329 * the background due to CTRL-Z or SIGSTOP, so set the fd back to
330 * nonblocking mode.
331 */
332 ret = mark_fd_nonblocking(i9ep->ici->fds[0]);
333 if (ret < 0)
334 PARA_WARNING_LOG("set to nonblock failed: (fd0 %d, %s)\n",
335 i9ep->ici->fds[0], para_strerror(-ret));
336 para_fd_set(i9ep->ici->fds[0], &s->rfds, &s->max_fileno);
337 }
338
339 static void update_winsize(void)
340 {
341 struct winsize w;
342 int ret = ioctl(i9ep->ici->fds[2], TIOCGWINSZ, (char *)&w);
343
344 if (ret >= 0) {
345 assert(w.ws_col < sizeof(i9ep->empty_line));
346 i9ep->num_columns = w.ws_col;
347 } else
348 i9ep->num_columns = 80;
349
350 memset(i9ep->empty_line, ' ', i9ep->num_columns);
351 i9ep->empty_line[i9ep->num_columns] = '\0';
352 }
353
354 /**
355 * Register the i9e task and initialize readline.
356 *
357 * \param ici The i9e configuration parameters set by the caller.
358 * \param s The scheduler instance to add the i9e task to.
359 *
360 * The caller must allocate and initialize the structure \a ici points to.
361 *
362 * \return Standard.
363 * \sa \ref register_task().
364 */
365 int i9e_open(struct i9e_client_info *ici, struct sched *s)
366 {
367 int ret;
368
369 if (!isatty(ici->fds[0]))
370 return -E_I9E_SETUPTERM;
371 ret = mark_fd_nonblocking(ici->fds[0]);
372 if (ret < 0)
373 return ret;
374 ret = mark_fd_nonblocking(ici->fds[1]);
375 if (ret < 0)
376 return ret;
377 i9ep->task.pre_select = i9e_pre_select;
378 i9ep->task.post_select = i9e_post_select;
379 sprintf(i9ep->task.status, "i9e");
380 register_task(s, &i9ep->task);
381 rl_readline_name = "para_i9e";
382 rl_basic_word_break_characters = " ";
383 rl_attempted_completion_function = i9e_completer;
384 i9ep->ici = ici;
385 i9ep->stderr_stream = fdopen(ici->fds[2], "w");
386 setvbuf(i9ep->stderr_stream, NULL, _IONBF, 0);
387
388 if (ici->history_file)
389 read_history(ici->history_file);
390 update_winsize();
391 rl_callback_handler_install(i9ep->ici->prompt, i9e_line_handler);
392 return 1;
393 }
394
395 static void reset_line_state(void)
396 {
397 if (i9ep->stdout_btrn)
398 return;
399 rl_on_new_line();
400 rl_reset_line_state();
401 rl_forced_update_display();
402 }
403
404 /**
405 * The log function of the i9e subsystem.
406 *
407 * \param ll Severity log level.
408 * \param fmt Printf-like format string.
409 *
410 * This clears the bottom line of the terminal if necessary and writes the
411 * string given by \a fmt to fd[2], where fd[] is the array provided earlier in
412 * \ref i9e_open().
413 */
414 __printf_2_3 void i9e_log(int ll, const char* fmt,...)
415 {
416 va_list argp;
417
418 if (ll < i9ep->ici->loglevel)
419 return;
420 clear_bottom_line();
421 va_start(argp, fmt);
422 vfprintf(i9ep->stderr_stream, fmt, argp);
423 va_end(argp);
424 reset_line_state();
425 }
426
427 /**
428 * Tell i9e that the caller received a signal.
429 *
430 * \param sig_num The number of the signal received.
431 *
432 * Currently the function only cares about \p SIGINT, but this may change.
433 */
434 void i9e_signal_dispatch(int sig_num)
435 {
436 if (sig_num == SIGWINCH)
437 return update_winsize();
438 if (sig_num == SIGINT) {
439 fprintf(i9ep->stderr_stream, "\n");
440 rl_replace_line ("", false /* clear_undo */);
441 reset_line_state();
442 i9ep->caught_sigint = true;
443 }
444 if (sig_num == SIGTERM)
445 i9ep->caught_sigterm = true;
446 }
447
448 /**
449 * Wrapper for select(2) which does not restart on interrupts.
450 *
451 * \param n \sa \ref para_select().
452 * \param readfds \sa \ref para_select().
453 * \param writefds \sa \ref para_select().
454 * \param timeout_tv \sa \ref para_select().
455 *
456 * \return \sa \ref para_select().
457 *
458 * The only difference between this function and \ref para_select() is that
459 * \ref i9e_select() returns zero if the select call returned \p EINTR.
460 */
461 int i9e_select(int n, fd_set *readfds, fd_set *writefds,
462 struct timeval *timeout_tv)
463 {
464 int ret = select(n, readfds, writefds, NULL, timeout_tv);
465
466 if (ret < 0) {
467 if (errno == EINTR)
468 ret = 0;
469 else
470 ret = -ERRNO_TO_PARA_ERROR(errno);
471 }
472 return ret;
473 }
474
475 /**
476 * Return the possible completions for a given word.
477 *
478 * \param word The word to complete.
479 * \param string_list All possible words in this context.
480 * \param result String list is returned here.
481 *
482 * This function never fails. If no completion was found, a string list of
483 * length zero is returned. In any case, the result must be freed by the caller
484 * using \ref free_argv().
485 *
486 * This function is independent of readline and may be called before
487 * i9e_open().
488 *
489 * \return The number of possible completions.
490 */
491 int i9e_extract_completions(const char *word, char **string_list,
492 char ***result)
493 {
494 char **matches = para_malloc(sizeof(char *));
495 int match_count = 0, matches_len = 1;
496 char **p;
497 int len = strlen(word);
498
499 for (p = string_list; *p; p++) {
500 if (!is_prefix(word, *p, len))
501 continue;
502 match_count++;
503 if (match_count >= matches_len) {
504 matches_len *= 2;
505 matches = para_realloc(matches,
506 matches_len * sizeof(char *));
507 }
508 matches[match_count - 1] = para_strdup(*p);
509 }
510 matches[match_count] = NULL;
511 *result = matches;
512 return match_count;
513 }
514
515 /**
516 * Return the list of partially matching words.
517 *
518 * \param word The command to complete.
519 * \param completers The array containing all command names.
520 *
521 * This is similar to \ref i9e_extract_completions(), but completes on the
522 * command names in \a completers.
523 *
524 * \return See \ref i9e_extract_completions().
525 */
526 char **i9e_complete_commands(const char *word, struct i9e_completer *completers)
527 {
528 char **matches;
529 const char *cmd;
530 int i, match_count, len = strlen(word);
531
532 /*
533 * In contrast to completing against an arbitrary string list, here we
534 * know all possible completions and expect that there will not be many
535 * of them. So it should be OK to iterate twice over all commands which
536 * simplifies the code a bit.
537 */
538 for (i = 0, match_count = 0; (cmd = completers[i].name); i++) {
539 if (is_prefix(word, cmd, len))
540 match_count++;
541 }
542 matches = para_malloc((match_count + 1) * sizeof(*matches));
543 for (i = 0, match_count = 0; (cmd = completers[i].name); i++)
544 if (is_prefix(word, cmd, len))
545 matches[match_count++] = para_strdup(cmd);
546 matches[match_count] = NULL;
547 return matches;
548 }
549
550 /**
551 * Complete according to the given options.
552 *
553 * \param opts All available options.
554 * \param ci Information which was passed to the completer.
555 * \param cr Result pointer.
556 *
557 * This convenience helper can be used to complete an option. The array of all
558 * possible options is passed as the first argument. Flags, i.e. options
559 * without an argument, are expected to be listed as strings of type "-X" in \a
560 * opts while options which require an argument should be passed with a
561 * trailing "=" character like "-X=".
562 *
563 * If the word can be uniquely completed to a flag option, an additional space
564 * character is appended to the output. For non-flag options no space character
565 * is appended.
566 */
567 void i9e_complete_option(char **opts, struct i9e_completion_info *ci,
568 struct i9e_completion_result *cr)
569 {
570 int num_matches;
571
572 num_matches = i9e_extract_completions(ci->word, opts, &cr->matches);
573 if (num_matches == 1) {
574 char *opt = cr->matches[0];
575 char c = opt[strlen(opt) - 1];
576 if (c == '=')
577 cr->dont_append_space = true;
578 }
579 }
580
581 /**
582 * Print possible completions to stdout.
583 *
584 * \param completers The array of completion functions.
585 *
586 * At the end of the output a line starting with "-o=", followed by the
587 * (possibly empty) list of completion options is printed. Currently, the only
588 * two completion options are "nospace" and "filenames". The former indicates
589 * that no space should be appended even for a unique match while the latter
590 * indicates that usual filename completion should be performed in addition to
591 * the previously printed options.
592 *
593 * \return Standard.
594 */
595 int i9e_print_completions(struct i9e_completer *completers)
596 {
597 struct i9e_completion_result cr;
598 struct i9e_completion_info ci;
599 char *buf;
600 const char *end, *p;
601 int i, n, ret;
602
603 reset_completion_result(&cr);
604 buf = getenv("COMP_POINT");
605 ci.point = buf? atoi(buf) : 0;
606 ci.buffer = para_strdup(getenv("COMP_LINE"));
607
608 ci.argc = create_argv(ci.buffer, " ", &ci.argv);
609 ci.word_num = compute_word_num(ci.buffer, " ", ci.point);
610
611 end = ci.buffer + ci.point;
612 for (p = end; p > ci.buffer && *p != ' '; p--)
613 ; /* nothing */
614 if (*p == ' ')
615 p++;
616
617 n = end - p + 1;
618 ci.word = para_malloc(n + 1);
619 strncpy(ci.word, p, n);
620 ci.word[n] = '\0';
621
622 PARA_DEBUG_LOG("line: %s, point: %d (%c), wordnum: %d, word: %s\n",
623 ci.buffer, ci.point, ci.buffer[ci.point], ci.word_num, ci.word);
624 if (ci.word_num == 0)
625 cr.matches = i9e_complete_commands(ci.word, completers);
626 else
627 create_matches(&ci, completers, &cr);
628 ret = 0;
629 if (cr.matches && cr.matches[0]) {
630 for (i = 0; cr.matches[i]; i++)
631 printf("%s\n", cr.matches[i]);
632 ret = 1;
633 }
634 printf("-o=");
635 if (cr.dont_append_space)
636 printf("nospace");
637 if (cr.filename_completion_desired)
638 printf(",filenames");
639 printf("\n");
640 free_argv(cr.matches);
641 free_argv(ci.argv);
642 free(ci.buffer);
643 free(ci.word);
644 return ret;
645 }