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