2 * vim:ts=4:sw=4:expandtab
4 * i3bar - an xcb-based status- and ws-bar for i3
5 * © 2010 Axel Wagner and contributors (see also: LICENSE)
7 * child.c: Getting input for the statusline
12 #include <sys/types.h>
22 #include <yajl/yajl_common.h>
23 #include <yajl/yajl_parse.h>
24 #include <yajl/yajl_version.h>
25 #include <yajl/yajl_gen.h>
30 /* Global variables for child_*() */
33 /* stdin- and SIGCHLD-watchers */
37 /* JSON parser for stdin */
40 /* JSON generator for stdout */
43 typedef struct parser_ctx {
44 /* True if one of the parsed blocks was urgent */
47 /* A copy of the last JSON map key. */
50 /* The current block. Will be filled, then copied and put into the list of
52 struct status_block block;
55 parser_ctx parser_context;
57 struct statusline_head statusline_head = TAILQ_HEAD_INITIALIZER(statusline_head);
58 /* Used temporarily while reading a statusline */
59 struct statusline_head statusline_buffer = TAILQ_HEAD_INITIALIZER(statusline_buffer);
64 * Remove all blocks from the given statusline.
65 * If free_resources is set, the fields of each status block will be free'd.
67 static void clear_statusline(struct statusline_head *head, bool free_resources) {
68 struct status_block *first;
69 while (!TAILQ_EMPTY(head)) {
70 first = TAILQ_FIRST(head);
72 I3STRING_FREE(first->full_text);
73 I3STRING_FREE(first->short_text);
76 FREE(first->instance);
77 FREE(first->min_width_str);
78 FREE(first->background);
82 TAILQ_REMOVE(head, first, blocks);
87 static void copy_statusline(struct statusline_head *from, struct statusline_head *to) {
88 struct status_block *current;
89 TAILQ_FOREACH(current, from, blocks) {
90 struct status_block *new_block = smalloc(sizeof(struct status_block));
91 memcpy(new_block, current, sizeof(struct status_block));
92 TAILQ_INSERT_TAIL(to, new_block, blocks);
97 * Replaces the statusline in memory with an error message. Pass a format
98 * string and format parameters as you would in `printf'. The next time
99 * `draw_bars' is called, the error message text will be drawn on the bar in
100 * the space allocated for the statusline.
102 __attribute__((format(printf, 1, 2))) static void set_statusline_error(const char *format, ...) {
103 clear_statusline(&statusline_head, true);
107 va_start(args, format);
108 if (vasprintf(&message, format, args) == -1) {
112 struct status_block *err_block = scalloc(1, sizeof(struct status_block));
113 err_block->full_text = i3string_from_utf8("Error: ");
114 err_block->name = sstrdup("error");
115 err_block->color = sstrdup("red");
116 err_block->no_separator = true;
118 struct status_block *message_block = scalloc(1, sizeof(struct status_block));
119 message_block->full_text = i3string_from_utf8(message);
120 message_block->name = sstrdup("error_message");
121 message_block->color = sstrdup("red");
122 message_block->no_separator = true;
124 TAILQ_INSERT_HEAD(&statusline_head, err_block, blocks);
125 TAILQ_INSERT_TAIL(&statusline_head, message_block, blocks);
132 * Stop and free() the stdin- and SIGCHLD-watchers
136 if (stdin_io != NULL) {
137 ev_io_stop(main_loop, stdin_io);
141 if (child_sig != NULL) {
142 ev_child_stop(main_loop, child_sig);
146 memset(&child, 0, sizeof(i3bar_child));
150 * The start of a new array is the start of a new status line, so we clear all
151 * previous entries from the buffer.
153 static int stdin_start_array(void *context) {
154 // the blocks are still used by statusline_head, so we won't free the
156 clear_statusline(&statusline_buffer, false);
161 * The start of a map is the start of a single block of the status line.
164 static int stdin_start_map(void *context) {
165 parser_ctx *ctx = context;
166 memset(&(ctx->block), '\0', sizeof(struct status_block));
168 /* Default width of the separator block. */
169 if (config.separator_symbol == NULL)
170 ctx->block.sep_block_width = logical_px(9);
172 ctx->block.sep_block_width = logical_px(8) + separator_symbol_width;
177 static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
178 parser_ctx *ctx = context;
179 FREE(ctx->last_map_key);
180 sasprintf(&(ctx->last_map_key), "%.*s", len, key);
184 static int stdin_boolean(void *context, int val) {
185 parser_ctx *ctx = context;
186 if (strcasecmp(ctx->last_map_key, "urgent") == 0) {
187 ctx->block.urgent = val;
190 if (strcasecmp(ctx->last_map_key, "separator") == 0) {
191 ctx->block.no_separator = !val;
198 static int stdin_string(void *context, const unsigned char *val, size_t len) {
199 parser_ctx *ctx = context;
200 if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
201 ctx->block.full_text = i3string_from_markup_with_length((const char *)val, len);
204 if (strcasecmp(ctx->last_map_key, "short_text") == 0) {
205 ctx->block.short_text = i3string_from_markup_with_length((const char *)val, len);
208 if (strcasecmp(ctx->last_map_key, "color") == 0) {
209 sasprintf(&(ctx->block.color), "%.*s", len, val);
212 if (strcasecmp(ctx->last_map_key, "background") == 0) {
213 sasprintf(&(ctx->block.background), "%.*s", len, val);
216 if (strcasecmp(ctx->last_map_key, "border") == 0) {
217 sasprintf(&(ctx->block.border), "%.*s", len, val);
220 if (strcasecmp(ctx->last_map_key, "markup") == 0) {
221 ctx->block.pango_markup = (len == strlen("pango") && !strncasecmp((const char *)val, "pango", strlen("pango")));
224 if (strcasecmp(ctx->last_map_key, "align") == 0) {
225 if (len == strlen("center") && !strncmp((const char *)val, "center", strlen("center"))) {
226 ctx->block.align = ALIGN_CENTER;
227 } else if (len == strlen("right") && !strncmp((const char *)val, "right", strlen("right"))) {
228 ctx->block.align = ALIGN_RIGHT;
230 ctx->block.align = ALIGN_LEFT;
234 if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
235 sasprintf(&(ctx->block.min_width_str), "%.*s", len, val);
238 if (strcasecmp(ctx->last_map_key, "name") == 0) {
239 sasprintf(&(ctx->block.name), "%.*s", len, val);
242 if (strcasecmp(ctx->last_map_key, "instance") == 0) {
243 sasprintf(&(ctx->block.instance), "%.*s", len, val);
250 static int stdin_integer(void *context, long long val) {
251 parser_ctx *ctx = context;
252 if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
253 ctx->block.min_width = (uint32_t)val;
256 if (strcasecmp(ctx->last_map_key, "separator_block_width") == 0) {
257 ctx->block.sep_block_width = (uint32_t)val;
265 * When a map is finished, we have an entire status block.
266 * Move it from the parser's context to the statusline buffer.
268 static int stdin_end_map(void *context) {
269 parser_ctx *ctx = context;
270 struct status_block *new_block = smalloc(sizeof(struct status_block));
271 memcpy(new_block, &(ctx->block), sizeof(struct status_block));
272 /* Ensure we have a full_text set, so that when it is missing (or null),
273 * i3bar doesn’t crash and the user gets an annoying message. */
274 if (!new_block->full_text)
275 new_block->full_text = i3string_from_utf8("SPEC VIOLATION: full_text is NULL!");
276 if (new_block->urgent)
277 ctx->has_urgent = true;
279 if (new_block->min_width_str) {
280 i3String *text = i3string_from_utf8(new_block->min_width_str);
281 i3string_set_markup(text, new_block->pango_markup);
282 new_block->min_width = (uint32_t)predict_text_width(text);
286 i3string_set_markup(new_block->full_text, new_block->pango_markup);
288 if (new_block->short_text != NULL)
289 i3string_set_markup(new_block->short_text, new_block->pango_markup);
291 TAILQ_INSERT_TAIL(&statusline_buffer, new_block, blocks);
296 * When an array is finished, we have an entire statusline.
297 * Copy it from the buffer to the actual statusline.
299 static int stdin_end_array(void *context) {
300 DLOG("copying statusline_buffer to statusline_head\n");
301 clear_statusline(&statusline_head, true);
302 copy_statusline(&statusline_buffer, &statusline_head);
304 DLOG("dumping statusline:\n");
305 struct status_block *current;
306 TAILQ_FOREACH(current, &statusline_head, blocks) {
307 DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
308 DLOG("short_text = %s\n", (current->short_text == NULL ? NULL : i3string_as_utf8(current->short_text)));
309 DLOG("color = %s\n", current->color);
311 DLOG("end of dump\n");
316 * Helper function to read stdin
318 * Returns NULL on EOF.
321 static unsigned char *get_buffer(ev_io *watcher, int *ret_buffer_len) {
322 int fd = watcher->fd;
325 int buffer_len = STDIN_CHUNK_SIZE;
326 unsigned char *buffer = smalloc(buffer_len + 1);
329 n = read(fd, buffer + rec, buffer_len - rec);
331 if (errno == EAGAIN) {
335 ELOG("read() failed!: %s\n", strerror(errno));
339 ELOG("stdin: received EOF\n");
340 *ret_buffer_len = -1;
345 if (rec == buffer_len) {
346 buffer_len += STDIN_CHUNK_SIZE;
347 buffer = srealloc(buffer, buffer_len);
350 if (*buffer == '\0') {
354 *ret_buffer_len = rec;
358 static void read_flat_input(char *buffer, int length) {
359 struct status_block *first = TAILQ_FIRST(&statusline_head);
360 /* Clear the old buffer if any. */
361 I3STRING_FREE(first->full_text);
362 /* Remove the trailing newline and terminate the string at the same
364 if (buffer[length - 1] == '\n' || buffer[length - 1] == '\r')
365 buffer[length - 1] = '\0';
367 buffer[length] = '\0';
368 first->full_text = i3string_from_markup(buffer);
371 static bool read_json_input(unsigned char *input, int length) {
372 yajl_status status = yajl_parse(parser, input, length);
373 bool has_urgent = false;
374 if (status != yajl_status_ok) {
375 char *message = (char *)yajl_get_error(parser, 0, input, length);
377 /* strip the newline yajl adds to the error message */
378 if (message[strlen(message) - 1] == '\n')
379 message[strlen(message) - 1] = '\0';
381 fprintf(stderr, "[i3bar] Could not parse JSON input (code = %d, message = %s): %.*s\n",
382 status, message, length, input);
384 set_statusline_error("Could not parse JSON (%s)", message);
385 yajl_free_error(parser, (unsigned char *)message);
387 } else if (parser_context.has_urgent) {
394 * Callbalk for stdin. We read a line from stdin and store the result
398 void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
400 unsigned char *buffer = get_buffer(watcher, &rec);
403 bool has_urgent = false;
404 if (child.version > 0) {
405 has_urgent = read_json_input(buffer, rec);
407 read_flat_input((char *)buffer, rec);
410 draw_bars(has_urgent);
414 * Callbalk for stdin first line. We read the first line to detect
415 * whether this is JSON or plain text
418 void stdin_io_first_line_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
420 unsigned char *buffer = get_buffer(watcher, &rec);
423 DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
424 /* Detect whether this is JSON or plain text. */
425 unsigned int consumed = 0;
426 /* At the moment, we don’t care for the version. This might change
427 * in the future, but for now, we just discard it. */
428 parse_json_header(&child, buffer, rec, &consumed);
429 if (child.version > 0) {
430 /* If hide-on-modifier is set, we start of by sending the
431 * child a SIGSTOP, because the bars aren't mapped at start */
432 if (config.hide_on_modifier) {
435 draw_bars(read_json_input(buffer + consumed, rec - consumed));
437 /* In case of plaintext, we just add a single block and change its
438 * full_text pointer later. */
439 struct status_block *new_block = scalloc(1, sizeof(struct status_block));
440 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
441 read_flat_input((char *)buffer, rec);
444 ev_io_stop(main_loop, stdin_io);
445 ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
446 ev_io_start(main_loop, stdin_io);
450 * We received a SIGCHLD, meaning, that the child process terminated.
451 * We simply free the respective data structures and don't care for input
455 void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
456 int exit_status = WEXITSTATUS(watcher->rstatus);
458 ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
462 /* this error is most likely caused by a user giving a nonexecutable or
463 * nonexistent file, so we will handle those cases separately. */
464 if (exit_status == 126)
465 set_statusline_error("status_command is not executable (exit %d)", exit_status);
466 else if (exit_status == 127)
467 set_statusline_error("status_command not found or is missing a library dependency (exit %d)", exit_status);
469 set_statusline_error("status_command process exited unexpectedly (exit %d)", exit_status);
475 void child_write_output(void) {
476 if (child.click_events) {
477 const unsigned char *output;
481 yajl_gen_get_buf(gen, &output, &size);
483 n = writeall(child_stdin, output, size);
485 n = writeall(child_stdin, "\n", 1);
490 child.click_events = false;
492 set_statusline_error("child_write_output failed");
499 * Start a child process with the specified command and reroute stdin.
500 * We actually start a $SHELL to execute the command so we don't have to care
501 * about arguments and such.
503 * If `command' is NULL, such as in the case when no `status_command' is given
504 * in the bar config, no child will be started.
507 void start_child(char *command) {
511 /* Allocate a yajl parser which will be used to parse stdin. */
512 static yajl_callbacks callbacks = {
513 .yajl_boolean = stdin_boolean,
514 .yajl_integer = stdin_integer,
515 .yajl_string = stdin_string,
516 .yajl_start_map = stdin_start_map,
517 .yajl_map_key = stdin_map_key,
518 .yajl_end_map = stdin_end_map,
519 .yajl_start_array = stdin_start_array,
520 .yajl_end_array = stdin_end_array,
522 parser = yajl_alloc(&callbacks, NULL, &parser_context);
524 gen = yajl_gen_alloc(NULL);
526 int pipe_in[2]; /* pipe we read from */
527 int pipe_out[2]; /* pipe we write to */
529 if (pipe(pipe_in) == -1)
530 err(EXIT_FAILURE, "pipe(pipe_in)");
531 if (pipe(pipe_out) == -1)
532 err(EXIT_FAILURE, "pipe(pipe_out)");
537 ELOG("Couldn't fork(): %s\n", strerror(errno));
540 /* Child-process. Reroute streams and start shell */
545 dup2(pipe_in[1], STDOUT_FILENO);
546 dup2(pipe_out[0], STDIN_FILENO);
548 setpgid(child.pid, 0);
549 execl(_PATH_BSHELL, _PATH_BSHELL, "-c", command, (char *)NULL);
552 /* Parent-process. Reroute streams */
557 dup2(pipe_in[0], STDIN_FILENO);
558 child_stdin = pipe_out[1];
563 /* We set O_NONBLOCK because blocking is evil in event-driven software */
564 fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
566 stdin_io = smalloc(sizeof(ev_io));
567 ev_io_init(stdin_io, &stdin_io_first_line_cb, STDIN_FILENO, EV_READ);
568 ev_io_start(main_loop, stdin_io);
570 /* We must cleanup, if the child unexpectedly terminates */
571 child_sig = smalloc(sizeof(ev_child));
572 ev_child_init(child_sig, &child_sig_cb, child.pid, 0);
573 ev_child_start(main_loop, child_sig);
575 atexit(kill_child_at_exit);
578 void child_click_events_initialize(void) {
579 if (!child.click_events_init) {
580 yajl_gen_array_open(gen);
581 child_write_output();
582 child.click_events_init = true;
586 void child_click_events_key(const char *key) {
587 yajl_gen_string(gen, (const unsigned char *)key, strlen(key));
591 * Generates a click event, if enabled.
594 void send_block_clicked(int button, const char *name, const char *instance, int x, int y) {
595 if (!child.click_events) {
599 child_click_events_initialize();
601 yajl_gen_map_open(gen);
604 child_click_events_key("name");
605 yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
609 child_click_events_key("instance");
610 yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
613 child_click_events_key("button");
614 yajl_gen_integer(gen, button);
616 child_click_events_key("x");
617 yajl_gen_integer(gen, x);
619 child_click_events_key("y");
620 yajl_gen_integer(gen, y);
622 yajl_gen_map_close(gen);
623 child_write_output();
627 * kill()s the child process (if any). Called when exit()ing.
630 void kill_child_at_exit(void) {
632 if (child.cont_signal > 0 && child.stopped)
633 killpg(child.pid, child.cont_signal);
634 killpg(child.pid, SIGTERM);
639 * kill()s the child process (if existent) and closes and
640 * free()s the stdin- and SIGCHLD-watchers
643 void kill_child(void) {
645 if (child.cont_signal > 0 && child.stopped)
646 killpg(child.pid, child.cont_signal);
647 killpg(child.pid, SIGTERM);
649 waitpid(child.pid, &status, 0);
655 * Sends a SIGSTOP to the child process (if existent)
658 void stop_child(void) {
659 if (child.stop_signal > 0 && !child.stopped) {
660 child.stopped = true;
661 killpg(child.pid, child.stop_signal);
666 * Sends a SIGCONT to the child process (if existent)
669 void cont_child(void) {
670 if (child.cont_signal > 0 && child.stopped) {
671 child.stopped = false;
672 killpg(child.pid, child.cont_signal);
677 * Whether or not the child want click events
680 bool child_want_click_events(void) {
681 return child.click_events;