2 * vim:ts=4:sw=4:expandtab
4 * i3bar - an xcb-based status- and ws-bar for i3
5 * © 2010-2012 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);
75 FREE(first->instance);
78 TAILQ_REMOVE(head, first, blocks);
83 static void copy_statusline(struct statusline_head *from, struct statusline_head *to) {
84 struct status_block *current;
85 TAILQ_FOREACH(current, from, blocks) {
86 struct status_block *new_block = smalloc(sizeof(struct status_block));
87 memcpy(new_block, current, sizeof(struct status_block));
88 TAILQ_INSERT_TAIL(to, new_block, blocks);
93 * Replaces the statusline in memory with an error message. Pass a format
94 * string and format parameters as you would in `printf'. The next time
95 * `draw_bars' is called, the error message text will be drawn on the bar in
96 * the space allocated for the statusline.
98 __attribute__((format(printf, 1, 2))) static void set_statusline_error(const char *format, ...) {
99 clear_statusline(&statusline_head, true);
103 va_start(args, format);
104 vasprintf(&message, format, args);
106 struct status_block *err_block = scalloc(sizeof(struct status_block));
107 err_block->full_text = i3string_from_utf8("Error: ");
108 err_block->name = "error";
109 err_block->color = "red";
110 err_block->no_separator = true;
112 struct status_block *message_block = scalloc(sizeof(struct status_block));
113 message_block->full_text = i3string_from_utf8(message);
114 message_block->name = "error_message";
115 message_block->color = "red";
116 message_block->no_separator = true;
118 TAILQ_INSERT_HEAD(&statusline_head, err_block, blocks);
119 TAILQ_INSERT_TAIL(&statusline_head, message_block, blocks);
126 * Stop and free() the stdin- and SIGCHLD-watchers
130 if (stdin_io != NULL) {
131 ev_io_stop(main_loop, stdin_io);
135 if (child_sig != NULL) {
136 ev_child_stop(main_loop, child_sig);
140 memset(&child, 0, sizeof(i3bar_child));
144 * The start of a new array is the start of a new status line, so we clear all
145 * previous entries from the buffer.
147 static int stdin_start_array(void *context) {
148 // the blocks are still used by statusline_head, so we won't free the
150 clear_statusline(&statusline_buffer, false);
155 * The start of a map is the start of a single block of the status line.
158 static int stdin_start_map(void *context) {
159 parser_ctx *ctx = context;
160 memset(&(ctx->block), '\0', sizeof(struct status_block));
162 /* Default width of the separator block. */
163 ctx->block.sep_block_width = logical_px(9);
168 static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
169 parser_ctx *ctx = context;
170 FREE(ctx->last_map_key);
171 sasprintf(&(ctx->last_map_key), "%.*s", len, key);
175 static int stdin_boolean(void *context, int val) {
176 parser_ctx *ctx = context;
177 if (strcasecmp(ctx->last_map_key, "urgent") == 0) {
178 ctx->block.urgent = val;
180 if (strcasecmp(ctx->last_map_key, "separator") == 0) {
181 ctx->block.no_separator = !val;
186 static int stdin_string(void *context, const unsigned char *val, size_t len) {
187 parser_ctx *ctx = context;
188 if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
189 ctx->block.full_text = i3string_from_markup_with_length((const char *)val, len);
191 if (strcasecmp(ctx->last_map_key, "color") == 0) {
192 sasprintf(&(ctx->block.color), "%.*s", len, val);
194 if (strcasecmp(ctx->last_map_key, "align") == 0) {
195 if (len == strlen("center") && !strncmp((const char *)val, "center", strlen("center"))) {
196 ctx->block.align = ALIGN_CENTER;
197 } else if (len == strlen("right") && !strncmp((const char *)val, "right", strlen("right"))) {
198 ctx->block.align = ALIGN_RIGHT;
200 ctx->block.align = ALIGN_LEFT;
202 } else if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
203 i3String *text = i3string_from_markup_with_length((const char *)val, len);
204 ctx->block.min_width = (uint32_t)predict_text_width(text);
207 if (strcasecmp(ctx->last_map_key, "name") == 0) {
208 char *copy = (char *)malloc(len + 1);
209 strncpy(copy, (const char *)val, len);
211 ctx->block.name = copy;
213 if (strcasecmp(ctx->last_map_key, "instance") == 0) {
214 char *copy = (char *)malloc(len + 1);
215 strncpy(copy, (const char *)val, len);
217 ctx->block.instance = copy;
222 static int stdin_integer(void *context, long long val) {
223 parser_ctx *ctx = context;
224 if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
225 ctx->block.min_width = (uint32_t)val;
227 if (strcasecmp(ctx->last_map_key, "separator_block_width") == 0) {
228 ctx->block.sep_block_width = (uint32_t)val;
234 * When a map is finished, we have an entire status block.
235 * Move it from the parser's context to the statusline buffer.
237 static int stdin_end_map(void *context) {
238 parser_ctx *ctx = context;
239 struct status_block *new_block = smalloc(sizeof(struct status_block));
240 memcpy(new_block, &(ctx->block), sizeof(struct status_block));
241 /* Ensure we have a full_text set, so that when it is missing (or null),
242 * i3bar doesn’t crash and the user gets an annoying message. */
243 if (!new_block->full_text)
244 new_block->full_text = i3string_from_utf8("SPEC VIOLATION: full_text is NULL!");
245 if (new_block->urgent)
246 ctx->has_urgent = true;
247 TAILQ_INSERT_TAIL(&statusline_buffer, new_block, blocks);
252 * When an array is finished, we have an entire statusline.
253 * Copy it from the buffer to the actual statusline.
255 static int stdin_end_array(void *context) {
256 DLOG("copying statusline_buffer to statusline_head\n");
257 clear_statusline(&statusline_head, true);
258 copy_statusline(&statusline_buffer, &statusline_head);
260 DLOG("dumping statusline:\n");
261 struct status_block *current;
262 TAILQ_FOREACH(current, &statusline_head, blocks) {
263 DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
264 DLOG("color = %s\n", current->color);
266 DLOG("end of dump\n");
271 * Helper function to read stdin
273 * Returns NULL on EOF.
276 static unsigned char *get_buffer(ev_io *watcher, int *ret_buffer_len) {
277 int fd = watcher->fd;
280 int buffer_len = STDIN_CHUNK_SIZE;
281 unsigned char *buffer = smalloc(buffer_len + 1);
284 n = read(fd, buffer + rec, buffer_len - rec);
286 if (errno == EAGAIN) {
290 ELOG("read() failed!: %s\n", strerror(errno));
294 ELOG("stdin: received EOF\n");
295 *ret_buffer_len = -1;
300 if (rec == buffer_len) {
301 buffer_len += STDIN_CHUNK_SIZE;
302 buffer = srealloc(buffer, buffer_len);
305 if (*buffer == '\0') {
309 *ret_buffer_len = rec;
313 static void read_flat_input(char *buffer, int length) {
314 struct status_block *first = TAILQ_FIRST(&statusline_head);
315 /* Clear the old buffer if any. */
316 I3STRING_FREE(first->full_text);
317 /* Remove the trailing newline and terminate the string at the same
319 if (buffer[length - 1] == '\n' || buffer[length - 1] == '\r')
320 buffer[length - 1] = '\0';
322 buffer[length] = '\0';
323 first->full_text = i3string_from_markup(buffer);
326 static bool read_json_input(unsigned char *input, int length) {
327 yajl_status status = yajl_parse(parser, input, length);
328 bool has_urgent = false;
329 if (status != yajl_status_ok) {
330 char *message = (char *)yajl_get_error(parser, 0, input, length);
332 /* strip the newline yajl adds to the error message */
333 if (message[strlen(message) - 1] == '\n')
334 message[strlen(message) - 1] = '\0';
336 fprintf(stderr, "[i3bar] Could not parse JSON input (code = %d, message = %s): %.*s\n",
337 status, message, length, input);
339 set_statusline_error("Could not parse JSON (%s)", message);
340 yajl_free_error(parser, (unsigned char *)message);
342 } else if (parser_context.has_urgent) {
349 * Callbalk for stdin. We read a line from stdin and store the result
353 void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
355 unsigned char *buffer = get_buffer(watcher, &rec);
358 bool has_urgent = false;
359 if (child.version > 0) {
360 has_urgent = read_json_input(buffer, rec);
362 read_flat_input((char *)buffer, rec);
365 draw_bars(has_urgent);
369 * Callbalk for stdin first line. We read the first line to detect
370 * whether this is JSON or plain text
373 void stdin_io_first_line_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
375 unsigned char *buffer = get_buffer(watcher, &rec);
378 DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
379 /* Detect whether this is JSON or plain text. */
380 unsigned int consumed = 0;
381 /* At the moment, we don’t care for the version. This might change
382 * in the future, but for now, we just discard it. */
383 parse_json_header(&child, buffer, rec, &consumed);
384 if (child.version > 0) {
385 /* If hide-on-modifier is set, we start of by sending the
386 * child a SIGSTOP, because the bars aren't mapped at start */
387 if (config.hide_on_modifier) {
390 draw_bars(read_json_input(buffer + consumed, rec - consumed));
392 /* In case of plaintext, we just add a single block and change its
393 * full_text pointer later. */
394 struct status_block *new_block = scalloc(sizeof(struct status_block));
395 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
396 read_flat_input((char *)buffer, rec);
399 ev_io_stop(main_loop, stdin_io);
400 ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
401 ev_io_start(main_loop, stdin_io);
405 * We received a SIGCHLD, meaning, that the child process terminated.
406 * We simply free the respective data structures and don't care for input
410 void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
411 int exit_status = WEXITSTATUS(watcher->rstatus);
413 ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
417 /* this error is most likely caused by a user giving a nonexecutable or
418 * nonexistent file, so we will handle those cases separately. */
419 if (exit_status == 126)
420 set_statusline_error("status_command is not executable (exit %d)", exit_status);
421 else if (exit_status == 127)
422 set_statusline_error("status_command not found or is missing a library dependency (exit %d)", exit_status);
424 set_statusline_error("status_command process exited unexpectedly (exit %d)", exit_status);
430 void child_write_output(void) {
431 if (child.click_events) {
432 const unsigned char *output;
435 yajl_gen_get_buf(gen, &output, &size);
436 write(child_stdin, output, size);
437 write(child_stdin, "\n", 1);
443 * Start a child process with the specified command and reroute stdin.
444 * We actually start a $SHELL to execute the command so we don't have to care
445 * about arguments and such.
447 * If `command' is NULL, such as in the case when no `status_command' is given
448 * in the bar config, no child will be started.
451 void start_child(char *command) {
455 /* Allocate a yajl parser which will be used to parse stdin. */
456 static yajl_callbacks callbacks = {
457 .yajl_boolean = stdin_boolean,
458 .yajl_integer = stdin_integer,
459 .yajl_string = stdin_string,
460 .yajl_start_map = stdin_start_map,
461 .yajl_map_key = stdin_map_key,
462 .yajl_end_map = stdin_end_map,
463 .yajl_start_array = stdin_start_array,
464 .yajl_end_array = stdin_end_array,
466 parser = yajl_alloc(&callbacks, NULL, &parser_context);
468 gen = yajl_gen_alloc(NULL);
470 int pipe_in[2]; /* pipe we read from */
471 int pipe_out[2]; /* pipe we write to */
473 if (pipe(pipe_in) == -1)
474 err(EXIT_FAILURE, "pipe(pipe_in)");
475 if (pipe(pipe_out) == -1)
476 err(EXIT_FAILURE, "pipe(pipe_out)");
481 ELOG("Couldn't fork(): %s\n", strerror(errno));
484 /* Child-process. Reroute streams and start shell */
489 dup2(pipe_in[1], STDOUT_FILENO);
490 dup2(pipe_out[0], STDIN_FILENO);
492 setpgid(child.pid, 0);
493 execl(_PATH_BSHELL, _PATH_BSHELL, "-c", command, (char *)NULL);
496 /* Parent-process. Reroute streams */
501 dup2(pipe_in[0], STDIN_FILENO);
502 child_stdin = pipe_out[1];
507 /* We set O_NONBLOCK because blocking is evil in event-driven software */
508 fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
510 stdin_io = smalloc(sizeof(ev_io));
511 ev_io_init(stdin_io, &stdin_io_first_line_cb, STDIN_FILENO, EV_READ);
512 ev_io_start(main_loop, stdin_io);
514 /* We must cleanup, if the child unexpectedly terminates */
515 child_sig = smalloc(sizeof(ev_child));
516 ev_child_init(child_sig, &child_sig_cb, child.pid, 0);
517 ev_child_start(main_loop, child_sig);
519 atexit(kill_child_at_exit);
522 void child_click_events_initialize(void) {
523 if (!child.click_events_init) {
524 yajl_gen_array_open(gen);
525 child_write_output();
526 child.click_events_init = true;
530 void child_click_events_key(const char *key) {
531 yajl_gen_string(gen, (const unsigned char *)key, strlen(key));
535 * Generates a click event, if enabled.
538 void send_block_clicked(int button, const char *name, const char *instance, int x, int y) {
539 if (!child.click_events) {
543 child_click_events_initialize();
545 yajl_gen_map_open(gen);
548 child_click_events_key("name");
549 yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
553 child_click_events_key("instance");
554 yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
557 child_click_events_key("button");
558 yajl_gen_integer(gen, button);
560 child_click_events_key("x");
561 yajl_gen_integer(gen, x);
563 child_click_events_key("y");
564 yajl_gen_integer(gen, y);
566 yajl_gen_map_close(gen);
567 child_write_output();
571 * kill()s the child process (if any). Called when exit()ing.
574 void kill_child_at_exit(void) {
576 if (child.cont_signal > 0 && child.stopped)
577 killpg(child.pid, child.cont_signal);
578 killpg(child.pid, SIGTERM);
583 * kill()s the child process (if existent) and closes and
584 * free()s the stdin- and SIGCHLD-watchers
587 void kill_child(void) {
589 if (child.cont_signal > 0 && child.stopped)
590 killpg(child.pid, child.cont_signal);
591 killpg(child.pid, SIGTERM);
593 waitpid(child.pid, &status, 0);
599 * Sends a SIGSTOP to the child process (if existent)
602 void stop_child(void) {
603 if (child.stop_signal > 0 && !child.stopped) {
604 child.stopped = true;
605 killpg(child.pid, child.stop_signal);
610 * Sends a SIGCONT to the child process (if existent)
613 void cont_child(void) {
614 if (child.cont_signal > 0 && child.stopped) {
615 child.stopped = false;
616 killpg(child.pid, child.cont_signal);
621 * Whether or not the child want click events
624 bool child_want_click_events(void) {
625 return child.click_events;