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_*() */
31 i3bar_child child = { 0 };
33 /* stdin- and sigchild-watchers */
37 /* JSON parser for stdin */
38 yajl_callbacks callbacks;
41 /* JSON generator for stdout */
44 typedef struct parser_ctx {
45 /* True if one of the parsed blocks was urgent */
48 /* A copy of the last JSON map key. */
51 /* The current block. Will be filled, then copied and put into the list of
53 struct status_block block;
56 parser_ctx parser_context;
58 /* The buffer statusline points to */
59 struct statusline_head statusline_head = TAILQ_HEAD_INITIALIZER(statusline_head);
60 char *statusline_buffer = NULL;
65 * Clears all blocks from the statusline structure in memory and frees their
66 * associated resources.
68 static void clear_status_blocks() {
69 struct status_block *first;
70 while (!TAILQ_EMPTY(&statusline_head)) {
71 first = TAILQ_FIRST(&statusline_head);
72 I3STRING_FREE(first->full_text);
73 TAILQ_REMOVE(&statusline_head, first, blocks);
79 * Replaces the statusline in memory with an error message. Pass a format
80 * string and format parameters as you would in `printf'. The next time
81 * `draw_bars' is called, the error message text will be drawn on the bar in
82 * the space allocated for the statusline.
85 /* forward function declaration is needed to add __attribute__ mechanism which
86 * helps the compiler understand we are defining a printf wrapper */
87 static void set_statusline_error(const char *format, ...) __attribute__ ((format (printf, 1, 2)));
89 static void set_statusline_error(const char *format, ...) {
90 clear_status_blocks();
94 va_start(args, format);
95 vasprintf(&message, format, args);
97 struct status_block *err_block = scalloc(sizeof(struct status_block));
98 err_block->full_text = i3string_from_utf8("Error: ");
99 err_block->name = "error";
100 err_block->color = "red";
101 err_block->no_separator = true;
103 struct status_block *message_block = scalloc(sizeof(struct status_block));
104 message_block->full_text = i3string_from_utf8(message);
105 message_block->name = "error_message";
106 message_block->color = "red";
107 message_block->no_separator = true;
109 TAILQ_INSERT_HEAD(&statusline_head, err_block, blocks);
110 TAILQ_INSERT_TAIL(&statusline_head, message_block, blocks);
117 * Stop and free() the stdin- and sigchild-watchers
121 if (stdin_io != NULL) {
122 ev_io_stop(main_loop, stdin_io);
124 FREE(statusline_buffer);
125 /* statusline pointed to memory within statusline_buffer */
129 if (child_sig != NULL) {
130 ev_child_stop(main_loop, child_sig);
134 memset(&child, 0, sizeof(i3bar_child));
138 * The start of a new array is the start of a new status line, so we clear all
142 static int stdin_start_array(void *context) {
143 struct status_block *first;
144 while (!TAILQ_EMPTY(&statusline_head)) {
145 first = TAILQ_FIRST(&statusline_head);
146 I3STRING_FREE(first->full_text);
149 FREE(first->instance);
150 TAILQ_REMOVE(&statusline_head, first, blocks);
157 * The start of a map is the start of a single block of the status line.
160 static int stdin_start_map(void *context) {
161 parser_ctx *ctx = context;
162 memset(&(ctx->block), '\0', sizeof(struct status_block));
164 /* Default width of the separator block. */
165 ctx->block.sep_block_width = 9;
171 static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
173 static int stdin_map_key(void *context, const unsigned char *key, unsigned int len) {
175 parser_ctx *ctx = context;
176 FREE(ctx->last_map_key);
177 sasprintf(&(ctx->last_map_key), "%.*s", len, key);
181 static int stdin_boolean(void *context, int val) {
182 parser_ctx *ctx = context;
183 if (strcasecmp(ctx->last_map_key, "urgent") == 0) {
184 ctx->block.urgent = val;
186 if (strcasecmp(ctx->last_map_key, "separator") == 0) {
187 ctx->block.no_separator = !val;
193 static int stdin_string(void *context, const unsigned char *val, size_t len) {
195 static int stdin_string(void *context, const unsigned char *val, unsigned int len) {
197 parser_ctx *ctx = context;
198 if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
199 ctx->block.full_text = i3string_from_utf8_with_length((const char *)val, len);
201 if (strcasecmp(ctx->last_map_key, "color") == 0) {
202 sasprintf(&(ctx->block.color), "%.*s", len, val);
204 if (strcasecmp(ctx->last_map_key, "align") == 0) {
205 if (len == strlen("left") && !strncmp((const char*)val, "left", strlen("left"))) {
206 ctx->block.align = ALIGN_LEFT;
207 } else if (len == strlen("right") && !strncmp((const char*)val, "right", strlen("right"))) {
208 ctx->block.align = ALIGN_RIGHT;
210 ctx->block.align = ALIGN_CENTER;
212 } else if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
213 i3String *text = i3string_from_utf8_with_length((const char *)val, len);
214 ctx->block.min_width = (uint32_t)predict_text_width(text);
217 if (strcasecmp(ctx->last_map_key, "name") == 0) {
218 char *copy = (char*)malloc(len+1);
219 strncpy(copy, (const char *)val, len);
221 ctx->block.name = copy;
223 if (strcasecmp(ctx->last_map_key, "instance") == 0) {
224 char *copy = (char*)malloc(len+1);
225 strncpy(copy, (const char *)val, len);
227 ctx->block.instance = copy;
233 static int stdin_integer(void *context, long long val) {
235 static int stdin_integer(void *context, long val) {
237 parser_ctx *ctx = context;
238 if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
239 ctx->block.min_width = (uint32_t)val;
241 if (strcasecmp(ctx->last_map_key, "separator_block_width") == 0) {
242 ctx->block.sep_block_width = (uint32_t)val;
247 static int stdin_end_map(void *context) {
248 parser_ctx *ctx = context;
249 struct status_block *new_block = smalloc(sizeof(struct status_block));
250 memcpy(new_block, &(ctx->block), sizeof(struct status_block));
251 /* Ensure we have a full_text set, so that when it is missing (or null),
252 * i3bar doesn’t crash and the user gets an annoying message. */
253 if (!new_block->full_text)
254 new_block->full_text = i3string_from_utf8("SPEC VIOLATION (null)");
255 if (new_block->urgent)
256 ctx->has_urgent = true;
257 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
261 static int stdin_end_array(void *context) {
262 DLOG("dumping statusline:\n");
263 struct status_block *current;
264 TAILQ_FOREACH(current, &statusline_head, blocks) {
265 DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
266 DLOG("color = %s\n", current->color);
268 DLOG("end of dump\n");
273 * Helper function to read stdin
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 /* end of file, kill the watcher */
295 ELOG("stdin: received EOF\n");
297 *ret_buffer_len = -1;
302 if (rec == buffer_len) {
303 buffer_len += STDIN_CHUNK_SIZE;
304 buffer = srealloc(buffer, buffer_len);
307 if (*buffer == '\0') {
311 *ret_buffer_len = rec;
315 static void read_flat_input(char *buffer, int length) {
316 struct status_block *first = TAILQ_FIRST(&statusline_head);
317 /* Clear the old buffer if any. */
318 I3STRING_FREE(first->full_text);
319 /* Remove the trailing newline and terminate the string at the same
321 if (buffer[length-1] == '\n' || buffer[length-1] == '\r')
322 buffer[length-1] = '\0';
323 else buffer[length] = '\0';
324 first->full_text = i3string_from_utf8(buffer);
327 static bool read_json_input(unsigned char *input, int length) {
328 yajl_status status = yajl_parse(parser, input, length);
329 bool has_urgent = false;
331 if (status != yajl_status_ok) {
333 if (status != yajl_status_ok && status != yajl_status_insufficient_data) {
335 char *message = (char *)yajl_get_error(parser, 0, input, length);
337 /* strip the newline yajl adds to the error message */
338 if (message[strlen(message) - 1] == '\n')
339 message[strlen(message) - 1] = '\0';
341 fprintf(stderr, "[i3bar] Could not parse JSON input (code = %d, message = %s): %.*s\n",
342 status, message, length, input);
344 set_statusline_error("Could not parse JSON (%s)", message);
345 yajl_free_error(parser, (unsigned char*)message);
347 } else if (parser_context.has_urgent) {
354 * Callbalk for stdin. We read a line from stdin and store the result
358 void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
360 unsigned char *buffer = get_buffer(watcher, &rec);
363 bool has_urgent = false;
364 if (child.version > 0) {
365 has_urgent = read_json_input(buffer, rec);
367 read_flat_input((char*)buffer, rec);
370 draw_bars(has_urgent);
374 * Callbalk for stdin first line. We read the first line to detect
375 * whether this is JSON or plain text
378 void stdin_io_first_line_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
380 unsigned char *buffer = get_buffer(watcher, &rec);
383 DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
384 /* Detect whether this is JSON or plain text. */
385 unsigned int consumed = 0;
386 /* At the moment, we don’t care for the version. This might change
387 * in the future, but for now, we just discard it. */
388 parse_json_header(&child, buffer, rec, &consumed);
389 if (child.version > 0) {
390 /* If hide-on-modifier is set, we start of by sending the
391 * child a SIGSTOP, because the bars aren't mapped at start */
392 if (config.hide_on_modifier) {
395 read_json_input(buffer + consumed, rec - consumed);
397 /* In case of plaintext, we just add a single block and change its
398 * full_text pointer later. */
399 struct status_block *new_block = scalloc(sizeof(struct status_block));
400 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
401 read_flat_input((char*)buffer, rec);
404 ev_io_stop(main_loop, stdin_io);
405 ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
406 ev_io_start(main_loop, stdin_io);
410 * We received a sigchild, meaning, that the child-process terminated.
411 * We simply free the respective data-structures and don't care for input
415 void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
416 int exit_status = WEXITSTATUS(watcher->rstatus);
418 ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
422 /* this error is most likely caused by a user giving a nonexecutable or
423 * nonexistent file, so we will handle those cases separately. */
424 if (exit_status == 126)
425 set_statusline_error("status_command is not executable (exit %d)", exit_status);
426 else if (exit_status == 127)
427 set_statusline_error("status_command not found (exit %d)", exit_status);
429 set_statusline_error("status_command process exited unexpectedly (exit %d)", exit_status);
435 void child_write_output(void) {
436 if (child.click_events) {
437 const unsigned char *output;
443 yajl_gen_get_buf(gen, &output, &size);
444 write(child_stdin, output, size);
445 write(child_stdin, "\n", 1);
451 * Start a child-process with the specified command and reroute stdin.
452 * We actually start a $SHELL to execute the command so we don't have to care
453 * about arguments and such
456 void start_child(char *command) {
457 /* Allocate a yajl parser which will be used to parse stdin. */
458 memset(&callbacks, '\0', sizeof(yajl_callbacks));
459 callbacks.yajl_map_key = stdin_map_key;
460 callbacks.yajl_boolean = stdin_boolean;
461 callbacks.yajl_string = stdin_string;
462 callbacks.yajl_integer = stdin_integer;
463 callbacks.yajl_start_array = stdin_start_array;
464 callbacks.yajl_end_array = stdin_end_array;
465 callbacks.yajl_start_map = stdin_start_map;
466 callbacks.yajl_end_map = stdin_end_map;
468 yajl_parser_config parse_conf = { 0, 0 };
470 parser = yajl_alloc(&callbacks, &parse_conf, NULL, (void*)&parser_context);
472 gen = yajl_gen_alloc(NULL, NULL);
474 parser = yajl_alloc(&callbacks, NULL, &parser_context);
476 gen = yajl_gen_alloc(NULL);
479 if (command != NULL) {
480 int pipe_in[2]; /* pipe we read from */
481 int pipe_out[2]; /* pipe we write to */
483 if (pipe(pipe_in) == -1)
484 err(EXIT_FAILURE, "pipe(pipe_in)");
485 if (pipe(pipe_out) == -1)
486 err(EXIT_FAILURE, "pipe(pipe_out)");
491 ELOG("Couldn't fork(): %s\n", strerror(errno));
494 /* Child-process. Reroute streams and start shell */
499 dup2(pipe_in[1], STDOUT_FILENO);
500 dup2(pipe_out[0], STDIN_FILENO);
502 setpgid(child.pid, 0);
503 execl(_PATH_BSHELL, _PATH_BSHELL, "-c", command, (char*) NULL);
506 /* Parent-process. Reroute streams */
511 dup2(pipe_in[0], STDIN_FILENO);
512 child_stdin = pipe_out[1];
518 /* We set O_NONBLOCK because blocking is evil in event-driven software */
519 fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
521 stdin_io = smalloc(sizeof(ev_io));
522 ev_io_init(stdin_io, &stdin_io_first_line_cb, STDIN_FILENO, EV_READ);
523 ev_io_start(main_loop, stdin_io);
525 /* We must cleanup, if the child unexpectedly terminates */
526 child_sig = smalloc(sizeof(ev_child));
527 ev_child_init(child_sig, &child_sig_cb, child.pid, 0);
528 ev_child_start(main_loop, child_sig);
530 atexit(kill_child_at_exit);
533 void child_click_events_initialize(void) {
534 if (!child.click_events_init) {
535 yajl_gen_array_open(gen);
536 child_write_output();
537 child.click_events_init = true;
541 void child_click_events_key(const char *key) {
542 yajl_gen_string(gen, (const unsigned char *)key, strlen(key));
546 * Generates a click event, if enabled.
549 void send_block_clicked(int button, const char *name, const char *instance, int x, int y) {
550 if (child.click_events) {
551 child_click_events_initialize();
553 yajl_gen_map_open(gen);
556 child_click_events_key("name");
557 yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
561 child_click_events_key("instance");
562 yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
565 child_click_events_key("button");
566 yajl_gen_integer(gen, button);
568 child_click_events_key("x");
569 yajl_gen_integer(gen, x);
571 child_click_events_key("y");
572 yajl_gen_integer(gen, y);
574 yajl_gen_map_close(gen);
575 child_write_output();
580 * kill()s the child-process (if any). Called when exit()ing.
583 void kill_child_at_exit(void) {
585 if (child.cont_signal > 0 && child.stopped)
586 killpg(child.pid, child.cont_signal);
587 killpg(child.pid, SIGTERM);
592 * kill()s the child-process (if existent) and closes and
593 * free()s the stdin- and sigchild-watchers
596 void kill_child(void) {
598 if (child.cont_signal > 0 && child.stopped)
599 killpg(child.pid, child.cont_signal);
600 killpg(child.pid, SIGTERM);
602 waitpid(child.pid, &status, 0);
608 * Sends a SIGSTOP to the child-process (if existent)
611 void stop_child(void) {
612 if (child.stop_signal > 0 && !child.stopped) {
613 child.stopped = true;
614 killpg(child.pid, child.stop_signal);
619 * Sends a SIGCONT to the child-process (if existent)
622 void cont_child(void) {
623 if (child.cont_signal > 0 && child.stopped) {
624 child.stopped = false;
625 killpg(child.pid, child.cont_signal);