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>
21 #include <yajl/yajl_common.h>
22 #include <yajl/yajl_parse.h>
23 #include <yajl/yajl_version.h>
27 /* Global variables for child_*() */
28 i3bar_child child = { 0 };
30 /* stdin- and sigchild-watchers */
34 /* JSON parser for stdin */
35 yajl_callbacks callbacks;
38 typedef struct parser_ctx {
39 /* True if one of the parsed blocks was urgent */
42 /* A copy of the last JSON map key. */
45 /* The current block. Will be filled, then copied and put into the list of
47 struct status_block block;
50 parser_ctx parser_context;
52 /* The buffer statusline points to */
53 struct statusline_head statusline_head = TAILQ_HEAD_INITIALIZER(statusline_head);
54 char *statusline_buffer = NULL;
57 * Stop and free() the stdin- and sigchild-watchers
61 if (stdin_io != NULL) {
62 ev_io_stop(main_loop, stdin_io);
64 FREE(statusline_buffer);
65 /* statusline pointed to memory within statusline_buffer */
69 if (child_sig != NULL) {
70 ev_child_stop(main_loop, child_sig);
74 memset(&child, 0, sizeof(i3bar_child));
78 * The start of a new array is the start of a new status line, so we clear all
82 static int stdin_start_array(void *context) {
83 struct status_block *first;
84 while (!TAILQ_EMPTY(&statusline_head)) {
85 first = TAILQ_FIRST(&statusline_head);
86 I3STRING_FREE(first->full_text);
88 TAILQ_REMOVE(&statusline_head, first, blocks);
95 * The start of a map is the start of a single block of the status line.
98 static int stdin_start_map(void *context) {
99 parser_ctx *ctx = context;
100 memset(&(ctx->block), '\0', sizeof(struct status_block));
105 static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
107 static int stdin_map_key(void *context, const unsigned char *key, unsigned int len) {
109 parser_ctx *ctx = context;
110 FREE(ctx->last_map_key);
111 sasprintf(&(ctx->last_map_key), "%.*s", len, key);
115 static int stdin_boolean(void *context, int val) {
116 parser_ctx *ctx = context;
117 if (strcasecmp(ctx->last_map_key, "urgent") == 0) {
118 ctx->block.urgent = val;
124 static int stdin_string(void *context, const unsigned char *val, size_t len) {
126 static int stdin_string(void *context, const unsigned char *val, unsigned int len) {
128 parser_ctx *ctx = context;
129 if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
130 ctx->block.full_text = i3string_from_utf8_with_length((const char *)val, len);
132 if (strcasecmp(ctx->last_map_key, "color") == 0) {
133 sasprintf(&(ctx->block.color), "%.*s", len, val);
138 static int stdin_end_map(void *context) {
139 parser_ctx *ctx = context;
140 struct status_block *new_block = smalloc(sizeof(struct status_block));
141 memcpy(new_block, &(ctx->block), sizeof(struct status_block));
142 /* Ensure we have a full_text set, so that when it is missing (or null),
143 * i3bar doesn’t crash and the user gets an annoying message. */
144 if (!new_block->full_text)
145 new_block->full_text = i3string_from_utf8("SPEC VIOLATION (null)");
146 if (new_block->urgent)
147 ctx->has_urgent = true;
148 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
152 static int stdin_end_array(void *context) {
153 DLOG("dumping statusline:\n");
154 struct status_block *current;
155 TAILQ_FOREACH(current, &statusline_head, blocks) {
156 DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
157 DLOG("color = %s\n", current->color);
159 DLOG("end of dump\n");
164 * Helper function to read stdin
167 static unsigned char *get_buffer(ev_io *watcher, int *ret_buffer_len) {
168 int fd = watcher->fd;
171 int buffer_len = STDIN_CHUNK_SIZE;
172 unsigned char *buffer = smalloc(buffer_len+1);
175 n = read(fd, buffer + rec, buffer_len - rec);
177 if (errno == EAGAIN) {
181 ELOG("read() failed!: %s\n", strerror(errno));
185 /* end of file, kill the watcher */
186 ELOG("stdin: received EOF\n");
189 *ret_buffer_len = -1;
194 if (rec == buffer_len) {
195 buffer_len += STDIN_CHUNK_SIZE;
196 buffer = srealloc(buffer, buffer_len);
199 if (*buffer == '\0') {
203 *ret_buffer_len = rec;
207 static void read_flat_input(char *buffer, int length) {
208 struct status_block *first = TAILQ_FIRST(&statusline_head);
209 /* Clear the old buffer if any. */
210 I3STRING_FREE(first->full_text);
211 /* Remove the trailing newline and terminate the string at the same
213 if (buffer[length-1] == '\n' || buffer[length-1] == '\r')
214 buffer[length-1] = '\0';
215 else buffer[length] = '\0';
216 first->full_text = i3string_from_utf8(buffer);
219 static bool read_json_input(unsigned char *input, int length) {
220 yajl_status status = yajl_parse(parser, input, length);
221 bool has_urgent = false;
223 if (status != yajl_status_ok) {
225 if (status != yajl_status_ok && status != yajl_status_insufficient_data) {
227 fprintf(stderr, "[i3bar] Could not parse JSON input (code %d): %.*s\n",
228 status, length, input);
229 } else if (parser_context.has_urgent) {
236 * Callbalk for stdin. We read a line from stdin and store the result
240 void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
242 unsigned char *buffer = get_buffer(watcher, &rec);
245 bool has_urgent = false;
246 if (child.version > 0) {
247 has_urgent = read_json_input(buffer, rec);
249 read_flat_input((char*)buffer, rec);
252 draw_bars(has_urgent);
256 * Callbalk for stdin first line. We read the first line to detect
257 * whether this is JSON or plain text
260 void stdin_io_first_line_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
262 unsigned char *buffer = get_buffer(watcher, &rec);
265 DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
266 /* Detect whether this is JSON or plain text. */
267 unsigned int consumed = 0;
268 /* At the moment, we don’t care for the version. This might change
269 * in the future, but for now, we just discard it. */
270 parse_json_header(&child, buffer, rec, &consumed);
271 if (child.version > 0) {
272 /* If hide-on-modifier is set, we start of by sending the
273 * child a SIGSTOP, because the bars aren't mapped at start */
274 if (config.hide_on_modifier) {
277 read_json_input(buffer + consumed, rec - consumed);
279 /* In case of plaintext, we just add a single block and change its
280 * full_text pointer later. */
281 struct status_block *new_block = scalloc(sizeof(struct status_block));
282 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
283 read_flat_input((char*)buffer, rec);
286 ev_io_stop(main_loop, stdin_io);
287 ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
288 ev_io_start(main_loop, stdin_io);
292 * We received a sigchild, meaning, that the child-process terminated.
293 * We simply free the respective data-structures and don't care for input
297 void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
298 ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
305 * Start a child-process with the specified command and reroute stdin.
306 * We actually start a $SHELL to execute the command so we don't have to care
307 * about arguments and such
310 void start_child(char *command) {
311 /* Allocate a yajl parser which will be used to parse stdin. */
312 memset(&callbacks, '\0', sizeof(yajl_callbacks));
313 callbacks.yajl_map_key = stdin_map_key;
314 callbacks.yajl_boolean = stdin_boolean;
315 callbacks.yajl_string = stdin_string;
316 callbacks.yajl_start_array = stdin_start_array;
317 callbacks.yajl_end_array = stdin_end_array;
318 callbacks.yajl_start_map = stdin_start_map;
319 callbacks.yajl_end_map = stdin_end_map;
321 yajl_parser_config parse_conf = { 0, 0 };
323 parser = yajl_alloc(&callbacks, &parse_conf, NULL, (void*)&parser_context);
325 parser = yajl_alloc(&callbacks, NULL, &parser_context);
328 if (command != NULL) {
331 err(EXIT_FAILURE, "pipe(fd)");
336 ELOG("Couldn't fork(): %s\n", strerror(errno));
339 /* Child-process. Reroute stdout and start shell */
342 dup2(fd[1], STDOUT_FILENO);
344 static const char *shell = NULL;
346 if ((shell = getenv("SHELL")) == NULL)
349 execl(shell, shell, "-c", command, (char*) NULL);
352 /* Parent-process. Rerout stdin */
355 dup2(fd[0], STDIN_FILENO);
361 /* We set O_NONBLOCK because blocking is evil in event-driven software */
362 fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
364 stdin_io = smalloc(sizeof(ev_io));
365 ev_io_init(stdin_io, &stdin_io_first_line_cb, STDIN_FILENO, EV_READ);
366 ev_io_start(main_loop, stdin_io);
368 /* We must cleanup, if the child unexpectedly terminates */
369 child_sig = smalloc(sizeof(ev_child));
370 ev_child_init(child_sig, &child_sig_cb, child.pid, 0);
371 ev_child_start(main_loop, child_sig);
373 atexit(kill_child_at_exit);
377 * kill()s the child-process (if any). Called when exit()ing.
380 void kill_child_at_exit(void) {
382 if (child.cont_signal > 0 && child.stopped)
383 kill(child.pid, child.cont_signal);
384 kill(child.pid, SIGTERM);
389 * kill()s the child-process (if existent) and closes and
390 * free()s the stdin- and sigchild-watchers
393 void kill_child(void) {
395 if (child.cont_signal > 0 && child.stopped)
396 kill(child.pid, child.cont_signal);
397 kill(child.pid, SIGTERM);
399 waitpid(child.pid, &status, 0);
405 * Sends a SIGSTOP to the child-process (if existent)
408 void stop_child(void) {
409 if (child.stop_signal > 0 && !child.stopped) {
410 child.stopped = true;
411 kill(child.pid, child.stop_signal);
416 * Sends a SIGCONT to the child-process (if existent)
419 void cont_child(void) {
420 if (child.cont_signal > 0 && child.stopped) {
421 child.stopped = false;
422 kill(child.pid, child.cont_signal);