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 /* A copy of the last JSON map key. */
42 /* The current block. Will be filled, then copied and put into the list of
44 struct status_block block;
47 parser_ctx parser_context;
49 /* The buffer statusline points to */
50 struct statusline_head statusline_head = TAILQ_HEAD_INITIALIZER(statusline_head);
51 char *statusline_buffer = NULL;
54 * Stop and free() the stdin- and sigchild-watchers
58 if (stdin_io != NULL) {
59 ev_io_stop(main_loop, stdin_io);
61 FREE(statusline_buffer);
62 /* statusline pointed to memory within statusline_buffer */
66 if (child_sig != NULL) {
67 ev_child_stop(main_loop, child_sig);
71 memset(&child, 0, sizeof(i3bar_child));
75 * The start of a new array is the start of a new status line, so we clear all
79 static int stdin_start_array(void *context) {
80 struct status_block *first;
81 while (!TAILQ_EMPTY(&statusline_head)) {
82 first = TAILQ_FIRST(&statusline_head);
83 I3STRING_FREE(first->full_text);
85 TAILQ_REMOVE(&statusline_head, first, blocks);
92 * The start of a map is the start of a single block of the status line.
95 static int stdin_start_map(void *context) {
96 parser_ctx *ctx = context;
97 memset(&(ctx->block), '\0', sizeof(struct status_block));
102 static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
104 static int stdin_map_key(void *context, const unsigned char *key, unsigned int len) {
106 parser_ctx *ctx = context;
107 FREE(ctx->last_map_key);
108 sasprintf(&(ctx->last_map_key), "%.*s", len, key);
113 static int stdin_string(void *context, const unsigned char *val, size_t len) {
115 static int stdin_string(void *context, const unsigned char *val, unsigned int len) {
117 parser_ctx *ctx = context;
118 if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
119 ctx->block.full_text = i3string_from_utf8_with_length((const char *)val, len);
121 if (strcasecmp(ctx->last_map_key, "color") == 0) {
122 sasprintf(&(ctx->block.color), "%.*s", len, val);
127 static int stdin_end_map(void *context) {
128 parser_ctx *ctx = context;
129 struct status_block *new_block = smalloc(sizeof(struct status_block));
130 memcpy(new_block, &(ctx->block), sizeof(struct status_block));
131 /* Ensure we have a full_text set, so that when it is missing (or null),
132 * i3bar doesn’t crash and the user gets an annoying message. */
133 if (!new_block->full_text)
134 new_block->full_text = i3string_from_utf8("SPEC VIOLATION (null)");
135 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
139 static int stdin_end_array(void *context) {
140 DLOG("dumping statusline:\n");
141 struct status_block *current;
142 TAILQ_FOREACH(current, &statusline_head, blocks) {
143 DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
144 DLOG("color = %s\n", current->color);
146 DLOG("end of dump\n");
151 * Helper function to read stdin
154 static unsigned char *get_buffer(ev_io *watcher, int *ret_buffer_len) {
155 int fd = watcher->fd;
158 int buffer_len = STDIN_CHUNK_SIZE;
159 unsigned char *buffer = smalloc(buffer_len+1);
162 n = read(fd, buffer + rec, buffer_len - rec);
164 if (errno == EAGAIN) {
168 ELOG("read() failed!: %s\n", strerror(errno));
172 /* end of file, kill the watcher */
173 ELOG("stdin: received EOF\n");
176 *ret_buffer_len = -1;
181 if (rec == buffer_len) {
182 buffer_len += STDIN_CHUNK_SIZE;
183 buffer = srealloc(buffer, buffer_len);
186 if (*buffer == '\0') {
190 *ret_buffer_len = rec;
194 static void read_flat_input(char *buffer, int length) {
195 struct status_block *first = TAILQ_FIRST(&statusline_head);
196 /* Clear the old buffer if any. */
197 I3STRING_FREE(first->full_text);
198 /* Remove the trailing newline and terminate the string at the same
200 if (buffer[length-1] == '\n' || buffer[length-1] == '\r')
201 buffer[length-1] = '\0';
202 else buffer[length] = '\0';
203 first->full_text = i3string_from_utf8(buffer);
206 static void read_json_input(unsigned char *input, int length) {
207 yajl_status status = yajl_parse(parser, input, length);
209 if (status != yajl_status_ok) {
211 if (status != yajl_status_ok && status != yajl_status_insufficient_data) {
213 fprintf(stderr, "[i3bar] Could not parse JSON input (code %d): %.*s\n",
214 status, length, input);
219 * Callbalk for stdin. We read a line from stdin and store the result
223 void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
225 unsigned char *buffer = get_buffer(watcher, &rec);
228 if (child.version > 0) {
229 read_json_input(buffer, rec);
231 read_flat_input((char*)buffer, rec);
238 * Callbalk for stdin first line. We read the first line to detect
239 * whether this is JSON or plain text
242 void stdin_io_first_line_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
244 unsigned char *buffer = get_buffer(watcher, &rec);
247 DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
248 /* Detect whether this is JSON or plain text. */
249 unsigned int consumed = 0;
250 /* At the moment, we don’t care for the version. This might change
251 * in the future, but for now, we just discard it. */
252 child.version = determine_json_version(buffer, rec, &consumed);
253 if (child.version > 0) {
254 read_json_input(buffer + consumed, rec - consumed);
256 /* In case of plaintext, we just add a single block and change its
257 * full_text pointer later. */
258 struct status_block *new_block = scalloc(sizeof(struct status_block));
259 TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
260 read_flat_input((char*)buffer, rec);
263 ev_io_stop(main_loop, stdin_io);
264 ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
265 ev_io_start(main_loop, stdin_io);
269 * We received a sigchild, meaning, that the child-process terminated.
270 * We simply free the respective data-structures and don't care for input
274 void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
275 ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
282 * Start a child-process with the specified command and reroute stdin.
283 * We actually start a $SHELL to execute the command so we don't have to care
284 * about arguments and such
287 void start_child(char *command) {
288 /* Allocate a yajl parser which will be used to parse stdin. */
289 memset(&callbacks, '\0', sizeof(yajl_callbacks));
290 callbacks.yajl_map_key = stdin_map_key;
291 callbacks.yajl_string = stdin_string;
292 callbacks.yajl_start_array = stdin_start_array;
293 callbacks.yajl_end_array = stdin_end_array;
294 callbacks.yajl_start_map = stdin_start_map;
295 callbacks.yajl_end_map = stdin_end_map;
297 yajl_parser_config parse_conf = { 0, 0 };
299 parser = yajl_alloc(&callbacks, &parse_conf, NULL, (void*)&parser_context);
301 parser = yajl_alloc(&callbacks, NULL, &parser_context);
304 if (command != NULL) {
307 err(EXIT_FAILURE, "pipe(fd)");
312 ELOG("Couldn't fork(): %s\n", strerror(errno));
315 /* Child-process. Reroute stdout and start shell */
318 dup2(fd[1], STDOUT_FILENO);
320 static const char *shell = NULL;
322 if ((shell = getenv("SHELL")) == NULL)
325 execl(shell, shell, "-c", command, (char*) NULL);
328 /* Parent-process. Rerout stdin */
331 dup2(fd[0], STDIN_FILENO);
333 /* If hide-on-modifier is set, we start of by sending the
334 * child a SIGSTOP, because the bars aren't mapped at start */
335 if (config.hide_on_modifier) {
343 /* We set O_NONBLOCK because blocking is evil in event-driven software */
344 fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
346 stdin_io = smalloc(sizeof(ev_io));
347 ev_io_init(stdin_io, &stdin_io_first_line_cb, STDIN_FILENO, EV_READ);
348 ev_io_start(main_loop, stdin_io);
350 /* We must cleanup, if the child unexpectedly terminates */
351 child_sig = smalloc(sizeof(ev_child));
352 ev_child_init(child_sig, &child_sig_cb, child.pid, 0);
353 ev_child_start(main_loop, child_sig);
355 atexit(kill_child_at_exit);
359 * kill()s the child-process (if any). Called when exit()ing.
362 void kill_child_at_exit(void) {
364 kill(child.pid, SIGCONT);
365 kill(child.pid, SIGTERM);
370 * kill()s the child-process (if existent) and closes and
371 * free()s the stdin- and sigchild-watchers
374 void kill_child(void) {
376 kill(child.pid, SIGCONT);
377 kill(child.pid, SIGTERM);
379 waitpid(child.pid, &status, 0);
385 * Sends a SIGSTOP to the child-process (if existent)
388 void stop_child(void) {
390 kill(child.pid, SIGSTOP);
395 * Sends a SIGCONT to the child-process (if existent)
398 void cont_child(void) {
400 kill(child.pid, SIGCONT);