372 lines
10 KiB
C
372 lines
10 KiB
C
/*
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* vim:ts=4:sw=4:expandtab
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*
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* i3bar - an xcb-based status- and ws-bar for i3
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* © 2010-2012 Axel Wagner and contributors (see also: LICENSE)
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*
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* child.c: Getting Input for the statusline
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*
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*/
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <string.h>
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#include <errno.h>
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#include <err.h>
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#include <ev.h>
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#include <yajl/yajl_common.h>
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#include <yajl/yajl_parse.h>
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#include <yajl/yajl_version.h>
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#include "common.h"
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/* Global variables for child_*() */
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pid_t child_pid;
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/* stdin- and sigchild-watchers */
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ev_io *stdin_io;
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ev_child *child_sig;
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/* JSON parser for stdin */
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bool first_line = true;
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bool plaintext = false;
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yajl_callbacks callbacks;
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yajl_handle parser;
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typedef struct parser_ctx {
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/* A copy of the last JSON map key. */
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char *last_map_key;
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/* The current block. Will be filled, then copied and put into the list of
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* blocks. */
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struct status_block block;
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} parser_ctx;
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parser_ctx parser_context;
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/* The buffer statusline points to */
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struct statusline_head statusline_head = TAILQ_HEAD_INITIALIZER(statusline_head);
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char *statusline_buffer = NULL;
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/*
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* Stop and free() the stdin- and sigchild-watchers
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*
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*/
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void cleanup(void) {
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if (stdin_io != NULL) {
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ev_io_stop(main_loop, stdin_io);
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FREE(stdin_io);
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FREE(statusline_buffer);
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/* statusline pointed to memory within statusline_buffer */
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statusline = NULL;
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}
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if (child_sig != NULL) {
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ev_child_stop(main_loop, child_sig);
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FREE(child_sig);
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}
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}
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/*
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* The start of a new array is the start of a new status line, so we clear all
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* previous entries.
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*
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*/
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static int stdin_start_array(void *context) {
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struct status_block *first;
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while (!TAILQ_EMPTY(&statusline_head)) {
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first = TAILQ_FIRST(&statusline_head);
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I3STRING_FREE(first->full_text);
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FREE(first->color);
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TAILQ_REMOVE(&statusline_head, first, blocks);
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free(first);
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}
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return 1;
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}
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/*
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* The start of a map is the start of a single block of the status line.
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*
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*/
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static int stdin_start_map(void *context) {
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parser_ctx *ctx = context;
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memset(&(ctx->block), '\0', sizeof(struct status_block));
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return 1;
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}
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#if YAJL_MAJOR >= 2
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static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
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#else
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static int stdin_map_key(void *context, const unsigned char *key, unsigned int len) {
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#endif
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parser_ctx *ctx = context;
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FREE(ctx->last_map_key);
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sasprintf(&(ctx->last_map_key), "%.*s", len, key);
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return 1;
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}
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#if YAJL_MAJOR >= 2
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static int stdin_string(void *context, const unsigned char *val, size_t len) {
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#else
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static int stdin_string(void *context, const unsigned char *val, unsigned int len) {
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#endif
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parser_ctx *ctx = context;
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if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
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ctx->block.full_text = i3string_from_utf8_with_length((const char *)val, len);
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}
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if (strcasecmp(ctx->last_map_key, "color") == 0) {
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sasprintf(&(ctx->block.color), "%.*s", len, val);
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}
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return 1;
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}
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static int stdin_end_map(void *context) {
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parser_ctx *ctx = context;
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struct status_block *new_block = smalloc(sizeof(struct status_block));
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memcpy(new_block, &(ctx->block), sizeof(struct status_block));
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/* Ensure we have a full_text set, so that when it is missing (or null),
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* i3bar doesn’t crash and the user gets an annoying message. */
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if (!new_block->full_text)
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new_block->full_text = i3string_from_utf8("SPEC VIOLATION (null)");
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TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
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return 1;
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}
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static int stdin_end_array(void *context) {
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DLOG("dumping statusline:\n");
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struct status_block *current;
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TAILQ_FOREACH(current, &statusline_head, blocks) {
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DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
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DLOG("color = %s\n", current->color);
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}
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DLOG("end of dump\n");
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return 1;
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}
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/*
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* Callbalk for stdin. We read a line from stdin and store the result
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* in statusline
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*
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*/
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void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
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int fd = watcher->fd;
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int n = 0;
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int rec = 0;
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int buffer_len = STDIN_CHUNK_SIZE;
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unsigned char *buffer = smalloc(buffer_len+1);
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buffer[0] = '\0';
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while(1) {
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n = read(fd, buffer + rec, buffer_len - rec);
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if (n == -1) {
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if (errno == EAGAIN) {
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/* finish up */
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break;
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}
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ELOG("read() failed!: %s\n", strerror(errno));
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exit(EXIT_FAILURE);
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}
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if (n == 0) {
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/* end of file, kill the watcher */
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ELOG("stdin: received EOF\n");
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cleanup();
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draw_bars();
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return;
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}
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rec += n;
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if (rec == buffer_len) {
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buffer_len += STDIN_CHUNK_SIZE;
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buffer = srealloc(buffer, buffer_len);
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}
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}
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if (*buffer == '\0') {
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FREE(buffer);
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return;
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}
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unsigned char *json_input = buffer;
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if (first_line) {
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DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
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/* Detect whether this is JSON or plain text. */
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unsigned int consumed = 0;
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/* At the moment, we don’t care for the version. This might change
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* in the future, but for now, we just discard it. */
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plaintext = (determine_json_version(buffer, buffer_len, &consumed) == -1);
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if (plaintext) {
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/* In case of plaintext, we just add a single block and change its
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* full_text pointer later. */
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struct status_block *new_block = scalloc(sizeof(struct status_block));
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TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
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} else {
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json_input += consumed;
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rec -= consumed;
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}
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first_line = false;
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}
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if (!plaintext) {
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yajl_status status = yajl_parse(parser, json_input, rec);
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#if YAJL_MAJOR >= 2
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if (status != yajl_status_ok) {
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#else
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if (status != yajl_status_ok && status != yajl_status_insufficient_data) {
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#endif
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fprintf(stderr, "[i3bar] Could not parse JSON input (code %d): %.*s\n",
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status, rec, json_input);
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}
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} else {
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struct status_block *first = TAILQ_FIRST(&statusline_head);
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/* Clear the old buffer if any. */
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I3STRING_FREE(first->full_text);
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/* Remove the trailing newline and terminate the string at the same
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* time. */
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if (buffer[rec-1] == '\n' || buffer[rec-1] == '\r')
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buffer[rec-1] = '\0';
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else buffer[rec] = '\0';
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first->full_text = i3string_from_utf8((const char *)buffer);
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}
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free(buffer);
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draw_bars();
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}
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/*
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* We received a sigchild, meaning, that the child-process terminated.
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* We simply free the respective data-structures and don't care for input
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* anymore
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*
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*/
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void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
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ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
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child_pid,
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watcher->rstatus);
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cleanup();
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}
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/*
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* Start a child-process with the specified command and reroute stdin.
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* We actually start a $SHELL to execute the command so we don't have to care
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* about arguments and such
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*
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*/
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void start_child(char *command) {
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/* Allocate a yajl parser which will be used to parse stdin. */
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memset(&callbacks, '\0', sizeof(yajl_callbacks));
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callbacks.yajl_map_key = stdin_map_key;
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callbacks.yajl_string = stdin_string;
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callbacks.yajl_start_array = stdin_start_array;
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callbacks.yajl_end_array = stdin_end_array;
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callbacks.yajl_start_map = stdin_start_map;
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callbacks.yajl_end_map = stdin_end_map;
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#if YAJL_MAJOR < 2
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yajl_parser_config parse_conf = { 0, 0 };
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parser = yajl_alloc(&callbacks, &parse_conf, NULL, (void*)&parser_context);
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#else
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parser = yajl_alloc(&callbacks, NULL, &parser_context);
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#endif
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child_pid = 0;
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if (command != NULL) {
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int fd[2];
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if (pipe(fd) == -1)
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err(EXIT_FAILURE, "pipe(fd)");
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child_pid = fork();
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switch (child_pid) {
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case -1:
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ELOG("Couldn't fork(): %s\n", strerror(errno));
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exit(EXIT_FAILURE);
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case 0:
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/* Child-process. Reroute stdout and start shell */
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close(fd[0]);
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dup2(fd[1], STDOUT_FILENO);
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static const char *shell = NULL;
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if ((shell = getenv("SHELL")) == NULL)
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shell = "/bin/sh";
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execl(shell, shell, "-c", command, (char*) NULL);
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return;
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default:
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/* Parent-process. Rerout stdin */
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close(fd[1]);
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dup2(fd[0], STDIN_FILENO);
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/* If hide-on-modifier is set, we start of by sending the
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* child a SIGSTOP, because the bars aren't mapped at start */
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if (config.hide_on_modifier) {
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stop_child();
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}
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break;
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}
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}
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/* We set O_NONBLOCK because blocking is evil in event-driven software */
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fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
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stdin_io = smalloc(sizeof(ev_io));
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ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
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ev_io_start(main_loop, stdin_io);
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/* We must cleanup, if the child unexpectedly terminates */
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child_sig = smalloc(sizeof(ev_child));
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ev_child_init(child_sig, &child_sig_cb, child_pid, 0);
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ev_child_start(main_loop, child_sig);
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atexit(kill_child_at_exit);
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}
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/*
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* kill()s the child-process (if any). Called when exit()ing.
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*
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*/
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void kill_child_at_exit(void) {
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if (child_pid != 0) {
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kill(child_pid, SIGCONT);
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kill(child_pid, SIGTERM);
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}
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}
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/*
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* kill()s the child-process (if existent) and closes and
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* free()s the stdin- and sigchild-watchers
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*
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*/
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void kill_child(void) {
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if (child_pid != 0) {
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kill(child_pid, SIGCONT);
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kill(child_pid, SIGTERM);
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int status;
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waitpid(child_pid, &status, 0);
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child_pid = 0;
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cleanup();
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}
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}
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/*
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* Sends a SIGSTOP to the child-process (if existent)
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*
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*/
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void stop_child(void) {
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if (child_pid != 0) {
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kill(child_pid, SIGSTOP);
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}
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}
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/*
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* Sends a SIGCONT to the child-process (if existent)
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*
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*/
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void cont_child(void) {
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if (child_pid != 0) {
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kill(child_pid, SIGCONT);
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}
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}
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