Genesis commit

1 files changed, 289 insertions, 0 deletions

diff --git a/mstatus.c b/mstatus.c
new file mode 100644
index 0000000..2599db0
--- /dev/null
+++ b/mstatus.c
@@ -0,0 +1,289 @@
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <linux/limits.h>
+#include <paths.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdnoreturn.h>
+#include <signal.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include <X11/Xlib.h>
+
+#define CTOI(x)  ((x) ^ 48)
+
+struct Block {
+	int pos;
+	char *text;
+	bool remove;
+};
+
+bool rflag;
+const char *argv0;
+struct {
+	char *str;
+	size_t len;
+} seperator = {.str = " | ", .len = 3};
+
+static noreturn void
+usage(void)
+{
+	fprintf(stderr, "Usage: %s [-r] [-s seperator]\n", argv0);
+	exit(EXIT_FAILURE);
+}
+
+static noreturn void
+die(const char *s)
+{
+	char *err = strerror(errno);
+	syslog(LOG_ERR, "%s: %s", s, err);
+	fprintf(stderr, "%s: %s: %s\n", argv0, s, err);
+	exit(EXIT_FAILURE);
+}
+
+static void
+xfork(void)
+{
+	pid_t pid = fork();
+	if (pid == -1)
+		die("fork");
+	if (pid != 0)
+		exit(EXIT_SUCCESS);
+}
+
+static void *
+xrealloc(void *ptr, size_t size)
+{
+	void *ret;
+	if (!(ret = realloc(ptr, size)))
+		die("realloc");
+	return ret;
+}
+
+static void
+xfree(char **ptr)
+{
+	free(*ptr);
+	*ptr = NULL;
+}
+
+static void
+write_status(struct Block b)
+{
+	static struct {
+		char **blocks;
+		int count;
+		size_t length;
+	} sb;
+
+	if (b.remove) {
+		if (b.pos > sb.count)
+			return;
+
+		/* b.remove && !b.pos is a special case to remove everything from the bar */
+		if (!b.pos) {
+			for (int i = 0; i < sb.count; i++)
+				free(sb.blocks[i]);
+			sb.count = 0;
+			sb.blocks = xrealloc(sb.blocks, sizeof(char *));
+			goto update_bar;
+		}
+
+		/* If the block is not NULL we free it */
+		if (sb.blocks[--b.pos]) {
+			sb.length -= strlen(sb.blocks[b.pos]);
+			xfree(&sb.blocks[b.pos]);
+		}
+
+		/* If the block is the last one, we resize the bar to remove trailing NULL blocks */
+		if (b.pos + 1 == sb.count) {
+			for (; !sb.blocks[b.pos] && b.pos; b.pos--)
+				sb.count--;
+			sb.blocks = xrealloc(sb.blocks, sizeof(char *) * ++b.pos);
+		}
+		goto update_bar;
+	}
+
+	/* If the position exceeds the space allocated, allocate more blocks */
+	if (b.pos > sb.count) {
+		sb.blocks = xrealloc(sb.blocks, sizeof(char *) * b.pos);
+		/* Make sure to set all the newly allocated blocks to NULL */
+		for (int i = sb.count; i < b.pos; i++)
+			sb.blocks[i] = NULL;
+		sb.count = b.pos;
+	}
+
+	/* If the block is NULL we dont need to bother with strlen and free */
+	if (sb.blocks[--b.pos]) {
+		sb.length -= strlen(sb.blocks[b.pos]);
+		xfree(&sb.blocks[b.pos]);
+	}
+	if (!(sb.blocks[b.pos] = strdup(b.text)))
+		die("strdup");
+	sb.length += strlen(b.text);
+
+	/*
+	 * The buffer to store the text that will be displayed in. It needs space for the text, the
+	 * seperators between the different blocks, the NUL byte at the end, and the right padding
+	 * space.
+	 */
+update_bar:;
+	char buf[sb.length + (sb.count - 1) * seperator.len + 2];
+	memset(buf, '\0', sb.length + 1);
+
+	/* Double for loops so that the seperator isnt printed to the left of the first block */
+	int i;
+	for (i = 0; i < sb.count; i++) {
+		if (sb.blocks[i]) {
+			strcpy(buf, sb.blocks[i]);
+			break;
+		}
+	}
+	for (i++; i < sb.count; i++)
+		if (sb.blocks[i])
+			sprintf(buf, "%s%s%s", buf, seperator.str, sb.blocks[i]);
+	if (rflag)
+		strcat(buf, " ");
+
+	/* Xlib magic to set the DWM status */
+	Display *dpy = XOpenDisplay(NULL);
+	int screen = DefaultScreen(dpy);
+	Window root = RootWindow(dpy, screen);
+	(void) XStoreName(dpy, root, buf);
+	(void) XCloseDisplay(dpy);
+}
+
+static bool
+process(char *line, ssize_t len, struct Block *b)
+{
+	/* For some reason output with newlines can cause performance issues */
+	if (line[--len] == '\n')
+		line[len] = '\0';
+
+	if (*line == '-') {
+		b->remove = true;
+		line++;
+	}
+	else
+		b->remove = false;
+
+	if (!isdigit(*line))
+		b->pos = 1; /* Default position */
+	else {
+		b->pos = 0;
+		while (isdigit(*line))
+			b->pos = b->pos * 10 + CTOI(*line++);
+		if (!b->pos && !b->remove)
+			return false;
+	}
+
+	b->text = line;
+	return true;
+}
+
+static void
+create_fifo(char *fifo_path)
+{
+	char *runtime_dir = getenv("XDG_RUNTIME_DIR");
+	if (runtime_dir) {
+		size_t end = strlen(runtime_dir) - 1;
+		if (runtime_dir[end] == '/')
+			runtime_dir[end] = '\0';
+		sprintf(fifo_path, "%s/%s.pipe", runtime_dir, argv0);
+	}
+	else
+		sprintf(fifo_path, _PATH_VARRUN "user/%d/%s.pipe", getuid(), argv0);
+
+	umask(0);
+
+create_fifo:
+	if (mkfifo(fifo_path, DEFFILEMODE) == -1) {
+		if (errno == EEXIST) {
+			if (unlink(fifo_path) == -1)
+				die("unlink");
+			goto create_fifo;
+		}
+		else
+			die("mkfifo");
+	}
+
+	syslog(LOG_INFO, "Created input FIFO '%s'", fifo_path);
+}
+
+static void
+daemonize(void)
+{
+	xfork();
+	if (setsid() == -1)
+		die("setsid");
+
+	(void) signal(SIGCHLD, SIG_IGN);
+	xfork();
+
+	(void) chdir("/");
+	(void) close(STDIN_FILENO);
+	(void) close(STDOUT_FILENO);
+	(void) close(STDERR_FILENO);
+
+	stdin = fopen(_PATH_DEVNULL, "r");
+	stdout = fopen(_PATH_DEVNULL, "w+");
+	stderr = fopen(_PATH_DEVNULL, "w+");
+
+	syslog(LOG_INFO, "Daemonized '%s'", argv0);
+}
+
+int
+main(int argc, char **argv)
+{
+	(void) argc;
+	argv0 = argv[0];
+
+	int opt;
+	while ((opt = getopt(argc, argv, ":rs:")) != -1) {
+		switch (opt) {
+		case 'r':
+			rflag = true;
+			break;
+		case 's':
+			seperator.str = optarg;
+			seperator.len = strlen(optarg);
+			break;
+		default:
+			usage();
+		}
+	}
+
+	openlog(argv0, LOG_PID | LOG_CONS, LOG_DAEMON);
+	char fifo_path[PATH_MAX];
+	create_fifo(fifo_path);
+	daemonize();
+
+	char *line = NULL;
+	size_t len = 0;
+	while (true) {
+		FILE *fp;
+		if (!(fp = fopen(fifo_path, "r")))
+			die("fopen");
+
+		ssize_t nr;
+		while ((nr = getline(&line, &len, fp)) != -1) {
+			syslog(LOG_INFO, "Recieved command '%s'", line);
+			struct Block b;
+			if (!process(line, nr, &b))
+				continue;
+			write_status(b);
+		}
+		if (ferror(fp))
+			die("getline");
+
+		(void) fclose(fp);
+	}
+	/* NOTREACHED */
+}