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	lchat: exclude filter from input tail pipe - lchat - A line oriented chat front…
	git clone git://git.suckless.org/lchat
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	---
	commit e5371dc7ca278ac80852f30b699ae3f0ae8627bf
	parent 5d78aec7398254c86ce90cb53d750af437f12a75
	Author: Jan Klemkow <[email protected]>
	Date: Wed, 22 Feb 2017 21:08:33 +0100

	lchat: exclude filter from input tail pipe

	This avoids a conflict between .bellmatch and .filter.
	Both programs get the same raw input from tail now.

	Diffstat:
	M lchat.c \| 83 ++++++++++++++++++++++++++++-…

	1 file changed, 77 insertions(+), 6 deletions(-)
	---
	diff --git a/lchat.c b/lchat.c
	@@ -119,6 +119,45 @@ line_output(struct slackline sl, char file)
	}

	static void
	+fork_filter(int read, int write)
	+{
	+ int fds_read[2]; /* .filter -> lchat */
	+ int fds_write[2]; /* lchat -> .filter */
	+
	+ if (pipe(fds_read) == -1)
	+ err(EXIT_FAILURE, "pipe");
	+ if (pipe(fds_write) == -1)
	+ err(EXIT_FAILURE, "pipe");
	+
	+ switch (fork()) {
	+ case -1:
	+ err(EXIT_FAILURE, "fork of .filter");
	+ case 0: /* child */
	+ if (dup2(fds_read[1], STDOUT_FILENO) == -1)
	+ err(EXIT_FAILURE, "dup2");
	+ if (dup2(fds_write[0], STDIN_FILENO) == -1)
	+ err(EXIT_FAILURE, "dup2");
	+
	+ if (close(fds_read[0]) == -1)
	+ err(EXIT_FAILURE, "close");
	+ if (close(fds_write[1]) == -1)
	+ err(EXIT_FAILURE, "close");
	+
	+ execl("./.filter", "./.filter", NULL);
	+ err(EXIT_FAILURE, "exec of .filter");
	+ }
	+
	+ /* parent */
	+ if (close(fds_read[1]) == -1)
	+ err(EXIT_FAILURE, "close");
	+ if (close(fds_write[0]) == -1)
	+ err(EXIT_FAILURE, "close");
	+
	+ *read = fds_read[0];
	+ *write = fds_write[1];
	+}
	+
	+static void
	usage(void)
	{
	fprintf(stderr, "lchat [-aeh] [-n lines] [-p prompt] [-t title] [-i in…
	@@ -129,11 +168,13 @@ usage(void)
	int
	main(int argc, char *argv[])
	{
	- struct pollfd pfd[2];
	+ struct pollfd pfd[3];
	struct termios term;
	struct slackline *sl = sl_init();
	int fd = STDIN_FILENO;
	int read_fd = 6;
	+ int read_filter = -1;
	+ int backend_sink = STDOUT_FILENO;
	char c;
	int ch;
	bool empty_line = false;
	@@ -260,27 +301,35 @@ main(int argc, char *argv[])
	snprintf(tail_cmd, sizeof tail_cmd, "exec tail -n %zd -f %s",
	history_len, out_file);

	- if (access(".filter", X_OK) == 0)
	- strlcat(tail_cmd, " \| ./.filter", sizeof tail_cmd);
	-
	if ((fh = popen(tail_cmd, "r")) == NULL)
	err(EXIT_FAILURE, "unable to open pipe to tail");

	read_fd = fileno(fh);
	}

	+ int nfds = 2;
	+
	pfd[0].fd = fd;
	pfd[0].events = POLLIN;

	pfd[1].fd = read_fd;
	pfd[1].events = POLLIN;

	+ if (access(".filter", X_OK) == 0) {
	+ fork_filter(&read_filter, &backend_sink);
	+
	+ pfd[2].fd = read_filter;
	+ pfd[2].events = POLLIN;
	+
	+ nfds = 3;
	+ }
	+
	/* print initial prompt */
	fputs(prompt, stdout);

	for (;;) {
	errno = 0;
	- if (poll(pfd, 2, INFTIM) == -1 && errno != EINTR)
	+ if (poll(pfd, nfds, INFTIM) == -1 && errno != EINTR)
	err(EXIT_FAILURE, "poll");

	/* moves cursor back after linewrap */
	@@ -338,7 +387,7 @@ main(int argc, char *argv[])
	errx(EXIT_FAILURE, "backend exited");
	if (n == -1)
	err(EXIT_FAILURE, "read");
	- if (write(STDOUT_FILENO, buf, n) == -1)
	+ if (write(backend_sink, buf, n) == -1)
	err(EXIT_FAILURE, "write");

	/* terminate the input buffer with NUL */
	@@ -348,6 +397,28 @@ main(int argc, char *argv[])
	if (bell_flag && bell_match(buf, bell_file))
	putchar('\a');
	}
	+
	+ /* handel optional .filter i/o */
	+ if (nfds > 2) {
	+ /* handle .filter error and its broken pipe */
	+ if (pfd[2].revents & POLLHUP)
	+ break;
	+ if (pfd[2].revents & POLLERR \|\|
	+ pfd[2].revents & POLLNVAL)
	+ errx(EXIT_FAILURE, ".filter error");
	+
	+ /* handle .filter output */
	+ if (pfd[2].revents & POLLIN) {
	+ char buf[BUFSIZ];
	+ ssize_t n = read(pfd[2].fd, buf, sizeof buf);
	+ if (n == 0)
	+ errx(EXIT_FAILURE, ".filter exited");
	+ if (n == -1)
	+ err(EXIT_FAILURE, "read");
	+ if (write(STDOUT_FILENO, buf, n) == -1)
	+ err(EXIT_FAILURE, "write");
	+ }
	+ }
	out:
	/* show current input line */
	fputs(prompt, stdout);