Return to term_tag.c CVS log

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When the last file formatted yielded no tags, the tags file got
deleted before starting the pager, even when earlier input files
had written to it; thanks to weerd@ for reporting that bug.

Since we now generate tags for section headers, we almost always
generate at least some.  Consequently, while fixing the above bug,
simplify the code by never deleting the tags file before the pager
exits, not even in the rare case that the file happens to be empty.
Hence, this patch is -75 +63 LOC even though it fixes two bugs.

While deleting the output files belongs after exit from the pager,
closing them should be done before it is started.  Collect the
related code, which was scattered in various places, to where
it belongs, in a dedicated function in the term_tag.c module.
As a side benefit, never fclose(2) stdout, only dup2(2) to it.

Similarly, when the -O tag argument wasn't found in the last file
formatted, there was a complaint about "no such tag" even when the
argument did occur in earlier files.  Fix that by looking for a
matching tag after every formatted file rather than just once at
the very end.  Given that command line arguments aren't properties
of the file(s) being formatted, that check is a job for the main
program, not for the formatters, so while fixing the check, move
it from term_tag.c to main.c.

/* $Id: term_tag.c,v 1.2 2020/04/02 22:12:55 schwarze Exp $ */
/*
 * Copyright (c) 2015,2016,2018,2019,2020 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Functions to write a ctags(1) file.
 * For use by the mandoc(1) ASCII and UTF-8 formatters only.
 */
#include "config.h"

#include <sys/types.h>

#include <errno.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "mandoc.h"
#include "roff.h"
#include "tag.h"
#include "term_tag.h"

static void tag_signal(int) __attribute__((__noreturn__));

static struct tag_files tag_files;


/*
 * Prepare for using a pager.
 * Not all pagers are capable of using a tag file,
 * but for simplicity, create it anyway.
 */
struct tag_files *
term_tag_init(void)
{
	struct sigaction	 sa;
	int			 ofd;	/* In /tmp/, dup(2)ed to stdout. */
	int			 tfd;

	ofd = tfd = -1;
	tag_files.tfs = NULL;
	tag_files.tcpgid = -1;

	/* Clean up when dying from a signal. */

	memset(&sa, 0, sizeof(sa));
	sigfillset(&sa.sa_mask);
	sa.sa_handler = tag_signal;
	sigaction(SIGHUP, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGTERM, &sa, NULL);

	/*
	 * POSIX requires that a process calling tcsetpgrp(3)
	 * from the background gets a SIGTTOU signal.
	 * In that case, do not stop.
	 */

	sa.sa_handler = SIG_IGN;
	sigaction(SIGTTOU, &sa, NULL);

	/* Save the original standard output for use by the pager. */

	if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1) {
		mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
		goto fail;
	}

	/* Create both temporary output files. */

	(void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
	    sizeof(tag_files.ofn));
	(void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
	    sizeof(tag_files.tfn));
	if ((ofd = mkstemp(tag_files.ofn)) == -1) {
		mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
		    "%s: %s", tag_files.ofn, strerror(errno));
		goto fail;
	}
	if ((tfd = mkstemp(tag_files.tfn)) == -1) {
		mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
		    "%s: %s", tag_files.tfn, strerror(errno));
		goto fail;
	}
	if ((tag_files.tfs = fdopen(tfd, "w")) == NULL) {
		mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
		goto fail;
	}
	tfd = -1;
	if (dup2(ofd, STDOUT_FILENO) == -1) {
		mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
		goto fail;
	}
	close(ofd);
	return &tag_files;

fail:
	term_tag_unlink();
	if (ofd != -1)
		close(ofd);
	if (tfd != -1)
		close(tfd);
	if (tag_files.ofd != -1) {
		close(tag_files.ofd);
		tag_files.ofd = -1;
	}
	return NULL;
}

void
term_tag_write(struct roff_node *n, size_t line)
{
	const char	*cp;
	int		 len;

	if (tag_files.tfs == NULL)
		return;
	if (n->string == NULL)
		n = n->child;
	cp = n->string;
	if (cp[0] == '\\' && (cp[1] == '&' || cp[1] == 'e'))
		cp += 2;
	len = strcspn(cp, " \t\\");
	fprintf(tag_files.tfs, "%.*s %s %zu\n",
	    len, cp, tag_files.ofn, line);
}

/*
 * Close both output files and restore the original standard output
 * to the terminal.  In the unlikely case that the latter fails,
 * trying to start a pager would be useless, so report the failure
 * to the main program.
 */
int
term_tag_close(void)
{
	int irc = 0;

	if (tag_files.tfs != NULL) {
		fclose(tag_files.tfs);
		tag_files.tfs = NULL;
	}
	if (tag_files.ofd != -1) {
		fflush(stdout);
		if ((irc = dup2(tag_files.ofd, STDOUT_FILENO)) == -1)
			mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
		close(tag_files.ofd);
		tag_files.ofd = -1;
	}
	return irc;
}

void
term_tag_unlink(void)
{
	pid_t	 tc_pgid;

	if (tag_files.tcpgid != -1) {
		tc_pgid = tcgetpgrp(STDOUT_FILENO);
		if (tc_pgid == tag_files.pager_pid ||
		    tc_pgid == getpgid(0) ||
		    getpgid(tc_pgid) == -1)
			(void)tcsetpgrp(STDOUT_FILENO, tag_files.tcpgid);
	}
	if (*tag_files.ofn != '\0') {
		unlink(tag_files.ofn);
		*tag_files.ofn = '\0';
	}
	if (*tag_files.tfn != '\0') {
		unlink(tag_files.tfn);
		*tag_files.tfn = '\0';
	}
}

static void
tag_signal(int signum)
{
	struct sigaction	 sa;

	term_tag_unlink();
	memset(&sa, 0, sizeof(sa));
	sigemptyset(&sa.sa_mask);
	sa.sa_handler = SIG_DFL;
	sigaction(signum, &sa, NULL);
	kill(getpid(), signum);
	/* NOTREACHED */
	_exit(1);
}