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File: [cvsweb.bsd.lv] / mandoc / term_tag.c (download)

Revision 1.6, Tue Mar 30 17:16:55 2021 UTC (2 years, 11 months ago) by schwarze
Branch: MAIN
CVS Tags: VERSION_1_14_6, HEAD
Changes since 1.5: +6 -5 lines

Append .html suffix to temporary files enabling browsers to recognise it.

Occasionally one might read a manual page in a webbrowser, e.g.
"MANPAGER=firefox man -T html jq", however temporary files created for
pagers lack file extensions and most web browsers are unable to detect a
file's content without it.

Special case mandoc(1)'s HTML output format by appending the ".html" suffix
to file names such that browsers will actually render HTML as such instead
of showing it as plain text.

Idea and patch from kn@, with minor help from me.

/* $Id: term_tag.c,v 1.6 2021/03/30 17:16:55 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 <fcntl.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 "roff_int.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(const char *outfilename, const char *suffix,
    const char *tagfilename)
{
	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. */

	if (outfilename == NULL) {
		(void)snprintf(tag_files.ofn, sizeof(tag_files.ofn),
		    "/tmp/man.XXXXXXXXXX%s", suffix);
		if ((ofd = mkstemps(tag_files.ofn, strlen(suffix))) == -1) {
			mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
			    "%s: %s", tag_files.ofn, strerror(errno));
			goto fail;
		}
	} else {
		(void)strlcpy(tag_files.ofn, outfilename,
		   sizeof(tag_files.ofn));
		unlink(outfilename);
		ofd = open(outfilename, O_WRONLY | O_CREAT | O_EXCL, 0644);
		if (ofd == -1) {
			mandoc_msg(MANDOCERR_OPEN, 0, 0,
			    "%s: %s", outfilename, strerror(errno));
			goto fail;
		}
	}
	if (tagfilename == NULL) {
		(void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
		    sizeof(tag_files.tfn));
		if ((tfd = mkstemp(tag_files.tfn)) == -1) {
			mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
			    "%s: %s", tag_files.tfn, strerror(errno));
			goto fail;
		}
	} else {
		(void)strlcpy(tag_files.tfn, tagfilename,
		    sizeof(tag_files.tfn));
		unlink(tagfilename);
		tfd = open(tagfilename, O_WRONLY | O_CREAT | O_EXCL, 0644);
		if (tfd == -1) {
			mandoc_msg(MANDOCERR_OPEN, 0, 0,
			    "%s: %s", tagfilename, 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;
	cp = n->tag == NULL ? n->child->string : n->tag;
	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 (strncmp(tag_files.ofn, "/tmp/man.", 9) == 0) {
		unlink(tag_files.ofn);
		*tag_files.ofn = '\0';
	}
	if (strncmp(tag_files.tfn, "/tmp/man.", 9) == 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);
}