Some time ago, i simplified mandoc_msg() such that it can be used

everywhere and not only in the parsers.
For more uniform messages, use it at more places instead of err(3),
in particular in the main program.
While here, integrate a few trivial functions called at exactly one
place into the main option parser, and let a few more functions use
the normal convention of returning 0 for success and -1 for error.

7 files changed, 344 insertions, 242 deletions

diff --git a/usr.bin/mandoc/main.c b/usr.bin/mandoc/main.c
index 51549ee3057..66d6a1173b0 100644
--- a/usr.bin/mandoc/main.c
+++ b/usr.bin/mandoc/main.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: main.c,v 1.230 2019/07/03 16:33:06 espie Exp $ */
+/*	$OpenBSD: main.c,v 1.231 2019/07/10 19:38:56 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2012, 2014-2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -92,13 +92,10 @@ static	int		  fs_lookup(const struct manpaths *,
 static	int		  fs_search(const struct mansearch *,
 				const struct manpaths *, int, char**,
 				struct manpage **, size_t *);
-static	int		  koptions(int *, char *);
-static	void		  moptions(int *, char *);
 static	void		  outdata_alloc(struct curparse *);
 static	void		  parse(struct curparse *, int, const char *);
-static	void		  passthrough(const char *, int, int);
+static	void		  passthrough(int, int);
 static	pid_t		  spawn_pager(struct tag_files *);
-static	int		  toptions(struct curparse *, char *);
 static	void		  usage(enum argmode) __attribute__((__noreturn__));
 static	int		  woptions(struct curparse *, char *);
 
@@ -137,8 +134,10 @@ main(int argc, char *argv[])
 	    strncmp(progname, "makewhatis", 10) == 0)
 		return mandocdb(argc, argv);
 
-	if (pledge("stdio rpath tmppath tty proc exec", NULL) == -1)
-		err((int)MANDOCLEVEL_SYSERR, "pledge");
+	if (pledge("stdio rpath tmppath tty proc exec", NULL) == -1) {
+		mandoc_msg(MANDOCERR_PLEDGE, 0, 0, "%s", strerror(errno));
+		return mandoc_msg_getrc();
+	}
 
 	/* Search options. */
 
@@ -198,19 +197,29 @@ main(int argc, char *argv[])
 			outmode = OUTMODE_ALL;
 			break;
 		case 'I':
-			if (strncmp(optarg, "os=", 3)) {
-				warnx("-I %s: Bad argument", optarg);
-				return (int)MANDOCLEVEL_BADARG;
+			if (strncmp(optarg, "os=", 3) != 0) {
+				mandoc_msg(MANDOCERR_BADARG_BAD, 0, 0,
+				    "-I %s", optarg);
+				return mandoc_msg_getrc();
 			}
 			if (curp.os_s != NULL) {
-				warnx("-I %s: Duplicate argument", optarg);
-				return (int)MANDOCLEVEL_BADARG;
+				mandoc_msg(MANDOCERR_BADARG_DUPE, 0, 0,
+				    "-I %s", optarg);
+				return mandoc_msg_getrc();
 			}
 			curp.os_s = mandoc_strdup(optarg + 3);
 			break;
 		case 'K':
-			if ( ! koptions(&options, optarg))
-				return (int)MANDOCLEVEL_BADARG;
+			options &= ~(MPARSE_UTF8 | MPARSE_LATIN1);
+			if (strcmp(optarg, "utf-8") == 0)
+				options |=  MPARSE_UTF8;
+			else if (strcmp(optarg, "iso-8859-1") == 0)
+				options |=  MPARSE_LATIN1;
+			else if (strcmp(optarg, "us-ascii") != 0) {
+				mandoc_msg(MANDOCERR_BADARG_BAD, 0, 0,
+				    "-K %s", optarg);
+				return mandoc_msg_getrc();
+			}
 			break;
 		case 'k':
 			search.argmode = ARG_EXPR;
@@ -235,12 +244,37 @@ main(int argc, char *argv[])
 			search.sec = optarg;
 			break;
 		case 'T':
-			if ( ! toptions(&curp, optarg))
-				return (int)MANDOCLEVEL_BADARG;
+			if (strcmp(optarg, "ascii") == 0)
+				curp.outtype = OUTT_ASCII;
+			else if (strcmp(optarg, "lint") == 0) {
+				curp.outtype = OUTT_LINT;
+				mandoc_msg_setoutfile(stdout);
+				mandoc_msg_setmin(MANDOCERR_BASE);
+			} else if (strcmp(optarg, "tree") == 0)
+				curp.outtype = OUTT_TREE;
+			else if (strcmp(optarg, "man") == 0)
+				curp.outtype = OUTT_MAN;
+			else if (strcmp(optarg, "html") == 0)
+				curp.outtype = OUTT_HTML;
+			else if (strcmp(optarg, "markdown") == 0)
+				curp.outtype = OUTT_MARKDOWN;
+			else if (strcmp(optarg, "utf8") == 0)
+				curp.outtype = OUTT_UTF8;
+			else if (strcmp(optarg, "locale") == 0)
+				curp.outtype = OUTT_LOCALE;
+			else if (strcmp(optarg, "ps") == 0)
+				curp.outtype = OUTT_PS;
+			else if (strcmp(optarg, "pdf") == 0)
+				curp.outtype = OUTT_PDF;
+			else {
+				mandoc_msg(MANDOCERR_BADARG_BAD, 0, 0,
+				    "-T %s", optarg);
+				return mandoc_msg_getrc();
+			}
 			break;
 		case 'W':
-			if ( ! woptions(&curp, optarg))
-				return (int)MANDOCLEVEL_BADARG;
+			if (woptions(&curp, optarg) == -1)
+				return mandoc_msg_getrc();
 			break;
 		case 'w':
 			outmode = OUTMODE_FLN;
@@ -278,7 +312,7 @@ main(int argc, char *argv[])
 			while (oarg != NULL) {
 				if (manconf_output(&conf.output,
 				    strsep(&oarg, ","), 0) == -1)
-					return (int)MANDOCLEVEL_BADARG;
+					return mandoc_msg_getrc();
 			}
 		}
 	}
@@ -301,9 +335,13 @@ main(int argc, char *argv[])
 			conf.output.indent = 3;
 	}
 
-	if (!use_pager)
-		if (pledge("stdio rpath", NULL) == -1)
-			err((int)MANDOCLEVEL_SYSERR, "pledge");
+	if (use_pager == 0) {
+		if (pledge("stdio rpath", NULL) == -1) {
+			mandoc_msg(MANDOCERR_PLEDGE, 0, 0,
+			    "%s", strerror(errno));
+			return mandoc_msg_getrc();
+		}
+	}
 
 	/* Parse arguments. */
 
@@ -365,7 +403,7 @@ main(int argc, char *argv[])
 			usage(search.argmode);
 
 		if (sz == 0 && search.argmode == ARG_NAME)
-			fs_search(&search, &conf.manpath,
+			(void)fs_search(&search, &conf.manpath,
 			    argc, argv, &res, &sz);
 
 		if (search.argmode == ARG_NAME) {
@@ -373,7 +411,10 @@ main(int argc, char *argv[])
 				if (strchr(argv[c], '/') == NULL)
 					continue;
 				if (access(argv[c], R_OK) == -1) {
-					warn("%s", argv[c]);
+					mandoc_msg_setinfilename(argv[c]);
+					mandoc_msg(MANDOCERR_BADARG_BAD,
+					    0, 0, "%s", strerror(errno));
+					mandoc_msg_setinfilename(NULL);
 					continue;
 				}
 				res = mandoc_reallocarray(res,
@@ -458,15 +499,25 @@ main(int argc, char *argv[])
 	/* mandoc(1) */
 
 	if (use_pager) {
-		if (pledge("stdio rpath tmppath tty proc exec", NULL) == -1)
-			err((int)MANDOCLEVEL_SYSERR, "pledge");
+		if (pledge("stdio rpath tmppath tty proc exec", NULL) == -1) {
+			mandoc_msg(MANDOCERR_PLEDGE, 0, 0,
+			    "%s", strerror(errno));
+			return mandoc_msg_getrc();
+		}
 	} else {
-		if (pledge("stdio rpath", NULL) == -1)
-			err((int)MANDOCLEVEL_SYSERR, "pledge");
+		if (pledge("stdio rpath", NULL) == -1) {
+			mandoc_msg(MANDOCERR_PLEDGE, 0, 0,
+			    "%s", strerror(errno));
+			return mandoc_msg_getrc();
+		}
 	}
 
-	if (search.argmode == ARG_FILE)
-		moptions(&options, auxpaths);
+	if (search.argmode == ARG_FILE && auxpaths != NULL) {
+		if (strcmp(auxpaths, "doc") == 0)
+			options |= MPARSE_MDOC;
+		else if (strcmp(auxpaths, "an") == 0)
+			options |= MPARSE_MAN;
+	}
 
 	mchars_alloc();
 	curp.mp = mparse_alloc(options, curp.os_e, curp.os_s);
@@ -508,6 +559,7 @@ main(int argc, char *argv[])
 		} else
 			thisarg = *argv;
 
+		mandoc_msg_setinfilename(thisarg);
 		fd = mparse_open(curp.mp, thisarg);
 		if (fd != -1) {
 			if (use_pager) {
@@ -517,22 +569,21 @@ main(int argc, char *argv[])
 					tag_files->tagname = conf.output.tag;
 			}
 
-			mandoc_msg_setinfilename(thisarg);
 			if (resp == NULL || resp->form == FORM_SRC)
 				parse(&curp, fd, thisarg);
 			else
-				passthrough(resp->file, fd,
-				    conf.output.synopsisonly);
-			mandoc_msg_setinfilename(NULL);
+				passthrough(fd, conf.output.synopsisonly);
 
 			if (ferror(stdout)) {
 				if (tag_files != NULL) {
-					warn("%s", tag_files->ofn);
+					mandoc_msg(MANDOCERR_WRITE, 0, 0,
+					    "%s: %s", tag_files->ofn,
+					    strerror(errno));
 					tag_unlink();
 					tag_files = NULL;
 				} else
-					warn("stdout");
-				mandoc_msg_setrc(MANDOCLEVEL_SYSERR);
+					mandoc_msg(MANDOCERR_WRITE, 0, 0,
+					    "%s", strerror(errno));
 				break;
 			}
 
@@ -542,8 +593,10 @@ main(int argc, char *argv[])
 				terminal_sepline(curp.outdata);
 			}
 		} else
-			mandoc_msg(MANDOCERR_FILE, 0, 0,
-			    "%s: %s", thisarg, strerror(errno));
+			mandoc_msg(resp == NULL ? MANDOCERR_BADARG_BAD :
+			    MANDOCERR_OPEN, 0, 0, "%s", strerror(errno));
+
+		mandoc_msg_setinfilename(NULL);
 
 		if (curp.wstop && mandoc_msg_getrc() != MANDOCLEVEL_OK)
 			break;
@@ -635,8 +688,8 @@ out:
 				continue;
 
 			if (pid == -1) {
-				warn("wait");
-				mandoc_msg_setrc(MANDOCLEVEL_SYSERR);
+				mandoc_msg(MANDOCERR_WAIT, 0, 0,
+				    "%s", strerror(errno));
 				break;
 			}
 			if (!WIFSTOPPED(status))
@@ -652,7 +705,6 @@ out:
 static void
 usage(enum argmode argmode)
 {
-
 	switch (argmode) {
 	case ARG_FILE:
 		fputs("usage: mandoc [-ac] [-I os=name] "
@@ -717,7 +769,8 @@ fs_lookup(const struct manpaths *paths, size_t ipath,
 	    paths->paths[ipath], sec, name);
 	globres = glob(file, 0, NULL, &globinfo);
 	if (globres != 0 && globres != GLOB_NOMATCH)
-		warn("%s: glob", file);
+		mandoc_msg(MANDOCERR_GLOB, 0, 0,
+		    "%s: %s", file, strerror(errno));
 	free(file);
 	if (globres == 0)
 		file = mandoc_strdup(*globinfo.gl_pathv);
@@ -728,21 +781,21 @@ fs_lookup(const struct manpaths *paths, size_t ipath,
 		free(file);
 	}
 	if (res != NULL || ipath + 1 != paths->sz)
-		return 0;
+		return -1;
 
 	mandoc_asprintf(&file, "%s.%s", name, sec);
 	globres = stat(file, &sb);
 	free(file);
-	return globres != -1;
+	return globres;
 
 found:
 	warnx("outdated mandoc.db lacks %s(%s) entry, run makewhatis %s",
 	    name, sec, paths->paths[ipath]);
 	if (res == NULL) {
 		free(file);
-		return 1;
+		return 0;
 	}
-	*res = mandoc_reallocarray(*res, ++*ressz, sizeof(struct manpage));
+	*res = mandoc_reallocarray(*res, ++*ressz, sizeof(**res));
 	page = *res + (*ressz - 1);
 	page->file = file;
 	page->names = NULL;
@@ -751,7 +804,7 @@ found:
 	page->ipath = ipath;
 	page->sec = (*sec >= '1' && *sec <= '9') ? *sec - '1' + 1 : 10;
 	page->form = form;
-	return 1;
+	return 0;
 }
 
 static int
@@ -773,14 +826,14 @@ fs_search(const struct mansearch *cfg, const struct manpaths *paths,
 		for (ipath = 0; ipath < paths->sz; ipath++) {
 			if (cfg->sec != NULL) {
 				if (fs_lookup(paths, ipath, cfg->sec,
-				    cfg->arch, *argv, res, ressz) &&
+				    cfg->arch, *argv, res, ressz) != -1 &&
 				    cfg->firstmatch)
-					return 1;
+					return 0;
 			} else for (isec = 0; isec < nsec; isec++)
 				if (fs_lookup(paths, ipath, sections[isec],
-				    cfg->arch, *argv, res, ressz) &&
+				    cfg->arch, *argv, res, ressz) != -1 &&
 				    cfg->firstmatch)
-					return 1;
+					return 0;
 		}
 		if (res != NULL && *ressz == lastsz &&
 		    strchr(*argv, '/') == NULL) {
@@ -799,7 +852,7 @@ fs_search(const struct mansearch *cfg, const struct manpaths *paths,
 		argv++;
 		argc--;
 	}
-	return 0;
+	return -1;
 }
 
 static void
@@ -906,7 +959,7 @@ check_xr(void)
 		search.firstmatch = 1;
 		if (mansearch(&search, &paths, 1, &xr->name, NULL, &sz))
 			continue;
-		if (fs_search(&search, &paths, 1, &xr->name, NULL, &sz))
+		if (fs_search(&search, &paths, 1, &xr->name, NULL, &sz) != -1)
 			continue;
 		if (xr->count == 1)
 			mandoc_msg(MANDOCERR_XR_BAD, xr->line,
@@ -946,34 +999,34 @@ outdata_alloc(struct curparse *curp)
 }
 
 static void
-passthrough(const char *file, int fd, int synopsis_only)
+passthrough(int fd, int synopsis_only)
 {
 	const char	 synb[] = "S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS";
 	const char	 synr[] = "SYNOPSIS";
 
 	FILE		*stream;
-	const char	*syscall;
 	char		*line, *cp;
 	size_t		 linesz;
 	ssize_t		 len, written;
-	int		 print;
+	int		 lno, print;
 
+	stream = NULL;
 	line = NULL;
 	linesz = 0;
 
 	if (fflush(stdout) == EOF) {
-		syscall = "fflush";
-		goto fail;
+		mandoc_msg(MANDOCERR_FFLUSH, 0, 0, "%s", strerror(errno));
+		goto done;
 	}
-
 	if ((stream = fdopen(fd, "r")) == NULL) {
 		close(fd);
-		syscall = "fdopen";
-		goto fail;
+		mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
+		goto done;
 	}
 
-	print = 0;
+	lno = print = 0;
 	while ((len = getline(&line, &linesz, stream)) != -1) {
+		lno++;
 		cp = line;
 		if (synopsis_only) {
 			if (print) {
@@ -991,94 +1044,20 @@ passthrough(const char *file, int fd, int synopsis_only)
 			}
 		}
 		for (; len > 0; len -= written) {
-			if ((written = write(STDOUT_FILENO, cp, len)) != -1)
-				continue;
-			fclose(stream);
-			syscall = "write";
-			goto fail;
+			if ((written = write(STDOUT_FILENO, cp, len)) == -1) {
+				mandoc_msg(MANDOCERR_WRITE, 0, 0,
+				    "%s", strerror(errno));
+				goto done;
+			}
 		}
 	}
-
-	if (ferror(stream)) {
-		fclose(stream);
-		syscall = "getline";
-		goto fail;
-	}
+	if (ferror(stream))
+		mandoc_msg(MANDOCERR_GETLINE, lno, 0, "%s", strerror(errno));
 
 done:
 	free(line);
-	fclose(stream);
-	return;
-
-fail:
-	free(line);
-	warn("%s: SYSERR: %s", file, syscall);
-	mandoc_msg_setrc(MANDOCLEVEL_SYSERR);
-}
-
-static int
-koptions(int *options, char *arg)
-{
-
-	if ( ! strcmp(arg, "utf-8")) {
-		*options |=  MPARSE_UTF8;
-		*options &= ~MPARSE_LATIN1;
-	} else if ( ! strcmp(arg, "iso-8859-1")) {
-		*options |=  MPARSE_LATIN1;
-		*options &= ~MPARSE_UTF8;
-	} else if ( ! strcmp(arg, "us-ascii")) {
-		*options &= ~(MPARSE_UTF8 | MPARSE_LATIN1);
-	} else {
-		warnx("-K %s: Bad argument", arg);
-		return 0;
-	}
-	return 1;
-}
-
-static void
-moptions(int *options, char *arg)
-{
-
-	if (arg == NULL)
-		return;
-	if (strcmp(arg, "doc") == 0)
-		*options |= MPARSE_MDOC;
-	else if (strcmp(arg, "an") == 0)
-		*options |= MPARSE_MAN;
-}
-
-static int
-toptions(struct curparse *curp, char *arg)
-{
-
-	if (0 == strcmp(arg, "ascii"))
-		curp->outtype = OUTT_ASCII;
-	else if (0 == strcmp(arg, "lint")) {
-		curp->outtype = OUTT_LINT;
-		mandoc_msg_setoutfile(stdout);
-		mandoc_msg_setmin(MANDOCERR_BASE);
-	} else if (0 == strcmp(arg, "tree"))
-		curp->outtype = OUTT_TREE;
-	else if (0 == strcmp(arg, "man"))
-		curp->outtype = OUTT_MAN;
-	else if (0 == strcmp(arg, "html"))
-		curp->outtype = OUTT_HTML;
-	else if (0 == strcmp(arg, "markdown"))
-		curp->outtype = OUTT_MARKDOWN;
-	else if (0 == strcmp(arg, "utf8"))
-		curp->outtype = OUTT_UTF8;
-	else if (0 == strcmp(arg, "locale"))
-		curp->outtype = OUTT_LOCALE;
-	else if (0 == strcmp(arg, "ps"))
-		curp->outtype = OUTT_PS;
-	else if (0 == strcmp(arg, "pdf"))
-		curp->outtype = OUTT_PDF;
-	else {
-		warnx("-T %s: Bad argument", arg);
-		return 0;
-	}
-
-	return 1;
+	if (stream != NULL)
+		fclose(stream);
 }
 
 static int
@@ -1122,7 +1101,7 @@ woptions(struct curparse *curp, char *arg)
 			mandoc_msg_setmin(MANDOCERR_UNSUPP);
 			break;
 		case 7:
-			mandoc_msg_setmin(MANDOCERR_MAX);
+			mandoc_msg_setmin(MANDOCERR_BADARG);
 			break;
 		case 8:
 			mandoc_msg_setmin(MANDOCERR_BASE);
@@ -1133,11 +1112,11 @@ woptions(struct curparse *curp, char *arg)
 			curp->os_e = MANDOC_OS_NETBSD;
 			break;
 		default:
-			warnx("-W %s: Bad argument", o);
-			return 0;
+			mandoc_msg(MANDOCERR_BADARG_BAD, 0, 0, "-W %s", o);
+			return -1;
 		}
 	}
-	return 1;
+	return 0;
 }
 
 static pid_t
@@ -1198,22 +1177,28 @@ spawn_pager(struct tag_files *tag_files)
 
 	switch (pager_pid = fork()) {
 	case -1:
-		err((int)MANDOCLEVEL_SYSERR, "fork");
+		mandoc_msg(MANDOCERR_FORK, 0, 0, "%s", strerror(errno));
+		exit(mandoc_msg_getrc());
 	case 0:
 		break;
 	default:
 		(void)setpgid(pager_pid, 0);
 		(void)tcsetpgrp(tag_files->ofd, pager_pid);
-		if (pledge("stdio rpath tmppath tty proc", NULL) == -1)
-			err((int)MANDOCLEVEL_SYSERR, "pledge");
+		if (pledge("stdio rpath tmppath tty proc", NULL) == -1) {
+			mandoc_msg(MANDOCERR_PLEDGE, 0, 0,
+			    "%s", strerror(errno));
+			exit(mandoc_msg_getrc());
+		}
 		tag_files->pager_pid = pager_pid;
 		return pager_pid;
 	}
 
 	/* The child process becomes the pager. */
 
-	if (dup2(tag_files->ofd, STDOUT_FILENO) == -1)
-		err((int)MANDOCLEVEL_SYSERR, "pager stdout");
+	if (dup2(tag_files->ofd, STDOUT_FILENO) == -1) {
+		mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
+		_exit(mandoc_msg_getrc());
+	}
 	close(tag_files->ofd);
 	assert(tag_files->tfd == -1);
 
@@ -1223,5 +1208,6 @@ spawn_pager(struct tag_files *tag_files)
 		nanosleep(&timeout, NULL);
 
 	execvp(argv[0], argv);
-	err((int)MANDOCLEVEL_SYSERR, "exec %s", argv[0]);
+	mandoc_msg(MANDOCERR_EXEC, 0, 0, "%s: %s", argv[0], strerror(errno));
+	_exit(mandoc_msg_getrc());
 }
diff --git a/usr.bin/mandoc/mandoc.1 b/usr.bin/mandoc/mandoc.1
index ef4169477a9..79ef8b019b2 100644
--- a/usr.bin/mandoc/mandoc.1
+++ b/usr.bin/mandoc/mandoc.1
@@ -1,7 +1,7 @@
-.\"	$OpenBSD: mandoc.1,v 1.163 2019/05/26 01:16:09 naddy Exp $
+.\"	$OpenBSD: mandoc.1,v 1.164 2019/07/10 19:38:56 schwarze Exp $
 .\"
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
-.\" Copyright (c) 2012, 2014-2018 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2012, 2014-2019 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
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: May 26 2019 $
+.Dd $Mdocdate: July 10 2019 $
 .Dt MANDOC 1
 .Os
 .Sh NAME
@@ -698,7 +698,7 @@ No input files have been read.
 .It 6
 An operating system error occurred, for example exhaustion
 of memory, file descriptors, or process table entries.
-Such errors cause
+Such errors may cause
 .Nm
 to exit at once, possibly in the middle of parsing or formatting a file.
 .El
@@ -778,6 +778,13 @@ fields.
 .Pp
 Message levels have the following meanings:
 .Bl -tag -width "warning"
+.It Cm syserr
+An operating system error occurred.
+There isn't necessarily anything wrong with the input files.
+Output may all the same be missing or incomplete.
+.It Cm badarg
+Invalid command line arguments were specified.
+No input files have been read and no output is produced.
 .It Cm unsupp
 An input file uses unsupported low-level
 .Xr roff 7
@@ -826,8 +833,7 @@ Messages of the
 .Cm error ,
 and
 .Cm unsupp
-levels except those about non-existent or unreadable input files
-are hidden unless their level, or a lower level, is requested using a
+levels are hidden unless their level, or a lower level, is requested using a
 .Fl W
 option or
 .Fl T Cm lint
@@ -2242,6 +2248,43 @@ macro or of an undefined macro.
 The macro is ignored, and its arguments are handled
 as if they were a text line.
 .El
+.Ss Bad command line arguments
+.Bl -ohang
+.It Sy "bad command line argument"
+The argument following one of the
+.Fl IKMmOTW
+command line options is invalid, or a
+.Ar file
+given as a command line argument cannot be opened.
+.It Sy "duplicate command line argument"
+The
+.Fl I
+command line option was specified twice.
+.It Sy "option has a superfluous value"
+An argument to the
+.Fl O
+option has a value but does not accept one.
+.It Sy "missing option value"
+An argument to the
+.Fl O
+option has no argument but requires one.
+.It Sy "bad option value"
+An argument to the
+.Fl O
+.Cm indent
+or
+.Cm width
+option has an invalid value.
+.It Sy "duplicate option value"
+The same
+.Fl O
+option is specified more than once.
+.It Sy "no such tag"
+The
+.Fl O Cm tag
+option was specified but the tag was not found in any of the displayed
+manual pages.
+.El
 .Sh SEE ALSO
 .Xr apropos 1 ,
 .Xr man 1 ,
diff --git a/usr.bin/mandoc/mandoc.h b/usr.bin/mandoc/mandoc.h
index 835ee2c95e2..458437ff9be 100644
--- a/usr.bin/mandoc/mandoc.h
+++ b/usr.bin/mandoc/mandoc.h
@@ -1,7 +1,7 @@
-/*	$OpenBSD: mandoc.h,v 1.204 2018/12/15 23:33:20 schwarze Exp $ */
+/*	$OpenBSD: mandoc.h,v 1.205 2019/07/10 19:38:56 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2012-2018 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2012-2019 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
@@ -193,7 +193,6 @@ enum	mandocerr {
 	MANDOCERR_TBLDATA_BLK, /* data block open at end of tbl: macro */
 
 	/* related to document structure and macros */
-	MANDOCERR_FILE, /* cannot open file */
 	MANDOCERR_PROLOG_REP, /* duplicate prologue macro: macro */
 	MANDOCERR_DT_LATE, /* skipping late title macro: Dt args */
 	MANDOCERR_ROFFLOOP, /* input stack limit exceeded, infinite loop? */
@@ -242,6 +241,35 @@ enum	mandocerr {
 	MANDOCERR_TBLLAYOUT_MOD, /* unsupported tbl layout modifier: m */
 	MANDOCERR_TBLMACRO, /* ignoring macro in table: macro */
 
+	MANDOCERR_BADARG, /* ===== start of bad invocations ===== */
+
+	MANDOCERR_BADARG_BAD, /* bad argument */
+	MANDOCERR_BADARG_DUPE, /* duplicate argument */
+	MANDOCERR_BADVAL, /* does not take a value */
+	MANDOCERR_BADVAL_MISS, /* missing argument value */
+	MANDOCERR_BADVAL_BAD, /* bad argument value */
+	MANDOCERR_BADVAL_DUPE, /* duplicate argument value */
+	MANDOCERR_TAG, /* no such tag */
+
+	MANDOCERR_SYSERR, /* ===== start of system errors ===== */
+
+	MANDOCERR_DUP,
+	MANDOCERR_EXEC,
+	MANDOCERR_FDOPEN,
+	MANDOCERR_FFLUSH,
+	MANDOCERR_FORK,
+	MANDOCERR_FSTAT,
+	MANDOCERR_GETLINE,
+	MANDOCERR_GLOB,
+	MANDOCERR_GZCLOSE,
+	MANDOCERR_GZDOPEN,
+	MANDOCERR_MKSTEMP,
+	MANDOCERR_OPEN,
+	MANDOCERR_PLEDGE,
+	MANDOCERR_READ,
+	MANDOCERR_WAIT,
+	MANDOCERR_WRITE,
+
 	MANDOCERR_MAX
 };
 
diff --git a/usr.bin/mandoc/mandoc_msg.c b/usr.bin/mandoc/mandoc_msg.c
index 9d229ac58a6..3f1f777c6bd 100644
--- a/usr.bin/mandoc/mandoc_msg.c
+++ b/usr.bin/mandoc/mandoc_msg.c
@@ -1,7 +1,7 @@
-/*	$OpenBSD: mandoc_msg.c,v 1.4 2019/01/10 06:27:23 schwarze Exp $ */
+/*	$OpenBSD: mandoc_msg.c,v 1.5 2019/07/10 19:38:56 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2014,2015,2016,2017,2018 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2014-2019 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
@@ -27,8 +27,8 @@ static	const enum mandocerr lowest_type[MANDOCLEVEL_MAX] = {
 	MANDOCERR_WARNING,
 	MANDOCERR_ERROR,
 	MANDOCERR_UNSUPP,
-	MANDOCERR_MAX,
-	MANDOCERR_MAX
+	MANDOCERR_BADARG,
+	MANDOCERR_SYSERR
 };
 
 static	const char *const level_name[MANDOCLEVEL_MAX] = {
@@ -191,7 +191,6 @@ static	const char *const type_message[MANDOCERR_MAX] = {
 	"data block open at end of tbl",
 
 	/* related to document structure and macros */
-	NULL,
 	"duplicate prologue macro",
 	"skipping late title macro",
 	"input stack limit exceeded, infinite loop?",
@@ -238,11 +237,40 @@ static	const char *const type_message[MANDOCERR_MAX] = {
 	"eqn delim option in tbl",
 	"unsupported tbl layout modifier",
 	"ignoring macro in table",
+
+	/* bad command line arguments */
+	NULL,
+	"bad command line argument",
+	"duplicate command line argument",
+	"option has a superfluous value",
+	"missing option value",
+	"bad option value",
+	"duplicate option value",
+	"no such tag",
+
+	/* system errors */
+	NULL,
+	"dup",
+	"exec",
+	"fdopen",
+	"fflush",
+	"fork",
+	"fstat",
+	"getline",
+	"glob",
+	"gzclose",
+	"gzdopen",
+	"mkstemp",
+	"open",
+	"pledge",
+	"read",
+	"wait",
+	"write",
 };
 
 static	FILE		*fileptr = NULL;
 static	const char	*filename = NULL;
-static	enum mandocerr	 min_type = MANDOCERR_MAX;
+static	enum mandocerr	 min_type = MANDOCERR_BADARG;
 static	enum mandoclevel rc = MANDOCLEVEL_OK;
 
 
@@ -295,10 +323,10 @@ mandoc_msg(enum mandocerr t, int line, int col, const char *fmt, ...)
 	va_list			 ap;
 	enum mandoclevel	 level;
 
-	if (t < min_type && t != MANDOCERR_FILE)
+	if (t < min_type)
 		return;
 
-	level = MANDOCLEVEL_UNSUPP;
+	level = MANDOCLEVEL_SYSERR;
 	while (t < lowest_type[level])
 		level--;
 	mandoc_msg_setrc(level);
diff --git a/usr.bin/mandoc/manpath.c b/usr.bin/mandoc/manpath.c
index 2e5ffcb15e5..2ac9d86c219 100644
--- a/usr.bin/mandoc/manpath.c
+++ b/usr.bin/mandoc/manpath.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: manpath.c,v 1.26 2019/05/03 18:38:45 schwarze Exp $ */
+/*	$OpenBSD: manpath.c,v 1.27 2019/07/10 19:38:56 schwarze Exp $ */
 /*
- * Copyright (c) 2011,2014,2015,2017,2018 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2011,2014,2015,2017-2019 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  *
  * Permission to use, copy, modify, and distribute this software for any
@@ -19,13 +19,14 @@
 #include <sys/stat.h>
 
 #include <ctype.h>
-#include <err.h>
+#include <errno.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "mandoc_aux.h"
+#include "mandoc.h"
 #include "manconf.h"
 
 #define MAN_CONF_FILE	"/etc/man.conf"
@@ -33,8 +34,8 @@
 #define MANPATH_DEFAULT	"/usr/share/man:/usr/X11R6/man:/usr/local/man"
 
 static	void	 manconf_file(struct manconf *, const char *);
-static	void	 manpath_add(struct manpaths *, const char *, int);
-static	void	 manpath_parseline(struct manpaths *, char *, int);
+static	void	 manpath_add(struct manpaths *, const char *, char);
+static	void	 manpath_parseline(struct manpaths *, char *, char);
 
 
 void
@@ -44,11 +45,11 @@ manconf_parse(struct manconf *conf, const char *file,
 	char		*insert;
 
 	/* Always prepend -m. */
-	manpath_parseline(&conf->manpath, auxp, 1);
+	manpath_parseline(&conf->manpath, auxp, 'm');
 
 	/* If -M is given, it overrides everything else. */
 	if (NULL != defp) {
-		manpath_parseline(&conf->manpath, defp, 1);
+		manpath_parseline(&conf->manpath, defp, 'M');
 		return;
 	}
 
@@ -66,13 +67,13 @@ manconf_parse(struct manconf *conf, const char *file,
 	/* Prepend man.conf(5) to MANPATH. */
 	if (':' == defp[0]) {
 		manconf_file(conf, file);
-		manpath_parseline(&conf->manpath, defp, 0);
+		manpath_parseline(&conf->manpath, defp, '\0');
 		return;
 	}
 
 	/* Append man.conf(5) to MANPATH. */
 	if (':' == defp[strlen(defp) - 1]) {
-		manpath_parseline(&conf->manpath, defp, 0);
+		manpath_parseline(&conf->manpath, defp, '\0');
 		manconf_file(conf, file);
 		return;
 	}
@@ -81,28 +82,28 @@ manconf_parse(struct manconf *conf, const char *file,
 	insert = strstr(defp, "::");
 	if (NULL != insert) {
 		*insert++ = '\0';
-		manpath_parseline(&conf->manpath, defp, 0);
+		manpath_parseline(&conf->manpath, defp, '\0');
 		manconf_file(conf, file);
-		manpath_parseline(&conf->manpath, insert + 1, 0);
+		manpath_parseline(&conf->manpath, insert + 1, '\0');
 		return;
 	}
 
 	/* MANPATH overrides man.conf(5) completely. */
-	manpath_parseline(&conf->manpath, defp, 0);
+	manpath_parseline(&conf->manpath, defp, '\0');
 }
 
 void
 manpath_base(struct manpaths *dirs)
 {
 	char path_base[] = MANPATH_BASE;
-	manpath_parseline(dirs, path_base, 0);
+	manpath_parseline(dirs, path_base, '\0');
 }
 
 /*
  * Parse a FULL pathname from a colon-separated list of arrays.
  */
 static void
-manpath_parseline(struct manpaths *dirs, char *path, int complain)
+manpath_parseline(struct manpaths *dirs, char *path, char option)
 {
 	char	*dir;
 
@@ -110,7 +111,7 @@ manpath_parseline(struct manpaths *dirs, char *path, int complain)
 		return;
 
 	for (dir = strtok(path, ":"); dir; dir = strtok(NULL, ":"))
-		manpath_add(dirs, dir, complain);
+		manpath_add(dirs, dir, option);
 }
 
 /*
@@ -118,33 +119,32 @@ manpath_parseline(struct manpaths *dirs, char *path, int complain)
  * Grow the array one-by-one for simplicity's sake.
  */
 static void
-manpath_add(struct manpaths *dirs, const char *dir, int complain)
+manpath_add(struct manpaths *dirs, const char *dir, char option)
 {
 	char		 buf[PATH_MAX];
 	struct stat	 sb;
 	char		*cp;
 	size_t		 i;
 
-	if (NULL == (cp = realpath(dir, buf))) {
-		if (complain)
-			warn("manpath: %s", dir);
-		return;
-	}
+	if ((cp = realpath(dir, buf)) == NULL)
+		goto fail;
 
 	for (i = 0; i < dirs->sz; i++)
-		if (0 == strcmp(dirs->paths[i], dir))
+		if (strcmp(dirs->paths[i], dir) == 0)
 			return;
 
-	if (stat(cp, &sb) == -1) {
-		if (complain)
-			warn("manpath: %s", dir);
-		return;
-	}
+	if (stat(cp, &sb) == -1)
+		goto fail;
 
 	dirs->paths = mandoc_reallocarray(dirs->paths,
-	    dirs->sz + 1, sizeof(char *));
-
+	    dirs->sz + 1, sizeof(*dirs->paths));
 	dirs->paths[dirs->sz++] = mandoc_strdup(cp);
+	return;
+
+fail:
+	if (option != '\0')
+		mandoc_msg(MANDOCERR_BADARG_BAD, 0, 0,
+		    "-%c %s: %s", option, dir, strerror(errno));
 }
 
 void
@@ -210,7 +210,7 @@ manconf_file(struct manconf *conf, const char *file)
 			*ep = '\0';
 			/* FALLTHROUGH */
 		case 0:  /* manpath */
-			manpath_add(&conf->manpath, cp, 0);
+			manpath_add(&conf->manpath, cp, '\0');
 			*manpath_default = '\0';
 			break;
 		case 1:  /* output */
@@ -225,7 +225,7 @@ manconf_file(struct manconf *conf, const char *file)
 
 out:
 	if (*manpath_default != '\0')
-		manpath_parseline(&conf->manpath, manpath_default, 0);
+		manpath_parseline(&conf->manpath, manpath_default, '\0');
 }
 
 int
@@ -243,7 +243,7 @@ manconf_output(struct manoutput *conf, const char *cp, int fromfile)
 
 	for (tok = 0; tok < ntoks; tok++) {
 		len = strlen(toks[tok]);
-		if ( ! strncmp(cp, toks[tok], len) &&
+		if (strncmp(cp, toks[tok], len) == 0 &&
 		    strchr(" =	", cp[len]) != NULL) {
 			cp += len;
 			if (*cp == '=')
@@ -255,11 +255,11 @@ manconf_output(struct manoutput *conf, const char *cp, int fromfile)
 	}
 
 	if (tok < 6 && *cp == '\0') {
-		warnx("-O %s=?: Missing argument value", toks[tok]);
+		mandoc_msg(MANDOCERR_BADVAL_MISS, 0, 0, "-O %s=?", toks[tok]);
 		return -1;
 	}
 	if (tok > 6 && tok < ntoks && *cp != '\0') {
-		warnx("-O %s: Does not take a value: %s", toks[tok], cp);
+		mandoc_msg(MANDOCERR_BADVAL, 0, 0, "-O %s=%s", toks[tok], cp);
 		return -1;
 	}
 
@@ -300,7 +300,8 @@ manconf_output(struct manoutput *conf, const char *cp, int fromfile)
 		conf->indent = strtonum(cp, 0, 1000, &errstr);
 		if (errstr == NULL)
 			return 0;
-		warnx("-O indent=%s is %s", cp, errstr);
+		mandoc_msg(MANDOCERR_BADVAL_BAD, 0, 0,
+		    "-O indent=%s is %s", cp, errstr);
 		return -1;
 	case 5:
 		if (conf->width) {
@@ -310,7 +311,8 @@ manconf_output(struct manoutput *conf, const char *cp, int fromfile)
 		conf->width = strtonum(cp, 1, 1000, &errstr);
 		if (errstr == NULL)
 			return 0;
-		warnx("-O width=%s is %s", cp, errstr);
+		mandoc_msg(MANDOCERR_BADVAL_BAD, 0, 0,
+		    "-O width=%s is %s", cp, errstr);
 		return -1;
 	case 6:
 		if (conf->tag != NULL) {
@@ -332,12 +334,16 @@ manconf_output(struct manoutput *conf, const char *cp, int fromfile)
 		conf->toc = 1;
 		return 0;
 	default:
-		warnx("-O %s: Bad argument", cp);
+		mandoc_msg(MANDOCERR_BADARG_BAD, 0, 0, "-O %s", cp);
+		return -1;
+	}
+	if (fromfile) {
+		free(oldval);
+		return 0;
+	} else {
+		mandoc_msg(MANDOCERR_BADVAL_DUPE, 0, 0,
+		    "-O %s=%s: already set to %s", toks[tok], cp, oldval);
+		free(oldval);
 		return -1;
 	}
-	if (fromfile == 0)
-		warnx("-O %s=%s: Option already set to %s",
-		    toks[tok], cp, oldval);
-	free(oldval);
-	return -1;
 }
diff --git a/usr.bin/mandoc/read.c b/usr.bin/mandoc/read.c
index 65bf2a56475..6dfe2003abd 100644
--- a/usr.bin/mandoc/read.c
+++ b/usr.bin/mandoc/read.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: read.c,v 1.184 2019/06/03 19:58:00 schwarze Exp $ */
+/*	$OpenBSD: read.c,v 1.185 2019/07/10 19:38:56 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -429,9 +429,8 @@ read_whole_file(struct mparse *curp, int fd, struct buf *fb, int *with_mmap)
 	int		 gzerrnum, retval;
 
 	if (fstat(fd, &st) == -1) {
-		mandoc_msg(MANDOCERR_FILE, 0, 0,
-		    "fstat: %s", strerror(errno));
-		return 0;
+		mandoc_msg(MANDOCERR_FSTAT, 0, 0, "%s", strerror(errno));
+		return -1;
 	}
 
 	/*
@@ -444,13 +443,13 @@ read_whole_file(struct mparse *curp, int fd, struct buf *fb, int *with_mmap)
 	if (curp->gzip == 0 && S_ISREG(st.st_mode)) {
 		if (st.st_size > 0x7fffffff) {
 			mandoc_msg(MANDOCERR_TOOLARGE, 0, 0, NULL);
-			return 0;
+			return -1;
 		}
 		*with_mmap = 1;
 		fb->sz = (size_t)st.st_size;
 		fb->buf = mmap(NULL, fb->sz, PROT_READ, MAP_SHARED, fd, 0);
 		if (fb->buf != MAP_FAILED)
-			return 1;
+			return 0;
 	}
 
 	if (curp->gzip) {
@@ -462,15 +461,15 @@ read_whole_file(struct mparse *curp, int fd, struct buf *fb, int *with_mmap)
 		 * which this function must not do.
 		 */
 		if ((fd = dup(fd)) == -1) {
-			mandoc_msg(MANDOCERR_FILE, 0, 0,
-			    "dup: %s", strerror(errno));
-			return 0;
+			mandoc_msg(MANDOCERR_DUP, 0, 0,
+			    "%s", strerror(errno));
+			return -1;
 		}
 		if ((gz = gzdopen(fd, "rb")) == NULL) {
-			mandoc_msg(MANDOCERR_FILE, 0, 0,
-			    "gzdopen: %s", strerror(errno));
+			mandoc_msg(MANDOCERR_GZDOPEN, 0, 0,
+			    "%s", strerror(errno));
 			close(fd);
-			return 0;
+			return -1;
 		}
 	} else
 		gz = NULL;
@@ -482,7 +481,7 @@ read_whole_file(struct mparse *curp, int fd, struct buf *fb, int *with_mmap)
 
 	*with_mmap = 0;
 	off = 0;
-	retval = 0;
+	retval = -1;
 	fb->sz = 0;
 	fb->buf = NULL;
 	for (;;) {
@@ -498,13 +497,13 @@ read_whole_file(struct mparse *curp, int fd, struct buf *fb, int *with_mmap)
 		    read(fd, fb->buf + (int)off, fb->sz - off);
 		if (ssz == 0) {
 			fb->sz = off;
-			retval = 1;
+			retval = 0;
 			break;
 		}
 		if (ssz == -1) {
 			if (curp->gzip)
 				(void)gzerror(gz, &gzerrnum);
-			mandoc_msg(MANDOCERR_FILE, 0, 0, "read: %s",
+			mandoc_msg(MANDOCERR_READ, 0, 0, "%s",
 			    curp->gzip && gzerrnum != Z_ERRNO ?
 			    zError(gzerrnum) : strerror(errno));
 			break;
@@ -513,10 +512,10 @@ read_whole_file(struct mparse *curp, int fd, struct buf *fb, int *with_mmap)
 	}
 
 	if (curp->gzip && (gzerrnum = gzclose(gz)) != Z_OK)
-		mandoc_msg(MANDOCERR_FILE, 0, 0, "gzclose: %s",
+		mandoc_msg(MANDOCERR_GZCLOSE, 0, 0, "%s",
 		    gzerrnum == Z_ERRNO ? strerror(errno) :
 		    zError(gzerrnum));
-	if (retval == 0) {
+	if (retval == -1) {
 		free(fb->buf);
 		fb->buf = NULL;
 	}
@@ -555,7 +554,7 @@ mparse_readfd(struct mparse *curp, int fd, const char *filename)
 		mandoc_msg(MANDOCERR_ROFFLOOP, curp->line, 0, NULL);
 		return;
 	}
-	if (read_whole_file(curp, fd, &blk, &with_mmap) == 0)
+	if (read_whole_file(curp, fd, &blk, &with_mmap) == -1)
 		return;
 
 	/*
diff --git a/usr.bin/mandoc/tag.c b/usr.bin/mandoc/tag.c
index 6ae6faa2a7e..df05a19885a 100644
--- a/usr.bin/mandoc/tag.c
+++ b/usr.bin/mandoc/tag.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: tag.c,v 1.21 2018/11/22 11:30:15 schwarze Exp $ */
+/*	$OpenBSD: tag.c,v 1.22 2019/07/10 19:38:56 schwarze Exp $ */
 /*
- * Copyright (c) 2015, 2016, 2018 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2015, 2016, 2018, 2019 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
@@ -16,7 +16,7 @@
  */
 #include <sys/types.h>
 
-#include <err.h>
+#include <errno.h>
 #include <limits.h>
 #include <signal.h>
 #include <stddef.h>
@@ -28,6 +28,7 @@
 
 #include "mandoc_aux.h"
 #include "mandoc_ohash.h"
+#include "mandoc.h"
 #include "tag.h"
 
 struct tag_entry {
@@ -79,8 +80,10 @@ tag_init(void)
 
 	/* Save the original standard output for use by the pager. */
 
-	if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1)
+	if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1) {
+		mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 		goto fail;
+	}
 
 	/* Create both temporary output files. */
 
@@ -88,12 +91,20 @@ tag_init(void)
 	    sizeof(tag_files.ofn));
 	(void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
 	    sizeof(tag_files.tfn));
-	if ((ofd = mkstemp(tag_files.ofn)) == -1)
+	if ((ofd = mkstemp(tag_files.ofn)) == -1) {
+		mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
+		    "%s: %s", tag_files.ofn, strerror(errno));
 		goto fail;
-	if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1)
+	}
+	if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1) {
+		mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
+		    "%s: %s", tag_files.tfn, strerror(errno));
 		goto fail;
-	if (dup2(ofd, STDOUT_FILENO) == -1)
+	}
+	if (dup2(ofd, STDOUT_FILENO) == -1) {
+		mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 		goto fail;
+	}
 	close(ofd);
 
 	/*
@@ -217,10 +228,11 @@ tag_write(void)
 		return;
 	if (tag_files.tagname != NULL && ohash_find(&tag_data,
             ohash_qlookup(&tag_data, tag_files.tagname)) == NULL) {
-		warnx("%s: no such tag", tag_files.tagname);
+		mandoc_msg(MANDOCERR_TAG, 0, 0, "%s", tag_files.tagname);
 		tag_files.tagname = NULL;
 	}
-	stream = fdopen(tag_files.tfd, "w");
+	if ((stream = fdopen(tag_files.tfd, "w")) == NULL)
+		mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
 	entry = ohash_first(&tag_data, &slot);
 	while (entry != NULL) {
 		if (stream != NULL && entry->prio >= 0)