Move the full responsibility for reporting open(2) errors from

mparse_open() to the caller.  That is better because only the caller
knows its preferred reporting method and format and only the caller
has access to all the data that should be included - like the column
number in .so processing or the current manpath in makewhatis(8).
Moving the mandoc_msg() call out is possible because the caller can
call strerror(3) just as easily as mparse_open() can.

Move mandoc_msg_setinfilename() closer to the parsing of the file
contents, to avoid problems *with* the file (like non-existence,
lack of permissions, etc.) getting misreported as problems *in*
the file.

Fix the column number reported for .so failure:
let it point to the beginning of the filename.

Taken together, this prevents makewhatis(8) from spewing confusing
messages about .so failures to stderr, a bug reported by
Raf Czlonka <rczlonka at gmail dot com> on ports@.

It also prevents mandoc(1) from issuing *two* messages for every
single .so failure.

2 files changed, 10 insertions, 8 deletions

diff --git a/usr.bin/mandoc/main.c b/usr.bin/mandoc/main.c
index 8fd47eb38f7..47c989073ad 100644
--- a/usr.bin/mandoc/main.c
+++ b/usr.bin/mandoc/main.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: main.c,v 1.216 2018/12/14 05:17:45 schwarze Exp $ */
+/*	$OpenBSD: main.c,v 1.217 2018/12/20 21:27:51 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2012, 2014-2018 Ingo Schwarze <schwarze@openbsd.org>
@@ -480,7 +480,6 @@ main(int argc, char *argv[])
 		} else
 			thisarg = *argv;
 
-		mandoc_msg_setinfilename(thisarg);
 		fd = mparse_open(curp.mp, thisarg);
 		if (fd != -1) {
 			if (use_pager) {
@@ -493,11 +492,13 @@ main(int argc, char *argv[])
 					    conf.output.tag : *argv;
 			}
 
+			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);
 
 			if (ferror(stdout)) {
 				if (tag_files != NULL) {
@@ -515,8 +516,9 @@ main(int argc, char *argv[])
 					outdata_alloc(&curp);
 				terminal_sepline(curp.outdata);
 			}
-		}
-		mandoc_msg_setinfilename(NULL);
+		} else
+			mandoc_msg(MANDOCERR_FILE, 0, 0,
+			    "%s", strerror(errno));
 
 		if (curp.wstop && mandoc_msg_getrc() != MANDOCLEVEL_OK)
 			break;
diff --git a/usr.bin/mandoc/read.c b/usr.bin/mandoc/read.c
index 2cb4b29a478..dae214b2d51 100644
--- a/usr.bin/mandoc/read.c
+++ b/usr.bin/mandoc/read.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: read.c,v 1.178 2018/12/14 06:33:03 schwarze Exp $ */
+/*	$OpenBSD: read.c,v 1.179 2018/12/20 21:27:51 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2018 Ingo Schwarze <schwarze@openbsd.org>
@@ -370,8 +370,9 @@ rerun:
 				mparse_readfd(curp, fd, ln.buf + of);
 				close(fd);
 			} else {
-				mandoc_msg(MANDOCERR_SO_FAIL, curp->line,
-				    pos, ".so %s", ln.buf + of);
+				mandoc_msg(MANDOCERR_SO_FAIL,
+				    curp->line, of, ".so %s: %s",
+				    ln.buf + of, strerror(errno));
 				ln.sz = mandoc_asprintf(&cp,
 				    ".sp\nSee the file %s.\n.sp",
 				    ln.buf + of);
@@ -631,7 +632,6 @@ mparse_open(struct mparse *curp, const char *file)
 
 	/* Neither worked, give up. */
 
-	mandoc_msg(MANDOCERR_FILE, 0, 0, "%s", strerror(errno));
 	return -1;
 }