Fix mandoc_normdate() and the way it is used.

In the past, it could return NULL but the calling code wasn't prepared
to handle that.  Make sure it always returns an allocated string.
While here, simplify the code by handling the "quick" attribute
inside mandoc_normdate() rather than at multiple callsites.

Triggered by deraadt@ pointing out
that snprintf(3) error handling was incomplete in time2a().

3 files changed, 23 insertions, 32 deletions

diff --git a/man_validate.c b/man_validate.c
index 55ac13a8..421a4843 100644
--- a/man_validate.c
+++ b/man_validate.c
@@ -185,8 +185,7 @@ check_root(CHKARGS)
 
 		man->meta.title = mandoc_strdup("");
 		man->meta.msec = mandoc_strdup("");
-		man->meta.date = man->quick ? mandoc_strdup("") :
-		    mandoc_normdate(man, NULL, n->line, n->pos);
+		man->meta.date = mandoc_normdate(man, NULL, n->line, n->pos);
 	}
 
 	if (man->meta.os_e &&
@@ -369,8 +368,8 @@ post_TH(CHKARGS)
 	/* ->TITLE<- MSEC DATE OS VOL */
 
 	n = n->child;
-	if (n && n->string) {
-		for (p = n->string; '\0' != *p; p++) {
+	if (n != NULL && n->string != NULL) {
+		for (p = n->string; *p != '\0'; p++) {
 			/* Only warn about this once... */
 			if (isalpha((unsigned char)*p) &&
 			    ! isupper((unsigned char)*p)) {
@@ -388,9 +387,9 @@ post_TH(CHKARGS)
 
 	/* TITLE ->MSEC<- DATE OS VOL */
 
-	if (n)
+	if (n != NULL)
 		n = n->next;
-	if (n && n->string)
+	if (n != NULL && n->string != NULL)
 		man->meta.msec = mandoc_strdup(n->string);
 	else {
 		man->meta.msec = mandoc_strdup("");
@@ -400,17 +399,16 @@ post_TH(CHKARGS)
 
 	/* TITLE MSEC ->DATE<- OS VOL */
 
-	if (n)
+	if (n != NULL)
 		n = n->next;
-	if (n && n->string && '\0' != n->string[0]) {
-		man->meta.date = man->quick ?
-		    mandoc_strdup(n->string) :
-		    mandoc_normdate(man, n->string, n->line, n->pos);
-	} else {
+	if (n != NULL && n->string != NULL && n->string[0] != '\0')
+		man->meta.date = mandoc_normdate(man,
+		    n->string, n->line, n->pos);
+	else {
 		man->meta.date = mandoc_strdup("");
 		mandoc_msg(MANDOCERR_DATE_MISSING,
-		    n ? n->line : nb->line,
-		    n ? n->pos : nb->pos, "TH");
+		    n == NULL ? nb->line : n->line,
+		    n == NULL ? nb->pos : n->pos, "TH");
 	}
 
 	/* TITLE MSEC DATE ->OS<- VOL */
diff --git a/mandoc.c b/mandoc.c
index 434d5d93..46cedc67 100644
--- a/mandoc.c
+++ b/mandoc.c
@@ -494,9 +494,10 @@ time2a(time_t t)
 	size_t		 ssz;
 	int		 isz;
 
+	buf = NULL;
 	tm = localtime(&t);
 	if (tm == NULL)
-		return NULL;
+		goto fail;
 
 	/*
 	 * Reserve space:
@@ -520,7 +521,8 @@ time2a(time_t t)
 	 * of looking at LC_TIME.
 	 */
 
-	if ((isz = snprintf(p, 4 + 1, "%d, ", tm->tm_mday)) == -1)
+	isz = snprintf(p, 4 + 1, "%d, ", tm->tm_mday);
+	if (isz < 0 || isz > 4)
 		goto fail;
 	p += isz;
 
@@ -530,7 +532,7 @@ time2a(time_t t)
 
 fail:
 	free(buf);
-	return NULL;
+	return mandoc_strdup("");
 }
 
 char *
@@ -539,6 +541,9 @@ mandoc_normdate(struct roff_man *man, char *in, int ln, int pos)
 	char		*cp;
 	time_t		 t;
 
+	if (man->quick)
+		return mandoc_strdup(in == NULL ? "" : in);
+
 	/* No date specified: use today's date. */
 
 	if (in == NULL || *in == '\0')
diff --git a/mdoc_validate.c b/mdoc_validate.c
index 14fbf828..ef2df798 100644
--- a/mdoc_validate.c
+++ b/mdoc_validate.c
@@ -1903,8 +1903,7 @@ post_root(POST_ARGS)
 	/* Add missing prologue data. */
 
 	if (mdoc->meta.date == NULL)
-		mdoc->meta.date = mdoc->quick ? mandoc_strdup("") :
-		    mandoc_normdate(mdoc, NULL, 0, 0);
+		mdoc->meta.date = mandoc_normdate(mdoc, NULL, 0, 0);
 
 	if (mdoc->meta.title == NULL) {
 		mandoc_msg(MANDOCERR_DT_NOTITLE, 0, 0, "EOF");
@@ -2519,21 +2518,10 @@ post_dd(POST_ARGS)
 		mandoc_msg(MANDOCERR_PROLOG_ORDER,
 		    n->line, n->pos, "Dd after Os");
 
-	if (n->child == NULL || n->child->string[0] == '\0') {
-		mdoc->meta.date = mdoc->quick ? mandoc_strdup("") :
-		    mandoc_normdate(mdoc, NULL, n->line, n->pos);
-		return;
-	}
-
 	datestr = NULL;
 	deroff(&datestr, n);
-	if (mdoc->quick)
-		mdoc->meta.date = datestr;
-	else {
-		mdoc->meta.date = mandoc_normdate(mdoc,
-		    datestr, n->line, n->pos);
-		free(datestr);
-	}
+	mdoc->meta.date = mandoc_normdate(mdoc, datestr, n->line, n->pos);
+	free(datestr);
 }
 
 static void