[PATCH 2/2] paranoid safety fix to clamp pathnames to PATH_MAX

[Eric Wong <e@80x24.org>]

While I doubt Ruby (nor Perl) would store pathnames longer than
PATH_MAX by default, it's possible `eval' users to specify
whatever path (and line number) they wish to use.

Likely was the case with `# line $FILE' directives in Perl5
which prompted this clamping.
---
 ext/mwrap/mwrap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ext/mwrap/mwrap.c b/ext/mwrap/mwrap.c
index 90f560e..08761d6 100644
--- a/ext/mwrap/mwrap.c
+++ b/ext/mwrap/mwrap.c
@@ -470,6 +470,8 @@ static struct src_loc *update_stats_rcu_lock(size_t size, uintptr_t caller)
 
 		/* avoid vsnprintf or anything which could call malloc here: */
 		len = strlen(ptr);
+		if (len > PATH_MAX)
+			len = PATH_MAX;
 		k = (void *)kbuf;
 		k->total = size;
 		dst = mempcpy(k->k, ptr, len);