From 1ce4ec34c05a6a58f229dc231664ba66875598bc Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Thu, 25 Apr 2019 18:23:49 -0400
Subject: fopen(), fclose(): Replace echo, improve eval safety

---
diff --git a/src/fd.sh b/src/fd.sh
index 8bd4584..45b1423 100644
--- a/src/fd.sh
+++ b/src/fd.sh
@@ -57,7 +57,8 @@ fopen()
 	# Find first available file descriptor.
 	i=${_FD_MIN}
 	while [ ${i} -le ${_FD_MAX} ]; do
-		if [ "x$(eval echo "\${_fd_${i}+set}")" != 'xset' ]; then
+		if [ "x$(eval "printf '%s' \"\${_fd_${i}+set}\"")" != 'xset' ]
+		then
 			fd=${i}
 			break
 		fi
@@ -68,8 +69,8 @@ fopen()
 		return 1
 	fi
 
-	if eval "exec ${fd}${mode}'${path}'"; then
-		eval "_fd_${fd}='${mode}${path}'"
+	if eval "exec ${fd}${mode}\"\${path}\""; then
+		eval "_fd_${fd}=\"\${mode}\${path}\""
 		FD="${fd}"
 		return 0
 	else
@@ -84,7 +85,7 @@ fclose()
 	shift 1
 
 	# Make sure the file descriptor is open.
-	if [ "x$(eval echo "\${_fd_${fd}+set}")" != 'xset' ]; then
+	if [ "x$(eval "printf '%s' \"\${_fd_${fd}+set}\"")" != 'xset' ]; then
 		error "$(get_msg 'ebadf')"
 		return 1
 	fi
--
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