From 1959e1c83899f52ef689bd559af329c2f788ac4a Mon Sep 17 00:00:00 2001
From: Mathieu Hofman <mathieu@agoric.com>
Date: Thu, 27 Apr 2023 21:25:43 +0000
Subject: [PATCH] feat: write snapshot to fd

---
 xsnap/sources/xsnap-worker.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/xsnap/sources/xsnap-worker.c b/xsnap/sources/xsnap-worker.c
index 78401c8..aa9f4ba 100644
--- a/xsnap/sources/xsnap-worker.c
+++ b/xsnap/sources/xsnap-worker.c
@@ -537,7 +537,17 @@ int main(int argc, char* argv[])
 			#endif
 				path = nsbuf + 1;
 				SnapshotStream stream;
-				stream.file = fopen(path, "wb");
+				if (path[0] == '@') {
+					int fd = atoi(path + 1);
+					int tmpfd = dup(fd);
+					if (tmpfd < 0) {
+						stream.file = NULL;
+					} else {
+						stream.file = fdopen(tmpfd, "ab");
+					}
+				} else {
+					stream.file = fopen(path, "wb");
+				}
 				stream.size = 0;
 				if (stream.file) {
 					snapshot.stream = &stream;