From 1deaab39a80036118924ab4e446d4aa10f03ade9 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <steinar+nageru@gunderson.no>
Date: Tue, 30 Apr 2024 21:47:11 +0200
Subject: [PATCH] In v4l2proxy, check the return value of write().

This gives both support for partial writes, better error handling,
and resilience against EINTR.
---
 v4l2proxy.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/v4l2proxy.cpp b/v4l2proxy.cpp
index 4e0b36b..7ead4aa 100644
--- a/v4l2proxy.cpp
+++ b/v4l2proxy.cpp
@@ -12,6 +12,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <errno.h>
 #include <sys/ioctl.h>
 #include <linux/videodev2.h>
 #include <bmusb/bmusb.h>
@@ -84,7 +85,20 @@ void frame_callback(uint16_t timecode,
 		}
 #endif
 
-		write(video_fd, origptr, video_frame.len);
+		size_t len = video_frame.len;
+		while (len > 0) {
+			ssize_t ret = write(video_fd, origptr, len);
+			if (ret == -1) {
+				if (errno == EINTR) {
+					continue;
+				} else {
+					perror("write");
+					break;  // Hope for better luck next frame.
+				}
+			}
+			origptr += ret;
+			len -= ret;
+		}
 	}
 
 	usb->get_video_frame_allocator()->release_frame(video_frame);
-- 
2.39.5