From 48560d72cd675814d1d7718a9a44d2aea1ef6c79 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Barnab=C3=A1s=20P=C5=91cze?=
 <barnabas.pocze@ideasonboard.com>
Date: Fri, 25 Jul 2025 09:43:05 +0200
Subject: [PATCH] libcamera: base: {unique,shared}_fd: Warn if closing fails
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If the contained file descriptor cannot be successfully closed,
that is usually a sign of a more serious invariant violation,
which deserves attention, so report those cases.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
 src/libcamera/base/shared_fd.cpp | 7 +++++--
 src/libcamera/base/unique_fd.cpp | 8 ++++++--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/libcamera/base/shared_fd.cpp b/src/libcamera/base/shared_fd.cpp
index 7afc8ca5..81b703a8 100644
--- a/src/libcamera/base/shared_fd.cpp
+++ b/src/libcamera/base/shared_fd.cpp
@@ -284,8 +284,11 @@ SharedFD::Descriptor::Descriptor(int fd, bool duplicate)
 
 SharedFD::Descriptor::~Descriptor()
 {
-	if (fd_ != -1)
-		close(fd_);
+	if (fd_ >= 0 && close(fd_) < 0) {
+		int ret = -errno;
+		LOG(SharedFD, Error) << "Failed to close file descriptor "
+				     << fd_ << ": " << strerror(-ret);
+	}
 }
 
 } /* namespace libcamera */
diff --git a/src/libcamera/base/unique_fd.cpp b/src/libcamera/base/unique_fd.cpp
index d0649e4d..178c08c4 100644
--- a/src/libcamera/base/unique_fd.cpp
+++ b/src/libcamera/base/unique_fd.cpp
@@ -7,6 +7,7 @@
 
 #include <libcamera/base/unique_fd.h>
 
+#include <string.h>
 #include <unistd.h>
 #include <utility>
 
@@ -98,8 +99,11 @@ void UniqueFD::reset(int fd)
 
 	std::swap(fd, fd_);
 
-	if (fd >= 0)
-		close(fd);
+	if (fd >= 0 && close(fd) < 0) {
+		int ret = -errno;
+		LOG(UniqueFD, Error) << "Failed to close file descriptor "
+				     << fd << ": " << strerror(-ret);
+	}
 }
 
 /**