From: Jan Hák <jan.hak@nic.cz>
Date: Thu, 18 Sep 2025 09:01:11 +0000 (+0200)
Subject: contrib/files: fix stream error handling (clang analyzer)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=771c64c5a3ed2dbec0ea86732304806021ceb9ae;p=thirdparty%2Fknot-dns.git

contrib/files: fix stream error handling (clang analyzer)

POSIX / fread():
The file position indicator for the stream (if defined) shall be advanced by the
number of bytes successfully read. If an error occurs, the resulting value of
the file position indicator for the stream is unspecified. If a partial element
is read, its value is unspecified.
---

diff --git a/src/contrib/files.c b/src/contrib/files.c
index 9fef720014..89a8186762 100644
--- a/src/contrib/files.c
+++ b/src/contrib/files.c
@@ -224,9 +224,11 @@ int copy_file(const char *dest, const char *src)
 		goto done;
 	}
 
-	ssize_t cnt;
+	assert(ret == 0);
+	size_t cnt;
 	while ((cnt = fread(buf, sizeof(*buf), BUFSIZE, from)) != 0 &&
-	       (ret = (fwrite(buf, sizeof(*buf), cnt, file) == cnt))) {
+	       (ret = (fwrite(buf, sizeof(*buf), cnt, file) == cnt)) &&
+	       (feof(from) | ferror(from)) == 0) {
 	}
 
 	ret = !ret || ferror(from);