From fafd9712e7435edce99495a6ead3f82229f28653 Mon Sep 17 00:00:00 2001
From: Lars Erik Wik <lars.erik.wik@northern.tech>
Date: Fri, 29 Nov 2024 11:35:22 +0100
Subject: [PATCH] CFEngine no longer relies on `rs_file_size()`

Apparently `rs_file_size()` does not exist (or is not exposed) in
previous versions of `librsync`. Hence, we'll make our own
implementation in order to make the File Stream API a bit more backwards
compatible in terms of `librsync` versions.

Ticket: ENT-12414
Changelog: None
Signed-off-by: Lars Erik Wik <lars.erik.wik@northern.tech>
---
 configure.ac           |  2 +-
 libcfnet/file_stream.c | 27 ++++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 363e0b6b36..786110371d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -531,7 +531,7 @@ fi
 
 CF3_WITH_LIBRARY(librsync, [
     AC_CHECK_HEADERS([librsync.h], [], AC_MSG_ERROR(Cannot find librsync))
-    AC_CHECK_LIB(rsync, rs_file_size, [], [AC_MSG_ERROR(Cannot find librsync)])
+    AC_CHECK_LIB(rsync, rs_job_iter, [], [AC_MSG_ERROR(Cannot find librsync)])
   ]
 )
 
diff --git a/libcfnet/file_stream.c b/libcfnet/file_stream.c
index ea35caa0ed..4d9237fbc9 100644
--- a/libcfnet/file_stream.c
+++ b/libcfnet/file_stream.c
@@ -592,6 +592,31 @@ bool FileStreamServe(SSL *conn, const char *filename)
 
 #define ERROR_MSG_INTERNAL_CLIENT_ERROR "Internal client error"
 
+
+/**
+ * @brief Get the size of a file
+ *
+ * @param file The file pointer
+ * @return the file size or -1 on error
+ * @note -1 on error is quite handy, because rs_sig_args() iterprets it as
+ *       unknown file size
+ */
+static rs_long_t GetFileSize(FILE *file)
+{
+    int fd = fileno(file);
+    if (fd == -1) {
+        return -1;
+    }
+
+    struct stat sb;
+    if (fstat(fd, &sb) == -1)
+    {
+        return -1;
+    }
+
+    return S_ISREG(sb.st_mode);
+}
+
 /**
  * @brief Compute and send a signature of the basis file
  *
@@ -621,7 +646,7 @@ static bool SendSignature(SSL *conn, const char *filename)
     }
 
     /* Get file size */
-    rs_long_t fsize = rs_file_size(file);
+    rs_long_t fsize = GetFileSize(file);
 
     /* Get recommended arguments */
     rs_magic_number sig_magic = 0;