rust/ffi: JsonBuilder wrapper around C JsonBuilder API

For use by plugins that need to work with JsonBuilder.

rust/ffi/src/jsonbuilder.rs

@@ -0,0 +1,98 @@
+/* Copyright (C) 2026 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+//! Rust wrappers around the C JsonBuilder API.
+//!
+//! This is for plugin and library users.
+
+use std::ffi::{CString, NulError};
+
+use suricata_sys::sys::{
+    SCJbClose, SCJbOpenObject, SCJbSetFormatted, SCJbSetString, SCJsonBuilder,
+};
+
+// TODO: Map suricata::jsonbuilder::JsonBuilder errors as well,
+// however that will require extending that API to pass errors over
+// the FFI boundary as integer or strings.
+#[derive(Debug)]
+pub enum Error {
+    NulError(NulError),
+    Other,
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::NulError(err) => err.fmt(f),
+            Self::Other => write!(f, "error"),
+        }
+    }
+}
+
+impl std::error::Error for Error {}
+
+impl From<NulError> for Error {
+    fn from(err: NulError) -> Self {
+        Self::NulError(err)
+    }
+}
+
+pub struct JsonBuilder {
+    jb: *mut SCJsonBuilder,
+}
+
+impl JsonBuilder {
+    pub fn from_raw(jb: *mut SCJsonBuilder) -> Self {
+        Self { jb }
+    }
+
+    pub fn open_object(&mut self, key: &str) -> Result<&mut Self, Error> {
+        let key = CString::new(key)?;
+        if unsafe { SCJbOpenObject(self.jb, key.as_ptr()) } {
+            Ok(self)
+        } else {
+            Err(Error::Other)
+        }
+    }
+
+    pub fn set_string(&mut self, key: &str, val: &str) -> Result<&mut Self, Error> {
+        let key = CString::new(key)?;
+        let val = CString::new(val.escape_default().to_string())?;
+        if unsafe { SCJbSetString(self.jb, key.as_ptr(), val.as_ptr()) } {
+            Ok(self)
+        } else {
+            Err(Error::Other)
+        }
+    }
+
+    pub fn set_formatted(&mut self, formatted: &str) -> Result<&mut Self, Error> {
+        let formatted = CString::new(formatted)?;
+        if unsafe { SCJbSetFormatted(self.jb, formatted.as_ptr()) } {
+            Ok(self)
+        } else {
+            Err(Error::Other)
+        }
+    }
+
+    pub fn close(&mut self) -> Result<&mut Self, Error> {
+        if unsafe { SCJbClose(self.jb) } {
+            Ok(self)
+        } else {
+            Err(Error::Other)
+        }
+    }
+}

rust/ffi/src/lib.rs

@@ -17,4 +17,5 @@
 
 pub mod debug;
 pub mod eve;
+pub mod jsonbuilder;
 pub mod plugin;