fix Rust linking

linux-user/main.c

@@ -581,6 +581,16 @@ static int parse_args(int argc, char **argv)
             r++;
         }
 
+        if (!strncmp(r, "libafl", 6)) {
+            if (optind >= argc) {
+                (void) fprintf(stderr,
+                    "qemu: missing argument for option '%s'\n", r);
+                exit(EXIT_FAILURE);
+            }
+            optind++;
+            continue;
+        }
+
         for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
             if (!strcmp(r, arginfo->argv)) {
                 if (arginfo->has_arg) {

qemu_libafl_bridge/.gitignore

@@ -0,0 +1,14 @@
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb

qemu_libafl_bridge/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "qemu_libafl_bridge"
-version = "0.1.0"
+version = "0.2.0"
 authors = ["Andrea Fioraldi <andreafioraldi@gmail.com>"]
 description = "QEMU and LibAFL bridge lib"
 repository = "https://github.com/AFLplusplus/qemu-libafl-bridge/"
@@ -13,3 +13,6 @@ edition = "2018"
 [dependencies]
 num = "0.4"
 num_enum = "0.5.1"
+
+[build-dependencies]
+cc = { version = "1.0" }

qemu_libafl_bridge/build.rs

@@ -0,0 +1,17 @@
+use std::{env, path::Path};
+
+fn main() {
+    let out_dir = env::var_os("OUT_DIR").unwrap();
+    let out_dir = out_dir.to_string_lossy().to_string();
+    let src_dir = Path::new("src");
+
+    println!("cargo:rerun-if-changed=src/weaks.c");
+
+    cc::Build::new()
+        .file(src_dir.join("weaks.c"))
+        .compile("weaks");
+
+    println!("cargo:rustc-link-search=native={}", &out_dir);
+
+    println!("cargo:rerun-if-changed=build.rs");
+}

qemu_libafl_bridge/src/lib.rs

@@ -89,4 +89,8 @@ impl QemuEmulator {
     pub fn h2g(&self, addr: isize) -> *mut u8 {
         unsafe { transmute(addr - guest_base) }
     }
+
+    pub fn new() -> Self {
+        Self {}
+    }
 }

qemu_libafl_bridge/src/weaks.c

@@ -0,0 +1,30 @@
+#include <stdlib.h>
+#include <stdint.h>
+
+__attribute__((weak)) int libafl_qemu_write_reg(int reg, uint8_t* val) {
+  (void)reg;
+  (void)val;
+  return 0;
+}
+
+__attribute__((weak)) int libafl_qemu_read_reg(int reg, uint8_t* val) {
+  (void)reg;
+  (void)val;
+  return 0;
+}
+
+__attribute__((weak)) int libafl_qemu_num_regs(void) {
+  return 0;
+}
+
+__attribute__((weak)) int libafl_qemu_set_breakpoint(uint64_t addr) {
+  (void)addr;
+  return 0;
+}
+
+__attribute__((weak)) int libafl_qemu_remove_breakpoint(uint64_t addr) {
+  (void)addr;
+  return 0;
+}
+
+__attribute__((weak)) size_t guest_base = 0;