libnoaslr: add FreeBSD support (#1361)

utils/noaslr/libnoaslr/Cargo.toml

@@ -14,3 +14,6 @@ crate-type = ["dylib"]
 anyhow = { version = "1.0.71", default-features = false }
 ctor = { version = "0.2.2", default-features = false }
 nix = { version = "0.26.2", default-features = false, features = ["process", "personality"] }
+
+[target.'cfg(target_os = "freebsd")'.dependencies]
+libc = "0.2" 

utils/noaslr/libnoaslr/src/lib.rs

@@ -1,3 +1,8 @@
+#[cfg(not(any(target_os = "linux", target_os = "android")))]
+use {
+    anyhow::{anyhow, Result},
+    ctor::ctor,
+};
 #[cfg(any(target_os = "linux", target_os = "android"))]
 use {
     anyhow::{anyhow, Result},
@@ -39,7 +44,65 @@ fn libnoaslr() -> Result<()> {
     Ok(())
 }
 
-#[cfg(any(target_os = "linux", target_os = "android"))]
+#[cfg(target_os = "freebsd")]
+fn libnoaslr() -> Result<()> {
+    extern "C" {
+        fn exect(
+            c: *const libc::c_char,
+            args: *const *const libc::c_char,
+            env: *const *const libc::c_char,
+        ) -> libc::c_int;
+    }
+    let mut status = libc::PROC_ASLR_FORCE_DISABLE;
+    let mut pargs: Vec<i8> = vec![0; 256];
+    let mut penv: Vec<i8> = vec![0; 256];
+    let mut s = pargs.len();
+    let mib = &mut [libc::CTL_KERN, libc::KERN_PROC, libc::KERN_PROC_ARGS, -1];
+    let miblen = mib.len() as u32;
+    unsafe {
+        if libc::procctl(
+            libc::P_PID,
+            0,
+            libc::PROC_ASLR_CTL,
+            &mut status as *mut i32 as *mut libc::c_void,
+        ) < 0
+        {
+            return Err(anyhow!("Failed to set aslr control"));
+        }
+        if libc::sysctl(
+            mib.as_mut_ptr(),
+            miblen,
+            pargs.as_mut_ptr() as _,
+            &mut s,
+            std::ptr::null_mut(),
+            0,
+        ) < 0
+        {
+            return Err(anyhow!("Failed to get argv"));
+        }
+        pargs.set_len(s - 1);
+        let args = pargs.as_mut_ptr();
+        let mut env = std::ptr::null_mut();
+        mib[2] = libc::KERN_PROC_ENV;
+        s = penv.len();
+        if libc::sysctl(
+            mib.as_mut_ptr(),
+            miblen,
+            penv.as_mut_ptr() as _,
+            &mut s,
+            std::ptr::null_mut(),
+            0,
+        ) == 0
+        {
+            penv.set_len(s - 1);
+            env = penv.as_mut_ptr() as _;
+        }
+        exect(args.add(0) as _, args as _, env);
+    }
+    Ok(())
+}
+
+#[cfg(any(target_os = "linux", target_os = "android", target_os = "freebsd"))]
 #[ctor]
 fn init() {
     libnoaslr().unwrap();