Added support for prctl handling thread names

Author: YohDeadfall

src/tools/miri/ci/ci.sh

@@ -154,7 +154,7 @@ case $HOST_TARGET in
  TEST_TARGET=i686-unknown-freebsd run_tests_minimal $BASIC$UNIXtime hashmap random threadname pthread fs libc-pipe
  TEST_TARGET=x86_64-unknown-illumos run_tests_minimal $BASIC$UNIXtime hashmap random thread sync available-parallelism tls libc-pipe
  TEST_TARGET=x86_64-pc-solaris run_tests_minimal $BASIC$UNIXtime hashmap random thread sync available-parallelism tls libc-pipe
- TEST_TARGET=aarch64-linux-android run_tests_minimal $BASIC$UNIXtime hashmap pthread --skip threadname
+ TEST_TARGET=aarch64-linux-android run_tests_minimal $BASIC$UNIXtime hashmap threadname pthread
  TEST_TARGET=wasm32-wasip2 run_tests_minimal $BASIC wasm
  TEST_TARGET=wasm32-unknown-unknown run_tests_minimal no_std empty_main wasm # this target doesn't really have std
  TEST_TARGET=thumbv7em-none-eabihf run_tests_minimal no_std

src/tools/miri/src/shims/unix/android/foreign_items.rs

@@ -1,6 +1,7 @@
 use rustc_span::Symbol;
 use rustc_target::spec::abi::Abi;
 
+usecrate::shims::unix::android::thread::prctl;
 usecrate::*;
 
 pubfnis_dyn_sym(_name:&str) -> bool{
@@ -25,6 +26,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
  this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
 }
 
+// Threading
+"prctl" => prctl(this, link_name, abi, args, dest)?,
+
  _ => returninterp_ok(EmulateItemResult::NotSupported),
 }
 interp_ok(EmulateItemResult::NeedsReturn)

src/tools/miri/src/shims/unix/android/mod.rs

@@ -1 +1,2 @@
 pubmod foreign_items;
+pubmod thread;

src/tools/miri/src/shims/unix/android/thread.rs

@@ -0,0 +1,57 @@
+use rustc_span::Symbol;
+use rustc_target::abi::Size;
+use rustc_target::spec::abi::Abi;
+
+usecrate::helpers::check_min_arg_count;
+usecrate::shims::unix::thread::EvalContextExtas _;
+usecrate::*;
+
+constTASK_COMM_LEN:usize = 16;
+
+pubfnprctl<'tcx>(
+this:&mutMiriInterpCx<'tcx>,
+link_name:Symbol,
+abi:Abi,
+args:&[OpTy<'tcx>],
+dest:&MPlaceTy<'tcx>,
+) -> InterpResult<'tcx>{
+// We do not use `check_shim` here because `prctl` is variadic. The argument
+// count is checked bellow.
+ this.check_abi_and_shim_symbol_clash(abi,Abi::C{unwind:false}, link_name)?;
+
+// FIXME: Use constants once https://github.com/rust-lang/libc/pull/3941 backported to the 0.2 branch.
+let pr_set_name = 15;
+let pr_get_name = 16;
+
+let[op] = check_min_arg_count("prctl", args)?;
+let res = match this.read_scalar(op)?.to_i32()? {
+ op if op == pr_set_name => {
+let[_, name] = check_min_arg_count("prctl(PR_SET_NAME, ...)", args)?;
+let name = this.read_scalar(name)?;
+let thread = this.pthread_self()?;
+// The Linux kernel silently truncates long names.
+// https://www.man7.org/linux/man-pages/man2/PR_SET_NAME.2const.html
+let res =
+ this.pthread_setname_np(thread, name,TASK_COMM_LEN,/* truncate */true)?;
+assert!(res);
+Scalar::from_u32(0)
+}
+ op if op == pr_get_name => {
+let[_, name] = check_min_arg_count("prctl(PR_GET_NAME, ...)", args)?;
+let name = this.read_scalar(name)?;
+let thread = this.pthread_self()?;
+let len = Scalar::from_target_usize(TASK_COMM_LENasu64, this);
+ this.check_ptr_access(
+ name.to_pointer(this)?,
+Size::from_bytes(TASK_COMM_LEN),
+CheckInAllocMsg::MemoryAccessTest,
+)?;
+let res = this.pthread_getname_np(thread, name, len,/* truncate*/false)?;
+assert!(res);
+Scalar::from_u32(0)
+}
+ op => throw_unsup_format!("Miri does not support `prctl` syscall with op={}", op),
+};
+ this.write_scalar(res, dest)?;
+interp_ok(())
+}

src/tools/miri/src/shims/unix/freebsd/foreign_items.rs

@@ -29,6 +29,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
  this.read_scalar(thread)?,
  this.read_scalar(name)?,
  max_len,
+/* truncate */false,
 )?;
 }
 "pthread_get_name_np" => {

src/tools/miri/src/shims/unix/linux/foreign_items.rs

@@ -84,6 +84,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
  this.read_scalar(thread)?,
  this.read_scalar(name)?,
 TASK_COMM_LEN,
+/* truncate */false,
 )?;
 let res = if res {Scalar::from_u32(0)}else{ this.eval_libc("ERANGE")};
  this.write_scalar(res, dest)?;

src/tools/miri/src/shims/unix/macos/foreign_items.rs

@@ -181,6 +181,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
  thread,
  this.read_scalar(name)?,
  this.eval_libc("MAXTHREADNAMESIZE").to_target_usize(this)?.try_into().unwrap(),
+/* truncate */false,
 )? {
 Scalar::from_u32(0)
 }else{

src/tools/miri/src/shims/unix/solarish/foreign_items.rs

@@ -30,6 +30,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
  this.read_scalar(thread)?,
  this.read_scalar(name)?,
  max_len,
+/* truncate */false,
 )?;
 let res = if res {Scalar::from_u32(0)}else{ this.eval_libc("ERANGE")};
  this.write_scalar(res, dest)?;

src/tools/miri/src/shims/unix/thread.rs

@@ -64,23 +64,29 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 }
 
 /// Set the name of the specified thread. If the name including the null terminator
-/// is longer than `name_max_len`, then `false` is returned.
+/// is longer or equals to `name_max_len`, then if `truncate` is set the truncated name
+/// is used as the thread name, otherwise `false` is returned.
 fnpthread_setname_np(
 &mutself,
 thread:Scalar,
 name:Scalar,
 name_max_len:usize,
+truncate:bool,
 ) -> InterpResult<'tcx,bool>{
 let this = self.eval_context_mut();
 
 let thread = thread.to_int(this.libc_ty_layout("pthread_t").size)?;
 let thread = ThreadId::try_from(thread).unwrap();
 let name = name.to_pointer(this)?;
-let name = this.read_c_str(name)?.to_owned();
+letmutname = this.read_c_str(name)?.to_owned();
 
 // Comparing with `>=` to account for null terminator.
 if name.len() >= name_max_len {
-returninterp_ok(false);
+if truncate {
+ name.truncate(name_max_len.saturating_sub(1));
+}else{
+returninterp_ok(false);
+}
 }
 
  this.set_thread_name(thread, name);

src/tools/miri/test_dependencies/Cargo.lock

@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "addr2line"
@@ -128,9 +128,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.158"
+version = "0.2.161"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d8adc4bb1803a324070e64a98ae98f38934d91957a99cfb3a43dcbc01bc56439"
+checksum = "8e9489c2807c139ffd9c1794f4af0ebe86a828db53ecdc7fea2111d0fed085d1"
 
 [[package]]
 name = "linux-raw-sys"