ci(runner): preserve rustup multicall invocation name

Keep the rustup PATH alias instead of invoking its rustup-init target directly. Audit resolved target bytes and recheck them before invocation; add a regression reproducing symlink-based CLI dispatch.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

scripts/ci/pi-intel/test_ci_helpers.py

@@ -1,14 +1,16 @@
 import os
 from pathlib import Path
 import shutil
+import subprocess
 import tarfile
 import tempfile
 import unittest
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 from lifecycle import CleanupUncertain, Lifecycle, run_test_cases
 from retain_pack import retain_pack
 from source_guard import tree, sha
 from admit_evidence import admit_evidence, regular_bytes
+from verify import tool_invocation, verify_tool_invocation
 
 class CleanupRegression(unittest.TestCase):
     def test_first_cleanup_failure_prevents_second_test_and_scratch_removal(self):
@@ -86,4 +88,24 @@ class ArtifactStorageRegression(unittest.TestCase):
             root=Path(root); (root/'escape').symlink_to('/etc/hosts')
             with self.assertRaisesRegex(RuntimeError, 'symlink'): admit_evidence(root)
 
+class MulticallInvocationRegression(unittest.TestCase):
+    def test_symlink_dispatched_cli_keeps_invocation_name_and_audits_target(self):
+        with tempfile.TemporaryDirectory() as root:
+            root=Path(root); target=root/'rustup-init'; invocation=root/'rustup'
+            target.write_text('#!/bin/sh\ncase "$0" in */rustup) test "$1" = toolchain; exit $?;; *) exit 2;; esac\n')
+            target.chmod(0o755); invocation.symlink_to(target.name)
+            with patch('verify.shutil.which', return_value=str(invocation)):
+                executable,audit=tool_invocation('rustup')
+            self.assertEqual(executable,invocation)
+            self.assertEqual(audit['resolvedTarget'],str(target.resolve()))
+            self.assertEqual(audit['targetSha256'],sha(target))
+            verify_tool_invocation(executable,audit)
+            clean={'PATH':'/usr/bin:/bin'}
+            self.assertEqual(subprocess.run([executable,'toolchain','install','1.97.1'],env=clean,timeout=5).returncode,0)
+            # This reproduces the CI failure: resolving the alias changes multicall mode.
+            self.assertEqual(subprocess.run([executable.resolve(),'toolchain','install','1.97.1'],env=clean,timeout=5).returncode,2)
+            target.write_text('#!/bin/sh\nexit 0\n')
+            with self.assertRaisesRegex(RuntimeError,'target bytes changed'):
+                verify_tool_invocation(executable,audit)
+
 if __name__ == '__main__': unittest.main()

scripts/ci/pi-intel/verify.py

@@ -15,6 +15,19 @@ SOURCE=PIN['sourceRevision']
 sha=source_guard.sha
 require=source_guard.require
 
+def tool_invocation(name):
+    found=shutil.which(name)
+    require(found is not None,'Required executable not found: '+name)
+    # Multicall CLIs dispatch on argv[0]; preserve the name returned by PATH lookup.
+    invocation=Path(found).absolute()
+    target=invocation.resolve(strict=True)
+    require(invocation.name==name and target.is_file() and os.access(invocation,os.X_OK),'Unexpected executable invocation')
+    return invocation, {'invocationPath':str(invocation),'resolvedTarget':str(target),'targetSha256':sha(target)}
+
+def verify_tool_invocation(invocation, audit):
+    require(str(invocation)==audit['invocationPath'] and str(invocation.resolve(strict=True))==audit['resolvedTarget'], 'Executable invocation or target changed')
+    require(sha(invocation.resolve(strict=True))==audit['targetSha256'],'Executable target bytes changed')
+
 def execute(args):
     stage=args.source.resolve(strict=True);out=args.output.resolve()
     out.mkdir(mode=0o700,parents=True,exist_ok=False)
@@ -31,7 +44,8 @@ def execute(args):
     inherited_path=os.environ['PATH']
     node=Path(shutil.which('node')).resolve(strict=True)
     pnpm=Path(shutil.which('pnpm')).resolve(strict=True)
-    rustup=Path(shutil.which('rustup')).resolve(strict=True)
+    rustup,rustup_audit=tool_invocation('rustup')
+    receipt['rustupTool']=rustup_audit;save()
     env={'PATH':inherited_path,'HOME':str(scratch/'home'),'TMPDIR':str(scratch),'LANG':'en_US.UTF-8','CI':'true',
          'PAPERCLIP_TELEMETRY_ENABLED':'false','PAPERCLIP_RUNNER_SOURCE_REVISION':SOURCE,
          'CARGO_HOME':str(scratch/'cargo'),'RUSTUP_HOME':str(scratch/'rustup'),'CARGO_TARGET_DIR':str(scratch/'target'),
@@ -43,6 +57,7 @@ def execute(args):
     signal.signal(signal.SIGTERM,stop_signal)
     def run(command,label,timeout,cwd=stage,command_env=None,owned=False):
         nonlocal active,owner
+        if str(command[0])==str(rustup):verify_tool_invocation(rustup,rustup_audit)
         lifecycle.begin()
         row={'label':label,'startedAt':datetime.datetime.now(datetime.timezone.utc).isoformat(),'command':list(map(str,command)),'deadlineSeconds':timeout,'status':'running'}
         receipt['commands'].append(row);save();start=time.monotonic()