Merge pull request RustPython#2031 from BolunThompson/no_follow_symlink

coolreader18 · web-flow · commit c23f279ca32c · 2020-07-31T12:11:23.000-05:00
Fixed bug where sys.executable may follow symlinks
diff --git a/Lib/test/test_sys_executable.py b/Lib/test/test_sys_executable.py
@@ -0,0 +1,62 @@
+import unittest
+import subprocess
+import sys
+import os
+
+# These should go into a test_sys.py file, but given these are the only
+# ones being tested currently that seems unnecessary.
+
+
+class SysExecutableTest(unittest.TestCase):
+
+    # This is a copy of test.test_sys.SysModuleTest.test_executable from cpython.
+    def cpython_tests(self):
+        # sys.executable should be absolute
+        self.assertEqual(os.path.abspath(sys.executable), sys.executable)
+
+        # Issue #7774: Ensure that sys.executable is an empty string if argv[0]
+        # has been set to a non existent program name and Python is unable to
+        # retrieve the real program name
+
+        # For a normal installation, it should work without 'cwd'
+        # argument. For test runs in the build directory, see #7774.
+        python_dir = os.path.dirname(os.path.realpath(sys.executable))
+        p = subprocess.Popen(
+            [
+                "nonexistent",
+                "-c",
+                'import sys; print(sys.executable.encode("ascii", "backslashreplace"))',
+            ],
+            executable=sys.executable,
+            stdout=subprocess.PIPE,
+            cwd=python_dir,
+        )
+        stdout = p.communicate()[0]
+        executable = stdout.strip().decode("ASCII")
+        p.wait()
+        self.assertIn(
+            executable,
+            ["b''", repr(sys.executable.encode("ascii", "backslashreplace"))],
+        )
+
+    def test_no_follow_symlink(self):
+        paths = [os.path.abspath("test_symlink"), "./test_symlink"]
+        for path in paths:
+            with self.subTest(path=path):
+                os.symlink(sys.executable, path)
+                command = [
+                    path,
+                    "-c",
+                    "import sys; print(sys.executable, end='')",
+                ]
+                try:
+                    process = subprocess.run(command, capture_output=True)
+                finally:
+                    os.remove(path)
+                self.assertEqual(
+                    os.path.abspath(path), process.stdout.decode("utf-8")
+                )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/vm/src/sysmodule.rs b/vm/src/sysmodule.rs
@@ -1,4 +1,4 @@
-use std::{env, mem};
+use std::{env, mem, path};
 
 use crate::builtins;
 use crate::frame::FrameRef;
@@ -28,9 +28,18 @@ fn argv(vm: &VirtualMachine) -> PyObjectRef {
 }
 
 fn executable(ctx: &PyContext) -> PyObjectRef {
-    if let Ok(path) = env::current_exe() {
-        if let Ok(path) = path.into_os_string().into_string() {
-            return ctx.new_str(path);
+    if let Some(exec_path) = env::args().next() {
+        if path::Path::new(&exec_path).is_absolute() {
+            return ctx.new_str(exec_path);
+        }
+        if let Ok(dir) = env::current_dir() {
+            if let Ok(dir) = dir.into_os_string().into_string() {
+                return ctx.new_str(format!(
+                    "{}/{}",
+                    dir,
+                    exec_path.strip_prefix("./").unwrap_or(&exec_path)
+                ));
+            }
         }
     }
     ctx.none()
