Merge pull request #3627 from laloch/argv0

Set argv[0] of a subprocess to the command as inserted by the user

news/argv0.rst

@@ -0,0 +1,26 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* Xonsh now launches subprocesses with their ``argv[0]`` argument containing
+  the command exactly as inserted by the user instead of setting it to the
+  resolved path of the executable. This is for consistency with bash and other
+  shells.
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

tests/bin/checkargv0.xsh

@@ -0,0 +1,25 @@
+#!/usr/bin/env xonsh
+res = True
+script = """import os
+path = "/proc/{}/cmdline".format(os.getpid())
+with open(path, "r") as f:
+    lines = f.read().split("\x00")
+    print(lines[0])"""
+
+def check(python):
+    argv0 = $(@(python) -c @(script)).rstrip()
+
+    if argv0 == python:
+        return True
+
+    print("Unexpected argv[0]: {} != {}".format(argv0, python))
+    return False
+
+
+python = "python"
+res &= check(python)
+
+python = $(which -s python)
+res &= check(python)
+if res:
+    print("OK")

tests/test_integrations.py

@@ -10,7 +10,9 @@ import xonsh
 from xonsh.lib.os import indir
 
 from tools import (
+    skip_if_on_msys,
     skip_if_on_windows,
+    skip_if_on_darwin,
     ON_WINDOWS,
     ON_DARWIN,
     ON_TRAVIS,
@@ -681,3 +683,10 @@ aliases['echo'] = _echo
 def test_single_command_return_code(cmd, exp_rtn):
     _, _, rtn = run_xonsh(cmd, single_command=True)
     assert rtn == exp_rtn
+
+
+@skip_if_on_msys
+@skip_if_on_windows
+@skip_if_on_darwin
+def test_argv0():
+    check_run_xonsh("checkargv0.xsh", None, "OK\n")

xonsh/built_ins.py

@@ -206,8 +206,9 @@ def _un_shebang(x):
 
 def get_script_subproc_command(fname, args):
     """Given the name of a script outside the path, returns a list representing
-    an appropriate subprocess command to execute the script.  Raises
-    PermissionError if the script is not executable.
+    an appropriate subprocess command to execute the script or None if
+    the argument is not readable or not a script. Raises PermissionError
+    if the script is not executable.
     """
     # make sure file is executable
     if not os.access(fname, os.X_OK):
@@ -217,10 +218,10 @@ def get_script_subproc_command(fname, args):
         # execute permissions but not read/write permissions. This enables
         # things with the SUID set to be run. Needs to come before _is_binary()
         # is called, because that function tries to read the file.
-        return [fname] + args
+        return None
     elif _is_binary(fname):
         # if the file is a binary, we should call it directly
-        return [fname] + args
+        return None
     if ON_WINDOWS:
         # Windows can execute various filetypes directly
         # as given in PATHEXT
@@ -730,7 +731,9 @@ class SubprocSpec:
         if self.binary_loc is None:
             return
         try:
-            self.cmd = get_script_subproc_command(self.binary_loc, self.cmd[1:])
+            scriptcmd = get_script_subproc_command(self.binary_loc, self.cmd[1:])
+            if scriptcmd is not None:
+                self.cmd = scriptcmd
         except PermissionError:
             e = "xonsh: subprocess mode: permission denied: {0}"
             raise XonshError(e.format(self.cmd[0]))