1 files changed, 94 insertions, 0 deletions

diff --git a/exec/exec1.c b/exec/exec1.c
new file mode 100644
index 00000000000..d77ca8adf54
--- /dev/null
+++ b/exec/exec1.c
@@ -0,0 +1,94 @@
+/* Program execution for Emacs.
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/wait.h>
+
+#include "exec.h"
+
+/* exec1 is a program which takes another program and its arguments,
+   forks, and executes that program, all while tracing it and its
+   children to use the program execution mechanism defined in exec.c.
+
+   This is necessary to bypass security restrictions which prohibit
+   Emacs from loading executables from certain directories, by, in
+   effect, replacing the executable loader in the Linux kernel.  */
+
+
+
+int
+main (int argc, char **argv)
+{
+  pid_t pid, pid1;
+  extern char **environ;
+  int wstatus;
+
+  pid1 = getpid ();
+  pid = fork ();
+
+  if (!pid)
+    {
+      /* Set the process group used to the parent.  */
+      if (setpgid (0, pid1))
+        perror ("setpgid");
+
+      tracing_execve (argv[2], argv + 2, environ);
+
+      /* An error occured.  Exit with failure.  */
+      exit (127);
+    }
+  else
+    {
+      /* Provide the file name of the loader.  */
+      exec_init (argv[1]);
+
+      if (after_fork (pid))
+        exit (127);
+
+      /* Start waiting for the process to exit.  */
+
+      while (true)
+        {
+          pid1 = exec_waitpid (-1, &wstatus, 0);
+
+          /* If the child process exits normally, exit with its status
+             code.  If not, raise the signal that caused it to
+             exit.  */
+
+          if (pid == pid1)
+            {
+              if (WIFEXITED (wstatus))
+                exit (WEXITSTATUS (wstatus));
+              else /* if WIFSIGNALED (wstatus) */
+                {
+                  raise (WTERMSIG (wstatus));
+
+                  /* Just in case the signal raised doesn't cause an
+                     exit.  */
+                  exit (127);
+                }
+            }
+
+          /* Otherwise, continue looping.  */
+        }
+    }
+}