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95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
/* Program execution for Emacs.
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Copyright (C) 2023-2024 Free Software Foundation, Inc.
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This file is part of GNU Emacs.
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GNU Emacs is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at
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your option) any later version.
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GNU Emacs is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <sys/wait.h>
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#include "exec.h"
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/* exec1 is a program which takes another program and its arguments,
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forks, and executes that program, all while tracing it and its
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children to use the program execution mechanism defined in exec.c.
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This is necessary to bypass security restrictions which prohibit
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Emacs from loading executables from certain directories, by, in
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effect, replacing the executable loader in the Linux kernel. */
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int
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main (int argc, char **argv)
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{
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pid_t pid, pid1;
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extern char **environ;
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int wstatus;
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pid1 = getpid ();
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pid = fork ();
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if (!pid)
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{
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/* Set the process group used to the parent. */
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if (setpgid (0, pid1))
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perror ("setpgid");
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tracing_execve (argv[2], argv + 2, environ);
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/* An error occurred. Exit with failure. */
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exit (127);
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}
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else
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{
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/* Provide the file name of the loader. */
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exec_init (argv[1]);
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if (after_fork (pid))
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exit (127);
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/* Start waiting for the process to exit. */
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while (true)
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{
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pid1 = exec_waitpid (-1, &wstatus, 0);
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/* If the child process exits normally, exit with its status
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code. If not, raise the signal that caused it to
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exit. */
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if (pid == pid1)
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{
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if (WIFEXITED (wstatus))
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exit (WEXITSTATUS (wstatus));
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else /* if WIFSIGNALED (wstatus) */
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{
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raise (WTERMSIG (wstatus));
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/* Just in case the signal raised doesn't cause an
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exit. */
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exit (127);
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}
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}
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/* Otherwise, continue looping. */
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}
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}
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}
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