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/* Copyright (C) 1998 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <assert.h>
#include "pty-internal.h"
/* Given a fd on a master pseudoterminal, chown the file associated
with the slave to the calling process, and set its group and
mode appropriately. Note that this is an unprivileged operation. */
/* This "generic Unix" implementation works because we provide the program
/usr/libexec/pt_chown, and it only depends on ptsname() working. */
static const char helper[] = LIBEXECDIR "/pt_chown";
static const char *const argv[] = { "pt_chown", NULL };
int
grantpt (fd)
int fd;
{
struct stat st;
int w, pid;
char namebuf[PTYNAMELEN];
/* Some systems do it for us. */
if (__ptsname_r (fd, namebuf, PTYNAMELEN) == NULL)
return -1;
if (stat (namebuf, &st))
return -1;
if (st.st_uid == getuid ())
return 0;
/* We have to do it in user space. */
pid = fork ();
if (pid == -1)
return -1;
else if (pid == 0)
{
/* Disable core dumps in the child. */
struct rlimit off = { 0, 0 };
setrlimit (RLIMIT_CORE, &off);
/* The helper does its thing on fd PTY_FD. */
if (fd != PTY_FD)
if (dup2 (fd, PTY_FD) == -1)
_exit (FAIL_EBADF);
execve (helper, (char *const *) argv, 0);
_exit (FAIL_EXEC);
}
else
{
if (waitpid (pid, &w, 0) == -1)
return -1;
if (!WIFEXITED (w))
{
__set_errno (ENOEXEC);
return -1;
}
else
switch (WEXITSTATUS(w))
{
case 0:
break;
case FAIL_EBADF:
__set_errno (EBADF);
return -1;
case FAIL_EINVAL:
__set_errno (EINVAL);
return -1;
case FAIL_EACCES:
__set_errno (EACCES);
return -1;
case FAIL_EXEC:
__set_errno (ENOEXEC);
return -1;
default:
assert(! "getpt: internal error: invalid exit code from pt_chown");
}
}
/* Success. */
return 0;
}
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