117 lines
2.8 KiB
C
117 lines
2.8 KiB
C
/* @(#)at-base.c 1.1 13/10/27 Copyright 2011-2013 J. Schilling */
|
|
/*
|
|
* Emulate the behavior of openat(fd, name, flag, mode)
|
|
*
|
|
* Note that emulation methods that do not use the /proc filesystem are
|
|
* not MT safe. In the non-MT-safe case, we do:
|
|
*
|
|
* savewd()/fchdir()/open(name)/restorewd()
|
|
*
|
|
* Errors may force us to abort the program as our caller is not expected
|
|
* to know that we do more than a simple open() here and that the
|
|
* working directory may be changed by us.
|
|
*
|
|
* Copyright (c) 2011-13 J. Schilling
|
|
*/
|
|
/*
|
|
* The contents of this file are subject to the terms of the
|
|
* Common Development and Distribution License, Version 1.0 only
|
|
* (the "License"). You may not use this file except in compliance
|
|
* with the License.
|
|
*
|
|
* See the file CDDL.Schily.txt in this distribution for details.
|
|
* A copy of the CDDL is also available via the Internet at
|
|
* http://www.opensource.org/licenses/cddl1.txt
|
|
*
|
|
* When distributing Covered Code, include this CDDL HEADER in each
|
|
* file and include the License file CDDL.Schily.txt from this distribution.
|
|
*/
|
|
|
|
#ifndef ENAMETOOLONG
|
|
#define ENAMETOOLONG EINVAL
|
|
#endif
|
|
|
|
#ifndef _AT_TRIGGER
|
|
#define _AT_TRIGGER 0
|
|
#endif
|
|
|
|
#ifdef PROTOTYPES
|
|
EXPORT FUNC_RESULT
|
|
FUNC_NAME(int fd, const char *name PROTO_DECL)
|
|
#else
|
|
EXPORT FUNC_RESULT
|
|
FUNC_NAME(fd, name KR_ARGS)
|
|
int fd;
|
|
const char *name;
|
|
KR_DECL
|
|
#endif
|
|
{
|
|
int n;
|
|
FUNC_RESULT ret = 0;
|
|
char buf[PATH_MAX];
|
|
char *proc_name;
|
|
struct save_wd save_wd;
|
|
|
|
FLAG_CHECK();
|
|
if (fd == AT_FDCWD || ABS_NAME(name))
|
|
return (FUNC_CALL(name));
|
|
|
|
if ((proc_name = proc_fd2name(buf, fd, name)) != NULL) {
|
|
ret = FUNC_CALL(proc_name);
|
|
if (ret >= 0 || NON_PROCFS_ERRNO(errno))
|
|
return (ret);
|
|
} else if (geterrno() == ENAMETOOLONG) {
|
|
return (-1);
|
|
}
|
|
|
|
if (savewd(&save_wd) < 0) {
|
|
/*
|
|
* We abort here as the caller may not know that we are forced
|
|
* to savewd/fchdir/restorewd here and misinterpret errno.
|
|
*/
|
|
savewd_abort(geterrno());
|
|
/* NOTREACHED */
|
|
return (-1);
|
|
}
|
|
if (fd >= 0 && save_wd.fd == fd) {
|
|
/*
|
|
* If we just opened "fd" with the same number in savewd(), fd
|
|
* must have been illegal when calling openat();
|
|
*/
|
|
closewd(&save_wd);
|
|
seterrno(EBADF);
|
|
return (-1);
|
|
}
|
|
if ((n = fchdir(fd)) < 0) {
|
|
int err = geterrno();
|
|
/*
|
|
* In case that fchdir() is emulated via chdir() and we use a
|
|
* multi hop chdir(), we may be on an undefined intermediate
|
|
* directory. Try to return to last working directory and if
|
|
* this fails, abort for security.
|
|
*/
|
|
if (n == -2 && restorewd(&save_wd) < 0) {
|
|
restorewd_abort(geterrno());
|
|
/* NOTREACHED */
|
|
}
|
|
closewd(&save_wd);
|
|
seterrno(err);
|
|
return (-1);
|
|
}
|
|
|
|
ret = FUNC_CALL(name); /* The actual call() */
|
|
|
|
if (restorewd(&save_wd) < 0) {
|
|
int err = geterrno();
|
|
|
|
closewd(&save_wd);
|
|
restorewd_abort(err);
|
|
/* NOTREACHED */
|
|
seterrno(err);
|
|
return (-1);
|
|
}
|
|
closewd(&save_wd);
|
|
|
|
return (ret);
|
|
}
|