1/*********************************************************************** 2* * 3* This software is part of the ast package * 4* Copyright (c) 1985-2011 AT&T Intellectual Property * 5* and is licensed under the * 6* Eclipse Public License, Version 1.0 * 7* by AT&T Intellectual Property * 8* * 9* A copy of the License is available at * 10* http://www.eclipse.org/org/documents/epl-v10.html * 11* (with md5 checksum b35adb5213ca9657e911e9befb180842) * 12* * 13* Information and Software Systems Research * 14* AT&T Research * 15* Florham Park NJ * 16* * 17* Glenn Fowler <gsf@research.att.com> * 18* David Korn <dgk@research.att.com> * 19* Phong Vo <kpv@research.att.com> * 20* * 21***********************************************************************/ 22#pragma prototyped 23/* 24 * AT&T Bell Laboratories 25 * return 1 if dir [any dir] is the preroot 26 */ 27 28#include <ast.h> 29#include <preroot.h> 30 31#if FS_PREROOT 32 33#include <ls.h> 34 35/* 36 * return 1 if files a and b are the same under preroot 37 * 38 * NOTE: the kernel disables preroot for set-uid processes 39 */ 40 41static int 42same(const char* a, const char* b) 43{ 44 int i; 45 int euid; 46 int ruid; 47 48 struct stat ast; 49 struct stat bst; 50 51 if ((ruid = getuid()) != (euid = geteuid())) setuid(ruid); 52 i = !stat(a, &ast) && !stat(b, &bst) && ast.st_dev == bst.st_dev && ast.st_ino == bst.st_ino; 53 if (ruid != euid) setuid(euid); 54 return(i); 55} 56 57int 58ispreroot(const char* dir) 59{ 60 static int prerooted = -1; 61 62 if (dir) return(same("/", dir)); 63 if (prerooted < 0) prerooted = !same("/", PR_REAL); 64 return(prerooted); 65} 66 67#else 68 69NoN(ispreroot) 70 71#endif 72