1 /* unlinkdir.c - determine whether we can unlink directories 2 3 Copyright (C) 2005-2006, 2009-2021 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 17 18 /* Written by Paul Eggert, Jim Meyering, and David Bartley. */ 19 20 #include <config.h> 21 22 #include "unlinkdir.h" 23 #include "priv-set.h" 24 #include "root-uid.h" 25 #include <unistd.h> 26 27 #if ! UNLINK_CANNOT_UNLINK_DIR 28 29 /* Return true if we cannot unlink directories, false if we might be 30 able to unlink directories. */ 31 32 bool 33 cannot_unlink_dir (void) /* */ 34 { 35 static bool initialized; 36 static bool cannot; 37 38 if (! initialized) 39 { 40 # if defined PRIV_SYS_LINKDIR 41 /* We might be able to unlink directories if we cannot 42 determine our privileges, or if we have the 43 PRIV_SYS_LINKDIR privilege. */ 44 cannot = (priv_set_ismember (PRIV_SYS_LINKDIR) == 0); 45 # else 46 /* In traditional Unix, only root can unlink directories. */ 47 cannot = (geteuid () != ROOT_UID); 48 # endif 49 initialized = true; 50 } 51 52 return cannot; 53 } 54 55 #endif