1 /* Determine whether we can write any file. 2 3 Copyright (C) 2007, 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. */ 19 20 #include <config.h> 21 22 #include "write-any-file.h" 23 #include "priv-set.h" 24 #include "root-uid.h" 25 26 #include <unistd.h> 27 28 /* Return true if we know that we can write any file, including 29 writing directories. */ 30 31 bool 32 can_write_any_file (void) /* */ 33 { 34 static bool initialized; 35 static bool can_write; 36 37 if (! initialized) 38 { 39 bool can = false; 40 #if defined PRIV_FILE_DAC_WRITE 41 can = (priv_set_ismember (PRIV_FILE_DAC_WRITE) == 1); 42 #else 43 /* In traditional Unix, only root can unlink directories. */ 44 can = (geteuid () == ROOT_UID); 45 #endif 46 can_write = can; 47 initialized = true; 48 } 49 50 return can_write; 51 }