1 /* Return true if the process can perform a chroot operation. 2 Copyright (C) 2017-2022 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library 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 GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #include <errno.h> 20 #include <stdio.h> 21 #include <support/check.h> 22 #include <support/namespace.h> 23 #include <support/support.h> 24 #include <support/xunistd.h> 25 #include <sys/stat.h> 26 #include <unistd.h> 27 28 static void callback(void * closure)29callback (void *closure) 30 { 31 int *result = closure; 32 struct stat64 before; 33 xstat ("/dev", &before); 34 if (chroot ("/dev") != 0) 35 { 36 *result = errno; 37 return; 38 } 39 struct stat64 after; 40 xstat ("/", &after); 41 TEST_VERIFY (before.st_dev == after.st_dev); 42 TEST_VERIFY (before.st_ino == after.st_ino); 43 *result = 0; 44 } 45 46 bool support_can_chroot(void)47support_can_chroot (void) 48 { 49 int *result = support_shared_allocate (sizeof (*result)); 50 *result = 0; 51 support_isolate_in_subprocess (callback, result); 52 bool ok = *result == 0; 53 if (!ok) 54 { 55 static bool already_warned; 56 if (!already_warned) 57 { 58 already_warned = true; 59 errno = *result; 60 printf ("warning: this process does not support chroot: %m\n"); 61 } 62 } 63 support_shared_free (result); 64 return ok; 65 } 66