1 /* Entering namespaces for test case isolation. 2 Copyright (C) 2016-2022 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 #ifndef SUPPORT_NAMESPACE_H 20 #define SUPPORT_NAMESPACE_H 21 22 #include <stdbool.h> 23 #include <sys/cdefs.h> 24 25 __BEGIN_DECLS 26 27 /* Attempts to become root (or acquire root-like privileges), possibly 28 with the help of user namespaces. Return true if (restricted) root 29 privileges could be attained in some way. Print diagnostics to 30 standard output. 31 32 Note that this function generally has to be called before a process 33 becomes multi-threaded, otherwise it may fail with insufficient 34 privileges on systems which would support this operation for 35 single-threaded processes. */ 36 bool support_become_root (void); 37 38 /* Return true if this process can perform a chroot operation. In 39 general, this is only possible if support_become_root has been 40 called. Note that the actual test is performed in a subprocess, 41 after fork, so that the file system root of the original process is 42 not changed. */ 43 bool support_can_chroot (void); 44 45 /* Enter a network namespace (and a UTS namespace if possible) and 46 configure the loopback interface. Return true if a network 47 namespace could be created. Print diagnostics to standard output. 48 If a network namespace could be created, but networking in it could 49 not be configured, terminate the process. It is recommended to 50 call support_become_root before this function so that the process 51 has sufficient privileges. */ 52 bool support_enter_network_namespace (void); 53 54 /* Enter a mount namespace and mark / as private (not shared). If 55 this function returns true, mount operations in this process will 56 not affect the host system afterwards. */ 57 bool support_enter_mount_namespace (void); 58 59 /* Return true if support_enter_network_namespace managed to enter a 60 UTS namespace. */ 61 bool support_in_uts_namespace (void); 62 63 /* Invoke CALLBACK (CLOSURE) in a subprocess created using fork. 64 Terminate the calling process if the subprocess exits with a 65 non-zero exit status. */ 66 void support_isolate_in_subprocess (void (*callback) (void *), void *closure); 67 68 /* Describe the setup of a chroot environment, for 69 support_chroot_create below. */ 70 struct support_chroot_configuration 71 { 72 /* File contents. The files are not created if the field is 73 NULL. */ 74 const char *resolv_conf; /* /etc/resolv.conf. */ 75 const char *hosts; /* /etc/hosts. */ 76 const char *host_conf; /* /etc/host.conf. */ 77 const char *aliases; /* /etc/aliases. */ 78 }; 79 80 /* The result of the creation of a chroot. */ 81 struct support_chroot 82 { 83 /* Path information. All these paths are relative to the parent 84 chroot. */ 85 86 /* Path to the chroot directory. */ 87 char *path_chroot; 88 89 /* Paths to files in the chroot. These are absolute and outside of 90 the chroot. */ 91 char *path_resolv_conf; /* /etc/resolv.conf. */ 92 char *path_hosts; /* /etc/hosts. */ 93 char *path_host_conf; /* /etc/host.conf. */ 94 char *path_aliases; /* /etc/aliases. */ 95 }; 96 97 /* Create a chroot environment. The returned data should be freed 98 using support_chroot_free below. The files will be deleted when 99 the process exits. This function does not enter the chroot. */ 100 struct support_chroot *support_chroot_create 101 (struct support_chroot_configuration); 102 103 /* Deallocate the chroot information created by 104 support_chroot_create. */ 105 void support_chroot_free (struct support_chroot *); 106 107 __END_DECLS 108 109 #endif 110