src/common/compat/directory-handle.h

   1 /*
   2  * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef _COMPAT_DIRECTORY_HANDLE_H
  19 #define _COMPAT_DIRECTORY_HANDLE_H
  20
  21 #include <common/macros.h>
  22 #include <common/credentials.h>
  23
  24 /*
  25  * Some platforms, such as Solaris 10, do not support directory file descriptors
  26  * and their associated functions (*at(...)), which are defined in POSIX.2008.
  27  *
  28  * This wrapper provides a handle that is either a copy of a directory's path
  29  * or a directory file descriptors, depending on the platform's capabilities.
  30  */
  31 #ifdef COMPAT_DIRFD
  32 struct lttng_directory_handle {
  33         int dirfd;
  34 };
  35 #else
  36 struct lttng_directory_handle {
  37         char *base_path;
  38 };
  39 #endif
  40
  41 /*
  42  * Initialize a directory handle to the provided path. Passing a NULL path
  43  * returns a handle to the current working directory.
  44  *
  45  * An initialized directory handle must be finalized using
  46  * lttng_directory_handle_fini().
  47  */
  48 LTTNG_HIDDEN
  49 int lttng_directory_handle_init(struct lttng_directory_handle *handle,
  50                 const char *path);
  51
  52 /*
  53  * Initialize a new directory handle to a path relative to an existing handle.
  54  *
  55  * The provided path must already exist. Note that the creation of a
  56  * subdirectory and the creation of a handle are kept as separate operations
  57  * to highlight the fact that there is an inherent race between the creation of
  58  * a directory and the creation of a handle to it.
  59  *
  60  * Passing a NULL path effectively copies the original handle.
  61  *
  62  * An initialized directory handle must be finalized using
  63  * lttng_directory_handle_fini().
  64  */
  65 LTTNG_HIDDEN
  66 int lttng_directory_handle_init_from_handle(
  67                 struct lttng_directory_handle *new_handle,
  68                 const char *path,
  69                 const struct lttng_directory_handle *handle);
  70
  71 /*
  72  * Initialize a new directory handle from an existing directory fd.
  73  *
  74  * The new directory handle assumes the ownership of the directory fd.
  75  * Note that this method should only be used in very specific cases, such as
  76  * re-creating a directory handle from a dirfd passed over a unix socket.
  77  *
  78  * An initialized directory handle must be finalized using
  79  * lttng_directory_handle_fini().
  80  */
  81 LTTNG_HIDDEN
  82 int lttng_directory_handle_init_from_dirfd(
  83                 struct lttng_directory_handle *handle, int dirfd);
  84
  85 /*
  86  * Copy a directory handle.
  87  */
  88 LTTNG_HIDDEN
  89 int lttng_directory_handle_copy(const struct lttng_directory_handle *handle,
  90                 struct lttng_directory_handle *new_copy);
  91
  92 /*
  93  * Move a directory handle. The original directory handle may no longer be
  94  * used after this call. This call cannot fail; directly assign the
  95  * return value to the new directory handle.
  96  *
  97  * It is safe (but unnecessary) to call lttng_directory_handle_fini on the
  98  * original handle.
  99  */
 100 LTTNG_HIDDEN
 101 struct lttng_directory_handle
 102 lttng_directory_handle_move(struct lttng_directory_handle *original);
 103
 104 /*
 105  * Release the resources of a directory handle.
 106  */
 107 LTTNG_HIDDEN
 108 void lttng_directory_handle_fini(struct lttng_directory_handle *handle);
 109
 110 /*
 111  * Create a subdirectory relative to a directory handle.
 112  */
 113 LTTNG_HIDDEN
 114 int lttng_directory_handle_create_subdirectory(
 115                 const struct lttng_directory_handle *handle,
 116                 const char *subdirectory,
 117                 mode_t mode);
 118
 119 /*
 120  * Create a subdirectory relative to a directory handle
 121  * as a given user.
 122  */
 123 LTTNG_HIDDEN
 124 int lttng_directory_handle_create_subdirectory_as_user(
 125                 const struct lttng_directory_handle *handle,
 126                 const char *subdirectory,
 127                 mode_t mode, const struct lttng_credentials *creds);
 128
 129 /*
 130  * Recursively create a directory relative to a directory handle.
 131  */
 132 LTTNG_HIDDEN
 133 int lttng_directory_handle_create_subdirectory_recursive(
 134                 const struct lttng_directory_handle *handle,
 135                 const char *subdirectory_path,
 136                 mode_t mode);
 137
 138 /*
 139  * Recursively create a directory relative to a directory handle
 140  * as a given user.
 141  */
 142 LTTNG_HIDDEN
 143 int lttng_directory_handle_create_subdirectory_recursive_as_user(
 144                 const struct lttng_directory_handle *handle,
 145                 const char *subdirectory_path,
 146                 mode_t mode, const struct lttng_credentials *creds);
 147
 148 #endif /* _COMPAT_PATH_HANDLE_H */