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
  36 static inline
  37 int lttng_directory_handle_get_dirfd(
  38                 const struct lttng_directory_handle *handle)
  39 {
  40         return handle->dirfd;
  41 }
  42
  43 #else
  44 struct lttng_directory_handle {
  45         char *base_path;
  46 };
  47 #endif
  48
  49 /*
  50  * Initialize a directory handle to the provided path. Passing a NULL path
  51  * returns a handle to the current working directory.
  52  *
  53  * An initialized directory handle must be finalized using
  54  * lttng_directory_handle_fini().
  55  */
  56 LTTNG_HIDDEN
  57 int lttng_directory_handle_init(struct lttng_directory_handle *handle,
  58                 const char *path);
  59
  60 /*
  61  * Initialize a new directory handle to a path relative to an existing handle.
  62  *
  63  * The provided path must already exist. Note that the creation of a
  64  * subdirectory and the creation of a handle are kept as separate operations
  65  * to highlight the fact that there is an inherent race between the creation of
  66  * a directory and the creation of a handle to it.
  67  *
  68  * Passing a NULL path effectively copies the original handle.
  69  *
  70  * An initialized directory handle must be finalized using
  71  * lttng_directory_handle_fini().
  72  */
  73 LTTNG_HIDDEN
  74 int lttng_directory_handle_init_from_handle(
  75                 struct lttng_directory_handle *new_handle,
  76                 const char *path,
  77                 const struct lttng_directory_handle *handle);
  78
  79 /*
  80  * Initialize a new directory handle from an existing directory fd.
  81  *
  82  * The new directory handle assumes the ownership of the directory fd.
  83  * Note that this method should only be used in very specific cases, such as
  84  * re-creating a directory handle from a dirfd passed over a unix socket.
  85  *
  86  * An initialized directory handle must be finalized using
  87  * lttng_directory_handle_fini().
  88  */
  89 LTTNG_HIDDEN
  90 int lttng_directory_handle_init_from_dirfd(
  91                 struct lttng_directory_handle *handle, int dirfd);
  92
  93 /*
  94  * Copy a directory handle.
  95  */
  96 LTTNG_HIDDEN
  97 int lttng_directory_handle_copy(const struct lttng_directory_handle *handle,
  98                 struct lttng_directory_handle *new_copy);
  99
 100 /*
 101  * Move a directory handle. The original directory handle may no longer be
 102  * used after this call. This call cannot fail; directly assign the
 103  * return value to the new directory handle.
 104  *
 105  * It is safe (but unnecessary) to call lttng_directory_handle_fini on the
 106  * original handle.
 107  */
 108 LTTNG_HIDDEN
 109 struct lttng_directory_handle
 110 lttng_directory_handle_move(struct lttng_directory_handle *original);
 111
 112 /*
 113  * Release the resources of a directory handle.
 114  */
 115 LTTNG_HIDDEN
 116 void lttng_directory_handle_fini(struct lttng_directory_handle *handle);
 117
 118 /*
 119  * Create a subdirectory relative to a directory handle.
 120  */
 121 LTTNG_HIDDEN
 122 int lttng_directory_handle_create_subdirectory(
 123                 const struct lttng_directory_handle *handle,
 124                 const char *subdirectory,
 125                 mode_t mode);
 126
 127 /*
 128  * Create a subdirectory relative to a directory handle
 129  * as a given user.
 130  */
 131 LTTNG_HIDDEN
 132 int lttng_directory_handle_create_subdirectory_as_user(
 133                 const struct lttng_directory_handle *handle,
 134                 const char *subdirectory,
 135                 mode_t mode, const struct lttng_credentials *creds);
 136
 137 /*
 138  * Recursively create a directory relative to a directory handle.
 139  */
 140 LTTNG_HIDDEN
 141 int lttng_directory_handle_create_subdirectory_recursive(
 142                 const struct lttng_directory_handle *handle,
 143                 const char *subdirectory_path,
 144                 mode_t mode);
 145
 146 /*
 147  * Recursively create a directory relative to a directory handle
 148  * as a given user.
 149  */
 150 LTTNG_HIDDEN
 151 int lttng_directory_handle_create_subdirectory_recursive_as_user(
 152                 const struct lttng_directory_handle *handle,
 153                 const char *subdirectory_path,
 154                 mode_t mode, const struct lttng_credentials *creds);
 155
 156 #endif /* _COMPAT_PATH_HANDLE_H */