src/common/compat/directory-handle.h

   1 /*
   2  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef _COMPAT_DIRECTORY_HANDLE_H
   9 #define _COMPAT_DIRECTORY_HANDLE_H
  10
  11 #include <common/credentials.h>
  12 #include <common/macros.h>
  13 #include <sys/stat.h>
  14 #include <urcu/ref.h>
  15
  16 enum lttng_directory_handle_rmdir_recursive_flags {
  17         LTTNG_DIRECTORY_HANDLE_FAIL_NON_EMPTY_FLAG = (1U << 0),
  18         LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG = (1U << 1),
  19 };
  20
  21 /*
  22  * Some platforms, such as Solaris 10, do not support directory file descriptors
  23  * and their associated functions (*at(...)), which are defined in POSIX.2008.
  24  *
  25  * This wrapper provides a handle that is either a copy of a directory's path
  26  * or a directory file descriptors, depending on the platform's capabilities.
  27  */
  28 #ifdef HAVE_DIRFD
  29
  30 struct lttng_directory_handle;
  31
  32 typedef void (*lttng_directory_handle_destroy_cb)(
  33                 struct lttng_directory_handle *handle, void *data);
  34
  35 struct lttng_directory_handle {
  36         struct urcu_ref ref;
  37         ino_t directory_inode;
  38         int dirfd;
  39         lttng_directory_handle_destroy_cb destroy_cb;
  40         void *destroy_cb_data;
  41 };
  42
  43 static inline
  44 int lttng_directory_handle_get_dirfd(
  45                 const struct lttng_directory_handle *handle)
  46 {
  47         return handle->dirfd;
  48 }
  49
  50 #else
  51 struct lttng_directory_handle {
  52         struct urcu_ref ref;
  53         char *base_path;
  54 };
  55 #endif
  56
  57 /*
  58  * Create a directory handle to the provided path. Passing a NULL path
  59  * returns a handle to the current working directory.
  60  *
  61  * The reference to the directory handle must be released using
  62  * lttng_directory_handle_put().
  63  */
  64 LTTNG_HIDDEN
  65 struct lttng_directory_handle *lttng_directory_handle_create(
  66                 const char *path);
  67
  68 /*
  69  * Create a new directory handle to a path relative to an existing handle.
  70  *
  71  * The provided path must already exist. Note that the creation of a
  72  * subdirectory and the creation of a handle are kept as separate operations
  73  * to highlight the fact that there is an inherent race between the creation of
  74  * a directory and the creation of a handle to it.
  75  *
  76  * Passing a NULL path effectively copies the original handle.
  77  *
  78  * The reference to the directory handle must be released using
  79  * lttng_directory_handle_put().
  80  */
  81 LTTNG_HIDDEN
  82 struct lttng_directory_handle *lttng_directory_handle_create_from_handle(
  83                 const char *path,
  84                 const struct lttng_directory_handle *ref_handle);
  85
  86 /*
  87  * Create a new directory handle from an existing directory fd.
  88  *
  89  * The new directory handle assumes the ownership of the directory fd.
  90  * Note that this method should only be used in very specific cases, such as
  91  * re-creating a directory handle from a dirfd passed over a unix socket.
  92  *
  93  * The reference to the directory handle must be released using
  94  * lttng_directory_handle_put().
  95  */
  96 LTTNG_HIDDEN
  97 struct lttng_directory_handle *lttng_directory_handle_create_from_dirfd(
  98                 int dirfd);
  99
 100 /*
 101  * Copy a directory handle.
 102  *
 103  * The reference to the directory handle must be released using
 104  * lttng_directory_handle_put().
 105  */
 106 LTTNG_HIDDEN
 107 struct lttng_directory_handle *lttng_directory_handle_copy(
 108                 const struct lttng_directory_handle *handle);
 109
 110 /*
 111  * Acquire a reference to a directory handle.
 112  */
 113 LTTNG_HIDDEN
 114 bool lttng_directory_handle_get(struct lttng_directory_handle *handle);
 115
 116 /*
 117  * Release a reference to a directory handle.
 118  */
 119 LTTNG_HIDDEN
 120 void lttng_directory_handle_put(struct lttng_directory_handle *handle);
 121
 122 /*
 123  * Create a subdirectory relative to a directory handle.
 124  */
 125 LTTNG_HIDDEN
 126 int lttng_directory_handle_create_subdirectory(
 127                 const struct lttng_directory_handle *handle,
 128                 const char *subdirectory,
 129                 mode_t mode);
 130
 131 /*
 132  * Create a subdirectory relative to a directory handle
 133  * as a given user.
 134  */
 135 LTTNG_HIDDEN
 136 int lttng_directory_handle_create_subdirectory_as_user(
 137                 const struct lttng_directory_handle *handle,
 138                 const char *subdirectory,
 139                 mode_t mode, const struct lttng_credentials *creds);
 140
 141 /*
 142  * Recursively create a directory relative to a directory handle.
 143  */
 144 LTTNG_HIDDEN
 145 int lttng_directory_handle_create_subdirectory_recursive(
 146                 const struct lttng_directory_handle *handle,
 147                 const char *subdirectory_path,
 148                 mode_t mode);
 149
 150 /*
 151  * Recursively create a directory relative to a directory handle
 152  * as a given user.
 153  */
 154 LTTNG_HIDDEN
 155 int lttng_directory_handle_create_subdirectory_recursive_as_user(
 156                 const struct lttng_directory_handle *handle,
 157                 const char *subdirectory_path,
 158                 mode_t mode, const struct lttng_credentials *creds);
 159
 160 /*
 161  * Open a file descriptor to a path relative to a directory handle.
 162  */
 163 LTTNG_HIDDEN
 164 int lttng_directory_handle_open_file(
 165                 const struct lttng_directory_handle *handle,
 166                 const char *filename,
 167                 int flags, mode_t mode);
 168
 169 /*
 170  * Open a file descriptor to a path relative to a directory handle
 171  * as a given user.
 172  */
 173 LTTNG_HIDDEN
 174 int lttng_directory_handle_open_file_as_user(
 175                 const struct lttng_directory_handle *handle,
 176                 const char *filename,
 177                 int flags, mode_t mode,
 178                 const struct lttng_credentials *creds);
 179
 180 /*
 181  * Unlink a file to a path relative to a directory handle.
 182  */
 183 LTTNG_HIDDEN
 184 int lttng_directory_handle_unlink_file(
 185                 const struct lttng_directory_handle *handle,
 186                 const char *filename);
 187
 188 /*
 189  * Unlink a file to a path relative to a directory handle as a given user.
 190  */
 191 LTTNG_HIDDEN
 192 int lttng_directory_handle_unlink_file_as_user(
 193                 const struct lttng_directory_handle *handle,
 194                 const char *filename,
 195                 const struct lttng_credentials *creds);
 196
 197 /*
 198  * Rename a file from a path relative to a directory handle to a new
 199  * name relative to another directory handle.
 200  */
 201 LTTNG_HIDDEN
 202 int lttng_directory_handle_rename(
 203                 const struct lttng_directory_handle *old_handle,
 204                 const char *old_name,
 205                 const struct lttng_directory_handle *new_handle,
 206                 const char *new_name);
 207
 208 /*
 209  * Rename a file from a path relative to a directory handle to a new
 210  * name relative to another directory handle as a given user.
 211  */
 212 LTTNG_HIDDEN
 213 int lttng_directory_handle_rename_as_user(
 214                 const struct lttng_directory_handle *old_handle,
 215                 const char *old_name,
 216                 const struct lttng_directory_handle *new_handle,
 217                 const char *new_name,
 218                 const struct lttng_credentials *creds);
 219
 220 /*
 221  * Remove a subdirectory relative to a directory handle.
 222  */
 223 LTTNG_HIDDEN
 224 int lttng_directory_handle_remove_subdirectory(
 225                 const struct lttng_directory_handle *handle,
 226                 const char *name);
 227
 228 /*
 229  * Remove a subdirectory relative to a directory handle as a given user.
 230  */
 231 LTTNG_HIDDEN
 232 int lttng_directory_handle_remove_subdirectory_as_user(
 233                 const struct lttng_directory_handle *handle,
 234                 const char *name,
 235                 const struct lttng_credentials *creds);
 236
 237 /*
 238  * Remove a subdirectory and remove its contents if it only
 239  * consists in empty directories.
 240  * @flags: enum lttng_directory_handle_rmdir_recursive_flags
 241  */
 242 LTTNG_HIDDEN
 243 int lttng_directory_handle_remove_subdirectory_recursive(
 244                 const struct lttng_directory_handle *handle,
 245                 const char *name, int flags);
 246
 247 /*
 248  * Remove a subdirectory and remove its contents if it only
 249  * consists in empty directories as a given user.
 250  * @flags: enum lttng_directory_handle_rmdir_recursive_flags
 251  */
 252 LTTNG_HIDDEN
 253 int lttng_directory_handle_remove_subdirectory_recursive_as_user(
 254                 const struct lttng_directory_handle *handle,
 255                 const char *name,
 256                 const struct lttng_credentials *creds,
 257                 int flags);
 258
 259 /*
 260  * stat() a file relative to a directory handle.
 261  */
 262 LTTNG_HIDDEN
 263 int lttng_directory_handle_stat(
 264                 const struct lttng_directory_handle *handle,
 265                 const char *name,
 266                 struct stat *stat_buf);
 267
 268 /*
 269  * Returns true if this directory handle is backed by a file
 270  * descriptor, false otherwise.
 271  */
 272 LTTNG_HIDDEN
 273 bool lttng_directory_handle_uses_fd(
 274                 const struct lttng_directory_handle *handle);
 275
 276 /*
 277  * Compare two directory handles.
 278  *
 279  * Returns true if the two directory handles are equal, false otherwise.
 280  */
 281 LTTNG_HIDDEN
 282 bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
 283                 const struct lttng_directory_handle *rhs);
 284
 285 #endif /* _COMPAT_PATH_HANDLE_H */