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 struct lttng_directory_handle *lttng_directory_handle_create(
  65                 const char *path);
  66
  67 /*
  68  * Create a new directory handle to a path relative to an existing handle.
  69  *
  70  * The provided path must already exist. Note that the creation of a
  71  * subdirectory and the creation of a handle are kept as separate operations
  72  * to highlight the fact that there is an inherent race between the creation of
  73  * a directory and the creation of a handle to it.
  74  *
  75  * Passing a NULL path effectively copies the original handle.
  76  *
  77  * The reference to the directory handle must be released using
  78  * lttng_directory_handle_put().
  79  */
  80 struct lttng_directory_handle *lttng_directory_handle_create_from_handle(
  81                 const char *path,
  82                 const struct lttng_directory_handle *ref_handle);
  83
  84 /*
  85  * Create a new directory handle from an existing directory fd.
  86  *
  87  * The new directory handle assumes the ownership of the directory fd.
  88  * Note that this method should only be used in very specific cases, such as
  89  * re-creating a directory handle from a dirfd passed over a unix socket.
  90  *
  91  * The reference to the directory handle must be released using
  92  * lttng_directory_handle_put().
  93  */
  94 struct lttng_directory_handle *lttng_directory_handle_create_from_dirfd(
  95                 int dirfd);
  96
  97 /*
  98  * Copy a directory handle.
  99  *
 100  * The reference to the directory handle must be released using
 101  * lttng_directory_handle_put().
 102  */
 103 struct lttng_directory_handle *lttng_directory_handle_copy(
 104                 const struct lttng_directory_handle *handle);
 105
 106 /*
 107  * Acquire a reference to a directory handle.
 108  */
 109 bool lttng_directory_handle_get(struct lttng_directory_handle *handle);
 110
 111 /*
 112  * Release a reference to a directory handle.
 113  */
 114 void lttng_directory_handle_put(struct lttng_directory_handle *handle);
 115
 116 /*
 117  * Create a subdirectory relative to a directory handle.
 118  */
 119 int lttng_directory_handle_create_subdirectory(
 120                 const struct lttng_directory_handle *handle,
 121                 const char *subdirectory,
 122                 mode_t mode);
 123
 124 /*
 125  * Create a subdirectory relative to a directory handle
 126  * as a given user.
 127  */
 128 int lttng_directory_handle_create_subdirectory_as_user(
 129                 const struct lttng_directory_handle *handle,
 130                 const char *subdirectory,
 131                 mode_t mode, const struct lttng_credentials *creds);
 132
 133 /*
 134  * Recursively create a directory relative to a directory handle.
 135  */
 136 int lttng_directory_handle_create_subdirectory_recursive(
 137                 const struct lttng_directory_handle *handle,
 138                 const char *subdirectory_path,
 139                 mode_t mode);
 140
 141 /*
 142  * Recursively create a directory relative to a directory handle
 143  * as a given user.
 144  */
 145 int lttng_directory_handle_create_subdirectory_recursive_as_user(
 146                 const struct lttng_directory_handle *handle,
 147                 const char *subdirectory_path,
 148                 mode_t mode, const struct lttng_credentials *creds);
 149
 150 /*
 151  * Open a file descriptor to a path relative to a directory handle.
 152  */
 153 int lttng_directory_handle_open_file(
 154                 const struct lttng_directory_handle *handle,
 155                 const char *filename,
 156                 int flags, mode_t mode);
 157
 158 /*
 159  * Open a file descriptor to a path relative to a directory handle
 160  * as a given user.
 161  */
 162 int lttng_directory_handle_open_file_as_user(
 163                 const struct lttng_directory_handle *handle,
 164                 const char *filename,
 165                 int flags, mode_t mode,
 166                 const struct lttng_credentials *creds);
 167
 168 /*
 169  * Unlink a file to a path relative to a directory handle.
 170  */
 171 int lttng_directory_handle_unlink_file(
 172                 const struct lttng_directory_handle *handle,
 173                 const char *filename);
 174
 175 /*
 176  * Unlink a file to a path relative to a directory handle as a given user.
 177  */
 178 int lttng_directory_handle_unlink_file_as_user(
 179                 const struct lttng_directory_handle *handle,
 180                 const char *filename,
 181                 const struct lttng_credentials *creds);
 182
 183 /*
 184  * Rename a file from a path relative to a directory handle to a new
 185  * name relative to another directory handle.
 186  */
 187 int lttng_directory_handle_rename(
 188                 const struct lttng_directory_handle *old_handle,
 189                 const char *old_name,
 190                 const struct lttng_directory_handle *new_handle,
 191                 const char *new_name);
 192
 193 /*
 194  * Rename a file from a path relative to a directory handle to a new
 195  * name relative to another directory handle as a given user.
 196  */
 197 int lttng_directory_handle_rename_as_user(
 198                 const struct lttng_directory_handle *old_handle,
 199                 const char *old_name,
 200                 const struct lttng_directory_handle *new_handle,
 201                 const char *new_name,
 202                 const struct lttng_credentials *creds);
 203
 204 /*
 205  * Remove a subdirectory relative to a directory handle.
 206  */
 207 int lttng_directory_handle_remove_subdirectory(
 208                 const struct lttng_directory_handle *handle,
 209                 const char *name);
 210
 211 /*
 212  * Remove a subdirectory relative to a directory handle as a given user.
 213  */
 214 int lttng_directory_handle_remove_subdirectory_as_user(
 215                 const struct lttng_directory_handle *handle,
 216                 const char *name,
 217                 const struct lttng_credentials *creds);
 218
 219 /*
 220  * Remove a subdirectory and remove its contents if it only
 221  * consists in empty directories.
 222  * @flags: enum lttng_directory_handle_rmdir_recursive_flags
 223  */
 224 int lttng_directory_handle_remove_subdirectory_recursive(
 225                 const struct lttng_directory_handle *handle,
 226                 const char *name, int flags);
 227
 228 /*
 229  * Remove a subdirectory and remove its contents if it only
 230  * consists in empty directories as a given user.
 231  * @flags: enum lttng_directory_handle_rmdir_recursive_flags
 232  */
 233 int lttng_directory_handle_remove_subdirectory_recursive_as_user(
 234                 const struct lttng_directory_handle *handle,
 235                 const char *name,
 236                 const struct lttng_credentials *creds,
 237                 int flags);
 238
 239 /*
 240  * stat() a file relative to a directory handle.
 241  */
 242 int lttng_directory_handle_stat(
 243                 const struct lttng_directory_handle *handle,
 244                 const char *name,
 245                 struct stat *stat_buf);
 246
 247 /*
 248  * Returns true if this directory handle is backed by a file
 249  * descriptor, false otherwise.
 250  */
 251 bool lttng_directory_handle_uses_fd(
 252                 const struct lttng_directory_handle *handle);
 253
 254 /*
 255  * Compare two directory handles.
 256  *
 257  * Returns true if the two directory handles are equal, false otherwise.
 258  */
 259 bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
 260                 const struct lttng_directory_handle *rhs);
 261
 262
 263 #endif /* _COMPAT_PATH_HANDLE_H */