src/common/compat/directory-handle.hpp

   1 /*
   2  * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef _COMPAT_DIRECTORY_HANDLE_H
   9 #define _COMPAT_DIRECTORY_HANDLE_H
  10
  11 #include <common/credentials.hpp>
  12 #include <common/macros.hpp>
  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 using lttng_directory_handle_destroy_cb = void (*)(struct lttng_directory_handle *, void *);
  33
  34 struct lttng_directory_handle {
  35         struct urcu_ref ref;
  36         ino_t directory_inode;
  37         int dirfd;
  38         lttng_directory_handle_destroy_cb destroy_cb;
  39         void *destroy_cb_data;
  40 };
  41
  42 static inline
  43 int lttng_directory_handle_get_dirfd(
  44                 const struct lttng_directory_handle *handle)
  45 {
  46         return handle->dirfd;
  47 }
  48
  49 #else
  50 struct lttng_directory_handle {
  51         struct urcu_ref ref;
  52         char *base_path;
  53 };
  54 #endif
  55
  56 /*
  57  * Create a directory handle to the provided path. Passing a NULL path
  58  * returns a handle to the current working directory.
  59  *
  60  * The reference to the directory handle must be released using
  61  * lttng_directory_handle_put().
  62  */
  63 struct lttng_directory_handle *lttng_directory_handle_create(
  64                 const char *path);
  65
  66 /*
  67  * Create a new directory handle to a path relative to an existing handle.
  68  *
  69  * The provided path must already exist. Note that the creation of a
  70  * subdirectory and the creation of a handle are kept as separate operations
  71  * to highlight the fact that there is an inherent race between the creation of
  72  * a directory and the creation of a handle to it.
  73  *
  74  * Passing a NULL path effectively copies the original handle.
  75  *
  76  * The reference to the directory handle must be released using
  77  * lttng_directory_handle_put().
  78  */
  79 struct lttng_directory_handle *lttng_directory_handle_create_from_handle(
  80                 const char *path,
  81                 const struct lttng_directory_handle *ref_handle);
  82
  83 /*
  84  * Create a new directory handle from an existing directory fd.
  85  *
  86  * The new directory handle assumes the ownership of the directory fd.
  87  * Note that this method should only be used in very specific cases, such as
  88  * re-creating a directory handle from a dirfd passed over a unix socket.
  89  *
  90  * The reference to the directory handle must be released using
  91  * lttng_directory_handle_put().
  92  */
  93 struct lttng_directory_handle *lttng_directory_handle_create_from_dirfd(
  94                 int dirfd);
  95
  96 /*
  97  * Copy a directory handle.
  98  *
  99  * The reference to the directory handle must be released using
 100  * lttng_directory_handle_put().
 101  */
 102 struct lttng_directory_handle *lttng_directory_handle_copy(
 103                 const struct lttng_directory_handle *handle);
 104
 105 /*
 106  * Acquire a reference to a directory handle.
 107  */
 108 bool lttng_directory_handle_get(struct lttng_directory_handle *handle);
 109
 110 /*
 111  * Release a reference to a directory handle.
 112  */
 113 void lttng_directory_handle_put(struct lttng_directory_handle *handle);
 114
 115 /*
 116  * Create a subdirectory relative to a directory handle.
 117  */
 118 int lttng_directory_handle_create_subdirectory(
 119                 const struct lttng_directory_handle *handle,
 120                 const char *subdirectory,
 121                 mode_t mode);
 122
 123 /*
 124  * Create a subdirectory relative to a directory handle
 125  * as a given user.
 126  */
 127 int lttng_directory_handle_create_subdirectory_as_user(
 128                 const struct lttng_directory_handle *handle,
 129                 const char *subdirectory,
 130                 mode_t mode, const struct lttng_credentials *creds);
 131
 132 /*
 133  * Recursively create a directory relative to a directory handle.
 134  */
 135 int lttng_directory_handle_create_subdirectory_recursive(
 136                 const struct lttng_directory_handle *handle,
 137                 const char *subdirectory_path,
 138                 mode_t mode);
 139
 140 /*
 141  * Recursively create a directory relative to a directory handle
 142  * as a given user.
 143  */
 144 int lttng_directory_handle_create_subdirectory_recursive_as_user(
 145                 const struct lttng_directory_handle *handle,
 146                 const char *subdirectory_path,
 147                 mode_t mode, const struct lttng_credentials *creds);
 148
 149 /*
 150  * Open a file descriptor to a path relative to a directory handle.
 151  */
 152 int lttng_directory_handle_open_file(
 153                 const struct lttng_directory_handle *handle,
 154                 const char *filename,
 155                 int flags, mode_t mode);
 156
 157 /*
 158  * Open a file descriptor to a path relative to a directory handle
 159  * as a given user.
 160  */
 161 int lttng_directory_handle_open_file_as_user(
 162                 const struct lttng_directory_handle *handle,
 163                 const char *filename,
 164                 int flags, mode_t mode,
 165                 const struct lttng_credentials *creds);
 166
 167 /*
 168  * Unlink a file to a path relative to a directory handle.
 169  */
 170 int lttng_directory_handle_unlink_file(
 171                 const struct lttng_directory_handle *handle,
 172                 const char *filename);
 173
 174 /*
 175  * Unlink a file to a path relative to a directory handle as a given user.
 176  */
 177 int lttng_directory_handle_unlink_file_as_user(
 178                 const struct lttng_directory_handle *handle,
 179                 const char *filename,
 180                 const struct lttng_credentials *creds);
 181
 182 /*
 183  * Rename a file from a path relative to a directory handle to a new
 184  * name relative to another directory handle.
 185  */
 186 int lttng_directory_handle_rename(
 187                 const struct lttng_directory_handle *old_handle,
 188                 const char *old_name,
 189                 const struct lttng_directory_handle *new_handle,
 190                 const char *new_name);
 191
 192 /*
 193  * Rename a file from a path relative to a directory handle to a new
 194  * name relative to another directory handle as a given user.
 195  */
 196 int lttng_directory_handle_rename_as_user(
 197                 const struct lttng_directory_handle *old_handle,
 198                 const char *old_name,
 199                 const struct lttng_directory_handle *new_handle,
 200                 const char *new_name,
 201                 const struct lttng_credentials *creds);
 202
 203 /*
 204  * Remove a subdirectory relative to a directory handle.
 205  */
 206 int lttng_directory_handle_remove_subdirectory(
 207                 const struct lttng_directory_handle *handle,
 208                 const char *name);
 209
 210 /*
 211  * Remove a subdirectory relative to a directory handle as a given user.
 212  */
 213 int lttng_directory_handle_remove_subdirectory_as_user(
 214                 const struct lttng_directory_handle *handle,
 215                 const char *name,
 216                 const struct lttng_credentials *creds);
 217
 218 /*
 219  * Remove a subdirectory and remove its contents if it only
 220  * consists in empty directories.
 221  * @flags: enum lttng_directory_handle_rmdir_recursive_flags
 222  */
 223 int lttng_directory_handle_remove_subdirectory_recursive(
 224                 const struct lttng_directory_handle *handle,
 225                 const char *name, int flags);
 226
 227 /*
 228  * Remove a subdirectory and remove its contents if it only
 229  * consists in empty directories as a given user.
 230  * @flags: enum lttng_directory_handle_rmdir_recursive_flags
 231  */
 232 int lttng_directory_handle_remove_subdirectory_recursive_as_user(
 233                 const struct lttng_directory_handle *handle,
 234                 const char *name,
 235                 const struct lttng_credentials *creds,
 236                 int flags);
 237
 238 /*
 239  * stat() a file relative to a directory handle.
 240  */
 241 int lttng_directory_handle_stat(
 242                 const struct lttng_directory_handle *handle,
 243                 const char *name,
 244                 struct stat *stat_buf);
 245
 246 /*
 247  * Returns true if this directory handle is backed by a file
 248  * descriptor, false otherwise.
 249  */
 250 bool lttng_directory_handle_uses_fd(
 251                 const struct lttng_directory_handle *handle);
 252
 253 /*
 254  * Compare two directory handles.
 255  *
 256  * Returns true if the two directory handles are equal, false otherwise.
 257  */
 258 bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
 259                 const struct lttng_directory_handle *rhs);
 260
 261
 262 #endif /* _COMPAT_PATH_HANDLE_H */