src/futils.h

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7 #ifndef INCLUDE_futils_h__
   8 #define INCLUDE_futils_h__
   9
  10 #include "common.h"
  11
  12 #include "map.h"
  13 #include "posix.h"
  14 #include "path.h"
  15 #include "pool.h"
  16 #include "strmap.h"
  17 #include "oid.h"
  18
  19 /**
  20  * Filebuffer methods
  21  *
  22  * Read whole files into an in-memory buffer for processing
  23  */
  24 extern int git_futils_readbuffer(git_buf *obj, const char *path);
  25 extern int git_futils_readbuffer_updated(
  26         git_buf *obj, const char *path, git_oid *checksum, int *updated);
  27 extern int git_futils_readbuffer_fd(git_buf *obj, git_file fd, size_t len);
  28
  29 /* Additional constants for `git_futils_writebuffer`'s `open_flags`.  We
  30  * support these internally and they will be removed before the `open` call.
  31  */
  32 #ifndef O_FSYNC
  33 # define O_FSYNC (1 << 31)
  34 #endif
  35
  36 extern int git_futils_writebuffer(
  37         const git_buf *buf, const char *path, int open_flags, mode_t mode);
  38
  39 /**
  40  * File utils
  41  *
  42  * These are custom filesystem-related helper methods. They are
  43  * rather high level, and wrap the underlying POSIX methods
  44  *
  45  * All these methods return 0 on success,
  46  * or an error code on failure and an error message is set.
  47  */
  48
  49 /**
  50  * Create and open a file, while also
  51  * creating all the folders in its path
  52  */
  53 extern int git_futils_creat_withpath(const char *path, const mode_t dirmode, const mode_t mode);
  54
  55 /**
  56  * Create and open a process-locked file
  57  */
  58 extern int git_futils_creat_locked(const char *path, const mode_t mode);
  59
  60 /**
  61  * Create and open a process-locked file, while
  62  * also creating all the folders in its path
  63  */
  64 extern int git_futils_creat_locked_withpath(const char *path, const mode_t dirmode, const mode_t mode);
  65
  66 /**
  67  * Create a path recursively.
  68  */
  69 extern int git_futils_mkdir_r(const char *path, const mode_t mode);
  70
  71 /**
  72  * Flags to pass to `git_futils_mkdir`.
  73  *
  74  * * GIT_MKDIR_EXCL is "exclusive" - i.e. generate an error if dir exists.
  75  * * GIT_MKDIR_PATH says to make all components in the path.
  76  * * GIT_MKDIR_CHMOD says to chmod the final directory entry after creation
  77  * * GIT_MKDIR_CHMOD_PATH says to chmod each directory component in the path
  78  * * GIT_MKDIR_SKIP_LAST says to leave off the last element of the path
  79  * * GIT_MKDIR_SKIP_LAST2 says to leave off the last 2 elements of the path
  80  * * GIT_MKDIR_VERIFY_DIR says confirm final item is a dir, not just EEXIST
  81  * * GIT_MKDIR_REMOVE_FILES says to remove files and recreate dirs
  82  * * GIT_MKDIR_REMOVE_SYMLINKS says to remove symlinks and recreate dirs
  83  *
  84  * Note that the chmod options will be executed even if the directory already
  85  * exists, unless GIT_MKDIR_EXCL is given.
  86  */
  87 typedef enum {
  88         GIT_MKDIR_EXCL = 1,
  89         GIT_MKDIR_PATH = 2,
  90         GIT_MKDIR_CHMOD = 4,
  91         GIT_MKDIR_CHMOD_PATH = 8,
  92         GIT_MKDIR_SKIP_LAST = 16,
  93         GIT_MKDIR_SKIP_LAST2 = 32,
  94         GIT_MKDIR_VERIFY_DIR = 64,
  95         GIT_MKDIR_REMOVE_FILES = 128,
  96         GIT_MKDIR_REMOVE_SYMLINKS = 256,
  97 } git_futils_mkdir_flags;
  98
  99 struct git_futils_mkdir_perfdata
 100 {
 101         size_t stat_calls;
 102         size_t mkdir_calls;
 103         size_t chmod_calls;
 104 };
 105
 106 struct git_futils_mkdir_options
 107 {
 108         git_strmap *dir_map;
 109         git_pool *pool;
 110         struct git_futils_mkdir_perfdata perfdata;
 111 };
 112
 113 /**
 114  * Create a directory or entire path.
 115  *
 116  * This makes a directory (and the entire path leading up to it if requested),
 117  * and optionally chmods the directory immediately after (or each part of the
 118  * path if requested).
 119  *
 120  * @param path The path to create, relative to base.
 121  * @param base Root for relative path.  These directories will never be made.
 122  * @param mode The mode to use for created directories.
 123  * @param flags Combination of the mkdir flags above.
 124  * @param opts Extended options, or null.
 125  * @return 0 on success, else error code
 126  */
 127 extern int git_futils_mkdir_relative(const char *path, const char *base, mode_t mode, uint32_t flags, struct git_futils_mkdir_options *opts);
 128
 129 /**
 130  * Create a directory or entire path.  Similar to `git_futils_mkdir_relative`
 131  * without performance data.
 132  */
 133 extern int git_futils_mkdir(const char *path, mode_t mode, uint32_t flags);
 134
 135 /**
 136  * Create all the folders required to contain
 137  * the full path of a file
 138  */
 139 extern int git_futils_mkpath2file(const char *path, const mode_t mode);
 140
 141 /**
 142  * Flags to pass to `git_futils_rmdir_r`.
 143  *
 144  * * GIT_RMDIR_EMPTY_HIERARCHY - the default; remove hierarchy of empty
 145  *       dirs and generate error if any files are found.
 146  * * GIT_RMDIR_REMOVE_FILES    - attempt to remove files in the hierarchy.
 147  * * GIT_RMDIR_SKIP_NONEMPTY   - skip non-empty directories with no error.
 148  * * GIT_RMDIR_EMPTY_PARENTS   - remove containing directories up to base
 149  *       if removing this item leaves them empty
 150  * * GIT_RMDIR_REMOVE_BLOCKERS - remove blocking file that causes ENOTDIR
 151  * * GIT_RMDIR_SKIP_ROOT       - don't remove root directory itself
 152  */
 153 typedef enum {
 154         GIT_RMDIR_EMPTY_HIERARCHY = 0,
 155         GIT_RMDIR_REMOVE_FILES    = (1 << 0),
 156         GIT_RMDIR_SKIP_NONEMPTY   = (1 << 1),
 157         GIT_RMDIR_EMPTY_PARENTS   = (1 << 2),
 158         GIT_RMDIR_REMOVE_BLOCKERS = (1 << 3),
 159         GIT_RMDIR_SKIP_ROOT       = (1 << 4),
 160 } git_futils_rmdir_flags;
 161
 162 /**
 163  * Remove path and any files and directories beneath it.
 164  *
 165  * @param path Path to the top level directory to process.
 166  * @param base Root for relative path.
 167  * @param flags Combination of git_futils_rmdir_flags values
 168  * @return 0 on success; -1 on error.
 169  */
 170 extern int git_futils_rmdir_r(const char *path, const char *base, uint32_t flags);
 171
 172 /**
 173  * Create and open a temporary file with a `_git2_` suffix.
 174  * Writes the filename into path_out.
 175  * @return On success, an open file descriptor, else an error code < 0.
 176  */
 177 extern int git_futils_mktmp(git_buf *path_out, const char *filename, mode_t mode);
 178
 179 /**
 180  * Move a file on the filesystem, create the
 181  * destination path if it doesn't exist
 182  */
 183 extern int git_futils_mv_withpath(const char *from, const char *to, const mode_t dirmode);
 184
 185 /**
 186  * Copy a file
 187  *
 188  * The filemode will be used for the newly created file.
 189  */
 190 extern int git_futils_cp(
 191         const char *from,
 192         const char *to,
 193         mode_t filemode);
 194
 195 /**
 196  * Set the files atime and mtime to the given time, or the current time
 197  * if `ts` is NULL.
 198  */
 199 extern int git_futils_touch(const char *path, time_t *when);
 200
 201 /**
 202  * Flags that can be passed to `git_futils_cp_r`.
 203  *
 204  * - GIT_CPDIR_CREATE_EMPTY_DIRS: create directories even if there are no
 205  *   files under them (otherwise directories will only be created lazily
 206  *   when a file inside them is copied).
 207  * - GIT_CPDIR_COPY_SYMLINKS: copy symlinks, otherwise they are ignored.
 208  * - GIT_CPDIR_COPY_DOTFILES: copy files with leading '.', otherwise ignored.
 209  * - GIT_CPDIR_OVERWRITE: overwrite pre-existing files with source content,
 210  *   otherwise they are silently skipped.
 211  * - GIT_CPDIR_CHMOD_DIRS: explicitly chmod directories to `dirmode`
 212  * - GIT_CPDIR_SIMPLE_TO_MODE: default tries to replicate the mode of the
 213  *   source file to the target; with this flag, always use 0666 (or 0777 if
 214  *   source has exec bits set) for target.
 215  * - GIT_CPDIR_LINK_FILES will try to use hardlinks for the files
 216  */
 217 typedef enum {
 218         GIT_CPDIR_CREATE_EMPTY_DIRS = (1u << 0),
 219         GIT_CPDIR_COPY_SYMLINKS     = (1u << 1),
 220         GIT_CPDIR_COPY_DOTFILES     = (1u << 2),
 221         GIT_CPDIR_OVERWRITE         = (1u << 3),
 222         GIT_CPDIR_CHMOD_DIRS        = (1u << 4),
 223         GIT_CPDIR_SIMPLE_TO_MODE    = (1u << 5),
 224         GIT_CPDIR_LINK_FILES        = (1u << 6),
 225 } git_futils_cpdir_flags;
 226
 227 /**
 228  * Copy a directory tree.
 229  *
 230  * This copies directories and files from one root to another.  You can
 231  * pass a combinationof GIT_CPDIR flags as defined above.
 232  *
 233  * If you pass the CHMOD flag, then the dirmode will be applied to all
 234  * directories that are created during the copy, overiding the natural
 235  * permissions.  If you do not pass the CHMOD flag, then the dirmode
 236  * will actually be copied from the source files and the `dirmode` arg
 237  * will be ignored.
 238  */
 239 extern int git_futils_cp_r(
 240         const char *from,
 241         const char *to,
 242         uint32_t flags,
 243         mode_t dirmode);
 244
 245 /**
 246  * Open a file readonly and set error if needed.
 247  */
 248 extern int git_futils_open_ro(const char *path);
 249
 250 /**
 251  * Truncate a file, creating it if it doesn't exist.
 252  */
 253 extern int git_futils_truncate(const char *path, int mode);
 254
 255 /**
 256  * Get the filesize in bytes of a file
 257  */
 258 extern int git_futils_filesize(uint64_t *out, git_file fd);
 259
 260 #define GIT_PERMS_IS_EXEC(MODE)         (((MODE) & 0111) != 0)
 261 #define GIT_PERMS_CANONICAL(MODE)       (GIT_PERMS_IS_EXEC(MODE) ? 0755 : 0644)
 262 #define GIT_PERMS_FOR_WRITE(MODE)   (GIT_PERMS_IS_EXEC(MODE) ? 0777 : 0666)
 263
 264 #define GIT_MODE_PERMS_MASK                     0777
 265 #define GIT_MODE_TYPE_MASK                      0170000
 266 #define GIT_MODE_TYPE(MODE)                     ((MODE) & GIT_MODE_TYPE_MASK)
 267 #define GIT_MODE_ISBLOB(MODE)           (GIT_MODE_TYPE(MODE) == GIT_MODE_TYPE(GIT_FILEMODE_BLOB))
 268
 269 /**
 270  * Convert a mode_t from the OS to a legal git mode_t value.
 271  */
 272 extern mode_t git_futils_canonical_mode(mode_t raw_mode);
 273
 274
 275 /**
 276  * Read-only map all or part of a file into memory.
 277  * When possible this function should favor a virtual memory
 278  * style mapping over some form of malloc()+read(), as the
 279  * data access will be random and is not likely to touch the
 280  * majority of the region requested.
 281  *
 282  * @param out buffer to populate with the mapping information.
 283  * @param fd open descriptor to configure the mapping from.
 284  * @param begin first byte to map, this should be page aligned.
 285  * @param len number of bytes to map.
 286  * @return
 287  * - 0 on success;
 288  * - -1 on error.
 289  */
 290 extern int git_futils_mmap_ro(
 291         git_map *out,
 292         git_file fd,
 293         off64_t begin,
 294         size_t len);
 295
 296 /**
 297  * Read-only map an entire file.
 298  *
 299  * @param out buffer to populate with the mapping information.
 300  * @param path path to file to be opened.
 301  * @return
 302  * - 0 on success;
 303  * - GIT_ENOTFOUND if not found;
 304  * - -1 on an unspecified OS related error.
 305  */
 306 extern int git_futils_mmap_ro_file(
 307         git_map *out,
 308         const char *path);
 309
 310 /**
 311  * Release the memory associated with a previous memory mapping.
 312  * @param map the mapping description previously configured.
 313  */
 314 extern void git_futils_mmap_free(git_map *map);
 315
 316 /**
 317  * Create a "fake" symlink (text file containing the target path).
 318  *
 319  * @param target original symlink target
 320  * @param path symlink file to be created
 321  * @return 0 on success, -1 on error
 322  */
 323 extern int git_futils_fake_symlink(const char *target, const char *path);
 324
 325 /**
 326  * A file stamp represents a snapshot of information about a file that can
 327  * be used to test if the file changes.  This portable implementation is
 328  * based on stat data about that file, but it is possible that OS specific
 329  * versions could be implemented in the future.
 330  */
 331 typedef struct {
 332         struct timespec mtime;
 333         uint64_t size;
 334         unsigned int ino;
 335 } git_futils_filestamp;
 336
 337 /**
 338  * Compare stat information for file with reference info.
 339  *
 340  * This function updates the file stamp to current data for the given path
 341  * and returns 0 if the file is up-to-date relative to the prior setting,
 342  * 1 if the file has been changed, or GIT_ENOTFOUND if the file doesn't
 343  * exist.  This will not call git_error_set, so you must set the error if you
 344  * plan to return an error.
 345  *
 346  * @param stamp File stamp to be checked
 347  * @param path Path to stat and check if changed
 348  * @return 0 if up-to-date, 1 if out-of-date, GIT_ENOTFOUND if cannot stat
 349  */
 350 extern int git_futils_filestamp_check(
 351         git_futils_filestamp *stamp, const char *path);
 352
 353 /**
 354  * Set or reset file stamp data
 355  *
 356  * This writes the target file stamp.  If the source is NULL, this will set
 357  * the target stamp to values that will definitely be out of date.  If the
 358  * source is not NULL, this copies the source values to the target.
 359  *
 360  * @param tgt File stamp to write to
 361  * @param src File stamp to copy from or NULL to clear the target
 362  */
 363 extern void git_futils_filestamp_set(
 364         git_futils_filestamp *tgt, const git_futils_filestamp *src);
 365
 366 /**
 367  * Set file stamp data from stat structure
 368  */
 369 extern void git_futils_filestamp_set_from_stat(
 370         git_futils_filestamp *stamp, struct stat *st);
 371
 372 /**
 373  * `fsync` the parent directory of the given path, if `fsync` is
 374  * supported for directories on this platform.
 375  *
 376  * @param path Path of the directory to sync.
 377  * @return 0 on success, -1 on error
 378  */
 379 extern int git_futils_fsync_dir(const char *path);
 380
 381 /**
 382  * `fsync` the parent directory of the given path, if `fsync` is
 383  * supported for directories on this platform.
 384  *
 385  * @param path Path of the file whose parent directory should be synced.
 386  * @return 0 on success, -1 on error
 387  */
 388 extern int git_futils_fsync_parent(const char *path);
 389
 390 #endif