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