2 * unix_apply.c - Code to apply files from a WIM image on UNIX.
6 * Copyright (C) 2012-2016 Eric Biggers
8 * This file is free software; you can redistribute it and/or modify it under
9 * the terms of the GNU Lesser General Public License as published by the Free
10 * Software Foundation; either version 3 of the License, or (at your option) any
13 * This file is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this file; if not, see http://www.gnu.org/licenses/.
31 #include <sys/types.h>
34 #include "wimlib/apply.h"
35 #include "wimlib/assert.h"
36 #include "wimlib/blob_table.h"
37 #include "wimlib/dentry.h"
38 #include "wimlib/error.h"
39 #include "wimlib/file_io.h"
40 #include "wimlib/reparse.h"
41 #include "wimlib/timestamp.h"
42 #include "wimlib/unix_data.h"
44 /* We don't require O_NOFOLLOW, but the advantage of having it is that if we
45 * need to extract a file to a location at which there exists a symbolic link,
46 * open(..., O_NOFOLLOW | ...) recognizes the symbolic link rather than
47 * following it and creating the file somewhere else. (Equivalent to
48 * FILE_OPEN_REPARSE_POINT on Windows.) */
54 unix_get_supported_features(const char *target,
55 struct wim_features *supported_features)
57 supported_features->sparse_files = 1;
58 supported_features->hard_links = 1;
59 supported_features->symlink_reparse_points = 1;
60 supported_features->unix_data = 1;
61 supported_features->timestamps = 1;
62 supported_features->case_sensitive_filenames = 1;
66 #define NUM_PATHBUFS 2 /* We need 2 when creating hard links */
68 struct unix_apply_ctx {
69 /* Extract flags, the pointer to the WIMStruct, etc. */
70 struct apply_ctx common;
72 /* Buffers for building extraction paths (allocated). */
73 char *pathbufs[NUM_PATHBUFS];
75 /* Index of next pathbuf to use */
76 unsigned which_pathbuf;
78 /* Currently open file descriptors for extraction */
79 struct filedes open_fds[MAX_OPEN_FILES];
81 /* Number of currently open file descriptors in open_fds, starting from
82 * the beginning of the array. */
83 unsigned num_open_fds;
85 /* For each currently open file, whether we're writing to it in "sparse"
87 bool is_sparse_file[MAX_OPEN_FILES];
89 /* Whether is_sparse_file[] is true for any currently open file */
90 bool any_sparse_files;
92 /* Buffer for reading reparse point data into memory */
93 u8 reparse_data[REPARSE_DATA_MAX_SIZE];
95 /* Pointer to the next byte in @reparse_data to fill */
98 /* Absolute path to the target directory (allocated buffer). Only set
99 * if needed for absolute symbolic link fixups. */
100 char *target_abspath;
102 /* Number of characters in target_abspath. */
103 size_t target_abspath_nchars;
105 /* Number of special files we couldn't create due to EPERM */
106 unsigned long num_special_files_ignored;
109 /* Returns the number of characters needed to represent the path to the
110 * specified @dentry when extracted, not including the null terminator or the
111 * path to the target directory itself. */
113 unix_dentry_path_length(const struct wim_dentry *dentry)
116 const struct wim_dentry *d;
120 len += d->d_extraction_name_nchars + 1;
122 } while (!dentry_is_root(d) && will_extract_dentry(d));
127 /* Returns the maximum number of characters needed to represent the path to any
128 * dentry in @dentry_list when extracted, including the null terminator and the
129 * path to the target directory itself. */
131 unix_compute_path_max(const struct list_head *dentry_list,
132 const struct unix_apply_ctx *ctx)
136 const struct wim_dentry *dentry;
138 list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
139 len = unix_dentry_path_length(dentry);
144 /* Account for target and null terminator. */
145 return ctx->common.target_nchars + max + 1;
148 /* Builds and returns the filesystem path to which to extract @dentry.
149 * This cycles through NUM_PATHBUFS different buffers. */
151 unix_build_extraction_path(const struct wim_dentry *dentry,
152 struct unix_apply_ctx *ctx)
156 const struct wim_dentry *d;
158 pathbuf = ctx->pathbufs[ctx->which_pathbuf];
159 ctx->which_pathbuf = (ctx->which_pathbuf + 1) % NUM_PATHBUFS;
161 p = &pathbuf[ctx->common.target_nchars +
162 unix_dentry_path_length(dentry)];
166 p -= d->d_extraction_name_nchars;
167 if (d->d_extraction_name_nchars)
168 memcpy(p, d->d_extraction_name,
169 d->d_extraction_name_nchars);
172 } while (!dentry_is_root(d) && will_extract_dentry(d));
177 /* This causes the next call to unix_build_extraction_path() to use the same
178 * path buffer as the previous call. */
180 unix_reuse_pathbuf(struct unix_apply_ctx *ctx)
182 ctx->which_pathbuf = (ctx->which_pathbuf - 1) % NUM_PATHBUFS;
185 /* Builds and returns the filesystem path to which to extract an unspecified
186 * alias of the @inode. This cycles through NUM_PATHBUFS different buffers. */
188 unix_build_inode_extraction_path(const struct wim_inode *inode,
189 struct unix_apply_ctx *ctx)
191 return unix_build_extraction_path(inode_first_extraction_dentry(inode), ctx);
194 /* Should the specified file be extracted as a directory on UNIX? We extract
195 * the file as a directory if FILE_ATTRIBUTE_DIRECTORY is set and the file does
196 * not have a symlink or junction reparse point. It *may* have a different type
197 * of reparse point. */
199 should_extract_as_directory(const struct wim_inode *inode)
201 return (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY) &&
202 !inode_is_symlink(inode);
205 /* Sets the timestamps on a file being extracted. */
207 unix_set_timestamps(const char *path, u64 atime, u64 mtime)
209 #ifdef HAVE_UTIMENSAT
211 struct timespec times[2];
213 times[0] = wim_timestamp_to_timespec(atime);
214 times[1] = wim_timestamp_to_timespec(mtime);
216 if (utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW) == 0)
223 struct timeval times[2];
225 times[0] = wim_timestamp_to_timeval(atime);
226 times[1] = wim_timestamp_to_timeval(mtime);
228 return lutimes(path, times);
232 /* Set metadata on an extracted file. */
234 unix_set_metadata(const struct wim_inode *inode, struct unix_apply_ctx *ctx)
236 const char *path = unix_build_inode_extraction_path(inode, ctx);
237 struct wimlib_unix_data unix_data;
239 if ((ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_UNIX_DATA)
240 && inode_get_unix_data(inode, &unix_data))
242 u32 uid = unix_data.uid;
243 u32 gid = unix_data.gid;
244 u32 mode = unix_data.mode;
246 if (lchown(path, uid, gid) != 0) {
247 if (ctx->common.extract_flags &
248 WIMLIB_EXTRACT_FLAG_STRICT_ACLS)
250 ERROR_WITH_ERRNO("Can't set uid=%"PRIu32" and "
251 "gid=%"PRIu32" on \"%s\"",
253 return WIMLIB_ERR_SET_SECURITY;
255 WARNING_WITH_ERRNO("Can't set uid=%"PRIu32" and "
256 "gid=%"PRIu32" on \"%s\"",
260 if (!inode_is_symlink(inode) && chmod(path, mode) != 0) {
261 if (ctx->common.extract_flags &
262 WIMLIB_EXTRACT_FLAG_STRICT_ACLS)
264 ERROR_WITH_ERRNO("Can't set mode=0%"PRIo32" "
265 "on \"%s\"", mode, path);
266 return WIMLIB_ERR_SET_SECURITY;
268 WARNING_WITH_ERRNO("Can't set mode=0%"PRIo32" "
269 "on \"%s\"", mode, path);
273 if (unix_set_timestamps(path, inode->i_last_access_time,
274 inode->i_last_write_time) != 0)
276 if (ctx->common.extract_flags &
277 WIMLIB_EXTRACT_FLAG_STRICT_TIMESTAMPS)
279 ERROR_WITH_ERRNO("Can't set timestamps on \"%s\"", path);
280 return WIMLIB_ERR_SET_TIMESTAMPS;
282 WARNING_WITH_ERRNO("Can't set timestamps on \"%s\"", path);
288 * Extract all needed aliases of the specified @inode, where the first alias has
289 * already been extracted to @first_path.
292 unix_create_hardlinks(const struct wim_inode *inode,
293 const char *first_path, struct unix_apply_ctx *ctx)
295 const struct wim_dentry *dentry;
298 inode_for_each_extraction_alias(dentry, inode) {
299 if (dentry == inode_first_extraction_dentry(inode))
301 newpath = unix_build_extraction_path(dentry, ctx);
303 if (link(first_path, newpath)) {
304 if (errno == EEXIST && !unlink(newpath))
306 ERROR_WITH_ERRNO("Can't create hard link "
307 "\"%s\" => \"%s\"", newpath, first_path);
308 return WIMLIB_ERR_LINK;
310 unix_reuse_pathbuf(ctx);
316 unix_create_directory(const struct wim_dentry *dentry,
317 struct unix_apply_ctx *ctx)
319 const char *path = unix_build_extraction_path(dentry, ctx);
322 if (mkdir(path, 0755) &&
323 /* It's okay if the path already exists, as long as it's a
325 !(errno == EEXIST && !lstat(path, &stbuf) && S_ISDIR(stbuf.st_mode)))
327 ERROR_WITH_ERRNO("Can't create directory \"%s\"", path);
328 return WIMLIB_ERR_MKDIR;
335 unix_create_nondirectory(const struct wim_inode *inode,
336 struct unix_apply_ctx *ctx)
338 const char *path = unix_build_inode_extraction_path(inode, ctx);
339 struct wimlib_unix_data unix_data;
341 /* Recognize special files in UNIX_DATA mode */
342 if ((ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_UNIX_DATA) &&
343 inode_get_unix_data(inode, &unix_data) &&
344 !S_ISREG(unix_data.mode))
347 if (mknod(path, unix_data.mode, unix_data.rdev)) {
348 if (errno == EPERM) {
349 WARNING_WITH_ERRNO("Can't create special "
350 "file \"%s\"", path);
351 ctx->num_special_files_ignored++;
354 if (errno == EEXIST && !unlink(path))
356 ERROR_WITH_ERRNO("Can't create special file \"%s\"",
358 return WIMLIB_ERR_MKNOD;
364 fd = open(path, O_EXCL | O_CREAT | O_WRONLY | O_NOFOLLOW, 0644);
366 if (errno == EEXIST && !unlink(path))
368 ERROR_WITH_ERRNO("Can't create regular file \"%s\"", path);
369 return WIMLIB_ERR_OPEN;
372 ERROR_WITH_ERRNO("Error closing \"%s\"", path);
373 return WIMLIB_ERR_WRITE;
377 return unix_create_hardlinks(inode, path, ctx);
380 /* Create all files (and directories) except for symlinks. */
382 unix_create_file_structure(const struct list_head *dentry_list,
383 struct unix_apply_ctx *ctx)
385 const struct wim_dentry *dentry;
386 const struct wim_inode *inode;
389 list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
390 inode = dentry->d_inode;
391 if (!should_extract_as_directory(inode))
393 ret = unix_create_directory(dentry, ctx);
395 ret = report_file_created(&ctx->common);
399 list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
400 inode = dentry->d_inode;
401 if (should_extract_as_directory(inode) ||
402 inode_is_symlink(inode) ||
403 dentry != inode_first_extraction_dentry(inode))
405 ret = unix_create_nondirectory(inode, ctx);
407 ret = report_file_created(&ctx->common);
415 unix_count_inodes(const struct list_head *dentry_list,
416 u64 *full_count, u64 *symlink_count)
418 const struct wim_dentry *dentry;
423 list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
424 if (dentry != inode_first_extraction_dentry(dentry->d_inode))
427 if (inode_is_symlink(dentry->d_inode))
433 unix_create_symlink(const struct wim_inode *inode, const char *path,
434 size_t rpdatalen, struct unix_apply_ctx *ctx)
436 char target[REPARSE_POINT_MAX_SIZE];
437 struct blob_descriptor blob_override;
440 blob_set_is_located_in_attached_buffer(&blob_override,
441 ctx->reparse_data, rpdatalen);
443 ret = wim_inode_readlink(inode, target, sizeof(target) - 1,
446 ctx->target_abspath_nchars);
447 if (unlikely(ret < 0)) {
449 return WIMLIB_ERR_READLINK;
454 if (symlink(target, path)) {
455 if (errno == EEXIST && !unlink(path))
457 return WIMLIB_ERR_LINK;
463 unix_cleanup_open_fds(struct unix_apply_ctx *ctx, unsigned offset)
465 for (unsigned i = offset; i < ctx->num_open_fds; i++)
466 filedes_close(&ctx->open_fds[i]);
467 ctx->num_open_fds = 0;
468 ctx->any_sparse_files = false;
472 unix_begin_extract_blob_instance(const struct blob_descriptor *blob,
473 const struct wim_inode *inode,
474 const struct wim_inode_stream *strm,
475 struct unix_apply_ctx *ctx)
477 const char *path = unix_build_inode_extraction_path(inode, ctx);
480 if (unlikely(strm->stream_type == STREAM_TYPE_REPARSE_POINT)) {
481 /* On UNIX, symbolic links must be created with symlink(), which
482 * requires that the full link target be available. */
483 if (blob->size > REPARSE_DATA_MAX_SIZE) {
484 ERROR_WITH_ERRNO("Reparse data of \"%s\" has size "
485 "%"PRIu64" bytes (exceeds %u bytes)",
487 blob->size, REPARSE_DATA_MAX_SIZE);
488 return WIMLIB_ERR_INVALID_REPARSE_DATA;
490 ctx->reparse_ptr = ctx->reparse_data;
494 wimlib_assert(stream_is_unnamed_data_stream(strm));
496 /* Unnamed data stream of "regular" file */
498 /* This should be ensured by extract_blob_list() */
499 wimlib_assert(ctx->num_open_fds < MAX_OPEN_FILES);
501 fd = open(path, O_WRONLY | O_NOFOLLOW);
503 ERROR_WITH_ERRNO("Can't open regular file \"%s\"", path);
504 return WIMLIB_ERR_OPEN;
506 if (inode->i_attributes & FILE_ATTRIBUTE_SPARSE_FILE) {
507 ctx->is_sparse_file[ctx->num_open_fds] = true;
508 ctx->any_sparse_files = true;
510 ctx->is_sparse_file[ctx->num_open_fds] = false;
511 #ifdef HAVE_POSIX_FALLOCATE
512 posix_fallocate(fd, 0, blob->size);
515 filedes_init(&ctx->open_fds[ctx->num_open_fds++], fd);
519 /* Called when starting to read a blob for extraction */
521 unix_begin_extract_blob(struct blob_descriptor *blob, void *_ctx)
523 struct unix_apply_ctx *ctx = _ctx;
524 const struct blob_extraction_target *targets = blob_extraction_targets(blob);
526 for (u32 i = 0; i < blob->out_refcnt; i++) {
527 int ret = unix_begin_extract_blob_instance(blob,
532 ctx->reparse_ptr = NULL;
533 unix_cleanup_open_fds(ctx, 0);
540 /* Called when the next chunk of a blob has been read for extraction */
542 unix_extract_chunk(const struct blob_descriptor *blob, u64 offset,
543 const void *chunk, size_t size, void *_ctx)
545 struct unix_apply_ctx *ctx = _ctx;
546 const void * const end = chunk + size;
554 * For sparse files, only write nonzero regions. This lets the
555 * filesystem use holes to represent zero regions.
557 for (p = chunk; p != end; p += len, offset += len) {
558 zeroes = maybe_detect_sparse_region(p, end - p, &len,
559 ctx->any_sparse_files);
560 for (i = 0; i < ctx->num_open_fds; i++) {
561 if (!zeroes || !ctx->is_sparse_file[i]) {
562 ret = full_pwrite(&ctx->open_fds[i],
570 if (ctx->reparse_ptr)
571 ctx->reparse_ptr = mempcpy(ctx->reparse_ptr, chunk, size);
575 ERROR_WITH_ERRNO("Error writing data to filesystem");
579 /* Called when a blob has been fully read for extraction */
581 unix_end_extract_blob(struct blob_descriptor *blob, int status, void *_ctx)
583 struct unix_apply_ctx *ctx = _ctx;
586 const struct blob_extraction_target *targets = blob_extraction_targets(blob);
588 ctx->reparse_ptr = NULL;
591 unix_cleanup_open_fds(ctx, 0);
597 for (u32 i = 0; i < blob->out_refcnt; i++) {
598 struct wim_inode *inode = targets[i].inode;
600 if (inode_is_symlink(inode)) {
601 /* We finally have the symlink data, so we can create
605 path = unix_build_inode_extraction_path(inode, ctx);
606 ret = unix_create_symlink(inode, path, blob->size, ctx);
608 ERROR_WITH_ERRNO("Can't create symbolic link "
613 struct filedes *fd = &ctx->open_fds[j];
615 /* If the file is sparse, extend it to its final size. */
616 if (ctx->is_sparse_file[j] && ftruncate(fd->fd, blob->size)) {
617 ERROR_WITH_ERRNO("Error extending \"%s\" to final size",
618 unix_build_inode_extraction_path(inode, ctx));
619 ret = WIMLIB_ERR_WRITE;
623 if (filedes_close(fd)) {
624 ERROR_WITH_ERRNO("Error closing \"%s\"",
625 unix_build_inode_extraction_path(inode, ctx));
626 ret = WIMLIB_ERR_WRITE;
632 unix_cleanup_open_fds(ctx, j);
636 /* Apply metadata to all extracted files (and directories). */
638 unix_apply_metadata(struct list_head *dentry_list, struct unix_apply_ctx *ctx)
640 const struct wim_dentry *dentry;
641 const struct wim_inode *inode;
644 list_for_each_entry_reverse(dentry, dentry_list, d_extraction_list_node)
646 inode = dentry->d_inode;
647 if (dentry != inode_first_extraction_dentry(inode))
649 ret = unix_set_metadata(inode, ctx);
651 ret = report_file_metadata_applied(&ctx->common);
659 unix_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
662 struct unix_apply_ctx *ctx = (struct unix_apply_ctx *)_ctx;
667 /* Compute the maximum path length that will be needed, then allocate
668 * some path buffers. */
669 path_max = unix_compute_path_max(dentry_list, ctx);
671 for (unsigned i = 0; i < NUM_PATHBUFS; i++) {
672 ctx->pathbufs[i] = MALLOC(path_max);
673 if (!ctx->pathbufs[i]) {
674 ret = WIMLIB_ERR_NOMEM;
677 /* Pre-fill the target in each path buffer. We'll just append
678 * the rest of the paths after this. */
679 memcpy(ctx->pathbufs[i],
680 ctx->common.target, ctx->common.target_nchars);
684 * We do the extraction in three phases:
686 * 1. Create all directories and files except for symlinks
690 * In phase (2), the streams which may be extracted include unnamed data
691 * streams (regular file contents), reparse streams (translated to
692 * symlink targets), and extended attribute (xattr) streams. These may
693 * come up for extraction in any order. Therefore, at least when xattr
694 * streams are present, all files must be created earlier, in phase (1).
696 * Symlinks are an exception: they cannot be created until the reparse
697 * stream comes up for extraction. Currently we hack around this by
698 * caching the xattrs of symlinks in memory until they can be applied
699 * between phases (2) and (3).
701 * Note that phase (3) must happen after all data all xattr extraction
702 * because it might set the file mode's to readonly (which precludes
703 * setxattr), and it also will set timestamps including the last
704 * modification time (which precludes write).
707 unix_count_inodes(dentry_list, &full_count, &symlink_count);
709 ret = start_file_structure_phase(&ctx->common,
710 full_count - symlink_count);
714 ret = unix_create_file_structure(dentry_list, ctx);
718 ret = end_file_structure_phase(&ctx->common);
722 /* Get full path to target if needed for absolute symlink fixups. */
723 if ((ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_RPFIX) &&
724 ctx->common.required_features.symlink_reparse_points)
726 ctx->target_abspath = realpath(ctx->common.target, NULL);
727 if (!ctx->target_abspath) {
728 ret = WIMLIB_ERR_NOMEM;
731 ctx->target_abspath_nchars = strlen(ctx->target_abspath);
734 struct read_blob_callbacks cbs = {
735 .begin_blob = unix_begin_extract_blob,
736 .continue_blob = unix_extract_chunk,
737 .end_blob = unix_end_extract_blob,
740 ret = extract_blob_list(&ctx->common, &cbs);
744 ret = start_file_metadata_phase(&ctx->common, full_count);
748 ret = unix_apply_metadata(dentry_list, ctx);
752 ret = end_file_metadata_phase(&ctx->common);
756 if (ctx->num_special_files_ignored) {
757 WARNING("%lu special files were not extracted due to EPERM!",
758 ctx->num_special_files_ignored);
761 for (unsigned i = 0; i < NUM_PATHBUFS; i++)
762 FREE(ctx->pathbufs[i]);
763 FREE(ctx->target_abspath);
767 const struct apply_operations unix_apply_ops = {
769 .get_supported_features = unix_get_supported_features,
770 .extract = unix_extract,
771 .context_size = sizeof(struct unix_apply_ctx),