From 391aa5222080e7544aa82905980f39870ffc6cba Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 22 May 2013 18:12:23 -0500 Subject: [PATCH] Rearrange struct wim_inode and improve comments --- include/wimlib/dentry.h | 180 ++++++++++++++++++++++++---------------- src/dentry.c | 12 +-- src/extract.c | 11 +-- src/hardlink.c | 24 +++--- 4 files changed, 131 insertions(+), 96 deletions(-) diff --git a/include/wimlib/dentry.h b/include/wimlib/dentry.h index daf92a78..0871edc2 100644 --- a/include/wimlib/dentry.h +++ b/include/wimlib/dentry.h @@ -238,104 +238,142 @@ struct wim_dentry { /* * WIM inode. * - * As mentioned above, in the WIM file that is no on-disk analogue of a real - * inode, as most of these fields are duplicated in the dentries. + * As mentioned in the comment above `struct wim_dentry', in the WIM file that + * is no on-disk analogue of a real inode, as most of these fields are + * duplicated in the dentries. Instead, a `struct wim_inode' is something we + * create ourselves to simplify the handling of hard links. */ struct wim_inode { - /* Timestamps for the inode. The timestamps are the number of - * 100-nanosecond intervals that have elapsed since 12:00 A.M., January - * 1st, 1601, UTC. This is the same format used in NTFS inodes. */ - u64 i_creation_time; - u64 i_last_access_time; - u64 i_last_write_time; + /* If i_resolved == 0: + * SHA1 message digest of the contents of the unnamed-data stream + * of this inode. + * + * If i_resolved == 1: + * Pointer to the lookup table entry for the unnamed data stream + * of this inode, or NULL. + * + * i_hash corresponds to the 'unnamed_stream_hash' field of the `struct + * wim_dentry_on_disk' and the additional caveats documented about that + * field apply here (for example, the quirks regarding all-zero hashes). + */ + union { + u8 i_hash[SHA1_HASH_SIZE]; + struct wim_lookup_table_entry *i_lte; + }; - /* The file attributes associated with this inode. This is a bitwise OR - * of the FILE_ATTRIBUTE_* flags. */ + /* Corresponds to the 'attributes' field of `struct wim_dentry_on_disk'; + * bitwise OR of the FILE_ATTRIBUTE_* flags that give the attributes of + * this inode. */ u32 i_attributes; - /* The index of the security descriptor in the WIM image's table of - * security descriptors that contains this file's security information. - * If -1, no security information exists for this file. */ - int32_t i_security_id; + /* Root of a red-black tree storing the child dentries of this inode, if + * any. Keyed by wim_dentry->file_name, case sensitively. */ + struct rb_root i_children; - /* %true iff the inode's lookup table entries has been resolved (i.e. - * the @lte field is valid, but the @hash field is not valid) - * - * (This is not an on-disk field.) */ - u8 i_resolved : 1; +#ifdef __WIN32__ + /* Root of a red-black tree storing the children of this inode, if any. + * Keyed by wim_dentry->file_name, case insensitively. */ + struct rb_root i_children_case_insensitive; +#endif - u8 i_visited : 1; + /* List of dentries that are aliases for this inode. There will be + * i_nlink dentries in this list. */ + struct list_head i_dentry; - /* Used only in NTFS-mode extraction */ - u8 i_dos_name_extracted : 1; + /* Field to place this inode into a list. */ + union { + /* Hash list node- used in hardlink.c when the inodes are placed + * into a hash table keyed by inode number and optionally device + * number, in order to detect dentries that are aliases for the + * same inode. */ + struct hlist_node i_hlist; - /* Set to 0 if reparse point fixups have been done. Otherwise set to 1. - * - * Note: this actually may reflect the SYMBOLIC_LINK_RELATIVE flag. */ - u16 i_not_rpfixed; + /* Normal list node- used to connect all the inodes of a WIM image + * into a single linked list referenced from the + * `struct wim_image_metadata' for that image. */ + struct list_head i_list; + }; + + /* Number of dentries that are aliases for this inode. */ + u32 i_nlink; /* Number of alternate data streams associated with this inode */ u16 i_num_ads; - /* Unused/unknown fields that we just read into memory so we can - * re-write them unchanged. */ - u32 i_rp_unknown_1; - u16 i_rp_unknown_2; + /* Flag that indicates whether this inode's streams have been + * "resolved". By default, the inode starts as "unresolved", meaning + * that the i_hash field, along with the hash field of any associated + * wim_ads_entry's, are valid and should be used as keys in the WIM + * lookup table to find the associated `struct wim_lookup_table_entry'. + * But if the inode has been resolved, then each of these fields is + * replaced with a pointer directly to the appropriate `struct + * wim_lookup_table_entry', or NULL if the stream is empty. */ + u8 i_resolved : 1; - /* If i_resolved == 0: - * SHA1 message digest of the contents of the unnamed-data stream - * of this inode, or all zeroes if this inode has no unnamed data - * stream, or optionally all zeroes if this inode has an empty - * unnamed data stream. - * - * If i_resolved == 1: - * Pointer to the lookup table entry for the unnamed data stream - * of this inode, or NULL if this inode has no unnamed data stream, - * or optionally all zeroes if this inode has an empty unnamed data - * stream. - */ - union { - u8 i_hash[SHA1_HASH_SIZE]; - struct wim_lookup_table_entry *i_lte; - }; + /* Flag used to mark this inode as visited; this is used when visiting + * all the inodes in a dentry tree exactly once. It will be 0 by + * default and must be cleared following the tree traversal, even in + * error paths. */ + u8 i_visited : 1; + + /* For NTFS-3g extraction: Set after the DOS name for this inode has + * been extracted. */ + u8 i_dos_name_extracted : 1; + + /* Pointer to a malloc()ed array of i_num_ads alternate data stream + * entries for this inode. */ + struct wim_ads_entry *i_ads_entries; + + /* Creation time, last access time, and last write time for this inode, in + * 100-nanosecond intervals since 12:00 a.m UTC January 1, 1601. They + * should correspond to the times gotten by calling GetFileTime() on + * Windows. */ + u64 i_creation_time; + u64 i_last_access_time; + u64 i_last_write_time; + + /* Corresponds to 'security_id' in `struct wim_dentry_on_disk': The + * index of this inode's security descriptor in the WIM image's table of + * security descriptors, or -1. Note: in verify_inode(), called + * whenever a WIM image is loaded, out-of-bounds indices are set to -1, + * so the extraction code does not need to do bounds checks. */ + int32_t i_security_id; /* Identity of a reparse point. See * http://msdn.microsoft.com/en-us/library/windows/desktop/aa365503(v=vs.85).aspx * for what a reparse point is. */ u32 i_reparse_tag; - /* Number of dentries that reference this inode */ - u32 i_nlink; + /* Unused/unknown fields that we just read into memory so we can + * re-write them unchanged. */ + u32 i_rp_unknown_1; + u16 i_rp_unknown_2; - /* Alternate data stream entries. */ - struct wim_ads_entry *i_ads_entries; + /* Corresponds to not_rpfixed in `struct wim_dentry_on_disk': Set to 0 + * if reparse point fixups have been done. Otherwise set to 1. Note: + * this actually may reflect the SYMBOLIC_LINK_RELATIVE flag. + */ + u16 i_not_rpfixed; - /* Inode number */ + /* Inode number; corresponds to hard_link_group_id in the `struct + * wim_dentry_on_disk'. */ u64 i_ino; - /* Device number, used only during image capture */ - u64 i_devno; - - /* List of dentries that reference this inode (there should be i_nlink - * of them) */ - struct list_head i_dentry; - union { - struct hlist_node i_hlist; - struct list_head i_list; + /* Device number, used only during image capture, so we can + * identify hard linked files by the combination of inode number + * and device number (rather than just inode number, which could + * be ambigious if the captured tree spans a mountpoint). Set + * to 0 otherwise. */ + u64 i_devno; + + /* Used only during image extraction: pointer to the first path + * (malloc()ed buffer) at which this inode has been extracted. + * Freed and set to NULL after the extraction is done (either + * success or failure). */ + tchar *i_extracted_file; }; - tchar *i_extracted_file; - - /* Root of a red-black tree storing the children of this inode (if - * non-empty, implies the inode is a directory, although that is also - * noted in the @attributes field.) */ - struct rb_root i_children; - -#ifdef __WIN32__ - struct rb_root i_children_case_insensitive; -#endif - /* Next alternate data stream ID to be assigned */ u32 i_next_stream_id; diff --git a/src/dentry.c b/src/dentry.c index 86cbd348..d6eb8a5c 100644 --- a/src/dentry.c +++ b/src/dentry.c @@ -110,16 +110,13 @@ struct wim_dentry_on_disk { le64 unused_1; le64 unused_2; - /* The following three time fields should correspond to those gotten by - * calling GetFileTime() on Windows. */ - /* Creation time, in 100-nanosecond intervals since January 1, 1601. */ + /* Creation time, last access time, and last write time, in + * 100-nanosecond intervals since 12:00 a.m UTC January 1, 1601. They + * should correspond to the times gotten by calling GetFileTime() on + * Windows. */ le64 creation_time; - - /* Last access time, in 100-nanosecond intervals since January 1, 1601. */ le64 last_access_time; - - /* Last write time, in 100-nanosecond intervals since January 1, 1601. */ le64 last_write_time; /* Vaguely, the SHA-1 message digest ("hash") of the file's contents. @@ -1140,7 +1137,6 @@ free_inode(struct wim_inode *inode) * hlist_del() behaves the same as list_del(). */ if (!hlist_unhashed(&inode->i_hlist)) hlist_del(&inode->i_hlist); - FREE(inode->i_extracted_file); FREE(inode); } } diff --git a/src/extract.c b/src/extract.c index f9c4ee98..3e0e6af3 100644 --- a/src/extract.c +++ b/src/extract.c @@ -634,13 +634,14 @@ skip_dentry: static int dentry_reset_needs_extraction(struct wim_dentry *dentry, void *_ignore) { + struct wim_inode *inode = dentry->d_inode; + dentry->needs_extraction = 0; dentry->not_extracted = 0; - dentry->is_win32_name = 0; - dentry->d_inode->i_visited = 0; - dentry->d_inode->i_dos_name_extracted = 0; - FREE(dentry->d_inode->i_extracted_file); - dentry->d_inode->i_extracted_file = NULL; + inode->i_visited = 0; + inode->i_dos_name_extracted = 0; + FREE(inode->i_extracted_file); + inode->i_extracted_file = NULL; if ((void*)dentry->extraction_name != (void*)dentry->file_name) FREE(dentry->extraction_name); dentry->extraction_name = NULL; diff --git a/src/hardlink.c b/src/hardlink.c index 461c9523..47553440 100644 --- a/src/hardlink.c +++ b/src/hardlink.c @@ -581,31 +581,31 @@ void inode_table_prepare_inode_list(struct wim_inode_table *table, struct list_head *head) { - struct wim_inode *inode; + struct wim_inode *inode, *tmp_inode; struct hlist_node *cur, *tmp; u64 cur_ino = 1; /* Re-assign inode numbers in the existing list to avoid duplicates. */ - list_for_each_entry(inode, head, i_list) { - if (inode->i_nlink > 1) - inode->i_ino = cur_ino++; - else - inode->i_ino = 0; - } + list_for_each_entry(inode, head, i_list) + inode->i_ino = cur_ino++; /* Assign inode numbers to the new inodes and move them to the image's * inode list. */ for (size_t i = 0; i < table->capacity; i++) { hlist_for_each_entry_safe(inode, cur, tmp, &table->array[i], i_hlist) { - if (inode->i_nlink > 1) - inode->i_ino = cur_ino++; - else - inode->i_ino = 0; + inode->i_ino = cur_ino++; + inode->i_devno = 0; list_add_tail(&inode->i_list, head); } INIT_HLIST_HEAD(&table->array[i]); } - list_splice_tail(&table->extra_inodes, head); + list_for_each_entry_safe(inode, tmp_inode, &table->extra_inodes, i_list) + { + inode->i_ino = cur_ino++; + inode->i_devno = 0; + list_add_tail(&inode->i_list, head); + } + INIT_LIST_HEAD(&table->extra_inodes); table->num_entries = 0; } -- 2.43.0