diff options
Diffstat (limited to 'fs/ntfs/attrib.c')
| -rw-r--r-- | fs/ntfs/attrib.c | 1258 |
1 files changed, 1258 insertions, 0 deletions
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c new file mode 100644 index 0000000..1ff7f90 --- /dev/null +++ b/fs/ntfs/attrib.c @@ -0,0 +1,1258 @@ +/** + * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project. + * + * Copyright (c) 2001-2004 Anton Altaparmakov + * Copyright (c) 2002 Richard Russon + * + * This program/include file is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program/include file is distributed in the hope that it will be + * useful, but WITHOUT ANY WARRANTY; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program (in the main directory of the Linux-NTFS + * distribution in the file COPYING); if not, write to the Free Software + * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/buffer_head.h> + +#include "attrib.h" +#include "debug.h" +#include "layout.h" +#include "mft.h" +#include "ntfs.h" +#include "types.h" + +/** + * ntfs_map_runlist - map (a part of) a runlist of an ntfs inode + * @ni: ntfs inode for which to map (part of) a runlist + * @vcn: map runlist part containing this vcn + * + * Map the part of a runlist containing the @vcn of the ntfs inode @ni. + * + * Return 0 on success and -errno on error. + * + * Locking: - The runlist must be unlocked on entry and is unlocked on return. + * - This function takes the lock for writing and modifies the runlist. + */ +int ntfs_map_runlist(ntfs_inode *ni, VCN vcn) +{ + ntfs_inode *base_ni; + ntfs_attr_search_ctx *ctx; + MFT_RECORD *mrec; + int err = 0; + + ntfs_debug("Mapping runlist part containing vcn 0x%llx.", + (unsigned long long)vcn); + + if (!NInoAttr(ni)) + base_ni = ni; + else + base_ni = ni->ext.base_ntfs_ino; + + mrec = map_mft_record(base_ni); + if (IS_ERR(mrec)) + return PTR_ERR(mrec); + ctx = ntfs_attr_get_search_ctx(base_ni, mrec); + if (unlikely(!ctx)) { + err = -ENOMEM; + goto err_out; + } + err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, + CASE_SENSITIVE, vcn, NULL, 0, ctx); + if (unlikely(err)) + goto put_err_out; + + down_write(&ni->runlist.lock); + /* Make sure someone else didn't do the work while we were sleeping. */ + if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <= + LCN_RL_NOT_MAPPED)) { + runlist_element *rl; + + rl = ntfs_mapping_pairs_decompress(ni->vol, ctx->attr, + ni->runlist.rl); + if (IS_ERR(rl)) + err = PTR_ERR(rl); + else + ni->runlist.rl = rl; + } + up_write(&ni->runlist.lock); + +put_err_out: + ntfs_attr_put_search_ctx(ctx); +err_out: + unmap_mft_record(base_ni); + return err; +} + +/** + * ntfs_find_vcn - find a vcn in the runlist described by an ntfs inode + * @ni: ntfs inode describing the runlist to search + * @vcn: vcn to find + * @need_write: if false, lock for reading and if true, lock for writing + * + * Find the virtual cluster number @vcn in the runlist described by the ntfs + * inode @ni and return the address of the runlist element containing the @vcn. + * The runlist is left locked and the caller has to unlock it. If @need_write + * is true, the runlist is locked for writing and if @need_write is false, the + * runlist is locked for reading. In the error case, the runlist is not left + * locked. + * + * Note you need to distinguish between the lcn of the returned runlist element + * being >= 0 and LCN_HOLE. In the later case you have to return zeroes on + * read and allocate clusters on write. + * + * Return the runlist element containing the @vcn on success and + * ERR_PTR(-errno) on error. You need to test the return value with IS_ERR() + * to decide if the return is success or failure and PTR_ERR() to get to the + * error code if IS_ERR() is true. + * + * The possible error return codes are: + * -ENOENT - No such vcn in the runlist, i.e. @vcn is out of bounds. + * -ENOMEM - Not enough memory to map runlist. + * -EIO - Critical error (runlist/file is corrupt, i/o error, etc). + * + * Locking: - The runlist must be unlocked on entry. + * - On failing return, the runlist is unlocked. + * - On successful return, the runlist is locked. If @need_write us + * true, it is locked for writing. Otherwise is is locked for + * reading. + */ +runlist_element *ntfs_find_vcn(ntfs_inode *ni, const VCN vcn, + const BOOL need_write) +{ + runlist_element *rl; + int err = 0; + BOOL is_retry = FALSE; + + ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, lock for %sing.", + ni->mft_no, (unsigned long long)vcn, + !need_write ? "read" : "writ"); + BUG_ON(!ni); + BUG_ON(!NInoNonResident(ni)); + BUG_ON(vcn < 0); +lock_retry_remap: + if (!need_write) + down_read(&ni->runlist.lock); + else + down_write(&ni->runlist.lock); + rl = ni->runlist.rl; + if (likely(rl && vcn >= rl[0].vcn)) { + while (likely(rl->length)) { + if (likely(vcn < rl[1].vcn)) { + if (likely(rl->lcn >= LCN_HOLE)) { + ntfs_debug("Done."); + return rl; + } + break; + } + rl++; + } + if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) { + if (likely(rl->lcn == LCN_ENOENT)) + err = -ENOENT; + else + err = -EIO; + } + } + if (!need_write) + up_read(&ni->runlist.lock); + else + up_write(&ni->runlist.lock); + if (!err && !is_retry) { + /* + * The @vcn is in an unmapped region, map the runlist and + * retry. + */ + err = ntfs_map_runlist(ni, vcn); + if (likely(!err)) { + is_retry = TRUE; + goto lock_retry_remap; + } + /* + * -EINVAL and -ENOENT coming from a failed mapping attempt are + * equivalent to i/o errors for us as they should not happen in + * our code paths. + */ + if (err == -EINVAL || err == -ENOENT) + err = -EIO; + } else if (!err) + err = -EIO; + ntfs_error(ni->vol->sb, "Failed with error code %i.", err); + return ERR_PTR(err); +} + +/** + * ntfs_attr_find - find (next) attribute in mft record + * @type: attribute type to find + * @name: attribute name to find (optional, i.e. NULL means don't care) + * @name_len: attribute name length (only needed if @name present) + * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) + * @val: attribute value to find (optional, resident attributes only) + * @val_len: attribute value length + * @ctx: search context with mft record and attribute to search from + * + * You should not need to call this function directly. Use ntfs_attr_lookup() + * instead. + * + * ntfs_attr_find() takes a search context @ctx as parameter and searches the + * mft record specified by @ctx->mrec, beginning at @ctx->attr, for an + * attribute of @type, optionally @name and @val. + * + * If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will + * point to the found attribute. + * + * If the attribute is not found, ntfs_attr_find() returns -ENOENT and + * @ctx->attr will point to the attribute before which the attribute being + * searched for would need to be inserted if such an action were to be desired. + * + * On actual error, ntfs_attr_find() returns -EIO. In this case @ctx->attr is + * undefined and in particular do not rely on it not changing. + * + * If @ctx->is_first is TRUE, the search begins with @ctx->attr itself. If it + * is FALSE, the search begins after @ctx->attr. + * + * If @ic is IGNORE_CASE, the @name comparisson is not case sensitive and + * @ctx->ntfs_ino must be set to the ntfs inode to which the mft record + * @ctx->mrec belongs. This is so we can get at the ntfs volume and hence at + * the upcase table. If @ic is CASE_SENSITIVE, the comparison is case + * sensitive. When @name is present, @name_len is the @name length in Unicode + * characters. + * + * If @name is not present (NULL), we assume that the unnamed attribute is + * being searched for. + * + * Finally, the resident attribute value @val is looked for, if present. If + * @val is not present (NULL), @val_len is ignored. + * + * ntfs_attr_find() only searches the specified mft record and it ignores the + * presence of an attribute list attribute (unless it is the one being searched + * for, obviously). If you need to take attribute lists into consideration, + * use ntfs_attr_lookup() instead (see below). This also means that you cannot + * use ntfs_attr_find() to search for extent records of non-resident + * attributes, as extents with lowest_vcn != 0 are usually described by the + * attribute list attribute only. - Note that it is possible that the first + * extent is only in the attribute list while the last extent is in the base + * mft record, so do not rely on being able to find the first extent in the + * base mft record. + * + * Warning: Never use @val when looking for attribute types which can be + * non-resident as this most likely will result in a crash! + */ +static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name, + const u32 name_len, const IGNORE_CASE_BOOL ic, + const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx) +{ + ATTR_RECORD *a; + ntfs_volume *vol = ctx->ntfs_ino->vol; + ntfschar *upcase = vol->upcase; + u32 upcase_len = vol->upcase_len; + + /* + * Iterate over attributes in mft record starting at @ctx->attr, or the + * attribute following that, if @ctx->is_first is TRUE. + */ + if (ctx->is_first) { + a = ctx->attr; + ctx->is_first = FALSE; + } else + a = (ATTR_RECORD*)((u8*)ctx->attr + + le32_to_cpu(ctx->attr->length)); + for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) { + if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec + + le32_to_cpu(ctx->mrec->bytes_allocated)) + break; + ctx->attr = a; + if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) || + a->type == AT_END)) + return -ENOENT; + if (unlikely(!a->length)) + break; + if (a->type != type) + continue; + /* + * If @name is present, compare the two names. If @name is + * missing, assume we want an unnamed attribute. + */ + if (!name) { + /* The search failed if the found attribute is named. */ + if (a->name_length) + return -ENOENT; + } else if (!ntfs_are_names_equal(name, name_len, + (ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)), + a->name_length, ic, upcase, upcase_len)) { + register int rc; + + rc = ntfs_collate_names(name, name_len, + (ntfschar*)((u8*)a + + le16_to_cpu(a->name_offset)), + a->name_length, 1, IGNORE_CASE, + upcase, upcase_len); + /* + * If @name collates before a->name, there is no + * matching attribute. + */ + if (rc == -1) + return -ENOENT; + /* If the strings are not equal, continue search. */ + if (rc) + continue; + rc = ntfs_collate_names(name, name_len, + (ntfschar*)((u8*)a + + le16_to_cpu(a->name_offset)), + a->name_length, 1, CASE_SENSITIVE, + upcase, upcase_len); + if (rc == -1) + return -ENOENT; + if (rc) + continue; + } + /* + * The names match or @name not present and attribute is + * unnamed. If no @val specified, we have found the attribute + * and are done. + */ + if (!val) + return 0; + /* @val is present; compare values. */ + else { + register int rc; + + rc = memcmp(val, (u8*)a + le16_to_cpu( + a->data.resident.value_offset), + min_t(u32, val_len, le32_to_cpu( + a->data.resident.value_length))); + /* + * If @val collates before the current attribute's + * value, there is no matching attribute. + */ + if (!rc) { + register u32 avl; + + avl = le32_to_cpu( + a->data.resident.value_length); + if (val_len == avl) + return 0; + if (val_len < avl) + return -ENOENT; + } else if (rc < 0) + return -ENOENT; + } + } + ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk."); + NVolSetErrors(vol); + return -EIO; +} + +/** + * load_attribute_list - load an attribute list into memory + * @vol: ntfs volume from which to read + * @runlist: runlist of the attribute list + * @al_start: destination buffer + * @size: size of the destination buffer in bytes + * @initialized_size: initialized size of the attribute list + * + * Walk the runlist @runlist and load all clusters from it copying them into + * the linear buffer @al. The maximum number of bytes copied to @al is @size + * bytes. Note, @size does not need to be a multiple of the cluster size. If + * @initialized_size is less than @size, the region in @al between + * @initialized_size and @size will be zeroed and not read from disk. + * + * Return 0 on success or -errno on error. + */ +int load_attribute_list(ntfs_volume *vol, runlist *runlist, u8 *al_start, + const s64 size, const s64 initialized_size) +{ + LCN lcn; + u8 *al = al_start; + u8 *al_end = al + initialized_size; + runlist_element *rl; + struct buffer_head *bh; + struct super_block *sb; + unsigned long block_size; + unsigned long block, max_block; + int err = 0; + unsigned char block_size_bits; + + ntfs_debug("Entering."); + if (!vol || !runlist || !al || size <= 0 || initialized_size < 0 || + initialized_size > size) + return -EINVAL; + if (!initialized_size) { + memset(al, 0, size); + return 0; + } + sb = vol->sb; + block_size = sb->s_blocksize; + block_size_bits = sb->s_blocksize_bits; + down_read(&runlist->lock); + rl = runlist->rl; + /* Read all clusters specified by the runlist one run at a time. */ + while (rl->length) { + lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn); + ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.", + (unsigned long long)rl->vcn, + (unsigned long long)lcn); + /* The attribute list cannot be sparse. */ + if (lcn < 0) { + ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot " + "read attribute list."); + goto err_out; + } + block = lcn << vol->cluster_size_bits >> block_size_bits; + /* Read the run from device in chunks of block_size bytes. */ + max_block = block + (rl->length << vol->cluster_size_bits >> + block_size_bits); + ntfs_debug("max_block = 0x%lx.", max_block); + do { + ntfs_debug("Reading block = 0x%lx.", block); + bh = sb_bread(sb, block); + if (!bh) { + ntfs_error(sb, "sb_bread() failed. Cannot " + "read attribute list."); + goto err_out; + } + if (al + block_size >= al_end) + goto do_final; + memcpy(al, bh->b_data, block_size); + brelse(bh); + al += block_size; + } while (++block < max_block); + rl++; + } + if (initialized_size < size) { +initialize: + memset(al_start + initialized_size, 0, size - initialized_size); + } +done: + up_read(&runlist->lock); + return err; +do_final: + if (al < al_end) { + /* + * Partial block. + * + * Note: The attribute list can be smaller than its allocation + * by multiple clusters. This has been encountered by at least + * two people running Windows XP, thus we cannot do any + * truncation sanity checking here. (AIA) + */ + memcpy(al, bh->b_data, al_end - al); + brelse(bh); + if (initialized_size < size) + goto initialize; + goto done; + } + brelse(bh); + /* Real overflow! */ + ntfs_error(sb, "Attribute list buffer overflow. Read attribute list " + "is truncated."); +err_out: + err = -EIO; + goto done; +} + +/** + * ntfs_external_attr_find - find an attribute in the attribute list of an inode + * @type: attribute type to find + * @name: attribute name to find (optional, i.e. NULL means don't care) + * @name_len: attribute name length (only needed if @name present) + * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) + * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only) + * @val: attribute value to find (optional, resident attributes only) + * @val_len: attribute value length + * @ctx: search context with mft record and attribute to search from + * + * You should not need to call this function directly. Use ntfs_attr_lookup() + * instead. + * + * Find an attribute by searching the attribute list for the corresponding + * attribute list entry. Having found the entry, map the mft record if the + * attribute is in a different mft record/inode, ntfs_attr_find() the attribute + * in there and return it. + * + * On first search @ctx->ntfs_ino must be the base mft record and @ctx must + * have been obtained from a call to ntfs_attr_get_search_ctx(). On subsequent + * calls @ctx->ntfs_ino can be any extent inode, too (@ctx->base_ntfs_ino is + * then the base inode). + * + * After finishing with the attribute/mft record you need to call + * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any + * mapped inodes, etc). + * + * If the attribute is found, ntfs_external_attr_find() returns 0 and + * @ctx->attr will point to the found attribute. @ctx->mrec will point to the + * mft record in which @ctx->attr is located and @ctx->al_entry will point to + * the attribute list entry for the attribute. + * + * If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and + * @ctx->attr will point to the attribute in the base mft record before which + * the attribute being searched for would need to be inserted if such an action + * were to be desired. @ctx->mrec will point to the mft record in which + * @ctx->attr is located and @ctx->al_entry will point to the attribute list + * entry of the attribute before which the attribute being searched for would + * need to be inserted if such an action were to be desired. + * + * Thus to insert the not found attribute, one wants to add the attribute to + * @ctx->mrec (the base mft record) and if there is not enough space, the + * attribute should be placed in a newly allocated extent mft record. The + * attribute list entry for the inserted attribute should be inserted in the + * attribute list attribute at @ctx->al_entry. + * + * On actual error, ntfs_external_attr_find() returns -EIO. In this case + * @ctx->attr is undefined and in particular do not rely on it not changing. + */ +static int ntfs_external_attr_find(const ATTR_TYPE type, + const ntfschar *name, const u32 name_len, + const IGNORE_CASE_BOOL ic, const VCN lowest_vcn, + const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx) +{ + ntfs_inode *base_ni, *ni; + ntfs_volume *vol; + ATTR_LIST_ENTRY *al_entry, *next_al_entry; + u8 *al_start, *al_end; + ATTR_RECORD *a; + ntfschar *al_name; + u32 al_name_len; + int err = 0; + static const char *es = " Unmount and run chkdsk."; + + ni = ctx->ntfs_ino; + base_ni = ctx->base_ntfs_ino; + ntfs_debug("Entering for inode 0x%lx, type 0x%x.", ni->mft_no, type); + if (!base_ni) { + /* First call happens with the base mft record. */ + base_ni = ctx->base_ntfs_ino = ctx->ntfs_ino; + ctx->base_mrec = ctx->mrec; + } + if (ni == base_ni) + ctx->base_attr = ctx->attr; + if (type == AT_END) + goto not_found; + vol = base_ni->vol; + al_start = base_ni->attr_list; + al_end = al_start + base_ni->attr_list_size; + if (!ctx->al_entry) + ctx->al_entry = (ATTR_LIST_ENTRY*)al_start; + /* + * Iterate over entries in attribute list starting at @ctx->al_entry, + * or the entry following that, if @ctx->is_first is TRUE. + */ + if (ctx->is_first) { + al_entry = ctx->al_entry; + ctx->is_first = FALSE; + } else + al_entry = (ATTR_LIST_ENTRY*)((u8*)ctx->al_entry + + le16_to_cpu(ctx->al_entry->length)); + for (;; al_entry = next_al_entry) { + /* Out of bounds check. */ + if ((u8*)al_entry < base_ni->attr_list || + (u8*)al_entry > al_end) + break; /* Inode is corrupt. */ + ctx->al_entry = al_entry; + /* Catch the end of the attribute list. */ + if ((u8*)al_entry == al_end) + goto not_found; + if (!al_entry->length) + break; + if ((u8*)al_entry + 6 > al_end || (u8*)al_entry + + le16_to_cpu(al_entry->length) > al_end) + break; + next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry + + le16_to_cpu(al_entry->length)); + if (le32_to_cpu(al_entry->type) > le32_to_cpu(type)) + goto not_found; + if (type != al_entry->type) + continue; + /* + * If @name is present, compare the two names. If @name is + * missing, assume we want an unnamed attribute. + */ + al_name_len = al_entry->name_length; + al_name = (ntfschar*)((u8*)al_entry + al_entry->name_offset); + if (!name) { + if (al_name_len) + goto not_found; + } else if (!ntfs_are_names_equal(al_name, al_name_len, name, + name_len, ic, vol->upcase, vol->upcase_len)) { + register int rc; + + rc = ntfs_collate_names(name, name_len, al_name, + al_name_len, 1, IGNORE_CASE, + vol->upcase, vol->upcase_len); + /* + * If @name collates before al_name, there is no + * matching attribute. + */ + if (rc == -1) + goto not_found; + /* If the strings are not equal, continue search. */ + if (rc) + continue; + /* + * FIXME: Reverse engineering showed 0, IGNORE_CASE but + * that is inconsistent with ntfs_attr_find(). The + * subsequent rc checks were also different. Perhaps I + * made a mistake in one of the two. Need to recheck + * which is correct or at least see what is going on... + * (AIA) + */ + rc = ntfs_collate_names(name, name_len, al_name, + al_name_len, 1, CASE_SENSITIVE, + vol->upcase, vol->upcase_len); + if (rc == -1) + goto not_found; + if (rc) + continue; + } + /* + * The names match or @name not present and attribute is + * unnamed. Now check @lowest_vcn. Continue search if the + * next attribute list entry still fits @lowest_vcn. Otherwise + * we have reached the right one or the search has failed. + */ + if (lowest_vcn && (u8*)next_al_entry >= al_start && + (u8*)next_al_entry + 6 < al_end && + (u8*)next_al_entry + le16_to_cpu( + next_al_entry->length) <= al_end && + sle64_to_cpu(next_al_entry->lowest_vcn) <= + lowest_vcn && + next_al_entry->type == al_entry->type && + next_al_entry->name_length == al_name_len && + ntfs_are_names_equal((ntfschar*)((u8*) + next_al_entry + + next_al_entry->name_offset), + next_al_entry->name_length, + al_name, al_name_len, CASE_SENSITIVE, + vol->upcase, vol->upcase_len)) + continue; + if (MREF_LE(al_entry->mft_reference) == ni->mft_no) { + if (MSEQNO_LE(al_entry->mft_reference) != ni->seq_no) { + ntfs_error(vol->sb, "Found stale mft " + "reference in attribute list " + "of base inode 0x%lx.%s", + base_ni->mft_no, es); + err = -EIO; + break; + } + } else { /* Mft references do not match. */ + /* If there is a mapped record unmap it first. */ + if (ni != base_ni) + unmap_extent_mft_record(ni); + /* Do we want the base record back? */ + if (MREF_LE(al_entry->mft_reference) == + base_ni->mft_no) { + ni = ctx->ntfs_ino = base_ni; + ctx->mrec = ctx->base_mrec; + } else { + /* We want an extent record. */ + ctx->mrec = map_extent_mft_record(base_ni, + le64_to_cpu( + al_entry->mft_reference), &ni); + if (IS_ERR(ctx->mrec)) { + ntfs_error(vol->sb, "Failed to map " + "extent mft record " + "0x%lx of base inode " + "0x%lx.%s", + MREF_LE(al_entry-> + mft_reference), + base_ni->mft_no, es); + err = PTR_ERR(ctx->mrec); + if (err == -ENOENT) + err = -EIO; + /* Cause @ctx to be sanitized below. */ + ni = NULL; + break; + } + ctx->ntfs_ino = ni; + } + ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + + le16_to_cpu(ctx->mrec->attrs_offset)); + } + /* + * ctx->vfs_ino, ctx->mrec, and ctx->attr now point to the + * mft record containing the attribute represented by the + * current al_entry. + */ + /* + * We could call into ntfs_attr_find() to find the right + * attribute in this mft record but this would be less + * efficient and not quite accurate as ntfs_attr_find() ignores + * the attribute instance numbers for example which become + * important when one plays with attribute lists. Also, + * because a proper match has been found in the attribute list + * entry above, the comparison can now be optimized. So it is + * worth re-implementing a simplified ntfs_attr_find() here. + */ + a = ctx->attr; + /* + * Use a manual loop so we can still use break and continue + * with the same meanings as above. + */ +do_next_attr_loop: + if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec + + le32_to_cpu(ctx->mrec->bytes_allocated)) + break; + if (a->type == AT_END) + continue; + if (!a->length) + break; + if (al_entry->instance != a->instance) + goto do_next_attr; + /* + * If the type and/or the name are mismatched between the + * attribute list entry and the attribute record, there is + * corruption so we break and return error EIO. + */ + if (al_entry->type != a->type) + break; + if (!ntfs_are_names_equal((ntfschar*)((u8*)a + + le16_to_cpu(a->name_offset)), a->name_length, + al_name, al_name_len, CASE_SENSITIVE, + vol->upcase, vol->upcase_len)) + break; + ctx->attr = a; + /* + * If no @val specified or @val specified and it matches, we + * have found it! + */ + if (!val || (!a->non_resident && le32_to_cpu( + a->data.resident.value_length) == val_len && + !memcmp((u8*)a + + le16_to_cpu(a->data.resident.value_offset), + val, val_len))) { + ntfs_debug("Done, found."); + return 0; + } +do_next_attr: + /* Proceed to the next attribute in the current mft record. */ + a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length)); + goto do_next_attr_loop; + } + if (!err) { + ntfs_error(vol->sb, "Base inode 0x%lx contains corrupt " + "attribute list attribute.%s", base_ni->mft_no, + es); + err = -EIO; + } + if (ni != base_ni) { + if (ni) + unmap_extent_mft_record(ni); + ctx->ntfs_ino = base_ni; + ctx->mrec = ctx->base_mrec; + ctx->attr = ctx->base_attr; + } + if (err != -ENOMEM) + NVolSetErrors(vol); + return err; +not_found: + /* + * If we were looking for AT_END, we reset the search context @ctx and + * use ntfs_attr_find() to seek to the end of the base mft record. + */ + if (type == AT_END) { + ntfs_attr_reinit_search_ctx(ctx); + return ntfs_attr_find(AT_END, name, name_len, ic, val, val_len, + ctx); + } + /* + * The attribute was not found. Before we return, we want to ensure + * @ctx->mrec and @ctx->attr indicate the position at which the + * attribute should be inserted in the base mft record. Since we also + * want to preserve @ctx->al_entry we cannot reinitialize the search + * context using ntfs_attr_reinit_search_ctx() as this would set + * @ctx->al_entry to NULL. Thus we do the necessary bits manually (see + * ntfs_attr_init_search_ctx() below). Note, we _only_ preserve + * @ctx->al_entry as the remaining fields (base_*) are identical to + * their non base_ counterparts and we cannot set @ctx->base_attr + * correctly yet as we do not know what @ctx->attr will be set to by + * the call to ntfs_attr_find() below. + */ + if (ni != base_ni) + unmap_extent_mft_record(ni); + ctx->mrec = ctx->base_mrec; + ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + + le16_to_cpu(ctx->mrec->attrs_offset)); + ctx->is_first = TRUE; + ctx->ntfs_ino = base_ni; + ctx->base_ntfs_ino = NULL; + ctx->base_mrec = NULL; + ctx->base_attr = NULL; + /* + * In case there are multiple matches in the base mft record, need to + * keep enumerating until we get an attribute not found response (or + * another error), otherwise we would keep returning the same attribute + * over and over again and all programs using us for enumeration would + * lock up in a tight loop. + */ + do { + err = ntfs_attr_find(type, name, name_len, ic, val, val_len, + ctx); + } while (!err); + ntfs_debug("Done, not found."); + return err; +} + +/** + * ntfs_attr_lookup - find an attribute in an ntfs inode + * @type: attribute type to find + * @name: attribute name to find (optional, i.e. NULL means don't care) + * @name_len: attribute name length (only needed if @name present) + * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) + * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only) + * @val: attribute value to find (optional, resident attributes only) + * @val_len: attribute value length + * @ctx: search context with mft record and attribute to search from + * + * Find an attribute in an ntfs inode. On first search @ctx->ntfs_ino must + * be the base mft record and @ctx must have been obtained from a call to + * ntfs_attr_get_search_ctx(). + * + * This function transparently handles attribute lists and @ctx is used to + * continue searches where they were left off at. + * + * After finishing with the attribute/mft record you need to call + * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any + * mapped inodes, etc). + * + * Return 0 if the search was successful and -errno if not. + * + * When 0, @ctx->attr is the found attribute and it is in mft record + * @ctx->mrec. If an attribute list attribute is present, @ctx->al_entry is + * the attribute list entry of the found attribute. + * + * When -ENOENT, @ctx->attr is the attribute which collates just after the + * attribute being searched for, i.e. if one wants to add the attribute to the + * mft record this is the correct place to insert it into. If an attribute + * list attribute is present, @ctx->al_entry is the attribute list entry which + * collates just after the attribute list entry of the attribute being searched + * for, i.e. if one wants to add the attribute to the mft record this is the + * correct place to insert its attribute list entry into. + * + * When -errno != -ENOENT, an error occured during the lookup. @ctx->attr is + * then undefined and in particular you should not rely on it not changing. + */ +int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name, + const u32 name_len, const IGNORE_CASE_BOOL ic, + const VCN lowest_vcn, const u8 *val, const u32 val_len, + ntfs_attr_search_ctx *ctx) +{ + ntfs_inode *base_ni; + + ntfs_debug("Entering."); + if (ctx->base_ntfs_ino) + base_ni = ctx->base_ntfs_ino; + else + base_ni = ctx->ntfs_ino; + /* Sanity check, just for debugging really. */ + BUG_ON(!base_ni); + if (!NInoAttrList(base_ni) || type == AT_ATTRIBUTE_LIST) + return ntfs_attr_find(type, name, name_len, ic, val, val_len, + ctx); + return ntfs_external_attr_find(type, name, name_len, ic, lowest_vcn, + val, val_len, ctx); +} + +/** + * ntfs_attr_init_search_ctx - initialize an attribute search context + * @ctx: attribute search context to initialize + * @ni: ntfs inode with which to initialize the search context + * @mrec: mft record with which to initialize the search context + * + * Initialize the attribute search context @ctx with @ni and @mrec. + */ +static inline void ntfs_attr_init_search_ctx(ntfs_attr_search_ctx *ctx, + ntfs_inode *ni, MFT_RECORD *mrec) +{ + ctx->mrec = mrec; + /* Sanity checks are performed elsewhere. */ + ctx->attr = (ATTR_RECORD*)((u8*)mrec + le16_to_cpu(mrec->attrs_offset)); + ctx->is_first = TRUE; + ctx->ntfs_ino = ni; + ctx->al_entry = NULL; + ctx->base_ntfs_ino = NULL; + ctx->base_mrec = NULL; + ctx->base_attr = NULL; +} + +/** + * ntfs_attr_reinit_search_ctx - reinitialize an attribute search context + * @ctx: attribute search context to reinitialize + * + * Reinitialize the attribute search context @ctx, unmapping an associated + * extent mft record if present, and initialize the search context again. + * + * This is used when a search for a new attribute is being started to reset + * the search context to the beginning. + */ +void ntfs_attr_reinit_search_ctx(ntfs_attr_search_ctx *ctx) +{ + if (likely(!ctx->base_ntfs_ino)) { + /* No attribute list. */ + ctx->is_first = TRUE; + /* Sanity checks are performed elsewhere. */ + ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + + le16_to_cpu(ctx->mrec->attrs_offset)); + /* + * This needs resetting due to ntfs_external_attr_find() which + * can leave it set despite having zeroed ctx->base_ntfs_ino. + */ + ctx->al_entry = NULL; + return; + } /* Attribute list. */ + if (ctx->ntfs_ino != ctx->base_ntfs_ino) + unmap_extent_mft_record(ctx->ntfs_ino); + ntfs_attr_init_search_ctx(ctx, ctx->base_ntfs_ino, ctx->base_mrec); + return; +} + +/** + * ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context + * @ni: ntfs inode with which to initialize the search context + * @mrec: mft record with which to initialize the search context + * + * Allocate a new attribute search context, initialize it with @ni and @mrec, + * and return it. Return NULL if allocation failed. + */ +ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec) +{ + ntfs_attr_search_ctx *ctx; + + ctx = kmem_cache_alloc(ntfs_attr_ctx_cache, SLAB_NOFS); + if (ctx) + ntfs_attr_init_search_ctx(ctx, ni, mrec); + return ctx; +} + +/** + * ntfs_attr_put_search_ctx - release an attribute search context + * @ctx: attribute search context to free + * + * Release the attribute search context @ctx, unmapping an associated extent + * mft record if present. + */ +void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx) +{ + if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino) + unmap_extent_mft_record(ctx->ntfs_ino); + kmem_cache_free(ntfs_attr_ctx_cache, ctx); + return; +} + +/** + * ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to find + * + * Search for the attribute definition record corresponding to the attribute + * @type in the $AttrDef system file. + * + * Return the attribute type definition record if found and NULL if not found. + */ +static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol, + const ATTR_TYPE type) +{ + ATTR_DEF *ad; + + BUG_ON(!vol->attrdef); + BUG_ON(!type); + for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef < + vol->attrdef_size && ad->type; ++ad) { + /* We have not found it yet, carry on searching. */ + if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type))) + continue; + /* We found the attribute; return it. */ + if (likely(ad->type == type)) + return ad; + /* We have gone too far already. No point in continuing. */ + break; + } + /* Attribute not found. */ + ntfs_debug("Attribute type 0x%x not found in $AttrDef.", + le32_to_cpu(type)); + return NULL; +} + +/** + * ntfs_attr_size_bounds_check - check a size of an attribute type for validity + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to check + * @size: size which to check + * + * Check whether the @size in bytes is valid for an attribute of @type on the + * ntfs volume @vol. This information is obtained from $AttrDef system file. + * + * Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not + * listed in $AttrDef. + */ +int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type, + const s64 size) +{ + ATTR_DEF *ad; + + BUG_ON(size < 0); + /* + * $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not + * listed in $AttrDef. + */ + if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024)) + return -ERANGE; + /* Get the $AttrDef entry for the attribute @type. */ + ad = ntfs_attr_find_in_attrdef(vol, type); + if (unlikely(!ad)) + return -ENOENT; + /* Do the bounds check. */ + if (((sle64_to_cpu(ad->min_size) > 0) && + size < sle64_to_cpu(ad->min_size)) || + ((sle64_to_cpu(ad->max_size) > 0) && size > + sle64_to_cpu(ad->max_size))) + return -ERANGE; + return 0; +} + +/** + * ntfs_attr_can_be_non_resident - check if an attribute can be non-resident + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to check + * + * Check whether the attribute of @type on the ntfs volume @vol is allowed to + * be non-resident. This information is obtained from $AttrDef system file. + * + * Return 0 if the attribute is allowed to be non-resident, -EPERM if not, or + * -ENOENT if the attribute is not listed in $AttrDef. + */ +int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type) +{ + ATTR_DEF *ad; + + /* + * $DATA is always allowed to be non-resident even if $AttrDef does not + * specify this in the flags of the $DATA attribute definition record. + */ + if (type == AT_DATA) + return 0; + /* Find the attribute definition record in $AttrDef. */ + ad = ntfs_attr_find_in_attrdef(vol, type); + if (unlikely(!ad)) + return -ENOENT; + /* Check the flags and return the result. */ + if (ad->flags & CAN_BE_NON_RESIDENT) + return 0; + return -EPERM; +} + +/** + * ntfs_attr_can_be_resident - check if an attribute can be resident + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to check + * + * Check whether the attribute of @type on the ntfs volume @vol is allowed to + * be resident. This information is derived from our ntfs knowledge and may + * not be completely accurate, especially when user defined attributes are + * present. Basically we allow everything to be resident except for index + * allocation and $EA attributes. + * + * Return 0 if the attribute is allowed to be non-resident and -EPERM if not. + * + * Warning: In the system file $MFT the attribute $Bitmap must be non-resident + * otherwise windows will not boot (blue screen of death)! We cannot + * check for this here as we do not know which inode's $Bitmap is + * being asked about so the caller needs to special case this. + */ +int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type) +{ + if (type != AT_INDEX_ALLOCATION && type != AT_EA) + return 0; + return -EPERM; +} + +/** + * ntfs_attr_record_resize - resize an attribute record + * @m: mft record containing attribute record + * @a: attribute record to resize + * @new_size: new size in bytes to which to resize the attribute record @a + * + * Resize the attribute record @a, i.e. the resident part of the attribute, in + * the mft record @m to @new_size bytes. + * + * Return 0 on success and -errno on error. The following error codes are + * defined: + * -ENOSPC - Not enough space in the mft record @m to perform the resize. + * + * Note: On error, no modifications have been performed whatsoever. + * + * Warning: If you make a record smaller without having copied all the data you + * are interested in the data may be overwritten. + */ +int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size) +{ + ntfs_debug("Entering for new_size %u.", new_size); + /* Align to 8 bytes if it is not already done. */ + if (new_size & 7) + new_size = (new_size + 7) & ~7; + /* If the actual attribute length has changed, move things around. */ + if (new_size != le32_to_cpu(a->length)) { + u32 new_muse = le32_to_cpu(m->bytes_in_use) - + le32_to_cpu(a->length) + new_size; + /* Not enough space in this mft record. */ + if (new_muse > le32_to_cpu(m->bytes_allocated)) + return -ENOSPC; + /* Move attributes following @a to their new location. */ + memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length), + le32_to_cpu(m->bytes_in_use) - ((u8*)a - + (u8*)m) - le32_to_cpu(a->length)); + /* Adjust @m to reflect the change in used space. */ + m->bytes_in_use = cpu_to_le32(new_muse); + /* Adjust @a to reflect the new size. */ + if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length)) + a->length = cpu_to_le32(new_size); + } + return 0; +} + +/** + * ntfs_attr_set - fill (a part of) an attribute with a byte + * @ni: ntfs inode describing the attribute to fill + * @ofs: offset inside the attribute at which to start to fill + * @cnt: number of bytes to fill + * @val: the unsigned 8-bit value with which to fill the attribute + * + * Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at + * byte offset @ofs inside the attribute with the constant byte @val. + * + * This function is effectively like memset() applied to an ntfs attribute. + * + * Return 0 on success and -errno on error. An error code of -ESPIPE means + * that @ofs + @cnt were outside the end of the attribute and no write was + * performed. + */ +int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val) +{ + ntfs_volume *vol = ni->vol; + struct address_space *mapping; + struct page *page; + u8 *kaddr; + pgoff_t idx, end; + unsigned int start_ofs, end_ofs, size; + + ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.", + (long long)ofs, (long long)cnt, val); + BUG_ON(ofs < 0); + BUG_ON(cnt < 0); + if (!cnt) + goto done; + mapping = VFS_I(ni)->i_mapping; + /* Work out the starting index and page offset. */ + idx = ofs >> PAGE_CACHE_SHIFT; + start_ofs = ofs & ~PAGE_CACHE_MASK; + /* Work out the ending index and page offset. */ + end = ofs + cnt; + end_ofs = end & ~PAGE_CACHE_MASK; + /* If the end is outside the inode size return -ESPIPE. */ + if (unlikely(end > VFS_I(ni)->i_size)) { + ntfs_error(vol->sb, "Request exceeds end of attribute."); + return -ESPIPE; + } + end >>= PAGE_CACHE_SHIFT; + /* If there is a first partial page, need to do it the slow way. */ + if (start_ofs) { + page = read_cache_page(mapping, idx, + (filler_t*)mapping->a_ops->readpage, NULL); + if (IS_ERR(page)) { + ntfs_error(vol->sb, "Failed to read first partial " + "page (sync error, index 0x%lx).", idx); + return PTR_ERR(page); + } + wait_on_page_locked(page); + if (unlikely(!PageUptodate(page))) { + ntfs_error(vol->sb, "Failed to read first partial page " + "(async error, index 0x%lx).", idx); + page_cache_release(page); + return PTR_ERR(page); + } + /* + * If the last page is the same as the first page, need to + * limit the write to the end offset. + */ + size = PAGE_CACHE_SIZE; + if (idx == end) + size = end_ofs; + kaddr = kmap_atomic(page, KM_USER0); + memset(kaddr + start_ofs, val, size - start_ofs); + flush_dcache_page(page); + kunmap_atomic(kaddr, KM_USER0); + set_page_dirty(page); + page_cache_release(page); + if (idx == end) + goto done; + idx++; + } + /* Do the whole pages the fast way. */ + for (; idx < end; idx++) { + /* Find or create the current page. (The page is locked.) */ + page = grab_cache_page(mapping, idx); + if (unlikely(!page)) { + ntfs_error(vol->sb, "Insufficient memory to grab " + "page (index 0x%lx).", idx); + return -ENOMEM; + } + kaddr = kmap_atomic(page, KM_USER0); + memset(kaddr, val, PAGE_CACHE_SIZE); + flush_dcache_page(page); + kunmap_atomic(kaddr, KM_USER0); + /* + * If the page has buffers, mark them uptodate since buffer + * state and not page state is definitive in 2.6 kernels. + */ + if (page_has_buffers(page)) { + struct buffer_head *bh, *head; + + bh = head = page_buffers(page); + do { + set_buffer_uptodate(bh); + } while ((bh = bh->b_this_page) != head); + } + /* Now that buffers are uptodate, set the page uptodate, too. */ + SetPageUptodate(page); + /* + * Set the page and all its buffers dirty and mark the inode + * dirty, too. The VM will write the page later on. + */ + set_page_dirty(page); + /* Finally unlock and release the page. */ + unlock_page(page); + page_cache_release(page); + } + /* If there is a last partial page, need to do it the slow way. */ + if (end_ofs) { + page = read_cache_page(mapping, idx, + (filler_t*)mapping->a_ops->readpage, NULL); + if (IS_ERR(page)) { + ntfs_error(vol->sb, "Failed to read last partial page " + "(sync error, index 0x%lx).", idx); + return PTR_ERR(page); + } + wait_on_page_locked(page); + if (unlikely(!PageUptodate(page))) { + ntfs_error(vol->sb, "Failed to read last partial page " + "(async error, index 0x%lx).", idx); + page_cache_release(page); + return PTR_ERR(page); + } + kaddr = kmap_atomic(page, KM_USER0); + memset(kaddr, val, end_ofs); + flush_dcache_page(page); + kunmap_atomic(kaddr, KM_USER0); + set_page_dirty(page); + page_cache_release(page); + } +done: + ntfs_debug("Done."); + return 0; +} |
