litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'net/unix/garbage.c')

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/** * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project. * * Copyright (c) 2001-2005 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 <linux/swap.h> #include "attrib.h" #include "debug.h" #include "layout.h" #include "lcnalloc.h" #include "malloc.h" #include "mft.h" #include "ntfs.h" #include "types.h" /** * ntfs_map_runlist_nolock - 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 * @ctx: active attribute search context if present or NULL if not * * Map the part of a runlist containing the @vcn of the ntfs inode @ni. * * If @ctx is specified, it is an active search context of @ni and its base mft * record. This is needed when ntfs_map_runlist_nolock() encounters unmapped * runlist fragments and allows their mapping. If you do not have the mft * record mapped, you can specify @ctx as NULL and ntfs_map_runlist_nolock() * will perform the necessary mapping and unmapping. * * Note, ntfs_map_runlist_nolock() saves the state of @ctx on entry and * restores it before returning. Thus, @ctx will be left pointing to the same * attribute on return as on entry. However, the actual pointers in @ctx may * point to different memory locations on return, so you must remember to reset * any cached pointers from the @ctx, i.e. after the call to * ntfs_map_runlist_nolock(), you will probably want to do: * m = ctx->mrec; * a = ctx->attr; * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that * you cache ctx->mrec in a variable @m of type MFT_RECORD *. * * Return 0 on success and -errno on error. There is one special error code * which is not an error as such. This is -ENOENT. It means that @vcn is out * of bounds of the runlist. * * Note the runlist can be NULL after this function returns if @vcn is zero and * the attribute has zero allocated size, i.e. there simply is no runlist. * * WARNING: If @ctx is supplied, regardless of whether success or failure is * returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx * is no longer valid, i.e. you need to either call * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it. * In that case PTR_ERR(@ctx->mrec) will give you the error code for * why the mapping of the old inode failed. * * Locking: - The runlist described by @ni must be locked for writing on entry * and is locked on return. Note the runlist will be modified. * - If @ctx is NULL, the base mft record of @ni must not be mapped on * entry and it will be left unmapped on return. * - If @ctx is not NULL, the base mft record must be mapped on entry * and it will be left mapped on return. */ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx) { VCN end_vcn; unsigned long flags; ntfs_inode *base_ni; MFT_RECORD *m; ATTR_RECORD *a; runlist_element *rl; struct page *put_this_page = NULL; int err = 0; BOOL ctx_is_temporary, ctx_needs_reset; ntfs_attr_search_ctx old_ctx; 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; if (!ctx) { ctx_is_temporary = ctx_needs_reset = TRUE; m = map_mft_record(base_ni); if (IS_ERR(m)) return PTR_ERR(m); ctx = ntfs_attr_get_search_ctx(base_ni, m); if (unlikely(!ctx)) { err = -ENOMEM; goto err_out; } } else { VCN allocated_size_vcn; BUG_ON(IS_ERR(ctx->mrec)); a = ctx->attr; BUG_ON(!a->non_resident); ctx_is_temporary = FALSE; end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn); read_lock_irqsave(&ni->size_lock, flags); allocated_size_vcn = ni->allocated_size >> ni->vol->cluster_size_bits; read_unlock_irqrestore(&ni->size_lock, flags); if (!a->data.non_resident.lowest_vcn && end_vcn <= 0) end_vcn = allocated_size_vcn - 1; /* * If we already have the attribute extent containing @vcn in * @ctx, no need to look it up again. We slightly cheat in * that if vcn exceeds the allocated size, we will refuse to * map the runlist below, so there is definitely no need to get * the right attribute extent. */ if (vcn >= allocated_size_vcn || (a->type == ni->type && a->name_length == ni->name_len && !memcmp((u8*)a + le16_to_cpu(a->name_offset), ni->name, ni->name_len) && sle64_to_cpu(a->data.non_resident.lowest_vcn) <= vcn && end_vcn >= vcn)) ctx_needs_reset = FALSE; else { /* Save the old search context. */ old_ctx = *ctx; /* * If the currently mapped (extent) inode is not the * base inode we will unmap it when we reinitialize the * search context which means we need to get a * reference to the page containing the mapped mft * record so we do not accidentally drop changes to the * mft record when it has not been marked dirty yet. */ if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino != old_ctx.base_ntfs_ino) { put_this_page = old_ctx.ntfs_ino->page; page_cache_get(put_this_page); } /* * Reinitialize the search context so we can lookup the * needed attribute extent. */ ntfs_attr_reinit_search_ctx(ctx); ctx_needs_reset = TRUE; } } if (ctx_needs_reset) { err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, CASE_SENSITIVE, vcn, NULL, 0, ctx); if (unlikely(err)) { if (err == -ENOENT) err = -EIO; goto err_out; } BUG_ON(!ctx->attr->non_resident); } a = ctx->attr; /* * Only decompress the mapping pairs if @vcn is inside it. Otherwise * we get into problems when we try to map an out of bounds vcn because * we then try to map the already mapped runlist fragment and * ntfs_mapping_pairs_decompress() fails. */ end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1; if (!a->data.non_resident.lowest_vcn && end_vcn == 1) end_vcn = sle64_to_cpu(a->data.non_resident.allocated_size) >> ni->vol->cluster_size_bits; if (unlikely(vcn >= end_vcn)) { err = -ENOENT; goto err_out; } rl = ntfs_mapping_pairs_decompress(ni->vol, a, ni->runlist.rl); if (IS_ERR(rl)) err = PTR_ERR(rl); else ni->runlist.rl = rl; err_out: if (ctx_is_temporary) { if (likely(ctx)) ntfs_attr_put_search_ctx(ctx); unmap_mft_record(base_ni); } else if (ctx_needs_reset) { /* * If there is no attribute list, restoring the search context * is acomplished simply by copying the saved context back over * the caller supplied context. If there is an attribute list, * things are more complicated as we need to deal with mapping * of mft records and resulting potential changes in pointers. */ if (NInoAttrList(base_ni)) { /* * If the currently mapped (extent) inode is not the * one we had before, we need to unmap it and map the * old one. */ if (ctx->ntfs_ino != old_ctx.ntfs_ino) { /* * If the currently mapped inode is not the * base inode, unmap it. */ if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino) { unmap_extent_mft_record(ctx->ntfs_ino); ctx->mrec = ctx->base_mrec; BUG_ON(!ctx->mrec); } /* * If the old mapped inode is not the base * inode, map it. */ if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino != old_ctx.base_ntfs_ino) { retry_map: ctx->mrec = map_mft_record( old_ctx.ntfs_ino); /* * Something bad has happened. If out * of memory retry till it succeeds. * Any other errors are fatal and we * return the error code in ctx->mrec. * Let the caller deal with it... We * just need to fudge things so the * caller can reinit and/or put the * search context safely. */ if (IS_ERR(ctx->mrec)) { if (PTR_ERR(ctx->mrec) == -ENOMEM) { schedule(); goto retry_map; } else old_ctx.ntfs_ino = old_ctx. base_ntfs_ino; } } } /* Update the changed pointers in the saved context. */ if (ctx->mrec != old_ctx.mrec) { if (!IS_ERR(ctx->mrec)) old_ctx.attr = (ATTR_RECORD*)( (u8*)ctx->mrec + ((u8*)old_ctx.attr - (u8*)old_ctx.mrec)); old_ctx.mrec = ctx->mrec; } } /* Restore the search context to the saved one. */ *ctx = old_ctx; /* * We drop the reference on the page we took earlier. In the * case that IS_ERR(ctx->mrec) is true this means we might lose * some changes to the mft record that had been made between * the last time it was marked dirty/written out and now. This * at this stage is not a problem as the mapping error is fatal * enough that the mft record cannot be written out anyway and * the caller is very likely to shutdown the whole inode * immediately and mark the volume dirty for chkdsk to pick up * the pieces anyway. */ if (put_this_page) page_cache_release(put_this_page); } return err; } /** * 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. There is one special error code * which is not an error as such. This is -ENOENT. It means that @vcn is out * of bounds of the runlist. * * Locking: - The runlist must be unlocked on entry and is unlocked on return. * - This function takes the runlist lock for writing and may modify * the runlist. */ int ntfs_map_runlist(ntfs_inode *ni, VCN vcn) { int err = 0; 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)) err = ntfs_map_runlist_nolock(ni, vcn, NULL); up_write(&ni->runlist.lock); return err; } /** * ntfs_attr_vcn_to_lcn_nolock - convert a vcn into a lcn given an ntfs inode * @ni: ntfs inode of the attribute whose runlist to search * @vcn: vcn to convert * @write_locked: true if the runlist is locked for writing * * Find the virtual cluster number @vcn in the runlist of the ntfs attribute * described by the ntfs inode @ni and return the corresponding logical cluster * number (lcn). * * If the @vcn is not mapped yet, the attempt is made to map the attribute * extent containing the @vcn and the vcn to lcn conversion is retried. * * If @write_locked is true the caller has locked the runlist for writing and * if false for reading. * * Since lcns must be >= 0, we use negative return codes with special meaning: * * Return code Meaning / Description * ========================================== * LCN_HOLE Hole / not allocated on disk. * LCN_ENOENT There is no such vcn in the runlist, i.e. @vcn is out of bounds. * LCN_ENOMEM Not enough memory to map runlist. * LCN_EIO Critical error (runlist/file is corrupt, i/o error, etc). * * Locking: - The runlist must be locked on entry and is left locked on return. * - If @write_locked is FALSE, i.e. the runlist is locked for reading, * the lock may be dropped inside the function so you cannot rely on * the runlist still being the same when this function returns. */ LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn, const BOOL write_locked) { LCN lcn; unsigned long flags; BOOL is_retry = FALSE; ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.", ni->mft_no, (unsigned long long)vcn, write_locked ? "write" : "read"); BUG_ON(!ni); BUG_ON(!NInoNonResident(ni)); BUG_ON(vcn < 0); if (!ni->runlist.rl) { read_lock_irqsave(&ni->size_lock, flags); if (!ni->allocated_size) { read_unlock_irqrestore(&ni->size_lock, flags); return LCN_ENOENT; } read_unlock_irqrestore(&ni->size_lock, flags); } retry_remap: /* Convert vcn to lcn. If that fails map the runlist and retry once. */ lcn = ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn); if (likely(lcn >= LCN_HOLE)) { ntfs_debug("Done, lcn 0x%llx.", (long long)lcn); return lcn; } if (lcn != LCN_RL_NOT_MAPPED) { if (lcn != LCN_ENOENT) lcn = LCN_EIO; } else if (!is_retry) { int err; if (!write_locked) { up_read(&ni->runlist.lock); down_write(&ni->runlist.lock); if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) != LCN_RL_NOT_MAPPED)) { up_write(&ni->runlist.lock); down_read(&ni->runlist.lock); goto retry_remap; } } err = ntfs_map_runlist_nolock(ni, vcn, NULL); if (!write_locked) { up_write(&ni->runlist.lock); down_read(&ni->runlist.lock); } if (likely(!err)) { is_retry = TRUE; goto retry_remap; } if (err == -ENOENT) lcn = LCN_ENOENT; else if (err == -ENOMEM) lcn = LCN_ENOMEM; else lcn = LCN_EIO; } if (lcn != LCN_ENOENT) ntfs_error(ni->vol->sb, "Failed with error code %lli.", (long long)lcn); return lcn; } /** * ntfs_attr_find_vcn_nolock - find a vcn in the runlist of an ntfs inode * @ni: ntfs inode describing the runlist to search * @vcn: vcn to find * @ctx: active attribute search context if present or NULL if not * * 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. * * If the @vcn is not mapped yet, the attempt is made to map the attribute * extent containing the @vcn and the vcn to lcn conversion is retried. * * If @ctx is specified, it is an active search context of @ni and its base mft * record. This is needed when ntfs_attr_find_vcn_nolock() encounters unmapped * runlist fragments and allows their mapping. If you do not have the mft * record mapped, you can specify @ctx as NULL and ntfs_attr_find_vcn_nolock() * will perform the necessary mapping and unmapping. * * Note, ntfs_attr_find_vcn_nolock() saves the state of @ctx on entry and * restores it before returning. Thus, @ctx will be left pointing to the same * attribute on return as on entry. However, the actual pointers in @ctx may * point to different memory locations on return, so you must remember to reset * any cached pointers from the @ctx, i.e. after the call to * ntfs_attr_find_vcn_nolock(), you will probably want to do: * m = ctx->mrec; * a = ctx->attr; * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that * you cache ctx->mrec in a variable @m of type MFT_RECORD *. * 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). * * WARNING: If @ctx is supplied, regardless of whether success or failure is * returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx * is no longer valid, i.e. you need to either call * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it. * In that case PTR_ERR(@ctx->mrec) will give you the error code for * why the mapping of the old inode failed. * * Locking: - The runlist described by @ni must be locked for writing on entry * and is locked on return. Note the runlist may be modified when * needed runlist fragments need to be mapped. * - If @ctx is NULL, the base mft record of @ni must not be mapped on * entry and it will be left unmapped on return. * - If @ctx is not NULL, the base mft record must be mapped on entry * and it will be left mapped on return. */ runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn, ntfs_attr_search_ctx *ctx) { unsigned long flags; runlist_element *rl; int err = 0; BOOL is_retry = FALSE; ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, with%s ctx.", ni->mft_no, (unsigned long long)vcn, ctx ? "" : "out"); BUG_ON(!ni); BUG_ON(!NInoNonResident(ni)); BUG_ON(vcn < 0); if (!ni->runlist.rl) { read_lock_irqsave(&ni->size_lock, flags); if (!ni->allocated_size) { read_unlock_irqrestore(&ni->size_lock, flags); return ERR_PTR(-ENOENT); } read_unlock_irqrestore(&ni->size_lock, flags); } retry_remap: rl = ni->runlist.rl; if (likely(rl && vcn >= rl[0].vcn)) { while (likely(rl->length)) { if (unlikely(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 (!err && !is_retry) { /* * If the search context is invalid we cannot map the unmapped * region. */ if (IS_ERR(ctx->mrec)) err = PTR_ERR(ctx->mrec); else { /* * The @vcn is in an unmapped region, map the runlist * and retry. */ err = ntfs_map_runlist_nolock(ni, vcn, ctx); if (likely(!err)) { is_retry = TRUE; goto retry_remap; } } if (err == -EINVAL) err = -EIO; } else if (!err) err = -EIO; if (err != -ENOENT) 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; if (!rl) { ntfs_error(sb, "Cannot read attribute list since runlist is " "missing."); goto err_out; } /* 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."); BUG_ON(IS_ERR(ctx->mrec)); 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);


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