/* * attrib.c - Attribute handling code. Part of the Linux-NTFS project. * * Copyright (c) 2000-2002 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 #include #include #include #include "attrib.h" #include "disk_io.h" #include "mft.h" #include "debug.h" #include "mst.h" #include "volume.h" #include "types.h" #include "layout.h" #include "inode.h" #include "runlist.h" uchar_t AT_UNNAMED[] = { const_cpu_to_le16('\0') }; /** * ntfs_get_attribute_value_length */ s64 ntfs_get_attribute_value_length(const ATTR_RECORD *a) { if (!a) { errno = EINVAL; return 0; } errno = 0; if (a->non_resident) return sle64_to_cpu(a->data_size); else return (s64)le32_to_cpu(a->value_length); errno = EINVAL; return 0; } /** * ntfs_get_attribute_value */ s64 ntfs_get_attribute_value(const ntfs_volume *vol, const MFT_RECORD *m, const ATTR_RECORD *a, u8 *b) { /* Sanity checks. */ if (!vol || !m || !a || !b) { errno = EINVAL; return 0; } /* Complex attribute? */ if (a->flags) { puts("Enountered non-zero attribute flags. Cannot handle this " "yet."); errno = ENOTSUP; return 0; } if (!a->non_resident) { /* Attribute is resident. */ /* Sanity check. */ if (le32_to_cpu(a->value_length) + le16_to_cpu(a->value_offset) > le32_to_cpu(a->length)) { return 0; } memcpy(b, (char*)a + le16_to_cpu(a->value_offset), le32_to_cpu(a->value_length)); errno = 0; return (s64)le32_to_cpu(a->value_length); } else { /* Attribute is not resident. */ runlist *rl; s64 total, r; int i; /* If no data, return 0. */ if (!(a->data_size)) { errno = 0; return 0; } /* * FIXME: What about attribute lists?!? (AIA) */ /* Decompress the mapping pairs array into a runlist. */ rl = ntfs_mapping_pairs_decompress(vol, a, NULL); if (!rl) { errno = EINVAL; return 0; } /* * FIXED: We were overflowing here in a nasty fashion when we * reach the last cluster in the runlist as the buffer will * only be big enough to hold data_size bytes while we are * reading in allocated_size bytes which is usually larger * than data_size, since the actual data is unlikely to have a * size equal to a multiple of the cluster size! */ /* Now load all clusters in the runlist into b. */ for (i = 0, total = 0; rl[i].length; i++) { if (!rl[i+1].length) { unsigned char *intbuf = NULL; /* * We have reached the last run so we were * going to overflow when executing the * ntfs_pread() which is BAAAAAAAD! * Temporary fix: * Allocate a new buffer with size: * rl[i].length << vol->cluster_size_bits, * do the read into our buffer, then * memcpy the correct amount of data into * the caller supplied buffer, free our * buffer, and continue. */ intbuf = malloc(rl[i].length << vol->cluster_size_bits); if (!intbuf) { int eo = errno; perror("Couldn't allocate memory for " "internal buffer.\n"); free(rl); errno = eo; return 0; } /* * FIXME: If compressed file: Only read if * lcn != -1. Otherwise, we are dealing with a * sparse run and we just memset the user buffer * to 0 for the length of the run, which should * be 16 (= compression unit size). * FIXME: Really only when file is compressed, * or can we have sparse runs in uncompressed * files as well? */ r = ntfs_pread(vol->fd, rl[i].lcn << vol->cluster_size_bits, rl[i].length << vol->cluster_size_bits, intbuf); if (r != rl[i].length << vol->cluster_size_bits) { #define ESTR "Error reading attribute value" if (r == -1) { int eo = errno; perror(ESTR); errno = eo; } else if (r < rl[i].length << vol->cluster_size_bits ) { fprintf(stderr, ESTR ": Ran " "out of input data.\n"); errno = EIO; } else { fprintf(stderr, ESTR ": " "unknown error\n"); errno = EIO; } #undef ESTR free(rl); return 0; } memcpy(b + total, intbuf, sle64_to_cpu(a->data_size) - total); free(intbuf); total = sle64_to_cpu(a->data_size); } else { /* * FIXME: If compressed file: Only read if * lcn != -1. Otherwise, we are dealing with a * sparse run and we just memset the user buffer * to 0 for the length of the run, which should * be 16 (= compression unit size). */ r = ntfs_pread(vol->fd, rl[i].lcn << vol->cluster_size_bits, rl[i].length << vol->cluster_size_bits, b + total); if (r != rl[i].length << vol->cluster_size_bits) { #define ESTR "Error reading attribute value" if (r == -1) { int eo = errno; perror(ESTR); errno = eo; } else if (r < rl[i].length << vol->cluster_size_bits ) { fprintf(stderr, ESTR ": Ran " "out of input data.\n"); errno = EIO; } else { fprintf(stderr, ESTR ": " "unknown error\n"); errno = EIO; } #undef ESTR return 0; } total += r; } } free(rl); return total; } errno = EINVAL; return 0; } /* Already cleaned up code below, but still look for FIXME:... */ /** * Internal: * * __ntfs_attr_init - primary initialization of an ntfs attribute structure * @na: ntfs attribute to initialize * @ni: ntfs inode with which to initialize the ntfs attribute * @type: attribute type * @name: attribute name in little endian Unicode or NULL * @name_len: length of attribute @name in Unicode characters (if @name given) * * Initialize the ntfs attribute @na with @ni, @type, @name, and @name_len. */ static __inline__ void __ntfs_attr_init(ntfs_attr *na, ntfs_inode *ni, const ATTR_TYPES type, uchar_t *name, const u32 name_len) { na->rl = NULL; na->ni = ni; na->type = type; if (name) { na->name = name; na->name_len = name_len; } else { na->name = AT_UNNAMED; na->name_len = 0; } } /** * ntfs_attr_init - initialize an ntfs_attr with data sizes and status * @na: * @non_resident: * @compressed: * @ecnrypted: * @sparse: * @allocated_size: * @data_size: * @initialized_size: * @compressed_size: * @compression_unit: * * Final initialization for an ntfs attribute. */ void ntfs_attr_init(ntfs_attr *na, const BOOL non_resident, const BOOL compressed, const BOOL encrypted, const BOOL sparse, const s64 allocated_size, const s64 data_size, const s64 initialized_size, const s64 compressed_size, const u8 compression_unit) { if (!NAttrInitialized(na)) { if (non_resident) NAttrSetNonResident(na); if (compressed) NAttrSetCompressed(na); if (encrypted) NAttrSetEncrypted(na); if (sparse) NAttrSetSparse(na); na->allocated_size = allocated_size; na->data_size = data_size; na->initialized_size = initialized_size; if (compressed || sparse) { ntfs_volume *vol = na->ni->vol; na->compressed_size = compressed_size; na->compression_block_clusters = 1 << compression_unit; na->compression_block_size = 1 << (compression_unit + vol->cluster_size_bits); na->compression_block_size_bits = ffs( na->compression_block_size) - 1; } NAttrSetInitialized(na); } } /** * ntfs_attr_open - open an ntfs attribute for access * @ni: open ntfs inode in which the ntfs attribute resides * @type: attribute type * @name: attribute name in little endian Unicode or NULL * @name_len: length of attribute @name in Unicode characters (if @name given) * * Allocate a new ntfs attribute structure, initialize it with @ni, @type, * @name, and @name_len, then return it. Return NULL on error with * errno set to the error code. * * If looking for an unnamed attribute set @name to NULL. @name_len is not used * at all in that case. */ ntfs_attr *ntfs_attr_open(ntfs_inode *ni, const ATTR_TYPES type, uchar_t *name, const u32 name_len) { ntfs_attr_search_ctx *ctx; ntfs_attr *na; ATTR_RECORD *a; int err; Dprintf("%s(): Entering for inode 0x%Lx, attr 0x%x.\n", __FUNCTION__, (unsigned long long)ni->mft_no, type); if (!ni || !ni->vol || !ni->mrec) { errno = EINVAL; return NULL; } na = calloc(sizeof(ntfs_attr), 1); if (!na) return NULL; __ntfs_attr_init(na, ni, type, name, name_len); ctx = ntfs_attr_get_search_ctx(ni, NULL); if (!ctx) { err = errno; goto err_out; } if (ntfs_attr_lookup(type, name, name_len, 0, 0, NULL, 0, ctx)) { err = errno; goto put_err_out; } a = ctx->attr; if (a->non_resident) { BOOL cs = a->flags & (ATTR_IS_COMPRESSED | ATTR_IS_SPARSE); ntfs_attr_init(na, TRUE, a->flags & ATTR_IS_COMPRESSED, a->flags & ATTR_IS_ENCRYPTED, a->flags & ATTR_IS_SPARSE, sle64_to_cpu(a->allocated_size), sle64_to_cpu(a->data_size), sle64_to_cpu(a->initialized_size), cs ? sle64_to_cpu(a->compressed_size) : 0, cs ? a->compression_unit : 0); } else { s64 l = le32_to_cpu(a->value_length); if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_ENCRYPTED | ATTR_IS_SPARSE)) { err = EIO; goto put_err_out; } ntfs_attr_init(na, FALSE, FALSE, FALSE, FALSE, l, l, l, 0, 0); } ntfs_attr_put_search_ctx(ctx); return na; put_err_out: ntfs_attr_put_search_ctx(ctx); err_out: errno = err; return NULL; } /** * ntfs_attr_close - free an ntfs attribute structure * @na: ntfs attribute structure to free * * Release all memory associated with the ntfs attribute @na and then release * @na itself. */ void ntfs_attr_close(ntfs_attr *na) { if (NAttrNonResident(na) && na->rl) free(na->rl); if (na->name != AT_UNNAMED) free(na->name); free(na); return; } /** * ntfs_attr_map_runlist - map (a part of) a runlist of an ntfs attribute * @na: ntfs attribute 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 an the ntfs attribute @na. * * Return 0 on success and -1 on error with errno set to the error code. */ int ntfs_attr_map_runlist(ntfs_attr *na, VCN vcn) { ntfs_attr_search_ctx *ctx; int err; Dprintf("%s(): Entering for inode 0x%Lx, attr 0x%x, vcn 0x%Lx.\n", __FUNCTION__, (unsigned long long)na->ni->mft_no, na->type, (long long)vcn); ctx = ntfs_attr_get_search_ctx(na->ni, NULL); if (!ctx) return -1; /* Find the attribute in the mft record. */ if (!ntfs_attr_lookup(na->type, na->name, na->name_len, CASE_SENSITIVE, vcn, NULL, 0, ctx)) { runlist_element *rl; /* Decode the runlist. */ rl = ntfs_mapping_pairs_decompress(na->ni->vol, ctx->attr, na->rl); if (rl) { na->rl = rl; ntfs_attr_put_search_ctx(ctx); return 0; } } err = errno; ntfs_attr_put_search_ctx(ctx); errno = err; return -1; } /** * ntfs_attr_vcn_to_lcn - convert a vcn into a lcn given an ntfs attribute * @na: ntfs attribute whose runlist to use for conversion * @vcn: vcn to convert * * Convert the virtual cluster number @vcn of an attribute into a logical * cluster number (lcn) of a device using the runlist @na->rl to map vcns to * their corresponding lcns. * * If the @vcn is not mapped yet, attempt to map the attribute extent * containing the @vcn and retry the vcn to lcn conversion. * * Since lcns must be >= 0, we use negative return values with special meaning: * * Return value Meaning / Description * ========================================== * -1 = LCN_HOLE Hole / not allocated on disk. * -3 = LCN_ENOENT There is no such vcn in the attribute. * -4 = LCN_EINVAL Input parameter error. * -5 = LCN_EIO Corrupt fs, disk i/o error, or not enough memory. */ LCN ntfs_attr_vcn_to_lcn(ntfs_attr *na, const VCN vcn) { LCN lcn; BOOL is_retry = FALSE; if (!na || !NAttrNonResident(na) || vcn < 0) return (LCN)LCN_EINVAL; retry: /* Convert vcn to lcn. If that fails map the runlist and retry once. */ lcn = ntfs_rl_vcn_to_lcn(na->rl, vcn); if (lcn >= 0) return lcn; if (!is_retry && !ntfs_attr_map_runlist(na, vcn)) { is_retry = TRUE; goto retry; } /* * If the attempt to map the runlist failed, or we are getting * LCN_RL_NOT_MAPPED despite having mapped the attribute extent * successfully, something is really badly wrong... */ if (!is_retry || lcn == (LCN)LCN_RL_NOT_MAPPED) return (LCN)LCN_EIO; /* lcn contains the appropriate error code. */ return lcn; } /** * ntfs_attr_find_vcn - find a vcn in the runlist of an ntfs attribute * @na: ntfs attribute whose runlist to search * @vcn: vcn to find * * Find the virtual cluster number @vcn in the runlist of the ntfs attribute * @na and return the the address of the runlist element containing the @vcn. * * 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. You need to update the runlist, the * attribute itself as well as write the modified mft record to disk. * * If there is an error return NULL with errno set to the error code. The * following error codes are defined: * EINVAL Input parameter error. * ENOENT There is no such vcn in the runlist. * ENOMEM Not enough memory. * EIO I/O error or corrupt metadata. */ runlist_element *ntfs_attr_find_vcn(ntfs_attr *na, const VCN vcn) { runlist_element *rl; BOOL is_retry = FALSE; if (!na || !NAttrNonResident(na) || vcn < 0) { errno = EINVAL; return NULL; } retry: rl = na->rl; if (!rl) goto map_rl; if (vcn < rl[0].vcn) goto map_rl; while (rl->length) { if (vcn < rl[1].vcn) { if (rl->lcn >= (LCN)LCN_HOLE) return rl; break; } rl++; } switch (rl->lcn) { case (LCN)LCN_RL_NOT_MAPPED: goto map_rl; case (LCN)LCN_ENOENT: errno = ENOENT; break; case (LCN)LCN_EINVAL: errno = EINVAL; break; default: errno = EIO; break; } return NULL; map_rl: /* The @vcn is in an unmapped region, map the runlist and retry. */ if (!is_retry && !ntfs_attr_map_runlist(na, vcn)) { is_retry = TRUE; goto retry; } /* * If we already retried or the mapping attempt failed something has * gone badly wrong. EINVAL and ENOENT coming from a failed mapping * attempt are equivalent to errors for us as they should not happen * in our code paths. */ if (is_retry || errno == EINVAL || errno == ENOENT) errno = EIO; return NULL; } /** * ntfs_attr_pread - read from an attribute specified by an ntfs_attr structure * @na: ntfs attribute to read from * @pos: byte position in the attribute to begin reading from * @count: number of bytes to read * @b: output data buffer * * This function will read @count bytes starting at offset @pos from the ntfs * attribute @na into the data buffer @b. * * On success, return the number of successfully read bytes. If this number is * lower than @count this means that the read reached end of file or thet an * error was encountered during the read so that the read is partial. 0 means * end of file or nothing was read (also return 0 when @count is 0). * * On error and nothing has been read, return -1 with errno set appropriately * to the return code of ntfs_pread(), or to EINVAL in case of invalid * arguments. */ s64 ntfs_attr_pread(ntfs_attr *na, const s64 pos, s64 count, void *b) { s64 br, to_read, ofs, total, total2; ntfs_volume *vol; runlist_element *rl; int f; Dprintf("%s(): Entering for inode 0x%Lx, attr 0x%x, pos 0x%Lx, " "count 0x%Lx.\n", __FUNCTION__, (unsigned long long)na->ni->mft_no, na->type, (long long)pos, (long long)count); if (!na || !na->ni || !na->ni->vol || !b || pos < 0 || count < 0) { errno = EINVAL; return -1; } vol = na->ni->vol; f = vol->fd; if (!f) { errno = EBADF; return -1; } /* * Encrypted attributes are not supported. We return access denied, * which is what Windows NT4 does, too. */ if (NAttrEncrypted(na)) { errno = EACCES; return -1; } /* If this is a compressed attribute it needs special treatment. */ if (NAttrCompressed(na)) { // TODO: Implement reading compressed attributes! (AIA) // return ntfs_attr_pread_compressed(ntfs_attr *na, // const s64 pos, s64 count, void *b); errno = ENOTSUP; return -1; } if (!count) return 0; /* Truncate reads beyond end of attribute. */ if (pos + count > na->data_size) { if (pos >= na->data_size) return 0; count = na->data_size - pos; } /* If it is a resident attribute, get the value from the mft record. */ if (!NAttrNonResident(na)) { ntfs_attr_search_ctx *ctx; char *val; ctx = ntfs_attr_get_search_ctx(na->ni, NULL); if (!ctx) return -1; if (ntfs_attr_lookup(na->type, na->name, na->name_len, 0, 0, NULL, 0, ctx)) { int eo; res_err_out: eo = errno; ntfs_attr_put_search_ctx(ctx); errno = eo; return -1; } val = (char*)ctx->attr + le16_to_cpu(ctx->attr->value_offset); if (val < (char*)ctx->attr || val + le32_to_cpu(ctx->attr->value_length) > (char*)ctx->mrec + vol->mft_record_size) { errno = EIO; goto res_err_out; } memcpy(b, val + pos, count); ntfs_attr_put_search_ctx(ctx); return count; } total = total2 = 0; /* Zero out reads beyond initialized size. */ if (pos + count > na->initialized_size) { if (pos >= na->initialized_size) { memset(b, 0, count); return count; } total2 = pos + count - na->initialized_size; count -= total2; memset((u8*)b + count, 0, total2); } /* Find the runlist element containing the vcn. */ rl = ntfs_attr_find_vcn(na, pos >> vol->cluster_size_bits); if (!rl) { /* * If the vcn is not present it is an out of bounds read. * However, we already truncated the read to the data_size, * so getting this here is an error. */ if (errno == ENOENT) errno = EIO; return -1; } /* * Gather the requested data into the linear destination buffer. Note, * a partial final vcn is taken care of by the @count capping of read * length. */ ofs = pos - (rl->vcn << vol->cluster_size_bits); for (; count; rl++, ofs = 0) { if (!rl->length) goto rl_err_out; if (rl->lcn < (LCN)0) { if (rl->lcn != (LCN)LCN_HOLE) goto rl_err_out; /* It is a hole, just zero the matching @b range. */ to_read = min(count, (rl->length << vol->cluster_size_bits) - ofs); memset(b, 0, to_read); /* Update progress counters. */ total += to_read; count -= to_read; (u8*)b += to_read; continue; } /* It is a real lcn, read it into @dst. */ to_read = min(count, (rl->length << vol->cluster_size_bits) - ofs); retry: Dprintf("%s(): Reading 0x%Lx bytes from vcn 0x%Lx, lcn 0x%Lx, " "ofs 0x%Lx.\n", __FUNCTION__, to_read, rl->vcn, rl->lcn, ofs); br = ntfs_pread(f, (rl->lcn << vol->cluster_size_bits) + ofs, to_read, b); /* If everything ok, update progress counters and continue. */ if (br > 0) { total += br; count -= br; (u8*)b += br; continue; } /* If the syscall was interrupted, try again. */ if (br == (s64)-1 && errno == EINTR) goto retry; if (total) return total; if (!br) errno = EIO; return -1; } /* Finally, return the number of bytes read. */ return total + total2; rl_err_out: if (total) return total; errno = EIO; return -1; } /** * ntfs_attr_pwrite - positioned write to an ntfs attribute * @na: ntfs attribute to write to * @pos: position in the attribute to write to * @count: number of bytes to write * @b: data buffer to write to disk * * This function will write @count bytes from data buffer @b to ntfs attribute * @na at position @pos. * * On success, return the number of successfully written bytes. If this number * is lower than @count this means that an error was encountered during the * write so that the write is partial. 0 means nothing was written (also return * 0 when @count is 0). * * On error and nothing has been written, return -1 with errno set * appropriately to the return code of ntfs_pwrite(), or to EINVAL in case of * invalid arguments. * * NOTE: Currently changes in length of the attribute @na are not implemented. * Thus if such a change is requested we return -1 with errno set to ENOTSUP. */ s64 ntfs_attr_pwrite(ntfs_attr *na, const s64 pos, s64 count, void *b) { s64 written, to_write, ofs, total, old_initialized_size; ntfs_volume *vol; ntfs_attr_search_ctx *ctx = NULL; runlist_element *rl; int f, eo; struct { unsigned int initialized_size : 1; } need_to_undo = { 0 }; Dprintf("%s(): Entering for inode 0x%Lx, attr 0x%x, pos 0x%Lx, " "count 0x%Lx.\n", __FUNCTION__, na->ni->mft_no, na->type, (long long)pos, (long long)count); if (!na || !na->ni || !na->ni->vol || !b || pos < 0 || count < 0) { errno = EINVAL; return -1; } vol = na->ni->vol; f = vol->fd; if (!f) { errno = EBADF; return -1; } /* * Encrypted attributes are not supported. We return access denied, * which is what Windows NT4 does, too. */ if (NAttrEncrypted(na)) { errno = EACCES; return -1; } /* If this is a compressed attribute it needs special treatment. */ if (NAttrCompressed(na)) { // TODO: Implement writing compressed attributes! (AIA) // return ntfs_attr_pwrite_compressed(ntfs_attr *na, // const s64 pos, s64 count, void *b); errno = ENOTSUP; return -1; } if (!count) return 0; /* If the write reaches beyond the end, extend the attribute. */ if (pos + count > na->data_size) { // TODO: Need to extend the attribute. For now, just do a // partial write or abort if completely out of bounds. (AIA) if (pos >= na->data_size) { errno = ENOTSUP; return -1; } count = na->data_size - pos; } old_initialized_size = na->initialized_size; /* If it is a resident attribute, write the data to the mft record. */ if (!NAttrNonResident(na)) { char *val; ctx = ntfs_attr_get_search_ctx(na->ni, NULL); if (!ctx) goto err_out; if (ntfs_attr_lookup(na->type, na->name, na->name_len, 0, 0, NULL, 0, ctx)) goto err_out; val = (char*)ctx->attr + le16_to_cpu(ctx->attr->value_offset); if (val < (char*)ctx->attr || val + le32_to_cpu(ctx->attr->value_length) > (char*)ctx->mrec + vol->mft_record_size) { errno = EIO; goto err_out; } memcpy(val + pos, b, count); if (ntfs_mft_record_write(vol, ctx->ntfs_ino->mft_no, ctx->mrec)) { /* * NOTE: We are in a bad state at this moment. We have * dirtied the mft record but we failed to commit it to * disk. Since we have read the mft record ok before, * it is unlikely to fail writing it, so is ok to just * return error here... (AIA) */ goto err_out; } ntfs_attr_put_search_ctx(ctx); return count; } total = 0; /* Find the runlist element containing the vcn. */ rl = ntfs_attr_find_vcn(na, pos >> vol->cluster_size_bits); if (!rl) { /* * If the vcn is not present it is an out of bounds write. * However, we already extended the size of the attribute, * so getting this here must be an error of some kind. */ if (errno == ENOENT) errno = EIO; goto err_out; } /* Handle writes beyond initialized_size. */ if (pos + count > na->initialized_size) { /* Set initialized_size to @pos + @count. */ ctx = ntfs_attr_get_search_ctx(na->ni, NULL); if (!ctx) goto err_out; if (ntfs_attr_lookup(na->type, na->name, na->name_len, 0, 0, NULL, 0, ctx)) goto err_out; /* If write starts beyond initialized_size, zero the gap. */ if (pos > na->initialized_size) { // TODO: Need to write zeroes in the region from // na->initialized_size to @pos, then update the // initialized size to equal @pos. If any sparse runs // are encountered while filling the gap, need to // honour them, i.e. do not instantiate them. Then can // continue as if pos <= na->initialized_size, i.e. can // just fall through and continue. (AIA) errno = ENOTSUP; goto err_out; } ctx->attr->initialized_size = scpu_to_le64(pos + count); if (ntfs_mft_record_write(vol, ctx->ntfs_ino->mft_no, ctx->mrec)) { /* * Undo the change in the in-memory copy and send it * back for writing. */ ctx->attr->initialized_size = scpu_to_le64(old_initialized_size); ntfs_mft_record_write(vol, ctx->ntfs_ino->mft_no, ctx->mrec); goto err_out; } na->initialized_size = pos + count; ntfs_attr_put_search_ctx(ctx); ctx = NULL; /* * NOTE: At this point the initialized_size in the mft record * has been updated BUT there is random data on disk thus if * we decide to abort, we MUST change the initialized_size * again. */ need_to_undo.initialized_size = 1; } /* * Scatter the data from the linear data buffer to the volume. Note, a * partial final vcn is taken care of by the @count capping of write * length. */ ofs = pos - (rl->vcn << vol->cluster_size_bits); for (; count; rl++, ofs = 0) { if (!rl->length) { errno = EIO; goto rl_err_out; } if (rl->lcn < (LCN)0) { s64 t; int cnt; if (rl->lcn != (LCN)LCN_HOLE) { errno = EIO; goto rl_err_out; } /* * It is a hole. Check if the data buffer is zero in * this region and if not instantiate the hole. */ to_write = min(count, (rl->length << vol->cluster_size_bits) - ofs); written = to_write / sizeof(unsigned long); eo = 0; for (t = 0; t < written; t++) { if (((unsigned long*)b)[t]) { eo = 1; break; } } cnt = to_write & (sizeof(unsigned long) - 1); if (cnt && !eo) { int i; u8 *b2; b2 = (u8*)b + (to_write & ~(sizeof(unsigned long) - 1)); for (i = 0; i < cnt; i++) { if (b2[i]) { eo = 1; break; } } } if (eo) { // TODO: Need to instantiate the hole. Then get // the runlist element again checking if it is // ok and fall through to do the writing. (AIA) errno = ENOTSUP; goto rl_err_out; } /* * The buffer region is zero, update progress counters * and proceed with next run. */ total += to_write; count -= to_write; (u8*)b += to_write; continue; } /* It is a real lcn, write it to the volume. */ to_write = min(count, (rl->length << vol->cluster_size_bits) - ofs); retry: Dprintf("%s(): Writing 0x%Lx bytes to vcn 0x%Lx, lcn 0x%Lx, " "ofs 0x%Lx.\n", __FUNCTION__, to_write, rl->vcn, rl->lcn, ofs); written = ntfs_pwrite(f, (rl->lcn << vol->cluster_size_bits) + ofs, to_write, b); /* If everything ok, update progress counters and continue. */ if (written > 0) { total += written; count -= written; (u8*)b += written; continue; } /* If the syscall was interrupted, try again. */ if (written == (s64)-1 && errno == EINTR) goto retry; if (!written) errno = EIO; goto rl_err_out; } done: if (ctx) ntfs_attr_put_search_ctx(ctx); /* Finally, return the number of bytes written. */ return total; rl_err_out: eo = errno; if (total) { if (need_to_undo.initialized_size) { if (pos + total > na->initialized_size) goto done; // TODO: Need to try to change initialized_size. If it // succeeds goto done, otherwise goto err_out. (AIA) errno = ENOTSUP; goto err_out; } goto done; } errno = eo; err_out: eo = errno; if (need_to_undo.initialized_size) { int err; err = 0; if (!ctx) { ctx = ntfs_attr_get_search_ctx(na->ni, NULL); if (!ctx) err = 1; } else ntfs_attr_reinit_search_ctx(ctx); if (!err) { err = ntfs_attr_lookup(na->type, na->name, na->name_len, 0, 0, NULL, 0, ctx); if (!err) { na->initialized_size = old_initialized_size; ctx->attr->initialized_size = scpu_to_le64( old_initialized_size); err = ntfs_mft_record_write(vol, ctx->ntfs_ino->mft_no, ctx->mrec); } } if (err) { Dputs("Eeek! Failed to recover from error. Leaving " "metadata in inconsistent state! Run " "chkdsk!"); // FIXME: At this stage could try to recover by filling // old_initialized_size -> new_initialized_size with // data or at least zeroes. (AIA) } } if (ctx) ntfs_attr_put_search_ctx(ctx); errno = eo; return -1; } /** * ntfs_attr_mst_pread - multi sector transfer protected ntfs attribute read * @na: multi sector transfer protected ntfs attribute to read from * @pos: byte position in the attribute to begin reading from * @bk_cnt: number of mst protected blocks to read * @bk_size: size of each mst protected block in bytes * @b: output data buffer * * This function will read @bk_cnt blocks of size @bk_size bytes each starting * at offset @pos from the ntfs attribute @na into the data buffer @b. * * On success, the multi sector transfer fixups are applied and the number of * read blocks is returned. If this number is lower than @bk_cnt this means * that the read has either reached end of attribute or that an error was * encountered during the read so that the read is partial. 0 means end of * attribute or nothing to read (also return 0 when @bk_cnt or @bk_size are 0). * * On error and nothing has been read, return -1 with errno set appropriately * to the return code of ntfs_attr_pread() or to EINVAL in case of invalid * arguments. * * NOTE: If an incomplete multi sector transfer is detected the magic is * changed to BAAD but no error is returned, i.e. it is possible that any of * the returned blocks have multi sector transfer errors. This should be * detected by the caller by checking each block with is_baad_recordp(&block). * The reasoning is that we want to fixup as many blocks as possible and we * want to return even bad ones to the caller so, e.g. in case of ntfsck, the * errors can be repaired. */ s64 ntfs_attr_mst_pread(ntfs_attr *na, const s64 pos, const s64 bk_cnt, const u32 bk_size, void *b) { s64 br; u8 *end; Dprintf("%s(): Entering for inode 0x%Lx, attr type 0x%x, pos 0x%Lx.\n", __FUNCTION__, (unsigned long long)na->ni->mft_no, na->type, (long long)pos); if (bk_cnt < 0 || bk_size % NTFS_SECTOR_SIZE) { errno = EINVAL; return -1; } br = ntfs_attr_pread(na, pos, bk_cnt * bk_size, b); if (br <= 0) return br; br /= bk_size; for (end = (u8*)b + br * bk_size; (u8*)b < end; (u8*)b += bk_size) ntfs_mst_post_read_fixup((NTFS_RECORD*)b, bk_size); /* Finally, return the number of blocks read. */ return br; } /** * ntfs_attr_mst_pwrite - multi sector transfer protected ntfs attribute write * @na: multi sector transfer protected ntfs attribute to write to * @pos: position in the attribute to write to * @bk_cnt: number of mst protected blocks to write * @bk_size: size of each mst protected block in bytes * @b: data buffer to write to disk * * This function will write @bk_cnt blocks of size @bk_size bytes each from * data buffer @b to multi sector transfer (mst) protected ntfs attribute @na * at position @pos. * * On success, return the number of successfully written blocks. If this number * is lower than @bk_cnt this means that an error was encountered during the * write so that the write is partial. 0 means nothing was written (also * return 0 when @bk_cnt or @bk_size are 0). * * On error and nothing has been written, return -1 with errno set * appropriately to the return code of ntfs_attr_pwrite(), or to EINVAL in case * of invalid arguments. * * NOTE: We mst protect the data, write it, then mst deprotect it using a quick * deprotect algorithm (no checking). This saves us from making a copy before * the write and at the same time causes the usn to be incremented in the * buffer. This conceptually fits in better with the idea that cached data is * always deprotected and protection is performed when the data is actually * going to hit the disk and the cache is immediately deprotected again * simulating an mst read on the written data. This way cache coherency is * achieved. */ s64 ntfs_attr_mst_pwrite(ntfs_attr *na, const s64 pos, s64 bk_cnt, const u32 bk_size, void *b) { s64 written, i; Dprintf("%s(): Entering for inode 0x%Lx, attr type 0x%x, pos 0x%Lx.\n", __FUNCTION__, (unsigned long long)na->ni->mft_no, na->type, (long long)pos); if (bk_cnt < 0 || bk_size % NTFS_SECTOR_SIZE) { errno = EINVAL; return -1; } if (!bk_cnt) return 0; /* Prepare data for writing. */ for (i = 0; i < bk_cnt; ++i) { int err; err = ntfs_mst_pre_write_fixup((NTFS_RECORD*) ((u8*)b + i * bk_size), bk_size); if (err < 0) { /* Abort write at this position. */ if (!i) return err; bk_cnt = i; break; } } /* Write the prepared data. */ written = ntfs_attr_pwrite(na, pos, bk_cnt * bk_size, b); /* Quickly deprotect the data again. */ for (i = 0; i < bk_cnt; ++i) ntfs_mst_post_write_fixup((NTFS_RECORD*)((u8*)b + i * bk_size)); if (written <= 0) return written; /* Finally, return the number of complete blocks written. */ return written / bk_size; } /** * Internal: * * 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 shouldn't need to call this function directly. Use lookup_attr() 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 found, ntfs_attr_find() * returns 0 and @ctx->attr will point to the found attribute. If not found, * ntfs_attr_find() returns -1, with errno set to the error code and @ctx->attr * is undefined (i.e. 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 @type is zero (i.e. AT_UNUSED), return the first found attribute, i.e. * one can enumerate all attributes by setting @type to zero and then calling * ntfs_attr_find() repeatedly until it returns -1 with errno set to ENOENT to * indicate that there are no more entries. During the enumeration, each * successful call of ntfs_attr_find() will return the next attribute in the * mft record @ctx->mrec. * * If @type is AT_END, seek to the end and return -1 with errno set to ENOENT. * AT_END is not a valid attribute, its length is zero for example, thus it is * safer to return error instead of success in this case. This also allows us * to interoperate cleanly with ntfs_external_attr_find(). * * If @name is AT_UNNAMED search for an unnamed attribute. If @name is present * but not AT_UNNAMED search for a named attribute matching @name. Otherwise, * match both named and unnamed attributes. * * 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 don't * 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_TYPES type, const uchar_t *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; uchar_t *upcase; u32 upcase_len; if (!ctx || !ctx->mrec || !ctx->attr) { errno = EINVAL; return -1; } if (ic == IGNORE_CASE) { vol = ctx->ntfs_ino->vol; upcase = vol->upcase; upcase_len = vol->upcase_len; } else { vol = NULL; upcase = NULL; upcase_len = 0; } /* * 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*)((char*)ctx->attr + le32_to_cpu(ctx->attr->length)); for (;; a = (ATTR_RECORD*)((char*)a + le32_to_cpu(a->length))) { if (p2n(a) < p2n(ctx->mrec) || (char*)a > (char*)ctx->mrec + le32_to_cpu(ctx->mrec->bytes_allocated)) break; ctx->attr = a; /* We catch $END with this more general check, too... */ if ((type && (le32_to_cpu(a->type) > le32_to_cpu(type))) || (a->type == AT_END)) { errno = ENOENT; return -1; } if (!a->length) break; /* If this is an enumeration return this attribute. */ if (!type) return 0; if (a->type != type) continue; /* * If @name is AT_UNNAMED we want an unnamed attribute. * If @name is present, compare the two names. * Otherwise, match any attribute. */ if (name == AT_UNNAMED) { /* The search failed if the found attribute is named. */ if (a->name_length) { errno = ENOENT; return -1; } } else if (name && !ntfs_names_are_equal(name, name_len, (uchar_t*)((char*)a + le16_to_cpu(a->name_offset)), a->name_length, ic, upcase, upcase_len)) { register int rc; rc = ntfs_names_collate(name, name_len, (uchar_t*)((char*)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) { errno = ENOENT; return -1; } /* If the strings are not equal, continue search. */ if (rc) continue; rc = ntfs_names_collate(name, name_len, (uchar_t*)((char*)a + le16_to_cpu(a->name_offset)), a->name_length, 1, CASE_SENSITIVE, upcase, upcase_len); if (rc == -1) { errno = ENOENT; return -1; } 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, (char*)a +le16_to_cpu(a->value_offset), min(val_len, le32_to_cpu(a->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->value_length); if (val_len == avl) return 0; if (val_len < avl) { errno = ENOENT; return -1; } } else if (rc < 0) { errno = ENOENT; return -1; } } } Dputs("ntfs_attr_find(): File is corrupt. Run chkdsk."); errno = EIO; return -1; } /** * Internal: * * 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 shouldn't 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 for read * if the attribute is in a different mft record/inode, find the attribute in * there and return it. * * If @type is zero (i.e. AT_UNUSED), return the first found attribute, i.e. * one can enumerate all attributes by setting @type to zero and then calling * ntfs_external_attr_find() repeatedly until it returns -1 with errno set to * ENOENT to indicate that there are no more entries. During the enumeration, * each successful call of ntfs_external_attr_find() will return the next * attribute described by the attribute list of the base mft record described * by the search context @ctx. * * If @type is AT_END, seek to the end and return -1 with errno set to ENOENT. * AT_END is not a valid attribute, its length is zero for example, thus it is * safer to return error instead of success in this case. * * If @name is AT_UNNAMED search for an unnamed attribute. If @name is present * but not AT_UNNAMED search for a named attribute matching @name. Otherwise, * match both named and unnamed attributes. * * On first search @ctx->ntfs_ino must be the inode of 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 extent inodes, etc). * * Return 0 if the search was successful and -1 if not, with errno set to the * error code. * * On success, @ctx->attr is the found attribute and it is in mft record * @ctx->mrec. * * On error, @ctx->attr is the attribute which collates just after the attribute * being searched for in the base ntfs inode, i.e. if one wants to add the * attribute to the mft record this is the correct place to insert it into, * and if there is not enough space, the attribute should be placed in an * extent mft record. @ctx->al_entry points to the position within * @ctx->base_ntfs_ino->attr_list at which the new attribute's attribute list * entry should be inserted. * * The following error codes are defined: * ENOENT Attribute not found, not an error as such. * EINVAL Invalid arguments. * EIO I/O error or corrupt data structures found. * ENOMEM Not enough memory to allocate necessary buffers. */ static int ntfs_external_attr_find(ATTR_TYPES type, const uchar_t *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; char *al_start, *al_end; ATTR_RECORD *a; uchar_t *al_name; u32 al_name_len; ni = ctx->ntfs_ino; base_ni = ctx->base_ntfs_ino; Dprintf("Entering for inode %Lu, attribute type 0x%x.\n", (unsigned long long)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 (type == AT_END) goto not_found; if (ni == base_ni) ctx->base_attr = ctx->attr; 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*)((char*)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 || (char*)al_entry > al_end) break; /* Inode is corrupt. */ ctx->al_entry = al_entry; /* Catch the end of the attribute list. */ if ((char*)al_entry == al_end) goto not_found; if (!al_entry->length) break; if ((char*)al_entry + 6 > al_end || (char*)al_entry + le16_to_cpu(al_entry->length) > al_end) break; next_al_entry = (ATTR_LIST_ENTRY*)((char*)al_entry + le16_to_cpu(al_entry->length)); if (type) { if (le32_to_cpu(al_entry->type) > le32_to_cpu(type)) goto not_found; if (type != al_entry->type) continue; } al_name_len = al_entry->name_length; al_name = (uchar_t*)((char*)al_entry + al_entry->name_offset); /* * If !@type we want the attribute represented by this * attribute list entry. */ if (!type) goto is_enumeration; /* * If @name is AT_UNNAMED we want an unnamed attribute. * If @name is present, compare the two names. * Otherwise, match any attribute. */ if (name == AT_UNNAMED) { if (al_name_len) goto not_found; } else if (name && !ntfs_names_are_equal(al_name, al_name_len, name, name_len, ic, vol->upcase, vol->upcase_len)) { register int rc; rc = ntfs_names_collate(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_names_collate(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 && (char*)next_al_entry >= al_start && (char*)next_al_entry + 6 < al_end && (char*)next_al_entry + le16_to_cpu( next_al_entry->length) <= al_end && sle64_to_cpu(next_al_entry->lowest_vcn) <= sle64_to_cpu(lowest_vcn) && next_al_entry->type == al_entry->type && next_al_entry->name_length == al_name_len && ntfs_names_are_equal((uchar_t*)((char*) 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; is_enumeration: if (MREF_LE(al_entry->mft_reference) == ni->mft_no) { if (MSEQNO_LE(al_entry->mft_reference) != le16_to_cpu( ni->mrec->sequence_number)) { Dputs("Found stale mft reference in attribute " "list!"); break; } } else { /* Mft references do not match. */ /* If there is a mapped extent inode unmap it first. */ if (ni != base_ni) ntfs_inode_close(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. */ ni = ntfs_extent_inode_open(base_ni, al_entry->mft_reference); if (!ni) { Dperror("Failed to map extent inode"); break; } ctx->ntfs_ino = ni; ctx->mrec = ni->mrec; } ctx->attr = (ATTR_RECORD*)((char*)ctx->mrec + le16_to_cpu(ctx->mrec->attrs_offset)); } /* * ctx->ntfs_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 ((char*)a < (char*)ctx->mrec || (char*)a > (char*)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/is 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_names_are_equal((uchar_t*)((char*)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! Also, if !@type, it is an enumeration, so we * want the current attribute. */ if (!type || !val || (!a->non_resident && le32_to_cpu(a->value_length) == val_len && !memcmp((char*)a + le16_to_cpu(a->value_offset), val, val_len))) { return 0; } do_next_attr: /* Proceed to the next attribute in the current mft record. */ a = (ATTR_RECORD*)((char*)a + le32_to_cpu(a->length)); goto do_next_attr_loop; } if (ni != base_ni) { if (ni) ntfs_inode_close(ni); ctx->ntfs_ino = base_ni; ctx->mrec = ctx->base_mrec; ctx->attr = ctx->base_attr; } Dputs("Inode is corrupt."); errno = EIO; return -1; not_found: /* * Seek to the end of the base mft record, i.e. when we return false, * ctx->mrec and ctx->attr indicate where the attribute should be * inserted into the attribute record. * And of course ctx->al_entry points to the end of the attribute * list inside ctx->base_ntfs_ino->attr_list. * * FIXME: Do we really want to do this here? Think about it... (AIA) */ ntfs_attr_reinit_search_ctx(ctx); /* * If we were enumerating and reached the end, we can't just use !@type * because that would return the first attribute instead of the last * one. Thus we just change @type to AT_END which causes * ntfs_attr_find() to seek to the end. We also do the same when an * attribute extent was searched for (i.e. lowest_vcn != 0), as we * otherwise rewind the search back to the first extent and we get * that extent returned twice during a search for all extents. */ if (!type || lowest_vcn) type = AT_END; return ntfs_attr_find(type, name, name_len, ic, val, val_len, ctx); } /** * 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. * * If @type is zero (i.e. AT_UNUSED), return the first found attribute, i.e. * one can enumerate all attributes by setting @type to zero and then calling * ntfs_attr_lookup() repeatedly until it returns -1 with errno set to ENOENT * to indicate that there are no more entries. During the enumeration, each * successful call of ntfs_attr_lookup() will return the next attribute, with * the current attribute being described by the search context @ctx. * * If @type is AT_END, seek to the end of the attribute and return -1 with * errno set to ENOENT. AT_END is not a valid attribute, its length is zero for * example, thus it is safer to return error instead of success in this case. * It should never ne needed to do this, but we implement the functionality * because it allows for simpler code inside ntfs_external_attr_find(). * * If @name is AT_UNNAMED search for an unnamed attribute. If @name is present * but not AT_UNNAMED search for a named attribute matching @name. Otherwise, * match both named and unnamed attributes. * * After finishing with the attribute/mft record you need to call * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any * mapped extent inodes, etc). * * Return 0 if the search was successful and -1 if not, with errno set to the * error code. * * On success, @ctx->attr is the found attribute and it is in mft record * @ctx->mrec. * * On error, @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. @ctx->al_entry points to * the position within @ctx->base_ntfs_ino->attr_list at which the new * attribute's attribute list entry should be inserted. * * The following error codes are defined: * ENOENT Attribute not found, not an error as such. * EINVAL Invalid arguments. * EIO I/O error or corrupt data structures found. * ENOMEM Not enough memory to allocate necessary buffers. */ int ntfs_attr_lookup(const ATTR_TYPES type, const uchar_t *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; if (!ctx || !ctx->mrec || !ctx->attr) { errno = EINVAL; return -1; } if (ctx->base_ntfs_ino) base_ni = ctx->base_ntfs_ino; else base_ni = ctx->ntfs_ino; if (!base_ni || !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); } /** * Internal: * * 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) { if (ni && !mrec) mrec = ni->mrec; ctx->mrec = mrec; /* Sanity checks are performed elsewhere. */ ctx->attr = (ATTR_RECORD*)((char*)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. * * 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 (!ctx->base_ntfs_ino) { /* No attribute list. */ ctx->is_first = TRUE; /* Sanity checks are performed elsewhere. */ ctx->attr = (ATTR_RECORD*)((char*)ctx->mrec + le16_to_cpu(ctx->mrec->attrs_offset)); return; } /* Attribute list. */ 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 * @ctx: address of pointer in which to return the new 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 on error with errno set to ENOMEM. * * @ni can be NULL if the search context is only going to be used for searching * for the attribute list attribute and for searches ignoring the contents of * the attribute list attribute. * * If @ni is specified, @mrec can be NULL, in which case the mft record is * taken from @ni. * * If both @ni and @mrec are specified, the mft record is taken from @mrec and * the value of @ni->mrec is ignored. */ ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec) { ntfs_attr_search_ctx *ctx = malloc(sizeof(ntfs_attr_search_ctx)); 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. */ void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx) { free(ctx); return; } /** * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number * @n: number for which to get the number of bytes for * * Return the number of bytes required to store @n unambiguously as * a signed number. * * This is used in the context of the mapping pairs array to determine how * many bytes will be needed in the array to store a given logical cluster * number (lcn) or a specific run length. * * Return the number of bytes written. This function cannot fail. */ __inline__ int ntfs_get_nr_significant_bytes(const s64 n) { s64 l = n; int i; s8 j; i = 0; do { l >>= 8; i++; } while (l != 0LL && l != -1LL); j = (n >> 8 * (i - 1)) & 0xff; /* If the sign bit is wrong, we need an extra byte. */ if ((n < 0LL && j >= 0) || (n > 0LL && j < 0)) i++; return i; } /** * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array * @vol: ntfs volume (needed for the ntfs version) * @rl: runlist for which to determine the size of the mapping pairs * * Walk the runlist @rl and calculate the size in bytes of the mapping pairs * array corresponding to the runlist @rl. This for example allows us to * allocate a buffer of the right size when building the mapping pairs array. * * Return the calculated size in bytes on success. If @rl is NULL return 0. * On error, return -1 with errno set to the error code. The following error * codes are defined: * EINVAL - Run list contains unmapped elements. Make sure to only pass * fully mapped runlists to this function. * EIO - The runlist is corrupt. */ int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, const runlist_element *rl) { LCN prev_lcn; int i, rls; if (!rl) return 0; /* Always need the termining zero byte. */ rls = 1; for (prev_lcn = i = 0; rl[i].length; prev_lcn = rl[++i].lcn) { if (rl[i].length < 0 || rl[i].lcn < LCN_HOLE) goto err_out; /* Header byte + length. */ rls += 1 + ntfs_get_nr_significant_bytes(rl[i].length); /* * If the logical cluster number (lcn) denotes a hole and we * are on NTFS 3.0+, we don't store it at all, i.e. we need * zero space. On earlier NTFS versions we just store the lcn. */ if (rl[i].lcn == LCN_HOLE && vol->major_ver >= 3) continue; /* Change in lcn. */ rls += ntfs_get_nr_significant_bytes(rl[i].lcn - prev_lcn); } return rls; err_out: if (rl[i].lcn == LCN_RL_NOT_MAPPED) errno = EINVAL; else errno = EIO; return -1; } /** * ntfs_write_significant_bytes - write the significant bytes of a number * @dst: destination buffer to write to * @dst_max: pointer to last byte of destination buffer for bounds checking * @n: number whose significant bytes to write * * Store in @dst, the minimum bytes of the number @n which are required to * identify @n unambiguously as a signed number, taking care not to exceed * @dest_max, the maximum position within @dst to which we are allowed to * write. * * This is used when building the mapping pairs array of a runlist to compress * a given logical cluster number (lcn) or a specific run length to the minumum * size possible. * * Return the number of bytes written on success. On error, i.e. the * destination buffer @dst is too small, return -1 with errno set ENOSPC. */ __inline__ int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max, const s64 n) { s64 l = n; int i; s8 j; i = 0; do { if (dst > dst_max) goto err_out; *dst++ = l & 0xffLL; l >>= 8; i++; } while (l != 0LL && l != -1LL); j = (n >> 8 * (i - 1)) & 0xff; /* If the sign bit is wrong, we need an extra byte. */ if (n < 0LL && j >= 0) { if (dst > dst_max) goto err_out; i++; *dst = (s8)-1; } else if (n > 0LL && j < 0) { if (dst > dst_max) goto err_out; i++; *dst = (s8)0; } return i; err_out: errno = ENOSPC; return -1; }