// SPDX-License-Identifier: GPL-2.0+ /* * fat_write.c * * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "fat.c" static dir_entry *find_directory_entry(fat_itr *itr, char *filename); static int new_dir_table(fat_itr *itr); /* Characters that may only be used in long file names */ static const char LONG_ONLY_CHARS[] = "+,;=[]"; /* Combined size of the name and ext fields in the directory entry */ #define SHORT_NAME_SIZE 11 /** * str2fat() - convert string to valid FAT name characters * * Stop when reaching end of @src or a period. * Ignore spaces. * Replace characters that may only be used in long names by underscores. * Convert lower case characters to upper case. * * To avoid assumptions about the code page we do not use characters * above 0x7f for the short name. * * @dest: destination buffer * @src: source buffer * @length: size of destination buffer * Return: number of bytes in destination buffer */ static int str2fat(char *dest, char *src, int length) { int i; for (i = 0; i < length; ++src) { char c = *src; if (!c || c == '.') break; if (c == ' ') continue; if (strchr(LONG_ONLY_CHARS, c) || c > 0x7f) c = '_'; else if (c >= 'a' && c <= 'z') c &= 0xdf; dest[i] = c; ++i; } return i; } /** * fat_move_to_cluster() - position to first directory entry in cluster * * @itr: directory iterator * @cluster cluster * Return: 0 for success, -EIO on error */ static int fat_move_to_cluster(fat_itr *itr, unsigned int cluster) { unsigned int nbytes; /* position to the start of the directory */ itr->next_clust = cluster; itr->last_cluster = 0; if (!fat_next_cluster(itr, &nbytes)) return -EIO; itr->dent = (dir_entry *)itr->block; itr->remaining = nbytes / sizeof(dir_entry) - 1; return 0; } /** * set_name() - set short name in directory entry * * The function determines if the @filename is a valid short name. * In this case no long name is needed. * * If a long name is needed, a short name is constructed. * * @itr: directory iterator * @filename: long file name * @shortname: buffer of 11 bytes to receive chosen short name and extension * Return: number of directory entries needed, negative on error */ static int set_name(fat_itr *itr, const char *filename, char *shortname) { char *period; char *pos; int period_location; char buf[13]; int i; int ret; struct { char name[8]; char ext[3]; } dirent; if (!filename) return -EIO; /* Initialize buffer */ memset(&dirent, ' ', sizeof(dirent)); /* Convert filename to upper case short name */ period = strrchr(filename, '.'); pos = (char *)filename; if (*pos == '.') { pos = period + 1; period = 0; } if (period) str2fat(dirent.ext, period + 1, sizeof(dirent.ext)); period_location = str2fat(dirent.name, pos, sizeof(dirent.name)); if (period_location < 0) return period_location; if (*dirent.name == ' ') *dirent.name = '_'; /* 0xe5 signals a deleted directory entry. Replace it by 0x05. */ if (*dirent.name == 0xe5) *dirent.name = 0x05; /* If filename and short name are the same, quit. */ sprintf(buf, "%.*s.%.3s", period_location, dirent.name, dirent.ext); if (!strcmp(buf, filename)) { ret = 1; goto out; } /* Construct an indexed short name */ for (i = 1; i < 0x200000; ++i) { int suffix_len; int suffix_start; int j; /* To speed up the search use random numbers */ if (i < 10) { j = i; } else { j = 30 - fls(i); j = 10 + (rand() >> j); } sprintf(buf, "~%d", j); suffix_len = strlen(buf); suffix_start = 8 - suffix_len; if (suffix_start > period_location) suffix_start = period_location; memcpy(dirent.name + suffix_start, buf, suffix_len); if (*dirent.ext != ' ') sprintf(buf, "%.*s.%.3s", suffix_start + suffix_len, dirent.name, dirent.ext); else sprintf(buf, "%.*s", suffix_start + suffix_len, dirent.name); debug("generated short name: %s\n", buf); /* Check that the short name does not exist yet. */ ret = fat_move_to_cluster(itr, itr->start_clust); if (ret) return ret; if (find_directory_entry(itr, buf)) continue; debug("chosen short name: %s\n", buf); /* Each long name directory entry takes 13 characters. */ ret = (strlen(filename) + 25) / 13; goto out; } return -EIO; out: memcpy(shortname, dirent.name, SHORT_NAME_SIZE); return ret; } static int total_sector; static int disk_write(__u32 block, __u32 nr_blocks, void *buf) { ulong ret; if (!cur_dev) return -1; if (cur_part_info.start + block + nr_blocks > cur_part_info.start + total_sector) { printf("error: overflow occurs\n"); return -1; } ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf); if (nr_blocks && ret == 0) return -1; return ret; } /* * Write fat buffer into block device */ static int flush_dirty_fat_buffer(fsdata *mydata) { int getsize = FATBUFBLOCKS; __u32 fatlength = mydata->fatlength; __u8 *bufptr = mydata->fatbuf; __u32 startblock = mydata->fatbufnum * FATBUFBLOCKS; debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum, (int)mydata->fat_dirty); if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1)) return 0; /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */ if (startblock + getsize > fatlength) getsize = fatlength - startblock; startblock += mydata->fat_sect; /* Write FAT buf */ if (disk_write(startblock, getsize, bufptr) < 0) { debug("error: writing FAT blocks\n"); return -1; } if (mydata->fats == 2) { /* Update corresponding second FAT blocks */ startblock += mydata->fatlength; if (disk_write(startblock, getsize, bufptr) < 0) { debug("error: writing second FAT blocks\n"); return -1; } } mydata->fat_dirty = 0; return 0; } /** * fat_find_empty_dentries() - find a sequence of available directory entries * * @itr: directory iterator * @count: number of directory entries to find * Return: 0 on success or negative error number */ static int fat_find_empty_dentries(fat_itr *itr, int count) { unsigned int cluster; dir_entry *dent; int remaining; unsigned int n = 0; int ret; ret = fat_move_to_cluster(itr, itr->start_clust); if (ret) return ret; for (;;) { if (!itr->dent) { log_debug("Not enough directory entries available\n"); return -ENOSPC; } switch (itr->dent->name[0]) { case 0x00: case DELETED_FLAG: if (!n) { /* Remember first deleted directory entry */ cluster = itr->clust; dent = itr->dent; remaining = itr->remaining; } ++n; if (n == count) goto out; break; default: n = 0; break; } next_dent(itr); if (!itr->dent && (!itr->is_root || itr->fsdata->fatsize == 32) && new_dir_table(itr)) return -ENOSPC; } out: /* Position back to first directory entry */ if (itr->clust != cluster) { ret = fat_move_to_cluster(itr, cluster); if (ret) return ret; } itr->dent = dent; itr->remaining = remaining; return 0; } /* * Set the file name information from 'name' into 'slotptr', */ static int str2slot(dir_slot *slotptr, const char *name, int *idx) { int j, end_idx = 0; for (j = 0; j <= 8; j += 2) { if (name[*idx] == 0x00) { slotptr->name0_4[j] = 0; slotptr->name0_4[j + 1] = 0; end_idx++; goto name0_4; } slotptr->name0_4[j] = name[*idx]; (*idx)++; end_idx++; } for (j = 0; j <= 10; j += 2) { if (name[*idx] == 0x00) { slotptr->name5_10[j] = 0; slotptr->name5_10[j + 1] = 0; end_idx++; goto name5_10; } slotptr->name5_10[j] = name[*idx]; (*idx)++; end_idx++; } for (j = 0; j <= 2; j += 2) { if (name[*idx] == 0x00) { slotptr->name11_12[j] = 0; slotptr->name11_12[j + 1] = 0; end_idx++; goto name11_12; } slotptr->name11_12[j] = name[*idx]; (*idx)++; end_idx++; } if (name[*idx] == 0x00) return 1; return 0; /* Not used characters are filled with 0xff 0xff */ name0_4: for (; end_idx < 5; end_idx++) { slotptr->name0_4[end_idx * 2] = 0xff; slotptr->name0_4[end_idx * 2 + 1] = 0xff; } end_idx = 5; name5_10: end_idx -= 5; for (; end_idx < 6; end_idx++) { slotptr->name5_10[end_idx * 2] = 0xff; slotptr->name5_10[end_idx * 2 + 1] = 0xff; } end_idx = 11; name11_12: end_idx -= 11; for (; end_idx < 2; end_idx++) { slotptr->name11_12[end_idx * 2] = 0xff; slotptr->name11_12[end_idx * 2 + 1] = 0xff; } return 1; } static int flush_dir(fat_itr *itr); /** * fill_dir_slot() - fill directory entries for long name * * @itr: directory iterator * @l_name: long name * @shortname: short name * Return: 0 for success, -errno otherwise */ static int fill_dir_slot(fat_itr *itr, const char *l_name, const char *shortname) { __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)]; dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer; __u8 counter = 0, checksum; int idx = 0, ret; /* Get short file name checksum value */ checksum = mkcksum(shortname, shortname + 8); do { memset(slotptr, 0x00, sizeof(dir_slot)); ret = str2slot(slotptr, l_name, &idx); slotptr->id = ++counter; slotptr->attr = ATTR_VFAT; slotptr->alias_checksum = checksum; slotptr++; } while (ret == 0); slotptr--; slotptr->id |= LAST_LONG_ENTRY_MASK; while (counter >= 1) { memcpy(itr->dent, slotptr, sizeof(dir_slot)); slotptr--; counter--; if (itr->remaining == 0) flush_dir(itr); next_dent(itr); if (!itr->dent) return -EIO; } return 0; } /* * Set the entry at index 'entry' in a FAT (12/16/32) table. */ static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value) { __u32 bufnum, offset, off16; __u16 val1, val2; switch (mydata->fatsize) { case 32: bufnum = entry / FAT32BUFSIZE; offset = entry - bufnum * FAT32BUFSIZE; break; case 16: bufnum = entry / FAT16BUFSIZE; offset = entry - bufnum * FAT16BUFSIZE; break; case 12: bufnum = entry / FAT12BUFSIZE; offset = entry - bufnum * FAT12BUFSIZE; break; default: /* Unsupported FAT size */ return -1; } /* Read a new block of FAT entries into the cache. */ if (bufnum != mydata->fatbufnum) { int getsize = FATBUFBLOCKS; __u8 *bufptr = mydata->fatbuf; __u32 fatlength = mydata->fatlength; __u32 startblock = bufnum * FATBUFBLOCKS; /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */ if (startblock + getsize > fatlength) getsize = fatlength - startblock; if (flush_dirty_fat_buffer(mydata) < 0) return -1; startblock += mydata->fat_sect; if (disk_read(startblock, getsize, bufptr) < 0) { debug("Error reading FAT blocks\n"); return -1; } mydata->fatbufnum = bufnum; } /* Mark as dirty */ mydata->fat_dirty = 1; /* Set the actual entry */ switch (mydata->fatsize) { case 32: ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value); break; case 16: ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value); break; case 12: off16 = (offset * 3) / 4; switch (offset & 0x3) { case 0: val1 = cpu_to_le16(entry_value) & 0xfff; ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff; ((__u16 *)mydata->fatbuf)[off16] |= val1; break; case 1: val1 = cpu_to_le16(entry_value) & 0xf; val2 = (cpu_to_le16(entry_value) >> 4) & 0xff; ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000; ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12); ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff; ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2; break; case 2: val1 = cpu_to_le16(entry_value) & 0xff; val2 = (cpu_to_le16(entry_value) >> 8) & 0xf; ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00; ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8); ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf; ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2; break; case 3: val1 = cpu_to_le16(entry_value) & 0xfff; ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0; ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4); break; default: break; } break; default: return -1; } return 0; } /* * Determine the next free cluster after 'entry' in a FAT (12/16/32) table * and link it to 'entry'. EOC marker is not set on returned entry. */ static __u32 determine_fatent(fsdata *mydata, __u32 entry) { __u32 next_fat, next_entry = entry + 1; while (1) { next_fat = get_fatent(mydata, next_entry); if (next_fat == 0) { /* found free entry, link to entry */ set_fatent_value(mydata, entry, next_entry); break; } next_entry++; } debug("FAT%d: entry: %08x, entry_value: %04x\n", mydata->fatsize, entry, next_entry); return next_entry; } /** * set_sectors() - write data to sectors * * Write 'size' bytes from 'buffer' into the specified sector. * * @mydata: data to be written * @startsect: sector to be written to * @buffer: data to be written * @size: bytes to be written (but not more than the size of a cluster) * Return: 0 on success, -1 otherwise */ static int set_sectors(fsdata *mydata, u32 startsect, u8 *buffer, u32 size) { u32 nsects = 0; int ret; debug("startsect: %d\n", startsect); if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) { ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size); debug("FAT: Misaligned buffer address (%p)\n", buffer); while (size >= mydata->sect_size) { memcpy(tmpbuf, buffer, mydata->sect_size); ret = disk_write(startsect++, 1, tmpbuf); if (ret != 1) { debug("Error writing data (got %d)\n", ret); return -1; } buffer += mydata->sect_size; size -= mydata->sect_size; } } else if (size >= mydata->sect_size) { nsects = size / mydata->sect_size; ret = disk_write(startsect, nsects, buffer); if (ret != nsects) { debug("Error writing data (got %d)\n", ret); return -1; } startsect += nsects; buffer += nsects * mydata->sect_size; size -= nsects * mydata->sect_size; } if (size) { ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size); /* Do not leak content of stack */ memset(tmpbuf, 0, mydata->sect_size); memcpy(tmpbuf, buffer, size); ret = disk_write(startsect, 1, tmpbuf); if (ret != 1) { debug("Error writing data (got %d)\n", ret); return -1; } } return 0; } /** * set_cluster() - write data to cluster * * Write 'size' bytes from 'buffer' into the specified cluster. * * @mydata: data to be written * @clustnum: cluster to be written to * @buffer: data to be written * @size: bytes to be written (but not more than the size of a cluster) * Return: 0 on success, -1 otherwise */ static int set_cluster(fsdata *mydata, u32 clustnum, u8 *buffer, u32 size) { return set_sectors(mydata, clust_to_sect(mydata, clustnum), buffer, size); } static int flush_dir(fat_itr *itr) { fsdata *mydata = itr->fsdata; u32 startsect, sect_offset, nsects; if (!itr->is_root || mydata->fatsize == 32) return set_cluster(mydata, itr->clust, itr->block, mydata->clust_size * mydata->sect_size); sect_offset = itr->clust * mydata->clust_size; startsect = mydata->rootdir_sect + sect_offset; /* do not write past the end of rootdir */ nsects = min_t(u32, mydata->clust_size, mydata->rootdir_size - sect_offset); return set_sectors(mydata, startsect, itr->block, nsects * mydata->sect_size); } /* * Read and modify data on existing and consecutive cluster blocks */ static int get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer, loff_t size, loff_t *gotsize) { static u8 *tmpbuf_cluster; unsigned int bytesperclust = mydata->clust_size * mydata->sect_size; __u32 startsect; loff_t wsize; int clustcount, i, ret; *gotsize = 0; if (!size) return 0; if (!tmpbuf_cluster) { tmpbuf_cluster = memalign(ARCH_DMA_MINALIGN, MAX_CLUSTSIZE); if (!tmpbuf_cluster) return -1; } assert(pos < bytesperclust); startsect = clust_to_sect(mydata, clustnum); debug("clustnum: %d, startsect: %d, pos: %lld\n", clustnum, startsect, pos); /* partial write at beginning */ if (pos) { wsize = min(bytesperclust - pos, size); ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster); if (ret != mydata->clust_size) { debug("Error reading data (got %d)\n", ret); return -1; } memcpy(tmpbuf_cluster + pos, buffer, wsize); ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster); if (ret != mydata->clust_size) { debug("Error writing data (got %d)\n", ret); return -1; } size -= wsize; buffer += wsize; *gotsize += wsize; startsect += mydata->clust_size; if (!size) return 0; } /* full-cluster write */ if (size >= bytesperclust) { clustcount = lldiv(size, bytesperclust); if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) { wsize = clustcount * bytesperclust; ret = disk_write(startsect, clustcount * mydata->clust_size, buffer); if (ret != clustcount * mydata->clust_size) { debug("Error writing data (got %d)\n", ret); return -1; } size -= wsize; buffer += wsize; *gotsize += wsize; startsect += clustcount * mydata->clust_size; } else { for (i = 0; i < clustcount; i++) { memcpy(tmpbuf_cluster, buffer, bytesperclust); ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster); if (ret != mydata->clust_size) { debug("Error writing data (got %d)\n", ret); return -1; } size -= bytesperclust; buffer += bytesperclust; *gotsize += bytesperclust; startsect += mydata->clust_size; } } } /* partial write at end */ if (size) { wsize = size; ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster); if (ret != mydata->clust_size) { debug("Error reading data (got %d)\n", ret); return -1; } memcpy(tmpbuf_cluster, buffer, wsize); ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster); if (ret != mydata->clust_size) { debug("Error writing data (got %d)\n", ret); return -1; } size -= wsize; buffer += wsize; *gotsize += wsize; } assert(!size); return 0; } /* * Find the first empty cluster */ static int find_empty_cluster(fsdata *mydata) { __u32 fat_val, entry = 3; while (1) { fat_val = get_fatent(mydata, entry); if (fat_val == 0) break; entry++; } return entry; } /** * new_dir_table() - allocate a cluster for additional directory entries * * @itr: directory iterator * Return: 0 on success, -EIO otherwise */ static int new_dir_table(fat_itr *itr) { fsdata *mydata = itr->fsdata; int dir_newclust = 0; int dir_oldclust = itr->clust; unsigned int bytesperclust = mydata->clust_size * mydata->sect_size; dir_newclust = find_empty_cluster(mydata); /* * Flush before updating FAT to ensure valid directory structure * in case of failure. */ itr->clust = dir_newclust; itr->next_clust = dir_newclust; memset(itr->block, 0x00, bytesperclust); if (flush_dir(itr)) return -EIO; set_fatent_value(mydata, dir_oldclust, dir_newclust); if (mydata->fatsize == 32) set_fatent_value(mydata, dir_newclust, 0xffffff8); else if (mydata->fatsize == 16) set_fatent_value(mydata, dir_newclust, 0xfff8); else if (mydata->fatsize == 12) set_fatent_value(mydata, dir_newclust, 0xff8); if (flush_dirty_fat_buffer(mydata) < 0) return -EIO; itr->dent = (dir_entry *)itr->block; itr->last_cluster = 1; itr->remaining = bytesperclust / sizeof(dir_entry) - 1; return 0; } /* * Set empty cluster from 'entry' to the end of a file */ static int clear_fatent(fsdata *mydata, __u32 entry) { __u32 fat_val; while (!CHECK_CLUST(entry, mydata->fatsize)) { fat_val = get_fatent(mydata, entry); if (fat_val != 0) set_fatent_value(mydata, entry, 0); else break; entry = fat_val; } /* Flush fat buffer */ if (flush_dirty_fat_buffer(mydata) < 0) return -1; return 0; } /* * Set start cluster in directory entry */ static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr, __u32 start_cluster) { if (mydata->fatsize == 32) dentptr->starthi = cpu_to_le16((start_cluster & 0xffff0000) >> 16); dentptr->start = cpu_to_le16(start_cluster & 0xffff); } /* * Check whether adding a file makes the file system to * exceed the size of the block device * Return -1 when overflow occurs, otherwise return 0 */ static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size) { __u32 startsect, sect_num, offset; if (clustnum > 0) startsect = clust_to_sect(mydata, clustnum); else startsect = mydata->rootdir_sect; sect_num = div_u64_rem(size, mydata->sect_size, &offset); if (offset != 0) sect_num++; if (startsect + sect_num > total_sector) return -1; return 0; } /* * Write at most 'maxsize' bytes from 'buffer' into * the file associated with 'dentptr' * Update the number of bytes written in *gotsize and return 0 * or return -1 on fatal errors. */ static int set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer, loff_t maxsize, loff_t *gotsize) { unsigned int bytesperclust = mydata->clust_size * mydata->sect_size; __u32 curclust = START(dentptr); __u32 endclust = 0, newclust = 0; u64 cur_pos, filesize; loff_t offset, actsize, wsize; *gotsize = 0; filesize = pos + maxsize; debug("%llu bytes\n", filesize); if (!filesize) { if (!curclust) return 0; if (!CHECK_CLUST(curclust, mydata->fatsize) || IS_LAST_CLUST(curclust, mydata->fatsize)) { clear_fatent(mydata, curclust); set_start_cluster(mydata, dentptr, 0); return 0; } debug("curclust: 0x%x\n", curclust); debug("Invalid FAT entry\n"); return -1; } if (!curclust) { assert(pos == 0); goto set_clusters; } /* go to cluster at pos */ cur_pos = bytesperclust; while (1) { if (pos <= cur_pos) break; if (IS_LAST_CLUST(curclust, mydata->fatsize)) break; newclust = get_fatent(mydata, curclust); if (!IS_LAST_CLUST(newclust, mydata->fatsize) && CHECK_CLUST(newclust, mydata->fatsize)) { debug("curclust: 0x%x\n", curclust); debug("Invalid FAT entry\n"); return -1; } cur_pos += bytesperclust; curclust = newclust; } if (IS_LAST_CLUST(curclust, mydata->fatsize)) { assert(pos == cur_pos); goto set_clusters; } assert(pos < cur_pos); cur_pos -= bytesperclust; /* overwrite */ assert(IS_LAST_CLUST(curclust, mydata->fatsize) || !CHECK_CLUST(curclust, mydata->fatsize)); while (1) { /* search for allocated consecutive clusters */ actsize = bytesperclust; endclust = curclust; while (1) { if (filesize <= (cur_pos + actsize)) break; newclust = get_fatent(mydata, endclust); if (newclust != endclust + 1) break; if (IS_LAST_CLUST(newclust, mydata->fatsize)) break; if (CHECK_CLUST(newclust, mydata->fatsize)) { debug("curclust: 0x%x\n", curclust); debug("Invalid FAT entry\n"); return -1; } actsize += bytesperclust; endclust = newclust; } /* overwrite to */ if (pos < cur_pos) offset = 0; else offset = pos - cur_pos; wsize = min_t(unsigned long long, actsize, filesize - cur_pos); wsize -= offset; if (get_set_cluster(mydata, curclust, offset, buffer, wsize, &actsize)) { printf("Error get-and-setting cluster\n"); return -1; } buffer += wsize; *gotsize += wsize; cur_pos += offset + wsize; if (filesize <= cur_pos) break; if (IS_LAST_CLUST(newclust, mydata->fatsize)) /* no more clusters */ break; curclust = newclust; } if (filesize <= cur_pos) { /* no more write */ newclust = get_fatent(mydata, endclust); if (!IS_LAST_CLUST(newclust, mydata->fatsize)) { /* truncate the rest */ clear_fatent(mydata, newclust); /* Mark end of file in FAT */ if (mydata->fatsize == 12) newclust = 0xfff; else if (mydata->fatsize == 16) newclust = 0xffff; else if (mydata->fatsize == 32) newclust = 0xfffffff; set_fatent_value(mydata, endclust, newclust); } return 0; } curclust = endclust; filesize -= cur_pos; assert(!do_div(cur_pos, bytesperclust)); set_clusters: /* allocate and write */ assert(!pos); /* Assure that curclust is valid */ if (!curclust) { curclust = find_empty_cluster(mydata); set_start_cluster(mydata, dentptr, curclust); } else { newclust = get_fatent(mydata, curclust); if (IS_LAST_CLUST(newclust, mydata->fatsize)) { newclust = determine_fatent(mydata, curclust); set_fatent_value(mydata, curclust, newclust); curclust = newclust; } else { debug("error: something wrong\n"); return -1; } } /* TODO: already partially written */ if (check_overflow(mydata, curclust, filesize)) { printf("Error: no space left: %llu\n", filesize); return -1; } actsize = bytesperclust; endclust = curclust; do { /* search for consecutive clusters */ while (actsize < filesize) { newclust = determine_fatent(mydata, endclust); if ((newclust - 1) != endclust) /* write to */ goto getit; if (CHECK_CLUST(newclust, mydata->fatsize)) { debug("newclust: 0x%x\n", newclust); debug("Invalid FAT entry\n"); return 0; } endclust = newclust; actsize += bytesperclust; } /* set remaining bytes */ actsize = filesize; if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) { debug("error: writing cluster\n"); return -1; } *gotsize += actsize; /* Mark end of file in FAT */ if (mydata->fatsize == 12) newclust = 0xfff; else if (mydata->fatsize == 16) newclust = 0xffff; else if (mydata->fatsize == 32) newclust = 0xfffffff; set_fatent_value(mydata, endclust, newclust); return 0; getit: if (set_cluster(mydata, curclust, buffer, (u32)actsize) != 0) { debug("error: writing cluster\n"); return -1; } *gotsize += actsize; filesize -= actsize; buffer += actsize; if (CHECK_CLUST(newclust, mydata->fatsize)) { debug("newclust: 0x%x\n", newclust); debug("Invalid FAT entry\n"); return 0; } actsize = bytesperclust; curclust = endclust = newclust; } while (1); return 0; } /** * fill_dentry() - fill directory entry with shortname * * @mydata: private filesystem parameters * @dentptr: directory entry * @shortname: chosen short name * @start_cluster: first cluster of file * @size: file size * @attr: file attributes */ static void fill_dentry(fsdata *mydata, dir_entry *dentptr, const char *shortname, __u32 start_cluster, __u32 size, __u8 attr) { memset(dentptr, 0, sizeof(*dentptr)); set_start_cluster(mydata, dentptr, start_cluster); dentptr->size = cpu_to_le32(size); dentptr->attr = attr; memcpy(dentptr->name, shortname, SHORT_NAME_SIZE); } /** * find_directory_entry() - find a directory entry by filename * * @itr: directory iterator * @filename: name of file to find * Return: directory entry or NULL */ static dir_entry *find_directory_entry(fat_itr *itr, char *filename) { int match = 0; while (fat_itr_next(itr)) { /* check both long and short name: */ if (!strcasecmp(filename, itr->name)) match = 1; else if (itr->name != itr->s_name && !strcasecmp(filename, itr->s_name)) match = 1; if (!match) continue; if (itr->dent->name[0] == '\0') return NULL; else return itr->dent; } return NULL; } static int split_filename(char *filename, char **dirname, char **basename) { char *p, *last_slash, *last_slash_cont; again: p = filename; last_slash = NULL; last_slash_cont = NULL; while (*p) { if (ISDIRDELIM(*p)) { last_slash = p; last_slash_cont = p; /* continuous slashes */ while (ISDIRDELIM(*p)) last_slash_cont = p++; if (!*p) break; } p++; } if (last_slash) { if (last_slash_cont == (filename + strlen(filename) - 1)) { /* remove trailing slashes */ *last_slash = '\0'; goto again; } if (last_slash == filename) { /* avoid ""(null) directory */ *dirname = "/"; } else { *last_slash = '\0'; *dirname = filename; } *last_slash_cont = '\0'; *basename = last_slash_cont + 1; } else { *dirname = "/"; /* root by default */ *basename = filename; } return 0; } /** * normalize_longname() - check long file name and convert to lower case * * We assume here that the FAT file system is using an 8bit code page. * Linux typically uses CP437, EDK2 assumes CP1250. * * @l_filename: preallocated buffer receiving the normalized name * @filename: filename to normalize * Return: 0 on success, -1 on failure */ static int normalize_longname(char *l_filename, const char *filename) { const char *p, illegal[] = "<>:\"/\\|?*"; if (strlen(filename) >= VFAT_MAXLEN_BYTES) return -1; for (p = filename; *p; ++p) { if ((unsigned char)*p < 0x20) return -1; if (strchr(illegal, *p)) return -1; } strcpy(l_filename, filename); downcase(l_filename, VFAT_MAXLEN_BYTES); return 0; } int file_fat_write_at(const char *filename, loff_t pos, void *buffer, loff_t size, loff_t *actwrite) { dir_entry *retdent; fsdata datablock = { .fatbuf = NULL, }; fsdata *mydata = &datablock; fat_itr *itr = NULL; int ret = -1; char *filename_copy, *parent, *basename; char l_filename[VFAT_MAXLEN_BYTES]; debug("writing %s\n", filename); filename_copy = strdup(filename); if (!filename_copy) return -ENOMEM; split_filename(filename_copy, &parent, &basename); if (!strlen(basename)) { ret = -EINVAL; goto exit; } filename = basename; if (normalize_longname(l_filename, filename)) { printf("FAT: illegal filename (%s)\n", filename); ret = -EINVAL; goto exit; } itr = malloc_cache_aligned(sizeof(fat_itr)); if (!itr) { ret = -ENOMEM; goto exit; } ret = fat_itr_root(itr, &datablock); if (ret) goto exit; total_sector = datablock.total_sect; ret = fat_itr_resolve(itr, parent, TYPE_DIR); if (ret) { printf("%s: doesn't exist (%d)\n", parent, ret); goto exit; } retdent = find_directory_entry(itr, l_filename); if (retdent) { if (fat_itr_isdir(itr)) { ret = -EISDIR; goto exit; } /* A file exists */ if (pos == -1) /* Append to the end */ pos = FAT2CPU32(retdent->size); if (pos > retdent->size) { /* No hole allowed */ ret = -EINVAL; goto exit; } /* Update file size in a directory entry */ retdent->size = cpu_to_le32(pos + size); } else { /* Create a new file */ char shortname[SHORT_NAME_SIZE]; int ndent; if (itr->is_root) { /* root dir cannot have "." or ".." */ if (!strcmp(l_filename, ".") || !strcmp(l_filename, "..")) { ret = -EINVAL; goto exit; } } if (pos) { /* No hole allowed */ ret = -EINVAL; goto exit; } /* Check if long name is needed */ ndent = set_name(itr, filename, shortname); if (ndent < 0) { ret = ndent; goto exit; } ret = fat_find_empty_dentries(itr, ndent); if (ret) goto exit; if (ndent > 1) { /* Set long name entries */ ret = fill_dir_slot(itr, filename, shortname); if (ret) goto exit; } /* Set short name entry */ fill_dentry(itr->fsdata, itr->dent, shortname, 0, size, ATTR_ARCH); retdent = itr->dent; } ret = set_contents(mydata, retdent, pos, buffer, size, actwrite); if (ret < 0) { printf("Error: writing contents\n"); ret = -EIO; goto exit; } debug("attempt to write 0x%llx bytes\n", *actwrite); /* Flush fat buffer */ ret = flush_dirty_fat_buffer(mydata); if (ret) { printf("Error: flush fat buffer\n"); ret = -EIO; goto exit; } /* Write directory table to device */ ret = flush_dir(itr); if (ret) { printf("Error: writing directory entry\n"); ret = -EIO; } exit: free(filename_copy); free(mydata->fatbuf); free(itr); return ret; } int file_fat_write(const char *filename, void *buffer, loff_t offset, loff_t maxsize, loff_t *actwrite) { return file_fat_write_at(filename, offset, buffer, maxsize, actwrite); } static int fat_dir_entries(fat_itr *itr) { fat_itr *dirs; fsdata fsdata = { .fatbuf = NULL, }, *mydata = &fsdata; /* for FATBUFSIZE */ int count; dirs = malloc_cache_aligned(sizeof(fat_itr)); if (!dirs) { debug("Error: allocating memory\n"); count = -ENOMEM; goto exit; } /* duplicate fsdata */ fat_itr_child(dirs, itr); fsdata = *dirs->fsdata; /* allocate local fat buffer */ fsdata.fatbuf = malloc_cache_aligned(FATBUFSIZE); if (!fsdata.fatbuf) { debug("Error: allocating memory\n"); count = -ENOMEM; goto exit; } fsdata.fatbufnum = -1; dirs->fsdata = &fsdata; for (count = 0; fat_itr_next(dirs); count++) ; exit: free(fsdata.fatbuf); free(dirs); return count; } static int delete_dentry(fat_itr *itr) { fsdata *mydata = itr->fsdata; dir_entry *dentptr = itr->dent; /* free cluster blocks */ clear_fatent(mydata, START(dentptr)); if (flush_dirty_fat_buffer(mydata) < 0) { printf("Error: flush fat buffer\n"); return -EIO; } /* * update a directory entry * TODO: * - long file name support * - find and mark the "new" first invalid entry as name[0]=0x00 */ memset(dentptr, 0, sizeof(*dentptr)); dentptr->name[0] = DELETED_FLAG; if (flush_dir(itr)) { printf("error: writing directory entry\n"); return -EIO; } return 0; } int fat_unlink(const char *filename) { fsdata fsdata = { .fatbuf = NULL, }; fat_itr *itr = NULL; int n_entries, ret; char *filename_copy, *dirname, *basename; filename_copy = strdup(filename); if (!filename_copy) { printf("Error: allocating memory\n"); ret = -ENOMEM; goto exit; } split_filename(filename_copy, &dirname, &basename); if (!strcmp(dirname, "/") && !strcmp(basename, "")) { printf("Error: cannot remove root\n"); ret = -EINVAL; goto exit; } itr = malloc_cache_aligned(sizeof(fat_itr)); if (!itr) { printf("Error: allocating memory\n"); ret = -ENOMEM; goto exit; } ret = fat_itr_root(itr, &fsdata); if (ret) goto exit; total_sector = fsdata.total_sect; ret = fat_itr_resolve(itr, dirname, TYPE_DIR); if (ret) { printf("%s: doesn't exist (%d)\n", dirname, ret); ret = -ENOENT; goto exit; } if (!find_directory_entry(itr, basename)) { printf("%s: doesn't exist\n", basename); ret = -ENOENT; goto exit; } if (fat_itr_isdir(itr)) { n_entries = fat_dir_entries(itr); if (n_entries < 0) { ret = n_entries; goto exit; } if (n_entries > 2) { printf("Error: directory is not empty: %d\n", n_entries); ret = -EINVAL; goto exit; } } ret = delete_dentry(itr); exit: free(fsdata.fatbuf); free(itr); free(filename_copy); return ret; } int fat_mkdir(const char *new_dirname) { dir_entry *retdent; fsdata datablock = { .fatbuf = NULL, }; fsdata *mydata = &datablock; fat_itr *itr = NULL; char *dirname_copy, *parent, *dirname; char l_dirname[VFAT_MAXLEN_BYTES]; int ret = -1; loff_t actwrite; unsigned int bytesperclust; dir_entry *dotdent = NULL; dirname_copy = strdup(new_dirname); if (!dirname_copy) goto exit; split_filename(dirname_copy, &parent, &dirname); if (!strlen(dirname)) { ret = -EINVAL; goto exit; } if (normalize_longname(l_dirname, dirname)) { printf("FAT: illegal filename (%s)\n", dirname); ret = -EINVAL; goto exit; } itr = malloc_cache_aligned(sizeof(fat_itr)); if (!itr) { ret = -ENOMEM; goto exit; } ret = fat_itr_root(itr, &datablock); if (ret) goto exit; total_sector = datablock.total_sect; ret = fat_itr_resolve(itr, parent, TYPE_DIR); if (ret) { printf("%s: doesn't exist (%d)\n", parent, ret); goto exit; } retdent = find_directory_entry(itr, l_dirname); if (retdent) { printf("%s: already exists\n", l_dirname); ret = -EEXIST; goto exit; } else { char shortname[SHORT_NAME_SIZE]; int ndent; if (itr->is_root) { /* root dir cannot have "." or ".." */ if (!strcmp(l_dirname, ".") || !strcmp(l_dirname, "..")) { ret = -EINVAL; goto exit; } } /* Check if long name is needed */ ndent = set_name(itr, dirname, shortname); if (ndent < 0) { ret = ndent; goto exit; } ret = fat_find_empty_dentries(itr, ndent); if (ret) goto exit; if (ndent > 1) { /* Set long name entries */ ret = fill_dir_slot(itr, dirname, shortname); if (ret) goto exit; } /* Set attribute as archive for regular file */ fill_dentry(itr->fsdata, itr->dent, shortname, 0, 0, ATTR_DIR | ATTR_ARCH); retdent = itr->dent; } /* Default entries */ bytesperclust = mydata->clust_size * mydata->sect_size; dotdent = malloc_cache_aligned(bytesperclust); if (!dotdent) { ret = -ENOMEM; goto exit; } memset(dotdent, 0, bytesperclust); memcpy(dotdent[0].name, ". ", 8); memcpy(dotdent[0].ext, " ", 3); dotdent[0].attr = ATTR_DIR | ATTR_ARCH; memcpy(dotdent[1].name, ".. ", 8); memcpy(dotdent[1].ext, " ", 3); dotdent[1].attr = ATTR_DIR | ATTR_ARCH; if (itr->is_root) set_start_cluster(mydata, &dotdent[1], 0); else set_start_cluster(mydata, &dotdent[1], itr->start_clust); ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent, bytesperclust, &actwrite); if (ret < 0) { printf("Error: writing contents\n"); goto exit; } /* Write twice for "." */ set_start_cluster(mydata, &dotdent[0], START(retdent)); ret = set_contents(mydata, retdent, 0, (__u8 *)dotdent, bytesperclust, &actwrite); if (ret < 0) { printf("Error: writing contents\n"); goto exit; } /* Flush fat buffer */ ret = flush_dirty_fat_buffer(mydata); if (ret) { printf("Error: flush fat buffer\n"); goto exit; } /* Write directory table to device */ ret = flush_dir(itr); if (ret) printf("Error: writing directory entry\n"); exit: free(dirname_copy); free(mydata->fatbuf); free(itr); free(dotdent); return ret; }