Mercurial > pihelp
view fat.c @ 49:12236bceb6b0 default tip
snapshot export of the schematic
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Wed, 25 Jun 2014 21:29:52 +0800 |
| parents | 5f9a40d6991b |
| children |
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/* * Copyright (c) 2006-2012 by Roland Riegel <[email protected]> * * This file is free software; you can redistribute it and/or modify * it under the terms of either the GNU General Public License version 2 * or the GNU Lesser General Public License version 2.1, both as * published by the Free Software Foundation. */ #include "byteordering.h" #include "partition.h" #include "fat.h" #include "fat_config.h" #include "sd-reader_config.h" #include <string.h> #if USE_DYNAMIC_MEMORY #include <stdlib.h> #endif /** * \addtogroup fat FAT support * * This module implements FAT16/FAT32 read and write access. * * The following features are supported: * - File names up to 31 characters long. * - Unlimited depth of subdirectories. * - Short 8.3 and long filenames. * - Creating and deleting files. * - Reading and writing from and to files. * - File resizing. * - File sizes of up to 4 gigabytes. * * @{ */ /** * \file * FAT implementation (license: GPLv2 or LGPLv2.1) * * \author Roland Riegel */ /** * \addtogroup fat_config FAT configuration * Preprocessor defines to configure the FAT implementation. */ /** * \addtogroup fat_fs FAT access * Basic functions for handling a FAT filesystem. */ /** * \addtogroup fat_file FAT file functions * Functions for managing files. */ /** * \addtogroup fat_dir FAT directory functions * Functions for managing directories. */ /** * @} */ #define FAT16_CLUSTER_FREE 0x0000 #define FAT16_CLUSTER_RESERVED_MIN 0xfff0 #define FAT16_CLUSTER_RESERVED_MAX 0xfff6 #define FAT16_CLUSTER_BAD 0xfff7 #define FAT16_CLUSTER_LAST_MIN 0xfff8 #define FAT16_CLUSTER_LAST_MAX 0xffff #define FAT32_CLUSTER_FREE 0x00000000 #define FAT32_CLUSTER_RESERVED_MIN 0x0ffffff0 #define FAT32_CLUSTER_RESERVED_MAX 0x0ffffff6 #define FAT32_CLUSTER_BAD 0x0ffffff7 #define FAT32_CLUSTER_LAST_MIN 0x0ffffff8 #define FAT32_CLUSTER_LAST_MAX 0x0fffffff #define FAT_DIRENTRY_DELETED 0xe5 #define FAT_DIRENTRY_LFNLAST (1 << 6) #define FAT_DIRENTRY_LFNSEQMASK ((1 << 6) - 1) /* Each entry within the directory table has a size of 32 bytes * and either contains a 8.3 DOS-style file name or a part of a * long file name, which may consist of several directory table * entries at once. * * multi-byte integer values are stored little-endian! * * 8.3 file name entry: * ==================== * offset length description * 0 8 name (space padded) * 8 3 extension (space padded) * 11 1 attributes (FAT_ATTRIB_*) * * long file name (lfn) entry ordering for a single file name: * =========================================================== * LFN entry n * ... * LFN entry 2 * LFN entry 1 * 8.3 entry (see above) * * lfn entry: * ========== * offset length description * 0 1 ordinal field * 1 2 unicode character 1 * 3 3 unicode character 2 * 5 3 unicode character 3 * 7 3 unicode character 4 * 9 3 unicode character 5 * 11 1 attribute (always 0x0f) * 12 1 type (reserved, always 0) * 13 1 checksum * 14 2 unicode character 6 * 16 2 unicode character 7 * 18 2 unicode character 8 * 20 2 unicode character 9 * 22 2 unicode character 10 * 24 2 unicode character 11 * 26 2 cluster (unused, always 0) * 28 2 unicode character 12 * 30 2 unicode character 13 * * The ordinal field contains a descending number, from n to 1. * For the n'th lfn entry the ordinal field is or'ed with 0x40. * For deleted lfn entries, the ordinal field is set to 0xe5. */ struct fat_header_struct { offset_t size; offset_t fat_offset; uint32_t fat_size; uint16_t sector_size; uint16_t cluster_size; offset_t cluster_zero_offset; offset_t root_dir_offset; #if FAT_FAT32_SUPPORT cluster_t root_dir_cluster; #endif }; struct fat_fs_struct { struct partition_struct* partition; struct fat_header_struct header; cluster_t cluster_free; }; struct fat_file_struct { struct fat_fs_struct* fs; struct fat_dir_entry_struct dir_entry; offset_t pos; cluster_t pos_cluster; }; struct fat_dir_struct { struct fat_fs_struct* fs; struct fat_dir_entry_struct dir_entry; cluster_t entry_cluster; uint16_t entry_offset; }; struct fat_read_dir_callback_arg { struct fat_dir_entry_struct* dir_entry; uintptr_t bytes_read; #if FAT_LFN_SUPPORT uint8_t checksum; #endif uint8_t finished; }; struct fat_usage_count_callback_arg { cluster_t cluster_count; uintptr_t buffer_size; }; #if !USE_DYNAMIC_MEMORY static struct fat_fs_struct fat_fs_handles[FAT_FS_COUNT]; static struct fat_file_struct fat_file_handles[FAT_FILE_COUNT]; static struct fat_dir_struct fat_dir_handles[FAT_DIR_COUNT]; #endif static uint8_t fat_read_header(struct fat_fs_struct* fs); static cluster_t fat_get_next_cluster(const struct fat_fs_struct* fs, cluster_t cluster_num); static offset_t fat_cluster_offset(const struct fat_fs_struct* fs, cluster_t cluster_num); static uint8_t fat_dir_entry_read_callback(uint8_t* buffer, offset_t offset, void* p); #if FAT_LFN_SUPPORT static uint8_t fat_calc_83_checksum(const uint8_t* file_name_83); #endif static uint8_t fat_get_fs_free_16_callback(uint8_t* buffer, offset_t offset, void* p); #if FAT_FAT32_SUPPORT static uint8_t fat_get_fs_free_32_callback(uint8_t* buffer, offset_t offset, void* p); #endif #if FAT_WRITE_SUPPORT static cluster_t fat_append_clusters(struct fat_fs_struct* fs, cluster_t cluster_num, cluster_t count); static uint8_t fat_free_clusters(struct fat_fs_struct* fs, cluster_t cluster_num); static uint8_t fat_terminate_clusters(struct fat_fs_struct* fs, cluster_t cluster_num); static uint8_t fat_clear_cluster(const struct fat_fs_struct* fs, cluster_t cluster_num); static uintptr_t fat_clear_cluster_callback(uint8_t* buffer, offset_t offset, void* p); static offset_t fat_find_offset_for_dir_entry(struct fat_fs_struct* fs, const struct fat_dir_struct* parent, const struct fat_dir_entry_struct* dir_entry); static uint8_t fat_write_dir_entry(const struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry); #if FAT_DATETIME_SUPPORT static void fat_set_file_modification_date(struct fat_dir_entry_struct* dir_entry, uint16_t year, uint8_t month, uint8_t day); static void fat_set_file_modification_time(struct fat_dir_entry_struct* dir_entry, uint8_t hour, uint8_t min, uint8_t sec); #endif #endif /** * \ingroup fat_fs * Opens a FAT filesystem. * * \param[in] partition Discriptor of partition on which the filesystem resides. * \returns 0 on error, a FAT filesystem descriptor on success. * \see fat_close */ struct fat_fs_struct* fat_open(struct partition_struct* partition) { if(!partition || #if FAT_WRITE_SUPPORT !partition->device_write || !partition->device_write_interval #else 0 #endif ) return 0; #if USE_DYNAMIC_MEMORY struct fat_fs_struct* fs = malloc(sizeof(*fs)); if(!fs) return 0; #else struct fat_fs_struct* fs = fat_fs_handles; uint8_t i; for(i = 0; i < FAT_FS_COUNT; ++i) { if(!fs->partition) break; ++fs; } if(i >= FAT_FS_COUNT) return 0; #endif memset(fs, 0, sizeof(*fs)); fs->partition = partition; if(!fat_read_header(fs)) { #if USE_DYNAMIC_MEMORY free(fs); #else fs->partition = 0; #endif return 0; } return fs; } /** * \ingroup fat_fs * Closes a FAT filesystem. * * When this function returns, the given filesystem descriptor * will be invalid. * * \param[in] fs The filesystem to close. * \see fat_open */ void fat_close(struct fat_fs_struct* fs) { if(!fs) return; #if USE_DYNAMIC_MEMORY free(fs); #else fs->partition = 0; #endif } /** * \ingroup fat_fs * Reads and parses the header of a FAT filesystem. * * \param[in,out] fs The filesystem for which to parse the header. * \returns 0 on failure, 1 on success. */ uint8_t fat_read_header(struct fat_fs_struct* fs) { if(!fs) return 0; struct partition_struct* partition = fs->partition; if(!partition) return 0; /* read fat parameters */ #if FAT_FAT32_SUPPORT uint8_t buffer[37]; #else uint8_t buffer[25]; #endif offset_t partition_offset = (offset_t) partition->offset * 512; if(!partition->device_read(partition_offset + 0x0b, buffer, sizeof(buffer))) return 0; uint16_t bytes_per_sector = read16(&buffer[0x00]); uint16_t reserved_sectors = read16(&buffer[0x03]); uint8_t sectors_per_cluster = buffer[0x02]; uint8_t fat_copies = buffer[0x05]; uint16_t max_root_entries = read16(&buffer[0x06]); uint16_t sector_count_16 = read16(&buffer[0x08]); uint16_t sectors_per_fat = read16(&buffer[0x0b]); uint32_t sector_count = read32(&buffer[0x15]); #if FAT_FAT32_SUPPORT uint32_t sectors_per_fat32 = read32(&buffer[0x19]); uint32_t cluster_root_dir = read32(&buffer[0x21]); #endif if(sector_count == 0) { if(sector_count_16 == 0) /* illegal volume size */ return 0; else sector_count = sector_count_16; } #if FAT_FAT32_SUPPORT if(sectors_per_fat != 0) sectors_per_fat32 = sectors_per_fat; else if(sectors_per_fat32 == 0) /* this is neither FAT16 nor FAT32 */ return 0; #else if(sectors_per_fat == 0) /* this is not a FAT16 */ return 0; #endif /* determine the type of FAT we have here */ uint32_t data_sector_count = sector_count - reserved_sectors #if FAT_FAT32_SUPPORT - sectors_per_fat32 * fat_copies #else - (uint32_t) sectors_per_fat * fat_copies #endif - ((max_root_entries * 32 + bytes_per_sector - 1) / bytes_per_sector); uint32_t data_cluster_count = data_sector_count / sectors_per_cluster; if(data_cluster_count < 4085) /* this is a FAT12, not supported */ return 0; else if(data_cluster_count < 65525) /* this is a FAT16 */ partition->type = PARTITION_TYPE_FAT16; else /* this is a FAT32 */ partition->type = PARTITION_TYPE_FAT32; /* fill header information */ struct fat_header_struct* header = &fs->header; memset(header, 0, sizeof(*header)); header->size = (offset_t) sector_count * bytes_per_sector; header->fat_offset = /* jump to partition */ partition_offset + /* jump to fat */ (offset_t) reserved_sectors * bytes_per_sector; header->fat_size = (data_cluster_count + 2) * (partition->type == PARTITION_TYPE_FAT16 ? 2 : 4); header->sector_size = bytes_per_sector; header->cluster_size = (uint16_t) bytes_per_sector * sectors_per_cluster; #if FAT_FAT32_SUPPORT if(partition->type == PARTITION_TYPE_FAT16) #endif { header->root_dir_offset = /* jump to fats */ header->fat_offset + /* jump to root directory entries */ (offset_t) fat_copies * sectors_per_fat * bytes_per_sector; header->cluster_zero_offset = /* jump to root directory entries */ header->root_dir_offset + /* skip root directory entries */ (offset_t) max_root_entries * 32; } #if FAT_FAT32_SUPPORT else { header->cluster_zero_offset = /* jump to fats */ header->fat_offset + /* skip fats */ (offset_t) fat_copies * sectors_per_fat32 * bytes_per_sector; header->root_dir_cluster = cluster_root_dir; } #endif return 1; } /** * \ingroup fat_fs * Retrieves the next following cluster of a given cluster. * * Using the filesystem file allocation table, this function returns * the number of the cluster containing the data directly following * the data within the cluster with the given number. * * \param[in] fs The filesystem for which to determine the next cluster. * \param[in] cluster_num The number of the cluster for which to determine its successor. * \returns The wanted cluster number, or 0 on error. */ cluster_t fat_get_next_cluster(const struct fat_fs_struct* fs, cluster_t cluster_num) { if(!fs || cluster_num < 2) return 0; #if FAT_FAT32_SUPPORT if(fs->partition->type == PARTITION_TYPE_FAT32) { /* read appropriate fat entry */ uint32_t fat_entry; if(!fs->partition->device_read(fs->header.fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry))) return 0; /* determine next cluster from fat */ cluster_num = ltoh32(fat_entry); if(cluster_num == FAT32_CLUSTER_FREE || cluster_num == FAT32_CLUSTER_BAD || (cluster_num >= FAT32_CLUSTER_RESERVED_MIN && cluster_num <= FAT32_CLUSTER_RESERVED_MAX) || (cluster_num >= FAT32_CLUSTER_LAST_MIN && cluster_num <= FAT32_CLUSTER_LAST_MAX)) return 0; } else #endif { /* read appropriate fat entry */ uint16_t fat_entry; if(!fs->partition->device_read(fs->header.fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry))) return 0; /* determine next cluster from fat */ cluster_num = ltoh16(fat_entry); if(cluster_num == FAT16_CLUSTER_FREE || cluster_num == FAT16_CLUSTER_BAD || (cluster_num >= FAT16_CLUSTER_RESERVED_MIN && cluster_num <= FAT16_CLUSTER_RESERVED_MAX) || (cluster_num >= FAT16_CLUSTER_LAST_MIN && cluster_num <= FAT16_CLUSTER_LAST_MAX)) return 0; } return cluster_num; } #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Appends a new cluster chain to an existing one. * * Set cluster_num to zero to create a completely new one. * * \param[in] fs The file system on which to operate. * \param[in] cluster_num The cluster to which to append the new chain. * \param[in] count The number of clusters to allocate. * \returns 0 on failure, the number of the first new cluster on success. */ cluster_t fat_append_clusters(struct fat_fs_struct* fs, cluster_t cluster_num, cluster_t count) { if(!fs) return 0; device_read_t device_read = fs->partition->device_read; device_write_t device_write = fs->partition->device_write; offset_t fat_offset = fs->header.fat_offset; cluster_t count_left = count; cluster_t cluster_current = fs->cluster_free; cluster_t cluster_next = 0; cluster_t cluster_count; uint16_t fat_entry16; #if FAT_FAT32_SUPPORT uint32_t fat_entry32; uint8_t is_fat32 = (fs->partition->type == PARTITION_TYPE_FAT32); if(is_fat32) cluster_count = fs->header.fat_size / sizeof(fat_entry32); else #endif cluster_count = fs->header.fat_size / sizeof(fat_entry16); fs->cluster_free = 0; for(cluster_t cluster_left = cluster_count; cluster_left > 0; --cluster_left, ++cluster_current) { if(cluster_current < 2 || cluster_current >= cluster_count) cluster_current = 2; #if FAT_FAT32_SUPPORT if(is_fat32) { if(!device_read(fat_offset + (offset_t) cluster_current * sizeof(fat_entry32), (uint8_t*) &fat_entry32, sizeof(fat_entry32))) return 0; } else #endif { if(!device_read(fat_offset + (offset_t) cluster_current * sizeof(fat_entry16), (uint8_t*) &fat_entry16, sizeof(fat_entry16))) return 0; } #if FAT_FAT32_SUPPORT if(is_fat32) { /* check if this is a free cluster */ if(fat_entry32 != HTOL32(FAT32_CLUSTER_FREE)) continue; /* If we don't need this free cluster for the * current allocation, we keep it in mind for * the next time. */ if(count_left == 0) { fs->cluster_free = cluster_current; break; } /* allocate cluster */ if(cluster_next == 0) fat_entry32 = HTOL32(FAT32_CLUSTER_LAST_MAX); else fat_entry32 = htol32(cluster_next); if(!device_write(fat_offset + (offset_t) cluster_current * sizeof(fat_entry32), (uint8_t*) &fat_entry32, sizeof(fat_entry32))) break; } else #endif { /* check if this is a free cluster */ if(fat_entry16 != HTOL16(FAT16_CLUSTER_FREE)) continue; /* If we don't need this free cluster for the * current allocation, we keep it in mind for * the next time. */ if(count_left == 0) { fs->cluster_free = cluster_current; break; } /* allocate cluster */ if(cluster_next == 0) fat_entry16 = HTOL16(FAT16_CLUSTER_LAST_MAX); else fat_entry16 = htol16((uint16_t) cluster_next); if(!device_write(fat_offset + (offset_t) cluster_current * sizeof(fat_entry16), (uint8_t*) &fat_entry16, sizeof(fat_entry16))) break; } cluster_next = cluster_current; --count_left; } do { if(count_left > 0) break; /* We allocated a new cluster chain. Now join * it with the existing one (if any). */ if(cluster_num >= 2) { #if FAT_FAT32_SUPPORT if(is_fat32) { fat_entry32 = htol32(cluster_next); if(!device_write(fat_offset + (offset_t) cluster_num * sizeof(fat_entry32), (uint8_t*) &fat_entry32, sizeof(fat_entry32))) break; } else #endif { fat_entry16 = htol16((uint16_t) cluster_next); if(!device_write(fat_offset + (offset_t) cluster_num * sizeof(fat_entry16), (uint8_t*) &fat_entry16, sizeof(fat_entry16))) break; } } return cluster_next; } while(0); /* No space left on device or writing error. * Free up all clusters already allocated. */ fat_free_clusters(fs, cluster_next); return 0; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Frees a cluster chain, or a part thereof. * * Marks the specified cluster and all clusters which are sequentially * referenced by it as free. They may then be used again for future * file allocations. * * \note If this function is used for freeing just a part of a cluster * chain, the new end of the chain is not correctly terminated * within the FAT. Use fat_terminate_clusters() instead. * * \param[in] fs The filesystem on which to operate. * \param[in] cluster_num The starting cluster of the chain which to free. * \returns 0 on failure, 1 on success. * \see fat_terminate_clusters */ uint8_t fat_free_clusters(struct fat_fs_struct* fs, cluster_t cluster_num) { if(!fs || cluster_num < 2) return 0; offset_t fat_offset = fs->header.fat_offset; #if FAT_FAT32_SUPPORT if(fs->partition->type == PARTITION_TYPE_FAT32) { uint32_t fat_entry; while(cluster_num) { if(!fs->partition->device_read(fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry))) return 0; /* get next cluster of current cluster before freeing current cluster */ uint32_t cluster_num_next = ltoh32(fat_entry); if(cluster_num_next == FAT32_CLUSTER_FREE) return 1; if(cluster_num_next == FAT32_CLUSTER_BAD || (cluster_num_next >= FAT32_CLUSTER_RESERVED_MIN && cluster_num_next <= FAT32_CLUSTER_RESERVED_MAX ) ) return 0; if(cluster_num_next >= FAT32_CLUSTER_LAST_MIN && cluster_num_next <= FAT32_CLUSTER_LAST_MAX) cluster_num_next = 0; /* We know we will free the cluster, so remember it as * free for the next allocation. */ if(!fs->cluster_free) fs->cluster_free = cluster_num; /* free cluster */ fat_entry = HTOL32(FAT32_CLUSTER_FREE); fs->partition->device_write(fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry)); /* We continue in any case here, even if freeing the cluster failed. * The cluster is lost, but maybe we can still free up some later ones. */ cluster_num = cluster_num_next; } } else #endif { uint16_t fat_entry; while(cluster_num) { if(!fs->partition->device_read(fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry))) return 0; /* get next cluster of current cluster before freeing current cluster */ uint16_t cluster_num_next = ltoh16(fat_entry); if(cluster_num_next == FAT16_CLUSTER_FREE) return 1; if(cluster_num_next == FAT16_CLUSTER_BAD || (cluster_num_next >= FAT16_CLUSTER_RESERVED_MIN && cluster_num_next <= FAT16_CLUSTER_RESERVED_MAX ) ) return 0; if(cluster_num_next >= FAT16_CLUSTER_LAST_MIN && cluster_num_next <= FAT16_CLUSTER_LAST_MAX) cluster_num_next = 0; /* free cluster */ fat_entry = HTOL16(FAT16_CLUSTER_FREE); fs->partition->device_write(fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry)); /* We continue in any case here, even if freeing the cluster failed. * The cluster is lost, but maybe we can still free up some later ones. */ cluster_num = cluster_num_next; } } return 1; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Frees a part of a cluster chain and correctly terminates the rest. * * Marks the specified cluster as the new end of a cluster chain and * frees all following clusters. * * \param[in] fs The filesystem on which to operate. * \param[in] cluster_num The new end of the cluster chain. * \returns 0 on failure, 1 on success. * \see fat_free_clusters */ uint8_t fat_terminate_clusters(struct fat_fs_struct* fs, cluster_t cluster_num) { if(!fs || cluster_num < 2) return 0; /* fetch next cluster before overwriting the cluster entry */ cluster_t cluster_num_next = fat_get_next_cluster(fs, cluster_num); /* mark cluster as the last one */ #if FAT_FAT32_SUPPORT if(fs->partition->type == PARTITION_TYPE_FAT32) { uint32_t fat_entry = HTOL32(FAT32_CLUSTER_LAST_MAX); if(!fs->partition->device_write(fs->header.fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry))) return 0; } else #endif { uint16_t fat_entry = HTOL16(FAT16_CLUSTER_LAST_MAX); if(!fs->partition->device_write(fs->header.fat_offset + (offset_t) cluster_num * sizeof(fat_entry), (uint8_t*) &fat_entry, sizeof(fat_entry))) return 0; } /* free remaining clusters */ if(cluster_num_next) return fat_free_clusters(fs, cluster_num_next); else return 1; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Clears a single cluster. * * The complete cluster is filled with zeros. * * \param[in] fs The filesystem on which to operate. * \param[in] cluster_num The cluster to clear. * \returns 0 on failure, 1 on success. */ uint8_t fat_clear_cluster(const struct fat_fs_struct* fs, cluster_t cluster_num) { if(cluster_num < 2) return 0; offset_t cluster_offset = fat_cluster_offset(fs, cluster_num); uint8_t zero[16]; memset(zero, 0, sizeof(zero)); return fs->partition->device_write_interval(cluster_offset, zero, fs->header.cluster_size, fat_clear_cluster_callback, 0 ); } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Callback function for clearing a cluster. */ uintptr_t fat_clear_cluster_callback(uint8_t* buffer, offset_t offset, void* p) { return 16; } #endif /** * \ingroup fat_fs * Calculates the offset of the specified cluster. * * \param[in] fs The filesystem on which to operate. * \param[in] cluster_num The cluster whose offset to calculate. * \returns The cluster offset. */ offset_t fat_cluster_offset(const struct fat_fs_struct* fs, cluster_t cluster_num) { if(!fs || cluster_num < 2) return 0; return fs->header.cluster_zero_offset + (offset_t) (cluster_num - 2) * fs->header.cluster_size; } /** * \ingroup fat_file * Retrieves the directory entry of a path. * * The given path may both describe a file or a directory. * * \param[in] fs The FAT filesystem on which to search. * \param[in] path The path of which to read the directory entry. * \param[out] dir_entry The directory entry to fill. * \returns 0 on failure, 1 on success. * \see fat_read_dir */ uint8_t fat_get_dir_entry_of_path(struct fat_fs_struct* fs, const char* path, struct fat_dir_entry_struct* dir_entry) { if(!fs || !path || path[0] == '\0' || !dir_entry) return 0; if(path[0] == '/') ++path; /* begin with the root directory */ memset(dir_entry, 0, sizeof(*dir_entry)); dir_entry->attributes = FAT_ATTRIB_DIR; while(1) { if(path[0] == '\0') return 1; struct fat_dir_struct* dd = fat_open_dir(fs, dir_entry); if(!dd) break; /* extract the next hierarchy we will search for */ const char* sub_path = strchr(path, '/'); uint8_t length_to_sep; if(sub_path) { length_to_sep = sub_path - path; ++sub_path; } else { length_to_sep = strlen(path); sub_path = path + length_to_sep; } /* read directory entries */ while(fat_read_dir(dd, dir_entry)) { /* check if we have found the next hierarchy */ if((strlen(dir_entry->long_name) != length_to_sep || strncmp(path, dir_entry->long_name, length_to_sep) != 0)) continue; fat_close_dir(dd); dd = 0; if(path[length_to_sep] == '\0') /* we iterated through the whole path and have found the file */ return 1; if(dir_entry->attributes & FAT_ATTRIB_DIR) { /* we found a parent directory of the file we are searching for */ path = sub_path; break; } /* a parent of the file exists, but not the file itself */ return 0; } fat_close_dir(dd); } return 0; } /** * \ingroup fat_file * Opens a file on a FAT filesystem. * * \param[in] fs The filesystem on which the file to open lies. * \param[in] dir_entry The directory entry of the file to open. * \returns The file handle, or 0 on failure. * \see fat_close_file */ struct fat_file_struct* fat_open_file(struct fat_fs_struct* fs, const struct fat_dir_entry_struct* dir_entry) { if(!fs || !dir_entry || (dir_entry->attributes & FAT_ATTRIB_DIR)) return 0; #if USE_DYNAMIC_MEMORY struct fat_file_struct* fd = malloc(sizeof(*fd)); if(!fd) return 0; #else struct fat_file_struct* fd = fat_file_handles; uint8_t i; for(i = 0; i < FAT_FILE_COUNT; ++i) { if(!fd->fs) break; ++fd; } if(i >= FAT_FILE_COUNT) return 0; #endif memcpy(&fd->dir_entry, dir_entry, sizeof(*dir_entry)); fd->fs = fs; fd->pos = 0; fd->pos_cluster = dir_entry->cluster; return fd; } /** * \ingroup fat_file * Closes a file. * * \param[in] fd The file handle of the file to close. * \see fat_open_file */ void fat_close_file(struct fat_file_struct* fd) { if(fd) { #if FAT_DELAY_DIRENTRY_UPDATE /* write directory entry */ fat_write_dir_entry(fd->fs, &fd->dir_entry); #endif #if USE_DYNAMIC_MEMORY free(fd); #else fd->fs = 0; #endif } } /** * \ingroup fat_file * Reads data from a file. * * The data requested is read from the current file location. * * \param[in] fd The file handle of the file from which to read. * \param[out] buffer The buffer into which to write. * \param[in] buffer_len The amount of data to read. * \returns The number of bytes read, 0 on end of file, or -1 on failure. * \see fat_write_file */ intptr_t fat_read_file(struct fat_file_struct* fd, uint8_t* buffer, uintptr_t buffer_len) { /* check arguments */ if(!fd || !buffer || buffer_len < 1) return -1; /* determine number of bytes to read */ if(fd->pos + buffer_len > fd->dir_entry.file_size) buffer_len = fd->dir_entry.file_size - fd->pos; if(buffer_len == 0) return 0; uint16_t cluster_size = fd->fs->header.cluster_size; cluster_t cluster_num = fd->pos_cluster; uintptr_t buffer_left = buffer_len; uint16_t first_cluster_offset = (uint16_t) (fd->pos & (cluster_size - 1)); /* find cluster in which to start reading */ if(!cluster_num) { cluster_num = fd->dir_entry.cluster; if(!cluster_num) { if(!fd->pos) return 0; else return -1; } if(fd->pos) { uint32_t pos = fd->pos; while(pos >= cluster_size) { pos -= cluster_size; cluster_num = fat_get_next_cluster(fd->fs, cluster_num); if(!cluster_num) return -1; } } } /* read data */ do { /* calculate data size to copy from cluster */ offset_t cluster_offset = fat_cluster_offset(fd->fs, cluster_num) + first_cluster_offset; uint16_t copy_length = cluster_size - first_cluster_offset; if(copy_length > buffer_left) copy_length = buffer_left; /* read data */ if(!fd->fs->partition->device_read(cluster_offset, buffer, copy_length)) return buffer_len - buffer_left; /* calculate new file position */ buffer += copy_length; buffer_left -= copy_length; fd->pos += copy_length; if(first_cluster_offset + copy_length >= cluster_size) { /* we are on a cluster boundary, so get the next cluster */ if((cluster_num = fat_get_next_cluster(fd->fs, cluster_num))) { first_cluster_offset = 0; } else { fd->pos_cluster = 0; return buffer_len - buffer_left; } } fd->pos_cluster = cluster_num; } while(buffer_left > 0); /* check if we are done */ return buffer_len; } #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_file * Writes data to a file. * * The data is written to the current file location. * * \param[in] fd The file handle of the file to which to write. * \param[in] buffer The buffer from which to read the data to be written. * \param[in] buffer_len The amount of data to write. * \returns The number of bytes written (0 or something less than \c buffer_len on disk full) or -1 on failure. * \see fat_read_file */ intptr_t fat_write_file(struct fat_file_struct* fd, const uint8_t* buffer, uintptr_t buffer_len) { /* check arguments */ if(!fd || !buffer || buffer_len < 1) return -1; if(fd->pos > fd->dir_entry.file_size) return -1; uint16_t cluster_size = fd->fs->header.cluster_size; cluster_t cluster_num = fd->pos_cluster; uintptr_t buffer_left = buffer_len; uint16_t first_cluster_offset = (uint16_t) (fd->pos & (cluster_size - 1)); /* find cluster in which to start writing */ if(!cluster_num) { cluster_num = fd->dir_entry.cluster; if(!cluster_num) { if(!fd->pos) { /* empty file */ fd->dir_entry.cluster = cluster_num = fat_append_clusters(fd->fs, 0, 1); if(!cluster_num) return 0; } else { return -1; } } if(fd->pos) { uint32_t pos = fd->pos; cluster_t cluster_num_next; while(pos >= cluster_size) { pos -= cluster_size; cluster_num_next = fat_get_next_cluster(fd->fs, cluster_num); if(!cluster_num_next) { if(pos != 0) return -1; /* current file position points beyond end of file */ /* the file exactly ends on a cluster boundary, and we append to it */ cluster_num_next = fat_append_clusters(fd->fs, cluster_num, 1); if(!cluster_num_next) return 0; } cluster_num = cluster_num_next; } } } /* write data */ do { /* calculate data size to write to cluster */ offset_t cluster_offset = fat_cluster_offset(fd->fs, cluster_num) + first_cluster_offset; uint16_t write_length = cluster_size - first_cluster_offset; if(write_length > buffer_left) write_length = buffer_left; /* write data which fits into the current cluster */ if(!fd->fs->partition->device_write(cluster_offset, buffer, write_length)) break; /* calculate new file position */ buffer += write_length; buffer_left -= write_length; fd->pos += write_length; if(first_cluster_offset + write_length >= cluster_size) { /* we are on a cluster boundary, so get the next cluster */ cluster_t cluster_num_next = fat_get_next_cluster(fd->fs, cluster_num); if(!cluster_num_next && buffer_left > 0) /* we reached the last cluster, append a new one */ cluster_num_next = fat_append_clusters(fd->fs, cluster_num, 1); if(!cluster_num_next) { fd->pos_cluster = 0; break; } cluster_num = cluster_num_next; first_cluster_offset = 0; } fd->pos_cluster = cluster_num; } while(buffer_left > 0); /* check if we are done */ /* update directory entry */ if(fd->pos > fd->dir_entry.file_size) { #if !FAT_DELAY_DIRENTRY_UPDATE uint32_t size_old = fd->dir_entry.file_size; #endif /* update file size */ fd->dir_entry.file_size = fd->pos; #if !FAT_DELAY_DIRENTRY_UPDATE /* write directory entry */ if(!fat_write_dir_entry(fd->fs, &fd->dir_entry)) { /* We do not return an error here since we actually wrote * some data to disk. So we calculate the amount of data * we wrote to disk and which lies within the old file size. */ buffer_left = fd->pos - size_old; fd->pos = size_old; } #endif } return buffer_len - buffer_left; } #endif /** * \ingroup fat_file * Repositions the read/write file offset. * * Changes the file offset where the next call to fat_read_file() * or fat_write_file() starts reading/writing. * * If the new offset is beyond the end of the file, fat_resize_file() * is implicitly called, i.e. the file is expanded. * * The new offset can be given in different ways determined by * the \c whence parameter: * - \b FAT_SEEK_SET: \c *offset is relative to the beginning of the file. * - \b FAT_SEEK_CUR: \c *offset is relative to the current file position. * - \b FAT_SEEK_END: \c *offset is relative to the end of the file. * * The resulting absolute offset is written to the location the \c offset * parameter points to. * * Calling this function can also be used to retrieve the current file position: \code int32_t file_pos = 0; if(!fat_seek_file(fd, &file_pos, FAT_SEEK_CUR)) { // error } // file_pos now contains the absolute file position \endcode * * \param[in] fd The file decriptor of the file on which to seek. * \param[in,out] offset A pointer to the new offset, as affected by the \c whence * parameter. The function writes the new absolute offset * to this location before it returns. * \param[in] whence Affects the way \c offset is interpreted, see above. * \returns 0 on failure, 1 on success. */ uint8_t fat_seek_file(struct fat_file_struct* fd, int32_t* offset, uint8_t whence) { if(!fd || !offset) return 0; uint32_t new_pos = fd->pos; switch(whence) { case FAT_SEEK_SET: new_pos = *offset; break; case FAT_SEEK_CUR: new_pos += *offset; break; case FAT_SEEK_END: new_pos = fd->dir_entry.file_size + *offset; break; default: return 0; } if(new_pos > fd->dir_entry.file_size #if FAT_WRITE_SUPPORT && !fat_resize_file(fd, new_pos) #endif ) return 0; fd->pos = new_pos; fd->pos_cluster = 0; *offset = (int32_t) new_pos; return 1; } #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_file * Resizes a file to have a specific size. * * Enlarges or shrinks the file pointed to by the file descriptor to have * exactly the specified size. * * If the file is truncated, all bytes having an equal or larger offset * than the given size are lost. If the file is expanded, the additional * bytes are allocated. * * \note Please be aware that this function just allocates or deallocates disk * space, it does not explicitely clear it. To avoid data leakage, this * must be done manually. * * \param[in] fd The file decriptor of the file which to resize. * \param[in] size The new size of the file. * \returns 0 on failure, 1 on success. */ uint8_t fat_resize_file(struct fat_file_struct* fd, uint32_t size) { if(!fd) return 0; cluster_t cluster_num = fd->dir_entry.cluster; uint16_t cluster_size = fd->fs->header.cluster_size; uint32_t size_new = size; do { if(cluster_num == 0 && size_new == 0) /* the file stays empty */ break; /* seek to the next cluster as long as we need the space */ while(size_new > cluster_size) { /* get next cluster of file */ cluster_t cluster_num_next = fat_get_next_cluster(fd->fs, cluster_num); if(cluster_num_next) { cluster_num = cluster_num_next; size_new -= cluster_size; } else { break; } } if(size_new > cluster_size || cluster_num == 0) { /* Allocate new cluster chain and append * it to the existing one, if available. */ cluster_t cluster_count = (size_new + cluster_size - 1) / cluster_size; cluster_t cluster_new_chain = fat_append_clusters(fd->fs, cluster_num, cluster_count); if(!cluster_new_chain) return 0; if(!cluster_num) { cluster_num = cluster_new_chain; fd->dir_entry.cluster = cluster_num; } } /* write new directory entry */ fd->dir_entry.file_size = size; if(size == 0) fd->dir_entry.cluster = 0; if(!fat_write_dir_entry(fd->fs, &fd->dir_entry)) return 0; if(size == 0) { /* free all clusters of file */ fat_free_clusters(fd->fs, cluster_num); } else if(size_new <= cluster_size) { /* free all clusters no longer needed */ fat_terminate_clusters(fd->fs, cluster_num); } } while(0); /* correct file position */ if(size < fd->pos) { fd->pos = size; fd->pos_cluster = 0; } return 1; } #endif /** * \ingroup fat_dir * Opens a directory. * * \param[in] fs The filesystem on which the directory to open resides. * \param[in] dir_entry The directory entry which stands for the directory to open. * \returns An opaque directory descriptor on success, 0 on failure. * \see fat_close_dir */ struct fat_dir_struct* fat_open_dir(struct fat_fs_struct* fs, const struct fat_dir_entry_struct* dir_entry) { if(!fs || !dir_entry || !(dir_entry->attributes & FAT_ATTRIB_DIR)) return 0; #if USE_DYNAMIC_MEMORY struct fat_dir_struct* dd = malloc(sizeof(*dd)); if(!dd) return 0; #else struct fat_dir_struct* dd = fat_dir_handles; uint8_t i; for(i = 0; i < FAT_DIR_COUNT; ++i) { if(!dd->fs) break; ++dd; } if(i >= FAT_DIR_COUNT) return 0; #endif memcpy(&dd->dir_entry, dir_entry, sizeof(*dir_entry)); dd->fs = fs; dd->entry_cluster = dir_entry->cluster; dd->entry_offset = 0; return dd; } /** * \ingroup fat_dir * Closes a directory descriptor. * * This function destroys a directory descriptor which was * previously obtained by calling fat_open_dir(). When this * function returns, the given descriptor will be invalid. * * \param[in] dd The directory descriptor to close. * \see fat_open_dir */ void fat_close_dir(struct fat_dir_struct* dd) { if(dd) #if USE_DYNAMIC_MEMORY free(dd); #else dd->fs = 0; #endif } /** * \ingroup fat_dir * Reads the next directory entry contained within a parent directory. * * \param[in] dd The descriptor of the parent directory from which to read the entry. * \param[out] dir_entry Pointer to a buffer into which to write the directory entry information. * \returns 0 on failure, 1 on success. * \see fat_reset_dir */ uint8_t fat_read_dir(struct fat_dir_struct* dd, struct fat_dir_entry_struct* dir_entry) { if(!dd || !dir_entry) return 0; /* get current position of directory handle */ struct fat_fs_struct* fs = dd->fs; const struct fat_header_struct* header = &fs->header; uint16_t cluster_size = header->cluster_size; cluster_t cluster_num = dd->entry_cluster; uint16_t cluster_offset = dd->entry_offset; struct fat_read_dir_callback_arg arg; if(cluster_offset >= cluster_size) { /* The latest call hit the border of the last cluster in * the chain, but it still returned a directory entry. * So we now reset the handle and signal the caller the * end of the listing. */ fat_reset_dir(dd); return 0; } /* reset callback arguments */ memset(&arg, 0, sizeof(arg)); memset(dir_entry, 0, sizeof(*dir_entry)); arg.dir_entry = dir_entry; /* check if we read from the root directory */ if(cluster_num == 0) { #if FAT_FAT32_SUPPORT if(fs->partition->type == PARTITION_TYPE_FAT32) cluster_num = header->root_dir_cluster; else #endif cluster_size = header->cluster_zero_offset - header->root_dir_offset; } /* read entries */ uint8_t buffer[32]; while(!arg.finished) { /* read directory entries up to the cluster border */ uint16_t cluster_left = cluster_size - cluster_offset; offset_t pos = cluster_offset; if(cluster_num == 0) pos += header->root_dir_offset; else pos += fat_cluster_offset(fs, cluster_num); arg.bytes_read = 0; if(!fs->partition->device_read_interval(pos, buffer, sizeof(buffer), cluster_left, fat_dir_entry_read_callback, &arg) ) return 0; cluster_offset += arg.bytes_read; if(cluster_offset >= cluster_size) { /* we reached the cluster border and switch to the next cluster */ /* get number of next cluster */ if((cluster_num = fat_get_next_cluster(fs, cluster_num)) != 0) { cluster_offset = 0; continue; } /* we are at the end of the cluster chain */ if(!arg.finished) { /* directory entry not found, reset directory handle */ fat_reset_dir(dd); return 0; } else { /* The current execution of the function has been successful, * so we can not signal an end of the directory listing to * the caller, but must wait for the next call. So we keep an * invalid cluster offset to mark this directory handle's * traversal as finished. */ } break; } } dd->entry_cluster = cluster_num; dd->entry_offset = cluster_offset; return arg.finished; } /** * \ingroup fat_dir * Resets a directory handle. * * Resets the directory handle such that reading restarts * with the first directory entry. * * \param[in] dd The directory handle to reset. * \returns 0 on failure, 1 on success. * \see fat_read_dir */ uint8_t fat_reset_dir(struct fat_dir_struct* dd) { if(!dd) return 0; dd->entry_cluster = dd->dir_entry.cluster; dd->entry_offset = 0; return 1; } /** * \ingroup fat_fs * Callback function for reading a directory entry. * * Interprets a raw directory entry and puts the contained * information into a fat_dir_entry_struct structure. * * For a single file there may exist multiple directory * entries. All except the last one are lfn entries, which * contain parts of the long filename. The last directory * entry is a traditional 8.3 style one. It contains all * other information like size, cluster, date and time. * * \param[in] buffer A pointer to 32 bytes of raw data. * \param[in] offset The absolute offset of the raw data. * \param[in,out] p An argument structure controlling operation. * \returns 0 on failure or completion, 1 if reading has * to be continued */ uint8_t fat_dir_entry_read_callback(uint8_t* buffer, offset_t offset, void* p) { struct fat_read_dir_callback_arg* arg = p; struct fat_dir_entry_struct* dir_entry = arg->dir_entry; arg->bytes_read += 32; /* skip deleted or empty entries */ if(buffer[0] == FAT_DIRENTRY_DELETED || !buffer[0]) { #if FAT_LFN_SUPPORT arg->checksum = 0; #endif return 1; } #if !FAT_LFN_SUPPORT /* skip lfn entries */ if(buffer[11] == 0x0f) return 1; #endif char* long_name = dir_entry->long_name; #if FAT_LFN_SUPPORT if(buffer[11] == 0x0f) { /* checksum validation */ if(arg->checksum == 0 || arg->checksum != buffer[13]) { /* reset directory entry */ memset(dir_entry, 0, sizeof(*dir_entry)); arg->checksum = buffer[13]; dir_entry->entry_offset = offset; } /* lfn supports unicode, but we do not, for now. * So we assume pure ascii and read only every * second byte. */ uint16_t char_offset = ((buffer[0] & 0x3f) - 1) * 13; const uint8_t char_mapping[] = { 1, 3, 5, 7, 9, 14, 16, 18, 20, 22, 24, 28, 30 }; for(uint8_t i = 0; i <= 12 && char_offset + i < sizeof(dir_entry->long_name) - 1; ++i) long_name[char_offset + i] = buffer[char_mapping[i]]; return 1; } else #endif { #if FAT_LFN_SUPPORT /* if we do not have a long name or the previous lfn does not match, take the 8.3 name */ if(long_name[0] == '\0' || arg->checksum != fat_calc_83_checksum(buffer)) #endif { /* reset directory entry */ memset(dir_entry, 0, sizeof(*dir_entry)); dir_entry->entry_offset = offset; uint8_t i; for(i = 0; i < 8; ++i) { if(buffer[i] == ' ') break; long_name[i] = buffer[i]; /* Windows NT and later versions do not store lfn entries * for 8.3 names which have a lowercase basename, extension * or both when everything else is uppercase. They use two * extra bits to signal a lowercase basename or extension. */ if((buffer[12] & 0x08) && buffer[i] >= 'A' && buffer[i] <= 'Z') long_name[i] += 'a' - 'A'; } if(long_name[0] == 0x05) long_name[0] = (char) FAT_DIRENTRY_DELETED; if(buffer[8] != ' ') { long_name[i++] = '.'; uint8_t j = 8; for(; j < 11; ++j) { if(buffer[j] == ' ') break; long_name[i] = buffer[j]; /* See above for the lowercase 8.3 name handling of * Windows NT and later. */ if((buffer[12] & 0x10) && buffer[j] >= 'A' && buffer[j] <= 'Z') long_name[i] += 'a' - 'A'; ++i; } } long_name[i] = '\0'; } /* extract properties of file and store them within the structure */ dir_entry->attributes = buffer[11]; dir_entry->cluster = read16(&buffer[26]); #if FAT_FAT32_SUPPORT dir_entry->cluster |= ((cluster_t) read16(&buffer[20])) << 16; #endif dir_entry->file_size = read32(&buffer[28]); #if FAT_DATETIME_SUPPORT dir_entry->modification_time = read16(&buffer[22]); dir_entry->modification_date = read16(&buffer[24]); #endif arg->finished = 1; return 0; } } #if DOXYGEN || FAT_LFN_SUPPORT /** * \ingroup fat_fs * Calculates the checksum for 8.3 names used within the * corresponding lfn directory entries. * * \param[in] file_name_83 The 11-byte file name buffer. * \returns The checksum of the given file name. */ uint8_t fat_calc_83_checksum(const uint8_t* file_name_83) { uint8_t checksum = file_name_83[0]; for(uint8_t i = 1; i < 11; ++i) checksum = ((checksum >> 1) | (checksum << 7)) + file_name_83[i]; return checksum; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Searches for space where to store a directory entry. * * \param[in] fs The filesystem on which to operate. * \param[in] parent The directory in which to search. * \param[in] dir_entry The directory entry for which to search space. * \returns 0 on failure, a device offset on success. */ offset_t fat_find_offset_for_dir_entry(struct fat_fs_struct* fs, const struct fat_dir_struct* parent, const struct fat_dir_entry_struct* dir_entry) { if(!fs || !dir_entry) return 0; /* search for a place where to write the directory entry to disk */ #if FAT_LFN_SUPPORT uint8_t free_dir_entries_needed = (strlen(dir_entry->long_name) + 12) / 13 + 1; uint8_t free_dir_entries_found = 0; #endif cluster_t cluster_num = parent->dir_entry.cluster; offset_t dir_entry_offset = 0; offset_t offset = 0; offset_t offset_to = 0; #if FAT_FAT32_SUPPORT uint8_t is_fat32 = (fs->partition->type == PARTITION_TYPE_FAT32); #endif if(cluster_num == 0) { #if FAT_FAT32_SUPPORT if(is_fat32) { cluster_num = fs->header.root_dir_cluster; } else #endif { /* we read/write from the root directory entry */ offset = fs->header.root_dir_offset; offset_to = fs->header.cluster_zero_offset; dir_entry_offset = offset; } } while(1) { if(offset == offset_to) { if(cluster_num == 0) /* We iterated through the whole root directory and * could not find enough space for the directory entry. */ return 0; if(offset) { /* We reached a cluster boundary and have to * switch to the next cluster. */ cluster_t cluster_next = fat_get_next_cluster(fs, cluster_num); if(!cluster_next) { cluster_next = fat_append_clusters(fs, cluster_num, 1); if(!cluster_next) return 0; /* we appended a new cluster and know it is free */ dir_entry_offset = fs->header.cluster_zero_offset + (offset_t) (cluster_next - 2) * fs->header.cluster_size; /* clear cluster to avoid garbage directory entries */ fat_clear_cluster(fs, cluster_next); break; } cluster_num = cluster_next; } offset = fat_cluster_offset(fs, cluster_num); offset_to = offset + fs->header.cluster_size; dir_entry_offset = offset; #if FAT_LFN_SUPPORT free_dir_entries_found = 0; #endif } /* read next lfn or 8.3 entry */ uint8_t first_char; if(!fs->partition->device_read(offset, &first_char, sizeof(first_char))) return 0; /* check if we found a free directory entry */ if(first_char == FAT_DIRENTRY_DELETED || !first_char) { /* check if we have the needed number of available entries */ #if FAT_LFN_SUPPORT ++free_dir_entries_found; if(free_dir_entries_found >= free_dir_entries_needed) #endif break; offset += 32; } else { offset += 32; dir_entry_offset = offset; #if FAT_LFN_SUPPORT free_dir_entries_found = 0; #endif } } return dir_entry_offset; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_fs * Writes a directory entry to disk. * * \note The file name is not checked for invalid characters. * * \note The generation of the short 8.3 file name is quite * simple. The first eight characters are used for the filename. * The extension, if any, is made up of the first three characters * following the last dot within the long filename. If the * filename (without the extension) is longer than eight characters, * the lower byte of the cluster number replaces the last two * characters to avoid name clashes. In any other case, it is your * responsibility to avoid name clashes. * * \param[in] fs The filesystem on which to operate. * \param[in] dir_entry The directory entry to write. * \returns 0 on failure, 1 on success. */ uint8_t fat_write_dir_entry(const struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry) { if(!fs || !dir_entry) return 0; #if FAT_DATETIME_SUPPORT { uint16_t year; uint8_t month; uint8_t day; uint8_t hour; uint8_t min; uint8_t sec; fat_get_datetime(&year, &month, &day, &hour, &min, &sec); fat_set_file_modification_date(dir_entry, year, month, day); fat_set_file_modification_time(dir_entry, hour, min, sec); } #endif device_write_t device_write = fs->partition->device_write; offset_t offset = dir_entry->entry_offset; const char* name = dir_entry->long_name; uint8_t name_len = strlen(name); #if FAT_LFN_SUPPORT uint8_t lfn_entry_count = (name_len + 12) / 13; #endif uint8_t buffer[32]; /* write 8.3 entry */ /* generate 8.3 file name */ memset(&buffer[0], ' ', 11); char* name_ext = strrchr(name, '.'); if(name_ext && *++name_ext) { uint8_t name_ext_len = strlen(name_ext); name_len -= name_ext_len + 1; if(name_ext_len > 3) #if FAT_LFN_SUPPORT name_ext_len = 3; #else return 0; #endif memcpy(&buffer[8], name_ext, name_ext_len); } if(name_len <= 8) { memcpy(buffer, name, name_len); #if FAT_LFN_SUPPORT /* For now, we create lfn entries for all files, * except the "." and ".." directory references. * This is to avoid difficulties with capitalization, * as 8.3 filenames allow uppercase letters only. * * Theoretically it would be possible to leave * the 8.3 entry alone if the basename and the * extension have no mixed capitalization. */ if(name[0] == '.' && ((name[1] == '.' && name[2] == '\0') || name[1] == '\0') ) lfn_entry_count = 0; #endif } else { #if FAT_LFN_SUPPORT memcpy(buffer, name, 8); /* Minimize 8.3 name clashes by appending * the lower byte of the cluster number. */ uint8_t num = dir_entry->cluster & 0xff; buffer[6] = (num < 0xa0) ? ('0' + (num >> 4)) : ('a' + (num >> 4)); num &= 0x0f; buffer[7] = (num < 0x0a) ? ('0' + num) : ('a' + num); #else return 0; #endif } if(buffer[0] == FAT_DIRENTRY_DELETED) buffer[0] = 0x05; /* fill directory entry buffer */ memset(&buffer[11], 0, sizeof(buffer) - 11); buffer[0x0b] = dir_entry->attributes; #if FAT_DATETIME_SUPPORT write16(&buffer[0x16], dir_entry->modification_time); write16(&buffer[0x18], dir_entry->modification_date); #endif #if FAT_FAT32_SUPPORT write16(&buffer[0x14], (uint16_t) (dir_entry->cluster >> 16)); #endif write16(&buffer[0x1a], dir_entry->cluster); write32(&buffer[0x1c], dir_entry->file_size); /* write to disk */ #if FAT_LFN_SUPPORT if(!device_write(offset + (uint16_t) lfn_entry_count * 32, buffer, sizeof(buffer))) #else if(!device_write(offset, buffer, sizeof(buffer))) #endif return 0; #if FAT_LFN_SUPPORT /* calculate checksum of 8.3 name */ uint8_t checksum = fat_calc_83_checksum(buffer); /* write lfn entries */ for(uint8_t lfn_entry = lfn_entry_count; lfn_entry > 0; --lfn_entry) { memset(buffer, 0xff, sizeof(buffer)); /* set file name */ const char* long_name_curr = name + (lfn_entry - 1) * 13; uint8_t i = 1; while(i < 0x1f) { buffer[i++] = *long_name_curr; buffer[i++] = 0; switch(i) { case 0x0b: i = 0x0e; break; case 0x1a: i = 0x1c; break; } if(!*long_name_curr++) break; } /* set index of lfn entry */ buffer[0x00] = lfn_entry; if(lfn_entry == lfn_entry_count) buffer[0x00] |= FAT_DIRENTRY_LFNLAST; /* mark as lfn entry */ buffer[0x0b] = 0x0f; /* set 8.3 checksum */ buffer[0x0d] = checksum; /* clear reserved bytes */ buffer[0x0c] = 0; buffer[0x1a] = 0; buffer[0x1b] = 0; /* write entry */ device_write(offset, buffer, sizeof(buffer)); offset += sizeof(buffer); } #endif return 1; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_file * Creates a file. * * Creates a file and obtains the directory entry of the * new file. If the file to create already exists, the * directory entry of the existing file will be returned * within the dir_entry parameter. * * \note The file name is not checked for invalid characters. * * \note The generation of the short 8.3 file name is quite * simple. The first eight characters are used for the filename. * The extension, if any, is made up of the first three characters * following the last dot within the long filename. If the * filename (without the extension) is longer than eight characters, * the lower byte of the cluster number replaces the last two * characters to avoid name clashes. In any other case, it is your * responsibility to avoid name clashes. * * \param[in] parent The handle of the directory in which to create the file. * \param[in] file The name of the file to create. * \param[out] dir_entry The directory entry to fill for the new (or existing) file. * \returns 0 on failure, 1 on success, 2 if the file already existed. * \see fat_delete_file */ uint8_t fat_create_file(struct fat_dir_struct* parent, const char* file, struct fat_dir_entry_struct* dir_entry) { if(!parent || !file || !file[0] || !dir_entry) return 0; /* check if the file already exists */ while(1) { if(!fat_read_dir(parent, dir_entry)) break; if(strcmp(file, dir_entry->long_name) == 0) { fat_reset_dir(parent); return 2; } } struct fat_fs_struct* fs = parent->fs; /* prepare directory entry with values already known */ memset(dir_entry, 0, sizeof(*dir_entry)); strncpy(dir_entry->long_name, file, sizeof(dir_entry->long_name) - 1); /* find place where to store directory entry */ if(!(dir_entry->entry_offset = fat_find_offset_for_dir_entry(fs, parent, dir_entry))) return 0; /* write directory entry to disk */ if(!fat_write_dir_entry(fs, dir_entry)) return 0; return 1; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_file * Deletes a file or directory. * * If a directory is deleted without first deleting its * subdirectories and files, disk space occupied by these * files will get wasted as there is no chance to release * it and mark it as free. * * \param[in] fs The filesystem on which to operate. * \param[in] dir_entry The directory entry of the file to delete. * \returns 0 on failure, 1 on success. * \see fat_create_file */ uint8_t fat_delete_file(struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry) { if(!fs || !dir_entry) return 0; /* get offset of the file's directory entry */ offset_t dir_entry_offset = dir_entry->entry_offset; if(!dir_entry_offset) return 0; #if FAT_LFN_SUPPORT uint8_t buffer[12]; while(1) { /* read directory entry */ if(!fs->partition->device_read(dir_entry_offset, buffer, sizeof(buffer))) return 0; /* mark the directory entry as deleted */ buffer[0] = FAT_DIRENTRY_DELETED; /* write back entry */ if(!fs->partition->device_write(dir_entry_offset, buffer, sizeof(buffer))) return 0; /* check if we deleted the whole entry */ if(buffer[11] != 0x0f) break; dir_entry_offset += 32; } #else /* mark the directory entry as deleted */ uint8_t first_char = FAT_DIRENTRY_DELETED; if(!fs->partition->device_write(dir_entry_offset, &first_char, 1)) return 0; #endif /* We deleted the directory entry. The next thing to do is * marking all occupied clusters as free. */ return (dir_entry->cluster == 0 || fat_free_clusters(fs, dir_entry->cluster)); } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_file * Moves or renames a file. * * Changes a file's name, optionally moving it into another * directory as well. Before calling this function, the * target file name must not exist. Moving a file to a * different filesystem (i.e. \a parent_new doesn't lie on * \a fs) is not supported. * * After successfully renaming (and moving) the file, the * given directory entry is updated such that it points to * the file's new location. * * \note The notes which apply to fat_create_file() also * apply to this function. * * \param[in] fs The filesystem on which to operate. * \param[in,out] dir_entry The directory entry of the file to move. * \param[in] parent_new The handle of the new parent directory of the file. * \param[in] file_new The file's new name. * \returns 0 on failure, 1 on success. * \see fat_create_file, fat_delete_file, fat_move_dir */ uint8_t fat_move_file(struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry, struct fat_dir_struct* parent_new, const char* file_new) { if(!fs || !dir_entry || !parent_new || (file_new && !file_new[0])) return 0; if(fs != parent_new->fs) return 0; /* use existing file name if none has been specified */ if(!file_new) file_new = dir_entry->long_name; /* create file with new file name */ struct fat_dir_entry_struct dir_entry_new; if(!fat_create_file(parent_new, file_new, &dir_entry_new)) return 0; /* copy members of directory entry which do not change with rename */ dir_entry_new.attributes = dir_entry->attributes; #if FAT_DATETIME_SUPPORT dir_entry_new.modification_time = dir_entry->modification_time; dir_entry_new.modification_date = dir_entry->modification_date; #endif dir_entry_new.cluster = dir_entry->cluster; dir_entry_new.file_size = dir_entry->file_size; /* make the new file name point to the old file's content */ if(!fat_write_dir_entry(fs, &dir_entry_new)) { fat_delete_file(fs, &dir_entry_new); return 0; } /* delete the old file, but not its clusters, which have already been remapped above */ dir_entry->cluster = 0; if(!fat_delete_file(fs, dir_entry)) return 0; *dir_entry = dir_entry_new; return 1; } #endif #if DOXYGEN || FAT_WRITE_SUPPORT /** * \ingroup fat_dir * Creates a directory. * * Creates a directory and obtains its directory entry. * If the directory to create already exists, its * directory entry will be returned within the dir_entry * parameter. * * \note The notes which apply to fat_create_file() also * apply to this function. * * \param[in] parent The handle of the parent directory of the new directory. * \param[in] dir The name of the directory to create. * \param[out] dir_entry The directory entry to fill for the new directory. * \returns 0 on failure, 1 on success. * \see fat_delete_dir */ uint8_t fat_create_dir(struct fat_dir_struct* parent, const char* dir, struct fat_dir_entry_struct* dir_entry) { if(!parent || !dir || !dir[0] || !dir_entry) return 0; /* check if the file or directory already exists */ while(fat_read_dir(parent, dir_entry)) { if(strcmp(dir, dir_entry->long_name) == 0) { fat_reset_dir(parent); return 0; } } struct fat_fs_struct* fs = parent->fs; /* allocate cluster which will hold directory entries */ cluster_t dir_cluster = fat_append_clusters(fs, 0, 1); if(!dir_cluster) return 0; /* clear cluster to prevent bogus directory entries */ fat_clear_cluster(fs, dir_cluster); memset(dir_entry, 0, sizeof(*dir_entry)); dir_entry->attributes = FAT_ATTRIB_DIR; /* create "." directory self reference */ dir_entry->entry_offset = fs->header.cluster_zero_offset + (offset_t) (dir_cluster - 2) * fs->header.cluster_size; dir_entry->long_name[0] = '.'; dir_entry->cluster = dir_cluster; if(!fat_write_dir_entry(fs, dir_entry)) { fat_free_clusters(fs, dir_cluster); return 0; } /* create ".." parent directory reference */ dir_entry->entry_offset += 32; dir_entry->long_name[1] = '.'; dir_entry->cluster = parent->dir_entry.cluster; if(!fat_write_dir_entry(fs, dir_entry)) { fat_free_clusters(fs, dir_cluster); return 0; } /* fill directory entry */ strncpy(dir_entry->long_name, dir, sizeof(dir_entry->long_name) - 1); dir_entry->cluster = dir_cluster; /* find place where to store directory entry */ if(!(dir_entry->entry_offset = fat_find_offset_for_dir_entry(fs, parent, dir_entry))) { fat_free_clusters(fs, dir_cluster); return 0; } /* write directory to disk */ if(!fat_write_dir_entry(fs, dir_entry)) { fat_free_clusters(fs, dir_cluster); return 0; } return 1; } #endif /** * \ingroup fat_dir * Deletes a directory. * * This is just a synonym for fat_delete_file(). * If a directory is deleted without first deleting its * subdirectories and files, disk space occupied by these * files will get wasted as there is no chance to release * it and mark it as free. * * \param[in] fs The filesystem on which to operate. * \param[in] dir_entry The directory entry of the directory to delete. * \returns 0 on failure, 1 on success. * \see fat_create_dir */ #ifdef DOXYGEN uint8_t fat_delete_dir(struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry); #endif /** * \ingroup fat_dir * Moves or renames a directory. * * This is just a synonym for fat_move_file(). * * \param[in] fs The filesystem on which to operate. * \param[in,out] dir_entry The directory entry of the directory to move. * \param[in] parent_new The handle of the new parent directory. * \param[in] dir_new The directory's new name. * \returns 0 on failure, 1 on success. * \see fat_create_dir, fat_delete_dir, fat_move_file */ #ifdef DOXYGEN uint8_t fat_move_dir(struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry, struct fat_dir_struct* parent_new, const char* dir_new); #endif #if DOXYGEN || FAT_DATETIME_SUPPORT /** * \ingroup fat_file * Returns the modification date of a file. * * \param[in] dir_entry The directory entry of which to return the modification date. * \param[out] year The year the file was last modified. * \param[out] month The month the file was last modified. * \param[out] day The day the file was last modified. */ void fat_get_file_modification_date(const struct fat_dir_entry_struct* dir_entry, uint16_t* year, uint8_t* month, uint8_t* day) { if(!dir_entry) return; *year = 1980 + ((dir_entry->modification_date >> 9) & 0x7f); *month = (dir_entry->modification_date >> 5) & 0x0f; *day = (dir_entry->modification_date >> 0) & 0x1f; } #endif #if DOXYGEN || FAT_DATETIME_SUPPORT /** * \ingroup fat_file * Returns the modification time of a file. * * \param[in] dir_entry The directory entry of which to return the modification time. * \param[out] hour The hour the file was last modified. * \param[out] min The min the file was last modified. * \param[out] sec The sec the file was last modified. */ void fat_get_file_modification_time(const struct fat_dir_entry_struct* dir_entry, uint8_t* hour, uint8_t* min, uint8_t* sec) { if(!dir_entry) return; *hour = (dir_entry->modification_time >> 11) & 0x1f; *min = (dir_entry->modification_time >> 5) & 0x3f; *sec = ((dir_entry->modification_time >> 0) & 0x1f) * 2; } #endif #if DOXYGEN || (FAT_WRITE_SUPPORT && FAT_DATETIME_SUPPORT) /** * \ingroup fat_file * Sets the modification time of a date. * * \param[in] dir_entry The directory entry for which to set the modification date. * \param[in] year The year the file was last modified. * \param[in] month The month the file was last modified. * \param[in] day The day the file was last modified. */ void fat_set_file_modification_date(struct fat_dir_entry_struct* dir_entry, uint16_t year, uint8_t month, uint8_t day) { if(!dir_entry) return; dir_entry->modification_date = ((year - 1980) << 9) | ((uint16_t) month << 5) | ((uint16_t) day << 0); } #endif #if DOXYGEN || (FAT_WRITE_SUPPORT && FAT_DATETIME_SUPPORT) /** * \ingroup fat_file * Sets the modification time of a file. * * \param[in] dir_entry The directory entry for which to set the modification time. * \param[in] hour The year the file was last modified. * \param[in] min The month the file was last modified. * \param[in] sec The day the file was last modified. */ void fat_set_file_modification_time(struct fat_dir_entry_struct* dir_entry, uint8_t hour, uint8_t min, uint8_t sec) { if(!dir_entry) return; dir_entry->modification_time = ((uint16_t) hour << 11) | ((uint16_t) min << 5) | ((uint16_t) sec >> 1) ; } #endif /** * \ingroup fat_fs * Returns the amount of total storage capacity of the filesystem in bytes. * * \param[in] fs The filesystem on which to operate. * \returns 0 on failure, the filesystem size in bytes otherwise. */ offset_t fat_get_fs_size(const struct fat_fs_struct* fs) { if(!fs) return 0; #if FAT_FAT32_SUPPORT if(fs->partition->type == PARTITION_TYPE_FAT32) return (offset_t) (fs->header.fat_size / 4 - 2) * fs->header.cluster_size; else #endif return (offset_t) (fs->header.fat_size / 2 - 2) * fs->header.cluster_size; } /** * \ingroup fat_fs * Returns the amount of free storage capacity on the filesystem in bytes. * * \note As the FAT filesystem is cluster based, this function does not * return continuous values but multiples of the cluster size. * * \param[in] fs The filesystem on which to operate. * \returns 0 on failure, the free filesystem space in bytes otherwise. */ offset_t fat_get_fs_free(const struct fat_fs_struct* fs) { if(!fs) return 0; uint8_t fat[32]; struct fat_usage_count_callback_arg count_arg; count_arg.cluster_count = 0; count_arg.buffer_size = sizeof(fat); offset_t fat_offset = fs->header.fat_offset; uint32_t fat_size = fs->header.fat_size; while(fat_size > 0) { uintptr_t length = UINTPTR_MAX - 1; if(fat_size < length) length = fat_size; if(!fs->partition->device_read_interval(fat_offset, fat, sizeof(fat), length, #if FAT_FAT32_SUPPORT (fs->partition->type == PARTITION_TYPE_FAT16) ? fat_get_fs_free_16_callback : fat_get_fs_free_32_callback, #else fat_get_fs_free_16_callback, #endif &count_arg ) ) return 0; fat_offset += length; fat_size -= length; } return (offset_t) count_arg.cluster_count * fs->header.cluster_size; } /** * \ingroup fat_fs * Callback function used for counting free clusters in a FAT. */ uint8_t fat_get_fs_free_16_callback(uint8_t* buffer, offset_t offset, void* p) { struct fat_usage_count_callback_arg* count_arg = (struct fat_usage_count_callback_arg*) p; uintptr_t buffer_size = count_arg->buffer_size; for(uintptr_t i = 0; i < buffer_size; i += 2, buffer += 2) { uint16_t cluster = read16(buffer); if(cluster == HTOL16(FAT16_CLUSTER_FREE)) ++(count_arg->cluster_count); } return 1; } #if DOXYGEN || FAT_FAT32_SUPPORT /** * \ingroup fat_fs * Callback function used for counting free clusters in a FAT32. */ uint8_t fat_get_fs_free_32_callback(uint8_t* buffer, offset_t offset, void* p) { struct fat_usage_count_callback_arg* count_arg = (struct fat_usage_count_callback_arg*) p; uintptr_t buffer_size = count_arg->buffer_size; for(uintptr_t i = 0; i < buffer_size; i += 4, buffer += 4) { uint32_t cluster = read32(buffer); if(cluster == HTOL32(FAT32_CLUSTER_FREE)) ++(count_arg->cluster_count); } return 1; } #endif