fatfs: initial implementation

kernel-src/include/kernel/fatfs.h

@@ -0,0 +1,115 @@
+#ifndef _FATFS_H
+#define _FATFS_H
+
+#include <kernel/vfs.h>
+#include <hashtable.h>
+
+#define FATFS_FAT12 1
+#define FATFS_FAT16 2
+#define FATFS_FAT32 3
+
+#define FATFS_CLUSTER_IS_EOF_FAT12(x) ((x) >= 0xff8)
+#define FATFS_CLUSTER_IS_EOF_FAT16(x) ((x) >= 0xfff8)
+#define FATFS_CLUSTER_IS_EOF_FAT32(x) (((x) & 0x0fffffff) >= 0x0ffffff8)
+
+#define FATFS_CLUSTER_FREE 0
+
+#define FATFS_CLUSTER_EOF_FAT12 0xfff
+#define FATFS_CLUSTER_EOF_FAT16 0xffff
+#define FATFS_CLUSTER_EOF_FAT32 0xfffffff
+
+#define FATFS_DENT_ATTRIBUTE_READ_ONLY 1
+#define FATFS_DENT_ATTRIBUTE_HIDDEN 2
+#define FATFS_DENT_ATTRIBUTE_SYSTEM 4
+#define FATFS_DENT_ATTRIBUTE_VOLUME_ID 8
+#define FATFS_DENT_ATTRIBUTE_DIRECTORY 16
+#define FATFS_DENT_ATTRIBUTE_ARCHIVE 32
+
+typedef struct {
+	char short_name[11];
+	uint8_t attributes;
+	uint8_t reserved;
+	uint8_t creation_tenth;
+	uint16_t creation_time; // 2 second unit
+	uint16_t creation_date;
+	uint16_t access_date;
+	uint16_t cluster_high;
+	uint16_t write_time; // 2 second unit
+	uint16_t write_date;
+	uint16_t cluster_low;
+	uint32_t file_size_bytes;
+} __attribute__((packed)) fatfs_dent_t;
+
+typedef struct {
+	uint8_t order;
+	uint16_t name1[5];
+	uint8_t attr;
+	uint8_t reserved;
+	uint8_t checksum;
+	uint16_t name2[6];
+	uint16_t zero;
+	uint16_t name3[2];
+} __attribute__((packed)) fatfs_lfn_dent_t;
+
+typedef uint32_t fatfs_cluster_t;
+
+typedef struct fatnode_t {
+	vnode_t vnode;
+	fatfs_cluster_t cluster;
+
+	size_t size;
+
+	struct fatnode_t *parent_dir;
+	size_t dent_disk_offset;
+} fatnode_t;
+
+typedef struct {
+	vfs_t vfs;
+	vnode_t *backing;
+	int type;
+
+	union {
+		fatfs_cluster_t root_cluster;
+		struct {
+			size_t root_offset;
+			size_t root_entry_count;
+		};
+	};
+
+	size_t fat_offset;
+	size_t data_offset;
+
+	size_t cluster_size;
+	size_t cluster_count;
+
+	mutex_t fat_mutex;
+	size_t fat_size;
+	size_t fat_count;
+
+	mutex_t root_mutex;
+	fatnode_t *root;
+
+	mutex_t vnode_map_mutex;
+	hashtable_t vnode_map; // <dent disk offset> -> vnode
+} fatfs_t;
+
+fatnode_t *fatfs_allocate_node(vfs_t *vfs, int type);
+int fatfs_directory_lookup(fatfs_t *fatfs, fatnode_t *fatnode, const char *name, fatfs_dent_t *dent_out, size_t *disk_offset_out); // if disk_offset_out is NULL, remove the dent
+int fatfs_directory_get_dent(fatfs_t *fatfs, fatnode_t *fatnode, size_t dent_offset, char *name_out, fatfs_dent_t *dent_out, size_t *disk_offset);
+int fatfs_next_cluster(fatfs_t *fatfs, fatfs_cluster_t cluster, fatfs_cluster_t *ret);
+bool fatfs_is_cluster_eof(fatfs_t *fs, fatfs_cluster_t cluster);
+int fatfs_cluster_chain_length(fatfs_t *fatfs, fatfs_cluster_t cluster, size_t *length);
+int fatfs_allocate_cluster(fatfs_t *fatfs, fatfs_cluster_t reference, fatfs_cluster_t *new_cluster);
+int fatfs_grow_chain(fatfs_t *fatfs, fatfs_cluster_t chain, size_t grow_count);
+void fatfs_free_node(fatnode_t *node);
+int fatfs_get_cluster_from_index(fatfs_t *fs, fatnode_t *node, uintmax_t index, fatfs_cluster_t *cluster);
+int fatfs_resize_file(fatfs_t *fatfs, fatnode_t *fatnode, size_t new_size);
+int fatfs_update_dent(fatfs_t *fatfs, fatnode_t *fatnode);
+int fatfs_rw_clusters_iovec(fatfs_t *fs, fatnode_t *node, iovec_iterator_t *iovec_iterator, size_t count, uintmax_t index, bool write, bool cache);
+int fatfs_rw_cluster_iovec(fatfs_t *fs, fatnode_t *node, iovec_iterator_t *iovec_iterator, size_t count, uintmax_t offset, uintmax_t index, bool write, bool cache);
+int fatfs_rw_bytes_iovec(fatfs_t *fs, fatnode_t *node, iovec_iterator_t *iovec_iterator, size_t count, uintmax_t offset, bool write, bool cache);
+int fatfs_rw_bytes(fatfs_t *fs, fatnode_t *node, void *buffer, size_t count, uintmax_t offset, bool write, bool cache);
+int fatfs_get_file_disk_offset(fatfs_t *fatfs, fatnode_t *node, size_t byte_offset, size_t *disk_offset);
+int fatfs_write_directory_entry(fatfs_t *fatfs, fatnode_t *fatnode, fatfs_dent_t *dent, const char *name, size_t *disk_offset);
+
+#endif