core/include/fs.h

   1 #ifndef FS_H
   2 #define FS_H
   3
   4 #include <linux/list.h>
   5 #include <stddef.h>
   6 #include <stdbool.h>
   7 #include <string.h>
   8 #include <com32.h>
   9 #include <stdio.h>
  10 #include <sys/dirent.h>
  11 #include <dprintf.h>
  12 #include "core.h"
  13 #include "disk.h"
  14
  15 /*
  16  * Maximum number of open files.
  17  */
  18 #define MAX_OPEN_LG2    7
  19 #define MAX_OPEN        (1 << MAX_OPEN_LG2)
  20
  21 #define FILENAME_MAX_LG2 8
  22 #define FILENAME_MAX     (1 << FILENAME_MAX_LG2)
  23
  24 #define CURRENTDIR_MAX  FILENAME_MAX
  25
  26 #define BLOCK_SIZE(fs)   ((fs)->block_size)
  27 #define BLOCK_SHIFT(fs)  ((fs)->block_shift)
  28 #define SECTOR_SIZE(fs)  ((fs)->sector_size)
  29 #define SECTOR_SHIFT(fs) ((fs)->sector_shift)
  30
  31 struct fs_info {
  32     const struct fs_ops *fs_ops;
  33     struct device *fs_dev;
  34     void *fs_info;             /* The fs-specific information */
  35     int sector_shift, sector_size;
  36     int block_shift, block_size;
  37     struct inode *root, *cwd;           /* Root and current directories */
  38     char cwd_name[CURRENTDIR_MAX];      /* Current directory by name */
  39 };
  40
  41 extern struct fs_info *this_fs;
  42
  43 struct dirent;                  /* Directory entry structure */
  44 struct file;
  45 enum fs_flags {
  46     FS_NODEV   = 1 << 0,
  47     FS_USEMEM  = 1 << 1,        /* If we need a malloc routine, set it */
  48     FS_THISIND = 1 << 2,        /* Set cwd based on config file location */
  49 };
  50
  51 struct fs_ops {
  52     /* in fact, we use fs_ops structure to find the right fs */
  53     const char *fs_name;
  54     enum fs_flags fs_flags;
  55
  56     int      (*fs_init)(struct fs_info *);
  57     void     (*searchdir)(const char *, int, struct file *);
  58     uint32_t (*getfssec)(struct file *, char *, int, bool *);
  59     void     (*close_file)(struct file *);
  60     void     (*mangle_name)(char *, const char *);
  61     size_t   (*realpath)(struct fs_info *, char *, const char *, size_t);
  62     int      (*chdir)(struct fs_info *, const char *);
  63     int      (*chdir_start)(void);
  64     int      (*open_config)(struct com32_filedata *);
  65
  66     struct inode * (*iget_root)(struct fs_info *);
  67     struct inode * (*iget)(const char *, struct inode *);
  68     int      (*readlink)(struct inode *, char *);
  69
  70     /* the _dir_ stuff */
  71     int      (*readdir)(struct file *, struct dirent *);
  72
  73     int      (*next_extent)(struct inode *, uint32_t);
  74
  75     int      (*copy_super)(void *buf);
  76 };
  77
  78 /*
  79  * Extent structure: contains the mapping of some chunk of a file
  80  * that is contiguous on disk.
  81  */
  82 struct extent {
  83     sector_t    pstart;         /* Physical start sector */
  84     uint32_t    lstart;         /* Logical start sector */
  85     uint32_t    len;            /* Number of contiguous sectors */
  86 };
  87
  88 /* Special sector numbers used for struct extent.pstart */
  89 #define EXTENT_ZERO     ((sector_t)-1) /* All-zero extent */
  90 #define EXTENT_VOID     ((sector_t)-2) /* Invalid information */
  91
  92 #define EXTENT_SPECIAL(x)       ((x) >= EXTENT_VOID)
  93
  94 /*
  95  * The inode structure, including the detail file information
  96  */
  97 struct inode {
  98     struct fs_info *fs;  /* The filesystem this inode is associated with */
  99     struct inode *parent;       /* Parent directory, if any */
 100     const char *name;           /* Name, valid for generic path search only */
 101     int          refcnt;
 102     int          mode;   /* FILE , DIR or SYMLINK */
 103     uint64_t     size;
 104     uint64_t     blocks; /* How many blocks the file take */
 105     uint64_t     ino;    /* Inode number */
 106     uint32_t     atime;  /* Access time */
 107     uint32_t     mtime;  /* Modify time */
 108     uint32_t     ctime;  /* Create time */
 109     uint32_t     dtime;  /* Delete time */
 110     uint32_t     flags;
 111     uint32_t     file_acl;
 112     struct extent this_extent, next_extent;
 113     char         pvt[0]; /* Private filesystem data */
 114 };
 115
 116 struct file {
 117     struct fs_info *fs;
 118     uint32_t offset;            /* for next read */
 119     struct inode *inode;        /* The file-specific information */
 120 };
 121
 122 /*
 123  * Struct device contains:
 124  *     the pointer points to the disk structure,
 125  *     the cache stuff.
 126  */
 127 struct cache;
 128
 129 struct device {
 130     struct disk *disk;
 131
 132     /* the cache stuff */
 133     char *cache_data;
 134     struct cache *cache_head;
 135     uint16_t cache_block_size;
 136     uint16_t cache_entries;
 137     uint32_t cache_size;
 138 };
 139
 140 /*
 141  * Our definition of "not whitespace"
 142  */
 143 static inline bool not_whitespace(char c)
 144 {
 145   return (unsigned char)c > ' ';
 146 }
 147
 148 /*
 149  * Inode allocator/deallocator
 150  */
 151 struct inode *alloc_inode(struct fs_info *fs, uint32_t ino, size_t data);
 152 static inline void free_inode(struct inode * inode)
 153 {
 154     free(inode);
 155 }
 156
 157 static inline struct inode *get_inode(struct inode *inode)
 158 {
 159     inode->refcnt++;
 160     dprintf("get_inode %p name %s refcnt %d\n",
 161             inode, inode->name, inode->refcnt);
 162     return inode;
 163 }
 164
 165 void put_inode(struct inode *inode);
 166
 167 static inline void malloc_error(char *obj)
 168 {
 169         printf("Out of memory: can't allocate memory for %s\n", obj);
 170         kaboom();
 171 }
 172
 173 /*
 174  * File handle conversion functions
 175  */
 176 extern struct file files[];
 177 static inline uint16_t file_to_handle(struct file *file)
 178 {
 179     return file ? (file - files)+1 : 0;
 180 }
 181 static inline struct file *handle_to_file(uint16_t handle)
 182 {
 183     return handle ? &files[handle-1] : NULL;
 184 }
 185
 186 struct path_entry {
 187     struct list_head list;
 188     const char *str;
 189 };
 190
 191 extern struct list_head PATH;
 192
 193 extern struct path_entry *path_add(const char *str);
 194
 195 /* fs.c */
 196 void pm_mangle_name(com32sys_t *);
 197 void pm_searchdir(com32sys_t *);
 198 void mangle_name(char *, const char *);
 199 int searchdir(const char *name, int flags);
 200 void _close_file(struct file *);
 201 size_t pmapi_read_file(uint16_t *handle, void *buf, size_t sectors);
 202 int open_file(const char *name, int flags, struct com32_filedata *filedata);
 203 void pm_open_file(com32sys_t *);
 204 void close_file(uint16_t handle);
 205 void pm_close_file(com32sys_t *);
 206 int open_config(void);
 207
 208 /* chdir.c */
 209 void pm_realpath(com32sys_t *regs);
 210 size_t realpath(char *dst, const char *src, size_t bufsize);
 211 int chdir(const char *src);
 212
 213 /* readdir.c */
 214 DIR *opendir(const char *pathname);
 215 struct dirent *readdir(DIR *dir);
 216 int closedir(DIR *dir);
 217
 218 /* getcwd.c */
 219 char *core_getcwd(char *buf, size_t size);
 220
 221 /*
 222  * Generic functions that filesystem drivers may choose to use
 223  */
 224
 225 /* chdir.c */
 226 int generic_chdir_start(void);
 227
 228 /* mangle.c */
 229 void generic_mangle_name(char *, const char *);
 230
 231 /* loadconfig.c */
 232 int search_dirs(struct com32_filedata *filedata,
 233                 const char *search_directores[], const char *filenames[],
 234                 char *realname);
 235 int generic_open_config(struct com32_filedata *filedata);
 236
 237 /* close.c */
 238 void generic_close_file(struct file *file);
 239
 240 /* getfssec.c */
 241 uint32_t generic_getfssec(struct file *file, char *buf,
 242                           int sectors, bool *have_more);
 243
 244 /* nonextextent.c */
 245 int no_next_extent(struct inode *, uint32_t);
 246
 247 #endif /* FS_H */