minix/fs/iso9660fs/path.c

   1 #include "inc.h"
   2 #include <string.h>
   3 #include <minix/com.h>
   4 #include <minix/vfsif.h>
   5
   6 #include "buf.h"
   7
   8 static char *get_name(char *name, char string[NAME_MAX+1]);
   9 static int parse_path(ino_t dir_ino, ino_t root_ino, int flags, struct
  10         dir_record **res_inop, size_t *offsetp);
  11
  12
  13 /*===========================================================================*
  14  *                             fs_lookup                                     *
  15  *===========================================================================*/
  16 int fs_lookup() {
  17   cp_grant_id_t grant;
  18   int r, len, flags;
  19   size_t offset;
  20   ino_t dir_ino, root_ino;
  21   struct dir_record *dir;
  22
  23   grant         = fs_m_in.m_vfs_fs_lookup.grant_path;
  24   len           = fs_m_in.m_vfs_fs_lookup.path_len;     /* including terminating nul */
  25   dir_ino       = fs_m_in.m_vfs_fs_lookup.dir_ino;
  26   root_ino      = fs_m_in.m_vfs_fs_lookup.root_ino;
  27   flags         = fs_m_in.m_vfs_fs_lookup.flags;
  28   caller_uid    = fs_m_in.m_vfs_fs_lookup.uid;
  29   caller_gid    = fs_m_in.m_vfs_fs_lookup.gid;
  30
  31   /* Check length. */
  32   if(len > sizeof(user_path)) return(E2BIG);    /* too big for buffer */
  33   if(len < 1) return(EINVAL);                   /* too small */
  34
  35   /* Copy the pathname and set up caller's user and group id */
  36   r = sys_safecopyfrom(VFS_PROC_NR, grant, 0, (vir_bytes) user_path,
  37                        (phys_bytes) len);
  38   if (r != OK) {
  39         printf("ISOFS %s:%d sys_safecopyfrom failed: %d\n",
  40                 __FILE__, __LINE__, r);
  41         return(r);
  42   }
  43
  44   /* Verify this is a null-terminated path. */
  45   if(user_path[len-1] != '\0') return(EINVAL);
  46
  47   /* Lookup inode */
  48   dir = NULL;
  49   offset = 0;
  50   r = parse_path(dir_ino, root_ino, flags, &dir, &offset);
  51
  52   if (r == ELEAVEMOUNT) {
  53         /* Report offset and the error */
  54         fs_m_out.m_fs_vfs_lookup.offset = offset;
  55         fs_m_out.m_fs_vfs_lookup.symloop = 0;
  56         return(r);
  57   }
  58
  59   if (r != OK && r != EENTERMOUNT) return(r);
  60
  61   fs_m_out.m_fs_vfs_lookup.inode        = ID_DIR_RECORD(dir);
  62   fs_m_out.m_fs_vfs_lookup.mode         = dir->d_mode;
  63   fs_m_out.m_fs_vfs_lookup.file_size    = dir->d_file_size;
  64   fs_m_out.m_fs_vfs_lookup.symloop      = 0;
  65   fs_m_out.m_fs_vfs_lookup.uid          = SYS_UID;      /* root */
  66   fs_m_out.m_fs_vfs_lookup.gid          = SYS_GID;      /* operator */
  67
  68   if (r == EENTERMOUNT) {
  69         fs_m_out.m_fs_vfs_lookup.offset = offset;
  70         release_dir_record(dir);
  71   }
  72
  73   return(r);
  74 }
  75
  76 /* The search dir actually performs the operation of searching for the
  77  * compoent ``string" in ldir_ptr. It returns the response and the number of
  78  * the inode in numb. */
  79 /*===========================================================================*
  80  *                              search_dir                                   *
  81  *===========================================================================*/
  82 int search_dir(
  83         register struct dir_record *ldir_ptr,   /* dir record parent */
  84         char string[NAME_MAX],                  /* component to search for */
  85         ino_t *numb                             /* pointer to new dir record */
  86 ) {
  87   struct dir_record *dir_tmp;
  88   register struct buf *bp;
  89   int pos;
  90   char* comma_pos = NULL;
  91   char tmp_string[NAME_MAX];
  92
  93   /* This function search a particular element (in string) in a inode and
  94    * return its number */
  95
  96   /* Initialize the tmp array */
  97   memset(tmp_string,'\0',NAME_MAX);
  98
  99   if ((ldir_ptr->d_mode & I_TYPE) != I_DIRECTORY) {
 100     return(ENOTDIR);
 101   }
 102
 103   if (strcmp(string,".") == 0) {
 104     *numb = ID_DIR_RECORD(ldir_ptr);
 105     return OK;
 106   }
 107
 108   if (strcmp(string,"..") == 0 && ldir_ptr->loc_extent_l == v_pri.dir_rec_root->loc_extent_l) {
 109     *numb = ROOT_INO_NR;
 110 /*     *numb = ID_DIR_RECORD(ldir_ptr); */
 111     return OK;
 112   }
 113
 114   /* Read the dir's content */
 115   pos = ldir_ptr->ext_attr_rec_length;
 116   bp = get_block(ldir_ptr->loc_extent_l);
 117
 118   if (bp == NULL)
 119     return EINVAL;
 120
 121   while (pos < v_pri.logical_block_size_l) {
 122     if ((dir_tmp = get_free_dir_record()) == NULL) {
 123       put_block(bp);
 124       return EINVAL;
 125     }
 126
 127     if (create_dir_record(dir_tmp,b_data(bp) + pos,
 128           ldir_ptr->loc_extent_l*v_pri.logical_block_size_l + pos) == EINVAL)
 129       return EINVAL;
 130
 131     if (dir_tmp->length == 0) {
 132       release_dir_record(dir_tmp);
 133       put_block(bp);
 134       return EINVAL;
 135     }
 136
 137     memcpy(tmp_string,dir_tmp->file_id,dir_tmp->length_file_id);
 138     comma_pos = strchr(tmp_string,';');
 139     if (comma_pos != NULL)
 140       *comma_pos = 0;
 141     else
 142       tmp_string[dir_tmp->length_file_id] = 0;
 143     if (tmp_string[strlen(tmp_string) - 1] == '.')
 144       tmp_string[strlen(tmp_string) - 1] = '\0';
 145
 146     if (strcmp(tmp_string,string) == 0 ||
 147         (dir_tmp->file_id[0] == 1 && strcmp(string,"..") == 0)) {
 148
 149       /* If the element is found or we are searchig for... */
 150
 151       if (dir_tmp->loc_extent_l == dir_records->loc_extent_l) {
 152         /* In this case the inode is a root because the parent
 153          * points to the same location than the inode. */
 154         *numb = 1;
 155         release_dir_record(dir_tmp);
 156         put_block(bp);
 157         return OK;
 158       }
 159
 160       if (dir_tmp->ext_attr_rec_length != 0) {
 161         dir_tmp->ext_attr = get_free_ext_attr();
 162         create_ext_attr(dir_tmp->ext_attr,b_data(bp));
 163       }
 164
 165       *numb = ID_DIR_RECORD(dir_tmp);
 166       release_dir_record(dir_tmp);
 167       put_block(bp);
 168
 169       return OK;
 170     }
 171
 172     pos += dir_tmp->length;
 173     release_dir_record(dir_tmp);
 174   }
 175
 176   put_block(bp);
 177   return EINVAL;
 178 }
 179
 180
 181 /*===========================================================================*
 182  *                             parse_path                                    *
 183  *===========================================================================*/
 184 static int parse_path(
 185 ino_t dir_ino,
 186 ino_t root_ino,
 187 int flags,
 188 struct dir_record **res_inop,
 189 size_t *offsetp
 190 ) {
 191   int r;
 192   char string[NAME_MAX+1];
 193   char *cp, *ncp;
 194   struct dir_record *start_dir, *old_dir;
 195
 196   /* Find starting inode inode according to the request message */
 197   if ((start_dir = get_dir_record(dir_ino)) == NULL) {
 198     printf("ISOFS: couldn't find starting inode %llu\n", dir_ino);
 199     return(ENOENT);
 200   }
 201
 202   cp = user_path;
 203
 204   /* Scan the path component by component. */
 205   while (TRUE) {
 206     if (cp[0] == '\0') {
 207       /* Empty path */
 208       *res_inop= start_dir;
 209       *offsetp += cp-user_path;
 210
 211       /* Return EENTERMOUNT if we are at a mount point */
 212       if (start_dir->d_mountpoint)
 213         return EENTERMOUNT;
 214
 215       return OK;
 216     }
 217
 218     if (cp[0] == '/') {
 219       /* Special case code. If the remaining path consists of just
 220        * slashes, we need to look up '.'
 221        */
 222       while(cp[0] == '/')
 223         cp++;
 224       if (cp[0] == '\0') {
 225         strlcpy(string, ".", NAME_MAX + 1);
 226         ncp = cp;
 227       }
 228       else
 229         ncp = get_name(cp, string);
 230     } else
 231       /* Just get the first component */
 232       ncp = get_name(cp, string);
 233
 234     /* Special code for '..'. A process is not allowed to leave a chrooted
 235      * environment. A lookup of '..' at the root of a mounted filesystem
 236      * has to return ELEAVEMOUNT.
 237      */
 238     if (strcmp(string, "..") == 0) {
 239
 240       /* This condition is not necessary since it will never be the root filesystem */
 241       /*       if (start_dir == dir_records) { */
 242       /*        cp = ncp; */
 243       /*        continue;       /\* Just ignore the '..' at a process' */
 244       /*                         * root. */
 245       /*                         *\/ */
 246       /*       } */
 247
 248       if (start_dir == dir_records) {
 249         /* Climbing up mountpoint */
 250         release_dir_record(start_dir);
 251         *res_inop = NULL;
 252         *offsetp += cp-user_path;
 253         return ELEAVEMOUNT;
 254       }
 255     } else {
 256       /* Only check for a mount point if we are not looking for '..'. */
 257       if (start_dir->d_mountpoint) {
 258         *res_inop= start_dir;
 259         *offsetp += cp-user_path;
 260         return EENTERMOUNT;
 261       }
 262     }
 263
 264     /* There is more path.  Keep parsing. */
 265     old_dir = start_dir;
 266
 267     r = advance(old_dir, string, &start_dir);
 268
 269     if (r != OK) {
 270       release_dir_record(old_dir);
 271       return r;
 272     }
 273
 274     release_dir_record(old_dir);
 275     cp = ncp;
 276   }
 277 }
 278
 279
 280 /*===========================================================================*
 281  *                              advance                                      *
 282  *===========================================================================*/
 283 int advance(dirp, string, resp)
 284 struct dir_record *dirp;                /* inode for directory to be searched */
 285 char string[NAME_MAX];                  /* component name to look for */
 286 struct dir_record **resp;               /* resulting inode */
 287 {
 288 /* Given a directory and a component of a path, look up the component in
 289  * the directory, find the inode, open it, and return a pointer to its inode
 290  * slot.
 291  */
 292
 293   register struct dir_record *rip = NULL;
 294   int r;
 295   ino_t numb;
 296
 297   /* If 'string' is empty, yield same inode straight away. */
 298   if (string[0] == '\0') {
 299     return ENOENT;
 300   }
 301
 302   /* Check for NULL. */
 303   if (dirp == NULL) {
 304     return EINVAL;
 305   }
 306
 307   /* If 'string' is not present in the directory, signal error. */
 308   if ( (r = search_dir(dirp, string, &numb)) != OK) {
 309     return r;
 310   }
 311
 312   /* The component has been found in the directory.  Get inode. */
 313   if ( (rip = get_dir_record((int) numb)) == NULL)  {
 314     return(err_code);
 315   }
 316
 317   *resp= rip;
 318   return OK;
 319 }
 320
 321
 322 /*===========================================================================*
 323  *                              get_name                                     *
 324  *===========================================================================*/
 325 static char *get_name(path_name, string)
 326 char *path_name;                /* path name to parse */
 327 char string[NAME_MAX+1];        /* component extracted from 'old_name' */
 328 {
 329 /* Given a pointer to a path name in fs space, 'path_name', copy the first
 330  * component to 'string' (truncated if necessary, always nul terminated).
 331  * A pointer to the string after the first component of the name as yet
 332  * unparsed is returned.  Roughly speaking,
 333  * 'get_name' = 'path_name' - 'string'.
 334  *
 335  * This routine follows the standard convention that /usr/ast, /usr//ast,
 336  * //usr///ast and /usr/ast/ are all equivalent.
 337  */
 338   size_t len;
 339   char *cp, *ep;
 340
 341   cp= path_name;
 342
 343   /* Skip leading slashes */
 344   while (cp[0] == '/')
 345         cp++;
 346
 347   /* Find the end of the first component */
 348   ep= cp;
 349   while(ep[0] != '\0' && ep[0] != '/')
 350         ep++;
 351
 352   len= ep-cp;
 353
 354   /* Truncate the amount to be copied if it exceeds NAME_MAX */
 355   if (len > NAME_MAX)
 356         len= NAME_MAX;
 357
 358   /* Special case of the string at cp is empty */
 359   if (len == 0)
 360   {
 361         /* Return "." */
 362         strlcpy(string, ".", NAME_MAX + 1);
 363   }
 364   else
 365   {
 366         memcpy(string, cp, len);
 367         string[len]= '\0';
 368   }
 369
 370   return ep;
 371 }