| 0,0 → 1,95 |
|---|
| /* This file contains the procedures for support directory operations. */ |
| |
| /* Methods: |
| * do_sum: return total number of directory entries |
| * do_readentry: fill in the user buffer with directory entry specified by number |
| */ |
| |
| |
| #include <stdio.h> |
| #include "fs.h" |
| #include "dir.h" |
| #include "block.h" |
| #include "inode.h" |
| #include "param.h" |
| |
| |
| int do_sum() |
| { |
| |
| /* Perform dsum system call. */ |
| |
| inode_t *rip; |
| int dir_count; |
| offset_t dir_size; |
| |
| rip = fp->fp_workdir; |
| dir_size = rip->i_size; |
| |
| /* We must calculate with both versions of directory entry sizes. */ |
| if (rip->i_sp->s_extend) { |
| dir_count = dir_size/DIR_ENTRY_SIZE; |
| } |
| else { |
| dir_count = dir_size/DIR_ENTRY_SIZE_EX; |
| } |
| if (dir_size % DIR_ENTRY_SIZE_EX != 0) { |
| print_console("dir_size % DIR_ENTRY_SIZE_EX != 0\n"); |
| } |
| |
| return dir_count; |
| } |
| |
| |
| int do_readentry() |
| { |
| |
| /* Perform readentry(numb, buffer) system call. */ |
| |
| int actual_sum, extend; |
| offset_t pos; |
| inode_t *rip; |
| block_num_t b; |
| block_t *bp; |
| register int r; |
| direct_t *dir; |
| directex_t *direx; |
| |
| /* Get actual number of directory entries within the block. */ |
| actual_sum = do_sum(); |
| if (entry_number < 0 || actual_sum <= entry_number) |
| return FS_EINVAL; |
| |
| rip = fp->fp_workdir; |
| extend = rip->i_sp->s_extend; |
| |
| if (extend) { |
| pos = entry_number * DIR_ENTRY_SIZE_EX; |
| } |
| else { |
| pos = entry_number * DIR_ENTRY_SIZE; |
| } |
| |
| /* Get number of block within the entry is. */ |
| b = read_map(rip, pos); |
| if (b == NO_BLOCK) |
| return 0; |
| |
| bp = get_block(b); |
| |
| /* Copy the entry data into address space of actual consument. */ |
| if (extend) { |
| direx = &bp->b.b__direx[entry_number]; |
| memcpy(fp->buffer, (void*)direx, DIR_ENTRY_SIZE_EX); |
| } |
| else { |
| dir = &bp->b.b__dir[entry_number]; |
| memcpy(fp->buffer, (void*)dir, DIR_ENTRY_SIZE); |
| } |
| |
| r = (extend ? DIR_ENTRY_SIZE_EX : DIR_ENTRY_SIZE); |
| |
| return r; |
| } |
| |
| |