1 /* 2 3 /usr/src/ext2ed/blockbitmap_com.c 4 5 A part of the extended file system 2 disk editor. 6 7 ------------------------- 8 Handles the block bitmap. 9 ------------------------- 10 11 This file implements the commands which are specific to the blockbitmap type. 12 13 First written on: July 5 1995 14 15 Copyright (C) 1995 Gadi Oxman 16 17 */ 18 19 #include "config.h" 20 #include <stdio.h> 21 #include <stdlib.h> 22 #include <string.h> 23 24 #include "ext2ed.h" 25 26 /* 27 28 The functions in this file use the flobal structure block_bitmap_info. This structure contains the current 29 position in the bitmap. 30 31 */ 32 33 void type_ext2_block_bitmap___entry (char *command_line) 34 35 /* 36 37 This function changes the current entry in the bitmap. It just changes the entry_num variable in block_bitmap_info 38 and dispatches a show command to show the new entry. 39 40 */ 41 42 { 43 unsigned long entry_num; 44 char *ptr,buffer [80]; 45 46 47 48 ptr=parse_word (command_line,buffer); /* Get the requested entry */ 49 if (*ptr==0) { 50 wprintw (command_win,"Error - No argument specified\n"); 51 refresh_command_win (); return; 52 } 53 ptr=parse_word (ptr,buffer); 54 55 entry_num=atol (buffer); 56 57 58 if (entry_num >= file_system_info.super_block.s_blocks_per_group) { /* Check if it is a valid entry number */ 59 60 wprintw (command_win,"Error - Entry number out of bounds\n"); 61 refresh_command_win ();return; 62 } 63 64 65 66 block_bitmap_info.entry_num=entry_num; /* If it is, just change entry_num and */ 67 strcpy (buffer,"show");dispatch (buffer); /* dispatch a show command */ 68 } 69 70 void type_ext2_block_bitmap___next (char *command_line) 71 72 /* 73 74 This function passes to the next entry in the bitmap. We just call the above entry command. 75 76 */ 77 78 { 79 long entry_offset=1; 80 char *ptr,buffer [80]; 81 82 ptr=parse_word (command_line,buffer); 83 if (*ptr!=0) { 84 ptr=parse_word (ptr,buffer); 85 entry_offset=atol (buffer); 86 } 87 88 sprintf (buffer,"entry %ld",block_bitmap_info.entry_num+entry_offset); 89 dispatch (buffer); 90 } 91 92 void type_ext2_block_bitmap___prev (char *command_line) 93 94 { 95 long entry_offset=1; 96 char *ptr,buffer [80]; 97 98 ptr=parse_word (command_line,buffer); 99 if (*ptr!=0) { 100 ptr=parse_word (ptr,buffer); 101 entry_offset=atol (buffer); 102 } 103 104 sprintf (buffer,"entry %ld",block_bitmap_info.entry_num-entry_offset); 105 dispatch (buffer); 106 } 107 108 void type_ext2_block_bitmap___allocate (char *command_line) 109 110 /* 111 112 This function starts allocating block from the current position. Allocating involves setting the correct bits 113 in the bitmap. This function is a vector version of allocate_block below - We just run on the blocks that 114 we need to allocate, and call allocate_block for each one. 115 116 */ 117 118 { 119 long entry_num,num=1; 120 char *ptr,buffer [80]; 121 122 ptr=parse_word (command_line,buffer); /* Get the number of blocks to allocate */ 123 if (*ptr!=0) { 124 ptr=parse_word (ptr,buffer); 125 num=atol (buffer); 126 } 127 128 entry_num=block_bitmap_info.entry_num; 129 /* Check for limits */ 130 if (num > file_system_info.super_block.s_blocks_per_group-entry_num) { 131 wprintw (command_win,"Error - There aren't that much blocks in the group\n"); 132 refresh_command_win ();return; 133 } 134 135 while (num) { /* And call allocate_block */ 136 allocate_block (entry_num); /* for each block */ 137 num--;entry_num++; 138 } 139 140 dispatch ("show"); /* Show the result */ 141 } 142 143 void type_ext2_block_bitmap___deallocate (char *command_line) 144 145 /* This is the opposite of the above function - We call deallocate_block instead of allocate_block */ 146 147 { 148 long entry_num,num=1; 149 char *ptr,buffer [80]; 150 151 ptr=parse_word (command_line,buffer); 152 if (*ptr!=0) { 153 ptr=parse_word (ptr,buffer); 154 num=atol (buffer); 155 } 156 157 entry_num=block_bitmap_info.entry_num; 158 if (num > file_system_info.super_block.s_blocks_per_group-entry_num) { 159 wprintw (command_win,"Error - There aren't that much blocks in the group\n"); 160 refresh_command_win ();return; 161 } 162 163 while (num) { 164 deallocate_block (entry_num); 165 num--;entry_num++; 166 } 167 168 dispatch ("show"); 169 } 170 171 172 void allocate_block (long entry_num) 173 174 /* In this function we convert the bit number into the right byte and inner bit positions. */ 175 176 { 177 unsigned char bit_mask=1; 178 int byte_offset,j; 179 180 byte_offset=entry_num/8; /* Find the correct byte - entry_num/8 */ 181 /* The position inside the byte is entry_num %8 */ 182 for (j=0;j<entry_num%8;j++) 183 bit_mask*=2; /* Generate the or mask - 1 at the right place */ 184 type_data.u.buffer [byte_offset] |= bit_mask; /* And apply it */ 185 } 186 187 void deallocate_block (long entry_num) 188 189 /* This is the opposite of allocate_block above. We use an and mask instead of an or mask. */ 190 191 { 192 unsigned char bit_mask=1; 193 int byte_offset,j; 194 195 byte_offset=entry_num/8; 196 for (j=0;j<entry_num%8;j++) 197 bit_mask*=2; 198 bit_mask^=0xff; 199 200 type_data.u.buffer [byte_offset] &= bit_mask; 201 } 202 203 void type_ext2_block_bitmap___show (char *command_line) 204 205 /* 206 207 We show the bitmap as a series of bits, grouped at 8-bit intervals. We display 8 such groups on each line. 208 The current position (as known from block_bitmap_info.entry_num) is highlighted. 209 210 */ 211 212 { 213 int i,j; 214 unsigned char *ptr; 215 unsigned long block_num,entry_num; 216 217 ptr=type_data.u.buffer; 218 show_pad_info.line=0;show_pad_info.max_line=-1; 219 220 wmove (show_pad,0,0); 221 for (i=0,entry_num=0;i<file_system_info.super_block.s_blocks_per_group/8;i++,ptr++) { 222 for (j=1;j<=128;j*=2) { /* j contains the and bit mask */ 223 if (entry_num==block_bitmap_info.entry_num) { /* Highlight the current entry */ 224 wattrset (show_pad,A_REVERSE); 225 show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines/2; 226 } 227 228 if ((*ptr) & j) /* Apply the mask */ 229 wprintw (show_pad,"1"); 230 else 231 wprintw (show_pad,"0"); 232 233 if (entry_num==block_bitmap_info.entry_num) 234 wattrset (show_pad,A_NORMAL); 235 236 entry_num++; /* Pass to the next entry */ 237 } 238 wprintw (show_pad," "); 239 if (i%8==7) { /* Display 8 groups in a row */ 240 wprintw (show_pad,"\n"); 241 show_pad_info.max_line++; 242 } 243 } 244 245 refresh_show_pad (); 246 show_info (); /* Show the usual information */ 247 248 /* Show the group number */ 249 wmove (show_win,1,0); 250 wprintw (show_win,"Block bitmap of block group %ld\n",block_bitmap_info.group_num); 251 /* Show the block number */ 252 253 block_num=block_bitmap_info.entry_num+block_bitmap_info.group_num*file_system_info.super_block.s_blocks_per_group; 254 block_num+=file_system_info.super_block.s_first_data_block; 255 256 wprintw (show_win,"Status of block %ld - ",block_num); /* and the allocation status */ 257 ptr=type_data.u.buffer+block_bitmap_info.entry_num/8; 258 j=1; 259 for (i=block_bitmap_info.entry_num % 8;i>0;i--) 260 j*=2; 261 if ((*ptr) & j) 262 wprintw (show_win,"Allocated\n"); 263 else 264 wprintw (show_win,"Free\n"); 265 refresh_show_win (); 266 } 267
