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238 volume VI os16 Script e sorgenti del kernel 239 « 890106 | name_unlink = basename (path_unlink); 890107 | // 890108 | // Read the directory content and try to locate the item to unlink. 890109 | // 890110 | for (start = 0; 890111 | start < inode_directory->size; 890112 | start += inode_directory->sb->blksize) 890113 | { 890114 | size_read = inode_file_read (inode_directory, start, buffer, 890115 | inode_directory->sb->blksize, 890116 | NULL); 890117 | if (size_read < sizeof (directory_t)) 890118 | { 890119 | break; 890120 | } 890121 | // 890122 | // Scan the directory portion just read, for the item to unlink. 890123 | // 890124 | dir = (directory_t *) buffer; 890125 | // 890126 | for (d = 0; d < size_read; d += (sizeof (directory_t)), dir++) 890127 | { 890128 | if (dir->ino != 0 && 890129 | strncmp (dir->name, name_unlink, NAME_MAX) == 0) 890130 | { 890131 | // 890132 | // Found the corresponding item: unlink the inode. 890133 | // 890134 | dir->ino = 0; 890135 | // 890136 | // Update the directory inside the file system. 890137 | // 890138 | size_written = inode_file_write (inode_directory, start, 890139 | buffer, size_read); 890140 | if (size_written != size_read) 890141 | { 890142 | // 890143 | // Write problem: just tell. 890144 | // 890145 | k_printf ("kernel alert: directory write error!\n"); 890146 | } 890147 | // 890148 | // Update directory inode and put inode. If the unlinked 890149 | // inode was a directory, the parent directory inode 890150 | // must reduce the file system link count. 890151 | // 890152 | if (S_ISDIR (inode_unlink->mode)) 890153 | { 890154 | inode_directory->links--; 890155 | } 890156 | inode_directory->time = k_time (NULL); 890157 | inode_directory->changed = 1; 890158 | inode_put (inode_directory); 890159 | // 890160 | // Reduce link inside unlinked inode and put inode. 890161 | // 890162 | inode_unlink->links--; 890163 | inode_unlink->changed = 1; 890164 | inode_unlink->time = k_time (NULL); 890165 | inode_put (inode_unlink); 890166 | // 890167 | // Just return, as the work is done. 890168 | // 890169 | return (0); 890170 | } 890171 | } 890172 | } 890173 | // 890174 | // At this point, it was not possible to unlink the file. 890175 | // 890176 | inode_put (inode_unlink); 890177 | inode_put (inode_directory); 890178 | errset (EUNKNOWN); // Unknown error. 890179 | return (-1); 890180 |} 104.4.47 kernel/fs/sb_inode_status.c Si veda la sezione 103.3.45. 900001 |#include 900002 |#include 900003 |//---------------------------------------------------------------------- 900004 |int 900005 |sb_inode_status (sb_t *sb, ino_t ino) 900006 |{ 900007 | int map_element; 900008 | int map_bit; 900009 | int map_mask; 900010 | // 900011 | // Check arguments. 900012 | // 900013 | if (ino == 0 || sb == NULL) 900014 | { 900015 | errset (EINVAL); // Invalid argument. 900016 | return (-1); 900017 | } 900018 | // 900019 | // Calculate the map element, the map bit and the map mask. 900020 | // 900021 | map_element = ino / 16; 900022 | map_bit = ino % 16; 900023 | map_mask = 1 map_inode[map_element] & map_mask) 900028 | { 900029 | return (1); // True. 900030 | } 900031 | else 900032 | { 900033 | return (0); // False. 900034 | } 900035 |} 104.4.48 kernel/fs/sb_mount.c Si veda la sezione 103.3.46. 910001 |#include 910002 |#include 910003 |#include 910004 |//---------------------------------------------------------------------- 910005 |sb_t * 910006 |sb_mount (dev_t device, inode_t **inode_mnt, int options) 910007 |{ 910008 | sb_t *sb; 910009 | ssize_t size_read; 910010 | addr_t start; 910011 | int m; 910012 | size_t size_sb; 910013 | size_t size_map; 910014 | // 910015 | // Find if it is already mounted. 910016 | // 910017 | sb = sb_reference (device); 910018 | if (sb != NULL) 910019 | { 910020 | errset (EBUSY); // Device or resource busy: device 910021 | return (NULL); // already mounted. 910022 | } 910023 | // 910024 | // Find if ‘*inode_mnt’ is already mounting something. 910025 | // 910026 | if (*inode_mnt != NULL && (*inode_mnt)->sb_attached != NULL) 910027 | { 910028 | errset (EBUSY); // Device or resource busy: mount point 910029 | return (NULL); // already used. 910030 | } 910031 | // 910032 | // The inode is not yet mounting anything, or it is new: find a free 910033 | // slot inside the super block table. 910034 | // 910035 | sb = sb_reference ((dev_t) -1); 910036 | if (sb == NULL) 910037 | { 910038 | errset (EBUSY); // Device or resource busy: 910039 | return (NULL); // no free slots. 910040 | } 910041 | // 910042 | // A free slot was found: the super block header must be loaded, but 910043 | // before it is necessary to calculate the header size to be read. 910044 | // 910045 | size_sb = offsetof (sb_t, device); 910046 | // 910047 | // Then fix the starting point. 910048 | // 910049 | start = 1024; // After boot block. 910050 | // 910051 | // Read the file system super block header. 910052 | // 910053 | size_read = dev_io ((pid_t) -1, device, DEV_READ, start, sb, 910054 | size_sb, NULL); 910055 | if (size_read != size_sb) 910056 | { 910057 | errset (EIO); // I/O error. 910058 | return (NULL); 910059 | } 910060 | // 910061 | // Save some more data. 910062 | // 910063 | sb->device = device; 910064 | sb->options = options; 910065 | sb->inode_mounted_on = *inode_mnt; 910066 | sb->blksize = (1024 log2_size_zone); 910067 | // 910068 | // Check if the super block data is valid. 910069 | // 910070 | if (sb->magic_number != 0x137F) 910071 | { 910072 | errset (ENODEV); // No such device: unsupported 910073 | sb->device = 0; // file system type. 910074 | return (NULL); 910075 | } 910076 | if (sb->map_inode_blocks > SB_MAX_INODE_BLOCKS) 910077 | { 910078 | errset (E_MAP_INODE_TOO_BIG); 910079 | return (NULL); 910080 | } 910081 | if (sb->map_zone_blocks > SB_MAX_ZONE_BLOCKS) 910082 | { 910083 | errset (E_MAP_ZONE_TOO_BIG); 910084 | return (NULL); 910085 | } 910086 | if (sb->blksize > SB_MAX_ZONE_SIZE) 910087 | { 910088 | errset (E_DATA_ZONE_TOO_BIG); 910089 | return (NULL); 910090 | } 910091 | // 910092 | // A right super block header was loaded from disk, now load the 910093 | // super block inode bit map. 910094 | // 910095 | start = 1024; // After boot block. 910096 | start += 1024; // After super block. 910097 | for (m = 0; m < SB_MAP_INODE_SIZE; m++) // 910098 | { // Reset map in memory, 910099 | sb->map_inode[m] = 0xFFFF; // before loading. 910100 | } // 910101 | size_map = sb->map_inode_blocks * 1024; 910102 | size_read = dev_io ((pid_t) -1, sb->device, DEV_READ, start, 910103 | sb->map_inode, size_map, NULL); 910104 | if (size_read != size_map) 910105 | { 910106 | errset (EIO); // I/O error. 910107 | return (NULL); 910108 | } 910109 | // 910110 | // Load the super block zone bit map. 910111 | // 910112 | start = 1024; // After boot block. 910113 | start += 1024; // After super block. 910114 | start += (sb->map_inode_blocks * 1024); // After inode bit map. «
240 volume VI os16 Script e sorgenti del kernel 241 « « 910115 | for (m = 0; m < SB_MAP_ZONE_SIZE; m++) // 910116 | { // Reset map in memory, 910117 | sb->map_zone[m] = 0xFFFF; // before loading. 910118 | } // 910119 | size_map = sb->map_zone_blocks * 1024; 910120 | size_read = dev_io ((pid_t) -1, sb->device, DEV_READ, start, 910121 | sb->map_zone, size_map, NULL); 910122 | if (size_read != size_map) 910123 | { 910124 | errset (EIO); // I/O error. 910125 | return (NULL); 910126 | } 910127 | // 910128 | // Check the inode that should mount the super block. If 910129 | // ‘*inode_mnt’ is ‘NULL’, then it is meant to be the first mount of 910130 | // the root file system. In such case, the inode must be loaded too, 910131 | // and the value for ‘*inode_mnt’ must be modified. 910132 | // 910133 | if (*inode_mnt == NULL) 910134 | { 910135 | *inode_mnt = inode_get (device, 1); 910136 | } 910137 | // 910138 | // Check for a valid value. 910139 | // 910140 | if (*inode_mnt == NULL) 910141 | { 910142 | // 910143 | // This is bad! 910144 | // 910145 | errset (EUNKNOWN); // Unknown error. 910146 | return (NULL); 910147 | } 910148 | // 910149 | // A valid inode is available for the mount. 910150 | // 910151 | (*inode_mnt)->sb_attached = sb; 910152 | // 910153 | // Return the super block pointer. 910154 | // 910155 | return (sb); 910156 |} 104.4.49 kernel/fs/sb_reference.c Si veda la sezione 103.3.47. 920001 |#include 920002 |#include 920003 |//---------------------------------------------------------------------- 920004 |sb_t * 920005 |sb_reference (dev_t device) 920006 |{ 920007 | int s; // Slot index. 920008 | // 920009 | // If device is zero, a reference to the whole table is returned. 920010 | // 920011 | if (device == 0) 920012 | { 920013 | return (sb_table); 920014 | } 920015 | // 920016 | // If device is ((dev_t) -1), a reference to a free slot is 920017 | // returned. 920018 | // 920019 | if (device == ((dev_t) -1)) 920020 | { 920021 | for (s = 0; s < SB_MAX_SLOTS; s++) 920022 | { 920023 | if (sb_table[s].device == 0) 920024 | { 920025 | return (&sb_table[s]); 920026 | } 920027 | } 920028 | return (NULL); 920029 | } 920030 | // 920031 | // A device was selected: find the super block associated to it. 920032 | // 920033 | for (s = 0; s < SB_MAX_SLOTS; s++) 920034 | { 920035 | if (sb_table[s].device == device) 920036 | { 920037 | return (&sb_table[s]); 920038 | } 920039 | } 920040 | // 920041 | // The super block was not found. 920042 | // 920043 | return (NULL); 920044 |} 104.4.50 kernel/fs/sb_save.c Si veda la sezione 103.3.48. 930001 |#include 930002 |#include 930003 |#include 930004 |//---------------------------------------------------------------------- 930005 |int 930006 |sb_save (sb_t *sb) 930007 |{ 930008 | ssize_t size_written; 930009 | addr_t start; 930010 | size_t size_map; 930011 | // 930012 | // Check for valid argument. 930013 | // 930014 | if (sb == NULL) 930015 | { 930016 | errset (EINVAL); // Invalid argument. 930017 | return (-1); 930018 | } 930019 | // 930020 | // Check if the super block changed for some reason (only the 930021 | // inode and the zone maps can change really). 930022 | // 930023 | if (!sb->changed) 930024 | { 930025 | // 930026 | // Nothing to save. 930027 | // 930028 | return (0); 930029 | } 930030 | // 930031 | // Something inside the super block changed: start the procedure to 930032 | // save the inode map (recall that the super block header is not 930033 | // saved, because it never changes). 930034 | // 930035 | start = 1024; // After boot block. 930036 | start += 1024; // After super block. 930037 | size_map = sb->map_inode_blocks * 1024; 930038 | size_written = dev_io ((pid_t) -1, sb->device, DEV_WRITE, start, 930039 | sb->map_inode, size_map, NULL); 930040 | if (size_written != size_map) 930041 | { 930042 | // 930043 | // Error writing the map. 930044 | // 930045 | errset (EIO); // I/O error. 930046 | return (-1); 930047 | } 930048 | // 930049 | // Start the procedure to save the zone map. 930050 | // 930051 | start = 1024; // After boot block. 930052 | start += 1024; // After super block. 930053 | start += (sb->map_inode_blocks * 1024); // After inode bit map. 930054 | size_map = sb->map_zone_blocks * 1024; 930055 | size_written = dev_io ((pid_t) -1, sb->device, DEV_WRITE, start, 930056 | sb->map_zone, size_map, NULL); 930057 | if (size_written != size_map) 930058 | { 930059 | // 930060 | // Error writing the map. 930061 | // 930062 | errset (EIO); // I/O error. 930063 | return (-1); 930064 | } 930065 | // 930066 | // Super block saved. 930067 | // 930068 | sb->changed = 0; 930069 | // 930070 | return (0); 930071 |} 104.4.51 kernel/fs/sb_table.c Si veda la sezione 103.3.47. 940001 |#include 940002 |//---------------------------------------------------------------------- 940003 |sb_t sb_table[SB_MAX_SLOTS]; 104.4.52 kernel/fs/sb_zone_status.c Si veda la sezione 103.3.45. 950001 |#include 950002 |#include 950003 |//---------------------------------------------------------------------- 950004 |int 950005 |sb_zone_status (sb_t *sb, zno_t zone) 950006 |{ 950007 | int map_element; 950008 | int map_bit; 950009 | int map_mask; 950010 | // 950011 | // Check arguments. 950012 | // 950013 | if (zone == 0 || sb == NULL) 950014 | { 950015 | errset (EINVAL); // Invalid argument. 950016 | return (-1); 950017 | } 950018 | // 950019 | // Calculate the map element, the map bit and the map mask. 950020 | // 950021 | map_element = zone / 16; 950022 | map_bit = zone % 16; 950023 | map_mask = 1 map_zone[map_element] & map_mask) 950028 | { 950029 | return (1); // True. 950030 | } 950031 | else 950032 | { 950033 | return (0); // False. 950034 | } 950035 |} 104.4.53 kernel/fs/zone_alloc.c Si veda la sezione 103.3.51. 960001 |#include 960002 |#include 960003 |#include 960004 |//---------------------------------------------------------------------- 960005 |zno_t 960006 |zone_alloc (sb_t *sb) 960007 |{ « « «
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