minix3/fs/iso9660fs/inode.c

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2020-02-21 00:59:27 +05:30
/* This file contains all the function that handle the dir records
* (inodes) for the ISO9660 filesystem.*/
#include "inc.h"
#include "buf.h"
#include <minix/vfsif.h>
/*===========================================================================*
* fs_putnode *
*===========================================================================*/
int fs_putnode()
{
/* Find the inode specified by the request message and decrease its counter. */
int count;
struct dir_record *dir = NULL;
dir = get_dir_record(fs_m_in.m_vfs_fs_putnode.inode);
release_dir_record(dir);
count = fs_m_in.m_vfs_fs_putnode.count;
if (count <= 0) return(EINVAL);
if (count > dir->d_count) {
printf("put_inode: count too high: %d > %d\n", count, dir->d_count);
return(EINVAL);
}
if (dir->d_count > 1)
dir->d_count = dir->d_count - count + 1;/*Keep at least one reference*/
release_dir_record(dir); /* Actual inode release, might be last reference */
return(OK);
}
/*===========================================================================*
* release_dir_record *
*===========================================================================*/
int release_dir_record(dir)
struct dir_record *dir;
{
/* Release a dir record (decrement the counter) */
if (dir == NULL)
return(EINVAL);
if (--dir->d_count == 0) {
if (dir->ext_attr != NULL)
dir->ext_attr->count = 0;
dir->ext_attr = NULL;
dir->d_mountpoint = FALSE;
dir->d_prior = NULL;
if (dir->d_next != NULL)
release_dir_record(dir);
dir->d_next = NULL;
}
return(OK);
}
/*===========================================================================*
* get_free_dir_record *
*===========================================================================*/
struct dir_record *get_free_dir_record(void)
{
/* Get a free dir record */
struct dir_record *dir;
for(dir = dir_records; dir < &dir_records[NR_ATTR_RECS]; dir++) {
if (dir->d_count == 0) { /* The record is free */
dir->d_count = 1; /* Set count to 1 */
dir->ext_attr = NULL;
return(dir);
}
}
return(NULL);
}
/*===========================================================================*
* get_dir_record *
*===========================================================================*/
struct dir_record *get_dir_record(id_dir_record)
ino_t id_dir_record;
{
struct dir_record *dir = NULL;
u32_t address;
int i;
/* Search through the cache if the inode is still present */
for(i = 0; i < NR_DIR_RECORDS && dir == NULL; ++i) {
if (dir_records[i].d_ino_nr == id_dir_record
&& dir_records[i].d_count > 0) {
dir = dir_records + i;
dir->d_count++;
}
}
if (dir == NULL) {
address = (u32_t)id_dir_record;
dir = load_dir_record_from_disk(address);
}
if (dir == NULL) return(NULL);
return(dir);
}
/*===========================================================================*
* get_free_ext_attr *
*===========================================================================*/
struct ext_attr_rec *get_free_ext_attr(void) {
/* Get a free extended attribute structure */
struct ext_attr_rec *dir;
for(dir = ext_attr_recs; dir < &ext_attr_recs[NR_ATTR_RECS]; dir++) {
if (dir->count == 0) { /* The record is free */
dir->count = 1;
return(dir);
}
}
return(NULL);
}
/*===========================================================================*
* create_ext_attr *
*===========================================================================*/
int create_ext_attr(struct ext_attr_rec *ext,char *buffer)
{
/* Fill an extent structure from the data read on the device */
if (ext == NULL) return(EINVAL);
/* In input we have a stream of bytes that are physically read from the
* device. This stream of data is copied to the data structure. */
memcpy(&ext->own_id,buffer,sizeof(u32_t));
memcpy(&ext->group_id,buffer + 4,sizeof(u32_t));
memcpy(&ext->permissions,buffer + 8,sizeof(u16_t));
memcpy(&ext->file_cre_date,buffer + 10,ISO9660_SIZE_VOL_CRE_DATE);
memcpy(&ext->file_mod_date,buffer + 27,ISO9660_SIZE_VOL_MOD_DATE);
memcpy(&ext->file_exp_date,buffer + 44,ISO9660_SIZE_VOL_EXP_DATE);
memcpy(&ext->file_eff_date,buffer + 61,ISO9660_SIZE_VOL_EFF_DATE);
memcpy(&ext->rec_format,buffer + 78,sizeof(u8_t));
memcpy(&ext->rec_attrs,buffer + 79,sizeof(u8_t));
memcpy(&ext->rec_length,buffer + 80,sizeof(u32_t));
memcpy(&ext->system_id,buffer + 84,ISO9660_SIZE_SYS_ID);
memcpy(&ext->system_use,buffer + 116,ISO9660_SIZE_SYSTEM_USE);
memcpy(&ext->ext_attr_rec_ver,buffer + 180,sizeof(u8_t));
memcpy(&ext->len_esc_seq,buffer + 181,sizeof(u8_t));
return(OK);
}
/*===========================================================================*
* create_ext_attr *
*===========================================================================*/
int create_dir_record(dir,buffer,address)
struct dir_record *dir;
char *buffer;
u32_t address;
{
/* Fills a dir record structure from the data read on the device */
/* If the flag assign id is active it will return the id associated;
* otherwise it will return OK. */
short size;
size = buffer[0];
if (dir == NULL) return(EINVAL);
/* The data structure dir record is filled with the stream of data
* that is read. */
dir->length = size;
dir->ext_attr_rec_length = *((u8_t*)buffer + 1);
memcpy(&dir->loc_extent_l,buffer + 2,sizeof(u32_t));
memcpy(&dir->loc_extent_m,buffer + 6,sizeof(u32_t));
memcpy(&dir->data_length_l,buffer + 10,sizeof(u32_t));
memcpy(&dir->data_length_m,buffer + 14,sizeof(u32_t));
memcpy(dir->rec_date,buffer + 18, sizeof(dir->rec_date));
dir->file_flags = *((u8_t*)buffer + 25);
dir->file_unit_size = *((u8_t*)buffer + 26);
dir->inter_gap_size = *((u8_t*)buffer + 27);
dir->vol_seq_number = *((u8_t*)buffer + 28);
dir->length_file_id = *((u8_t*)buffer + 32);
memcpy(dir->file_id,buffer + 33,dir->length_file_id);
dir->ext_attr = NULL;
/* set memory attrs */
if ((dir->file_flags & D_TYPE) == D_DIRECTORY)
dir->d_mode = I_DIRECTORY;
else
dir->d_mode = I_REGULAR;
/* Set permission to read only. Equal for all users. */
dir->d_mode |= R_BIT | X_BIT;
dir->d_mode |= R_BIT << 3 | X_BIT << 3;
dir->d_mode |= R_BIT << 6 | X_BIT << 6;
dir->d_mountpoint = FALSE;
dir->d_next = NULL;
dir->d_prior = NULL;
dir->d_file_size = dir->data_length_l;
/* Set physical address of the dir record */
dir->d_phy_addr = address;
dir->d_ino_nr = address;
return(OK);
}
/*===========================================================================*
* load_dir_record_from_disk *
*===========================================================================*/
struct dir_record *load_dir_record_from_disk(address)
u32_t address;
{
/* This function load a particular dir record from a specific address
* on the device */
int block_nr, offset, block_size, new_pos;
struct buf *bp;
struct dir_record *dir, *dir_next, *dir_parent, *dir_tmp;
char name[NAME_MAX + 1];
char old_name[NAME_MAX + 1];
u32_t new_address, size;
block_size = v_pri.logical_block_size_l; /* Block size */
block_nr = address / block_size; /* Block number from the address */
offset = address % block_size; /* Offset starting from the block */
bp = get_block(block_nr); /* Read the block from the device */
if (bp == NULL)
return(NULL);
dir = get_free_dir_record(); /* Get a free record */
if (dir == NULL)
return(NULL);
/* Fill the dir record with the data read from the device */
create_dir_record(dir,b_data(bp) + offset, address);
/* In case the file is composed of more file sections, load also the
* next section into the structure */
new_pos = offset + dir->length;
dir_parent = dir;
new_address = address + dir->length;
while (new_pos < block_size) {
dir_next = get_free_dir_record();
create_dir_record(dir_next, b_data(bp) + new_pos, new_address);
if (dir_next->length > 0) {
strncpy(name,dir_next->file_id,dir_next->length_file_id);
name[dir_next->length_file_id] = '\0';
strncpy(old_name, dir_parent->file_id,
dir_parent->length_file_id);
old_name[dir_parent->length_file_id] = '\0';
if (strcmp(name, old_name) == 0) {
dir_parent->d_next = dir_next;
dir_next->d_prior = dir_parent;
/* Link the dir records */
dir_tmp = dir_next;
size = dir_tmp->data_length_l;
/* Update the file size */
while (dir_tmp->d_prior != NULL) {
dir_tmp = dir_tmp->d_prior;
size += dir_tmp->data_length_l;
dir_tmp->d_file_size = size;
}
new_pos += dir_parent->length;
new_address += dir_next->length;
dir_parent = dir_next;
} else { /* This is another inode. */
release_dir_record(dir_next);
new_pos = block_size;
}
} else { /* record not valid */
release_dir_record(dir_next);
new_pos = block_size; /* Exit from the while */
}
}
put_block(bp); /* Release the block read. */
return(dir);
}