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/*
* Implementation of iso_file_src for:
*
* a) read from local filesystem files
* b) read from previous session / image files
*/
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <limits.h>
#include "file_src.h"
#include "messages.h"
#include "libisofs.h"
#include "util.h"
#define BLOCK_SIZE 2048
void iso_file_src_free(struct iso_file_src *src)
{
src->free_data(src);
free(src);
}
/*
* ==========================================================================
* A) FILE SRC FOR LOCAL FILESYSTEM FILES
* ==========================================================================
*/
struct local_file_data {
int fd; /* the file descriptor, once the file is opened */
off_t size; /* file size */
off_t bytes_read; /* bytes already read from file */
int error;
char *path; /* path of the file on local filesystem */
};
static
int lf_open(struct iso_file_src *src)
{
struct local_file_data *data;
assert(src);
data = (struct local_file_data*) src->data;
assert(data->fd == -1);
data->fd = open(data->path, O_RDONLY);
data->bytes_read = (off_t) 0;
data->error = 0;
return (data->fd != -1 ? 1 : 0);
}
static
void lf_close(struct iso_file_src *src)
{
struct local_file_data *data;
assert(src);
data = (struct local_file_data*) src->data;
assert(data->fd != -1);
close(data->fd);
data->fd = -1;
}
static
int lf_read_block(struct iso_file_src *src, unsigned char *buffer)
{
ssize_t bytes;
struct local_file_data *data;
assert(src);
assert(buffer);
data = (struct local_file_data*) src->data;
assert(data->fd != -1);
if (data->bytes_read >= data->size) {
return 0;
}
if (data->error) {
memset(buffer, 0, BLOCK_SIZE);
data->bytes_read += BLOCK_SIZE;
return -2;
}
bytes = 0;
do {
ssize_t result;
result = read(data->fd, buffer + bytes, BLOCK_SIZE - bytes);
if (result < 0) {
char msg[PATH_MAX + 32];
sprintf(msg, "Problem reading from %s", data->path);
iso_msg_sorry(LIBISO_CANT_READ_FILE, msg);
/* fill buffer with 0s and return */
memset(buffer + bytes, 0, BLOCK_SIZE - bytes);
data->bytes_read += BLOCK_SIZE;
return -1;
}
if (!result)
break;
bytes += result;
} while (bytes < BLOCK_SIZE);
if (bytes < BLOCK_SIZE) {
/* eof */
memset(buffer + bytes, 0, BLOCK_SIZE - bytes);
}
data->bytes_read += (off_t) bytes;
if (data->bytes_read >= data->size) {
return 0;
} else {
return 1;
}
}
static
off_t lf_get_size(struct iso_file_src *src)
{
struct local_file_data *data;
assert(src);
data = (struct local_file_data*) src->data;
return data->size;
}
static
void lf_free_data(struct iso_file_src *src)
{
struct local_file_data *data;
data = (struct local_file_data*) src->data;
free(data->path);
free(data);
}
struct iso_file_src*
iso_file_src_from_path(const char *path)
{
struct stat info;
struct iso_file_src *src;
struct local_file_data *data;
assert(path);
if (lstat(path, &info) < 0) {
iso_msg_fatal(LIBISO_FILE_DOESNT_EXIST, "File doesn't exist");
return NULL;
}
if (access(path, R_OK) < 0) {
iso_msg_fatal(LIBISO_FILE_NO_READ_ACCESS, "No read access");
return NULL;
}
data = malloc(sizeof(struct local_file_data));
if (!data)
return NULL;
src = malloc(sizeof(struct iso_file_src));
if (!src) {
free(data);
return NULL;
}
data->fd = -1;
data->path = strdup(path);
data->size = info.st_size;
src->open = lf_open;
src->close = lf_close;
src->read_block = lf_read_block;
src->get_size = lf_get_size;
src->free_data = lf_free_data;
src->data = data;
return src;
}
/*
* ==========================================================================
* B) FILE SRC FOR PREVIOUS IMAGE FILES
* ==========================================================================
*/
struct prev_img_file_data {
int block; /* block where image begins */
off_t size; /* file size */
int nblocks; /* file size in blocks */
int current; /* last block read from file */
int error;
struct data_source *src; /* source for reading from previous image */
};
static
int pi_open(struct iso_file_src *src)
{
struct prev_img_file_data *data;
assert(src);
data = (struct prev_img_file_data*) src->data;
data->current = data->block;
data->error = 0;
return 1;
}
static
void pi_close(struct iso_file_src *src)
{
/* nothing needed */
return;
}
static
int pi_read_block(struct iso_file_src *src, unsigned char *buffer)
{
int res;
struct prev_img_file_data *data;
assert(src);
assert(buffer);
data = (struct prev_img_file_data*) src->data;
if (data->current >= data->block + data->nblocks) {
return 0;
}
if (data->error) {
memset(buffer, 0, BLOCK_SIZE);
data->current++;
return -2;
}
res = data->src->read_block(data->src, data->current++, buffer);
if (res < 0) {
iso_msg_sorry(LIBISO_CANT_READ_IMG,
"Problem reading file from previous image");
/* fill buffer with 0s and return */
memset(buffer, 0, BLOCK_SIZE);
return -1;
}
if (data->current >= data->block + data->nblocks) {
return 0;
} else {
return 1;
}
}
static
off_t pi_get_size(struct iso_file_src *src)
{
struct prev_img_file_data *data;
assert(src);
data = (struct prev_img_file_data*) src->data;
return data->size;
}
static
void pi_free_data(struct iso_file_src *src)
{
free(src->data);
}
struct iso_file_src*
iso_file_src_from_prev_img(struct data_source* data_src, int block, off_t size)
{
struct iso_file_src *src;
struct prev_img_file_data *data;
data = malloc(sizeof(struct prev_img_file_data));
if (!data)
return NULL;
src = malloc(sizeof(struct iso_file_src));
if (!src) {
free(data);
return NULL;
}
data->block = block;
data->size = size;
data->nblocks = div_up(size, BLOCK_SIZE);
data->src = data_src;
src->open = pi_open;
src->close = pi_close;
src->read_block = pi_read_block;
src->get_size = pi_get_size;
src->free_data = pi_free_data;
src->data = data;
return src;
}