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/*
* Block device emulated on standard files
*
* Copyright (c) 2017 Christopher Haster
* Distributed under the MIT license
*/
#include "emubd/lfs_emubd.h"
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>
#include <assert.h>
#include <stdbool.h>
// Block device emulated on existing filesystem
int lfs_emubd_create(const struct lfs_config *cfg, const char *path) {
lfs_emubd_t *emu = cfg->context;
emu->cfg.read_size = cfg->read_size;
emu->cfg.prog_size = cfg->prog_size;
emu->cfg.block_size = cfg->block_size;
emu->cfg.block_count = cfg->block_count;
// Allocate buffer for creating children files
size_t pathlen = strlen(path);
emu->path = malloc(pathlen + 1 + LFS_NAME_MAX + 1);
if (!emu->path) {
return -ENOMEM;
}
strcpy(emu->path, path);
emu->path[pathlen] = '/';
emu->child = &emu->path[pathlen+1];
memset(emu->child, '\0', LFS_NAME_MAX+1);
// Create directory if it doesn't exist
int err = mkdir(path, 0777);
if (err && errno != EEXIST) {
return -errno;
}
// Load stats to continue incrementing
snprintf(emu->child, LFS_NAME_MAX, "stats");
FILE *f = fopen(emu->path, "r");
if (!f) {
return -errno;
}
size_t res = fread(&emu->stats, sizeof(emu->stats), 1, f);
if (res < 1) {
return -errno;
}
err = fclose(f);
if (err) {
return -errno;
}
return 0;
}
void lfs_emubd_destroy(const struct lfs_config *cfg) {
lfs_emubd_sync(cfg);
lfs_emubd_t *emu = cfg->context;
free(emu->path);
}
int lfs_emubd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, lfs_size_t size, void *buffer) {
lfs_emubd_t *emu = cfg->context;
uint8_t *data = buffer;
// Check if read is valid
assert(off % cfg->read_size == 0);
assert(size % cfg->read_size == 0);
assert(block < cfg->block_count);
// Zero out buffer for debugging
memset(data, 0, size);
// Read data
snprintf(emu->child, LFS_NAME_MAX, "%x", block);
FILE *f = fopen(emu->path, "rb");
if (!f && errno != ENOENT) {
return -errno;
}
if (f) {
int err = fseek(f, off, SEEK_SET);
if (err) {
return -errno;
}
size_t res = fread(data, 1, size, f);
if (res < size && !feof(f)) {
return -errno;
}
err = fclose(f);
if (err) {
return -errno;
}
}
emu->stats.read_count += 1;
return 0;
}
int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, lfs_size_t size, const void *buffer) {
lfs_emubd_t *emu = cfg->context;
const uint8_t *data = buffer;
// Check if write is valid
assert(off % cfg->prog_size == 0);
assert(size % cfg->prog_size == 0);
assert(block < cfg->block_count);
// Program data
snprintf(emu->child, LFS_NAME_MAX, "%x", block);
FILE *f = fopen(emu->path, "r+b");
if (!f && errno == ENOENT) {
f = fopen(emu->path, "w+b");
if (!f) {
return -errno;
}
}
int err = fseek(f, off, SEEK_SET);
if (err) {
return -errno;
}
size_t res = fwrite(data, 1, size, f);
if (res < size) {
return -errno;
}
err = fclose(f);
if (err) {
return -errno;
}
emu->stats.prog_count += 1;
return 0;
}
int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block) {
lfs_emubd_t *emu = cfg->context;
// Check if erase is valid
assert(block < cfg->block_count);
// Erase the block
snprintf(emu->child, LFS_NAME_MAX, "%x", block);
struct stat st;
int err = stat(emu->path, &st);
if (err && errno != ENOENT) {
return -errno;
}
if (!err && S_ISREG(st.st_mode)) {
int err = unlink(emu->path);
if (err) {
return -errno;
}
}
emu->stats.erase_count += 1;
return 0;
}
int lfs_emubd_sync(const struct lfs_config *cfg) {
lfs_emubd_t *emu = cfg->context;
// Just write out info/stats for later lookup
snprintf(emu->child, LFS_NAME_MAX, "config");
FILE *f = fopen(emu->path, "w");
if (!f) {
return -errno;
}
size_t res = fwrite(&emu->cfg, sizeof(emu->cfg), 1, f);
if (res < 1) {
return -errno;
}
int err = fclose(f);
if (err) {
return -errno;
}
snprintf(emu->child, LFS_NAME_MAX, "stats");
f = fopen(emu->path, "w");
if (!f) {
return -errno;
}
res = fwrite(&emu->stats, sizeof(emu->stats), 1, f);
if (res < 1) {
return -errno;
}
err = fclose(f);
if (err) {
return -errno;
}
return 0;
}
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