mirror of https://github.com/ventoy/Ventoy.git
349 lines
7.7 KiB
C
349 lines
7.7 KiB
C
/******************************************************************************
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* vtoy_fuse_iso.c
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*
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* Copyright (c) 2020, longpanda <admin@ventoy.net>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#define FUSE_USE_VERSION 26
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#include <fuse.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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typedef unsigned int uint32_t;
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typedef struct dmtable_entry
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{
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uint32_t isoSector;
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uint32_t sectorNum;
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unsigned long long diskSector;
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}dmtable_entry;
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#define MAX_ENTRY_NUM (1024 * 1024 / sizeof(dmtable_entry))
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static int verbose = 0;
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#define debug(fmt, ...) if(verbose) printf(fmt, ##__VA_ARGS__)
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static int g_disk_fd = -1;
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static uint64_t g_iso_file_size;
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static char g_mnt_point[512];
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static char g_iso_file_name[512];
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static dmtable_entry *g_disk_entry_list = NULL;
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static int g_disk_entry_num = 0;
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static int ventoy_iso_getattr(const char *path, struct stat *statinfo)
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{
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int ret = -ENOENT;
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if (path && statinfo)
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{
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memset(statinfo, 0, sizeof(struct stat));
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if (path[0] == '/' && path[1] == 0)
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{
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statinfo->st_mode = S_IFDIR | 0755;
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statinfo->st_nlink = 2;
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ret = 0;
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}
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else if (strcmp(path, g_iso_file_name) == 0)
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{
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statinfo->st_mode = S_IFREG | 0444;
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statinfo->st_nlink = 1;
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statinfo->st_size = g_iso_file_size;
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ret = 0;
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}
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}
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return ret;
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}
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static int ventoy_iso_readdir
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(
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const char *path,
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void *buf,
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fuse_fill_dir_t filler,
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off_t offset,
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struct fuse_file_info *file
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)
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{
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(void)offset;
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(void)file;
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if (path[0] != '/' || path[1] != 0)
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{
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return -ENOENT;
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}
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filler(buf, ".", NULL, 0);
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filler(buf, "..", NULL, 0);
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filler(buf, g_iso_file_name + 1, NULL, 0);
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return 0;
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}
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static int ventoy_iso_open(const char *path, struct fuse_file_info *file)
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{
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if (strcmp(path, g_iso_file_name) != 0)
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{
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return -ENOENT;
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}
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if ((file->flags & 3) != O_RDONLY)
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{
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return -EACCES;
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}
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return 0;
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}
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static int ventoy_read_iso_sector(uint32_t sector, uint32_t num, char *buf)
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{
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uint32_t i = 0;
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uint32_t leftSec = 0;
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uint32_t readSec = 0;
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off_t offset = 0;
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dmtable_entry *entry = NULL;
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for (i = 0; i < g_disk_entry_num && num > 0; i++)
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{
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entry = g_disk_entry_list + i;
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if (sector >= entry->isoSector && sector < entry->isoSector + entry->sectorNum)
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{
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offset = (entry->diskSector + (sector - entry->isoSector)) * 512;
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leftSec = entry->sectorNum - (sector - entry->isoSector);
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readSec = (leftSec > num) ? num : leftSec;
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pread(g_disk_fd, buf, readSec * 512, offset);
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sector += readSec;
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buf += readSec * 512;
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num -= readSec;
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}
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}
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return 0;
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}
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static int ventoy_iso_read
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(
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const char *path, char *buf,
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size_t size, off_t offset,
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struct fuse_file_info *file
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)
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{
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uint32_t mod = 0;
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uint32_t align = 0;
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uint32_t sector = 0;
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uint32_t number = 0;
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size_t leftsize = 0;
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char secbuf[512];
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(void)file;
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if(strcmp(path, g_iso_file_name) != 0)
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{
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return -ENOENT;
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}
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if (offset >= g_iso_file_size)
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{
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return 0;
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}
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if (offset + size > g_iso_file_size)
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{
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size = g_iso_file_size - offset;
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}
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leftsize = size;
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sector = offset / 512;
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mod = offset % 512;
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if (mod > 0)
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{
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align = 512 - mod;
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ventoy_read_iso_sector(sector, 1, secbuf);
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if (leftsize > align)
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{
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memcpy(buf, secbuf + mod, align);
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buf += align;
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offset += align;
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sector++;
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leftsize -= align;
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}
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else
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{
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memcpy(buf, secbuf + mod, leftsize);
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return size;
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}
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}
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number = leftsize / 512;
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ventoy_read_iso_sector(sector, number, buf);
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buf += number * 512;
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mod = leftsize % 512;
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if (mod > 0)
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{
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ventoy_read_iso_sector(sector + number, 1, secbuf);
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memcpy(buf, secbuf, mod);
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}
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return size;
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}
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static struct fuse_operations ventoy_op =
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{
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.getattr = ventoy_iso_getattr,
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.readdir = ventoy_iso_readdir,
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.open = ventoy_iso_open,
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.read = ventoy_iso_read,
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};
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static int ventoy_parse_dmtable(const char *filename)
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{
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FILE *fp = NULL;
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char diskname[128] = {0};
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char line[256] = {0};
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dmtable_entry *entry= g_disk_entry_list;
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fp = fopen(filename, "r");
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if (NULL == fp)
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{
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printf("Failed to open file %s\n", filename);
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return 1;
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}
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/* read untill the last line */
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while (fgets(line, sizeof(line), fp) && g_disk_entry_num < MAX_ENTRY_NUM)
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{
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sscanf(line, "%u %u linear %s %llu",
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&entry->isoSector, &entry->sectorNum,
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diskname, &entry->diskSector);
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g_iso_file_size += (uint64_t)entry->sectorNum * 512ULL;
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g_disk_entry_num++;
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entry++;
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}
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fclose(fp);
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if (g_disk_entry_num >= MAX_ENTRY_NUM)
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{
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fprintf(stderr, "ISO file has too many fragments ( more than %u )\n", MAX_ENTRY_NUM);
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return 1;
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}
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debug("iso file size: %llu disk name %s\n", g_iso_file_size, diskname);
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g_disk_fd = open(diskname, O_RDONLY);
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if (g_disk_fd < 0)
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{
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debug("Failed to open %s\n", diskname);
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return 1;
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}
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return 0;
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}
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int main(int argc, char **argv)
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{
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int rc;
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int ch;
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char filename[512] = {0};
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/* Avoid to be killed by systemd */
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if (access("/etc/initrd-release", F_OK) >= 0)
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{
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argv[0][0] = '@';
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}
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g_iso_file_name[0] = '/';
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while ((ch = getopt(argc, argv, "f:s:m:v::t::")) != -1)
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{
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if (ch == 'f')
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{
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strncpy(filename, optarg, sizeof(filename) - 1);
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}
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else if (ch == 'm')
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{
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strncpy(g_mnt_point, optarg, sizeof(g_mnt_point) - 1);
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}
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else if (ch == 's')
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{
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strncpy(g_iso_file_name + 1, optarg, sizeof(g_iso_file_name) - 2);
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}
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else if (ch == 'v')
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{
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verbose = 1;
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}
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else if (ch == 't') // for test
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{
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return 0;
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}
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}
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if (filename[0] == 0)
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{
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fprintf(stderr, "Must input dmsetup table file with -f\n");
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return 1;
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}
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if (g_mnt_point[0] == 0)
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{
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fprintf(stderr, "Must input mount point with -m\n");
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return 1;
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}
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if (g_iso_file_name[1] == 0)
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{
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strncpy(g_iso_file_name + 1, "ventoy.iso", sizeof(g_iso_file_name) - 2);
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}
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debug("ventoy fuse iso: %s %s %s\n", filename, g_iso_file_name, g_mnt_point);
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g_disk_entry_list = malloc(MAX_ENTRY_NUM * sizeof(dmtable_entry));
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if (NULL == g_disk_entry_list)
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{
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return 1;
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}
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rc = ventoy_parse_dmtable(filename);
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if (rc)
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{
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free(g_disk_entry_list);
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return rc;
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}
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argv[1] = g_mnt_point;
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argv[2] = NULL;
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rc = fuse_main(2, argv, &ventoy_op, NULL);
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close(g_disk_fd);
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free(g_disk_entry_list);
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return rc;
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}
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