mirror of
https://github.com/autc04/Retro68.git
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200 lines
4.1 KiB
C
200 lines
4.1 KiB
C
/*
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* libhfs - library for reading and writing Macintosh HFS volumes
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* Copyright (C) 1996-1998 Robert Leslie
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (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,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU 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, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id: unix.c,v 1.8 1998/11/02 22:09:13 rob Exp $
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*/
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# ifdef HAVE_CONFIG_H
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# include "config.h"
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# endif
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# ifdef HAVE_FCNTL_H
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# include <fcntl.h>
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# else
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int open(const char *, int, ...);
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int fcntl(int, int, ...);
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# endif
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# ifdef HAVE_UNISTD_H
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# include <unistd.h>
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# else
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int close(int);
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off_t lseek(int, off_t, int);
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ssize_t read(int, void *, size_t);
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ssize_t write(int, const char *, size_t);
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int stat(const char *, struct stat *);
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int fstat(int, struct stat *);
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# endif
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# include <errno.h>
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# include <sys/stat.h>
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# include "libhfs.h"
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# include "os.h"
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/*
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* NAME: os->open()
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* DESCRIPTION: open and lock a new descriptor from the given path and mode
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*/
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int os_open(void **priv, const char *path, int mode)
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{
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int fd;
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struct flock lock;
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switch (mode)
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{
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case HFS_MODE_RDONLY:
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mode = O_RDONLY;
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break;
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case HFS_MODE_RDWR:
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default:
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mode = O_RDWR;
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break;
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}
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fd = open(path, mode);
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if (fd == -1)
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ERROR(errno, "error opening medium");
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/* lock descriptor against concurrent access */
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lock.l_type = (mode == O_RDONLY) ? F_RDLCK : F_WRLCK;
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lock.l_start = 0;
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lock.l_whence = SEEK_SET;
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lock.l_len = 0;
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if (fcntl(fd, F_SETLK, &lock) == -1 &&
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(errno == EACCES || errno == EAGAIN))
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ERROR(EAGAIN, "unable to obtain lock for medium");
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*priv = (void *) fd;
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return 0;
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fail:
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if (fd != -1)
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close(fd);
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return -1;
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}
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/*
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* NAME: os->close()
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* DESCRIPTION: close an open descriptor
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*/
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int os_close(void **priv)
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{
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int fd = (int) *priv;
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*priv = (void *) -1;
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if (close(fd) == -1)
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ERROR(errno, "error closing medium");
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return 0;
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fail:
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return -1;
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}
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/*
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* NAME: os->same()
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* DESCRIPTION: return 1 iff path is same as the open descriptor
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*/
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int os_same(void **priv, const char *path)
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{
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int fd = (int) *priv;
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struct stat fdev, dev;
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if (fstat(fd, &fdev) == -1 ||
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stat(path, &dev) == -1)
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ERROR(errno, "can't get path information");
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return fdev.st_dev == dev.st_dev &&
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fdev.st_ino == dev.st_ino;
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fail:
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return -1;
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}
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/*
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* NAME: os->seek()
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* DESCRIPTION: set a descriptor's seek pointer (offset in blocks)
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*/
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unsigned long os_seek(void **priv, unsigned long offset)
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{
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int fd = (int) *priv;
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off_t result;
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/* offset == -1 special; seek to last block of device */
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if (offset == (unsigned long) -1)
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result = lseek(fd, 0, SEEK_END);
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else
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result = lseek(fd, offset << HFS_BLOCKSZ_BITS, SEEK_SET);
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if (result == -1)
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ERROR(errno, "error seeking medium");
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return (unsigned long) result >> HFS_BLOCKSZ_BITS;
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fail:
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return -1;
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}
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/*
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* NAME: os->read()
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* DESCRIPTION: read blocks from an open descriptor
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*/
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unsigned long os_read(void **priv, void *buf, unsigned long len)
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{
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int fd = (int) *priv;
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ssize_t result;
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result = read(fd, buf, len << HFS_BLOCKSZ_BITS);
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if (result == -1)
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ERROR(errno, "error reading from medium");
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return (unsigned long) result >> HFS_BLOCKSZ_BITS;
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fail:
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return -1;
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}
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/*
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* NAME: os->write()
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* DESCRIPTION: write blocks to an open descriptor
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*/
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unsigned long os_write(void **priv, const void *buf, unsigned long len)
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{
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int fd = (int) *priv;
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ssize_t result;
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result = write(fd, buf, len << HFS_BLOCKSZ_BITS);
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if (result == -1)
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ERROR(errno, "error writing to medium");
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return (unsigned long) result >> HFS_BLOCKSZ_BITS;
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fail:
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return -1;
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}
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