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/*
* libhfs - library for reading and writing Macintosh HFS volumes
* Copyright (C) 1996, 1997 Robert Leslie
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: unix.c,v 1.13 1997/11/05 05:31:25 rob Exp $
*/
# ifdef HAVE_CONFIG_H
# include "config.h"
# endif
# ifdef HAVE_FCNTL_H
# include <fcntl.h>
# else
int open(const char *, int, ...);
int fcntl(int, int, ...);
# endif
# ifdef HAVE_UNISTD_H
# include <unistd.h>
# else
int close(int);
off_t lseek(int, off_t, int);
ssize_t read(int, void *, size_t);
ssize_t write(int, const char *, size_t);
int stat(const char *, struct stat *);
int fstat(int, struct stat *);
# endif
# include <errno.h>
# include <sys/stat.h>
# include "libhfs.h"
# include "os.h"
/*
* NAME: os->open()
* DESCRIPTION: open and lock a new descriptor from the given path and mode
*/
int os_open(void **priv, const char *path, int mode)
{
int fd;
struct flock lock;
switch (mode)
{
case HFS_MODE_RDONLY:
mode = O_RDONLY;
break;
case HFS_MODE_RDWR:
default:
mode = O_RDWR;
break;
}
fd = open(path, mode);
if (fd == -1)
ERROR(errno, "error opening medium");
/* lock descriptor against concurrent access */
lock.l_type = (mode == O_RDONLY) ? F_RDLCK : F_WRLCK;
lock.l_start = 0;
lock.l_whence = SEEK_SET;
lock.l_len = 0;
if (fcntl(fd, F_SETLK, &lock) == -1 &&
(errno == EACCES || errno == EAGAIN))
ERROR(EAGAIN, "unable to obtain lock for medium");
*priv = (void *) fd;
return 0;
fail:
if (fd != -1)
close(fd);
return -1;
}
/*
* NAME: os->close()
* DESCRIPTION: close an open descriptor
*/
int os_close(void **priv)
{
int fd = (int) *priv;
*priv = (void *) -1;
if (close(fd) == -1)
ERROR(errno, "error closing medium");
return 0;
fail:
return -1;
}
/*
* NAME: os->same()
* DESCRIPTION: return 1 iff path is same as the open descriptor
*/
int os_same(void **priv, const char *path)
{
int fd = (int) *priv;
struct stat fdev, dev;
if (fstat(fd, &fdev) == -1 ||
stat(path, &dev) == -1)
ERROR(errno, "can't get path information");
return fdev.st_dev == dev.st_dev &&
fdev.st_ino == dev.st_ino;
fail:
return -1;
}
/*
* NAME: os->seek()
* DESCRIPTION: set a descriptor's seek pointer
*/
long os_seek(void **priv, long offset, int from)
{
long result;
switch (from)
{
case HFS_SEEK_CUR:
from = SEEK_CUR;
break;
case HFS_SEEK_END:
from = SEEK_END;
break;
case HFS_SEEK_SET:
default:
from = SEEK_SET;
break;
}
result = lseek((int) *priv, offset, from);
if (result == -1)
ERROR(errno, "error seeking medium");
return result;
fail:
return -1;
}
/*
* NAME: os->read()
* DESCRIPTION: read bytes from an open descriptor
*/
long os_read(void **priv, void *buf, unsigned long len)
{
long result;
result = read((int) *priv, buf, len);
if (result == -1)
ERROR(errno, "error reading from medium");
return result;
fail:
return -1;
}
/*
* NAME: os->write()
* DESCRIPTION: write bytes to an open descriptor
*/
long os_write(void **priv, const void *buf, unsigned long len)
{
long result;
result = write((int) *priv, buf, len);
if (result == -1)
ERROR(errno, "error writing to medium");
return result;
fail:
return -1;
}
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