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/*
* The PCI Library -- Portable interface to pread() and pwrite()
*
* Copyright (c) 1997--2003 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL v2+
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
* We'd like to use pread/pwrite for configuration space accesses, but
* unfortunately it isn't simple at all since all libc's until glibc 2.1
* don't define it.
*/
#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
/* glibc 2.1 or newer -> pread/pwrite supported automatically */
#elif defined(i386) && defined(__GLIBC__)
/* glibc 2.0 on i386 -> call syscalls directly */
#include <asm/unistd.h>
#include <syscall-list.h>
#ifndef SYS_pread
#define SYS_pread 180
#endif
static int pread(unsigned int fd, void *buf, size_t size, loff_t where)
{ return syscall(SYS_pread, fd, buf, size, where); }
#ifndef SYS_pwrite
#define SYS_pwrite 181
#endif
static int pwrite(unsigned int fd, void *buf, size_t size, loff_t where)
{ return syscall(SYS_pwrite, fd, buf, size, where); }
#else
/* In all other cases we use lseek/read/write instead to be safe */
#define make_rw_glue(op) \
static int do_##op(struct pci_dev *d, int fd, void *buf, size_t size, int where) \
{ \
struct pci_access *a = d->access; \
int r; \
if (a->fd_pos != where && lseek(fd, where, SEEK_SET) < 0) \
return -1; \
r = op(fd, buf, size); \
if (r < 0) \
a->fd_pos = -1; \
else \
a->fd_pos = where + r; \
return r; \
}
make_rw_glue(read)
make_rw_glue(write)
#define PCI_HAVE_DO_READ
#endif
#ifndef PCI_HAVE_DO_READ
#define do_read(d,f,b,l,p) pread(f,b,l,p)
#define do_write(d,f,b,l,p) pwrite(f,b,l,p)
#endif
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