uclibc-ng/libc/sysdeps/linux/common/pread_write.c

/* vi: set sw=4 ts=4: */
/*
 * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
 *
 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
 */
/*
 * Based in part on the files
 *		./sysdeps/unix/sysv/linux/pwrite.c,
 *		./sysdeps/unix/sysv/linux/pread.c,
 *		sysdeps/posix/pread.c
 *		sysdeps/posix/pwrite.c
 * from GNU libc 2.2.5, but reworked considerably...
 */

#include <sys/syscall.h>
#include <unistd.h>
#include <stdint.h>
#include <endian.h>

extern __typeof(pread) __libc_pread;
extern __typeof(pwrite) __libc_pwrite;
#ifdef __UCLIBC_HAS_LFS__
extern __typeof(pread64) __libc_pread64;
extern __typeof(pwrite64) __libc_pwrite64;
#endif

#ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
# undef __NR_pread
# define __NR_pread __NR_pread64
#endif

#include <bits/kernel_types.h>

#ifdef __NR_pread

# define __NR___syscall_pread __NR_pread
static __inline__ _syscall5(ssize_t, __syscall_pread, int, fd, void *, buf,
		size_t, count, off_t, offset_hi, off_t, offset_lo)

ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset)
{
	return __syscall_pread(fd, buf, count, __LONG_LONG_PAIR(offset >> 31, offset));
}
weak_alias(__libc_pread,pread)

# ifdef __UCLIBC_HAS_LFS__
ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
{
	uint32_t low = offset & 0xffffffff;
	uint32_t high = offset >> 32;
	return __syscall_pread(fd, buf, count, __LONG_LONG_PAIR(high, low));
}
weak_alias(__libc_pread64,pread64)
# endif /* __UCLIBC_HAS_LFS__  */

#endif /* __NR_pread */

#ifdef __NR_pwrite64             /* Newer kernels renamed but it's the same.  */
# undef __NR_pwrite
# define __NR_pwrite __NR_pwrite64
#endif

#ifdef __NR_pwrite

# define __NR___syscall_pwrite __NR_pwrite
static __inline__ _syscall5(ssize_t, __syscall_pwrite, int, fd, const void *, buf,
		size_t, count, off_t, offset_hi, off_t, offset_lo)

ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
{
	return __syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR(offset >> 31, offset));
}
weak_alias(__libc_pwrite,pwrite)

# ifdef __UCLIBC_HAS_LFS__
ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
{
	uint32_t low = offset & 0xffffffff;
	uint32_t high = offset >> 32;
	return __syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR(high, low));
}
weak_alias(__libc_pwrite64,pwrite64)
# endif /* __UCLIBC_HAS_LFS__  */
#endif /* __NR_pwrite */