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/* 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
#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_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 */
#if ! defined __NR_pread || ! defined __NR_pwrite
/* libc_hidden_proto(read) */
/* libc_hidden_proto(write) */
/* libc_hidden_proto(lseek) */
static ssize_t __fake_pread_write(int fd, void *buf,
size_t count, off_t offset, int do_pwrite)
{
int save_errno;
ssize_t result;
off_t old_offset;
/* Since we must not change the file pointer preserve the
* value so that we can restore it later. */
if ((old_offset=lseek(fd, 0, SEEK_CUR)) == (off_t) -1)
return -1;
/* Set to wanted position. */
if (lseek(fd, offset, SEEK_SET) == (off_t) -1)
return -1;
if (do_pwrite == 1) {
/* Write the data. */
result = write(fd, buf, count);
} else {
/* Read the data. */
result = read(fd, buf, count);
}
/* Now we have to restore the position. If this fails we
* have to return this as an error. */
save_errno = errno;
if (lseek(fd, old_offset, SEEK_SET) == (off_t) -1)
{
if (result == -1)
__set_errno(save_errno);
return -1;
}
__set_errno(save_errno);
return(result);
}
# ifdef __UCLIBC_HAS_LFS__
/* libc_hidden_proto(lseek64) */
static ssize_t __fake_pread_write64(int fd, void *buf,
size_t count, off64_t offset, int do_pwrite)
{
int save_errno;
ssize_t result;
off64_t old_offset;
/* Since we must not change the file pointer preserve the
* value so that we can restore it later. */
if ((old_offset=lseek64(fd, 0, SEEK_CUR)) == (off64_t) -1)
return -1;
/* Set to wanted position. */
if (lseek64(fd, offset, SEEK_SET) == (off64_t) -1)
return -1;
if (do_pwrite == 1) {
/* Write the data. */
result = write(fd, buf, count);
} else {
/* Read the data. */
result = read(fd, buf, count);
}
/* Now we have to restore the position. */
save_errno = errno;
if (lseek64(fd, old_offset, SEEK_SET) == (off64_t) -1) {
if (result == -1)
__set_errno (save_errno);
return -1;
}
__set_errno (save_errno);
return result;
}
# endif /* __UCLIBC_HAS_LFS__ */
#endif /* ! defined __NR_pread || ! defined __NR_pwrite */
#ifndef __NR_pread
ssize_t __libc_pread(int fd, void *buf, size_t count, off_t offset)
{
return __fake_pread_write(fd, buf, count, offset, 0);
}
weak_alias(__libc_pread,pread)
# ifdef __UCLIBC_HAS_LFS__
ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
{
return __fake_pread_write64(fd, buf, count, offset, 0);
}
weak_alias(__libc_pread64,pread64)
# endif /* __UCLIBC_HAS_LFS__ */
#endif /* ! __NR_pread */
#ifndef __NR_pwrite
ssize_t __libc_pwrite(int fd, const void *buf, size_t count, off_t offset)
{
/* we won't actually be modifying the buffer,
*just cast it to get rid of warnings */
return __fake_pread_write(fd, (void*)buf, count, offset, 1);
}
weak_alias(__libc_pwrite,pwrite)
# ifdef __UCLIBC_HAS_LFS__
ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
{
return __fake_pread_write64(fd, (void*)buf, count, offset, 1);
}
weak_alias(__libc_pwrite64,pwrite64)
# endif /* __UCLIBC_HAS_LFS__ */
#endif /* ! __NR_pwrite */
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