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/* vi: set sw=4 ts=4:
*
* Copyright (C) 2002 by Erik Andersen <andersen@uclibc.org>
* 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...
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Library 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 Library General Public License
* for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <features.h>
#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS != 64
#undef _FILE_OFFSET_BITS
#define _FILE_OFFSET_BITS 64
#endif
#ifndef __USE_LARGEFILE64
# define __USE_LARGEFILE64 1
#endif
/* We absolutely do _NOT_ want interfaces silently
* renamed under us or very bad things will happen... */
#ifdef __USE_FILE_OFFSET64
# undef __USE_FILE_OFFSET64
#endif
#include <errno.h>
#include <sys/types.h>
#include <sys/syscall.h>
#define _XOPEN_SOURCE 500
#include <unistd.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);
#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);
#endif
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;
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 (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);
}
ssize_t __libc_pread(int fd, void *buf, size_t count, __off_t offset)
{
#ifndef __NR_pread
return(__fake_pread_write(fd, buf, count, offset, 0));
#else
ssize_t result;
/* First try the syscall. */
result = __syscall_pread(fd, buf, count, __LONG_LONG_PAIR(0, offset));
/* Bummer. Syscall failed or is missing. Fake it */
if (result == -1 && errno == ENOSYS) {
result = __fake_pread_write(fd, buf, count, offset, 0);
}
#endif
return result;
}
weak_alias (__libc_pread, pread)
ssize_t __libc_pwrite(int fd, const void *buf, size_t count, __off_t offset)
{
#ifndef __NR_pwrite
return(__fake_pread_write(fd, buf, count, offset, 1));
#else
ssize_t result;
/* First try the syscall. */
result = __syscall_pwrite(fd, buf, count, __LONG_LONG_PAIR(0, offset));
/* Bummer. Syscall failed or is missing. Fake it */
if (result == -1 && errno == ENOSYS) {
result = __fake_pread_write(fd, (void*)buf, count, offset, 1);
}
#endif
return result;
}
weak_alias (__libc_pwrite, pwrite)
#if defined __UCLIBC_HAVE_LFS__
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;
}
ssize_t __libc_pread64(int fd, void *buf, size_t count, off64_t offset)
{
#ifndef __NR_pread
return(__fake_pread_write64(fd, buf, count, offset, 0));
#else
ssize_t result;
/* First try the syscall. */
result = __syscall_pread(fd, buf, count,
__LONG_LONG_PAIR((__off_t) (offset >> 32), (__off_t) (offset & 0xffffffff)));
/* Bummer. Syscall failed or is missing. Fake it */
if (result == -1 && errno == ENOSYS) {
result = __fake_pread_write64(fd, buf, count, offset, 0);
}
return result;
#endif
}
weak_alias (__libc_pread64, pread64)
ssize_t __libc_pwrite64(int fd, const void *buf, size_t count, off64_t offset)
{
#ifndef __NR_pwrite
return(__fake_pread_write64(fd, (void*)buf, count, offset, 1));
#else
ssize_t result;
/* First try the syscall. */
result = __syscall_pwrite(fd, buf, count,
__LONG_LONG_PAIR((__off_t) (offset >> 32), (__off_t) (offset & 0xffffffff)));
/* Bummer. Syscall failed or is missing. Fake it */
if (result == -1 && errno == ENOSYS) {
result = __fake_pread_write64(fd, (void*)buf, count, offset, 1);
}
return result;
#endif
}
weak_alias (__libc_pwrite64, pwrite64)
#endif
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