1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/uio.h>
30
31 // System calls we need.
32 extern "C" int __preadv64(int, const struct iovec*, int, long, long);
33 extern "C" int __preadv64v2(int, const struct iovec*, int, long, long, int);
34 extern "C" int __pwritev64(int, const struct iovec*, int, long, long);
35 extern "C" int __pwritev64v2(int, const struct iovec*, int, long, long, int);
36
37 // There is no 32-bit off_t preadv/pwritev (even on LP32).
38 // To avoid 32-bit ABI issues about which register pairs you're allowed
39 // to pass 64-bit values in, the kernel just takes two `long` arguments --
40 // which are int32_t for LP32, remember -- and stitches them together.
41 // It even does this for LP64, taking a second unused always-zero `long`.
42 // (The first long was int64_t, which is the same as off64_t.)
43 // The pair is split lo-hi (not hi-lo, as llseek is).
44
preadv(int fd,const struct iovec * ios,int count,off_t offset)45 ssize_t preadv(int fd, const struct iovec* ios, int count, off_t offset) {
46 return preadv64(fd, ios, count, offset);
47 }
48
preadv64(int fd,const struct iovec * ios,int count,off64_t offset)49 ssize_t preadv64(int fd, const struct iovec* ios, int count, off64_t offset) {
50 #if defined(__LP64__)
51 return __preadv64(fd, ios, count, offset, 0);
52 #else
53 return __preadv64(fd, ios, count, offset, offset >> 32);
54 #endif
55 }
56
pwritev(int fd,const struct iovec * ios,int count,off_t offset)57 ssize_t pwritev(int fd, const struct iovec* ios, int count, off_t offset) {
58 return pwritev64(fd, ios, count, offset);
59 }
60
pwritev64(int fd,const struct iovec * ios,int count,off64_t offset)61 ssize_t pwritev64(int fd, const struct iovec* ios, int count, off64_t offset) {
62 #if defined(__LP64__)
63 return __pwritev64(fd, ios, count, offset, 0);
64 #else
65 return __pwritev64(fd, ios, count, offset, offset >> 32);
66 #endif
67 }
68
preadv2(int fd,const struct iovec * ios,int count,off_t offset,int flags)69 ssize_t preadv2(int fd, const struct iovec* ios, int count, off_t offset, int flags) {
70 return preadv64v2(fd, ios, count, offset, flags);
71 }
72
preadv64v2(int fd,const struct iovec * ios,int count,off64_t offset,int flags)73 ssize_t preadv64v2(int fd, const struct iovec* ios, int count, off64_t offset, int flags) {
74 #if defined(__LP64__)
75 return __preadv64v2(fd, ios, count, offset, 0, flags);
76 #else
77 return __preadv64v2(fd, ios, count, offset, offset >> 32, flags);
78 #endif
79 }
80
pwritev2(int fd,const struct iovec * ios,int count,off_t offset,int flags)81 ssize_t pwritev2(int fd, const struct iovec* ios, int count, off_t offset, int flags) {
82 return pwritev64v2(fd, ios, count, offset, flags);
83 }
84
pwritev64v2(int fd,const struct iovec * ios,int count,off64_t offset,int flags)85 ssize_t pwritev64v2(int fd, const struct iovec* ios, int count, off64_t offset, int flags) {
86 #if defined(__LP64__)
87 return __pwritev64v2(fd, ios, count, offset, 0, flags);
88 #else
89 return __pwritev64v2(fd, ios, count, offset, offset >> 32, flags);
90 #endif
91 }
92