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 #undef _FORTIFY_SOURCE
30
31 #include <errno.h>
32 #include <fcntl.h>
33 #include <stdarg.h>
34 #include <sys/resource.h>
35 #include <sys/types.h>
36 #include <sys/uio.h>
37 #include <sys/vfs.h>
38 #include <unistd.h>
39
40 #include "private/bionic_fdtrack.h"
41
42 #if defined(__LP64__)
43 #error This code is only needed on 32-bit systems!
44 #endif
45
46 // System calls we need.
47 extern "C" int __llseek(int, unsigned long, unsigned long, off64_t*, int);
48 extern "C" int __preadv64(int, const struct iovec*, int, long, long);
49 extern "C" int __pwritev64(int, const struct iovec*, int, long, long);
50
51 // For lseek64 we need to use the llseek system call which splits the off64_t in two and
52 // returns the off64_t result via a pointer because 32-bit kernels can't return 64-bit results.
lseek64(int fd,off64_t off,int whence)53 off64_t lseek64(int fd, off64_t off, int whence) {
54 off64_t result;
55 unsigned long off_hi = static_cast<unsigned long>(off >> 32);
56 unsigned long off_lo = static_cast<unsigned long>(off);
57 if (__llseek(fd, off_hi, off_lo, &result, whence) < 0) {
58 return -1;
59 }
60 return result;
61 }
62
63 // There is no pread for 32-bit off_t, so we need to widen and call pread64.
pread(int fd,void * buf,size_t byte_count,off_t offset)64 ssize_t pread(int fd, void* buf, size_t byte_count, off_t offset) {
65 return pread64(fd, buf, byte_count, static_cast<off64_t>(offset));
66 }
67
68 // There is no pwrite for 32-bit off_t, so we need to widen and call pwrite64.
pwrite(int fd,const void * buf,size_t byte_count,off_t offset)69 ssize_t pwrite(int fd, const void* buf, size_t byte_count, off_t offset) {
70 return pwrite64(fd, buf, byte_count, static_cast<off64_t>(offset));
71 }
72
73 // On LP32, there is no off_t preadv/pwritev, and even the 64-bit preadv/pwritev
74 // don't use off64_t (see SYSCALLS.TXT for more). Here, this means that we need
75 // to implement all four functions because the two system calls don't match any
76 // of the userspace functions. Unlike llseek, the pair is split lo-hi, not hi-lo.
preadv(int fd,const struct iovec * ios,int count,off_t offset)77 ssize_t preadv(int fd, const struct iovec* ios, int count, off_t offset) {
78 return preadv64(fd, ios, count, offset);
79 }
preadv64(int fd,const struct iovec * ios,int count,off64_t offset)80 ssize_t preadv64(int fd, const struct iovec* ios, int count, off64_t offset) {
81 return __preadv64(fd, ios, count, offset, offset >> 32);
82 }
pwritev(int fd,const struct iovec * ios,int count,off_t offset)83 ssize_t pwritev(int fd, const struct iovec* ios, int count, off_t offset) {
84 return pwritev64(fd, ios, count, offset);
85 }
pwritev64(int fd,const struct iovec * ios,int count,off64_t offset)86 ssize_t pwritev64(int fd, const struct iovec* ios, int count, off64_t offset) {
87 return __pwritev64(fd, ios, count, offset, offset >> 32);
88 }
89
90 // There is no fallocate for 32-bit off_t, so we need to widen and call fallocate64.
fallocate(int fd,int mode,off_t offset,off_t length)91 int fallocate(int fd, int mode, off_t offset, off_t length) {
92 return fallocate64(fd, mode, static_cast<off64_t>(offset), static_cast<off64_t>(length));
93 }
94
95 // There is no getrlimit64 system call, so we need to use prlimit64.
getrlimit64(int resource,rlimit64 * limits64)96 int getrlimit64(int resource, rlimit64* limits64) {
97 return prlimit64(0, resource, nullptr, limits64);
98 }
99
100 // There is no setrlimit64 system call, so we need to use prlimit64.
setrlimit64(int resource,const rlimit64 * limits64)101 int setrlimit64(int resource, const rlimit64* limits64) {
102 return prlimit64(0, resource, limits64, nullptr);
103 }
104
105 // There is no prlimit system call, so we need to use prlimit64.
prlimit(pid_t pid,int resource,const rlimit * n32,rlimit * o32)106 int prlimit(pid_t pid, int resource, const rlimit* n32, rlimit* o32) {
107 rlimit64 n64;
108 if (n32 != nullptr) {
109 n64.rlim_cur = (n32->rlim_cur == RLIM_INFINITY) ? RLIM64_INFINITY : n32->rlim_cur;
110 n64.rlim_max = (n32->rlim_max == RLIM_INFINITY) ? RLIM64_INFINITY : n32->rlim_max;
111 }
112
113 rlimit64 o64;
114 int result = prlimit64(pid, resource,
115 (n32 != nullptr) ? &n64 : nullptr,
116 (o32 != nullptr) ? &o64 : nullptr);
117 if (result != -1 && o32 != nullptr) {
118 o32->rlim_cur = (o64.rlim_cur == RLIM64_INFINITY) ? RLIM_INFINITY : o64.rlim_cur;
119 o32->rlim_max = (o64.rlim_max == RLIM64_INFINITY) ? RLIM_INFINITY : o64.rlim_max;
120 }
121 return result;
122 }
123