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 #if defined(__LP64__) 41 #error This code is only needed on 32-bit systems! 42 #endif 43 44 // System calls we need. 45 extern "C" int __fcntl64(int, int, void*); 46 extern "C" int __llseek(int, unsigned long, unsigned long, off64_t*, int); 47 extern "C" int __preadv64(int, const struct iovec*, int, long, long); 48 extern "C" int __pwritev64(int, const struct iovec*, int, long, long); 49 50 // For fcntl we use the fcntl64 system call to signal that we're using struct flock64. 51 int fcntl(int fd, int cmd, ...) { 52 va_list ap; 53 54 va_start(ap, cmd); 55 void* arg = va_arg(ap, void*); 56 va_end(ap); 57 58 return __fcntl64(fd, cmd, arg); 59 } 60 61 // For lseek64 we need to use the llseek system call which splits the off64_t in two and 62 // returns the off64_t result via a pointer because 32-bit kernels can't return 64-bit results. 63 off64_t lseek64(int fd, off64_t off, int whence) { 64 off64_t result; 65 unsigned long off_hi = static_cast<unsigned long>(off >> 32); 66 unsigned long off_lo = static_cast<unsigned long>(off); 67 if (__llseek(fd, off_hi, off_lo, &result, whence) < 0) { 68 return -1; 69 } 70 return result; 71 } 72 73 // There is no pread for 32-bit off_t, so we need to widen and call pread64. 74 ssize_t pread(int fd, void* buf, size_t byte_count, off_t offset) { 75 return pread64(fd, buf, byte_count, static_cast<off64_t>(offset)); 76 } 77 78 // There is no pwrite for 32-bit off_t, so we need to widen and call pwrite64. 79 ssize_t pwrite(int fd, const void* buf, size_t byte_count, off_t offset) { 80 return pwrite64(fd, buf, byte_count, static_cast<off64_t>(offset)); 81 } 82 83 // On LP32, there is no off_t preadv/pwritev, and even the 64-bit preadv/pwritev 84 // don't use off64_t (see SYSCALLS.TXT for more). Here, this means that we need 85 // to implement all four functions because the two system calls don't match any 86 // of the userspace functions. Unlike llseek, the pair is split lo-hi, not hi-lo. 87 ssize_t preadv(int fd, const struct iovec* ios, int count, off_t offset) { 88 return preadv64(fd, ios, count, offset); 89 } 90 ssize_t preadv64(int fd, const struct iovec* ios, int count, off64_t offset) { 91 return __preadv64(fd, ios, count, offset, offset >> 32); 92 } 93 ssize_t pwritev(int fd, const struct iovec* ios, int count, off_t offset) { 94 return pwritev64(fd, ios, count, offset); 95 } 96 ssize_t pwritev64(int fd, const struct iovec* ios, int count, off64_t offset) { 97 return __pwritev64(fd, ios, count, offset, offset >> 32); 98 } 99 100 // There is no fallocate for 32-bit off_t, so we need to widen and call fallocate64. 101 int fallocate(int fd, int mode, off_t offset, off_t length) { 102 return fallocate64(fd, mode, static_cast<off64_t>(offset), static_cast<off64_t>(length)); 103 } 104 105 // There is no getrlimit64 system call, so we need to use prlimit64. 106 int getrlimit64(int resource, rlimit64* limits64) { 107 return prlimit64(0, resource, NULL, limits64); 108 } 109 110 // There is no setrlimit64 system call, so we need to use prlimit64. 111 int setrlimit64(int resource, const rlimit64* limits64) { 112 return prlimit64(0, resource, limits64, NULL); 113 } 114 115 // There is no prlimit system call, so we need to use prlimit64. 116 int prlimit(pid_t pid, int resource, const rlimit* n32, rlimit* o32) { 117 rlimit64 n64; 118 if (n32 != nullptr) { 119 n64.rlim_cur = (n32->rlim_cur == RLIM_INFINITY) ? RLIM64_INFINITY : n32->rlim_cur; 120 n64.rlim_max = (n32->rlim_max == RLIM_INFINITY) ? RLIM64_INFINITY : n32->rlim_max; 121 } 122 123 rlimit64 o64; 124 int result = prlimit64(pid, resource, 125 (n32 != nullptr) ? &n64 : nullptr, 126 (o32 != nullptr) ? &o64 : nullptr); 127 if (result != -1 && o32 != nullptr) { 128 o32->rlim_cur = (o64.rlim_cur == RLIM64_INFINITY) ? RLIM_INFINITY : o64.rlim_cur; 129 o32->rlim_max = (o64.rlim_max == RLIM64_INFINITY) ? RLIM_INFINITY : o64.rlim_max; 130 } 131 return result; 132 } 133
