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 <unistd.h> 30#include <errno.h> 31 32extern "C" int __getcwd(char* buf, size_t size); 33 34char* getcwd(char* buf, size_t size) { 35 // You can't specify size 0 unless you're asking us to allocate for you. 36 if (buf != NULL && size == 0) { 37 errno = EINVAL; 38 return NULL; 39 } 40 41 // Allocate a buffer if necessary. 42 char* allocated_buf = NULL; 43 size_t allocated_size = size; 44 if (buf == NULL) { 45 if (size == 0) { 46 // The Linux kernel won't return more than a page, so translate size 0 to 4KiB. 47 // TODO: if we need to support paths longer than that, we'll have to walk the tree ourselves. 48 allocated_size = getpagesize(); 49 } 50 buf = allocated_buf = static_cast<char*>(malloc(allocated_size)); 51 if (buf == NULL) { 52 // malloc should set errno, but valgrind's malloc wrapper doesn't. 53 errno = ENOMEM; 54 return NULL; 55 } 56 } 57 58 // Ask the kernel to fill our buffer. 59 int rc = __getcwd(buf, allocated_size); 60 if (rc == -1) { 61 free(allocated_buf); 62 // __getcwd set errno. 63 return NULL; 64 } 65 66 // If we allocated a whole page, only return as large an allocation as necessary. 67 if (allocated_buf != NULL) { 68 if (size == 0) { 69 buf = strdup(allocated_buf); 70 free(allocated_buf); 71 } else { 72 buf = allocated_buf; 73 } 74 } 75 76 return buf; 77} 78