104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes/* 204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * Copyright (C) 2008 The Android Open Source Project 304a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * All rights reserved. 404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * 504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * Redistribution and use in source and binary forms, with or without 604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * modification, are permitted provided that the following conditions 704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * are met: 804a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * * Redistributions of source code must retain the above copyright 904a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * notice, this list of conditions and the following disclaimer. 1004a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * * Redistributions in binary form must reproduce the above copyright 1104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * notice, this list of conditions and the following disclaimer in 1204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * the documentation and/or other materials provided with the 1304a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * distribution. 1404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * 1504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 1604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 1704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 1804a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 1904a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 2004a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 2104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 2204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 2304a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 2404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 2504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes * SUCH DAMAGE. 2704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes */ 2804a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 2904a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes#include <unistd.h> 3004a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes#include <errno.h> 3104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 3204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughesextern "C" int __getcwd(char* buf, size_t size); 3304a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 3404a83a48ed89f433c78e31106ed50059764797a0Elliott Hugheschar* getcwd(char* buf, size_t size) { 3504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // You can't specify size 0 unless you're asking us to allocate for you. 3604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (buf != NULL && size == 0) { 3704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes errno = EINVAL; 3804a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes return NULL; 3904a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 4004a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 4104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // Allocate a buffer if necessary. 4204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes char* allocated_buf = NULL; 43156da966214957c5616a0b83cc84686eedfc4e31Elliott Hughes size_t allocated_size = size; 4404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (buf == NULL) { 4504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (size == 0) { 4604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // The Linux kernel won't return more than a page, so translate size 0 to 4KiB. 4704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // TODO: if we need to support paths longer than that, we'll have to walk the tree ourselves. 48156da966214957c5616a0b83cc84686eedfc4e31Elliott Hughes allocated_size = getpagesize(); 4904a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 50c4d1fecc105063e68a5090a6900b63d1b9a24287Elliott Hughes buf = allocated_buf = static_cast<char*>(malloc(allocated_size)); 5104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (buf == NULL) { 52156da966214957c5616a0b83cc84686eedfc4e31Elliott Hughes // malloc should set errno, but valgrind's malloc wrapper doesn't. 53156da966214957c5616a0b83cc84686eedfc4e31Elliott Hughes errno = ENOMEM; 5404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes return NULL; 5504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 5604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 5704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 5804a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // Ask the kernel to fill our buffer. 59156da966214957c5616a0b83cc84686eedfc4e31Elliott Hughes int rc = __getcwd(buf, allocated_size); 6004a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (rc == -1) { 6104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes free(allocated_buf); 6204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // __getcwd set errno. 6304a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes return NULL; 6404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 6504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 6604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes // If we allocated a whole page, only return as large an allocation as necessary. 6704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (allocated_buf != NULL) { 6804a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes if (size == 0) { 6904a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes buf = strdup(allocated_buf); 7004a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes free(allocated_buf); 7104a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } else { 7204a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes buf = allocated_buf; 7304a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 7404a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes } 7504a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes 7604a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes return buf; 7704a83a48ed89f433c78e31106ed50059764797a0Elliott Hughes} 78