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 <errno.h> 30 #include <malloc.h> 31 #include <string.h> 32 #include <unistd.h> 33 34 extern "C" int __getcwd(char* buf, size_t size); 35 36 char* getcwd(char* buf, size_t size) { 37 // You can't specify size 0 unless you're asking us to allocate for you. 38 if (buf != NULL && size == 0) { 39 errno = EINVAL; 40 return NULL; 41 } 42 43 // Allocate a buffer if necessary. 44 char* allocated_buf = NULL; 45 size_t allocated_size = size; 46 if (buf == NULL) { 47 if (size == 0) { 48 // The Linux kernel won't return more than a page, so translate size 0 to 4KiB. 49 // TODO: if we need to support paths longer than that, we'll have to walk the tree ourselves. 50 allocated_size = getpagesize(); 51 } 52 buf = allocated_buf = static_cast<char*>(malloc(allocated_size)); 53 if (buf == NULL) { 54 // malloc should set errno, but valgrind's malloc wrapper doesn't. 55 errno = ENOMEM; 56 return NULL; 57 } 58 } 59 60 // Ask the kernel to fill our buffer. 61 int rc = __getcwd(buf, allocated_size); 62 if (rc == -1) { 63 free(allocated_buf); 64 // __getcwd set errno. 65 return NULL; 66 } 67 68 // If we allocated a whole page, only return as large an allocation as necessary. 69 if (allocated_buf != NULL) { 70 if (size == 0) { 71 buf = strdup(allocated_buf); 72 free(allocated_buf); 73 } else { 74 buf = allocated_buf; 75 } 76 } 77 78 return buf; 79 } 80
