79 lines
2.7 KiB
C++
79 lines
2.7 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <errno.h>
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#include <malloc.h>
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#include <string.h>
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#include <unistd.h>
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extern "C" int __getcwd(char* buf, size_t size);
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char* getcwd(char* buf, size_t size) {
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// You can't specify size 0 unless you're asking us to allocate for you.
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if (buf != NULL && size == 0) {
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errno = EINVAL;
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return NULL;
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}
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// Allocate a buffer if necessary.
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char* allocated_buf = NULL;
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size_t allocated_size = size;
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if (buf == NULL) {
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if (size == 0) {
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// The Linux kernel won't return more than a page, so translate size 0 to 4KiB.
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// TODO: if we need to support paths longer than that, we'll have to walk the tree ourselves.
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allocated_size = getpagesize();
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}
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buf = allocated_buf = static_cast<char*>(malloc(allocated_size));
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if (buf == NULL) {
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// malloc should set errno, but valgrind's malloc wrapper doesn't.
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errno = ENOMEM;
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return NULL;
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}
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}
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// Ask the kernel to fill our buffer.
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int rc = __getcwd(buf, allocated_size);
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if (rc == -1) {
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free(allocated_buf);
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// __getcwd set errno.
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return NULL;
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}
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// If we allocated a whole page, only return as large an allocation as necessary.
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if (allocated_buf != NULL) {
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if (size == 0) {
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buf = strdup(allocated_buf);
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free(allocated_buf);
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} else {
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buf = allocated_buf;
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}
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}
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return buf;
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}
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