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