platform_system_core/libcutils/native_handle.cpp
Martijn Coenen 20ac1203a3 Export maximum number of fds/ints in a native_handle.
So we can deserialize it consisently and safely.

Bug: 120084106
Test: builds
Change-Id: I0eafff70d3a7e4d732fe600a0052efb90108208d
2019-01-16 08:55:14 -08:00

93 lines
2.7 KiB
C++

/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <cutils/native_handle.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
native_handle_t* native_handle_init(char* storage, int numFds, int numInts) {
if ((uintptr_t) storage % alignof(native_handle_t)) {
errno = EINVAL;
return NULL;
}
native_handle_t* handle = (native_handle_t*) storage;
handle->version = sizeof(native_handle_t);
handle->numFds = numFds;
handle->numInts = numInts;
return handle;
}
native_handle_t* native_handle_create(int numFds, int numInts) {
if (numFds < 0 || numInts < 0 || numFds > NATIVE_HANDLE_MAX_FDS ||
numInts > NATIVE_HANDLE_MAX_INTS) {
errno = EINVAL;
return NULL;
}
size_t mallocSize = sizeof(native_handle_t) + (sizeof(int) * (numFds + numInts));
native_handle_t* h = static_cast<native_handle_t*>(malloc(mallocSize));
if (h) {
h->version = sizeof(native_handle_t);
h->numFds = numFds;
h->numInts = numInts;
}
return h;
}
native_handle_t* native_handle_clone(const native_handle_t* handle) {
native_handle_t* clone = native_handle_create(handle->numFds, handle->numInts);
if (clone == NULL) return NULL;
for (int i = 0; i < handle->numFds; i++) {
clone->data[i] = dup(handle->data[i]);
if (clone->data[i] == -1) {
clone->numFds = i;
native_handle_close(clone);
native_handle_delete(clone);
return NULL;
}
}
memcpy(&clone->data[handle->numFds], &handle->data[handle->numFds],
sizeof(int) * handle->numInts);
return clone;
}
int native_handle_delete(native_handle_t* h) {
if (h) {
if (h->version != sizeof(native_handle_t)) return -EINVAL;
free(h);
}
return 0;
}
int native_handle_close(const native_handle_t* h) {
if (h->version != sizeof(native_handle_t)) return -EINVAL;
int saved_errno = errno;
const int numFds = h->numFds;
for (int i = 0; i < numFds; ++i) {
close(h->data[i]);
}
errno = saved_errno;
return 0;
}