100 lines
3.2 KiB
C++
100 lines
3.2 KiB
C++
|
/*
|
||
|
|
* Copyright (C) 2016 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 <cutils/android_get_control_file.h>
|
||
|
|
|
||
|
|
#include <ctype.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <limits.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <sys/stat.h>
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
#include <string>
|
||
|
|
|
||
|
|
#include <android-base/file.h>
|
||
|
|
#include <android-base/stringprintf.h>
|
||
|
|
|
||
|
|
#include "android_get_control_env.h"
|
||
|
|
|
||
|
|
int __android_get_control_from_env(const char* prefix, const char* name) {
|
||
|
|
if (!prefix || !name) return -1;
|
||
|
|
|
||
|
|
char *key = NULL;
|
||
|
|
if (asprintf(&key, "%s%s", prefix, name) < 0) return -1;
|
||
|
|
if (!key) return -1;
|
||
|
|
|
||
|
|
char *cp = key;
|
||
|
|
while (*cp) {
|
||
|
|
if (!isalnum(*cp)) *cp = '_';
|
||
|
|
++cp;
|
||
|
|
}
|
||
|
|
|
||
|
|
const char* val = getenv(key);
|
||
|
|
free(key);
|
||
|
|
if (!val) return -1;
|
||
|
|
|
||
|
|
errno = 0;
|
||
|
|
long fd = strtol(val, NULL, 10);
|
||
|
|
if (errno) return -1;
|
||
|
|
|
||
|
|
// Since we are inheriting an fd, it could legitimately exceed _SC_OPEN_MAX
|
||
|
|
if ((fd < 0) || (fd > INT_MAX)) return -1;
|
||
|
|
|
||
|
|
// Still open?
|
||
|
|
if (TEMP_FAILURE_RETRY(fcntl(fd, F_GETFD)) < 0) return -1;
|
||
|
|
|
||
|
|
return static_cast<int>(fd);
|
||
|
|
}
|
||
|
|
|
||
|
|
int android_get_control_file(const char* path) {
|
||
|
|
std::string given_path;
|
||
|
|
if (!android::base::Realpath(path, &given_path)) return -1;
|
||
|
|
|
||
|
|
// Try path, then realpath(path), as keys to get the fd from env.
|
||
|
|
auto fd = __android_get_control_from_env(ANDROID_FILE_ENV_PREFIX, path);
|
||
|
|
if (fd < 0) {
|
||
|
|
fd = __android_get_control_from_env(ANDROID_FILE_ENV_PREFIX, given_path.c_str());
|
||
|
|
if (fd < 0) return fd;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Find file path from /proc and make sure it is correct
|
||
|
|
auto proc = android::base::StringPrintf("/proc/self/fd/%d", fd);
|
||
|
|
std::string fd_path;
|
||
|
|
if (!android::base::Realpath(proc, &fd_path)) return -1;
|
||
|
|
|
||
|
|
if (given_path != fd_path) return -1;
|
||
|
|
// It is what we think it is
|
||
|
|
|
||
|
|
return fd;
|
||
|
|
}
|