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/* libcutils/qtaguid.c
**
** Copyright 2011, 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.
*/
// #define LOG_NDEBUG 0
#define LOG_TAG "qtaguid"
#include <cutils/qtaguid.h>
#include <cutils/log.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
static const char* CTRL_PROCPATH = "/proc/net/xt_qtaguid/ctrl";
static const int CTRL_MAX_INPUT_LEN = 128;
static const char *GLOBAL_PACIFIER_PARAM = "/sys/module/xt_qtaguid/parameters/passive";
static const char *TAG_PACIFIER_PARAM = "/sys/module/xt_qtaguid/parameters/tag_tracking_passive";
/*
* One per proccess.
* Once the device is open, this process will have its socket tags tracked.
* And on exit or untimely death, all socket tags will be removed.
* A process can only open /dev/xt_qtaguid once.
* It should not close it unless it is really done with all the socket tags.
* Failure to open it will be visible when socket tagging will be attempted.
*/
static int resTrackFd = -1;
pthread_once_t resTrackInitDone = PTHREAD_ONCE_INIT;
/* Only call once per process. */
void qtaguid_resTrack(void) {
resTrackFd = TEMP_FAILURE_RETRY(open("/dev/xt_qtaguid", O_RDONLY));
if (resTrackFd >=0) {
TEMP_FAILURE_RETRY(fcntl(resTrackFd, F_SETFD, FD_CLOEXEC));
}
}
/*
* Returns:
* 0 on success.
* -errno on failure.
*/
static int write_ctrl(const char *cmd) {
int fd, res, savedErrno;
LOGV("write_ctrl(%s)", cmd);
fd = TEMP_FAILURE_RETRY(open(CTRL_PROCPATH, O_WRONLY));
if (fd < 0) {
return -errno;
}
res = TEMP_FAILURE_RETRY(write(fd, cmd, strlen(cmd)));
if (res < 0) {
savedErrno = errno;
} else {
savedErrno = 0;
}
if (res < 0) {
LOGI("Failed write_ctrl(%s) res=%d errno=%d", cmd, res, savedErrno);
}
close(fd);
return -savedErrno;
}
static int write_param(const char *param_path, const char *value) {
int param_fd;
int res;
param_fd = TEMP_FAILURE_RETRY(open(param_path, O_WRONLY));
if (param_fd < 0) {
return -errno;
}
res = TEMP_FAILURE_RETRY(write(param_fd, value, strlen(value)));
if (res < 0) {
return -errno;
}
close(param_fd);
return 0;
}
int qtaguid_tagSocket(int sockfd, int tag, uid_t uid) {
char lineBuf[CTRL_MAX_INPUT_LEN];
int res;
/* Doing java-land a favor, enforcing "long" */
uint64_t kTag = ((uint64_t)tag << 32) & ~(1LLU<<63);
pthread_once(&resTrackInitDone, qtaguid_resTrack);
snprintf(lineBuf, sizeof(lineBuf), "t %d %llu %d", sockfd, kTag, uid);
LOGV("Tagging socket %d with tag %llx{%u,0} for uid %d", sockfd, kTag, tag, uid);
res = write_ctrl(lineBuf);
if (res < 0) {
LOGI("Tagging socket %d with tag %llx(%d) for uid %d failed errno=%d",
sockfd, kTag, tag, uid, res);
}
return res;
}
int qtaguid_untagSocket(int sockfd) {
char lineBuf[CTRL_MAX_INPUT_LEN];
int res;
LOGV("Untagging socket %d", sockfd);
snprintf(lineBuf, sizeof(lineBuf), "u %d", sockfd);
res = write_ctrl(lineBuf);
if (res < 0) {
LOGI("Untagging socket %d failed errno=%d", sockfd, res);
}
return res;
}
int qtaguid_setCounterSet(int counterSetNum, uid_t uid) {
char lineBuf[CTRL_MAX_INPUT_LEN];
int res;
LOGV("Setting counters to set %d for uid %d", counterSetNum, uid);
snprintf(lineBuf, sizeof(lineBuf), "s %d %d", counterSetNum, uid);
res = write_ctrl(lineBuf);
return res;
}
int qtaguid_deleteTagData(int tag, uid_t uid) {
char lineBuf[CTRL_MAX_INPUT_LEN];
int fd, cnt = 0, res = 0;
uint64_t kTag = (uint64_t)tag << 32;
LOGV("Deleting tag data with tag %llx{%d,0} for uid %d", kTag, tag, uid);
pthread_once(&resTrackInitDone, qtaguid_resTrack);
snprintf(lineBuf, sizeof(lineBuf), "d %llu %d", kTag, uid);
res = write_ctrl(lineBuf);
if (res < 0) {
LOGI("Deleteing tag data with tag %llx/%d for uid %d failed with cnt=%d errno=%d",
kTag, tag, uid, cnt, errno);
}
return res;
}
int qtaguid_setPacifier(int on) {
int param_fd;
int res;
const char *value;
value = on ? "Y" : "N";
if (write_param(GLOBAL_PACIFIER_PARAM, value) < 0) {
return -errno;
}
if (write_param(TAG_PACIFIER_PARAM, value) < 0) {
return -errno;
}
return 0;
}
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