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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 #define DEBUG false
     17 #include "Log.h"
     18 
     19 #include "incidentd_util.h"
     20 
     21 #include <sys/prctl.h>
     22 #include <wait.h>
     23 
     24 #include "section_list.h"
     25 
     26 namespace android {
     27 namespace os {
     28 namespace incidentd {
     29 
     30 using namespace android::base;
     31 
     32 const Privacy* get_privacy_of_section(int id) {
     33     int l = 0;
     34     int r = PRIVACY_POLICY_COUNT - 1;
     35     while (l <= r) {
     36         int mid = (l + r) >> 1;
     37         const Privacy* p = PRIVACY_POLICY_LIST[mid];
     38 
     39         if (p->field_id < (uint32_t)id) {
     40             l = mid + 1;
     41         } else if (p->field_id > (uint32_t)id) {
     42             r = mid - 1;
     43         } else {
     44             return p;
     45         }
     46     }
     47     return NULL;
     48 }
     49 
     50 // ================================================================================
     51 Fpipe::Fpipe() : mRead(), mWrite() {}
     52 
     53 Fpipe::~Fpipe() { close(); }
     54 
     55 bool Fpipe::close() {
     56     mRead.reset();
     57     mWrite.reset();
     58     return true;
     59 }
     60 
     61 bool Fpipe::init() { return Pipe(&mRead, &mWrite); }
     62 
     63 unique_fd& Fpipe::readFd() { return mRead; }
     64 
     65 unique_fd& Fpipe::writeFd() { return mWrite; }
     66 
     67 pid_t fork_execute_cmd(char* const argv[], Fpipe* input, Fpipe* output) {
     68     // fork used in multithreaded environment, avoid adding unnecessary code in child process
     69     pid_t pid = fork();
     70     if (pid == 0) {
     71         if (input != NULL && (TEMP_FAILURE_RETRY(dup2(input->readFd().get(), STDIN_FILENO)) < 0 ||
     72                               !input->close())) {
     73             ALOGW("Failed to dup2 stdin.");
     74             _exit(EXIT_FAILURE);
     75         }
     76         if (TEMP_FAILURE_RETRY(dup2(output->writeFd().get(), STDOUT_FILENO)) < 0 ||
     77             !output->close()) {
     78             ALOGW("Failed to dup2 stdout.");
     79             _exit(EXIT_FAILURE);
     80         }
     81         /* make sure the child dies when incidentd dies */
     82         prctl(PR_SET_PDEATHSIG, SIGKILL);
     83         execvp(argv[0], argv);
     84         _exit(errno);  // always exits with failure if any
     85     }
     86     // close the fds used in child process.
     87     if (input != NULL) input->readFd().reset();
     88     output->writeFd().reset();
     89     return pid;
     90 }
     91 
     92 // ================================================================================
     93 const char** varargs(const char* first, va_list rest) {
     94     va_list copied_rest;
     95     int numOfArgs = 1;  // first is already count.
     96 
     97     va_copy(copied_rest, rest);
     98     while (va_arg(copied_rest, const char*) != NULL) {
     99         numOfArgs++;
    100     }
    101     va_end(copied_rest);
    102 
    103     // allocate extra 1 for NULL terminator
    104     const char** ret = (const char**)malloc(sizeof(const char*) * (numOfArgs + 1));
    105     ret[0] = first;
    106     for (int i = 1; i < numOfArgs; i++) {
    107         const char* arg = va_arg(rest, const char*);
    108         ret[i] = arg;
    109     }
    110     ret[numOfArgs] = NULL;
    111     return ret;
    112 }
    113 
    114 // ================================================================================
    115 const uint64_t NANOS_PER_SEC = 1000000000;
    116 uint64_t Nanotime() {
    117     timespec ts;
    118     clock_gettime(CLOCK_MONOTONIC, &ts);
    119     return static_cast<uint64_t>(ts.tv_sec * NANOS_PER_SEC + ts.tv_nsec);
    120 }
    121 
    122 // ================================================================================
    123 const int WAIT_MAX = 5;
    124 const struct timespec WAIT_INTERVAL_NS = {0, 200 * 1000 * 1000};
    125 
    126 static status_t statusCode(int status) {
    127     if (WIFSIGNALED(status)) {
    128         VLOG("return by signal: %s", strerror(WTERMSIG(status)));
    129         return -WTERMSIG(status);
    130     } else if (WIFEXITED(status) && WEXITSTATUS(status) > 0) {
    131         VLOG("return by exit: %s", strerror(WEXITSTATUS(status)));
    132         return -WEXITSTATUS(status);
    133     }
    134     return NO_ERROR;
    135 }
    136 
    137 status_t kill_child(pid_t pid) {
    138     int status;
    139     VLOG("try to kill child process %d", pid);
    140     kill(pid, SIGKILL);
    141     if (waitpid(pid, &status, 0) == -1) return -1;
    142     return statusCode(status);
    143 }
    144 
    145 status_t wait_child(pid_t pid) {
    146     int status;
    147     bool died = false;
    148     // wait for child to report status up to 1 seconds
    149     for (int loop = 0; !died && loop < WAIT_MAX; loop++) {
    150         if (waitpid(pid, &status, WNOHANG) == pid) died = true;
    151         // sleep for 0.2 second
    152         nanosleep(&WAIT_INTERVAL_NS, NULL);
    153     }
    154     if (!died) return kill_child(pid);
    155     return statusCode(status);
    156 }
    157 
    158 }  // namespace incidentd
    159 }  // namespace os
    160 }  // namespace android
    161