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      1 /*
      2  * Copyright (C) 2008 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 
     17 #include <stdio.h>
     18 #include <unistd.h>
     19 #include <errno.h>
     20 #include <string.h>
     21 #include <fcntl.h>
     22 #include <fts.h>
     23 #include <dirent.h>
     24 #include <ctype.h>
     25 #include <pwd.h>
     26 #include <stdlib.h>
     27 #include <poll.h>
     28 #include <sys/stat.h>
     29 #include <signal.h>
     30 
     31 #include <fstream>
     32 #include <unordered_set>
     33 
     34 #include <android-base/file.h>
     35 #include <android-base/parseint.h>
     36 #include <android-base/strings.h>
     37 #include <android-base/stringprintf.h>
     38 #include <android-base/logging.h>
     39 
     40 #include "Process.h"
     41 
     42 using android::base::StringPrintf;
     43 
     44 namespace android {
     45 namespace vold {
     46 
     47 static bool checkMaps(const std::string& path, const std::string& prefix) {
     48     bool found = false;
     49     std::ifstream infile(path);
     50     std::string line;
     51     while (std::getline(infile, line)) {
     52         std::string::size_type pos = line.find('/');
     53         if (pos != std::string::npos) {
     54             line = line.substr(pos);
     55             if (android::base::StartsWith(line, prefix)) {
     56                 LOG(WARNING) << "Found map " << path << " referencing " << line;
     57                 found = true;
     58             }
     59         }
     60     }
     61     return found;
     62 }
     63 
     64 static bool checkSymlink(const std::string& path, const std::string& prefix) {
     65     std::string res;
     66     if (android::base::Readlink(path, &res)) {
     67         if (android::base::StartsWith(res, prefix)) {
     68             LOG(WARNING) << "Found symlink " << path << " referencing " << res;
     69             return true;
     70         }
     71     }
     72     return false;
     73 }
     74 
     75 int KillProcessesWithOpenFiles(const std::string& prefix, int signal) {
     76     std::unordered_set<pid_t> pids;
     77 
     78     auto proc_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/proc"), closedir);
     79     if (!proc_d) {
     80         PLOG(ERROR) << "Failed to open proc";
     81         return -1;
     82     }
     83 
     84     struct dirent* proc_de;
     85     while ((proc_de = readdir(proc_d.get())) != nullptr) {
     86         // We only care about valid PIDs
     87         pid_t pid;
     88         if (proc_de->d_type != DT_DIR) continue;
     89         if (!android::base::ParseInt(proc_de->d_name, &pid)) continue;
     90 
     91         // Look for references to prefix
     92         bool found = false;
     93         auto path = StringPrintf("/proc/%d", pid);
     94         found |= checkMaps(path + "/maps", prefix);
     95         found |= checkSymlink(path + "/cwd", prefix);
     96         found |= checkSymlink(path + "/root", prefix);
     97         found |= checkSymlink(path + "/exe", prefix);
     98 
     99         auto fd_path = path + "/fd";
    100         auto fd_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(fd_path.c_str()), closedir);
    101         if (!fd_d) {
    102             PLOG(WARNING) << "Failed to open " << fd_path;
    103         } else {
    104             struct dirent* fd_de;
    105             while ((fd_de = readdir(fd_d.get())) != nullptr) {
    106                 if (fd_de->d_type != DT_LNK) continue;
    107                 found |= checkSymlink(fd_path + "/" + fd_de->d_name, prefix);
    108             }
    109         }
    110 
    111         if (found) {
    112             pids.insert(pid);
    113         }
    114     }
    115     if (signal != 0) {
    116         for (const auto& pid : pids) {
    117             LOG(WARNING) << "Sending " << strsignal(signal) << " to " << pid;
    118             kill(pid, signal);
    119         }
    120     }
    121     return pids.size();
    122 }
    123 
    124 }  // namespace vold
    125 }  // namespace android
    126