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      1 /*
      2  * Copyright (C) 2016 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 #define LOG_TAG "incidentd"
     18 
     19 #include "report_directory.h"
     20 
     21 #include <cutils/log.h>
     22 #include <private/android_filesystem_config.h>
     23 #include <utils/String8.h>
     24 
     25 #include <sys/types.h>
     26 #include <sys/stat.h>
     27 #include <dirent.h>
     28 #include <libgen.h>
     29 #include <unistd.h>
     30 
     31 #include <vector>
     32 
     33 using namespace android;
     34 using namespace std;
     35 
     36 status_t
     37 create_directory(const char* directory)
     38 {
     39     struct stat st;
     40     status_t err = NO_ERROR;
     41     char* dir = strdup(directory);
     42 
     43     // Skip first slash
     44     char* d = dir + 1;
     45 
     46     // Create directories, assigning them to the system user
     47     bool last = false;
     48     while (!last) {
     49         d = strchr(d, '/');
     50         if (d != NULL) {
     51             *d = '\0';
     52         } else {
     53             last = true;
     54         }
     55         if (stat(dir, &st) == 0) {
     56             if (!S_ISDIR(st.st_mode)) {
     57                 err = ALREADY_EXISTS;
     58                 goto done;
     59             }
     60         } else {
     61             if (mkdir(dir, 0770)) {
     62                 ALOGE("No incident reports today. "
     63                         "Unable to create incident report dir %s: %s", dir,
     64                         strerror(errno));
     65                 err = -errno;
     66                 goto done;
     67             }
     68             if (chmod(dir, 0770)) {
     69                 ALOGE("No incident reports today. "
     70                         "Unable to set permissions for incident report dir %s: %s", dir,
     71                         strerror(errno));
     72                 err = -errno;
     73                 goto done;
     74             }
     75             if (chown(dir, AID_SYSTEM, AID_SYSTEM)) {
     76                 ALOGE("No incident reports today. Unable to change ownership of dir %s: %s\n",
     77                         dir, strerror(errno));
     78                 err = -errno;
     79                 goto done;
     80             }
     81         }
     82         if (!last) {
     83             *d++ = '/';
     84         }
     85     }
     86 
     87     // Ensure that the final directory is owned by the system with 0770. If it isn't
     88     // we won't write into it.
     89     if (stat(directory, &st) != 0) {
     90         ALOGE("No incident reports today. Can't stat: %s", directory);
     91         err = -errno;
     92         goto done;
     93     }
     94     if ((st.st_mode & 0777) != 0770) {
     95         ALOGE("No incident reports today. Mode is %0o on report directory %s",
     96                 st.st_mode, directory);
     97         err = BAD_VALUE;
     98         goto done;
     99     }
    100     if (st.st_uid != AID_SYSTEM || st.st_gid != AID_SYSTEM) {
    101         ALOGE("No incident reports today. Owner is %d and group is %d on report directory %s",
    102                 st.st_uid, st.st_gid, directory);
    103         err = BAD_VALUE;
    104         goto done;
    105     }
    106 
    107 done:
    108     free(dir);
    109     return err;
    110 }
    111 
    112 static bool
    113 stat_mtime_cmp(const pair<String8,struct stat>& a, const pair<String8,struct stat>& b)
    114 {
    115     return a.second.st_mtime < b.second.st_mtime;
    116 }
    117 
    118 void
    119 clean_directory(const char* directory, off_t maxSize, size_t maxCount)
    120 {
    121     DIR* dir;
    122     struct dirent* entry;
    123     struct stat st;
    124 
    125     vector<pair<String8,struct stat>> files;
    126 
    127     if ((dir = opendir(directory)) == NULL) {
    128         ALOGE("Couldn't open incident directory: %s", directory);
    129         return;
    130     }
    131 
    132     String8 dirbase(String8(directory) + "/");
    133 
    134     off_t totalSize = 0;
    135     size_t totalCount = 0;
    136 
    137     // Enumerate, count and add up size
    138     while ((entry = readdir(dir)) != NULL) {
    139         if (entry->d_name[0] == '.') {
    140             continue;
    141         }
    142         String8 filename = dirbase + entry->d_name;
    143         if (stat(filename.string(), &st) != 0) {
    144             ALOGE("Unable to stat file %s", filename.string());
    145             continue;
    146         }
    147         if (!S_ISREG(st.st_mode)) {
    148             continue;
    149         }
    150         files.push_back(pair<String8,struct stat>(filename, st));
    151 
    152         totalSize += st.st_size;
    153         totalCount++;
    154     }
    155 
    156     closedir(dir);
    157 
    158     // Count or size is less than max, then we're done.
    159     if (totalSize < maxSize && totalCount < maxCount) {
    160         return;
    161     }
    162 
    163     // Oldest files first.
    164     sort(files.begin(), files.end(), stat_mtime_cmp);
    165 
    166     // Remove files until we're under our limits.
    167     for (vector<pair<String8,struct stat>>::iterator it = files.begin();
    168             it != files.end() && totalSize >= maxSize && totalCount >= maxCount; it++) {
    169         remove(it->first.string());
    170         totalSize -= it->second.st_size;
    171         totalCount--;
    172     }
    173 }
    174