1 files changed, 210 insertions, 0 deletions
diff --git a/volume_manager/Process.cpp b/volume_manager/Process.cpp
new file mode 100644
index 00000000..387d8d31
--- /dev/null
+++ b/volume_manager/Process.cpp
@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * Copyright (C) 2019 The LineageOS 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.
+ */
+
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define LOG_TAG "ProcessKiller"
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <cutils/log.h>
+
+#include "Process.h"
+
+using android::base::ReadFileToString;
+using android::base::StringPrintf;
+
+int Process::readSymLink(const char* path, char* link, size_t max) {
+    struct stat s;
+    int length;
+
+    if (lstat(path, &s) < 0) return 0;
+    if ((s.st_mode & S_IFMT) != S_IFLNK) return 0;
+
+    // we have a symlink
+    length = readlink(path, link, max - 1);
+    if (length <= 0) return 0;
+    link[length] = 0;
+    return 1;
+}
+
+int Process::pathMatchesMountPoint(const char* path, const char* mountPoint) {
+    int length = strlen(mountPoint);
+    if (length > 1 && strncmp(path, mountPoint, length) == 0) {
+        // we need to do extra checking if mountPoint does not end in a '/'
+        if (mountPoint[length - 1] == '/') return 1;
+        // if mountPoint does not have a trailing slash, we need to make sure
+        // there is one in the path to avoid partial matches.
+        return (path[length] == 0 || path[length] == '/');
+    }
+
+    return 0;
+}
+
+void Process::getProcessName(int pid, std::string& out_name) {
+    if (!ReadFileToString(StringPrintf("/proc/%d/cmdline", pid), &out_name)) {
+        out_name = "???";
+    }
+}
+
+int Process::checkFileDescriptorSymLinks(int pid, const char* mountPoint) {
+    return checkFileDescriptorSymLinks(pid, mountPoint, NULL, 0);
+}
+
+int Process::checkFileDescriptorSymLinks(int pid, const char* mountPoint, char* openFilename,
+                                         size_t max) {
+    // compute path to process's directory of open files
+    char path[PATH_MAX];
+    snprintf(path, sizeof(path), "/proc/%d/fd", pid);
+    DIR* dir = opendir(path);
+    if (!dir) return 0;
+
+    // remember length of the path
+    int parent_length = strlen(path);
+    // append a trailing '/'
+    path[parent_length++] = '/';
+
+    struct dirent* de;
+    while ((de = readdir(dir))) {
+        if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..") ||
+            strlen(de->d_name) + parent_length + 1 >= PATH_MAX)
+            continue;
+
+        // append the file name, after truncating to parent directory
+        path[parent_length] = 0;
+        strlcat(path, de->d_name, PATH_MAX);
+
+        char link[PATH_MAX];
+
+        if (readSymLink(path, link, sizeof(link)) && pathMatchesMountPoint(link, mountPoint)) {
+            if (openFilename) {
+                memset(openFilename, 0, max);
+                strlcpy(openFilename, link, max);
+            }
+            closedir(dir);
+            return 1;
+        }
+    }
+
+    closedir(dir);
+    return 0;
+}
+
+int Process::checkFileMaps(int pid, const char* mountPoint) {
+    return checkFileMaps(pid, mountPoint, NULL, 0);
+}
+
+int Process::checkFileMaps(int pid, const char* mountPoint, char* openFilename, size_t max) {
+    FILE* file;
+    char buffer[PATH_MAX + 100];
+
+    snprintf(buffer, sizeof(buffer), "/proc/%d/maps", pid);
+    file = fopen(buffer, "re");
+    if (!file) return 0;
+
+    while (fgets(buffer, sizeof(buffer), file)) {
+        // skip to the path
+        const char* path = strchr(buffer, '/');
+        if (path && pathMatchesMountPoint(path, mountPoint)) {
+            if (openFilename) {
+                memset(openFilename, 0, max);
+                strlcpy(openFilename, path, max);
+            }
+            fclose(file);
+            return 1;
+        }
+    }
+
+    fclose(file);
+    return 0;
+}
+
+int Process::checkSymLink(int pid, const char* mountPoint, const char* name) {
+    char path[PATH_MAX];
+    char link[PATH_MAX];
+
+    snprintf(path, sizeof(path), "/proc/%d/%s", pid, name);
+    if (readSymLink(path, link, sizeof(link)) && pathMatchesMountPoint(link, mountPoint)) return 1;
+    return 0;
+}
+
+int Process::getPid(const char* s) {
+    int result = 0;
+    while (*s) {
+        if (!isdigit(*s)) return -1;
+        result = 10 * result + (*s++ - '0');
+    }
+    return result;
+}
+
+/*
+ * Hunt down processes that have files open at the given mount point.
+ */
+int Process::killProcessesWithOpenFiles(const char* path, int signal) {
+    int count = 0;
+    DIR* dir;
+    struct dirent* de;
+
+    if (!(dir = opendir("/proc"))) {
+        SLOGE("opendir failed (%s)", strerror(errno));
+        return count;
+    }
+
+    while ((de = readdir(dir))) {
+        int pid = getPid(de->d_name);
+        if (pid == -1) continue;
+
+        std::string name;
+        getProcessName(pid, name);
+
+        char openfile[PATH_MAX];
+
+        if (checkFileDescriptorSymLinks(pid, path, openfile, sizeof(openfile))) {
+            SLOGE("Process %s (%d) has open file %s", name.c_str(), pid, openfile);
+        } else if (checkFileMaps(pid, path, openfile, sizeof(openfile))) {
+            SLOGE("Process %s (%d) has open filemap for %s", name.c_str(), pid, openfile);
+        } else if (checkSymLink(pid, path, "cwd")) {
+            SLOGE("Process %s (%d) has cwd within %s", name.c_str(), pid, path);
+        } else if (checkSymLink(pid, path, "root")) {
+            SLOGE("Process %s (%d) has chroot within %s", name.c_str(), pid, path);
+        } else if (checkSymLink(pid, path, "exe")) {
+            SLOGE("Process %s (%d) has executable path within %s", name.c_str(), pid, path);
+        } else {
+            continue;
+        }
+
+        if (signal != 0) {
+            SLOGW("Sending %s to process %d", strsignal(signal), pid);
+            kill(pid, signal);
+            count++;
+        }
+    }
+    closedir(dir);
+    return count;
+}