recovery: Implement a volume manager

This is a copy of the pre-binderized vold which has been converted to
use direct calls instead of sockets and stripped down to only what is
needed to support recovery.

Includes:
  * Replace security_context_t type

    security_context_t has been marked as deprecated in libselinux from
    version 3.2. Update to the `char*` type.

    Bug: 190808996
    Test: m
    Change-Id: I6f40e161251c79893d41e12c368715736578aacc

  * recovery: volmgr: remove unused IsSupported

    Change-Id: If8206658fdfb6108221806c09c99bf0a30f4a586
    Signed-off-by: Jesse Chan <jc@lineageos.org>

  * recovery: volmgr: remove filesystem checks

    Those checks are not strictly necessary and we are
    not building fsck tools for recovery for now.

    Remove those checks so volmgr can be useful.

    Change-Id: I87756c61b933b6cdccd281c6276b686fbd36019f
    Signed-off-by: Jesse Chan <jc@lineageos.org>

  * recovery: fixup `EmulatedVolume creating`

    Avoid dangling pointer. Instead of pointing to FstabEntry create copy.

    Change-Id: I57f76006db09a6add2c173f43175f0f6b848d87b

  * recovery: fix volmgr cleaning up

    Don't reset pointer to netlink manager
    Delete disks in stop() rather then in ~VolumeManager
    Call destroy() before deleting disks cause delete expects the
      disk to be destroyed
    Clear the lists or we would read garbage data on the next scan

    Change-Id: Idadfa1f33b7cb5f2f3c780848a99344a6608420e

  * recovery: handle interrupts in apply update menu

    Change-Id: I1f78f9196634353b77986545332d7d52a5f0c161

Change-Id: Ic82d929e052b5ba70ecf7b475e0a223d77d9687e
diff --git a/volume_manager/Utils.cpp b/volume_manager/Utils.cpp
new file mode 100644
index 0000000..b8cf4eb
--- /dev/null
+++ b/volume_manager/Utils.cpp
@@ -0,0 +1,338 @@
+/*
+ * Copyright (C) 2015 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 "Utils.h"
+#include <volume_manager/VolumeManager.h>
+#include "Process.h"
+#include "sehandle.h"
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+
+#include <cutils/fs.h>
+#include <private/android_filesystem_config.h>
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <mutex>
+#include <thread>
+
+#ifndef UMOUNT_NOFOLLOW
+#define UMOUNT_NOFOLLOW 0x00000008 /* Don't follow symlink on umount */
+#endif
+
+using android::base::ReadFileToString;
+using android::base::StringPrintf;
+
+using namespace std::chrono_literals;
+
+namespace android {
+namespace volmgr {
+
+char* sBlkidContext = nullptr;
+char* sBlkidUntrustedContext = nullptr;
+char* sFsckContext = nullptr;
+char* sFsckUntrustedContext = nullptr;
+
+#include <blkid/blkid.h>
+
+static const char* kProcFilesystems = "/proc/filesystems";
+
+status_t CreateDeviceNode(const std::string& path, dev_t dev) {
+    const char* cpath = path.c_str();
+    status_t res = 0;
+
+    char* secontext = nullptr;
+    if (sehandle) {
+        if (!selabel_lookup(sehandle, &secontext, cpath, S_IFBLK)) {
+            setfscreatecon(secontext);
+        }
+    }
+
+    mode_t mode = 0660 | S_IFBLK;
+    if (mknod(cpath, mode, dev) < 0) {
+        if (errno != EEXIST) {
+            PLOG(ERROR) << "Failed to create device node for " << major(dev) << ":" << minor(dev)
+                        << " at " << path;
+            res = -errno;
+        }
+    }
+
+    if (secontext) {
+        setfscreatecon(nullptr);
+        freecon(secontext);
+    }
+
+    return res;
+}
+
+status_t DestroyDeviceNode(const std::string& path) {
+    const char* cpath = path.c_str();
+    if (TEMP_FAILURE_RETRY(unlink(cpath))) {
+        return -errno;
+    } else {
+        return OK;
+    }
+}
+
+status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
+    const char* cpath = path.c_str();
+
+    char* secontext = nullptr;
+    if (sehandle) {
+        if (!selabel_lookup(sehandle, &secontext, cpath, S_IFDIR)) {
+            setfscreatecon(secontext);
+        }
+    }
+
+    int res = fs_prepare_dir(cpath, mode, uid, gid);
+
+    if (secontext) {
+        setfscreatecon(nullptr);
+        freecon(secontext);
+    }
+
+    if (res == 0) {
+        return OK;
+    } else {
+        return -errno;
+    }
+}
+
+status_t ForceUnmount(const std::string& path, bool detach /* = false */) {
+    const char* cpath = path.c_str();
+    if (detach) {
+        if (!umount2(path.c_str(), UMOUNT_NOFOLLOW | MNT_DETACH) || errno == EINVAL ||
+            errno == ENOENT) {
+            return OK;
+        }
+        PLOG(WARNING) << "Failed to unmount " << path;
+        return -errno;
+    }
+    if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+        return OK;
+    }
+    sleep(1);
+
+    Process::killProcessesWithOpenFiles(cpath, SIGINT);
+    sleep(1);
+    if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+        return OK;
+    }
+
+    Process::killProcessesWithOpenFiles(cpath, SIGTERM);
+    sleep(1);
+    if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+        return OK;
+    }
+
+    Process::killProcessesWithOpenFiles(cpath, SIGKILL);
+    sleep(1);
+    if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+        return OK;
+    }
+
+    return -errno;
+}
+
+status_t KillProcessesUsingPath(const std::string& path) {
+    const char* cpath = path.c_str();
+    if (Process::killProcessesWithOpenFiles(cpath, SIGINT) == 0) {
+        return OK;
+    }
+    sleep(1);
+
+    if (Process::killProcessesWithOpenFiles(cpath, SIGTERM) == 0) {
+        return OK;
+    }
+    sleep(1);
+
+    if (Process::killProcessesWithOpenFiles(cpath, SIGKILL) == 0) {
+        return OK;
+    }
+    sleep(1);
+
+    // Send SIGKILL a second time to determine if we've
+    // actually killed everyone with open files
+    if (Process::killProcessesWithOpenFiles(cpath, SIGKILL) == 0) {
+        return OK;
+    }
+    PLOG(ERROR) << "Failed to kill processes using " << path;
+    return -EBUSY;
+}
+
+status_t BindMount(const std::string& source, const std::string& target) {
+    if (::mount(source.c_str(), target.c_str(), "", MS_BIND, NULL)) {
+        PLOG(ERROR) << "Failed to bind mount " << source << " to " << target;
+        return -errno;
+    }
+    return OK;
+}
+
+static status_t readMetadata(const std::string& path, std::string& fsType, std::string& fsUuid,
+                             std::string& fsLabel) {
+    char* val = NULL;
+    val = blkid_get_tag_value(NULL, "TYPE", path.c_str());
+    if (val) {
+        fsType = val;
+    }
+    val = blkid_get_tag_value(NULL, "UUID", path.c_str());
+    if (val) {
+        fsUuid = val;
+    }
+    val = blkid_get_tag_value(NULL, "LABEL", path.c_str());
+    if (val) {
+        fsLabel = val;
+    }
+
+    return OK;
+}
+
+status_t ReadMetadata(const std::string& path, std::string& fsType, std::string& fsUuid,
+                      std::string& fsLabel) {
+    return readMetadata(path, fsType, fsUuid, fsLabel);
+}
+
+status_t ReadMetadataUntrusted(const std::string& path, std::string& fsType, std::string& fsUuid,
+                               std::string& fsLabel) {
+    return readMetadata(path, fsType, fsUuid, fsLabel);
+}
+
+status_t ForkExecvp(const std::vector<std::string>& args) {
+    return ForkExecvp(args, nullptr);
+}
+
+status_t ForkExecvp(const std::vector<std::string>& args, char* context) {
+    std::vector<std::string> output;
+    size_t argc = args.size();
+    char** argv = (char**)calloc(argc + 1, sizeof(char*));
+    for (size_t i = 0; i < argc; i++) {
+        argv[i] = (char*)args[i].c_str();
+        if (i == 0) {
+            LOG(VERBOSE) << args[i];
+        } else {
+            LOG(VERBOSE) << "    " << args[i];
+        }
+    }
+
+    if (setexeccon(context)) {
+        LOG(ERROR) << "Failed to setexeccon";
+        abort();
+    }
+
+    pid_t pid = fork();
+    int fork_errno = errno;
+    if (pid == 0) {
+        close(STDIN_FILENO);
+        close(STDOUT_FILENO);
+        close(STDERR_FILENO);
+
+        if (execvp(argv[0], argv)) {
+            PLOG(ERROR) << "Failed to exec";
+        }
+
+        _exit(1);
+    }
+
+    if (setexeccon(nullptr)) {
+        LOG(ERROR) << "Failed to setexeccon";
+        abort();
+    }
+
+    if (pid == -1) {
+        PLOG(ERROR) << "Failed to exec";
+        return -fork_errno;
+    }
+
+    waitpid(pid, nullptr, 0);
+
+    free(argv);
+    return OK;
+}
+
+bool IsFilesystemSupported(const std::string& fsType) {
+    std::string supported;
+    if (!ReadFileToString(kProcFilesystems, &supported)) {
+        PLOG(ERROR) << "Failed to read supported filesystems";
+        return false;
+    }
+
+    /* fuse filesystems */
+    supported.append("fuse\tntfs\n");
+
+    return supported.find(fsType + "\n") != std::string::npos;
+}
+
+status_t WipeBlockDevice(const std::string& path) {
+    status_t res = -1;
+    const char* c_path = path.c_str();
+    unsigned long nr_sec = 0;
+    unsigned long long range[2];
+
+    int fd = TEMP_FAILURE_RETRY(open(c_path, O_RDWR | O_CLOEXEC));
+    if (fd == -1) {
+        PLOG(ERROR) << "Failed to open " << path;
+        goto done;
+    }
+
+    if ((ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) {
+        PLOG(ERROR) << "Failed to determine size of " << path;
+        goto done;
+    }
+
+    range[0] = 0;
+    range[1] = (unsigned long long)nr_sec * 512;
+
+    LOG(INFO) << "About to discard " << range[1] << " on " << path;
+    if (ioctl(fd, BLKDISCARD, &range) == 0) {
+        LOG(INFO) << "Discard success on " << path;
+        res = 0;
+    } else {
+        PLOG(ERROR) << "Discard failure on " << path;
+    }
+
+done:
+    close(fd);
+    return res;
+}
+
+dev_t GetDevice(const std::string& path) {
+    struct stat sb;
+    if (stat(path.c_str(), &sb)) {
+        PLOG(WARNING) << "Failed to stat " << path;
+        return 0;
+    } else {
+        return sb.st_dev;
+    }
+}
+
+bool IsRunningInEmulator() {
+    return android::base::GetBoolProperty("ro.kernel.qemu", false);
+}
+
+}  // namespace volmgr
+}  // namespace android