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 <stdlib.h>
18#include <sys/mount.h>
19#include <sys/socket.h>
20#include <sys/stat.h>
21#include <sys/types.h>
22#include <sys/wait.h>
23#include <netinet/in.h>
24#include <arpa/inet.h>
25#include <dirent.h>
26#include <errno.h>
27#include <fcntl.h>
28#include <fs_mgr.h>
29#include <stdio.h>
30#include <string.h>
31#include <stdint.h>
32#include <inttypes.h>
33#include <ctype.h>
34
35#define LOG_TAG "VoldCmdListener"
36
37#include <android-base/logging.h>
38#include <android-base/stringprintf.h>
39#include <android-base/unique_fd.h>
40#include <cutils/fs.h>
41
42#include <sysutils/SocketClient.h>
43#include <private/android_filesystem_config.h>
44
45#include "CommandListener.h"
46#include "VolumeManager.h"
47#include "VolumeBase.h"
48#include "ResponseCode.h"
49#include "Process.h"
50#include "Loop.h"
51#include "Devmapper.h"
52#include "MoveTask.h"
53#include "TrimTask.h"
54
55#define DUMP_ARGS 0
56#define DEBUG_APPFUSE 0
57
58using android::base::unique_fd;
59
60CommandListener::CommandListener() :
61                 FrameworkListener("vold", true) {
62    registerCmd(new DumpCmd());
63    registerCmd(new VolumeCmd());
64    registerCmd(new AsecCmd());
65    registerCmd(new ObbCmd());
66    registerCmd(new StorageCmd());
67    registerCmd(new FstrimCmd());
68    registerCmd(new AppFuseCmd());
69}
70
71#if DUMP_ARGS
72void CommandListener::dumpArgs(int argc, char **argv, int argObscure) {
73    char buffer[4096];
74    char *p = buffer;
75
76    memset(buffer, 0, sizeof(buffer));
77    int i;
78    for (i = 0; i < argc; i++) {
79        unsigned int len = strlen(argv[i]) + 1; // Account for space
80        if (i == argObscure) {
81            len += 2; // Account for {}
82        }
83        if (((p - buffer) + len) < (sizeof(buffer)-1)) {
84            if (i == argObscure) {
85                *p++ = '{';
86                *p++ = '}';
87                *p++ = ' ';
88                continue;
89            }
90            strcpy(p, argv[i]);
91            p+= strlen(argv[i]);
92            if (i != (argc -1)) {
93                *p++ = ' ';
94            }
95        }
96    }
97    SLOGD("%s", buffer);
98}
99#else
100void CommandListener::dumpArgs(int /*argc*/, char ** /*argv*/, int /*argObscure*/) { }
101#endif
102
103int CommandListener::sendGenericOkFail(SocketClient *cli, int cond) {
104    if (!cond) {
105        return cli->sendMsg(ResponseCode::CommandOkay, "Command succeeded", false);
106    } else {
107        return cli->sendMsg(ResponseCode::OperationFailed, "Command failed", false);
108    }
109}
110
111CommandListener::DumpCmd::DumpCmd() :
112                 VoldCommand("dump") {
113}
114
115int CommandListener::DumpCmd::runCommand(SocketClient *cli,
116                                         int /*argc*/, char ** /*argv*/) {
117    cli->sendMsg(0, "Dumping loop status", false);
118    if (Loop::dumpState(cli)) {
119        cli->sendMsg(ResponseCode::CommandOkay, "Loop dump failed", true);
120    }
121    cli->sendMsg(0, "Dumping DM status", false);
122    if (Devmapper::dumpState(cli)) {
123        cli->sendMsg(ResponseCode::CommandOkay, "Devmapper dump failed", true);
124    }
125    cli->sendMsg(0, "Dumping mounted filesystems", false);
126    FILE *fp = fopen("/proc/mounts", "re");
127    if (fp) {
128        char line[1024];
129        while (fgets(line, sizeof(line), fp)) {
130            line[strlen(line)-1] = '\0';
131            cli->sendMsg(0, line, false);;
132        }
133        fclose(fp);
134    }
135
136    cli->sendMsg(ResponseCode::CommandOkay, "dump complete", false);
137    return 0;
138}
139
140CommandListener::VolumeCmd::VolumeCmd() :
141                 VoldCommand("volume") {
142}
143
144int CommandListener::VolumeCmd::runCommand(SocketClient *cli,
145                                           int argc, char **argv) {
146    dumpArgs(argc, argv, -1);
147
148    if (argc < 2) {
149        cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
150        return 0;
151    }
152
153    VolumeManager *vm = VolumeManager::Instance();
154    std::lock_guard<std::mutex> lock(vm->getLock());
155
156    // TODO: tease out methods not directly related to volumes
157
158    std::string cmd(argv[1]);
159    if (cmd == "reset") {
160        return sendGenericOkFail(cli, vm->reset());
161
162    } else if (cmd == "shutdown") {
163        return sendGenericOkFail(cli, vm->shutdown());
164
165    } else if (cmd == "debug") {
166        return sendGenericOkFail(cli, vm->setDebug(true));
167
168    } else if (cmd == "partition" && argc > 3) {
169        // partition [diskId] [public|private|mixed] [ratio]
170        std::string id(argv[2]);
171        auto disk = vm->findDisk(id);
172        if (disk == nullptr) {
173            return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown disk", false);
174        }
175
176        std::string type(argv[3]);
177        if (type == "public") {
178            return sendGenericOkFail(cli, disk->partitionPublic());
179        } else if (type == "private") {
180            return sendGenericOkFail(cli, disk->partitionPrivate());
181        } else if (type == "mixed") {
182            if (argc < 4) {
183                return cli->sendMsg(ResponseCode::CommandSyntaxError, nullptr, false);
184            }
185            int frac = atoi(argv[4]);
186            return sendGenericOkFail(cli, disk->partitionMixed(frac));
187        } else {
188            return cli->sendMsg(ResponseCode::CommandSyntaxError, nullptr, false);
189        }
190
191    } else if (cmd == "mkdirs" && argc > 2) {
192        // mkdirs [path]
193        return sendGenericOkFail(cli, vm->mkdirs(argv[2]));
194
195    } else if (cmd == "user_added" && argc > 3) {
196        // user_added [user] [serial]
197        return sendGenericOkFail(cli, vm->onUserAdded(atoi(argv[2]), atoi(argv[3])));
198
199    } else if (cmd == "user_removed" && argc > 2) {
200        // user_removed [user]
201        return sendGenericOkFail(cli, vm->onUserRemoved(atoi(argv[2])));
202
203    } else if (cmd == "user_started" && argc > 2) {
204        // user_started [user]
205        return sendGenericOkFail(cli, vm->onUserStarted(atoi(argv[2])));
206
207    } else if (cmd == "user_stopped" && argc > 2) {
208        // user_stopped [user]
209        return sendGenericOkFail(cli, vm->onUserStopped(atoi(argv[2])));
210
211    } else if (cmd == "mount" && argc > 2) {
212        // mount [volId] [flags] [user]
213        std::string id(argv[2]);
214        auto vol = vm->findVolume(id);
215        if (vol == nullptr) {
216            return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
217        }
218
219        int mountFlags = (argc > 3) ? atoi(argv[3]) : 0;
220        userid_t mountUserId = (argc > 4) ? atoi(argv[4]) : -1;
221
222        vol->setMountFlags(mountFlags);
223        vol->setMountUserId(mountUserId);
224
225        int res = vol->mount();
226        if (mountFlags & android::vold::VolumeBase::MountFlags::kPrimary) {
227            vm->setPrimary(vol);
228        }
229        return sendGenericOkFail(cli, res);
230
231    } else if (cmd == "unmount" && argc > 2) {
232        // unmount [volId]
233        std::string id(argv[2]);
234        auto vol = vm->findVolume(id);
235        if (vol == nullptr) {
236            return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
237        }
238
239        return sendGenericOkFail(cli, vol->unmount());
240
241    } else if (cmd == "format" && argc > 3) {
242        // format [volId] [fsType|auto]
243        std::string id(argv[2]);
244        std::string fsType(argv[3]);
245        auto vol = vm->findVolume(id);
246        if (vol == nullptr) {
247            return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
248        }
249
250        return sendGenericOkFail(cli, vol->format(fsType));
251
252    } else if (cmd == "move_storage" && argc > 3) {
253        // move_storage [fromVolId] [toVolId]
254        auto fromVol = vm->findVolume(std::string(argv[2]));
255        auto toVol = vm->findVolume(std::string(argv[3]));
256        if (fromVol == nullptr || toVol == nullptr) {
257            return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
258        }
259
260        (new android::vold::MoveTask(fromVol, toVol))->start();
261        return sendGenericOkFail(cli, 0);
262
263    } else if (cmd == "benchmark" && argc > 2) {
264        // benchmark [volId]
265        std::string id(argv[2]);
266        nsecs_t res = vm->benchmarkPrivate(id);
267        return cli->sendMsg(ResponseCode::CommandOkay,
268                android::base::StringPrintf("%" PRId64, res).c_str(), false);
269
270    } else if (cmd == "forget_partition" && argc > 2) {
271        // forget_partition [partGuid]
272        std::string partGuid(argv[2]);
273        return sendGenericOkFail(cli, vm->forgetPartition(partGuid));
274
275    } else if (cmd == "remount_uid" && argc > 3) {
276        // remount_uid [uid] [none|default|read|write]
277        uid_t uid = atoi(argv[2]);
278        std::string mode(argv[3]);
279        return sendGenericOkFail(cli, vm->remountUid(uid, mode));
280    }
281
282    return cli->sendMsg(ResponseCode::CommandSyntaxError, nullptr, false);
283}
284
285CommandListener::StorageCmd::StorageCmd() :
286                 VoldCommand("storage") {
287}
288
289int CommandListener::StorageCmd::runCommand(SocketClient *cli,
290                                                      int argc, char **argv) {
291    /* Guarantied to be initialized by vold's main() before the CommandListener is active */
292    extern struct fstab *fstab;
293
294    dumpArgs(argc, argv, -1);
295
296    if (argc < 2) {
297        cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
298        return 0;
299    }
300
301    if (!strcmp(argv[1], "mountall")) {
302        if (argc != 2) {
303            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: mountall", false);
304            return 0;
305        }
306        fs_mgr_mount_all(fstab, MOUNT_MODE_DEFAULT);
307        cli->sendMsg(ResponseCode::CommandOkay, "Mountall ran successfully", false);
308        return 0;
309    }
310    if (!strcmp(argv[1], "users")) {
311        DIR *dir;
312        struct dirent *de;
313
314        if (argc < 3) {
315            cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument: user <mountpoint>", false);
316            return 0;
317        }
318        if (!(dir = opendir("/proc"))) {
319            cli->sendMsg(ResponseCode::OperationFailed, "Failed to open /proc", true);
320            return 0;
321        }
322
323        while ((de = readdir(dir))) {
324            int pid = Process::getPid(de->d_name);
325
326            if (pid < 0) {
327                continue;
328            }
329
330            char processName[255];
331            Process::getProcessName(pid, processName, sizeof(processName));
332
333            if (Process::checkFileDescriptorSymLinks(pid, argv[2]) ||
334                Process::checkFileMaps(pid, argv[2]) ||
335                Process::checkSymLink(pid, argv[2], "cwd") ||
336                Process::checkSymLink(pid, argv[2], "root") ||
337                Process::checkSymLink(pid, argv[2], "exe")) {
338
339                char msg[1024];
340                snprintf(msg, sizeof(msg), "%d %s", pid, processName);
341                cli->sendMsg(ResponseCode::StorageUsersListResult, msg, false);
342            }
343        }
344        closedir(dir);
345        cli->sendMsg(ResponseCode::CommandOkay, "Storage user list complete", false);
346    } else {
347        cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown storage cmd", false);
348    }
349    return 0;
350}
351
352CommandListener::AsecCmd::AsecCmd() :
353                 VoldCommand("asec") {
354}
355
356void CommandListener::AsecCmd::listAsecsInDirectory(SocketClient *cli, const char *directory) {
357    DIR *d = opendir(directory);
358
359    if (!d) {
360        cli->sendMsg(ResponseCode::OperationFailed, "Failed to open asec dir", true);
361        return;
362    }
363
364    size_t dirent_len = offsetof(struct dirent, d_name) +
365            fpathconf(dirfd(d), _PC_NAME_MAX) + 1;
366
367    struct dirent *dent = (struct dirent *) malloc(dirent_len);
368    if (dent == NULL) {
369        cli->sendMsg(ResponseCode::OperationFailed, "Failed to allocate memory", true);
370        return;
371    }
372
373    struct dirent *result;
374
375    while (!readdir_r(d, dent, &result) && result != NULL) {
376        if (dent->d_name[0] == '.')
377            continue;
378        if (dent->d_type != DT_REG)
379            continue;
380        size_t name_len = strlen(dent->d_name);
381        if (name_len > 5 && name_len < 260 &&
382                !strcmp(&dent->d_name[name_len - 5], ".asec")) {
383            char id[255];
384            memset(id, 0, sizeof(id));
385            strlcpy(id, dent->d_name, name_len - 4);
386            cli->sendMsg(ResponseCode::AsecListResult, id, false);
387        }
388    }
389    closedir(d);
390
391    free(dent);
392}
393
394int CommandListener::AsecCmd::runCommand(SocketClient *cli,
395                                                      int argc, char **argv) {
396    if (argc < 2) {
397        cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
398        return 0;
399    }
400
401    VolumeManager *vm = VolumeManager::Instance();
402    int rc = 0;
403
404    if (!strcmp(argv[1], "list")) {
405        dumpArgs(argc, argv, -1);
406
407        listAsecsInDirectory(cli, VolumeManager::SEC_ASECDIR_EXT);
408        listAsecsInDirectory(cli, VolumeManager::SEC_ASECDIR_INT);
409    } else if (!strcmp(argv[1], "create")) {
410        dumpArgs(argc, argv, 5);
411        if (argc != 8) {
412            cli->sendMsg(ResponseCode::CommandSyntaxError,
413                    "Usage: asec create <container-id> <size_mb> <fstype> <key> <ownerUid> "
414                    "<isExternal>", false);
415            return 0;
416        }
417
418        unsigned long numSectors = (atoi(argv[3]) * (1024 * 1024)) / 512;
419        const bool isExternal = (atoi(argv[7]) == 1);
420        rc = vm->createAsec(argv[2], numSectors, argv[4], argv[5], atoi(argv[6]), isExternal);
421    } else if (!strcmp(argv[1], "resize")) {
422        dumpArgs(argc, argv, -1);
423        if (argc != 5) {
424            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec resize <container-id> <size_mb> <key>", false);
425            return 0;
426        }
427        unsigned long numSectors = (atoi(argv[3]) * (1024 * 1024)) / 512;
428        rc = vm->resizeAsec(argv[2], numSectors, argv[4]);
429    } else if (!strcmp(argv[1], "finalize")) {
430        dumpArgs(argc, argv, -1);
431        if (argc != 3) {
432            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec finalize <container-id>", false);
433            return 0;
434        }
435        rc = vm->finalizeAsec(argv[2]);
436    } else if (!strcmp(argv[1], "fixperms")) {
437        dumpArgs(argc, argv, -1);
438        if  (argc != 5) {
439            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec fixperms <container-id> <gid> <filename>", false);
440            return 0;
441        }
442
443        char *endptr;
444        gid_t gid = (gid_t) strtoul(argv[3], &endptr, 10);
445        if (*endptr != '\0') {
446            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec fixperms <container-id> <gid> <filename>", false);
447            return 0;
448        }
449
450        rc = vm->fixupAsecPermissions(argv[2], gid, argv[4]);
451    } else if (!strcmp(argv[1], "destroy")) {
452        dumpArgs(argc, argv, -1);
453        if (argc < 3) {
454            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec destroy <container-id> [force]", false);
455            return 0;
456        }
457        bool force = false;
458        if (argc > 3 && !strcmp(argv[3], "force")) {
459            force = true;
460        }
461        rc = vm->destroyAsec(argv[2], force);
462    } else if (!strcmp(argv[1], "mount")) {
463        dumpArgs(argc, argv, 3);
464        if (argc != 6) {
465            cli->sendMsg(ResponseCode::CommandSyntaxError,
466                    "Usage: asec mount <namespace-id> <key> <ownerUid> <ro|rw>", false);
467            return 0;
468        }
469        bool readOnly = true;
470        if (!strcmp(argv[5], "rw")) {
471            readOnly = false;
472        }
473        rc = vm->mountAsec(argv[2], argv[3], atoi(argv[4]), readOnly);
474    } else if (!strcmp(argv[1], "unmount")) {
475        dumpArgs(argc, argv, -1);
476        if (argc < 3) {
477            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec unmount <container-id> [force]", false);
478            return 0;
479        }
480        bool force = false;
481        if (argc > 3 && !strcmp(argv[3], "force")) {
482            force = true;
483        }
484        rc = vm->unmountAsec(argv[2], force);
485    } else if (!strcmp(argv[1], "rename")) {
486        dumpArgs(argc, argv, -1);
487        if (argc != 4) {
488            cli->sendMsg(ResponseCode::CommandSyntaxError,
489                    "Usage: asec rename <old_id> <new_id>", false);
490            return 0;
491        }
492        rc = vm->renameAsec(argv[2], argv[3]);
493    } else if (!strcmp(argv[1], "path")) {
494        dumpArgs(argc, argv, -1);
495        if (argc != 3) {
496            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec path <container-id>", false);
497            return 0;
498        }
499        char path[255];
500
501        if (!(rc = vm->getAsecMountPath(argv[2], path, sizeof(path)))) {
502            cli->sendMsg(ResponseCode::AsecPathResult, path, false);
503            return 0;
504        }
505    } else if (!strcmp(argv[1], "fspath")) {
506        dumpArgs(argc, argv, -1);
507        if (argc != 3) {
508            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec fspath <container-id>", false);
509            return 0;
510        }
511        char path[255];
512
513        if (!(rc = vm->getAsecFilesystemPath(argv[2], path, sizeof(path)))) {
514            cli->sendMsg(ResponseCode::AsecPathResult, path, false);
515            return 0;
516        }
517    } else {
518        dumpArgs(argc, argv, -1);
519        cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown asec cmd", false);
520    }
521
522    if (!rc) {
523        cli->sendMsg(ResponseCode::CommandOkay, "asec operation succeeded", false);
524    } else {
525        rc = ResponseCode::convertFromErrno();
526        cli->sendMsg(rc, "asec operation failed", true);
527    }
528
529    return 0;
530}
531
532CommandListener::ObbCmd::ObbCmd() :
533                 VoldCommand("obb") {
534}
535
536int CommandListener::ObbCmd::runCommand(SocketClient *cli,
537                                                      int argc, char **argv) {
538    if (argc < 2) {
539        cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
540        return 0;
541    }
542
543    VolumeManager *vm = VolumeManager::Instance();
544    int rc = 0;
545
546    if (!strcmp(argv[1], "list")) {
547        dumpArgs(argc, argv, -1);
548
549        rc = vm->listMountedObbs(cli);
550    } else if (!strcmp(argv[1], "mount")) {
551            dumpArgs(argc, argv, 3);
552            if (argc != 5) {
553                cli->sendMsg(ResponseCode::CommandSyntaxError,
554                        "Usage: obb mount <filename> <key> <ownerGid>", false);
555                return 0;
556            }
557            rc = vm->mountObb(argv[2], argv[3], atoi(argv[4]));
558    } else if (!strcmp(argv[1], "unmount")) {
559        dumpArgs(argc, argv, -1);
560        if (argc < 3) {
561            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: obb unmount <source file> [force]", false);
562            return 0;
563        }
564        bool force = false;
565        if (argc > 3 && !strcmp(argv[3], "force")) {
566            force = true;
567        }
568        rc = vm->unmountObb(argv[2], force);
569    } else if (!strcmp(argv[1], "path")) {
570        dumpArgs(argc, argv, -1);
571        if (argc != 3) {
572            cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: obb path <source file>", false);
573            return 0;
574        }
575        char path[255];
576
577        if (!(rc = vm->getObbMountPath(argv[2], path, sizeof(path)))) {
578            cli->sendMsg(ResponseCode::AsecPathResult, path, false);
579            return 0;
580        }
581    } else {
582        dumpArgs(argc, argv, -1);
583        cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown obb cmd", false);
584    }
585
586    if (!rc) {
587        cli->sendMsg(ResponseCode::CommandOkay, "obb operation succeeded", false);
588    } else {
589        rc = ResponseCode::convertFromErrno();
590        cli->sendMsg(rc, "obb operation failed", true);
591    }
592
593    return 0;
594}
595
596CommandListener::FstrimCmd::FstrimCmd() :
597                 VoldCommand("fstrim") {
598}
599int CommandListener::FstrimCmd::runCommand(SocketClient *cli,
600                                                      int argc, char **argv) {
601    if ((cli->getUid() != 0) && (cli->getUid() != AID_SYSTEM)) {
602        cli->sendMsg(ResponseCode::CommandNoPermission, "No permission to run fstrim commands", false);
603        return 0;
604    }
605
606    if (argc < 2) {
607        cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
608        return 0;
609    }
610
611    VolumeManager *vm = VolumeManager::Instance();
612    std::lock_guard<std::mutex> lock(vm->getLock());
613
614    int flags = 0;
615
616    std::string cmd(argv[1]);
617    if (cmd == "dotrim") {
618        flags = 0;
619    } else if (cmd == "dotrimbench") {
620        flags = android::vold::TrimTask::Flags::kBenchmarkAfter;
621    } else if (cmd == "dodtrim") {
622        flags = android::vold::TrimTask::Flags::kDeepTrim;
623    } else if (cmd == "dodtrimbench") {
624        flags = android::vold::TrimTask::Flags::kDeepTrim
625                | android::vold::TrimTask::Flags::kBenchmarkAfter;
626    }
627
628    (new android::vold::TrimTask(flags))->start();
629    return sendGenericOkFail(cli, 0);
630}
631
632static size_t kAppFuseMaxMountPointName = 32;
633
634static android::status_t getMountPath(uid_t uid, const std::string& name, std::string* path) {
635    if (name.size() > kAppFuseMaxMountPointName) {
636        LOG(ERROR) << "AppFuse mount name is too long.";
637        return -EINVAL;
638    }
639    for (size_t i = 0; i < name.size(); i++) {
640        if (!isalnum(name[i])) {
641            LOG(ERROR) << "AppFuse mount name contains invalid character.";
642            return -EINVAL;
643        }
644    }
645    *path = android::base::StringPrintf("/mnt/appfuse/%d_%s", uid, name.c_str());
646    return android::OK;
647}
648
649static android::status_t mountInNamespace(uid_t uid, int device_fd, const std::string& path) {
650    // Remove existing mount.
651    android::vold::ForceUnmount(path);
652
653    const auto opts = android::base::StringPrintf(
654            "fd=%i,"
655            "rootmode=40000,"
656            "default_permissions,"
657            "allow_other,"
658            "user_id=%d,group_id=%d,"
659            "context=\"u:object_r:app_fuse_file:s0\","
660            "fscontext=u:object_r:app_fusefs:s0",
661            device_fd,
662            uid,
663            uid);
664
665    const int result = TEMP_FAILURE_RETRY(mount(
666            "/dev/fuse", path.c_str(), "fuse",
667            MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_NOATIME, opts.c_str()));
668    if (result != 0) {
669        PLOG(ERROR) << "Failed to mount " << path;
670        return -errno;
671    }
672
673    return android::OK;
674}
675
676static android::status_t runCommandInNamespace(const std::string& command,
677                                               uid_t uid,
678                                               pid_t pid,
679                                               const std::string& path,
680                                               int device_fd) {
681    if (DEBUG_APPFUSE) {
682        LOG(DEBUG) << "Run app fuse command " << command << " for the path " << path
683                   << " in namespace " << uid;
684    }
685
686    unique_fd dir(open("/proc", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
687    if (dir.get() == -1) {
688        PLOG(ERROR) << "Failed to open /proc";
689        return -errno;
690    }
691
692    // Obtains process file descriptor.
693    const std::string pid_str = android::base::StringPrintf("%d", pid);
694    const unique_fd pid_fd(
695            openat(dir.get(), pid_str.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC));
696    if (pid_fd.get() == -1) {
697        PLOG(ERROR) << "Failed to open /proc/" << pid;
698        return -errno;
699    }
700
701    // Check UID of process.
702    {
703        struct stat sb;
704        const int result = fstat(pid_fd.get(), &sb);
705        if (result == -1) {
706            PLOG(ERROR) << "Failed to stat /proc/" << pid;
707            return -errno;
708        }
709        if (sb.st_uid != AID_SYSTEM) {
710            LOG(ERROR) << "Only system can mount appfuse. UID expected=" << AID_SYSTEM
711                    << ", actual=" << sb.st_uid;
712            return -EPERM;
713        }
714    }
715
716    // Matches so far, but refuse to touch if in root namespace
717    {
718        char rootName[PATH_MAX];
719        char pidName[PATH_MAX];
720        const int root_result =
721                android::vold::SaneReadLinkAt(dir.get(), "1/ns/mnt", rootName, PATH_MAX);
722        const int pid_result =
723                android::vold::SaneReadLinkAt(pid_fd.get(), "ns/mnt", pidName, PATH_MAX);
724        if (root_result == -1) {
725            LOG(ERROR) << "Failed to readlink for /proc/1/ns/mnt";
726            return -EPERM;
727        }
728        if (pid_result == -1) {
729            LOG(ERROR) << "Failed to readlink for /proc/" << pid << "/ns/mnt";
730            return -EPERM;
731        }
732        if (!strcmp(rootName, pidName)) {
733            LOG(ERROR) << "Don't mount appfuse in root namespace";
734            return -EPERM;
735        }
736    }
737
738    // We purposefully leave the namespace open across the fork
739    unique_fd ns_fd(openat(pid_fd.get(), "ns/mnt", O_RDONLY)); // not O_CLOEXEC
740    if (ns_fd.get() < 0) {
741        PLOG(ERROR) << "Failed to open namespace for /proc/" << pid << "/ns/mnt";
742        return -errno;
743    }
744
745    int child = fork();
746    if (child == 0) {
747        if (setns(ns_fd.get(), CLONE_NEWNS) != 0) {
748            PLOG(ERROR) << "Failed to setns";
749            _exit(-errno);
750        }
751
752        if (command == "mount") {
753            _exit(mountInNamespace(uid, device_fd, path));
754        } else if (command == "unmount") {
755            // If it's just after all FD opened on mount point are closed, umount2 can fail with
756            // EBUSY. To avoid the case, specify MNT_DETACH.
757            if (umount2(path.c_str(), UMOUNT_NOFOLLOW | MNT_DETACH) != 0 &&
758                    errno != EINVAL && errno != ENOENT) {
759                PLOG(ERROR) << "Failed to unmount directory.";
760                _exit(-errno);
761            }
762            if (rmdir(path.c_str()) != 0) {
763                PLOG(ERROR) << "Failed to remove the mount directory.";
764                _exit(-errno);
765            }
766            _exit(android::OK);
767        } else {
768            LOG(ERROR) << "Unknown appfuse command " << command;
769            _exit(-EPERM);
770        }
771    }
772
773    if (child == -1) {
774        PLOG(ERROR) << "Failed to folk child process";
775        return -errno;
776    }
777
778    android::status_t status;
779    TEMP_FAILURE_RETRY(waitpid(child, &status, 0));
780
781    return status;
782}
783
784CommandListener::AppFuseCmd::AppFuseCmd() : VoldCommand("appfuse") {}
785
786int CommandListener::AppFuseCmd::runCommand(SocketClient *cli, int argc, char **argv) {
787    if (argc < 2) {
788        cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing argument", false);
789        return 0;
790    }
791
792    const std::string command(argv[1]);
793
794    if (command == "mount" && argc == 5) {
795        const uid_t uid = atoi(argv[2]);
796        const pid_t pid = atoi(argv[3]);
797        const std::string name(argv[4]);
798
799        // Check mount point name.
800        std::string path;
801        if (getMountPath(uid, name, &path) != android::OK) {
802            return cli->sendMsg(ResponseCode::CommandParameterError,
803                                "Invalid mount point name.",
804                                false);
805        }
806
807        // Create directories.
808        {
809            const android::status_t result = android::vold::PrepareDir(path, 0700, 0, 0);
810            if (result != android::OK) {
811                PLOG(ERROR) << "Failed to prepare directory " << path;
812                return sendGenericOkFail(cli, result);
813            }
814        }
815
816        // Open device FD.
817        unique_fd device_fd(open("/dev/fuse", O_RDWR)); // not O_CLOEXEC
818        if (device_fd.get() == -1) {
819            PLOG(ERROR) << "Failed to open /dev/fuse";
820            return sendGenericOkFail(cli, -errno);
821        }
822
823        // Mount.
824        {
825            const android::status_t result =
826                    runCommandInNamespace(command, uid, pid, path, device_fd.get());
827            if (result != android::OK) {
828                return sendGenericOkFail(cli, result);
829            }
830        }
831
832        return sendFd(cli, device_fd.get());
833    } else if (command == "unmount" && argc == 5) {
834        const uid_t uid = atoi(argv[2]);
835        const uid_t pid = atoi(argv[3]);
836        const std::string name(argv[4]);
837
838        // Check mount point name.
839        std::string path;
840        if (getMountPath(uid, name, &path) != android::OK) {
841            return cli->sendMsg(ResponseCode::CommandParameterError,
842                                "Invalid mount point name.",
843                                false);
844        }
845
846        const android::status_t result =
847                runCommandInNamespace(command, uid, pid, path, -1 /* device_fd */);
848        return sendGenericOkFail(cli, result);
849    }
850
851    return cli->sendMsg(ResponseCode::CommandSyntaxError,  "Unknown appfuse cmd", false);
852}
853
854android::status_t CommandListener::AppFuseCmd::sendFd(SocketClient *cli, int fd) {
855    struct iovec data;
856    char dataBuffer[128];
857    char controlBuffer[CMSG_SPACE(sizeof(int))];
858    struct msghdr message;
859
860    // Message.
861    memset(&message, 0, sizeof(struct msghdr));
862    message.msg_iov = &data;
863    message.msg_iovlen = 1;
864    message.msg_control = controlBuffer;
865    message.msg_controllen = CMSG_SPACE(sizeof(int));
866
867    // Data.
868    data.iov_base = dataBuffer;
869    data.iov_len = snprintf(dataBuffer,
870                            sizeof(dataBuffer),
871                            "200 %d AppFuse command succeeded",
872                            cli->getCmdNum()) + 1;
873
874    // Control.
875    struct cmsghdr* const controlMessage = CMSG_FIRSTHDR(&message);
876    memset(controlBuffer, 0, CMSG_SPACE(sizeof(int)));
877    controlMessage->cmsg_level = SOL_SOCKET;
878    controlMessage->cmsg_type = SCM_RIGHTS;
879    controlMessage->cmsg_len = CMSG_LEN(sizeof(int));
880    *((int *) CMSG_DATA(controlMessage)) = fd;
881
882    const int result = TEMP_FAILURE_RETRY(sendmsg(cli->getSocket(), &message, 0));
883    if (result == -1) {
884        PLOG(ERROR) << "Failed to send FD from vold";
885        return -errno;
886    }
887
888    return android::OK;
889}
890