am eddf9bd6: Request specific tags from blkid.
* commit 'eddf9bd63c1f7e0f9709f7c58a1035fa43338325':
Request specific tags from blkid.
diff --git a/Android.mk b/Android.mk
index 38da8c7..1d36312 100644
--- a/Android.mk
+++ b/Android.mk
@@ -114,3 +114,15 @@
LOCAL_CONLYFLAGS := $(vold_conlyflags)
include $(BUILD_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
+LOCAL_CLANG := true
+LOCAL_SRC_FILES:= secdiscard.cpp
+LOCAL_MODULE:= secdiscard
+LOCAL_SHARED_LIBRARIES := libcutils
+LOCAL_CFLAGS := $(vold_cflags)
+LOCAL_CONLYFLAGS := $(vold_conlyflags)
+
+include $(BUILD_EXECUTABLE)
diff --git a/CryptCommandListener.cpp b/CryptCommandListener.cpp
index 2e46919..173be63 100644
--- a/CryptCommandListener.cpp
+++ b/CryptCommandListener.cpp
@@ -42,6 +42,7 @@
#include "Process.h"
#include "ResponseCode.h"
#include "cryptfs.h"
+#include "Ext4Crypt.h"
#define DUMP_ARGS 0
@@ -288,6 +289,35 @@
dumpArgs(argc, argv, -1);
cryptfs_clear_password();
rc = 0;
+ } else if (!strcmp(argv[1], "setusercryptopolicies")) {
+ if (argc != 3) {
+ cli->sendMsg(ResponseCode::CommandSyntaxError,
+ "Usage: cryptfs setusercryptopolicies <path>", false);
+ return 0;
+ }
+ SLOGD("cryptfs setusercryptopolicies");
+ dumpArgs(argc, argv, -1);
+ rc = e4crypt_set_user_crypto_policies(argv[2]);
+ } else if (!strcmp(argv[1], "createnewuserdir")) {
+ if (argc != 4) {
+ cli->sendMsg(ResponseCode::CommandSyntaxError,
+ "Usage: cryptfs createnewuserdir <userHandle> <path>", false);
+ return 0;
+ }
+ // ext4enc:TODO: send a CommandSyntaxError if argv[2] not an integer
+ SLOGD("cryptfs createnewuserdir");
+ dumpArgs(argc, argv, -1);
+ rc = e4crypt_create_new_user_dir(argv[2], argv[3]);
+ } else if (!strcmp(argv[1], "deleteuserkey")) {
+ if (argc != 3) {
+ cli->sendMsg(ResponseCode::CommandSyntaxError,
+ "Usage: cryptfs deleteuserkey <userHandle>", false);
+ return 0;
+ }
+ // ext4enc:TODO: send a CommandSyntaxError if argv[2] not an integer
+ SLOGD("cryptfs deleteuserkey");
+ dumpArgs(argc, argv, -1);
+ rc = e4crypt_delete_user_key(argv[2]);
} else {
dumpArgs(argc, argv, -1);
cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown cryptfs cmd", false);
diff --git a/Ext4Crypt.cpp b/Ext4Crypt.cpp
index d200ca6..95cbfb7 100644
--- a/Ext4Crypt.cpp
+++ b/Ext4Crypt.cpp
@@ -7,17 +7,24 @@
#include <sstream>
#include <errno.h>
+#include <dirent.h>
#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
#include <cutils/properties.h>
#include <openssl/sha.h>
#include "unencrypted_properties.h"
#include "key_control.h"
#include "cryptfs.h"
+#include "ext4_crypt_init_extensions.h"
#define LOG_TAG "Ext4Crypt"
#include "cutils/log.h"
#include <cutils/klog.h>
+#include <base/file.h>
+#include <base/stringprintf.h>
namespace {
// Key length in bits
@@ -69,6 +76,8 @@
}
}
+static std::string e4crypt_install_key(const std::string &key);
+
static int put_crypt_ftr_and_key(const crypt_mnt_ftr& crypt_ftr,
UnencryptedProperties& props)
{
@@ -240,10 +249,10 @@
return -1;
}
- const unsigned char* master_key
+ const unsigned char* master_key_bytes
= reinterpret_cast<const unsigned char*>(&mki->second.master_key[0]);
- if (cryptfs_set_password(&ftr, password, master_key)) {
+ if (cryptfs_set_password(&ftr, password, master_key_bytes)) {
SLOGE("Failed to set password");
return -1;
}
@@ -276,6 +285,7 @@
return 0;
}
+// Get raw keyref - used to make keyname and to pass to ioctl
static std::string generate_key_ref(const char* key, int length)
{
SHA512_CTX c;
@@ -305,8 +315,8 @@
return -1;
}
- unsigned char master_key[key_length / 8];
- if (cryptfs_get_master_key (&ftr, password, master_key)){
+ unsigned char master_key_bytes[key_length / 8];
+ if (cryptfs_get_master_key (&ftr, password, master_key_bytes)){
SLOGI("Incorrect password");
ftr.failed_decrypt_count++;
if (put_crypt_ftr_and_key(ftr, key_props)) {
@@ -321,15 +331,29 @@
SLOGW("Failed to reset failed_decrypt_count");
}
}
+ std::string master_key(reinterpret_cast<char*>(master_key_bytes),
+ sizeof(master_key_bytes));
struct timespec now;
clock_gettime(CLOCK_BOOTTIME, &now);
- s_key_store[path] = keys{std::string(reinterpret_cast<char*>(master_key),
- sizeof(master_key)),
- password,
+ s_key_store[path] = keys{master_key, password,
now.tv_sec + password_max_age_seconds};
+ auto raw_ref = e4crypt_install_key(master_key);
+ if (raw_ref.empty()) {
+ return -1;
+ }
- // Install password into global keyring
+ // Save reference to key so we can set policy later
+ if (!props.Set(properties::ref, raw_ref)) {
+ SLOGE("Cannot save key reference");
+ return -1;
+ }
+
+ return 0;
+}
+
+static ext4_encryption_key fill_key(const std::string &key)
+{
// ext4enc:TODO Currently raw key is required to be of length
// sizeof(ext4_key.raw) == EXT4_MAX_KEY_SIZE, so zero pad to
// this length. Change when kernel bug is fixed.
@@ -339,47 +363,56 @@
memset(ext4_key.raw, 0, sizeof(ext4_key.raw));
static_assert(key_length / 8 <= sizeof(ext4_key.raw),
"Key too long!");
- memcpy(ext4_key.raw, master_key, key_length / 8);
+ memcpy(ext4_key.raw, &key[0], key.size());
+ return ext4_key;
+}
- // Get raw keyref - used to make keyname and to pass to ioctl
- auto raw_ref = generate_key_ref(ext4_key.raw, ext4_key.size);
-
- // Generate keyname
+static std::string keyname(const std::string &raw_ref)
+{
std::ostringstream o;
+ o << "ext4:";
for (auto i = raw_ref.begin(); i != raw_ref.end(); ++i) {
o << std::hex << std::setw(2) << std::setfill('0') << (int)*i;
}
- auto ref = std::string("ext4:") + o.str();
+ return o.str();
+}
- // Find existing keyring
- key_serial_t device_keyring = keyctl_search(KEY_SPEC_SESSION_KEYRING,
- "keyring", "e4crypt", 0);
+// Get the keyring we store all keys in
+static key_serial_t e4crypt_keyring()
+{
+ return keyctl_search(KEY_SPEC_SESSION_KEYRING, "keyring", "e4crypt", 0);
+}
+static int e4crypt_install_key(const ext4_encryption_key &ext4_key, const std::string &ref)
+{
+ key_serial_t device_keyring = e4crypt_keyring();
SLOGI("Found device_keyring - id is %d", device_keyring);
-
- // Add key ...
key_serial_t key_id = add_key("logon", ref.c_str(),
(void*)&ext4_key, sizeof(ext4_key),
device_keyring);
-
if (key_id == -1) {
SLOGE("Failed to insert key into keyring with error %s",
strerror(errno));
return -1;
}
-
SLOGI("Added key %d (%s) to keyring %d in process %d",
key_id, ref.c_str(), device_keyring, getpid());
-
- // Save reference to key so we can set policy later
- if (!props.Set(properties::ref, raw_ref)) {
- SLOGE("Cannot save key reference");
- return -1;
- }
-
return 0;
}
+// Install password into global keyring
+// Return raw key reference for use in policy
+static std::string e4crypt_install_key(const std::string &key)
+{
+ auto ext4_key = fill_key(key);
+ auto raw_ref = generate_key_ref(ext4_key.raw, ext4_key.size);
+ auto ref = keyname(raw_ref);
+ if (e4crypt_install_key(ext4_key, ref) == -1) {
+ return "";
+ }
+ return raw_ref;
+}
+
int e4crypt_restart(const char* path)
{
SLOGI("e4crypt_restart");
@@ -473,3 +506,161 @@
return GetPropsOrAltProps(path).GetChild(properties::props)
.Set(fieldname, std::string(value)) ? 0 : -1;
}
+
+static std::string get_key_path(
+ const char *mount_path,
+ const char *user_handle)
+{
+ // ext4enc:TODO get the path properly
+ auto key_dir = android::base::StringPrintf("%s/misc/vold/user_keys",
+ mount_path);
+ if (mkdir(key_dir.c_str(), 0700) < 0 && errno != EEXIST) {
+ SLOGE("Unable to create %s (%s)", key_dir.c_str(), strerror(errno));
+ return "";
+ }
+ return key_dir + "/" + user_handle;
+}
+
+// ext4enc:TODO this can't be the only place keys are read from /dev/urandom
+// we should unite those places.
+static std::string e4crypt_get_key(
+ const std::string &key_path,
+ bool create_if_absent)
+{
+ std::string content;
+ if (android::base::ReadFileToString(key_path, &content)) {
+ if (content.size() != key_length/8) {
+ SLOGE("Wrong size key %zu in %s", content.size(), key_path.c_str());
+ return "";
+ }
+ return content;
+ }
+ if (!create_if_absent) {
+ SLOGE("No key found in %s", key_path.c_str());
+ return "";
+ }
+ std::ifstream urandom("/dev/urandom");
+ if (!urandom) {
+ SLOGE("Unable to open /dev/urandom (%s)", strerror(errno));
+ return "";
+ }
+ char key_bytes[key_length / 8];
+ errno = 0;
+ urandom.read(key_bytes, sizeof(key_bytes));
+ if (!urandom) {
+ SLOGE("Unable to read key from /dev/urandom (%s)", strerror(errno));
+ return "";
+ }
+ std::string key(key_bytes, sizeof(key_bytes));
+ if (!android::base::WriteStringToFile(key, key_path)) {
+ SLOGE("Unable to write key to %s (%s)",
+ key_path.c_str(), strerror(errno));
+ return "";
+ }
+ return key;
+}
+
+static int e4crypt_set_user_policy(const char *mount_path, const char *user_handle,
+ const char *path, bool create_if_absent)
+{
+ SLOGD("e4crypt_set_user_policy for %s", user_handle);
+ auto user_key = e4crypt_get_key(
+ get_key_path(mount_path, user_handle),
+ create_if_absent);
+ if (user_key.empty()) {
+ return -1;
+ }
+ auto raw_ref = e4crypt_install_key(user_key);
+ if (raw_ref.empty()) {
+ return -1;
+ }
+ return do_policy_set(path, raw_ref.c_str(), raw_ref.size());
+}
+
+int e4crypt_create_new_user_dir(const char *user_handle, const char *path) {
+ SLOGD("e4crypt_create_new_user_dir(\"%s\", \"%s\")", user_handle, path);
+ if (mkdir(path, S_IRWXU | S_IRWXG | S_IXOTH) < 0) {
+ return -1;
+ }
+ if (chmod(path, S_IRWXU | S_IRWXG | S_IXOTH) < 0) {
+ return -1;
+ }
+ if (e4crypt_crypto_complete(DATA_MNT_POINT) == 0) {
+ // ext4enc:TODO handle errors from this.
+ e4crypt_set_user_policy(DATA_MNT_POINT, user_handle, path, true);
+ }
+ return 0;
+}
+
+static bool is_numeric(const char *name) {
+ for (const char *p = name; *p != '\0'; p++) {
+ if (!isdigit(*p))
+ return false;
+ }
+ return true;
+}
+
+int e4crypt_set_user_crypto_policies(const char *dir)
+{
+ if (e4crypt_crypto_complete(DATA_MNT_POINT) != 0) {
+ return 0;
+ }
+ SLOGD("e4crypt_set_user_crypto_policies");
+ std::unique_ptr<DIR, int(*)(DIR*)> dirp(opendir(dir), closedir);
+ if (!dirp) {
+ SLOGE("Unable to read directory %s, error %s\n",
+ dir, strerror(errno));
+ return -1;
+ }
+ for (;;) {
+ struct dirent *result = readdir(dirp.get());
+ if (!result) {
+ // ext4enc:TODO check errno
+ break;
+ }
+ if (result->d_type != DT_DIR || !is_numeric(result->d_name)) {
+ continue; // skips user 0, which is a symlink
+ }
+ auto user_dir = std::string() + dir + "/" + result->d_name;
+ // ext4enc:TODO don't hardcode /data
+ if (e4crypt_set_user_policy("/data", result->d_name,
+ user_dir.c_str(), false)) {
+ // ext4enc:TODO If this function fails, stop the boot: we must
+ // deliver on promised encryption.
+ SLOGE("Unable to set policy on %s\n", user_dir.c_str());
+ }
+ }
+ return 0;
+}
+
+int e4crypt_delete_user_key(const char *user_handle) {
+ SLOGD("e4crypt_delete_user_key(\"%s\")", user_handle);
+ auto key_path = get_key_path(DATA_MNT_POINT, user_handle);
+ auto key = e4crypt_get_key(key_path, false);
+ auto ext4_key = fill_key(key);
+ auto ref = keyname(generate_key_ref(ext4_key.raw, ext4_key.size));
+ auto key_serial = keyctl_search(e4crypt_keyring(), "logon", ref.c_str(), 0);
+ if (keyctl_revoke(key_serial) == 0) {
+ SLOGD("Revoked key with serial %ld ref %s\n", key_serial, ref.c_str());
+ } else {
+ SLOGE("Failed to revoke key with serial %ld ref %s: %s\n",
+ key_serial, ref.c_str(), strerror(errno));
+ }
+ int pid = fork();
+ if (pid < 0) {
+ SLOGE("Unable to fork: %s", strerror(errno));
+ return -1;
+ }
+ if (pid == 0) {
+ SLOGD("Forked for secdiscard");
+ execl("/system/bin/secdiscard",
+ "/system/bin/secdiscard",
+ key_path.c_str(),
+ NULL);
+ SLOGE("Unable to launch secdiscard on %s: %s\n", key_path.c_str(),
+ strerror(errno));
+ exit(-1);
+ }
+ // ext4enc:TODO reap the zombie
+ return 0;
+}
diff --git a/Ext4Crypt.h b/Ext4Crypt.h
index 53a26a0..f5c2871 100644
--- a/Ext4Crypt.h
+++ b/Ext4Crypt.h
@@ -18,5 +18,8 @@
char* value, size_t len);
int e4crypt_set_field(const char* path, const char* fieldname,
const char* value);
+int e4crypt_set_user_crypto_policies(const char *path);
+int e4crypt_create_new_user_dir(const char *user_handle, const char *path);
+int e4crypt_delete_user_key(const char *user_handle);
__END_DECLS
diff --git a/cryptfs.c b/cryptfs.c
index a905ff6..1a63a5b 100644
--- a/cryptfs.c
+++ b/cryptfs.c
@@ -3237,7 +3237,9 @@
int cryptfs_changepw(int crypt_type, const char *newpw)
{
if (e4crypt_crypto_complete(DATA_MNT_POINT) == 0) {
- return e4crypt_change_password(DATA_MNT_POINT, crypt_type, newpw);
+ return e4crypt_change_password(DATA_MNT_POINT, crypt_type,
+ crypt_type == CRYPT_TYPE_DEFAULT ? DEFAULT_PASSWORD
+ : newpw);
}
struct crypt_mnt_ftr crypt_ftr;
diff --git a/secdiscard.cpp b/secdiscard.cpp
new file mode 100644
index 0000000..3f4ab2e
--- /dev/null
+++ b/secdiscard.cpp
@@ -0,0 +1,236 @@
+/*
+ * Copyright (C) 2015 The Android Open Source 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 <string>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <linux/fiemap.h>
+
+#define LOG_TAG "secdiscard"
+#include "cutils/log.h"
+
+// Deliberately limit ourselves to wiping small files.
+#define MAX_WIPE_LENGTH 4096
+#define INIT_BUFFER_SIZE 2048
+
+static void usage(char *progname);
+static void destroy_key(const std::string &path);
+static int file_device_range(const std::string &path, uint64_t range[2]);
+static int open_block_device_for_path(const std::string &path);
+static int read_file_as_string_atomically(const std::string &path, std::string &contents);
+static int find_block_device_for_path(
+ const std::string &mounts,
+ const std::string &path,
+ std::string &block_device);
+
+int main(int argc, char **argv) {
+ if (argc != 2 || argv[1][0] != '/') {
+ usage(argv[0]);
+ return -1;
+ }
+ SLOGD("Running: %s %s", argv[0], argv[1]);
+ std::string target(argv[1]);
+ destroy_key(target);
+ if (unlink(argv[1]) != 0 && errno != ENOENT) {
+ SLOGE("Unable to delete %s: %s",
+ argv[1], strerror(errno));
+ return -1;
+ }
+ return 0;
+}
+
+static void usage(char *progname) {
+ fprintf(stderr, "Usage: %s <absolute path>\n", progname);
+}
+
+// BLKSECDISCARD all content in "path", if it's small enough.
+static void destroy_key(const std::string &path) {
+ uint64_t range[2];
+ if (file_device_range(path, range) < 0) {
+ return;
+ }
+ int fs_fd = open_block_device_for_path(path);
+ if (fs_fd < 0) {
+ return;
+ }
+ if (ioctl(fs_fd, BLKSECDISCARD, range) != 0) {
+ SLOGE("Unable to BLKSECDISCARD %s: %s", path.c_str(), strerror(errno));
+ close(fs_fd);
+ return;
+ }
+ close(fs_fd);
+ SLOGD("Discarded %s", path.c_str());
+}
+
+// Find a short range that completely covers the file.
+// If there isn't one, return -1, otherwise 0.
+static int file_device_range(const std::string &path, uint64_t range[2])
+{
+ int fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ if (errno == ENOENT) {
+ SLOGD("Unable to open %s: %s", path.c_str(), strerror(errno));
+ } else {
+ SLOGE("Unable to open %s: %s", path.c_str(), strerror(errno));
+ }
+ return -1;
+ }
+ alignas(struct fiemap) char fiemap_buffer[offsetof(struct fiemap, fm_extents[1])];
+ memset(fiemap_buffer, 0, sizeof(fiemap_buffer));
+ struct fiemap *fiemap = (struct fiemap *)fiemap_buffer;
+ fiemap->fm_start = 0;
+ fiemap->fm_length = UINT64_MAX;
+ fiemap->fm_flags = 0;
+ fiemap->fm_extent_count = 1;
+ fiemap->fm_mapped_extents = 0;
+ if (ioctl(fd, FS_IOC_FIEMAP, fiemap) != 0) {
+ SLOGE("Unable to FIEMAP %s: %s", path.c_str(), strerror(errno));
+ close(fd);
+ return -1;
+ }
+ close(fd);
+ if (fiemap->fm_mapped_extents != 1) {
+ SLOGE("Expecting one extent, got %d in %s", fiemap->fm_mapped_extents, path.c_str());
+ return -1;
+ }
+ struct fiemap_extent *extent = &fiemap->fm_extents[0];
+ if (!(extent->fe_flags & FIEMAP_EXTENT_LAST)) {
+ SLOGE("First extent was not the last in %s", path.c_str());
+ return -1;
+ }
+ if (extent->fe_flags &
+ (FIEMAP_EXTENT_UNKNOWN | FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_NOT_ALIGNED)) {
+ SLOGE("Extent has unexpected flags %ulx: %s", extent->fe_flags, path.c_str());
+ return -1;
+ }
+ if (extent->fe_length > MAX_WIPE_LENGTH) {
+ SLOGE("Extent too big, %llu bytes in %s", extent->fe_length, path.c_str());
+ return -1;
+ }
+ range[0] = extent->fe_physical;
+ range[1] = extent->fe_length;
+ return 0;
+}
+
+// Given a file path, look for the corresponding
+// block device in /proc/mounts and open it.
+static int open_block_device_for_path(const std::string &path)
+{
+ std::string mountsfile("/proc/mounts");
+ std::string mounts;
+ if (read_file_as_string_atomically(mountsfile, mounts) < 0) {
+ return -1;
+ }
+ std::string block_device;
+ if (find_block_device_for_path(mounts, path, block_device) < 0) {
+ return -1;
+ }
+ SLOGD("For path %s block device is %s", path.c_str(), block_device.c_str());
+ int res = open(block_device.c_str(), O_RDWR | O_LARGEFILE | O_CLOEXEC);
+ if (res < 0) {
+ SLOGE("Failed to open device %s: %s", block_device.c_str(), strerror(errno));
+ return -1;
+ }
+ return res;
+}
+
+// Read a file into a buffer in a single gulp, for atomicity.
+// Null-terminate the buffer.
+// Retry until the buffer is big enough.
+static int read_file_as_string_atomically(const std::string &path, std::string &contents)
+{
+ ssize_t buffer_size = INIT_BUFFER_SIZE;
+ while (true) {
+ int fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ SLOGE("Failed to open %s: %s", path.c_str(), strerror(errno));
+ return -1;
+ }
+ contents.resize(buffer_size);
+ ssize_t read_size = read(fd, &contents[0], buffer_size);
+ if (read_size < 0) {
+ SLOGE("Failed to read from %s: %s", path.c_str(), strerror(errno));
+ close(fd);
+ return -1;
+ }
+ close(fd);
+ if (read_size < buffer_size) {
+ contents.resize(read_size);
+ return 0;
+ }
+ SLOGD("%s too big for buffer of size %zu", path.c_str(), buffer_size);
+ buffer_size <<= 1;
+ }
+}
+
+// Search a string representing the contents of /proc/mounts
+// for the mount point of a particular file by prefix matching
+// and return the corresponding block device.
+static int find_block_device_for_path(
+ const std::string &mounts,
+ const std::string &path,
+ std::string &block_device)
+{
+ auto line_begin = mounts.begin();
+ size_t best_prefix = 0;
+ std::string::const_iterator line_end;
+ while (line_begin != mounts.end()) {
+ line_end = std::find(line_begin, mounts.end(), '\n');
+ if (line_end == mounts.end()) {
+ break;
+ }
+ auto device_end = std::find(line_begin, line_end, ' ');
+ if (device_end == line_end) {
+ break;
+ }
+ auto mountpoint_begin = device_end + 1;
+ auto mountpoint_end = std::find(mountpoint_begin, line_end, ' ');
+ if (mountpoint_end == line_end) {
+ break;
+ }
+ if (std::find(line_begin, mountpoint_end, '\\') != mountpoint_end) {
+ // We don't correctly handle escape sequences, and we don't expect
+ // to encounter any, so fail if we do.
+ break;
+ }
+ size_t mountpoint_len = mountpoint_end - mountpoint_begin;
+ if (mountpoint_len > best_prefix &&
+ mountpoint_len < path.length() &&
+ path[mountpoint_len] == '/' &&
+ std::equal(mountpoint_begin, mountpoint_end, path.begin())) {
+ block_device = std::string(line_begin, device_end);
+ best_prefix = mountpoint_len;
+ }
+ line_begin = line_end + 1;
+ }
+ // All of the "break"s above are fatal parse errors.
+ if (line_begin != mounts.end()) {
+ auto bad_line = std::string(line_begin, line_end);
+ SLOGE("Unable to parse line in %s: %s", path.c_str(), bad_line.c_str());
+ return -1;
+ }
+ if (best_prefix == 0) {
+ SLOGE("No prefix found for path: %s", path.c_str());
+ return -1;
+ }
+ return 0;
+}