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platform_system_core/sdcard/sdcard.c
Jeff Sharkey 22b912628e Re-derive permissions after package changes. 
When packages change, existing package-specific directories may have
gained/lost a UID mapping, so we need to update the permissions for
any in-memory nodes.

This allows an app to deliver data for another package before that
package is installed, which is the typical pattern of how OBB files
are delivered.

Also fix bug by re-deriving permissions when files are moved.

Bug: 25399427
Change-Id: I06f38a24ad7dee5f5099ba81429aef03208e5683
2015-12-16 13:08:29 -07:00

1971 lines
63 KiB
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/*
* Copyright (C) 2010 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.
*/
#define LOG_TAG "sdcard"
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/fuse.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/inotify.h>
#include <sys/mount.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <cutils/fs.h>
#include <cutils/hashmap.h>
#include <cutils/log.h>
#include <cutils/multiuser.h>
#include <packagelistparser/packagelistparser.h>
#include <private/android_filesystem_config.h>
/* README
*
* What is this?
*
* sdcard is a program that uses FUSE to emulate FAT-on-sdcard style
* directory permissions (all files are given fixed owner, group, and
* permissions at creation, owner, group, and permissions are not
* changeable, symlinks and hardlinks are not createable, etc.
*
* See usage() for command line options.
*
* It must be run as root, but will drop to requested UID/GID as soon as it
* mounts a filesystem. It will refuse to run if requested UID/GID are zero.
*
* Things I believe to be true:
*
* - ops that return a fuse_entry (LOOKUP, MKNOD, MKDIR, LINK, SYMLINK,
* CREAT) must bump that node's refcount
* - don't forget that FORGET can forget multiple references (req->nlookup)
* - if an op that returns a fuse_entry fails writing the reply to the
* kernel, you must rollback the refcount to reflect the reference the
* kernel did not actually acquire
*
* This daemon can also derive custom filesystem permissions based on directory
* structure when requested. These custom permissions support several features:
*
* - Apps can access their own files in /Android/data/com.example/ without
* requiring any additional GIDs.
* - Separate permissions for protecting directories like Pictures and Music.
* - Multi-user separation on the same physical device.
*/
#define FUSE_TRACE 0
#if FUSE_TRACE
#define TRACE(x...) ALOGD(x)
#else
#define TRACE(x...) do {} while (0)
#endif
#define ERROR(x...) ALOGE(x)
#define FUSE_UNKNOWN_INO 0xffffffff
/* Maximum number of bytes to write in one request. */
#define MAX_WRITE (256 * 1024)
/* Maximum number of bytes to read in one request. */
#define MAX_READ (128 * 1024)
/* Largest possible request.
* The request size is bounded by the maximum size of a FUSE_WRITE request because it has
* the largest possible data payload. */
#define MAX_REQUEST_SIZE (sizeof(struct fuse_in_header) + sizeof(struct fuse_write_in) + MAX_WRITE)
/* Pseudo-error constant used to indicate that no fuse status is needed
* or that a reply has already been written. */
#define NO_STATUS 1
/* Supplementary groups to execute with */
static const gid_t kGroups[1] = { AID_PACKAGE_INFO };
/* Permission mode for a specific node. Controls how file permissions
* are derived for children nodes. */
typedef enum {
/* Nothing special; this node should just inherit from its parent. */
PERM_INHERIT,
/* This node is one level above a normal root; used for legacy layouts
* which use the first level to represent user_id. */
PERM_PRE_ROOT,
/* This node is "/" */
PERM_ROOT,
/* This node is "/Android" */
PERM_ANDROID,
/* This node is "/Android/data" */
PERM_ANDROID_DATA,
/* This node is "/Android/obb" */
PERM_ANDROID_OBB,
/* This node is "/Android/media" */
PERM_ANDROID_MEDIA,
} perm_t;
struct handle {
int fd;
};
struct dirhandle {
DIR *d;
};
struct node {
__u32 refcount;
__u64 nid;
__u64 gen;
/*
* The inode number for this FUSE node. Note that this isn't stable across
* multiple invocations of the FUSE daemon.
*/
__u32 ino;
/* State derived based on current position in hierarchy. */
perm_t perm;
userid_t userid;
uid_t uid;
bool under_android;
struct node *next; /* per-dir sibling list */
struct node *child; /* first contained file by this dir */
struct node *parent; /* containing directory */
size_t namelen;
char *name;
/* If non-null, this is the real name of the file in the underlying storage.
* This may differ from the field "name" only by case.
* strlen(actual_name) will always equal strlen(name), so it is safe to use
* namelen for both fields.
*/
char *actual_name;
/* If non-null, an exact underlying path that should be grafted into this
* position. Used to support things like OBB. */
char* graft_path;
size_t graft_pathlen;
bool deleted;
};
static int str_hash(void *key) {
return hashmapHash(key, strlen(key));
}
/** Test if two string keys are equal ignoring case */
static bool str_icase_equals(void *keyA, void *keyB) {
return strcasecmp(keyA, keyB) == 0;
}
/* Global data for all FUSE mounts */
struct fuse_global {
pthread_mutex_t lock;
uid_t uid;
gid_t gid;
bool multi_user;
char source_path[PATH_MAX];
char obb_path[PATH_MAX];
Hashmap* package_to_appid;
__u64 next_generation;
struct node root;
/* Used to allocate unique inode numbers for fuse nodes. We use
* a simple counter based scheme where inode numbers from deleted
* nodes aren't reused. Note that inode allocations are not stable
* across multiple invocation of the sdcard daemon, but that shouldn't
* be a huge problem in practice.
*
* Note that we restrict inodes to 32 bit unsigned integers to prevent
* truncation on 32 bit processes when unsigned long long stat.st_ino is
* assigned to an unsigned long ino_t type in an LP32 process.
*
* Also note that fuse_attr and fuse_dirent inode values are 64 bits wide
* on both LP32 and LP64, but the fuse kernel code doesn't squash 64 bit
* inode numbers into 32 bit values on 64 bit kernels (see fuse_squash_ino
* in fs/fuse/inode.c).
*
* Accesses must be guarded by |lock|.
*/
__u32 inode_ctr;
struct fuse* fuse_default;
struct fuse* fuse_read;
struct fuse* fuse_write;
};
/* Single FUSE mount */
struct fuse {
struct fuse_global* global;
char dest_path[PATH_MAX];
int fd;
gid_t gid;
mode_t mask;
};
/* Private data used by a single FUSE handler */
struct fuse_handler {
struct fuse* fuse;
int token;
/* To save memory, we never use the contents of the request buffer and the read
* buffer at the same time. This allows us to share the underlying storage. */
union {
__u8 request_buffer[MAX_REQUEST_SIZE];
__u8 read_buffer[MAX_READ + PAGE_SIZE];
};
};
static inline void *id_to_ptr(__u64 nid)
{
return (void *) (uintptr_t) nid;
}
static inline __u64 ptr_to_id(void *ptr)
{
return (__u64) (uintptr_t) ptr;
}
static void acquire_node_locked(struct node* node)
{
node->refcount++;
TRACE("ACQUIRE %p (%s) rc=%d\n", node, node->name, node->refcount);
}
static void remove_node_from_parent_locked(struct node* node);
static void release_node_locked(struct node* node)
{
TRACE("RELEASE %p (%s) rc=%d\n", node, node->name, node->refcount);
if (node->refcount > 0) {
node->refcount--;
if (!node->refcount) {
TRACE("DESTROY %p (%s)\n", node, node->name);
remove_node_from_parent_locked(node);
/* TODO: remove debugging - poison memory */
memset(node->name, 0xef, node->namelen);
free(node->name);
free(node->actual_name);
memset(node, 0xfc, sizeof(*node));
free(node);
}
} else {
ERROR("Zero refcnt %p\n", node);
}
}
static void add_node_to_parent_locked(struct node *node, struct node *parent) {
node->parent = parent;
node->next = parent->child;
parent->child = node;
acquire_node_locked(parent);
}
static void remove_node_from_parent_locked(struct node* node)
{
if (node->parent) {
if (node->parent->child == node) {
node->parent->child = node->parent->child->next;
} else {
struct node *node2;
node2 = node->parent->child;
while (node2->next != node)
node2 = node2->next;
node2->next = node->next;
}
release_node_locked(node->parent);
node->parent = NULL;
node->next = NULL;
}
}
/* Gets the absolute path to a node into the provided buffer.
*
* Populates 'buf' with the path and returns the length of the path on success,
* or returns -1 if the path is too long for the provided buffer.
*/
static ssize_t get_node_path_locked(struct node* node, char* buf, size_t bufsize) {
const char* name;
size_t namelen;
if (node->graft_path) {
name = node->graft_path;
namelen = node->graft_pathlen;
} else if (node->actual_name) {
name = node->actual_name;
namelen = node->namelen;
} else {
name = node->name;
namelen = node->namelen;
}
if (bufsize < namelen + 1) {
return -1;
}
ssize_t pathlen = 0;
if (node->parent && node->graft_path == NULL) {
pathlen = get_node_path_locked(node->parent, buf, bufsize - namelen - 2);
if (pathlen < 0) {
return -1;
}
buf[pathlen++] = '/';
}
memcpy(buf + pathlen, name, namelen + 1); /* include trailing \0 */
return pathlen + namelen;
}
/* Finds the absolute path of a file within a given directory.
* Performs a case-insensitive search for the file and sets the buffer to the path
* of the first matching file. If 'search' is zero or if no match is found, sets
* the buffer to the path that the file would have, assuming the name were case-sensitive.
*
* Populates 'buf' with the path and returns the actual name (within 'buf') on success,
* or returns NULL if the path is too long for the provided buffer.
*/
static char* find_file_within(const char* path, const char* name,
char* buf, size_t bufsize, int search)
{
size_t pathlen = strlen(path);
size_t namelen = strlen(name);
size_t childlen = pathlen + namelen + 1;
char* actual;
if (bufsize <= childlen) {
return NULL;
}
memcpy(buf, path, pathlen);
buf[pathlen] = '/';
actual = buf + pathlen + 1;
memcpy(actual, name, namelen + 1);
if (search && access(buf, F_OK)) {
struct dirent* entry;
DIR* dir = opendir(path);
if (!dir) {
ERROR("opendir %s failed: %s\n", path, strerror(errno));
return actual;
}
while ((entry = readdir(dir))) {
if (!strcasecmp(entry->d_name, name)) {
/* we have a match - replace the name, don't need to copy the null again */
memcpy(actual, entry->d_name, namelen);
break;
}
}
closedir(dir);
}
return actual;
}
static void attr_from_stat(struct fuse* fuse, struct fuse_attr *attr,
const struct stat *s, const struct node* node) {
attr->ino = node->ino;
attr->size = s->st_size;
attr->blocks = s->st_blocks;
attr->atime = s->st_atim.tv_sec;
attr->mtime = s->st_mtim.tv_sec;
attr->ctime = s->st_ctim.tv_sec;
attr->atimensec = s->st_atim.tv_nsec;
attr->mtimensec = s->st_mtim.tv_nsec;
attr->ctimensec = s->st_ctim.tv_nsec;
attr->mode = s->st_mode;
attr->nlink = s->st_nlink;
attr->uid = node->uid;
if (fuse->gid == AID_SDCARD_RW) {
/* As an optimization, certain trusted system components only run
* as owner but operate across all users. Since we're now handing
* out the sdcard_rw GID only to trusted apps, we're okay relaxing
* the user boundary enforcement for the default view. The UIDs
* assigned to app directories are still multiuser aware. */
attr->gid = AID_SDCARD_RW;
} else {
attr->gid = multiuser_get_uid(node->userid, fuse->gid);
}
int visible_mode = 0775 & ~fuse->mask;
if (node->perm == PERM_PRE_ROOT) {
/* Top of multi-user view should always be visible to ensure
* secondary users can traverse inside. */
visible_mode = 0711;
} else if (node->under_android) {
/* Block "other" access to Android directories, since only apps
* belonging to a specific user should be in there; we still
* leave +x open for the default view. */
if (fuse->gid == AID_SDCARD_RW) {
visible_mode = visible_mode & ~0006;
} else {
visible_mode = visible_mode & ~0007;
}
}
int owner_mode = s->st_mode & 0700;
int filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
attr->mode = (attr->mode & S_IFMT) | filtered_mode;
}
static int touch(char* path, mode_t mode) {
int fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, mode);
if (fd == -1) {
if (errno == EEXIST) {
return 0;
} else {
ERROR("Failed to open(%s): %s\n", path, strerror(errno));
return -1;
}
}
close(fd);
return 0;
}
static void derive_permissions_locked(struct fuse* fuse, struct node *parent,
struct node *node) {
appid_t appid;
/* By default, each node inherits from its parent */
node->perm = PERM_INHERIT;
node->userid = parent->userid;
node->uid = parent->uid;
node->under_android = parent->under_android;
/* Derive custom permissions based on parent and current node */
switch (parent->perm) {
case PERM_INHERIT:
/* Already inherited above */
break;
case PERM_PRE_ROOT:
/* Legacy internal layout places users at top level */
node->perm = PERM_ROOT;
node->userid = strtoul(node->name, NULL, 10);
break;
case PERM_ROOT:
/* Assume masked off by default. */
if (!strcasecmp(node->name, "Android")) {
/* App-specific directories inside; let anyone traverse */
node->perm = PERM_ANDROID;
node->under_android = true;
}
break;
case PERM_ANDROID:
if (!strcasecmp(node->name, "data")) {
/* App-specific directories inside; let anyone traverse */
node->perm = PERM_ANDROID_DATA;
} else if (!strcasecmp(node->name, "obb")) {
/* App-specific directories inside; let anyone traverse */
node->perm = PERM_ANDROID_OBB;
/* Single OBB directory is always shared */
node->graft_path = fuse->global->obb_path;
node->graft_pathlen = strlen(fuse->global->obb_path);
} else if (!strcasecmp(node->name, "media")) {
/* App-specific directories inside; let anyone traverse */
node->perm = PERM_ANDROID_MEDIA;
}
break;
case PERM_ANDROID_DATA:
case PERM_ANDROID_OBB:
case PERM_ANDROID_MEDIA:
appid = (appid_t) (uintptr_t) hashmapGet(fuse->global->package_to_appid, node->name);
if (appid != 0) {
node->uid = multiuser_get_uid(parent->userid, appid);
}
break;
}
}
static void derive_permissions_recursive_locked(struct fuse* fuse, struct node *parent) {
struct node *node;
for (node = parent->child; node; node = node->next) {
derive_permissions_locked(fuse, parent, node);
if (node->child) {
derive_permissions_recursive_locked(fuse, node);
}
}
}
/* Kernel has already enforced everything we returned through
* derive_permissions_locked(), so this is used to lock down access
* even further, such as enforcing that apps hold sdcard_rw. */
static bool check_caller_access_to_name(struct fuse* fuse,
const struct fuse_in_header *hdr, const struct node* parent_node,
const char* name, int mode) {
/* Always block security-sensitive files at root */
if (parent_node && parent_node->perm == PERM_ROOT) {
if (!strcasecmp(name, "autorun.inf")
|| !strcasecmp(name, ".android_secure")
|| !strcasecmp(name, "android_secure")) {
return false;
}
}
/* Root always has access; access for any other UIDs should always
* be controlled through packages.list. */
if (hdr->uid == 0) {
return true;
}
/* No extra permissions to enforce */
return true;
}
static bool check_caller_access_to_node(struct fuse* fuse,
const struct fuse_in_header *hdr, const struct node* node, int mode) {
return check_caller_access_to_name(fuse, hdr, node->parent, node->name, mode);
}
struct node *create_node_locked(struct fuse* fuse,
struct node *parent, const char *name, const char* actual_name)
{
struct node *node;
size_t namelen = strlen(name);
// Detect overflows in the inode counter. "4 billion nodes should be enough
// for everybody".
if (fuse->global->inode_ctr == 0) {
ERROR("No more inode numbers available");
return NULL;
}
node = calloc(1, sizeof(struct node));
if (!node) {
return NULL;
}
node->name = malloc(namelen + 1);
if (!node->name) {
free(node);
return NULL;
}
memcpy(node->name, name, namelen + 1);
if (strcmp(name, actual_name)) {
node->actual_name = malloc(namelen + 1);
if (!node->actual_name) {
free(node->name);
free(node);
return NULL;
}
memcpy(node->actual_name, actual_name, namelen + 1);
}
node->namelen = namelen;
node->nid = ptr_to_id(node);
node->ino = fuse->global->inode_ctr++;
node->gen = fuse->global->next_generation++;
node->deleted = false;
derive_permissions_locked(fuse, parent, node);
acquire_node_locked(node);
add_node_to_parent_locked(node, parent);
return node;
}
static int rename_node_locked(struct node *node, const char *name,
const char* actual_name)
{
size_t namelen = strlen(name);
int need_actual_name = strcmp(name, actual_name);
/* make the storage bigger without actually changing the name
* in case an error occurs part way */
if (namelen > node->namelen) {
char* new_name = realloc(node->name, namelen + 1);
if (!new_name) {
return -ENOMEM;
}
node->name = new_name;
if (need_actual_name && node->actual_name) {
char* new_actual_name = realloc(node->actual_name, namelen + 1);
if (!new_actual_name) {
return -ENOMEM;
}
node->actual_name = new_actual_name;
}
}
/* update the name, taking care to allocate storage before overwriting the old name */
if (need_actual_name) {
if (!node->actual_name) {
node->actual_name = malloc(namelen + 1);
if (!node->actual_name) {
return -ENOMEM;
}
}
memcpy(node->actual_name, actual_name, namelen + 1);
} else {
free(node->actual_name);
node->actual_name = NULL;
}
memcpy(node->name, name, namelen + 1);
node->namelen = namelen;
return 0;
}
static struct node *lookup_node_by_id_locked(struct fuse *fuse, __u64 nid)
{
if (nid == FUSE_ROOT_ID) {
return &fuse->global->root;
} else {
return id_to_ptr(nid);
}
}
static struct node* lookup_node_and_path_by_id_locked(struct fuse* fuse, __u64 nid,
char* buf, size_t bufsize)
{
struct node* node = lookup_node_by_id_locked(fuse, nid);
if (node && get_node_path_locked(node, buf, bufsize) < 0) {
node = NULL;
}
return node;
}
static struct node *lookup_child_by_name_locked(struct node *node, const char *name)
{
for (node = node->child; node; node = node->next) {
/* use exact string comparison, nodes that differ by case
* must be considered distinct even if they refer to the same
* underlying file as otherwise operations such as "mv x x"
* will not work because the source and target nodes are the same. */
if (!strcmp(name, node->name) && !node->deleted) {
return node;
}
}
return 0;
}
static struct node* acquire_or_create_child_locked(
struct fuse* fuse, struct node* parent,
const char* name, const char* actual_name)
{
struct node* child = lookup_child_by_name_locked(parent, name);
if (child) {
acquire_node_locked(child);
} else {
child = create_node_locked(fuse, parent, name, actual_name);
}
return child;
}
static void fuse_status(struct fuse *fuse, __u64 unique, int err)
{
struct fuse_out_header hdr;
hdr.len = sizeof(hdr);
hdr.error = err;
hdr.unique = unique;
write(fuse->fd, &hdr, sizeof(hdr));
}
static void fuse_reply(struct fuse *fuse, __u64 unique, void *data, int len)
{
struct fuse_out_header hdr;
struct iovec vec[2];
int res;
hdr.len = len + sizeof(hdr);
hdr.error = 0;
hdr.unique = unique;
vec[0].iov_base = &hdr;
vec[0].iov_len = sizeof(hdr);
vec[1].iov_base = data;
vec[1].iov_len = len;
res = writev(fuse->fd, vec, 2);
if (res < 0) {
ERROR("*** REPLY FAILED *** %d\n", errno);
}
}
static int fuse_reply_entry(struct fuse* fuse, __u64 unique,
struct node* parent, const char* name, const char* actual_name,
const char* path)
{
struct node* node;
struct fuse_entry_out out;
struct stat s;
if (lstat(path, &s) < 0) {
return -errno;
}
pthread_mutex_lock(&fuse->global->lock);
node = acquire_or_create_child_locked(fuse, parent, name, actual_name);
if (!node) {
pthread_mutex_unlock(&fuse->global->lock);
return -ENOMEM;
}
memset(&out, 0, sizeof(out));
attr_from_stat(fuse, &out.attr, &s, node);
out.attr_valid = 10;
out.entry_valid = 10;
out.nodeid = node->nid;
out.generation = node->gen;
pthread_mutex_unlock(&fuse->global->lock);
fuse_reply(fuse, unique, &out, sizeof(out));
return NO_STATUS;
}
static int fuse_reply_attr(struct fuse* fuse, __u64 unique, const struct node* node,
const char* path)
{
struct fuse_attr_out out;
struct stat s;
if (lstat(path, &s) < 0) {
return -errno;
}
memset(&out, 0, sizeof(out));
attr_from_stat(fuse, &out.attr, &s, node);
out.attr_valid = 10;
fuse_reply(fuse, unique, &out, sizeof(out));
return NO_STATUS;
}
static void fuse_notify_delete(struct fuse* fuse, const __u64 parent,
const __u64 child, const char* name) {
struct fuse_out_header hdr;
struct fuse_notify_delete_out data;
struct iovec vec[3];
size_t namelen = strlen(name);
int res;
hdr.len = sizeof(hdr) + sizeof(data) + namelen + 1;
hdr.error = FUSE_NOTIFY_DELETE;
hdr.unique = 0;
data.parent = parent;
data.child = child;
data.namelen = namelen;
data.padding = 0;
vec[0].iov_base = &hdr;
vec[0].iov_len = sizeof(hdr);
vec[1].iov_base = &data;
vec[1].iov_len = sizeof(data);
vec[2].iov_base = (void*) name;
vec[2].iov_len = namelen + 1;
res = writev(fuse->fd, vec, 3);
/* Ignore ENOENT, since other views may not have seen the entry */
if (res < 0 && errno != ENOENT) {
ERROR("*** NOTIFY FAILED *** %d\n", errno);
}
}
static int handle_lookup(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header *hdr, const char* name)
{
struct node* parent_node;
char parent_path[PATH_MAX];
char child_path[PATH_MAX];
const char* actual_name;
pthread_mutex_lock(&fuse->global->lock);
parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid,
parent_path, sizeof(parent_path));
TRACE("[%d] LOOKUP %s @ %"PRIx64" (%s)\n", handler->token, name, hdr->nodeid,
parent_node ? parent_node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!parent_node || !(actual_name = find_file_within(parent_path, name,
child_path, sizeof(child_path), 1))) {
return -ENOENT;
}
if (!check_caller_access_to_name(fuse, hdr, parent_node, name, R_OK)) {
return -EACCES;
}
return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path);
}
static int handle_forget(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header *hdr, const struct fuse_forget_in *req)
{
struct node* node;
pthread_mutex_lock(&fuse->global->lock);
node = lookup_node_by_id_locked(fuse, hdr->nodeid);
TRACE("[%d] FORGET #%"PRIu64" @ %"PRIx64" (%s)\n", handler->token, req->nlookup,
hdr->nodeid, node ? node->name : "?");
if (node) {
__u64 n = req->nlookup;
while (n--) {
release_node_locked(node);
}
}
pthread_mutex_unlock(&fuse->global->lock);
return NO_STATUS; /* no reply */
}
static int handle_getattr(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header *hdr, const struct fuse_getattr_in *req)
{
struct node* node;
char path[PATH_MAX];
pthread_mutex_lock(&fuse->global->lock);
node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path));
TRACE("[%d] GETATTR flags=%x fh=%"PRIx64" @ %"PRIx64" (%s)\n", handler->token,
req->getattr_flags, req->fh, hdr->nodeid, node ? node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!node) {
return -ENOENT;
}
if (!check_caller_access_to_node(fuse, hdr, node, R_OK)) {
return -EACCES;
}
return fuse_reply_attr(fuse, hdr->unique, node, path);
}
static int handle_setattr(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header *hdr, const struct fuse_setattr_in *req)
{
struct node* node;
char path[PATH_MAX];
struct timespec times[2];
pthread_mutex_lock(&fuse->global->lock);
node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path));
TRACE("[%d] SETATTR fh=%"PRIx64" valid=%x @ %"PRIx64" (%s)\n", handler->token,
req->fh, req->valid, hdr->nodeid, node ? node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!node) {
return -ENOENT;
}
if (!(req->valid & FATTR_FH) &&
!check_caller_access_to_node(fuse, hdr, node, W_OK)) {
return -EACCES;
}
/* XXX: incomplete implementation on purpose.
* chmod/chown should NEVER be implemented.*/
if ((req->valid & FATTR_SIZE) && truncate64(path, req->size) < 0) {
return -errno;
}
/* Handle changing atime and mtime. If FATTR_ATIME_and FATTR_ATIME_NOW
* are both set, then set it to the current time. Else, set it to the
* time specified in the request. Same goes for mtime. Use utimensat(2)
* as it allows ATIME and MTIME to be changed independently, and has
* nanosecond resolution which fuse also has.
*/
if (req->valid & (FATTR_ATIME | FATTR_MTIME)) {
times[0].tv_nsec = UTIME_OMIT;
times[1].tv_nsec = UTIME_OMIT;
if (req->valid & FATTR_ATIME) {
if (req->valid & FATTR_ATIME_NOW) {
times[0].tv_nsec = UTIME_NOW;
} else {
times[0].tv_sec = req->atime;
times[0].tv_nsec = req->atimensec;
}
}
if (req->valid & FATTR_MTIME) {
if (req->valid & FATTR_MTIME_NOW) {
times[1].tv_nsec = UTIME_NOW;
} else {
times[1].tv_sec = req->mtime;
times[1].tv_nsec = req->mtimensec;
}
}
TRACE("[%d] Calling utimensat on %s with atime %ld, mtime=%ld\n",
handler->token, path, times[0].tv_sec, times[1].tv_sec);
if (utimensat(-1, path, times, 0) < 0) {
return -errno;
}
}
return fuse_reply_attr(fuse, hdr->unique, node, path);
}
static int handle_mknod(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_mknod_in* req, const char* name)
{
struct node* parent_node;
char parent_path[PATH_MAX];
char child_path[PATH_MAX];
const char* actual_name;
pthread_mutex_lock(&fuse->global->lock);
parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid,
parent_path, sizeof(parent_path));
TRACE("[%d] MKNOD %s 0%o @ %"PRIx64" (%s)\n", handler->token,
name, req->mode, hdr->nodeid, parent_node ? parent_node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!parent_node || !(actual_name = find_file_within(parent_path, name,
child_path, sizeof(child_path), 1))) {
return -ENOENT;
}
if (!check_caller_access_to_name(fuse, hdr, parent_node, name, W_OK)) {
return -EACCES;
}
__u32 mode = (req->mode & (~0777)) | 0664;
if (mknod(child_path, mode, req->rdev) < 0) {
return -errno;
}
return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path);
}
static int handle_mkdir(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_mkdir_in* req, const char* name)
{
struct node* parent_node;
char parent_path[PATH_MAX];
char child_path[PATH_MAX];
const char* actual_name;
pthread_mutex_lock(&fuse->global->lock);
parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid,
parent_path, sizeof(parent_path));
TRACE("[%d] MKDIR %s 0%o @ %"PRIx64" (%s)\n", handler->token,
name, req->mode, hdr->nodeid, parent_node ? parent_node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!parent_node || !(actual_name = find_file_within(parent_path, name,
child_path, sizeof(child_path), 1))) {
return -ENOENT;
}
if (!check_caller_access_to_name(fuse, hdr, parent_node, name, W_OK)) {
return -EACCES;
}
__u32 mode = (req->mode & (~0777)) | 0775;
if (mkdir(child_path, mode) < 0) {
return -errno;
}
/* When creating /Android/data and /Android/obb, mark them as .nomedia */
if (parent_node->perm == PERM_ANDROID && !strcasecmp(name, "data")) {
char nomedia[PATH_MAX];
snprintf(nomedia, PATH_MAX, "%s/.nomedia", child_path);
if (touch(nomedia, 0664) != 0) {
ERROR("Failed to touch(%s): %s\n", nomedia, strerror(errno));
return -ENOENT;
}
}
if (parent_node->perm == PERM_ANDROID && !strcasecmp(name, "obb")) {
char nomedia[PATH_MAX];
snprintf(nomedia, PATH_MAX, "%s/.nomedia", fuse->global->obb_path);
if (touch(nomedia, 0664) != 0) {
ERROR("Failed to touch(%s): %s\n", nomedia, strerror(errno));
return -ENOENT;
}
}
return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path);
}
static int handle_unlink(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const char* name)
{
struct node* parent_node;
struct node* child_node;
char parent_path[PATH_MAX];
char child_path[PATH_MAX];
pthread_mutex_lock(&fuse->global->lock);
parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid,
parent_path, sizeof(parent_path));
TRACE("[%d] UNLINK %s @ %"PRIx64" (%s)\n", handler->token,
name, hdr->nodeid, parent_node ? parent_node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!parent_node || !find_file_within(parent_path, name,
child_path, sizeof(child_path), 1)) {
return -ENOENT;
}
if (!check_caller_access_to_name(fuse, hdr, parent_node, name, W_OK)) {
return -EACCES;
}
if (unlink(child_path) < 0) {
return -errno;
}
pthread_mutex_lock(&fuse->global->lock);
child_node = lookup_child_by_name_locked(parent_node, name);
if (child_node) {
child_node->deleted = true;
}
pthread_mutex_unlock(&fuse->global->lock);
if (parent_node && child_node) {
/* Tell all other views that node is gone */
TRACE("[%d] fuse_notify_delete parent=%"PRIx64", child=%"PRIx64", name=%s\n",
handler->token, (uint64_t) parent_node->nid, (uint64_t) child_node->nid, name);
if (fuse != fuse->global->fuse_default) {
fuse_notify_delete(fuse->global->fuse_default, parent_node->nid, child_node->nid, name);
}
if (fuse != fuse->global->fuse_read) {
fuse_notify_delete(fuse->global->fuse_read, parent_node->nid, child_node->nid, name);
}
if (fuse != fuse->global->fuse_write) {
fuse_notify_delete(fuse->global->fuse_write, parent_node->nid, child_node->nid, name);
}
}
return 0;
}
static int handle_rmdir(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const char* name)
{
struct node* child_node;
struct node* parent_node;
char parent_path[PATH_MAX];
char child_path[PATH_MAX];
pthread_mutex_lock(&fuse->global->lock);
parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid,
parent_path, sizeof(parent_path));
TRACE("[%d] RMDIR %s @ %"PRIx64" (%s)\n", handler->token,
name, hdr->nodeid, parent_node ? parent_node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!parent_node || !find_file_within(parent_path, name,
child_path, sizeof(child_path), 1)) {
return -ENOENT;
}
if (!check_caller_access_to_name(fuse, hdr, parent_node, name, W_OK)) {
return -EACCES;
}
if (rmdir(child_path) < 0) {
return -errno;
}
pthread_mutex_lock(&fuse->global->lock);
child_node = lookup_child_by_name_locked(parent_node, name);
if (child_node) {
child_node->deleted = true;
}
pthread_mutex_unlock(&fuse->global->lock);
if (parent_node && child_node) {
/* Tell all other views that node is gone */
TRACE("[%d] fuse_notify_delete parent=%"PRIx64", child=%"PRIx64", name=%s\n",
handler->token, (uint64_t) parent_node->nid, (uint64_t) child_node->nid, name);
if (fuse != fuse->global->fuse_default) {
fuse_notify_delete(fuse->global->fuse_default, parent_node->nid, child_node->nid, name);
}
if (fuse != fuse->global->fuse_read) {
fuse_notify_delete(fuse->global->fuse_read, parent_node->nid, child_node->nid, name);
}
if (fuse != fuse->global->fuse_write) {
fuse_notify_delete(fuse->global->fuse_write, parent_node->nid, child_node->nid, name);
}
}
return 0;
}
static int handle_rename(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_rename_in* req,
const char* old_name, const char* new_name)
{
struct node* old_parent_node;
struct node* new_parent_node;
struct node* child_node;
char old_parent_path[PATH_MAX];
char new_parent_path[PATH_MAX];
char old_child_path[PATH_MAX];
char new_child_path[PATH_MAX];
const char* new_actual_name;
int res;
pthread_mutex_lock(&fuse->global->lock);
old_parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid,
old_parent_path, sizeof(old_parent_path));
new_parent_node = lookup_node_and_path_by_id_locked(fuse, req->newdir,
new_parent_path, sizeof(new_parent_path));
TRACE("[%d] RENAME %s->%s @ %"PRIx64" (%s) -> %"PRIx64" (%s)\n", handler->token,
old_name, new_name,
hdr->nodeid, old_parent_node ? old_parent_node->name : "?",
req->newdir, new_parent_node ? new_parent_node->name : "?");
if (!old_parent_node || !new_parent_node) {
res = -ENOENT;
goto lookup_error;
}
if (!check_caller_access_to_name(fuse, hdr, old_parent_node, old_name, W_OK)) {
res = -EACCES;
goto lookup_error;
}
if (!check_caller_access_to_name(fuse, hdr, new_parent_node, new_name, W_OK)) {
res = -EACCES;
goto lookup_error;
}
child_node = lookup_child_by_name_locked(old_parent_node, old_name);
if (!child_node || get_node_path_locked(child_node,
old_child_path, sizeof(old_child_path)) < 0) {
res = -ENOENT;
goto lookup_error;
}
acquire_node_locked(child_node);
pthread_mutex_unlock(&fuse->global->lock);
/* Special case for renaming a file where destination is same path
* differing only by case. In this case we don't want to look for a case
* insensitive match. This allows commands like "mv foo FOO" to work as expected.
*/
int search = old_parent_node != new_parent_node
|| strcasecmp(old_name, new_name);
if (!(new_actual_name = find_file_within(new_parent_path, new_name,
new_child_path, sizeof(new_child_path), search))) {
res = -ENOENT;
goto io_error;
}
TRACE("[%d] RENAME %s->%s\n", handler->token, old_child_path, new_child_path);
res = rename(old_child_path, new_child_path);
if (res < 0) {
res = -errno;
goto io_error;
}
pthread_mutex_lock(&fuse->global->lock);
res = rename_node_locked(child_node, new_name, new_actual_name);
if (!res) {
remove_node_from_parent_locked(child_node);
derive_permissions_locked(fuse, new_parent_node, child_node);
derive_permissions_recursive_locked(fuse, child_node);
add_node_to_parent_locked(child_node, new_parent_node);
}
goto done;
io_error:
pthread_mutex_lock(&fuse->global->lock);
done:
release_node_locked(child_node);
lookup_error:
pthread_mutex_unlock(&fuse->global->lock);
return res;
}
static int open_flags_to_access_mode(int open_flags) {
if ((open_flags & O_ACCMODE) == O_RDONLY) {
return R_OK;
} else if ((open_flags & O_ACCMODE) == O_WRONLY) {
return W_OK;
} else {
/* Probably O_RDRW, but treat as default to be safe */
return R_OK | W_OK;
}
}
static int handle_open(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_open_in* req)
{
struct node* node;
char path[PATH_MAX];
struct fuse_open_out out;
struct handle *h;
pthread_mutex_lock(&fuse->global->lock);
node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path));
TRACE("[%d] OPEN 0%o @ %"PRIx64" (%s)\n", handler->token,
req->flags, hdr->nodeid, node ? node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!node) {
return -ENOENT;
}
if (!check_caller_access_to_node(fuse, hdr, node,
open_flags_to_access_mode(req->flags))) {
return -EACCES;
}
h = malloc(sizeof(*h));
if (!h) {
return -ENOMEM;
}
TRACE("[%d] OPEN %s\n", handler->token, path);
h->fd = open(path, req->flags);
if (h->fd < 0) {
free(h);
return -errno;
}
out.fh = ptr_to_id(h);
out.open_flags = 0;
out.padding = 0;
fuse_reply(fuse, hdr->unique, &out, sizeof(out));
return NO_STATUS;
}
static int handle_read(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_read_in* req)
{
struct handle *h = id_to_ptr(req->fh);
__u64 unique = hdr->unique;
__u32 size = req->size;
__u64 offset = req->offset;
int res;
__u8 *read_buffer = (__u8 *) ((uintptr_t)(handler->read_buffer + PAGE_SIZE) & ~((uintptr_t)PAGE_SIZE-1));
/* Don't access any other fields of hdr or req beyond this point, the read buffer
* overlaps the request buffer and will clobber data in the request. This
* saves us 128KB per request handler thread at the cost of this scary comment. */
TRACE("[%d] READ %p(%d) %u@%"PRIu64"\n", handler->token,
h, h->fd, size, (uint64_t) offset);
if (size > MAX_READ) {
return -EINVAL;
}
res = pread64(h->fd, read_buffer, size, offset);
if (res < 0) {
return -errno;
}
fuse_reply(fuse, unique, read_buffer, res);
return NO_STATUS;
}
static int handle_write(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_write_in* req,
const void* buffer)
{
struct fuse_write_out out;
struct handle *h = id_to_ptr(req->fh);
int res;
__u8 aligned_buffer[req->size] __attribute__((__aligned__(PAGE_SIZE)));
if (req->flags & O_DIRECT) {
memcpy(aligned_buffer, buffer, req->size);
buffer = (const __u8*) aligned_buffer;
}
TRACE("[%d] WRITE %p(%d) %u@%"PRIu64"\n", handler->token,
h, h->fd, req->size, req->offset);
res = pwrite64(h->fd, buffer, req->size, req->offset);
if (res < 0) {
return -errno;
}
out.size = res;
out.padding = 0;
fuse_reply(fuse, hdr->unique, &out, sizeof(out));
return NO_STATUS;
}
static int handle_statfs(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr)
{
char path[PATH_MAX];
struct statfs stat;
struct fuse_statfs_out out;
int res;
pthread_mutex_lock(&fuse->global->lock);
TRACE("[%d] STATFS\n", handler->token);
res = get_node_path_locked(&fuse->global->root, path, sizeof(path));
pthread_mutex_unlock(&fuse->global->lock);
if (res < 0) {
return -ENOENT;
}
if (statfs(fuse->global->root.name, &stat) < 0) {
return -errno;
}
memset(&out, 0, sizeof(out));
out.st.blocks = stat.f_blocks;
out.st.bfree = stat.f_bfree;
out.st.bavail = stat.f_bavail;
out.st.files = stat.f_files;
out.st.ffree = stat.f_ffree;
out.st.bsize = stat.f_bsize;
out.st.namelen = stat.f_namelen;
out.st.frsize = stat.f_frsize;
fuse_reply(fuse, hdr->unique, &out, sizeof(out));
return NO_STATUS;
}
static int handle_release(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_release_in* req)
{
struct handle *h = id_to_ptr(req->fh);
TRACE("[%d] RELEASE %p(%d)\n", handler->token, h, h->fd);
close(h->fd);
free(h);
return 0;
}
static int handle_fsync(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_fsync_in* req)
{
bool is_dir = (hdr->opcode == FUSE_FSYNCDIR);
bool is_data_sync = req->fsync_flags & 1;
int fd = -1;
if (is_dir) {
struct dirhandle *dh = id_to_ptr(req->fh);
fd = dirfd(dh->d);
} else {
struct handle *h = id_to_ptr(req->fh);
fd = h->fd;
}
TRACE("[%d] %s %p(%d) is_data_sync=%d\n", handler->token,
is_dir ? "FSYNCDIR" : "FSYNC",
id_to_ptr(req->fh), fd, is_data_sync);
int res = is_data_sync ? fdatasync(fd) : fsync(fd);
if (res == -1) {
return -errno;
}
return 0;
}
static int handle_flush(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr)
{
TRACE("[%d] FLUSH\n", handler->token);
return 0;
}
static int handle_opendir(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_open_in* req)
{
struct node* node;
char path[PATH_MAX];
struct fuse_open_out out;
struct dirhandle *h;
pthread_mutex_lock(&fuse->global->lock);
node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path));
TRACE("[%d] OPENDIR @ %"PRIx64" (%s)\n", handler->token,
hdr->nodeid, node ? node->name : "?");
pthread_mutex_unlock(&fuse->global->lock);
if (!node) {
return -ENOENT;
}
if (!check_caller_access_to_node(fuse, hdr, node, R_OK)) {
return -EACCES;
}
h = malloc(sizeof(*h));
if (!h) {
return -ENOMEM;
}
TRACE("[%d] OPENDIR %s\n", handler->token, path);
h->d = opendir(path);
if (!h->d) {
free(h);
return -errno;
}
out.fh = ptr_to_id(h);
out.open_flags = 0;
out.padding = 0;
fuse_reply(fuse, hdr->unique, &out, sizeof(out));
return NO_STATUS;
}
static int handle_readdir(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_read_in* req)
{
char buffer[8192];
struct fuse_dirent *fde = (struct fuse_dirent*) buffer;
struct dirent *de;
struct dirhandle *h = id_to_ptr(req->fh);
TRACE("[%d] READDIR %p\n", handler->token, h);
if (req->offset == 0) {
/* rewinddir() might have been called above us, so rewind here too */
TRACE("[%d] calling rewinddir()\n", handler->token);
rewinddir(h->d);
}
de = readdir(h->d);
if (!de) {
return 0;
}
fde->ino = FUSE_UNKNOWN_INO;
/* increment the offset so we can detect when rewinddir() seeks back to the beginning */
fde->off = req->offset + 1;
fde->type = de->d_type;
fde->namelen = strlen(de->d_name);
memcpy(fde->name, de->d_name, fde->namelen + 1);
fuse_reply(fuse, hdr->unique, fde,
FUSE_DIRENT_ALIGN(sizeof(struct fuse_dirent) + fde->namelen));
return NO_STATUS;
}
static int handle_releasedir(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_release_in* req)
{
struct dirhandle *h = id_to_ptr(req->fh);
TRACE("[%d] RELEASEDIR %p\n", handler->token, h);
closedir(h->d);
free(h);
return 0;
}
static int handle_init(struct fuse* fuse, struct fuse_handler* handler,
const struct fuse_in_header* hdr, const struct fuse_init_in* req)
{
struct fuse_init_out out;
size_t fuse_struct_size;
TRACE("[%d] INIT ver=%d.%d maxread=%d flags=%x\n",
handler->token, req->major, req->minor, req->max_readahead, req->flags);
/* Kernel 2.6.16 is the first stable kernel with struct fuse_init_out
* defined (fuse version 7.6). The structure is the same from 7.6 through
* 7.22. Beginning with 7.23, the structure increased in size and added
* new parameters.
*/
if (req->major != FUSE_KERNEL_VERSION || req->minor < 6) {
ERROR("Fuse kernel version mismatch: Kernel version %d.%d, Expected at least %d.6",
req->major, req->minor, FUSE_KERNEL_VERSION);
return -1;
}
/* We limit ourselves to 15 because we don't handle BATCH_FORGET yet */
out.minor = MIN(req->minor, 15);
fuse_struct_size = sizeof(out);
#if defined(FUSE_COMPAT_22_INIT_OUT_SIZE)
/* FUSE_KERNEL_VERSION >= 23. */
/* If the kernel only works on minor revs older than or equal to 22,
* then use the older structure size since this code only uses the 7.22
* version of the structure. */
if (req->minor <= 22) {
fuse_struct_size = FUSE_COMPAT_22_INIT_OUT_SIZE;
}
#endif
out.major = FUSE_KERNEL_VERSION;
out.max_readahead = req->max_readahead;
out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES;
out.max_background = 32;
out.congestion_threshold = 32;
out.max_write = MAX_WRITE;
fuse_reply(fuse, hdr->unique, &out, fuse_struct_size);
return NO_STATUS;
}
static int handle_fuse_request(struct fuse *fuse, struct fuse_handler* handler,
const struct fuse_in_header *hdr, const void *data, size_t data_len)
{
switch (hdr->opcode) {
case FUSE_LOOKUP: { /* bytez[] -> entry_out */
const char* name = data;
return handle_lookup(fuse, handler, hdr, name);
}
case FUSE_FORGET: {
const struct fuse_forget_in *req = data;
return handle_forget(fuse, handler, hdr, req);
}
case FUSE_GETATTR: { /* getattr_in -> attr_out */
const struct fuse_getattr_in *req = data;
return handle_getattr(fuse, handler, hdr, req);
}
case FUSE_SETATTR: { /* setattr_in -> attr_out */
const struct fuse_setattr_in *req = data;
return handle_setattr(fuse, handler, hdr, req);
}
// case FUSE_READLINK:
// case FUSE_SYMLINK:
case FUSE_MKNOD: { /* mknod_in, bytez[] -> entry_out */
const struct fuse_mknod_in *req = data;
const char *name = ((const char*) data) + sizeof(*req);
return handle_mknod(fuse, handler, hdr, req, name);
}
case FUSE_MKDIR: { /* mkdir_in, bytez[] -> entry_out */
const struct fuse_mkdir_in *req = data;
const char *name = ((const char*) data) + sizeof(*req);
return handle_mkdir(fuse, handler, hdr, req, name);
}
case FUSE_UNLINK: { /* bytez[] -> */
const char* name = data;
return handle_unlink(fuse, handler, hdr, name);
}
case FUSE_RMDIR: { /* bytez[] -> */
const char* name = data;
return handle_rmdir(fuse, handler, hdr, name);
}
case FUSE_RENAME: { /* rename_in, oldname, newname -> */
const struct fuse_rename_in *req = data;
const char *old_name = ((const char*) data) + sizeof(*req);
const char *new_name = old_name + strlen(old_name) + 1;
return handle_rename(fuse, handler, hdr, req, old_name, new_name);
}
// case FUSE_LINK:
case FUSE_OPEN: { /* open_in -> open_out */
const struct fuse_open_in *req = data;
return handle_open(fuse, handler, hdr, req);
}
case FUSE_READ: { /* read_in -> byte[] */
const struct fuse_read_in *req = data;
return handle_read(fuse, handler, hdr, req);
}
case FUSE_WRITE: { /* write_in, byte[write_in.size] -> write_out */
const struct fuse_write_in *req = data;
const void* buffer = (const __u8*)data + sizeof(*req);
return handle_write(fuse, handler, hdr, req, buffer);
}
case FUSE_STATFS: { /* getattr_in -> attr_out */
return handle_statfs(fuse, handler, hdr);
}
case FUSE_RELEASE: { /* release_in -> */
const struct fuse_release_in *req = data;
return handle_release(fuse, handler, hdr, req);
}
case FUSE_FSYNC:
case FUSE_FSYNCDIR: {
const struct fuse_fsync_in *req = data;
return handle_fsync(fuse, handler, hdr, req);
}
// case FUSE_SETXATTR:
// case FUSE_GETXATTR:
// case FUSE_LISTXATTR:
// case FUSE_REMOVEXATTR:
case FUSE_FLUSH: {
return handle_flush(fuse, handler, hdr);
}
case FUSE_OPENDIR: { /* open_in -> open_out */
const struct fuse_open_in *req = data;
return handle_opendir(fuse, handler, hdr, req);
}
case FUSE_READDIR: {
const struct fuse_read_in *req = data;
return handle_readdir(fuse, handler, hdr, req);
}
case FUSE_RELEASEDIR: { /* release_in -> */
const struct fuse_release_in *req = data;
return handle_releasedir(fuse, handler, hdr, req);
}
case FUSE_INIT: { /* init_in -> init_out */
const struct fuse_init_in *req = data;
return handle_init(fuse, handler, hdr, req);
}
default: {
TRACE("[%d] NOTIMPL op=%d uniq=%"PRIx64" nid=%"PRIx64"\n",
handler->token, hdr->opcode, hdr->unique, hdr->nodeid);
return -ENOSYS;
}
}
}
static void handle_fuse_requests(struct fuse_handler* handler)
{
struct fuse* fuse = handler->fuse;
for (;;) {
ssize_t len = TEMP_FAILURE_RETRY(read(fuse->fd,
handler->request_buffer, sizeof(handler->request_buffer)));
if (len < 0) {
if (errno == ENODEV) {
ERROR("[%d] someone stole our marbles!\n", handler->token);
exit(2);
}
ERROR("[%d] handle_fuse_requests: errno=%d\n", handler->token, errno);
continue;
}
if ((size_t)len < sizeof(struct fuse_in_header)) {
ERROR("[%d] request too short: len=%zu\n", handler->token, (size_t)len);
continue;
}
const struct fuse_in_header *hdr = (void*)handler->request_buffer;
if (hdr->len != (size_t)len) {
ERROR("[%d] malformed header: len=%zu, hdr->len=%u\n",
handler->token, (size_t)len, hdr->len);
continue;
}
const void *data = handler->request_buffer + sizeof(struct fuse_in_header);
size_t data_len = len - sizeof(struct fuse_in_header);
__u64 unique = hdr->unique;
int res = handle_fuse_request(fuse, handler, hdr, data, data_len);
/* We do not access the request again after this point because the underlying
* buffer storage may have been reused while processing the request. */
if (res != NO_STATUS) {
if (res) {
TRACE("[%d] ERROR %d\n", handler->token, res);
}
fuse_status(fuse, unique, res);
}
}
}
static void* start_handler(void* data)
{
struct fuse_handler* handler = data;
handle_fuse_requests(handler);
return NULL;
}
static bool remove_str_to_int(void *key, void *value, void *context) {
Hashmap* map = context;
hashmapRemove(map, key);
free(key);
return true;
}
static bool package_parse_callback(pkg_info *info, void *userdata) {
struct fuse_global *global = (struct fuse_global *)userdata;
char* name = strdup(info->name);
hashmapPut(global->package_to_appid, name, (void*) (uintptr_t) info->uid);
packagelist_free(info);
return true;
}
static bool read_package_list(struct fuse_global* global) {
pthread_mutex_lock(&global->lock);
hashmapForEach(global->package_to_appid, remove_str_to_int, global->package_to_appid);
bool rc = packagelist_parse(package_parse_callback, global);
TRACE("read_package_list: found %zu packages\n",
hashmapSize(global->package_to_appid));
/* Regenerate ownership details using newly loaded mapping */
derive_permissions_recursive_locked(global->fuse_default, &global->root);
pthread_mutex_unlock(&global->lock);
return rc;
}
static void watch_package_list(struct fuse_global* global) {
struct inotify_event *event;
char event_buf[512];
int nfd = inotify_init();
if (nfd < 0) {
ERROR("inotify_init failed: %s\n", strerror(errno));
return;
}
bool active = false;
while (1) {
if (!active) {
int res = inotify_add_watch(nfd, PACKAGES_LIST_FILE, IN_DELETE_SELF);
if (res == -1) {
if (errno == ENOENT || errno == EACCES) {
/* Framework may not have created yet, sleep and retry */
ERROR("missing \"%s\"; retrying\n", PACKAGES_LIST_FILE);
sleep(3);
continue;
} else {
ERROR("inotify_add_watch failed: %s\n", strerror(errno));
return;
}
}
/* Watch above will tell us about any future changes, so
* read the current state. */
if (read_package_list(global) == false) {
ERROR("read_package_list failed\n");
return;
}
active = true;
}
int event_pos = 0;
int res = read(nfd, event_buf, sizeof(event_buf));
if (res < (int) sizeof(*event)) {
if (errno == EINTR)
continue;
ERROR("failed to read inotify event: %s\n", strerror(errno));
return;
}
while (res >= (int) sizeof(*event)) {
int event_size;
event = (struct inotify_event *) (event_buf + event_pos);
TRACE("inotify event: %08x\n", event->mask);
if ((event->mask & IN_IGNORED) == IN_IGNORED) {
/* Previously watched file was deleted, probably due to move
* that swapped in new data; re-arm the watch and read. */
active = false;
}
event_size = sizeof(*event) + event->len;
res -= event_size;
event_pos += event_size;
}
}
}
static int usage() {
ERROR("usage: sdcard [OPTIONS] <source_path> <label>\n"
" -u: specify UID to run as\n"
" -g: specify GID to run as\n"
" -U: specify user ID that owns device\n"
" -m: source_path is multi-user\n"
" -w: runtime write mount has full write access\n"
"\n");
return 1;
}
static int fuse_setup(struct fuse* fuse, gid_t gid, mode_t mask) {
char opts[256];
fuse->fd = open("/dev/fuse", O_RDWR);
if (fuse->fd == -1) {
ERROR("failed to open fuse device: %s\n", strerror(errno));
return -1;
}
umount2(fuse->dest_path, MNT_DETACH);
snprintf(opts, sizeof(opts),
"fd=%i,rootmode=40000,default_permissions,allow_other,user_id=%d,group_id=%d",
fuse->fd, fuse->global->uid, fuse->global->gid);
if (mount("/dev/fuse", fuse->dest_path, "fuse", MS_NOSUID | MS_NODEV | MS_NOEXEC |
MS_NOATIME, opts) != 0) {
ERROR("failed to mount fuse filesystem: %s\n", strerror(errno));
return -1;
}
fuse->gid = gid;
fuse->mask = mask;
return 0;
}
static void run(const char* source_path, const char* label, uid_t uid,
gid_t gid, userid_t userid, bool multi_user, bool full_write) {
struct fuse_global global;
struct fuse fuse_default;
struct fuse fuse_read;
struct fuse fuse_write;
struct fuse_handler handler_default;
struct fuse_handler handler_read;
struct fuse_handler handler_write;
pthread_t thread_default;
pthread_t thread_read;
pthread_t thread_write;
memset(&global, 0, sizeof(global));
memset(&fuse_default, 0, sizeof(fuse_default));
memset(&fuse_read, 0, sizeof(fuse_read));
memset(&fuse_write, 0, sizeof(fuse_write));
memset(&handler_default, 0, sizeof(handler_default));
memset(&handler_read, 0, sizeof(handler_read));
memset(&handler_write, 0, sizeof(handler_write));
pthread_mutex_init(&global.lock, NULL);
global.package_to_appid = hashmapCreate(256, str_hash, str_icase_equals);
global.uid = uid;
global.gid = gid;
global.multi_user = multi_user;
global.next_generation = 0;
global.inode_ctr = 1;
memset(&global.root, 0, sizeof(global.root));
global.root.nid = FUSE_ROOT_ID; /* 1 */
global.root.refcount = 2;
global.root.namelen = strlen(source_path);
global.root.name = strdup(source_path);
global.root.userid = userid;
global.root.uid = AID_ROOT;
global.root.under_android = false;
strcpy(global.source_path, source_path);
if (multi_user) {
global.root.perm = PERM_PRE_ROOT;
snprintf(global.obb_path, sizeof(global.obb_path), "%s/obb", source_path);
} else {
global.root.perm = PERM_ROOT;
snprintf(global.obb_path, sizeof(global.obb_path), "%s/Android/obb", source_path);
}
fuse_default.global = &global;
fuse_read.global = &global;
fuse_write.global = &global;
global.fuse_default = &fuse_default;
global.fuse_read = &fuse_read;
global.fuse_write = &fuse_write;
snprintf(fuse_default.dest_path, PATH_MAX, "/mnt/runtime/default/%s", label);
snprintf(fuse_read.dest_path, PATH_MAX, "/mnt/runtime/read/%s", label);
snprintf(fuse_write.dest_path, PATH_MAX, "/mnt/runtime/write/%s", label);
handler_default.fuse = &fuse_default;
handler_read.fuse = &fuse_read;
handler_write.fuse = &fuse_write;
handler_default.token = 0;
handler_read.token = 1;
handler_write.token = 2;
umask(0);
if (multi_user) {
/* Multi-user storage is fully isolated per user, so "other"
* permissions are completely masked off. */
if (fuse_setup(&fuse_default, AID_SDCARD_RW, 0006)
|| fuse_setup(&fuse_read, AID_EVERYBODY, 0027)
|| fuse_setup(&fuse_write, AID_EVERYBODY, full_write ? 0007 : 0027)) {
ERROR("failed to fuse_setup\n");
exit(1);
}
} else {
/* Physical storage is readable by all users on device, but
* the Android directories are masked off to a single user
* deep inside attr_from_stat(). */
if (fuse_setup(&fuse_default, AID_SDCARD_RW, 0006)
|| fuse_setup(&fuse_read, AID_EVERYBODY, full_write ? 0027 : 0022)
|| fuse_setup(&fuse_write, AID_EVERYBODY, full_write ? 0007 : 0022)) {
ERROR("failed to fuse_setup\n");
exit(1);
}
}
/* Drop privs */
if (setgroups(sizeof(kGroups) / sizeof(kGroups[0]), kGroups) < 0) {
ERROR("cannot setgroups: %s\n", strerror(errno));
exit(1);
}
if (setgid(gid) < 0) {
ERROR("cannot setgid: %s\n", strerror(errno));
exit(1);
}
if (setuid(uid) < 0) {
ERROR("cannot setuid: %s\n", strerror(errno));
exit(1);
}
if (multi_user) {
fs_prepare_dir(global.obb_path, 0775, uid, gid);
}
if (pthread_create(&thread_default, NULL, start_handler, &handler_default)
|| pthread_create(&thread_read, NULL, start_handler, &handler_read)
|| pthread_create(&thread_write, NULL, start_handler, &handler_write)) {
ERROR("failed to pthread_create\n");
exit(1);
}
watch_package_list(&global);
ERROR("terminated prematurely\n");
exit(1);
}
int main(int argc, char **argv) {
const char *source_path = NULL;
const char *label = NULL;
uid_t uid = 0;
gid_t gid = 0;
userid_t userid = 0;
bool multi_user = false;
bool full_write = false;
int i;
struct rlimit rlim;
int fs_version;
int opt;
while ((opt = getopt(argc, argv, "u:g:U:mw")) != -1) {
switch (opt) {
case 'u':
uid = strtoul(optarg, NULL, 10);
break;
case 'g':
gid = strtoul(optarg, NULL, 10);
break;
case 'U':
userid = strtoul(optarg, NULL, 10);
break;
case 'm':
multi_user = true;
break;
case 'w':
full_write = true;
break;
case '?':
default:
return usage();
}
}
for (i = optind; i < argc; i++) {
char* arg = argv[i];
if (!source_path) {
source_path = arg;
} else if (!label) {
label = arg;
} else {
ERROR("too many arguments\n");
return usage();
}
}
if (!source_path) {
ERROR("no source path specified\n");
return usage();
}
if (!label) {
ERROR("no label specified\n");
return usage();
}
if (!uid || !gid) {
ERROR("uid and gid must be nonzero\n");
return usage();
}
rlim.rlim_cur = 8192;
rlim.rlim_max = 8192;
if (setrlimit(RLIMIT_NOFILE, &rlim)) {
ERROR("Error setting RLIMIT_NOFILE, errno = %d\n", errno);
}
while ((fs_read_atomic_int("/data/.layout_version", &fs_version) == -1) || (fs_version < 3)) {
ERROR("installd fs upgrade not yet complete. Waiting...\n");
sleep(1);
}
run(source_path, label, uid, gid, userid, multi_user, full_write);
return 1;
}
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