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sdcard : inode numbers must be fully representable as uint32_t.

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This works around a bug on on 64 bit kernels + sdcard daemons
where we were using memory addresses as inode numbers.

bug: 19012244

(cherry picked from commit faa0935ffb)

Change-Id: Idbf9e285e507e702e04e7461a10153df68ef2322
This commit is contained in:
Narayan Kamath 2015-01-13 18:21:10 +00:00
parent 227f8bf147
commit 5aadceb56f
1 changed files with 34 additions and 1 deletions
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35
sdcard/sdcard.c
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@ -169,6 +169,11 @@ 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;
@ -225,6 +230,25 @@ struct fuse {
struct node root;
char obbpath[PATH_MAX];
/* 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;
Hashmap* package_to_appid;
Hashmap* appid_with_rw;
};
@ -388,7 +412,7 @@ static char* find_file_within(const char* path, const char* name,
static void attr_from_stat(struct fuse_attr *attr, const struct stat *s, const struct node* node)
{
attr->ino = node->nid;
attr->ino = node->ino;
attr->size = s->st_size;
attr->blocks = s->st_blocks;
attr->atime = s->st_atim.tv_sec;
@ -576,6 +600,13 @@ struct node *create_node_locked(struct fuse* fuse,
struct node *node;
size_t namelen = strlen(name);
// Detect overflows in the inode counter. "4 billion nodes should be enough
// for everybody".
if (fuse->inode_ctr == 0) {
ERROR("No more inode numbers available");
return NULL;
}
node = calloc(1, sizeof(struct node));
if (!node) {
return NULL;
@ -597,6 +628,7 @@ struct node *create_node_locked(struct fuse* fuse,
}
node->namelen = namelen;
node->nid = ptr_to_id(node);
node->ino = fuse->inode_ctr++;
node->gen = fuse->next_generation++;
derive_permissions_locked(fuse, parent, node);
@ -701,6 +733,7 @@ static void fuse_init(struct fuse *fuse, int fd, const char *source_path,
fuse->derive = derive;
fuse->split_perms = split_perms;
fuse->write_gid = write_gid;
fuse->inode_ctr = 1;
memset(&fuse->root, 0, sizeof(fuse->root));
fuse->root.nid = FUSE_ROOT_ID; /* 1 */