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virtiofsd: passthrough_ll: add dirp_map to hide lo_dirp pointers

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Do not expose lo_dirp pointers to clients.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2019-01-31 14:01:28 +08:00 committed by Dr. David Alan Gilbert
parent 92fb57b83c
commit b39bce121b
1 changed files with 76 additions and 27 deletions
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103
tools/virtiofsd/passthrough_ll.c
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@ -56,27 +56,10 @@
#include "passthrough_helpers.h"
/*
* We are re-using pointers to our `struct lo_inode`
* elements as inodes. This means that we must be able to
* store uintptr_t values in a fuse_ino_t variable. The following
* incantation checks this condition at compile time.
*/
#if defined(__GNUC__) && \
(__GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__ >= 6) && \
!defined __cplusplus
_Static_assert(sizeof(fuse_ino_t) >= sizeof(uintptr_t),
"fuse_ino_t too small to hold uintptr_t values!");
#else
struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct {
unsigned _uintptr_to_must_hold_fuse_ino_t
: ((sizeof(fuse_ino_t) >= sizeof(uintptr_t)) ? 1 : -1);
};
#endif
struct lo_map_elem {
union {
struct lo_inode *inode;
struct lo_dirp *dirp;
ssize_t freelist;
};
bool in_use;
@ -123,6 +106,7 @@ struct lo_data {
int timeout_set;
struct lo_inode root; /* protected by lo->mutex */
struct lo_map ino_map; /* protected by lo->mutex */
struct lo_map dirp_map; /* protected by lo->mutex */
};
static const struct fuse_opt lo_opts[] = {
@ -252,6 +236,20 @@ static void lo_map_remove(struct lo_map *map, size_t key)
map->freelist = key;
}
/* Assumes lo->mutex is held */
static ssize_t lo_add_dirp_mapping(fuse_req_t req, struct lo_dirp *dirp)
{
struct lo_map_elem *elem;
elem = lo_map_alloc_elem(&lo_data(req)->dirp_map);
if (!elem) {
return -1;
}
elem->dirp = dirp;
return elem - lo_data(req)->dirp_map.elems;
}
/* Assumes lo->mutex is held */
static ssize_t lo_add_inode_mapping(fuse_req_t req, struct lo_inode *inode)
{
@ -861,9 +859,19 @@ struct lo_dirp {
off_t offset;
};
static struct lo_dirp *lo_dirp(struct fuse_file_info *fi)
static struct lo_dirp *lo_dirp(fuse_req_t req, struct fuse_file_info *fi)
{
return (struct lo_dirp *)(uintptr_t)fi->fh;
struct lo_data *lo = lo_data(req);
struct lo_map_elem *elem;
pthread_mutex_lock(&lo->mutex);
elem = lo_map_get(&lo->dirp_map, fi->fh);
pthread_mutex_unlock(&lo->mutex);
if (!elem) {
return NULL;
}
return elem->dirp;
}
static void lo_opendir(fuse_req_t req, fuse_ino_t ino,
@ -873,6 +881,7 @@ static void lo_opendir(fuse_req_t req, fuse_ino_t ino,
struct lo_data *lo = lo_data(req);
struct lo_dirp *d;
int fd;
ssize_t fh;
d = calloc(1, sizeof(struct lo_dirp));
if (d == NULL) {
@ -892,7 +901,14 @@ static void lo_opendir(fuse_req_t req, fuse_ino_t ino,
d->offset = 0;
d->entry = NULL;
fi->fh = (uintptr_t)d;
pthread_mutex_lock(&lo->mutex);
fh = lo_add_dirp_mapping(req, d);
pthread_mutex_unlock(&lo->mutex);
if (fh == -1) {
goto out_err;
}
fi->fh = fh;
if (lo->cache == CACHE_ALWAYS) {
fi->keep_cache = 1;
}
@ -903,6 +919,9 @@ out_errno:
error = errno;
out_err:
if (d) {
if (d->dp) {
closedir(d->dp);
}
if (fd != -1) {
close(fd);
}
@ -920,17 +939,21 @@ static int is_dot_or_dotdot(const char *name)
static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi, int plus)
{
struct lo_dirp *d = lo_dirp(fi);
char *buf;
struct lo_dirp *d;
char *buf = NULL;
char *p;
size_t rem = size;
int err;
int err = ENOMEM;
(void)ino;
d = lo_dirp(req, fi);
if (!d) {
goto error;
}
buf = calloc(1, size);
if (!buf) {
err = ENOMEM;
goto error;
}
p = buf;
@ -1028,8 +1051,21 @@ static void lo_readdirplus(fuse_req_t req, fuse_ino_t ino, size_t size,
static void lo_releasedir(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
{
struct lo_dirp *d = lo_dirp(fi);
struct lo_data *lo = lo_data(req);
struct lo_dirp *d;
(void)ino;
d = lo_dirp(req, fi);
if (!d) {
fuse_reply_err(req, EBADF);
return;
}
pthread_mutex_lock(&lo->mutex);
lo_map_remove(&lo->dirp_map, fi->fh);
pthread_mutex_unlock(&lo->mutex);
closedir(d->dp);
free(d);
fuse_reply_err(req, 0);
@ -1081,8 +1117,18 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
struct fuse_file_info *fi)
{
int res;
int fd = dirfd(lo_dirp(fi)->dp);
struct lo_dirp *d;
int fd;
(void)ino;
d = lo_dirp(req, fi);
if (!d) {
fuse_reply_err(req, EBADF);
return;
}
fd = dirfd(d->dp);
if (datasync) {
res = fdatasync(fd);
} else {
@ -1614,6 +1660,8 @@ int main(int argc, char *argv[])
root_elem = lo_map_reserve(&lo.ino_map, lo.root.fuse_ino);
root_elem->inode = &lo.root;
lo_map_init(&lo.dirp_map);
if (fuse_parse_cmdline(&args, &opts) != 0) {
return 1;
}
@ -1710,6 +1758,7 @@ err_out2:
err_out1:
fuse_opt_free_args(&args);
lo_map_destroy(&lo.dirp_map);
lo_map_destroy(&lo.ino_map);
if (lo.root.fd >= 0) {