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fuse-overlayfs/main.c
Giuseppe Scrivano 616119093a
fuse-overlayfs: use renameat2(RENAME_WHITEOUT) when possible 
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
2018-07-13 00:03:34 +02:00

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/* fuse-overlayfs: Overlay Filesystem in Userspace
Copyright (C) 2018 Giuseppe Scrivano <giuseppe@scrivano.org>
Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define _GNU_SOURCE
#define FUSE_USE_VERSION 31
#define _FILE_OFFSET_BITS 64
#include <config.h>
#include <fuse_lowlevel.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
#include <limits.h>
#include <dirent.h>
#include <assert.h>
#include <errno.h>
#include <err.h>
#include <error.h>
#include <inttypes.h>
#include <fcntl.h>
#include <hash.h>
#include <sys/statvfs.h>
#include <sys/file.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <fts.h>
#include <sys/sysmacros.h>
#include <sys/xattr.h>
#include <linux/fs.h>
#ifndef RENAME_EXCHANGE
# define RENAME_EXCHANGE (1 << 1)
# define RENAME_NOREPLACE (1 << 2)
#endif
#define ATTR_TIMEOUT 1000000000.0
#define ENTRY_TIMEOUT 1000000000.0
#define REDIRECT_XATTR "user.fuseoverlayfs.redirect"
#define NODE_TO_INODE(x) ((fuse_ino_t) x)
#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 ovl_layer
{
struct ovl_layer *next;
char *path;
int fd;
bool low;
};
struct ovl_mapping
{
struct ovl_mapping *next;
unsigned int host;
unsigned int to;
unsigned int len;
};
struct ovl_node
{
struct ovl_node *parent;
Hash_table *children;
struct ovl_layer *layer;
char *path;
char *name;
int lookups;
ino_t ino;
int hidden_dirfd;
unsigned int present_lowerdir : 1;
unsigned int do_unlink : 1;
unsigned int do_rmdir : 1;
unsigned int hidden : 1;
unsigned int whiteout : 1;
};
struct ovl_data
{
struct fuse_session *se;
int debug;
char *uid_str;
char *gid_str;
struct ovl_mapping *uid_mappings;
struct ovl_mapping *gid_mappings;
char *lowerdir;
char *context;
char *upperdir;
char *workdir;
int workdir_fd;
struct ovl_layer *layers;
struct ovl_node *root;
};
static const struct fuse_opt ovl_opts[] = {
{"context=%s",
offsetof (struct ovl_data, context), 0},
{"lowerdir=%s",
offsetof (struct ovl_data, lowerdir), 0},
{"upperdir=%s",
offsetof (struct ovl_data, upperdir), 0},
{"workdir=%s",
offsetof (struct ovl_data, workdir), 0},
{"uidmapping=%s",
offsetof (struct ovl_data, uid_str), 0},
{"gidmapping=%s",
offsetof (struct ovl_data, gid_str), 0},
FUSE_OPT_END
};
static struct ovl_data *
ovl_data (fuse_req_t req)
{
return (struct ovl_data *) fuse_req_userdata (req);
}
static unsigned long
get_next_wd_counter ()
{
static unsigned long counter = 1;
return counter++;
}
static struct ovl_mapping *
read_mappings (const char *str)
{
char *buf = NULL, *saveptr = NULL, *it, *endptr;
struct ovl_mapping *tmp, *ret = NULL;
unsigned int a, b, c;
int state = 0;
buf = alloca (strlen (str) + 1);
strcpy (buf, str);
for (it = strtok_r (buf, ":", &saveptr); it; it = strtok_r (NULL, ":", &saveptr))
{
switch (state)
{
case 0:
a = strtol (it, &endptr, 10);
if (*endptr != 0)
error (EXIT_FAILURE, 0, "invalid mapping specified: %s", str);
state++;
break;
case 1:
b = strtol (it, &endptr, 10);
if (*endptr != 0)
error (EXIT_FAILURE, 0, "invalid mapping specified: %s", str);
state++;
break;
case 2:
c = strtol (it, &endptr, 10);
if (*endptr != 0)
error (EXIT_FAILURE, 0, "invalid mapping specified: %s", str);
state = 0;
tmp = malloc (sizeof (*tmp));
if (tmp == NULL)
return NULL;
tmp->next = ret;
tmp->host = a;
tmp->to = b;
tmp->len = c;
ret = tmp;
break;
}
}
if (state != 0)
error (EXIT_FAILURE, 0, "invalid mapping specified: %s", str);
return ret;
}
static void
free_mapping (struct ovl_mapping *it)
{
struct ovl_mapping *next = NULL;
for (; it; it = next)
{
next = it->next;
free (it);
}
}
/* Useful in a gdb session. */
void
dump_directory (struct ovl_node *node)
{
struct ovl_node *it;
if (node->children == NULL)
return;
for (it = hash_get_first (node->children); it; it = hash_get_next (node->children, it))
printf ("ENTRY: %s (%s)\n", it->name, it->path);
}
static bool
ovl_debug (fuse_req_t req)
{
return ovl_data (req)->debug != 0;
}
static void
ovl_init (void *userdata, struct fuse_conn_info *conn)
{
conn->want |= FUSE_CAP_DONT_MASK | FUSE_CAP_SPLICE_READ | FUSE_CAP_SPLICE_MOVE;
conn->want &= ~FUSE_CAP_PARALLEL_DIROPS;
}
static struct ovl_layer *
get_upper_layer (struct ovl_data *lo)
{
return lo->layers;
}
static inline bool
node_dirp (struct ovl_node *n)
{
return n->children != NULL;
}
static int
node_dirfd (struct ovl_node *n)
{
if (n->hidden)
return n->hidden_dirfd;
return n->layer->fd;
}
static bool
has_prefix (const char *str, const char *pref)
{
while (1)
{
if (*pref == '\0')
return true;
if (*str == '\0')
return false;
if (*pref != *str)
return false;
str++;
pref++;
}
return false;
}
static int
create_whiteout (struct ovl_data *lo, struct ovl_node *parent, const char *name)
{
char whiteout_path[PATH_MAX + 10];
int fd = -1;
static bool can_mknod = true;
if (can_mknod)
{
int ret;
sprintf (whiteout_path, "%s/%s", parent->path, name);
ret = mknodat (get_upper_layer (lo)->fd, whiteout_path, S_IFCHR|0700, makedev (0, 0));
if (ret == 0)
return 0;
if (errno != EPERM)
return -1;
/* if it fails with EPERM then do not attempt mknod again. */
can_mknod = false;
}
sprintf (whiteout_path, "%s/.wh.%s", parent->path, name);
fd = TEMP_FAILURE_RETRY (openat (get_upper_layer (lo)->fd, whiteout_path, O_CREAT|O_WRONLY, 0700));
if (fd < 0 && errno != EEXIST)
return -1;
close (fd);
return 0;
}
static int
delete_whiteout (struct ovl_data *lo, int dirfd, struct ovl_node *parent, const char *name)
{
char whiteout_path[PATH_MAX + 10];
if (dirfd >= 0)
{
sprintf (whiteout_path, ".wh.%s", name);
if (unlinkat (dirfd, whiteout_path, 0) < 0 && errno != ENOENT)
return -1;
}
else
{
sprintf (whiteout_path, "%s/.wh.%s", parent->path, name);
if (unlinkat (get_upper_layer (lo)->fd, whiteout_path, 0) < 0 && errno != ENOENT)
return -1;
}
return 0;
}
static int
hide_node (struct ovl_data *lo, struct ovl_node *node, bool unlink_src)
{
char dest[PATH_MAX];
char *newpath;
asprintf (&newpath, "%lu", get_next_wd_counter ());
if (newpath == NULL)
{
unlink (dest);
return -1;
}
assert (node->layer == get_upper_layer (lo));
/* Might be leftover from a previous run. */
unlinkat (lo->workdir_fd, newpath, 0);
if (! unlink_src)
{
if (linkat (node_dirfd (node), node->path, lo->workdir_fd, newpath, 0) < 0)
{
free (newpath);
return -1;
}
}
else
{
/* If the atomic rename+mknod failed, then fallback into doing it in two steps. */
if (syscall (SYS_renameat2, node_dirfd (node), node->path, lo->workdir_fd,
newpath, RENAME_WHITEOUT) < 0)
{
if (renameat (node_dirfd (node), node->path, lo->workdir_fd, newpath) < 0)
{
free (newpath);
return -1;
}
if (node->parent)
{
if (create_whiteout (lo, node->parent, node->name) < 0)
return -1;
}
}
}
node->hidden_dirfd = lo->workdir_fd;
free (node->path);
node->path = newpath;
node->hidden = 1;
node->parent = NULL;
if (node_dirp (node))
node->do_rmdir = 1;
else
node->do_unlink = 1;
return 0;
}
static unsigned int
find_mapping (unsigned int id, struct ovl_mapping *mapping, bool direct)
{
if (mapping == NULL)
return id;
for (; mapping; mapping = mapping->next)
{
if (direct)
{
if (id >= mapping->host && id < mapping->host + mapping->len)
return mapping->to + (id - mapping->host);
}
else
{
if (id >= mapping->to && id < mapping->to + mapping->len)
return mapping->host + (id - mapping->to);
}
}
return 65534;
}
static uid_t
get_uid (struct ovl_data *data, uid_t id)
{
return find_mapping (id, data->uid_mappings, false);
}
static uid_t
get_gid (struct ovl_data *data, gid_t id)
{
return find_mapping (id, data->gid_mappings, false);
}
static int
rpl_stat (fuse_req_t req, struct ovl_node *node, struct stat *st)
{
int ret;
struct ovl_data *data = ovl_data (req);
ret = TEMP_FAILURE_RETRY (fstatat (node_dirfd (node), node->path, st, AT_SYMLINK_NOFOLLOW));
if (ret < 0)
return ret;
st->st_uid = find_mapping (st->st_uid, data->uid_mappings, true);
st->st_gid = find_mapping (st->st_gid, data->gid_mappings, true);
st->st_ino = node->ino;
if (ret == 0 && node_dirp (node))
{
struct ovl_node *it;
st->st_nlink = 2;
for (it = hash_get_first (node->children); it; it = hash_get_next (node->children, it))
{
if (node_dirp (it))
st->st_nlink++;
}
}
return ret;
}
static void
node_mark_all_free (void *p)
{
struct ovl_node *it, *n = (struct ovl_node *) p;
n->lookups = 0;
if (n->children)
{
for (it = hash_get_first (n->children); it; it = hash_get_next (n->children, it))
node_mark_all_free (it);
}
}
static void
node_free (void *p)
{
struct ovl_node *n = (struct ovl_node *) p;
if (n->parent)
{
if (hash_lookup (n->parent->children, n) == n)
hash_delete (n->parent->children, n);
n->parent = NULL;
}
if (n->lookups > 0)
return;
if (n->children)
{
struct ovl_node *it;
for (it = hash_get_first (n->children); it; it = hash_get_next (n->children, it))
it->parent = NULL;
hash_free (n->children);
n->children = NULL;
}
if (n->do_unlink)
unlinkat (n->hidden_dirfd, n->path, 0);
if (n->do_rmdir)
unlinkat (n->hidden_dirfd, n->path, AT_REMOVEDIR);
free (n->name);
free (n->path);
free (n);
return;
}
static void
do_forget (fuse_ino_t ino, uint64_t nlookup)
{
struct ovl_node *n;
if (ino == FUSE_ROOT_ID)
return;
n = (struct ovl_node *) ino;
n->lookups -= nlookup;
if (n->lookups <= 0)
node_free (n);
}
static void
ovl_forget (fuse_req_t req, fuse_ino_t ino, uint64_t nlookup)
{
if (ovl_debug (req))
fprintf (stderr, "ovl_forget(ino=%" PRIu64 ", nlookup=%lu)\n",
ino, nlookup);
do_forget (ino, nlookup);
fuse_reply_none (req);
}
static size_t
node_hasher (const void *p, size_t s)
{
struct ovl_node *n = (struct ovl_node *) p;
return hash_string (n->name, s);
}
static bool
node_compare (const void *n1, const void *n2)
{
struct ovl_node *node1 = (struct ovl_node *) n1;
struct ovl_node *node2 = (struct ovl_node *) n2;
return strcmp (node1->name, node2->name) == 0 ? true : false;
}
static struct ovl_node *
make_whiteout_node (const char *name)
{
struct ovl_node *ret = calloc (1, sizeof (*ret));
if (ret == NULL)
{
errno = ENOMEM;
return NULL;
}
ret->name = strdup (name);
if (ret->name == NULL)
{
free (ret);
errno = ENOMEM;
return NULL;
}
ret->whiteout = 1;
return ret;
}
static struct ovl_node *
make_ovl_node (const char *path, struct ovl_layer *layer, const char *name, ino_t ino, bool dir_p)
{
struct ovl_node *ret = malloc (sizeof (*ret));
if (ret == NULL)
{
errno = ENOMEM;
return NULL;
}
ret->parent = NULL;
ret->lookups = 0;
ret->do_unlink = 0;
ret->hidden = 0;
ret->do_rmdir = 0;
ret->whiteout = 0;
ret->layer = layer;
ret->ino = ino;
ret->present_lowerdir = 0;
ret->name = strdup (name);
ret->hidden_dirfd = 0;
if (ret->name == NULL)
{
free (ret);
errno = ENOMEM;
return NULL;
}
if (has_prefix (path, "./") && path[2])
path += 2;
ret->path = strdup (path);
if (ret->path == NULL)
{
free (ret->name);
free (ret);
errno = ENOMEM;
return NULL;
}
if (!dir_p)
ret->children = NULL;
else
{
ret->children = hash_initialize (10, NULL, node_hasher, node_compare, node_free);
if (ret->children == NULL)
{
free (ret->path);
free (ret->name);
free (ret);
errno = ENOMEM;
return NULL;
}
}
if (ret->ino == 0)
{
struct stat st;
struct ovl_layer *it;
char path[PATH_MAX];
strcpy (path, ret->path);
for (it = layer; it; it = it->next)
{
ssize_t s;
int fd = TEMP_FAILURE_RETRY (openat (it->fd, path, O_RDONLY));
if (fd < 0)
continue;
if (fstat (fd, &st) == 0)
ret->ino = st.st_ino;
/* If a redirect is specified, use it for the next layer lookup. */
s = fgetxattr (fd, REDIRECT_XATTR, path, sizeof (path) - 1);
if (s > 0)
path[s] = '\0';
close (fd);
}
}
return ret;
}
static struct ovl_node *
insert_node (struct ovl_node *parent, struct ovl_node *item, bool replace)
{
struct ovl_node *old = NULL, *prev_parent = item->parent;
int ret;
if (prev_parent)
{
if (hash_lookup (prev_parent->children, item) == item)
hash_delete (prev_parent->children, item);
}
if (replace)
{
old = hash_delete (parent->children, item);
if (old)
node_free (old);
}
ret = hash_insert_if_absent (parent->children, item, (const void **) &old);
if (ret < 0)
{
node_free (item);
errno = ENOMEM;
return NULL;
}
if (ret == 0)
{
node_free (item);
return old;
}
item->parent = parent;
return item;
}
static const char *
get_whiteout_name (const char *name, struct stat *st)
{
if (has_prefix (name, ".wh."))
return name + 4;
if ((st->st_mode & S_IFMT) == S_IFCHR
&& major (st->st_rdev) == 0
&& minor (st->st_rdev) == 0)
return name;
return NULL;
}
static struct ovl_node *
load_dir (struct ovl_data *lo, struct ovl_node *n, struct ovl_layer *layer, char *path, char *name)
{
DIR *dp;
struct dirent *dent;
struct stat st;
struct ovl_layer *it;
if (!n)
{
n = make_ovl_node (path, layer, name, 0, true);
if (n == NULL)
return NULL;
}
for (it = lo->layers; it; it = it->next)
{
int fd = TEMP_FAILURE_RETRY (openat (it->fd, path, O_DIRECTORY));
if (fd < 0)
continue;
dp = fdopendir (fd);
if (dp == NULL)
{
close (fd);
continue;
}
while (((dent = readdir (dp)) != NULL))
{
struct ovl_node key;
const char *wh;
char path[PATH_MAX + 1];
struct ovl_node *child = NULL;
key.name = dent->d_name;
if ((strcmp (dent->d_name, ".") == 0) || strcmp (dent->d_name, "..") == 0)
continue;
if (TEMP_FAILURE_RETRY (fstatat (fd, dent->d_name, &st, AT_SYMLINK_NOFOLLOW)) < 0)
{
closedir (dp);
return NULL;
}
child = hash_lookup (n->children, &key);
if (child)
continue;
wh = get_whiteout_name (dent->d_name, &st);
if (wh)
{
child = make_whiteout_node (wh);
if (child == NULL)
{
errno = ENOMEM;
closedir (dp);
return NULL;
}
}
else
{
bool dirp = st.st_mode & S_IFDIR;
sprintf (path, "%s/%s", n->path, dent->d_name);
child = make_ovl_node (path, it, dent->d_name, 0, dirp);
if (child == NULL)
{
errno = ENOMEM;
closedir (dp);
return NULL;
}
}
if (insert_node (n, child, false) == NULL)
{
errno = ENOMEM;
return NULL;
}
}
closedir (dp);
}
return n;
}
static void
free_layers (struct ovl_layer *layers)
{
if (layers == NULL)
return;
free_layers (layers->next);
free (layers->path);
if (layers->fd >= 0)
close (layers->fd);
free (layers);
}
static struct ovl_layer *
read_dirs (char *path, bool low, struct ovl_layer *layers)
{
char *buf = NULL, *saveptr = NULL, *it;
if (path == NULL)
return NULL;
buf = strdup (path);
if (buf == NULL)
return NULL;
for (it = strtok_r (path, ":", &saveptr); it; it = strtok_r (NULL, ":", &saveptr))
{
char full_path[PATH_MAX + 1];
struct ovl_layer *l = NULL;
if (realpath (it, full_path) < 0)
return NULL;
l = malloc (sizeof (*l));
if (l == NULL)
{
free_layers (layers);
return NULL;
}
l->path = strdup (full_path);
if (l->path == NULL)
{
free (l);
free_layers (layers);
return NULL;
}
l->fd = open (l->path, O_DIRECTORY);
if (l->fd < 0)
{
free (l->path);
free (l);
free_layers (layers);
return NULL;
}
l->low = low;
l->next = layers;
layers = l;
}
free (buf);
return layers;
}
static struct ovl_node *
do_lookup_file (struct ovl_data *lo, fuse_ino_t parent, const char *name)
{
struct ovl_node key;
struct ovl_node *node, *pnode;
if (parent == FUSE_ROOT_ID)
pnode = lo->root;
else
pnode = (struct ovl_node *) parent;
if (name == NULL)
return pnode;
if (has_prefix (name, ".wh."))
{
errno = EINVAL;
return NULL;
}
key.name = (char *) name;
node = hash_lookup (pnode->children, &key);
if (node == NULL)
{
int ret;
char path[PATH_MAX];
struct ovl_layer *it;
struct stat st;
for (it = lo->layers; it; it = it->next)
{
const char *wh_name;
sprintf (path, "%s/%s", pnode->path, name);
ret = TEMP_FAILURE_RETRY (fstatat (it->fd, path, &st, AT_SYMLINK_NOFOLLOW));
if (ret < 0)
{
int saved_errno = errno;
if (errno == ENOENT)
continue;
if (node)
node_free (node);
errno = saved_errno;
return NULL;
}
wh_name = get_whiteout_name (name, &st);
if (wh_name)
node = make_whiteout_node (wh_name);
else
node = make_ovl_node (path, it, name, 0, st.st_mode & S_IFDIR);
if (node == NULL)
{
errno = ENOMEM;
return NULL;
}
if (insert_node (pnode, node, false) == NULL)
{
node_free (node);
errno = ENOMEM;
return NULL;
}
}
}
if (node == NULL || node->whiteout)
{
errno = ENOENT;
return NULL;
}
return node;
}
static void
ovl_lookup (fuse_req_t req, fuse_ino_t parent, const char *name)
{
struct fuse_entry_param e;
int err = 0;
struct ovl_data *lo = ovl_data (req);
struct ovl_node *node;
if (ovl_debug (req))
fprintf (stderr, "ovl_lookup(parent=%" PRIu64 ", name=%s)\n",
parent, name);
memset (&e, 0, sizeof (e));
node = do_lookup_file (lo, parent, name);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
err = rpl_stat (req, node, &e.attr);
if (err)
{
fuse_reply_err (req, errno);
return;
}
e.ino = NODE_TO_INODE (node);
node->lookups++;
e.attr_timeout = ATTR_TIMEOUT;
e.entry_timeout = ENTRY_TIMEOUT;
fuse_reply_entry (req, &e);
}
struct ovl_dirp
{
struct ovl_data *lo;
struct ovl_node **tbl;
size_t tbl_size;
size_t offset;
};
static struct ovl_dirp *
ovl_dirp (struct fuse_file_info *fi)
{
return (struct ovl_dirp *) (uintptr_t) fi->fh;
}
static void
ovl_opendir (fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
{
size_t counter = 0;
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
struct ovl_node *it;
struct ovl_dirp *d = calloc (1, sizeof (struct ovl_dirp));
if (d == NULL)
{
errno = ENOENT;
goto out_errno;
}
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
errno = ENOENT;
goto out_errno;
}
if (! node_dirp (node))
{
errno = ENOTDIR;
goto out_errno;
}
node = load_dir (lo, node, node->layer, node->path, node->name);
if (node == NULL)
goto out_errno;
d->offset = 0;
d->tbl_size = hash_get_n_entries (node->children) + 2;
d->tbl = malloc (sizeof (struct ovl_node *) * d->tbl_size);
if (d->tbl == NULL)
{
errno = ENOMEM;
goto out_errno;
}
d->tbl[counter++] = node;
d->tbl[counter++] = node->parent;
for (it = hash_get_first (node->children); it; it = hash_get_next (node->children, it))
{
it->lookups++;
d->tbl[counter++] = it;
}
fi->fh = (uintptr_t) d;
fuse_reply_open (req, fi);
return;
out_errno:
if (d)
{
if (d->tbl)
free (d->tbl);
free (d);
}
fuse_reply_err (req, errno);
}
static void
ovl_do_readdir (fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi, int plus)
{
struct ovl_dirp *d = ovl_dirp (fi);
size_t remaining = size;
char *p, *buffer = calloc (size, 1);
if (buffer == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
p = buffer;
for (;remaining > 0 && offset < d->tbl_size; offset++)
{
int ret;
size_t entsize;
struct stat st;
const char *name;
struct ovl_node *node = d->tbl[offset];
if (node == NULL || node->whiteout)
continue;
ret = rpl_stat (req, node, &st);
if (ret < 0)
{
fuse_reply_err (req, errno);
goto exit;
}
if (offset == 0)
name = ".";
else if (offset == 1)
name = "..";
else
name = node->name;
if (!plus)
entsize = fuse_add_direntry (req, p, remaining, name, &st, offset + 1);
else
{
struct fuse_entry_param e;
memset (&e, 0, sizeof (e));
e.attr_timeout = ATTR_TIMEOUT;
e.entry_timeout = ENTRY_TIMEOUT;
e.ino = NODE_TO_INODE (node);
memcpy (&e.attr, &st, sizeof (st));
entsize = fuse_add_direntry_plus (req, p, remaining, name, &e, offset + 1);
if (entsize <= remaining)
{
/* First two entries are . and .. */
if (offset >= 2)
node->lookups++;
}
}
if (entsize > remaining)
break;
p += entsize;
remaining -= entsize;
}
fuse_reply_buf (req, buffer, size - remaining);
exit:
free (buffer);
}
static void
ovl_readdir (fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi)
{
ovl_do_readdir (req, ino, size, offset, fi, 0);
}
static void
ovl_readdirplus (fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi)
{
ovl_do_readdir (req, ino, size, offset, fi, 1);
}
static void
ovl_releasedir (fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
{
size_t s;
struct ovl_dirp *d = ovl_dirp (fi);
for (s = 2; s < d->tbl_size; s++)
{
struct ovl_node *n = d->tbl[s];
do_forget (NODE_TO_INODE (n), 1);
}
free (d->tbl);
free (d);
fuse_reply_err (req, 0);
}
static void
ovl_listxattr (fuse_req_t req, fuse_ino_t ino, size_t size)
{
ssize_t len;
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
char *buf = NULL;
int fd;
if (ovl_debug (req))
fprintf (stderr, "ovl_listxattr(ino=%" PRIu64 ", size=%zu)\n", ino, size);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
if (size > 0)
{
buf = malloc (size);
if (buf == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
}
fd = TEMP_FAILURE_RETRY (openat (node_dirfd (node), node->path, O_RDONLY));
if (fd < 0)
{
free (buf);
fuse_reply_err (req, errno);
return;
}
len = flistxattr (fd, buf, size);
if (len < 0)
fuse_reply_err (req, errno);
else if (size == 0)
fuse_reply_xattr (req, len);
else if (len <= size)
fuse_reply_buf (req, buf, len);
free (buf);
close (fd);
}
static void
ovl_getxattr (fuse_req_t req, fuse_ino_t ino, const char *name, size_t size)
{
ssize_t len;
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
char *buf = NULL;
int fd;
if (ovl_debug (req))
fprintf (stderr, "ovl_getxattr(ino=%" PRIu64 ", name=%s, size=%zu)\n", ino, name, size);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
if (size > 0)
{
buf = malloc (size);
if (buf == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
}
fd = TEMP_FAILURE_RETRY (openat (node_dirfd (node), node->path, O_RDONLY));
if (fd < 0)
{
free (buf);
fuse_reply_err (req, errno);
return;
}
len = fgetxattr (fd, name, buf, size);
if (len < 0)
fuse_reply_err (req, errno);
else if (size == 0)
fuse_reply_xattr (req, len);
else if (len <= size)
fuse_reply_buf (req, buf, len);
free (buf);
close (fd);
}
static void
ovl_access (fuse_req_t req, fuse_ino_t ino, int mask)
{
int ret;
struct ovl_data *lo = ovl_data (req);
struct ovl_node *n = do_lookup_file (lo, ino, NULL);
if (ovl_debug (req))
fprintf (stderr, "ovl_access(ino=%" PRIu64 ", mask=%d)\n",
ino, mask);
ret = faccessat (node_dirfd (n), n->path, mask, AT_SYMLINK_NOFOLLOW);
fuse_reply_err (req, ret < 0 ? errno : 0);
}
static int
copy_xattr (int sfd, int dfd, char *buf, size_t buf_size)
{
size_t xattr_len;
xattr_len = flistxattr (sfd, buf, buf_size / 2);
if (xattr_len > 0)
{
char *it;
char *xattr_buf = buf + buf_size / 2;
for (it = buf; it - buf < xattr_len; it += strlen (it) + 1)
{
ssize_t s = fgetxattr (sfd, it, xattr_buf, buf_size / 2);
if (s < 0)
return -1;
if (fsetxattr (dfd, it, xattr_buf, s, 0) < 0)
return -1;
}
}
return 0;
}
static int
create_directory (struct ovl_data *lo, struct ovl_node *src)
{
int ret;
struct stat st;
int sfd = -1, dfd = -1;
char *buf = NULL;
char wd_tmp_file_name[32];
struct timespec times[2];
if (src == NULL)
return 0;
if (src->layer == get_upper_layer (lo))
return 0;
sprintf (wd_tmp_file_name, "%lu", get_next_wd_counter ());
ret = sfd = TEMP_FAILURE_RETRY (openat (node_dirfd (src), src->path, O_RDONLY));
if (ret < 0)
goto out;
ret = TEMP_FAILURE_RETRY (fstat (sfd, &st));
if (ret < 0)
return ret;
ret = mkdirat (lo->workdir_fd, wd_tmp_file_name, st.st_mode);
if (ret < 0)
goto out;
ret = dfd = TEMP_FAILURE_RETRY (openat (lo->workdir_fd, wd_tmp_file_name, O_RDONLY));
if (ret < 0)
goto out;
ret = fchown (dfd, st.st_uid, st.st_gid);
if (ret < 0)
goto out;
times[0] = st.st_atim;
times[1] = st.st_mtim;
ret = futimens (dfd, times);
if (ret < 0)
goto out;
if (ret == 0)
{
const size_t buf_size = 1 << 20;
char *buf = malloc (buf_size);
if (buf == NULL)
{
ret = -1;
goto out;
}
ret = copy_xattr (sfd, dfd, buf, buf_size);
if (ret < 0)
goto out;
}
ret = renameat (lo->workdir_fd, wd_tmp_file_name, get_upper_layer (lo)->fd, src->path);
if (ret < 0)
{
if (errno == ENOENT && src->parent)
{
ret = create_directory (lo, src->parent);
if (ret != 0)
goto out;
}
ret = renameat (lo->workdir_fd, wd_tmp_file_name, get_upper_layer (lo)->fd, src->path);
}
out:
if (sfd >= 0)
close (sfd);
if (dfd >= 0)
close (dfd);
if (buf)
free (buf);
if (ret < 0)
unlinkat (lo->workdir_fd, wd_tmp_file_name, AT_REMOVEDIR);
else
{
src->layer = get_upper_layer (lo);
if (src->parent)
delete_whiteout (lo, -1, src->parent, src->name);
}
return ret;
}
static int
copyup (struct ovl_data *lo, struct ovl_node *node)
{
int saved_errno;
int ret = -1;
int dfd = -1, sfd = -1;
struct stat st;
const size_t buf_size = 1 << 20;
char *buf = NULL;
struct timespec times[2];
char wd_tmp_file_name[32];
sprintf (wd_tmp_file_name, "%lu", get_next_wd_counter ());
ret = TEMP_FAILURE_RETRY (fstatat (node_dirfd (node), node->path, &st, AT_SYMLINK_NOFOLLOW));
if (ret < 0)
return ret;
if (node->parent)
{
ret = create_directory (lo, node->parent);
if (ret < 0)
return ret;
char whpath[PATH_MAX + 10];
sprintf (whpath, "%s/.wh.%s", node->parent->path, node->name);
if (unlinkat (get_upper_layer (lo)->fd, whpath, 0) < 0 && errno != ENOENT)
goto exit;
}
if ((st.st_mode & S_IFMT) == S_IFDIR)
{
ret = create_directory (lo, node);
if (ret < 0)
goto exit;
goto success;
}
if ((st.st_mode & S_IFMT) == S_IFLNK)
{
char p[PATH_MAX + 1];
ret = readlinkat (node_dirfd (node), node->path, p, sizeof (p) - 1);
if (ret < 0)
goto exit;
p[ret] = '\0';
ret = symlinkat (p, get_upper_layer (lo)->fd, node->path);
if (ret < 0)
goto exit;
goto success;
}
sfd = TEMP_FAILURE_RETRY (openat (node_dirfd (node), node->path, O_RDONLY));
if (sfd < 0)
goto exit;
dfd = TEMP_FAILURE_RETRY (openat (lo->workdir_fd, wd_tmp_file_name, O_CREAT|O_WRONLY, st.st_mode));
if (dfd < 0)
goto exit;
ret = fchown (dfd, st.st_uid, st.st_gid);
if (ret < 0)
goto exit;
buf = malloc (buf_size);
if (buf == NULL)
goto exit;
for (;;)
{
int written;
int nread;
nread = TEMP_FAILURE_RETRY (read (sfd, buf, buf_size));
if (nread < 0)
goto exit;
if (nread == 0)
break;
written = 0;
{
ret = TEMP_FAILURE_RETRY (write (dfd, buf + written, nread));
if (ret < 0)
goto exit;
written += ret;
nread -= ret;
}
while (nread);
}
times[0] = st.st_atim;
times[1] = st.st_mtim;
ret = futimens (dfd, times);
if (ret < 0)
goto exit;
ret = copy_xattr (sfd, dfd, buf, buf_size);
if (ret < 0)
goto exit;
/* Finally, move the file to its destination. */
ret = renameat (lo->workdir_fd, wd_tmp_file_name, get_upper_layer (lo)->fd, node->path);
if (ret < 0)
goto exit;
success:
ret = 0;
node->layer = get_upper_layer (lo);
exit:
saved_errno = errno;
free (buf);
if (sfd >= 0)
close (sfd);
if (dfd >= 0)
close (dfd);
if (ret < 0)
unlinkat (lo->workdir_fd, wd_tmp_file_name, 0);
errno = saved_errno;
return ret;
}
static struct ovl_node *
get_node_up (struct ovl_data *lo, struct ovl_node *node)
{
int ret;
if (node->layer == get_upper_layer (lo))
return node;
ret = copyup (lo, node);
if (ret < 0)
return NULL;
assert (node->layer == get_upper_layer (lo));
return node;
}
static size_t
count_dir_entries (struct ovl_node *node)
{
size_t c = 0;
struct ovl_node *it;
for (it = hash_get_first (node->children); it; it = hash_get_next (node->children, it))
{
if (it->whiteout)
continue;
if (strcmp (it->name, ".") == 0)
continue;
if (strcmp (it->name, "..") == 0)
continue;
c++;
}
return c;
}
static int
update_paths (struct ovl_node *node)
{
struct ovl_node *it;
if (node == NULL)
return 0;
if (node->parent)
{
free (node->path);
if (asprintf (&node->path, "%s/%s", node->parent->path, node->name) < 0)
{
node->path = NULL;
return -1;
}
}
if (node->children)
{
for (it = hash_get_first (node->children); it; it = hash_get_next (node->children, it))
{
if (update_paths (it) < 0)
return -1;
}
}
return 0;
}
static void
do_rm (fuse_req_t req, fuse_ino_t parent, const char *name, bool dirp)
{
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
struct ovl_node *pnode;
int ret = 0;
struct ovl_node key, *rm;
node = do_lookup_file (lo, parent, name);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
if (node->layer == get_upper_layer (lo))
{
node->hidden_dirfd = node->layer->fd;
if (! dirp)
node->do_unlink = 1;
else
{
DIR *dp;
size_t c = 0;
int fd;
fd = TEMP_FAILURE_RETRY (openat (get_upper_layer (lo)->fd, node->path, O_DIRECTORY ));
if (fd < 0)
{
fuse_reply_err (req, errno);
return;
}
if (node->children)
c = count_dir_entries (node);
if (c)
{
close (fd);
fuse_reply_err (req, ENOTEMPTY);
return;
}
if (fd >= 0)
{
dp = fdopendir (fd);
if (dp)
{
struct dirent *dent;
while (dp && ((dent = readdir (dp)) != NULL))
{
if (strcmp (dent->d_name, ".") == 0)
continue;
if (strcmp (dent->d_name, "..") == 0)
continue;
if (unlinkat (dirfd (dp), dent->d_name, 0) < 0)
unlinkat (dirfd (dp), dent->d_name, AT_REMOVEDIR);
}
closedir (dp);
}
}
node->do_rmdir = 1;
}
}
pnode = do_lookup_file (lo, parent, NULL);
if (pnode == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
pnode = get_node_up (lo, pnode);
if (pnode == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
/* If the node is still accessible then be sure we,
can write to it. Fix it to be done when a write is
really done, not now. */
node = get_node_up (lo, node);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
key.name = (char *) name;
rm = hash_delete (pnode->children, &key);
if (rm)
{
ret = hide_node (lo, rm, true);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
node_free (rm);
}
fuse_reply_err (req, ret);
}
static void
ovl_unlink (fuse_req_t req, fuse_ino_t parent, const char *name)
{
if (ovl_debug (req))
fprintf (stderr, "ovl_unlink(parent=%" PRIu64 ", name=%s)\n",
parent, name);
do_rm (req, parent, name, false);
}
static void
ovl_rmdir (fuse_req_t req, fuse_ino_t parent, const char *name)
{
if (ovl_debug (req))
fprintf (stderr, "ovl_rmdir(parent=%" PRIu64 ", name=%s)\n",
parent, name);
do_rm (req, parent, name, true);
}
static void
ovl_setxattr (fuse_req_t req, fuse_ino_t ino, const char *name,
const char *value, size_t size, int flags)
{
struct ovl_data *lo = ovl_data (req);
struct ovl_node *node;
if (ovl_debug (req))
fprintf (stderr, "ovl_setxattr(ino=%" PRIu64 "s, name=%s, value=%s, size=%zu, flags=%d)\n", ino, name,
value, size, flags);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
node = get_node_up (lo, node);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
if (setxattr (node->path, name, value, size, flags) < 0)
{
fuse_reply_err (req, errno);
return;
}
fuse_reply_err (req, 0);
}
static void
ovl_removexattr (fuse_req_t req, fuse_ino_t ino, const char *name)
{
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
if (ovl_debug (req))
fprintf (stderr, "ovl_removexattr(ino=%" PRIu64 "s, name=%s)\n", ino, name);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
node = get_node_up (lo, node);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
if (removexattr (node->path, name) < 0)
{
fuse_reply_err (req, errno);
return;
}
fuse_reply_err (req, 0);
}
static int
ovl_do_open (fuse_req_t req, fuse_ino_t parent, const char *name, int flags, mode_t mode)
{
struct ovl_data *lo = ovl_data (req);
struct ovl_node *n;
bool readonly = (flags & (O_APPEND | O_RDWR | O_WRONLY | O_CREAT | O_TRUNC)) == 0;
char path[PATH_MAX + 10];
int fd;
flags |= O_NOFOLLOW;
if (name && has_prefix (name, ".wh."))
{
errno = EINVAL;
return - 1;
}
n = do_lookup_file (lo, parent, name);
if (n && n->hidden)
{
n = NULL;
}
if (n && (flags & O_CREAT))
{
errno = EEXIST;
return -1;
}
if (!n)
{
struct ovl_node *p;
const struct fuse_ctx *ctx = fuse_req_ctx (req);
char wd_tmp_file_name[32];
if ((flags & O_CREAT) == 0)
{
errno = ENOENT;
return -1;
}
p = do_lookup_file (lo, parent, NULL);
if (p == NULL)
{
errno = ENOENT;
return -1;
}
p = get_node_up (lo, p);
if (p == NULL)
return -1;
if (delete_whiteout (lo, -1, p, name) < 0)
return -1;
sprintf (path, "%s/%s", p->path, name);
if (unlinkat (get_upper_layer (lo)->fd, path, 0) < 0 && errno != ENOENT)
return -1;
sprintf (wd_tmp_file_name, "%lu", get_next_wd_counter ());
fd = TEMP_FAILURE_RETRY (openat (lo->workdir_fd, wd_tmp_file_name, flags, mode));
if (fd < 0)
return -1;
if (fchown (fd, get_uid (lo, ctx->uid), get_gid (lo, ctx->gid)) < 0)
{
unlinkat (lo->workdir_fd, wd_tmp_file_name, 0);
return -1;
}
if (renameat (lo->workdir_fd, wd_tmp_file_name, get_upper_layer (lo)->fd, path) < 0)
{
unlinkat (lo->workdir_fd, wd_tmp_file_name, 0);
return -1;
}
n = make_ovl_node (path, get_upper_layer (lo), name, 0, false);
if (n == NULL)
{
errno = ENOMEM;
close (fd);
return -1;
}
n = insert_node (p, n, true);
if (n == NULL)
{
errno = ENOMEM;
close (fd);
return -1;
}
return fd;
}
/* readonly, we can use both lowerdir and upperdir. */
if (readonly)
{
return TEMP_FAILURE_RETRY (openat (node_dirfd (n), n->path, flags, mode));
}
else
{
n = get_node_up (lo, n);
if (n == NULL)
return -1;
return TEMP_FAILURE_RETRY (openat (node_dirfd (n), n->path, flags, mode));
}
}
static void
ovl_read (fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi)
{
struct fuse_bufvec buf = FUSE_BUFVEC_INIT (size);
if (ovl_debug (req))
fprintf (stderr, "ovl_read(ino=%" PRIu64 ", size=%zd, "
"off=%lu)\n", ino, size, (unsigned long) offset);
buf.buf[0].flags = FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK;
buf.buf[0].fd = fi->fh;
buf.buf[0].pos = offset;
fuse_reply_data (req, &buf, FUSE_BUF_SPLICE_MOVE);
}
static void
ovl_write_buf (fuse_req_t req, fuse_ino_t ino,
struct fuse_bufvec *in_buf, off_t off,
struct fuse_file_info *fi)
{
(void) ino;
ssize_t res;
struct fuse_bufvec out_buf = FUSE_BUFVEC_INIT (fuse_buf_size (in_buf));
out_buf.buf[0].flags = FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK;
out_buf.buf[0].fd = fi->fh;
out_buf.buf[0].pos = off;
if (ovl_debug (req))
fprintf (stderr, "ovl_write_buf(ino=%" PRIu64 ", size=%zd, off=%lu, fd=%d)\n",
ino, out_buf.buf[0].size, (unsigned long) off, (int) fi->fh);
errno = 0;
res = fuse_buf_copy (&out_buf, in_buf, 0);
if (res < 0)
fuse_reply_err (req, errno);
else
fuse_reply_write (req, (size_t) res);
}
static void
ovl_release (fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
{
(void) ino;
close (fi->fh);
fuse_reply_err (req, 0);
}
static int
do_getattr (fuse_req_t req, struct fuse_entry_param *e, struct ovl_node *node)
{
int err = 0;
memset (e, 0, sizeof (*e));
err = rpl_stat (req, node, &e->attr);
if (err < 0)
return err;
e->ino = (fuse_ino_t) node;
e->attr_timeout = ATTR_TIMEOUT;
e->entry_timeout = ENTRY_TIMEOUT;
return 0;
}
static void
ovl_create (fuse_req_t req, fuse_ino_t parent, const char *name,
mode_t mode, struct fuse_file_info *fi)
{
int fd;
struct fuse_entry_param e;
struct ovl_data *lo = ovl_data (req);
struct ovl_node *node;
if (ovl_debug (req))
fprintf (stderr, "ovl_create(parent=%" PRIu64 ", name=%s)\n",
parent, name);
fi->flags = fi->flags | O_CREAT;
fd = ovl_do_open (req, parent, name, fi->flags, mode);
if (fd < 0)
{
fuse_reply_err (req, errno);
return;
}
node = do_lookup_file (lo, parent, name);
if (node == NULL || do_getattr (req, &e, node) < 0)
{
close (fd);
fuse_reply_err (req, errno);
return;
}
fi->fh = fd;
node->lookups++;
fuse_reply_create (req, &e, fi);
}
static void
ovl_open (fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
{
int fd;
if (ovl_debug (req))
fprintf (stderr, "ovl_open(ino=%" PRIu64 "s)\n", ino);
fd = ovl_do_open (req, ino, NULL, fi->flags, 0700);
if (fd < 0)
{
fuse_reply_err (req, errno);
return;
}
fi->fh = fd;
fuse_reply_open (req, fi);
}
static void
ovl_getattr (fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
{
struct ovl_data *lo = ovl_data (req);
struct ovl_node *node;
struct fuse_entry_param e;
if (ovl_debug (req))
fprintf (stderr, "ovl_getattr(ino=%" PRIu64 "s)\n", ino);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
if (do_getattr (req, &e, node) < 0)
{
fuse_reply_err (req, errno);
return;
}
fuse_reply_attr (req, &e.attr, ENTRY_TIMEOUT);
}
static void
ovl_setattr (fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, struct fuse_file_info *fi)
{
struct ovl_data *lo = ovl_data (req);
struct ovl_node *node;
struct fuse_entry_param e;
struct stat old_st;
struct timespec times[2];
uid_t uid;
gid_t gid;
int dirfd;
if (ovl_debug (req))
fprintf (stderr, "ovl_setattr(ino=%" PRIu64 "s, to_set=%d)\n", ino, to_set);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
node = get_node_up (lo, node);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
dirfd = node_dirfd (node);
if (TEMP_FAILURE_RETRY (fstatat (dirfd, node->path, &old_st, AT_SYMLINK_NOFOLLOW)) < 0)
{
fuse_reply_err (req, errno);
return;
}
if (to_set & FUSE_SET_ATTR_CTIME)
{
fuse_reply_err (req, EPERM);
return;
}
times[0].tv_sec = UTIME_OMIT;
times[1].tv_sec = UTIME_OMIT;
if (to_set & FUSE_SET_ATTR_ATIME)
times[0] = attr->st_atim;
else if (to_set & FUSE_SET_ATTR_ATIME_NOW)
times[0].tv_sec = UTIME_NOW;
if (to_set & FUSE_SET_ATTR_MTIME)
times[1] = attr->st_mtim;
else if (to_set & FUSE_SET_ATTR_MTIME_NOW)
times[1].tv_sec = UTIME_NOW;
if (times[0].tv_sec != UTIME_OMIT || times[1].tv_sec != UTIME_OMIT)
{
if ((utimensat (dirfd, node->path, times, AT_SYMLINK_NOFOLLOW) < 0))
{
fuse_reply_err (req, errno);
return;
}
}
if ((to_set & FUSE_SET_ATTR_MODE) && fchmodat (dirfd, node->path, attr->st_mode, 0) < 0)
{
fuse_reply_err (req, errno);
return;
}
if ((to_set & FUSE_SET_ATTR_SIZE))
{
int fd = TEMP_FAILURE_RETRY (openat (dirfd, node->path, O_WRONLY));
if (fd < 0)
{
fuse_reply_err (req, errno);
return;
}
if (ftruncate (fd, attr->st_size) < 0)
{
close (fd);
fuse_reply_err (req, errno);
return;
}
close (fd);
}
uid = old_st.st_uid;
gid = old_st.st_gid;
if (to_set & FUSE_SET_ATTR_UID)
uid = get_uid (lo, attr->st_uid);
if (to_set & FUSE_SET_ATTR_GID)
gid = get_gid (lo, attr->st_gid);
if (uid != old_st.st_uid || gid != old_st.st_gid)
{
if (fchownat (dirfd, node->path, uid, gid, AT_SYMLINK_NOFOLLOW) < 0)
{
fuse_reply_err (req, errno);
return;
}
}
if (do_getattr (req, &e, node) < 0)
{
fuse_reply_err (req, errno);
return;
}
fuse_reply_attr (req, &e.attr, ENTRY_TIMEOUT);
}
static void
ovl_link (fuse_req_t req, fuse_ino_t ino, fuse_ino_t newparent, const char *newname)
{
struct ovl_data *lo = ovl_data (req);
struct ovl_node *node, *newparentnode, *destnode;
char path[PATH_MAX + 10];
int ret;
struct fuse_entry_param e;
if (ovl_debug (req))
fprintf (stderr, "ovl_link(ino=%" PRIu64 "s, newparent=%" PRIu64 "s, newname=%s)\n", ino, newparent, newname);
node = do_lookup_file (lo, newparent, newname);
if (node != NULL)
{
fuse_reply_err (req, EEXIST);
return;
}
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
node = get_node_up (lo, node);
if (node == NULL)
{
fuse_reply_err (req, errno);
return;
}
newparentnode = do_lookup_file (lo, newparent, NULL);
if (newparentnode == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
destnode = do_lookup_file (lo, newparent, newname);
if (destnode)
{
fuse_reply_err (req, EEXIST);
return;
}
newparentnode = get_node_up (lo, newparentnode);
if (newparentnode == NULL)
{
fuse_reply_err (req, errno);
return;
}
if (delete_whiteout (lo, -1, newparentnode, newname) < 0)
{
fuse_reply_err (req, errno);
return;
}
sprintf (path, "%s/%s", newparentnode->path, newname);
if (linkat (node_dirfd (newparentnode), node->path, node_dirfd (newparentnode), path, 0) < 0)
{
fuse_reply_err (req, errno);
return;
}
else
{
int dfd = TEMP_FAILURE_RETRY (openat (node_dirfd (newparentnode), path, O_WRONLY));
if (dfd >= 0)
{
bool set = false;
int sfd = TEMP_FAILURE_RETRY (openat (node_dirfd (node), node->path, O_RDONLY));
if (sfd >= 0)
{
char redirect_path[PATH_MAX + 10];
ssize_t s = fgetxattr (sfd, REDIRECT_XATTR, redirect_path, sizeof (redirect_path));
if (s > 0)
{
set = fsetxattr (dfd, REDIRECT_XATTR, redirect_path, s, 0) == 0;
}
close (sfd);
}
if (! set)
fsetxattr (dfd, REDIRECT_XATTR, node->path, strlen (node->path), 0);
close (dfd);
}
}
node = make_ovl_node (path, get_upper_layer (lo), newname, node->ino, false);
if (node == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
node = insert_node (newparentnode, node, true);
if (node == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
memset (&e, 0, sizeof (e));
ret = rpl_stat (req, node, &e.attr);
if (ret)
{
fuse_reply_err (req, errno);
return;
}
e.ino = NODE_TO_INODE (node);
node->lookups++;
e.attr_timeout = ATTR_TIMEOUT;
e.entry_timeout = ENTRY_TIMEOUT;
fuse_reply_entry (req, &e);
}
static void
ovl_symlink (fuse_req_t req, const char *link, fuse_ino_t parent, const char *name)
{
struct ovl_data *lo = ovl_data (req);
struct ovl_node *pnode, *node;
char path[PATH_MAX + 10];
int ret;
struct fuse_entry_param e;
if (ovl_debug (req))
fprintf (stderr, "ovl_symlink(link=%s, ino=%" PRIu64 "s, name=%s)\n", link, parent, name);
pnode = do_lookup_file (lo, parent, NULL);
if (pnode == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
pnode = get_node_up (lo, pnode);
if (pnode == NULL)
{
fuse_reply_err (req, errno);
return;
}
node = do_lookup_file (lo, parent, name);
if (node != NULL)
{
fuse_reply_err (req, EEXIST);
return;
}
if (delete_whiteout (lo, -1, pnode, name) < 0)
{
fuse_reply_err (req, errno);
return;
}
sprintf (path, "%s/%s", pnode->path, name);
ret = symlinkat (link, get_upper_layer (lo)->fd, path);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
node = make_ovl_node (path, get_upper_layer (lo), name, 0, false);
if (node == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
node = insert_node (pnode, node, true);
if (node == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
memset (&e, 0, sizeof (e));
ret = rpl_stat (req, node, &e.attr);
if (ret)
{
fuse_reply_err (req, errno);
return;
}
e.ino = NODE_TO_INODE (node);
node->lookups++;
e.attr_timeout = ATTR_TIMEOUT;
e.entry_timeout = ENTRY_TIMEOUT;
fuse_reply_entry (req, &e);
}
static void
ovl_flock (fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi, int op)
{
int ret, fd;
if (ovl_debug (req))
fprintf (stderr, "ovl_flock(ino=%" PRIu64 "s, op=%d)\n", ino, op);
fd = fi->fh;
ret = flock (fd, op);
fuse_reply_err (req, ret == 0 ? 0 : errno);
}
static void
ovl_rename (fuse_req_t req, fuse_ino_t parent, const char *name,
fuse_ino_t newparent, const char *newname,
unsigned int flags)
{
struct ovl_node *pnode, *node, *destnode, *destpnode;
struct ovl_data *lo = ovl_data (req);
int ret;
int saved_errno;
int srcfd = -1;
int destfd = -1;
struct ovl_node key, *rm = NULL;
if (ovl_debug (req))
fprintf (stderr, "ovl_rename(ino=%" PRIu64 "s, name=%s , ino=%" PRIu64 "s, name=%s)\n", parent, name, newparent, newname);
node = do_lookup_file (lo, parent, name);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
if (node_dirp (node) && node->present_lowerdir)
{
fuse_reply_err (req, EXDEV);
return;
}
pnode = node->parent;
destpnode = do_lookup_file (lo, newparent, NULL);
destnode = NULL;
pnode = get_node_up (lo, pnode);
if (pnode == NULL)
goto error;
ret = TEMP_FAILURE_RETRY (openat (node_dirfd (pnode), pnode->path, O_DIRECTORY));
if (ret < 0)
goto error;
srcfd = ret;
destpnode = get_node_up (lo, destpnode);
if (destpnode == NULL)
goto error;
ret = TEMP_FAILURE_RETRY (openat (node_dirfd (destpnode), destpnode->path, O_DIRECTORY));
if (ret < 0)
goto error;
destfd = ret;
destnode = do_lookup_file (lo, newparent, newname);
node = get_node_up (lo, node);
if (node == NULL)
goto error;
if (flags & RENAME_EXCHANGE)
{
if (destnode == NULL)
{
errno = ENOENT;
goto error;
}
destnode = get_node_up (lo, destnode);
if (destnode == NULL)
goto error;
}
else
{
key.name = (char *) newname;
if (flags & RENAME_NOREPLACE)
{
rm = hash_lookup (destpnode->children, &key);
if (rm)
{
errno = EEXIST;
goto error;
}
}
if (destnode != NULL && node_dirp (destnode))
{
errno = EISDIR;
goto error;
}
rm = hash_lookup (destpnode->children, &key);
if (rm)
{
if (rm->ino == node->ino)
{
fuse_reply_err (req, 0);
return;
}
hash_delete (destpnode->children, rm);
if (rm->lookups > 0)
node_free (rm);
else
{
node_free (rm);
rm = NULL;
}
if (rm)
{
/* If the node is still accessible then be sure we
can write to it. Fix it to be done when a write is
really done, not now. */
rm = get_node_up (lo, rm);
if (rm == NULL)
{
fuse_reply_err (req, errno);
return;
}
if (hide_node (lo, rm, false) < 0)
goto error;
}
}
}
if (flags & RENAME_EXCHANGE)
{
struct ovl_node *rm1, *rm2;
char *tmp;
ret = syscall (SYS_renameat2, srcfd, name, destfd, newname, flags);
if (ret < 0)
goto error;
rm1 = hash_delete (destpnode->children, destnode);
rm2 = hash_delete (pnode->children, node);
tmp = node->path;
node->path = destnode->path;
destnode->path = tmp;
tmp = node->name;
node->name = destnode->name;
destnode->name = tmp;
node = insert_node (destpnode, node, true);
if (node == NULL)
{
node_free (rm1);
node_free (rm2);
goto error;
}
destnode = insert_node (pnode, destnode, true);
if (destnode == NULL)
{
node_free (rm1);
node_free (rm2);
goto error;
}
if ((update_paths (node) < 0) || (update_paths (destnode) < 0))
goto error;
}
else
{
/* Try to create the whiteout atomically, if it fails do the
rename+mknod separately. */
ret = syscall (SYS_renameat2, srcfd, name, destfd,
newname, flags|RENAME_WHITEOUT);
if (ret < 0)
{
ret = syscall (SYS_renameat2, srcfd, name, destfd, newname, flags);
if (ret < 0)
goto error;
if (create_whiteout (lo, pnode, name) < 0)
goto error;
}
hash_delete (pnode->children, node);
free (node->name);
node->name = strdup (newname);
if (node->name == NULL)
goto error;
node = insert_node (destpnode, node, true);
if (node == NULL)
goto error;
if (update_paths (node) < 0)
goto error;
}
if (delete_whiteout (lo, destfd, NULL, newname) < 0)
goto error;
error:
saved_errno = errno;
if (srcfd >= 0)
close (srcfd);
if (destfd >= 0)
close (destfd);
errno = saved_errno;
fuse_reply_err (req, ret == 0 ? 0 : errno);
}
static void
ovl_statfs (fuse_req_t req, fuse_ino_t ino)
{
int ret;
struct statvfs sfs;
struct ovl_data *lo = ovl_data (req);
if (ovl_debug (req))
fprintf (stderr, "ovl_statfs(ino=%" PRIu64 "s)\n", ino);
ret = statvfs (lo->upperdir, &sfs);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
fuse_reply_statfs (req, &sfs);
}
static void
ovl_readlink (fuse_req_t req, fuse_ino_t ino)
{
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
int ret = 0;
char buf[PATH_MAX + 1];
if (ovl_debug (req))
fprintf (stderr, "ovl_readlink(ino=%" PRIu64 "s)\n", ino);
node = do_lookup_file (lo, ino, NULL);
if (node == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
ret = readlinkat (node_dirfd (node), node->path, buf, sizeof (buf));
if (ret == -1)
{
fuse_reply_err (req, errno);
return;
}
if (ret == sizeof (buf))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
buf[ret] = '\0';
fuse_reply_readlink (req, buf);
}
static int
hide_all (struct ovl_data *lo, struct ovl_node *node)
{
struct ovl_node *it;
for (it = hash_get_first (node->children); it; it = hash_get_next (node->children, it))
{
int ret;
ret = create_whiteout (lo, node, it->name);
if (ret < 0)
return ret;
}
return 0;
}
static void
ovl_mkdir (fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode)
{
struct ovl_node *node;
struct ovl_data *lo = ovl_data (req);
struct ovl_node *pnode;
int ret = 0;
char path[PATH_MAX + 10];
struct fuse_entry_param e;
if (ovl_debug (req))
fprintf (stderr, "ovl_mkdir(ino=%" PRIu64 ", name=%s, mode=%d)\n",
parent, name, mode);
node = do_lookup_file (lo, parent, name);
if (node != NULL)
{
fuse_reply_err (req, EEXIST);
return;
}
pnode = do_lookup_file (lo, parent, NULL);
if (pnode == NULL)
{
fuse_reply_err (req, ENOENT);
return;
}
pnode = get_node_up (lo, pnode);
if (pnode == NULL)
{
fuse_reply_err (req, errno);
return;
}
sprintf (path, "%s/%s", pnode->path, name);
unlinkat (get_upper_layer (lo)->fd, path, AT_REMOVEDIR);
ret = mkdirat (get_upper_layer (lo)->fd, path, mode);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
node = make_ovl_node (path, get_upper_layer (lo), name, 0, true);
if (node == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
node = insert_node (pnode, node, true);
if (node == NULL)
{
fuse_reply_err (req, ENOMEM);
return;
}
ret = hide_all (lo, node);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
if (delete_whiteout (lo, -1, pnode, name) < 0)
{
fuse_reply_err (req, errno);
return;
}
memset (&e, 0, sizeof (e));
ret = rpl_stat (req, node, &e.attr);
if (ret)
{
fuse_reply_err (req, errno);
return;
}
e.ino = NODE_TO_INODE (node);
e.attr_timeout = ATTR_TIMEOUT;
e.entry_timeout = ENTRY_TIMEOUT;
node->lookups++;
fuse_reply_entry (req, &e);
}
static void
ovl_fsync (fuse_req_t req, fuse_ino_t ino, int datasync, struct fuse_file_info *fi)
{
int ret, fd;
if (ovl_debug (req))
fprintf (stderr, "ovl_fsync(ino=%" PRIu64 ", datasync=%d, fi=%p)\n",
ino, datasync, fi);
fd = fi->fh;
ret = datasync ? fdatasync (fd) : fsync (fd);
fuse_reply_err (req, ret == 0 ? 0 : errno);
}
static struct fuse_lowlevel_ops ovl_oper =
{
.statfs = ovl_statfs,
.access = ovl_access,
.getxattr = ovl_getxattr,
.removexattr = ovl_removexattr,
.setxattr = ovl_setxattr,
.listxattr = ovl_listxattr,
.init = ovl_init,
.lookup = ovl_lookup,
.forget = ovl_forget,
.getattr = ovl_getattr,
.readlink = ovl_readlink,
.opendir = ovl_opendir,
.readdir = ovl_readdir,
.readdirplus = ovl_readdirplus,
.releasedir = ovl_releasedir,
.create = ovl_create,
.open = ovl_open,
.release = ovl_release,
.read = ovl_read,
.write_buf = ovl_write_buf,
.unlink = ovl_unlink,
.rmdir = ovl_rmdir,
.setattr = ovl_setattr,
.symlink = ovl_symlink,
.rename = ovl_rename,
.mkdir = ovl_mkdir,
.link = ovl_link,
.fsync = ovl_fsync,
.flock = ovl_flock,
};
static int
fuse_opt_proc (void *data, const char *arg, int key, struct fuse_args *outargs)
{
if (strcmp (arg, "-f") == 0)
return 1;
if (strcmp (arg, "--debug") == 0)
return 1;
if (strcmp (arg, "allow_root") == 0)
return 1;
if (strcmp (arg, "default_permissions") == 0)
return 1;
if (strcmp (arg, "allow_other") == 0)
return 1;
/* Ignore unknown arguments. */
if (key == -1)
return 0;
return 1;
}
char **
get_new_args (int *argc, char **argv)
{
int i;
char **newargv = malloc (sizeof (char *) * (*argc + 2));
newargv[0] = argv[0];
newargv[1] = "-odefault_permissions,allow_other";
for (i = 1; i < *argc; i++)
newargv[i + 1] = argv[i];
(*argc)++;
return newargv;
}
int
main (int argc, char *argv[])
{
struct fuse_session *se;
struct fuse_cmdline_opts opts;
char **newargv = get_new_args (&argc, argv);
struct ovl_data lo = {.debug = 0,
.uid_mappings = NULL,
.gid_mappings = NULL,
.uid_str = NULL,
.gid_str = NULL,
.root = NULL,
.lowerdir = NULL,
};
int ret = -1;
struct fuse_args args = FUSE_ARGS_INIT (argc, newargv);
if (fuse_opt_parse (&args, &lo, ovl_opts, fuse_opt_proc) == -1)
return 1;
if (fuse_parse_cmdline (&args, &opts) != 0)
return 1;
if (opts.show_help)
{
printf ("usage: %s [options] <mountpoint>\n\n", argv[0]);
fuse_cmdline_help ();
fuse_lowlevel_help ();
ret = 0;
goto err_out1;
}
else if (opts.show_version)
{
printf ("FUSE library version %s\n", fuse_pkgversion ());
fuse_lowlevel_version ();
ret = 0;
goto err_out1;
}
lo.debug = opts.debug;
if (lo.upperdir == NULL)
error (EXIT_FAILURE, 0, "upperdir not specified");
else
{
char full_path[PATH_MAX + 1];
if (realpath (lo.upperdir, full_path) < 0)
goto err_out1;
lo.upperdir = strdup (full_path);
if (lo.upperdir == NULL)
goto err_out1;
}
printf ("UID=%s\n", lo.uid_str ? : "unchanged");
printf ("GID=%s\n", lo.gid_str ? : "unchanged");
printf ("UPPERDIR=%s\n", lo.upperdir);
printf ("WORKDIR=%s\n", lo.workdir);
printf ("LOWERDIR=%s\n", lo.lowerdir);
printf ("MOUNTPOINT=%s\n", opts.mountpoint);
lo.uid_mappings = lo.uid_str ? read_mappings (lo.uid_str) : NULL;
lo.gid_mappings = lo.gid_str ? read_mappings (lo.gid_str) : NULL;
lo.layers = read_dirs (lo.lowerdir, true, NULL);
if (lo.layers == NULL)
error (EXIT_FAILURE, errno, "cannot read lower dirs");
lo.layers = read_dirs (lo.upperdir, false, lo.layers);
if (lo.layers == NULL)
error (EXIT_FAILURE, errno, "cannot read upper dir");
lo.root = load_dir (&lo, NULL, get_upper_layer (&lo), ".", "");
if (lo.root == NULL)
error (EXIT_FAILURE, errno, "cannot read upper dir");
lo.root->lookups = 2;
if (lo.workdir == NULL)
error (EXIT_FAILURE, 0, "workdir not specified");
else
{
char path[PATH_MAX + 1];
if (realpath (lo.workdir, path) < 0)
goto err_out1;
mkdir (path, 0700);
strcat (path, "/work");
mkdir (path, 0700);
free (lo.workdir);
lo.workdir = strdup (path);
lo.workdir_fd = open (lo.workdir, O_DIRECTORY);
if (lo.workdir_fd < 0)
goto err_out1;
}
se = fuse_session_new (&args, &ovl_oper, sizeof (ovl_oper), &lo);
lo.se = se;
if (se == NULL)
goto err_out1;
if (fuse_set_signal_handlers (se) != 0)
goto err_out2;
if (fuse_session_mount (se, opts.mountpoint) != 0)
goto err_out3;
fuse_daemonize (opts.foreground);
ret = fuse_session_loop (se);
fuse_session_unmount (se);
err_out3:
fuse_remove_signal_handlers (se);
err_out2:
fuse_session_destroy (se);
err_out1:
node_mark_all_free (lo.root);
node_free (lo.root);
free_mapping (lo.uid_mappings);
free_mapping (lo.gid_mappings);
close (lo.workdir_fd);
free_layers (lo.layers);
free (opts.mountpoint);
fuse_opt_free_args (&args);
return ret ? 1 : 0;
}
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