static int unionfs_getattr(const char *path, struct stat *stbuf) {
DBG("%s\n", path);
if (uopt.stats_enabled && strcmp(path, STATS_FILENAME) == 0) {
memset(stbuf, 0, sizeof(stbuf));
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = STATS_SIZE;
RETURN(0);
}
int i = find_rorw_branch(path);
if (i == -1) RETURN(-errno);
char p[PATHLEN_MAX];
if (BUILD_PATH(p, uopt.branches[i].path, path)) RETURN(-ENAMETOOLONG);
int res = lstat(p, stbuf);
if (res == -1) RETURN(-errno);
/* This is a workaround for broken gnu find implementations. Actually,
* n_links is not defined at all for directories by posix. However, it
* seems to be common for filesystems to set it to one if the actual value
* is unknown. Since nlink_t is unsigned and since these broken implementations
* always substract 2 (for . and ..) this will cause an underflow, setting
* it to max(nlink_t).
*/
if (S_ISDIR(stbuf->st_mode)) stbuf->st_nlink = 1;
RETURN(0);
}
static int unionfs_open(const char *path, struct fuse_file_info *fi) {
DBG("%s\n", path);
int i;
if (fi->flags & (O_WRONLY | O_RDWR)) {
i = find_rw_branch_cutlast(path);
} else {
i = find_rorw_branch(path);
}
if (i == -1) RETURN(-errno);
char p[PATHLEN_MAX];
if (BUILD_PATH(p, uopt.branches[i].path, path)) RETURN(-ENAMETOOLONG);
int fd = open(p, fi->flags);
if (fd == -1) RETURN(-errno);
if (fi->flags & (O_WRONLY | O_RDWR)) {
// There might have been a hide file, but since we successfully
// wrote to the real file, a hide file must not exist anymore
remove_hidden(path, i);
}
// This makes exec() fail
//fi->direct_io = 1;
fi->fh = (unsigned long)fd;
DBG("fd = %"PRIx64"\n", fi->fh);
RETURN(0);
}
/**
* This is called *after* unlink() or rmdir(), create a whiteout file
* if the same file/dir does exist in a lower branch
*/
int maybe_whiteout(const char *path, int branch_rw, enum whiteout mode) {
DBG("%s\n", path);
// we are not interested in the branch itself, only if it exists at all
if (find_rorw_branch(path) != -1) {
int res = do_create_whiteout(path, branch_rw, mode);
RETURN(res);
}
RETURN(0);
}
static int unionfs_listxattr(const char *path, char *list, size_t size) {
DBG("%s\n", path);
int i = find_rorw_branch(path);
if (i == -1) RETURN(-errno);
char p[PATHLEN_MAX];
if (BUILD_PATH(p, uopt.branches[i].path, path)) RETURN(-ENAMETOOLONG);
int res = llistxattr(p, list, size);
if (res == -1) RETURN(-errno);
RETURN(res);
}
static int unionfs_readlink(const char *path, char *buf, size_t size) {
DBG("%s\n", path);
int i = find_rorw_branch(path);
if (i == -1) RETURN(-errno);
char p[PATHLEN_MAX];
if (BUILD_PATH(p, uopt.branches[i].path, path)) RETURN(-ENAMETOOLONG);
int res = readlink(p, buf, size - 1);
if (res == -1) RETURN(-errno);
buf[res] = '\0';
RETURN(0);
}
static int unionfs_getxattr(const char *path, const char *name, char *value, size_t size, uint32_t position) {
#else
static int unionfs_getxattr(const char *path, const char *name, char *value, size_t size) {
#endif
DBG("%s\n", path);
int i = find_rorw_branch(path);
if (i == -1) RETURN(-errno);
char p[PATHLEN_MAX];
if (BUILD_PATH(p, uopt.branches[i].path, path)) RETURN(-ENAMETOOLONG);
#if __APPLE__
int res = getxattr(p, name, value, size, position, XATTR_NOFOLLOW);
#else
int res = lgetxattr(p, name, value, size);
#endif
if (res == -1) RETURN(-errno);
RETURN(res);
}
/**
* unionfs rename function
* TODO: If we rename a directory on a read-only branch, we need to copy over
* all files to the renamed directory on the read-write branch.
*/
static int unionfs_rename(const char *from, const char *to) {
DBG("from %s to %s\n", from, to);
bool is_dir = false; // is 'from' a file or directory
int j = find_rw_branch_cutlast(to);
if (j == -1) RETURN(-errno);
int i = find_rorw_branch(from);
if (i == -1) RETURN(-errno);
if (!uopt.branches[i].rw) {
i = find_rw_branch_cow_common(from, true);
if (i == -1) RETURN(-errno);
}
if (i != j) {
USYSLOG(LOG_ERR, "%s: from and to are on different writable branches %d vs %d, which"
"is not supported yet.\n", __func__, i, j);
RETURN(-EXDEV);
}
char f[PATHLEN_MAX], t[PATHLEN_MAX];
if (BUILD_PATH(f, uopt.branches[i].path, from)) RETURN(-ENAMETOOLONG);
if (BUILD_PATH(t, uopt.branches[i].path, to)) RETURN(-ENAMETOOLONG);
filetype_t ftype = path_is_dir(f);
if (ftype == NOT_EXISTING)
RETURN(-ENOENT);
else if (ftype == IS_DIR)
is_dir = true;
int res;
if (!uopt.branches[i].rw) {
// since original file is on a read-only branch, we copied the from file to a writable branch,
// but since we will rename from, we also need to hide the from file on the read-only branch
if (is_dir)
res = hide_dir(from, i);
else
res = hide_file(from, i);
if (res) RETURN(-errno);
}
res = rename(f, t);
if (res == -1) {
int err = errno; // unlink() might overwrite errno
// if from was on a read-only branch we copied it, but now rename failed so we need to delete it
if (!uopt.branches[i].rw) {
if (unlink(f))
USYSLOG(LOG_ERR, "%s: cow of %s succeeded, but rename() failed and now "
"also unlink() failed\n", __func__, from);
if (remove_hidden(from, i))
USYSLOG(LOG_ERR, "%s: cow of %s succeeded, but rename() failed and now "
"also removing the whiteout failed\n", __func__, from);
}
RETURN(-err);
}
if (uopt.branches[i].rw) {
// A lower branch still *might* have a file called 'from', we need to delete this.
// We only need to do this if we have been on a rw-branch, since we created
// a whiteout for read-only branches anyway.
if (is_dir)
maybe_whiteout(from, i, WHITEOUT_DIR);
else
maybe_whiteout(from, i, WHITEOUT_FILE);
}
remove_hidden(to, i); // remove hide file (if any)
RETURN(0);
}
