/*
fuse subdir module: offset paths with a base directory
Copyright (C) 2007 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU LGPLv2.
See the file COPYING.LIB
*/
#define FUSE_USE_VERSION 26
#include <fuse.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
struct subdir {
char *base;
size_t baselen;
int rellinks;
struct fuse_fs *next;
};
static struct subdir *subdir_get(void)
{
return fuse_get_context()->private_data;
}
static int subdir_addpath(struct subdir *d, const char *path, char **newpathp)
{
char *newpath = NULL;
if (path != NULL) {
unsigned newlen = d->baselen + strlen(path);
newpath = malloc(newlen + 2);
if (!newpath)
return -ENOMEM;
if (path[0] == '/')
path++;
strcpy(newpath, d->base);
strcpy(newpath + d->baselen, path);
if (!newpath[0])
strcpy(newpath, ".");
}
*newpathp = newpath;
return 0;
}
static int subdir_getattr(const char *path, struct stat *stbuf)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_getattr(d->next, newpath, stbuf);
free(newpath);
}
return err;
}
static int subdir_fgetattr(const char *path, struct stat *stbuf,
struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_fgetattr(d->next, newpath, stbuf, fi);
free(newpath);
}
return err;
}
static int subdir_access(const char *path, int mask)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_access(d->next, newpath, mask);
free(newpath);
}
return err;
}
static int count_components(const char *p)
{
int ctr;
for (; *p == '/'; p++);
for (ctr = 0; *p; ctr++) {
for (; *p && *p != '/'; p++);
for (; *p == '/'; p++);
}
return ctr;
}
static void strip_common(const char **sp, const char **tp)
{
const char *s = *sp;
const char *t = *tp;
do {
for (; *s == '/'; s++);
for (; *t == '/'; t++);
*tp = t;
*sp = s;
for (; *s == *t && *s && *s != '/'; s++, t++);
} while ((*s == *t && *s) || (!*s && *t == '/') || (*s == '/' && !*t));
}
static void transform_symlink(struct subdir *d, const char *path,
char *buf, size_t size)
{
const char *l = buf;
size_t llen;
char *s;
int dotdots;
int i;
if (l[0] != '/' || d->base[0] != '/')
return;
strip_common(&l, &path);
if (l - buf < (long) d->baselen)
return;
dotdots = count_components(path);
if (!dotdots)
return;
dotdots--;
llen = strlen(l);
if (dotdots * 3 + llen + 2 > size)
return;
s = buf + dotdots * 3;
if (llen)
memmove(s, l, llen + 1);
else if (!dotdots)
strcpy(s, ".");
else
*s = '\0';
for (s = buf, i = 0; i < dotdots; i++, s += 3)
memcpy(s, "../", 3);
}
static int subdir_readlink(const char *path, char *buf, size_t size)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_readlink(d->next, newpath, buf, size);
if (!err && d->rellinks)
transform_symlink(d, newpath, buf, size);
free(newpath);
}
return err;
}
static int subdir_opendir(const char *path, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_opendir(d->next, newpath, fi);
free(newpath);
}
return err;
}
static int subdir_readdir(const char *path, void *buf,
fuse_fill_dir_t filler, loff_t offset,
struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_readdir(d->next, newpath, buf, filler, offset,
fi);
free(newpath);
}
return err;
}
static int subdir_releasedir(const char *path, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_releasedir(d->next, newpath, fi);
free(newpath);
}
return err;
}
static int subdir_mknod(const char *path, mode_t mode, dev_t rdev)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_mknod(d->next, newpath, mode, rdev);
free(newpath);
}
return err;
}
static int subdir_mkdir(const char *path, mode_t mode)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_mkdir(d->next, newpath, mode);
free(newpath);
}
return err;
}
static int subdir_unlink(const char *path)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_unlink(d->next, newpath);
free(newpath);
}
return err;
}
static int subdir_rmdir(const char *path)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_rmdir(d->next, newpath);
free(newpath);
}
return err;
}
static int subdir_symlink(const char *from, const char *path)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_symlink(d->next, from, newpath);
free(newpath);
}
return err;
}
static int subdir_rename(const char *from, const char *to)
{
struct subdir *d = subdir_get();
char *newfrom;
char *newto;
int err = subdir_addpath(d, from, &newfrom);
if (!err) {
err = subdir_addpath(d, to, &newto);
if (!err) {
err = fuse_fs_rename(d->next, newfrom, newto);
free(newto);
}
free(newfrom);
}
return err;
}
static int subdir_link(const char *from, const char *to)
{
struct subdir *d = subdir_get();
char *newfrom;
char *newto;
int err = subdir_addpath(d, from, &newfrom);
if (!err) {
err = subdir_addpath(d, to, &newto);
if (!err) {
err = fuse_fs_link(d->next, newfrom, newto);
free(newto);
}
free(newfrom);
}
return err;
}
static int subdir_chmod(const char *path, mode_t mode)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_chmod(d->next, newpath, mode);
free(newpath);
}
return err;
}
static int subdir_chown(const char *path, uid_t uid, gid_t gid)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_chown(d->next, newpath, uid, gid);
free(newpath);
}
return err;
}
static int subdir_truncate(const char *path, loff_t size)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_truncate(d->next, newpath, size);
free(newpath);
}
return err;
}
static int subdir_ftruncate(const char *path, loff_t size,
struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_ftruncate(d->next, newpath, size, fi);
free(newpath);
}
return err;
}
static int subdir_utimens(const char *path, const struct timespec ts[2])
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_utimens(d->next, newpath, ts);
free(newpath);
}
return err;
}
static int subdir_create(const char *path, mode_t mode,
struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_create(d->next, newpath, mode, fi);
free(newpath);
}
return err;
}
static int subdir_open(const char *path, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_open(d->next, newpath, fi);
free(newpath);
}
return err;
}
static int subdir_read_buf(const char *path, struct fuse_bufvec **bufp,
size_t size, loff_t offset, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_read_buf(d->next, newpath, bufp, size, offset, fi);
free(newpath);
}
return err;
}
static int subdir_write_buf(const char *path, struct fuse_bufvec *buf,
loff_t offset, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_write_buf(d->next, newpath, buf, offset, fi);
free(newpath);
}
return err;
}
static int subdir_statfs(const char *path, struct statvfs *stbuf)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_statfs(d->next, newpath, stbuf);
free(newpath);
}
return err;
}
static int subdir_flush(const char *path, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_flush(d->next, newpath, fi);
free(newpath);
}
return err;
}
static int subdir_release(const char *path, struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_release(d->next, newpath, fi);
free(newpath);
}
return err;
}
static int subdir_fsync(const char *path, int isdatasync,
struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_fsync(d->next, newpath, isdatasync, fi);
free(newpath);
}
return err;
}
static int subdir_fsyncdir(const char *path, int isdatasync,
struct fuse_file_info *fi)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_fsyncdir(d->next, newpath, isdatasync, fi);
free(newpath);
}
return err;
}
static int subdir_setxattr(const char *path, const char *name,
const char *value, size_t size, int flags)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_setxattr(d->next, newpath, name, value, size,
flags);
free(newpath);
}
return err;
}
static int subdir_getxattr(const char *path, const char *name, char *value,
size_t size)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_getxattr(d->next, newpath, name, value, size);
free(newpath);
}
return err;
}
static int subdir_listxattr(const char *path, char *list, size_t size)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_listxattr(d->next, newpath, list, size);
free(newpath);
}
return err;
}
static int subdir_removexattr(const char *path, const char *name)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_removexattr(d->next, newpath, name);
free(newpath);
}
return err;
}
static int subdir_lock(const char *path, struct fuse_file_info *fi, int cmd,
struct flock *lock)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_lock(d->next, newpath, fi, cmd, lock);
free(newpath);
}
return err;
}
static int subdir_flock(const char *path, struct fuse_file_info *fi, int op)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_flock(d->next, newpath, fi, op);
free(newpath);
}
return err;
}
static int subdir_bmap(const char *path, size_t blocksize, uint64_t *idx)
{
struct subdir *d = subdir_get();
char *newpath;
int err = subdir_addpath(d, path, &newpath);
if (!err) {
err = fuse_fs_bmap(d->next, newpath, blocksize, idx);
free(newpath);
}
return err;
}
static void *subdir_init(struct fuse_conn_info *conn)
{
struct subdir *d = subdir_get();
fuse_fs_init(d->next, conn);
return d;
}
static void subdir_destroy(void *data)
{
struct subdir *d = data;
fuse_fs_destroy(d->next);
free(d->base);
free(d);
}
static const struct fuse_operations subdir_oper = {
.destroy = subdir_destroy,
.init = subdir_init,
.getattr = subdir_getattr,
.fgetattr = subdir_fgetattr,
.access = subdir_access,
.readlink = subdir_readlink,
.opendir = subdir_opendir,
.readdir = subdir_readdir,
.releasedir = subdir_releasedir,
.mknod = subdir_mknod,
.mkdir = subdir_mkdir,
.symlink = subdir_symlink,
.unlink = subdir_unlink,
.rmdir = subdir_rmdir,
.rename = subdir_rename,
.link = subdir_link,
.chmod = subdir_chmod,
.chown = subdir_chown,
.truncate = subdir_truncate,
.ftruncate = subdir_ftruncate,
.utimens = subdir_utimens,
.create = subdir_create,
.open = subdir_open,
.read_buf = subdir_read_buf,
.write_buf = subdir_write_buf,
.statfs = subdir_statfs,
.flush = subdir_flush,
.release = subdir_release,
.fsync = subdir_fsync,
.fsyncdir = subdir_fsyncdir,
.setxattr = subdir_setxattr,
.getxattr = subdir_getxattr,
.listxattr = subdir_listxattr,
.removexattr = subdir_removexattr,
.lock = subdir_lock,
.flock = subdir_flock,
.bmap = subdir_bmap,
.flag_nullpath_ok = 1,
.flag_nopath = 1,
};
static const struct fuse_opt subdir_opts[] = {
FUSE_OPT_KEY("-h", 0),
FUSE_OPT_KEY("--help", 0),
{ "subdir=%s", offsetof(struct subdir, base), 0 },
{ "rellinks", offsetof(struct subdir, rellinks), 1 },
{ "norellinks", offsetof(struct subdir, rellinks), 0 },
FUSE_OPT_END
};
static void subdir_help(void)
{
fprintf(stderr,
" -o subdir=DIR prepend this directory to all paths (mandatory)\n"
" -o [no]rellinks transform absolute symlinks to relative\n");
}
static int subdir_opt_proc(void *data, const char *arg, int key,
struct fuse_args *outargs)
{
(void) data; (void) arg; (void) outargs;
if (!key) {
subdir_help();
return -1;
}
return 1;
}
static struct fuse_fs *subdir_new(struct fuse_args *args,
struct fuse_fs *next[])
{
struct fuse_fs *fs;
struct subdir *d;
d = calloc(1, sizeof(struct subdir));
if (d == NULL) {
fprintf(stderr, "fuse-subdir: memory allocation failed\n");
return NULL;
}
if (fuse_opt_parse(args, d, subdir_opts, subdir_opt_proc) == -1)
goto out_free;
if (!next[0] || next[1]) {
fprintf(stderr, "fuse-subdir: exactly one next filesystem required\n");
goto out_free;
}
if (!d->base) {
fprintf(stderr, "fuse-subdir: missing 'subdir' option\n");
goto out_free;
}
if (d->base[0] && d->base[strlen(d->base)-1] != '/') {
char *tmp = realloc(d->base, strlen(d->base) + 2);
if (!tmp) {
fprintf(stderr, "fuse-subdir: memory allocation failed\n");
goto out_free;
}
d->base = tmp;
strcat(d->base, "/");
}
d->baselen = strlen(d->base);
d->next = next[0];
fs = fuse_fs_new(&subdir_oper, sizeof(subdir_oper), d);
if (!fs)
goto out_free;
return fs;
out_free:
free(d->base);
free(d);
return NULL;
}
FUSE_REGISTER_MODULE(subdir, subdir_new);
