2 * CIOPFS - The Case Insensitive On Purpose Filesystem for FUSE
4 * (c) 2008 Marc Andre Tanner <mat at brain-dump dot org>
5 * (c) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
7 * This program can be distributed under the terms of the GNU GPLv2.
10 * Before any operation takes place all filenames are
11 * converted to lower case. The original filenames are stored
12 * in extended attributes named user.filename. This value
13 * is returned upon request.
15 * Files or directories which aren't all lowercase in the
16 * underlying file system are ignored. You should probably
17 * start with an empty data directory and copy your contents
21 * In order to compile ciopfs, you will need both
22 * libfuse and libattr. Furthermore if you want a case
23 * preserving file system you have to make sure that the
24 * underlying file system supports extended attributes
25 * (for example for ext{2,3} you need a kernel with
26 * CONFIG_EXT{2,3}_FS_XATTR enabled). You probably also
27 * want to mount the underlying filesystem with the
28 * user_xattr option which allows non root users to create
29 * extended attributes.
31 * If you want to work with unicode characters within file
32 * names, you will need libicu from www.icu-project.org.
33 * Otherwise disable it in config.mk, the file system will
34 * only work with ascii [a-zA-Z] file names.
42 * ciopfs directory mountpoint [options]
47 #define _XOPEN_SOURCE 500 /* For pread()/pwrite() */
50 #define _BSD_SOURCE /* for vsyslog() */
54 #include <sys/xattr.h>
70 # define likely(x) __builtin_expect(!!(x), 1)
71 # define unlikely(x) __builtin_expect(!!(x), 0)
73 # define likely(x) (x)
74 # define unlikely(x) (x)
77 /* each *.c file implements the following two functions:
79 * static inline bool str_contains_upper(const char *s);
80 * static inline char *str_fold(const char *s);
83 # include "unicode-glib.c"
84 #elif defined HAVE_LIBICUUC
85 # include "unicode-icu.c"
90 #define log_print(format, args...) (*dolog)(format, ## args)
93 # define debug(format, args...)
95 # define debug log_print
98 #define CIOPFS_ATTR_NAME "user.filename"
101 #define PATH_MAX 4096
105 #define FILENAME_MAX 4096
108 static const char *dirname
;
109 /* whether we have forced fuse in single threaded mode (`-s' option). This happens
110 * because we can't store uid/gids per thread and the file system is accessible for
111 * multiple users via the `-o allow_other' option.
113 static bool single_threaded
= false;
115 void stderr_print(const char *fmt
, ...)
119 fputs("ciopfs: ", stderr
);
120 vfprintf(stderr
, fmt
, ap
);
124 void syslog_print(const char *fmt
, ...)
128 vsyslog(LOG_NOTICE
, fmt
, ap
);
132 static void (*dolog
)(const char *fmt
, ...) = syslog_print
;
134 static char *map_path(const char *path
)
137 /* XXX: memory fragmentation? */
138 if (path
[0] == '/') {
145 debug("%s => %s\n", path
, p
);
149 /* Returns the supplementary group IDs of a calling process which
150 * isued the file system operation.
152 * As indicated by Miklos Szeredi the group list is available in
154 * /proc/$PID/task/$TID/status
156 * and fuse supplies TID in get_fuse_context()->pid.
158 * Jean-Pierre Andre found out that the same information is also
161 * /proc/$TID/task/$TID/status
163 * which is used in this implementation.
166 static size_t get_groups(pid_t pid
, gid_t
**groups
)
168 static char key
[] = "\nGroups:\t";
169 char filename
[64], buf
[2048], *s
, *t
, c
= '\0';
170 int fd
, num_read
, matched
= 0;
172 gid_t
*gids
, grp
= 0;
174 sprintf(filename
, "/proc/%u/task/%u/status", pid
, pid
);
175 fd
= open(filename
, O_RDONLY
);
181 num_read
= read(fd
, buf
, sizeof(buf
) - 1);
186 buf
[num_read
] = '\0';
192 if (key
[matched
] == c
) {
197 matched
= (key
[0] == c
);
212 *groups
= gids
= malloc(n
* sizeof(gid_t
));
217 while ((c
= *s
++) != '\n') {
218 if (c
>= '0' && c
<= '9')
219 grp
= grp
*10 + c
- '0';
229 /* This only works when the filesystem is mounted by root and fuse
230 * operates in single threaded mode. Because the euid/egid are stored
231 * per process this would otherwise cause all sorts of race condidtions
232 * and security issues when multiple users access the file system
236 static inline void enter_user_context_effective()
240 struct fuse_context
*c
= fuse_get_context();
242 if (!single_threaded
|| getuid())
244 if ((ngroups
= get_groups(c
->pid
, &groups
))) {
245 setgroups(ngroups
, groups
);
253 static inline void leave_user_context_effective()
255 if (!single_threaded
|| getuid())
262 /* access(2) checks the real uid/gid not the effective one
263 * we therefore switch them if run as root and in single
266 * The real uid/gid are stored per process which is why we
267 * can't change them in multithreaded mode. This would lead
268 * to all sorts of race conditions and security issues when
269 * multiple users access the file system simultaneously.
273 static inline void enter_user_context_real()
277 struct fuse_context
*c
= fuse_get_context();
279 if (!single_threaded
|| geteuid())
281 if ((ngroups
= get_groups(c
->pid
, &groups
))) {
282 setgroups(ngroups
, groups
);
285 setregid(c
->gid
, -1);
286 setreuid(c
->uid
, -1);
289 static inline void leave_user_context_real()
291 if (!single_threaded
|| geteuid())
298 static ssize_t
ciopfs_get_orig_name(const char *path
, char *value
, size_t size
)
301 debug("looking up original file name of %s ", path
);
302 attrlen
= lgetxattr(path
, CIOPFS_ATTR_NAME
, value
, size
);
304 value
[attrlen
] = '\0';
305 debug("found %s\n", value
);
307 debug("nothing found\n");
312 static int ciopfs_set_orig_name_fd(int fd
, const char *origpath
)
314 char *filename
= strrchr(origpath
, '/');
316 filename
= (char *)origpath
;
320 char *path
= map_path(origpath
);
321 if (likely(path
!= NULL
)) {
322 log_print("storing original name '%s' in '%s'\n", filename
, path
);
326 if (fsetxattr(fd
, CIOPFS_ATTR_NAME
, filename
, strlen(filename
), 0)) {
327 debug("%s\n", strerror(errno
));
333 static int ciopfs_set_orig_name_path(const char *path
, const char *origpath
)
335 char *filename
= strrchr(origpath
, '/');
337 filename
= (char *)origpath
;
340 debug("storing original name '%s' in '%s'\n", filename
, path
);
341 /* XXX: setting an extended attribute on a symlink doesn't seem to work (EPERM) */
342 if (lsetxattr(path
, CIOPFS_ATTR_NAME
, filename
, strlen(filename
), 0)) {
343 debug("%s\n", strerror(errno
));
349 static int ciopfs_remove_orig_name(const char *path
)
351 debug("removing original file name of %s\n", path
);
352 return lremovexattr(path
, CIOPFS_ATTR_NAME
);
355 static int ciopfs_getattr(const char *path
, struct stat
*st_data
)
357 char *p
= map_path(path
);
358 if (unlikely(p
== NULL
))
360 enter_user_context_effective();
361 int res
= lstat(p
, st_data
);
362 leave_user_context_effective();
364 return (res
== -1) ? -errno
: 0;
367 static int ciopfs_fgetattr(const char *path
, struct stat
*stbuf
,
368 struct fuse_file_info
*fi
)
370 enter_user_context_effective();
371 int res
= fstat(fi
->fh
, stbuf
);
372 leave_user_context_effective();
378 static int ciopfs_readlink(const char *path
, char *buf
, size_t size
)
380 char *p
= map_path(path
);
381 if (unlikely(p
== NULL
))
383 enter_user_context_effective();
384 int res
= readlink(p
, buf
, size
- 1);
385 leave_user_context_effective();
393 static int ciopfs_opendir(const char *path
, struct fuse_file_info
*fi
)
395 char *p
= map_path(path
);
396 if (unlikely(p
== NULL
))
398 enter_user_context_effective();
399 DIR *dp
= opendir(p
);
400 leave_user_context_effective();
406 fi
->fh
= (uint64_t)(uintptr_t)dp
;
410 static int ciopfs_readdir(const char *path
, void *buf
, fuse_fill_dir_t filler
,
411 off_t offset
, struct fuse_file_info
*fi
)
414 DIR *dp
= (DIR *)(uintptr_t)fi
->fh
;
416 char *p
= map_path(path
);
417 if (unlikely(p
== NULL
))
419 size_t pathlen
= strlen(p
);
420 char dnamebuf
[PATH_MAX
];
421 char attrbuf
[FILENAME_MAX
];
423 if (pathlen
> PATH_MAX
) {
435 while ((de
= readdir(dp
)) != NULL
) {
440 /* skip any entry which is not all lower case for now */
441 if (str_contains_upper(de
->d_name
))
444 memset(&st
, 0, sizeof(st
));
445 st
.st_ino
= de
->d_ino
;
446 st
.st_mode
= de
->d_type
<< 12;
448 if (!strcmp(".", de
->d_name
) || !strcmp("..", de
->d_name
))
451 /* check whether there is an original name associated with
452 * this path and if so return it instead of the all lower
455 snprintf(dnamebuf
, sizeof dnamebuf
, "%s/%s", p
, de
->d_name
);
456 debug("dnamebuf: %s de->d_name: %s\n", dnamebuf
, de
->d_name
);
457 if (ciopfs_get_orig_name(dnamebuf
, attrbuf
, sizeof attrbuf
) > 0) {
458 /* we found an original name now check whether it is
459 * still accurate and if not remove it
461 attrlower
= str_fold(attrbuf
);
462 if (attrlower
&& !strcmp(attrlower
, de
->d_name
))
466 ciopfs_remove_orig_name(dnamebuf
);
472 debug("dname: %s\n", dname
);
473 if (filler(buf
, dname
, &st
, telldir(dp
)))
482 static int ciopfs_releasedir(const char *path
, struct fuse_file_info
*fi
)
485 closedir((DIR *)(uintptr_t)fi
->fh
);
489 static int ciopfs_mknod(const char *path
, mode_t mode
, dev_t rdev
)
492 char *p
= map_path(path
);
493 if (unlikely(p
== NULL
))
495 enter_user_context_effective();
496 /* On Linux this could just be 'mknod(p, mode, rdev)' but this
499 res
= open(p
, O_CREAT
| O_EXCL
| O_WRONLY
, mode
);
501 ciopfs_set_orig_name_fd(res
, path
);
504 } else if (S_ISFIFO(mode
)) {
505 res
= mkfifo(p
, mode
);
507 res
= mknod(p
, mode
, rdev
);
508 leave_user_context_effective();
516 static int ciopfs_mkdir(const char *path
, mode_t mode
)
519 char *p
= map_path(path
);
520 if (unlikely(p
== NULL
))
522 enter_user_context_effective();
523 int res
= mkdir(p
, mode
);
524 leave_user_context_effective();
531 ciopfs_set_orig_name_path(p
, path
);
537 static int ciopfs_unlink(const char *path
)
539 char *p
= map_path(path
);
540 if (unlikely(p
== NULL
))
542 enter_user_context_effective();
544 leave_user_context_effective();
551 static int ciopfs_rmdir(const char *path
)
553 char *p
= map_path(path
);
554 if (unlikely(p
== NULL
))
556 enter_user_context_effective();
558 leave_user_context_effective();
565 static int ciopfs_symlink(const char *from
, const char *to
)
568 char *t
= map_path(to
);
569 if (unlikely(t
== NULL
))
571 enter_user_context_effective();
572 int res
= symlink(from
, t
);
573 leave_user_context_effective();
578 ciopfs_set_orig_name_path(t
, to
);
584 static int ciopfs_rename(const char *from
, const char *to
)
587 char *f
= map_path(from
);
588 char *t
= map_path(to
);
589 if (unlikely(f
== NULL
|| t
== NULL
))
591 enter_user_context_effective();
592 int res
= rename(f
, t
);
593 leave_user_context_effective();
598 ciopfs_set_orig_name_path(t
, to
);
605 static int ciopfs_link(const char *from
, const char *to
)
608 char *f
= map_path(from
);
609 char *t
= map_path(to
);
610 if (unlikely(f
== NULL
|| t
== NULL
))
612 enter_user_context_effective();
613 int res
= link(f
, t
);
614 leave_user_context_effective();
619 ciopfs_set_orig_name_path(t
, to
);
626 static int ciopfs_chmod(const char *path
, mode_t mode
)
628 char *p
= map_path(path
);
629 if (unlikely(p
== NULL
))
631 enter_user_context_effective();
632 int res
= chmod(p
, mode
);
633 leave_user_context_effective();
640 static int ciopfs_chown(const char *path
, uid_t uid
, gid_t gid
)
642 char *p
= map_path(path
);
643 if (unlikely(p
== NULL
))
645 enter_user_context_effective();
646 int res
= lchown(p
, uid
, gid
);
647 leave_user_context_effective();
654 static int ciopfs_truncate(const char *path
, off_t size
)
656 char *p
= map_path(path
);
657 if (unlikely(p
== NULL
))
659 enter_user_context_effective();
660 int res
= truncate(p
, size
);
661 leave_user_context_effective();
668 static int ciopfs_ftruncate(const char *path
, off_t size
, struct fuse_file_info
*fi
)
670 enter_user_context_effective();
671 int res
= ftruncate(fi
->fh
, size
);
672 leave_user_context_effective();
679 static int ciopfs_utimens(const char *path
, const struct timespec ts
[2])
681 char *p
= map_path(path
);
682 if (unlikely(p
== NULL
))
684 struct timeval tv
[2];
686 tv
[0].tv_sec
= ts
[0].tv_sec
;
687 tv
[0].tv_usec
= ts
[0].tv_nsec
/ 1000;
688 tv
[1].tv_sec
= ts
[1].tv_sec
;
689 tv
[1].tv_usec
= ts
[1].tv_nsec
/ 1000;
691 enter_user_context_effective();
692 int res
= utimes(p
, tv
);
693 leave_user_context_effective();
700 static int ciopfs_create(const char *path
, mode_t mode
, struct fuse_file_info
*fi
)
702 char *p
= map_path(path
);
703 if (unlikely(p
== NULL
))
705 enter_user_context_effective();
706 int fd
= open(p
, fi
->flags
, mode
);
707 leave_user_context_effective();
711 ciopfs_set_orig_name_fd(fd
, path
);
716 static int ciopfs_open(const char *path
, struct fuse_file_info
*fi
)
718 char *p
= map_path(path
);
719 if (unlikely(p
== NULL
))
721 enter_user_context_effective();
722 int fd
= open(p
, fi
->flags
);
723 leave_user_context_effective();
727 if (fi
->flags
& O_CREAT
)
728 ciopfs_set_orig_name_fd(fd
, path
);
733 static int ciopfs_read(const char *path
, char *buf
, size_t size
, off_t offset
,
734 struct fuse_file_info
*fi
)
736 int res
= pread(fi
->fh
, buf
, size
, offset
);
742 static int ciopfs_write(const char *path
, const char *buf
, size_t size
,
743 off_t offset
, struct fuse_file_info
*fi
)
745 int res
= pwrite(fi
->fh
, buf
, size
, offset
);
751 static int ciopfs_statfs(const char *path
, struct statvfs
*stbuf
)
753 char *p
= map_path(path
);
754 if (unlikely(p
== NULL
))
756 enter_user_context_effective();
757 int res
= statvfs(p
, stbuf
);
758 leave_user_context_effective();
766 static int ciopfs_flush(const char *path
, struct fuse_file_info
*fi
)
768 /* This is called from every close on an open file, so call the
769 close on the underlying filesystem. But since flush may be
770 called multiple times for an open file, this must not really
771 close the file. This is important if used on a network
772 filesystem like NFS which flush the data/metadata on close() */
773 int res
= close(dup(fi
->fh
));
780 static int ciopfs_release(const char *path
, struct fuse_file_info
*fi
)
786 static int ciopfs_fsync(const char *path
, int isdatasync
, struct fuse_file_info
*fi
)
789 #ifdef HAVE_FDATASYNC
791 res
= fdatasync(fi
->fh
);
800 static int ciopfs_access(const char *path
, int mode
)
802 char *p
= map_path(path
);
803 if (unlikely(p
== NULL
))
805 enter_user_context_real();
806 int res
= access(p
, mode
);
807 leave_user_context_real();
814 static int ciopfs_setxattr(const char *path
, const char *name
, const char *value
,
815 size_t size
, int flags
)
817 if (!strcmp(name
, CIOPFS_ATTR_NAME
)) {
818 debug("denying setting value of extended attribute '%s'\n", CIOPFS_ATTR_NAME
);
821 char *p
= map_path(path
);
822 if (unlikely(p
== NULL
))
824 enter_user_context_effective();
825 int res
= lsetxattr(p
, name
, value
, size
, flags
);
826 leave_user_context_effective();
833 static int ciopfs_getxattr(const char *path
, const char *name
, char *value
, size_t size
)
835 char *p
= map_path(path
);
836 if (unlikely(p
== NULL
))
838 enter_user_context_effective();
839 int res
= lgetxattr(p
, name
, value
, size
);
840 leave_user_context_effective();
847 static int ciopfs_listxattr(const char *path
, char *list
, size_t size
)
849 char *p
= map_path(path
);
850 if (unlikely(p
== NULL
))
852 enter_user_context_effective();
853 int res
= llistxattr(p
, list
, size
);
854 leave_user_context_effective();
861 static int ciopfs_removexattr(const char *path
, const char *name
)
863 if (!strcmp(name
, CIOPFS_ATTR_NAME
)) {
864 debug("denying removal of extended attribute '%s'\n", CIOPFS_ATTR_NAME
);
867 char *p
= map_path(path
);
868 if (unlikely(p
== NULL
))
870 enter_user_context_effective();
871 int res
= lremovexattr(p
, name
);
872 leave_user_context_effective();
879 static int ciopfs_lock(const char *path
, struct fuse_file_info
*fi
, int cmd
,
882 return ulockmgr_op(fi
->fh
, cmd
, lock
, &fi
->lock_owner
,
883 sizeof(fi
->lock_owner
));
886 static void *ciopfs_init(struct fuse_conn_info
*conn
)
888 if (chdir(dirname
) == -1) {
889 log_print("init: %s\n", strerror(errno
));
895 struct fuse_operations ciopfs_operations
= {
896 .getattr
= ciopfs_getattr
,
897 .fgetattr
= ciopfs_fgetattr
,
898 .readlink
= ciopfs_readlink
,
899 .opendir
= ciopfs_opendir
,
900 .readdir
= ciopfs_readdir
,
901 .releasedir
= ciopfs_releasedir
,
902 .mknod
= ciopfs_mknod
,
903 .mkdir
= ciopfs_mkdir
,
904 .symlink
= ciopfs_symlink
,
905 .unlink
= ciopfs_unlink
,
906 .rmdir
= ciopfs_rmdir
,
907 .rename
= ciopfs_rename
,
909 .chmod
= ciopfs_chmod
,
910 .chown
= ciopfs_chown
,
911 .truncate
= ciopfs_truncate
,
912 .ftruncate
= ciopfs_ftruncate
,
913 .utimens
= ciopfs_utimens
,
914 .create
= ciopfs_create
,
917 .write
= ciopfs_write
,
918 .statfs
= ciopfs_statfs
,
919 .flush
= ciopfs_flush
,
920 .release
= ciopfs_release
,
921 .fsync
= ciopfs_fsync
,
922 .access
= ciopfs_access
,
923 .setxattr
= ciopfs_setxattr
,
924 .getxattr
= ciopfs_getxattr
,
925 .listxattr
= ciopfs_listxattr
,
926 .removexattr
= ciopfs_removexattr
,
931 static void usage(const char *name
)
933 fprintf(stderr
, "usage: %s directory mountpoint [options]\n"
935 "Mounts the content of directory at mountpoint in case insensitiv fashion.\n"
938 " -o opt,[opt...] mount options\n"
939 " -h|--help print help\n"
940 " --version print version\n"
950 static int ciopfs_opt_parse(void *data
, const char *arg
, int key
, struct fuse_args
*outargs
)
953 case FUSE_OPT_KEY_NONOPT
:
955 /* realpath(char *s, NULL) is a POSIX.1-2008 extension, originally from GLIBC,
956 and might be unavailible on older non-glibc systems. */
957 if (!(dirname
= realpath(arg
, NULL
))) {
958 perror(outargs
->argv
[0]);
964 case FUSE_OPT_KEY_OPT
:
969 dolog
= stderr_print
;
971 } else if (!strcmp("allow_other", arg
)) {
972 /* disable multithreaded mode if the file system
973 * is accessible to multiple users simultanousely
974 * because we can't store uid/gid per thread and
975 * this leads to all sorts of race conditions and
978 single_threaded
= (getuid() == 0);
981 case CIOPFS_OPT_HELP
:
982 usage(outargs
->argv
[0]);
983 fuse_opt_add_arg(outargs
, "-ho");
984 fuse_main(outargs
->argc
, outargs
->argv
, &ciopfs_operations
, NULL
);
986 case CIOPFS_OPT_VERSION
:
987 fprintf(stderr
, "%s: "VERSION
" fuse: %d\n", outargs
->argv
[0], fuse_version());
990 fprintf(stderr
, "see `%s -h' for usage\n", outargs
->argv
[0]);
996 static struct fuse_opt ciopfs_opts
[] = {
997 FUSE_OPT_KEY("-h", CIOPFS_OPT_HELP
),
998 FUSE_OPT_KEY("--help", CIOPFS_OPT_HELP
),
999 FUSE_OPT_KEY("--version", CIOPFS_OPT_VERSION
),
1003 int main(int argc
, char *argv
[])
1005 struct fuse_args args
= FUSE_ARGS_INIT(argc
, argv
);
1006 fuse_opt_parse(&args
, &dirname
, ciopfs_opts
, ciopfs_opt_parse
);
1008 if (single_threaded
) {
1009 fuse_opt_add_arg(&args
, "-s");
1010 log_print("disabling multithreaded mode for root mounted "
1011 "filesystem that is accessible for other users "
1012 "via the `-o allow_other' option\n");
1016 return fuse_main(args
.argc
, args
.argv
, &ciopfs_operations
, NULL
);