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Diffstat (limited to 'lib/libfuse/fuse.3')
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diff --git a/lib/libfuse/fuse.3 b/lib/libfuse/fuse.3 new file mode 100644 index 00000000000..931cb0d2f55 --- /dev/null +++ b/lib/libfuse/fuse.3 @@ -0,0 +1,241 @@ +.\" +.\" Copyright (c) 2013 Sylvestre Gallon <ccna.syl@gmail.com> +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.Dd $Mdocdate: June 3 2013 $ +.Dt FUSE 3 +.Os +.Sh NAME +.Nm fuse , +.Nm fuse_main , +.Nm fuse_new , +.Nm fuse_parse_cmdline , +.Nm fuse_mount , +.Nm fuse_remove_signal_handlers , +.Nm fuse_set_signal_handlers , +.Nm fuse_get_session , +.Nm fuse_is_lib_option , +.Nm fuse_loop , +.Nm fuse_loop_mt , +.Nm fuse_chan_fd , +.Nm fuse_unmount , +.Nm fuse_daemonize, +.Nm fuse_destroy +.Nd FUSE implementation routines +.Sh SYNOPSIS +.Fd #include \*[Lt]fuse.h\*[Gt] +.Ft int +.Fn fuse_main "int argc" "char **argv" "const struct fuse_operations *ops" \ + "void *data" +.Ft struct fuse * +.Fn fuse_new "struct fuse_chan *fc" "struct fuse_args *args" \ + "const struct fuse_operations *ops" "size_t size" "void *userdata" +.Ft int +.Fn fuse_parse_cmdline "struct fuse_args *args" "char **mp" "int *mt" "int *fg" +.Ft struct fuse_chan * +.Fn fuse_mount "const char *dir" "struct fuse_args *args" +.Ft void +.Fn fuse_remove_signal_handlers "struct fuse_session *se" +.Ft int +.Fn fuse_set_signal_handlers "struct fuse_session *se" +.Ft struct fuse_session * +.Fn fuse_get_session "struct fuse *f" +.Ft int +.Fn fuse_is_lib_option "const char *opt" +.Ft int +.Fn fuse_loop "struct fuse *fuse" +.Ft int +.Fn fuse_loop_mt "struct fuse *fuse" +.Ft int +.Fn fuse_chan_fd "struct fuse_chan *ch" +.Ft void +.Fn fuse_unmount "const char *dir" "struct fuse_chan *ch" +.Ft int +.Fn fuse_daemonize "int foreground" +.Ft void +.Fn fuse_destroy "struct fuse *f" +.Sh DESCRIPTION +The +.Nm +library provides routine to implement a filesystem in userspace. +.Ss INTRODUCTION +There is two way of Implementing a Fuse filesystem. You can implement a fs only +by calling +.Fn fuse_main +and giving this function the +.Em ops +argument containing all the callbacks of your filesystems. Or you can use all +others functions. +.Ss FUNCTIONS +.Fn fuse_new +Fuse new return a +.Fa struct fuse +That will be needed by +.Fn fuse_loop +.Pp +.Fn fuse_parse_cmdline +This function will parse the +.Fa struct fuse_args +given by the user and will set +.Fa mp +with a char * containing the mountpoint directory. +.Pp +.Fn fuse_mount +Will look for an empty +.Xr fuse 4 +device to create a connection. If this function find an available device it will +open it to use it for fuse communication with the fuse VFS driver and will mount +the filesystem. This function will return a +.Fa struct fuse_chan +that will be needed by +.Fn fuse_new +.Pp +.Fn fuse_remove_signal_handlers +I do not know yet what this function is supposed to do... +.Pp +.Fn fuse_set_signal_handlers +I do not know yet what this function is supposed to do... +.Pp +.Fn fuse_get_session +returns a pointer on the structure +.Fa fuse_session +contained in a +.Fa struct fuse +.Pp +.Fn fuse_is_lib_option +check if the string +.Fa opt +is an option handled by the libfuse or by the fuse client. It returns 1 if it is +handled by the lib and 0 in the other case. +.Pp +.Fn fuse_loop_mt +Do not use! It is not supported yet (and we will probably never need it...) +.Pp +.Fn fuse_loop +This is the mainloop of a fuse program. This function will look for fuse +request from kernel and will respond to it using the +.Fa struct fuse_operation +present in the structure +.Fa fuse. +It will return only if something goes wrong +or if the kernel send a +.Fa FUSE_DESTROY +opcode to libfuse. +.Pp +.Fn fuse_chan_fd +returns the filedescriptor used by the given +.Fa fuse_chan +structure. +.Pp +.Fn fuse_unmount +unmount the +.Fa dir +mountpoint. +.Pp +.Fn fuse_daemonize +daemonise the fuse library. It will permit to background the fuse program that +will continue to handles kernel filesystems opcodes. +.Pp +.Fn fuse_destroy +I do not know yet what this function is supposed to do... +.Sh EXAMPLE +Here is a simple example of a fuse implementation: +.Bd -literal +#include <errno.h> +#include <fuse.h> +#include <string.h> + +static int +fs_readdir(const char *path, void *data, fuse_fill_dir_t filler, + off_t off, struct fuse_file_info *ffi) +{ + if (strcmp(path, "/") != 0) + return (-ENOENT); + + filler(data, ".", NULL, 0); + filler(data, "..", NULL, 0); + filler(data, "file", NULL, 0); + return (0); +} + +static int +fs_read(const char *path, char *buf, size_t size, off_t off, + struct fuse_file_info *ffi) +{ + if (off >= 5) + return (0); + + size = 5 - off; + memcpy(buf, "data." + off, size); + return (size); +} + +static int +fs_open(const char *path, struct fuse_file_info *ffi) +{ + if (strncmp(path, "/file", 10) != 0) + return (-ENOENT); + + if ((ffi->flags & 3) != O_RDONLY) + return (-EACCES); + + return (0); +} + +static int +fs_getattr(const char *path, struct stat *st) +{ + if (strcmp(path, "/") == 0) { + st->st_blksize = 512; + st->st_mode = 0755; + st->st_nlink = 2; + } else if (strcmp(path, "/file") == 0) { + st->st_mode = 0644; + st->st_blksize = 512; + st->st_nlink = 1; + st->st_size = 5; + } else { + return (-ENOENT); + } + + return (0); +} + +struct fuse_operations fsops = { + .readdir = fs_readdir, + .read = fs_read, + .open = fs_open, + .getattr = fs_getattr, +}; + +int +main(int ac, char **av) +{ + return (fuse_main(ac, av, &fsops, NULL)); +} +.Ed +.Sh SEE ALSO +The +.Tn FUSE +specifications and orignal implementation can be found at: +.Lk http://fuse.sourceforge.net/ +.Pp +.Xr fuse 4 +.Sh HISTORY +The +.Nm +library first appeared in +.Ox ??? . +.Sh BUGS +This man page is woefully incomplete |