printcap.c File Reference

#include <fuse_lowlevel.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>

Go to the source code of this file.

Detailed Description

minimal example filesystem that prints out all capabilities supported by the kernel and then exits.

Compile with:

gcc -Wall printcap.c `pkg-config fuse3 --cflags --libs` -o printcap

Source code

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2017 Nikolaus Rath <Nikolaus@rath.org>
 
  This program can be distributed under the terms of the GNU GPLv2.
  See the file COPYING.
*/
 
#define FUSE_USE_VERSION 31
 
#include <fuse_lowlevel.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
 
struct fuse_session *se;
 
static void pc_init(void *userdata,
                    struct fuse_conn_info *conn)
{
        (void) userdata;
        
        printf("Protocol version: %d.%d\n", conn->proto_major,
               conn->proto_minor);
        printf("Capabilities:\n");
        if(conn->capable & FUSE_CAP_ASYNC_READ)
                        printf("\tFUSE_CAP_ASYNC_READ\n");
        if(conn->capable & FUSE_CAP_POSIX_LOCKS)
                        printf("\tFUSE_CAP_POSIX_LOCKS\n");
        if(conn->capable & FUSE_CAP_ATOMIC_O_TRUNC)
                        printf("\tFUSE_CAP_ATOMIC_O_TRUNC\n");
        if(conn->capable & FUSE_CAP_EXPORT_SUPPORT)
                        printf("\tFUSE_CAP_EXPORT_SUPPORT\n");
        if(conn->capable & FUSE_CAP_DONT_MASK)
                        printf("\tFUSE_CAP_DONT_MASK\n");
        if(conn->capable & FUSE_CAP_SPLICE_MOVE)
                        printf("\tFUSE_CAP_SPLICE_MOVE\n");
        if(conn->capable & FUSE_CAP_SPLICE_READ)
                        printf("\tFUSE_CAP_SPLICE_READ\n");
        if(conn->capable & FUSE_CAP_SPLICE_WRITE)
                        printf("\tFUSE_CAP_SPLICE_WRITE\n");
        if(conn->capable & FUSE_CAP_FLOCK_LOCKS)
                        printf("\tFUSE_CAP_FLOCK_LOCKS\n");
        if(conn->capable & FUSE_CAP_IOCTL_DIR)
                        printf("\tFUSE_CAP_IOCTL_DIR\n");
        if(conn->capable & FUSE_CAP_AUTO_INVAL_DATA)
                        printf("\tFUSE_CAP_AUTO_INVAL_DATA\n");
        if(conn->capable & FUSE_CAP_READDIRPLUS)
                        printf("\tFUSE_CAP_READDIRPLUS\n");
        if(conn->capable & FUSE_CAP_READDIRPLUS_AUTO)
                        printf("\tFUSE_CAP_READDIRPLUS_AUTO\n");
        if(conn->capable & FUSE_CAP_ASYNC_DIO)
                        printf("\tFUSE_CAP_ASYNC_DIO\n");
        if(conn->capable & FUSE_CAP_WRITEBACK_CACHE)
                        printf("\tFUSE_CAP_WRITEBACK_CACHE\n");
        if(conn->capable & FUSE_CAP_NO_OPEN_SUPPORT)
                        printf("\tFUSE_CAP_NO_OPEN_SUPPORT\n");
        if(conn->capable & FUSE_CAP_PARALLEL_DIROPS)
                        printf("\tFUSE_CAP_PARALLEL_DIROPS\n");
        if(conn->capable & FUSE_CAP_POSIX_ACL)
                        printf("\tFUSE_CAP_POSIX_ACL\n");
        if(conn->capable & FUSE_CAP_CACHE_SYMLINKS)
                        printf("\tFUSE_CAP_CACHE_SYMLINKS\n");
        if(conn->capable & FUSE_CAP_NO_OPENDIR_SUPPORT)
                        printf("\tFUSE_CAP_NO_OPENDIR_SUPPORT\n");
        if(conn->capable & FUSE_CAP_EXPLICIT_INVAL_DATA)
                        printf("\tFUSE_CAP_EXPLICIT_INVAL_DATA\n");
        if(conn->capable & FUSE_CAP_EXPIRE_ONLY)
                        printf("\tFUSE_CAP_EXPIRE_ONLY\n");
        fuse_session_exit(se);
}
 
 
static const struct fuse_lowlevel_ops pc_oper = {
        .init           = pc_init,
};
 
int main(int argc, char **argv)
{
        struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
        char *mountpoint;
        int ret = -1;
 
        mountpoint = strdup("/tmp/fuse_printcap_XXXXXX");
        if(mkdtemp(mountpoint) == NULL) {
                perror("mkdtemp");
                return 1;
        }
        
        printf("FUSE library version %s\n", fuse_pkgversion());
        fuse_lowlevel_version();
 
        se = fuse_session_new(&args, &pc_oper,
                              sizeof(pc_oper), NULL);
        if (se == NULL)
            goto err_out1;
 
        if (fuse_set_signal_handlers(se) != 0)
            goto err_out2;
 
        if (fuse_session_mount(se, mountpoint) != 0)
            goto err_out3;
 
        ret = fuse_session_loop(se);
 
        fuse_session_unmount(se);
err_out3:
        fuse_remove_signal_handlers(se);
err_out2:
        fuse_session_destroy(se);
err_out1:
        rmdir(mountpoint);
        free(mountpoint);
        fuse_opt_free_args(&args);
 
        return ret ? 1 : 0;
}

Definition in file printcap.c.