example/null.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 /** @file
  10  *
  11  * null.c - FUSE: Filesystem in Userspace
  12  *
  13  * \section section_compile compiling this example
  14  *
  15  * gcc -Wall null.c `pkg-config fuse3 --cflags --libs` -o null
  16  *
  17  * \section section_source the complete source
  18  * \include null.c
  19  */
  20
  21
  22 #define FUSE_USE_VERSION 30
  23
  24 #include <config.h>
  25
  26 #include <fuse.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <time.h>
  30 #include <errno.h>
  31
  32 static int null_getattr(const char *path, struct stat *stbuf)
  33 {
  34         if(strcmp(path, "/") != 0)
  35                 return -ENOENT;
  36
  37         stbuf->st_mode = S_IFREG | 0644;
  38         stbuf->st_nlink = 1;
  39         stbuf->st_uid = getuid();
  40         stbuf->st_gid = getgid();
  41         stbuf->st_size = (1ULL << 32); /* 4G */
  42         stbuf->st_blocks = 0;
  43         stbuf->st_atime = stbuf->st_mtime = stbuf->st_ctime = time(NULL);
  44
  45         return 0;
  46 }
  47
  48 static int null_truncate(const char *path, off_t size)
  49 {
  50         (void) size;
  51
  52         if(strcmp(path, "/") != 0)
  53                 return -ENOENT;
  54
  55         return 0;
  56 }
  57
  58 static int null_open(const char *path, struct fuse_file_info *fi)
  59 {
  60         (void) fi;
  61
  62         if(strcmp(path, "/") != 0)
  63                 return -ENOENT;
  64
  65         return 0;
  66 }
  67
  68 static int null_read(const char *path, char *buf, size_t size,
  69                      off_t offset, struct fuse_file_info *fi)
  70 {
  71         (void) buf;
  72         (void) offset;
  73         (void) fi;
  74
  75         if(strcmp(path, "/") != 0)
  76                 return -ENOENT;
  77
  78         if (offset >= (1ULL << 32))
  79                 return 0;
  80
  81         return size;
  82 }
  83
  84 static int null_write(const char *path, const char *buf, size_t size,
  85                       off_t offset, struct fuse_file_info *fi)
  86 {
  87         (void) buf;
  88         (void) offset;
  89         (void) fi;
  90
  91         if(strcmp(path, "/") != 0)
  92                 return -ENOENT;
  93
  94         return size;
  95 }
  96
  97 static struct fuse_operations null_oper = {
  98         .getattr        = null_getattr,
  99         .truncate       = null_truncate,
 100         .open           = null_open,
 101         .read           = null_read,
 102         .write          = null_write,
 103 };
 104
 105 int main(int argc, char *argv[])
 106 {
 107         return fuse_main(argc, argv, &null_oper, NULL);
 108 }