example/hello.c

   1 /*
   2     FUSE: Filesystem in Userspace
   3     Copyright (C) 2001-2006  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     gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
   9 */
  10
  11 #define FUSE_USE_VERSION 26
  12
  13 #include <fuse.h>
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <errno.h>
  17 #include <fcntl.h>
  18
  19 static const char *hello_str = "Hello World!\n";
  20 static const char *hello_path = "/hello";
  21
  22 static int hello_getattr(const char *path, struct stat *stbuf)
  23 {
  24     int res = 0;
  25
  26     memset(stbuf, 0, sizeof(struct stat));
  27     if (strcmp(path, "/") == 0) {
  28         stbuf->st_mode = S_IFDIR | 0755;
  29         stbuf->st_nlink = 2;
  30     } else if (strcmp(path, hello_path) == 0) {
  31         stbuf->st_mode = S_IFREG | 0444;
  32         stbuf->st_nlink = 1;
  33         stbuf->st_size = strlen(hello_str);
  34     } else
  35         res = -ENOENT;
  36
  37     return res;
  38 }
  39
  40 static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
  41                          off_t offset, struct fuse_file_info *fi)
  42 {
  43     (void) offset;
  44     (void) fi;
  45
  46     if (strcmp(path, "/") != 0)
  47         return -ENOENT;
  48
  49     filler(buf, ".", NULL, 0);
  50     filler(buf, "..", NULL, 0);
  51     filler(buf, hello_path + 1, NULL, 0);
  52
  53     return 0;
  54 }
  55
  56 static int hello_open(const char *path, struct fuse_file_info *fi)
  57 {
  58     if (strcmp(path, hello_path) != 0)
  59         return -ENOENT;
  60
  61     if ((fi->flags & 3) != O_RDONLY)
  62         return -EACCES;
  63
  64     return 0;
  65 }
  66
  67 static int hello_read(const char *path, char *buf, size_t size, off_t offset,
  68                       struct fuse_file_info *fi)
  69 {
  70     size_t len;
  71     (void) fi;
  72     if(strcmp(path, hello_path) != 0)
  73         return -ENOENT;
  74
  75     len = strlen(hello_str);
  76     if (offset < len) {
  77         if (offset + size > len)
  78             size = len - offset;
  79         memcpy(buf, hello_str + offset, size);
  80     } else
  81         size = 0;
  82
  83     return size;
  84 }
  85
  86 static struct fuse_operations hello_oper = {
  87     .getattr    = hello_getattr,
  88     .readdir    = hello_readdir,
  89     .open       = hello_open,
  90     .read       = hello_read,
  91 };
  92
  93 int main(int argc, char *argv[])
  94 {
  95     return fuse_main(argc, argv, &hello_oper, NULL);
  96 }