fs/nullfs.c

   1 /*
   2  * Copyright (C) 2005 by Latchesar Ionkov <lucho@ionkov.net>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * LATCHESAR IONKOV AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23 #define _XOPEN_SOURCE 600
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <pthread.h>
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <assert.h>
  32 #include "npfs.h"
  33
  34 static Npfile* null_first(Npfile *);
  35 static Npfile* null_next(Npfile *, Npfile *);
  36 static int null_read(Npfilefid *, u64, u32, u8*, Npreq *);
  37 static int null_write(Npfilefid *, u64, u32, u8*, Npreq *);
  38 static int null_wstat(Npfile *, Npstat *);
  39 static void null_connclose(Npconn *);
  40
  41 static Npsrv *srv;
  42 static Npfile *root;
  43 static Npfile * null;
  44 static Npdirops rootops = {
  45         .first = null_first,
  46         .next = null_next,
  47 };
  48
  49 static Npfileops nullops = {
  50         .read = null_read,
  51         .write = null_write,
  52         .wstat = null_wstat,
  53 };
  54
  55 static void
  56 usage()
  57 {
  58         fprintf(stderr, "nullfs: -d -w nthreads mount-point\n");
  59         exit(-1);
  60 }
  61
  62 int
  63 main(int argc, char **argv)
  64 {
  65         int c, debuglevel, nwthreads;
  66         pid_t pid;
  67         Npuser *user;
  68         char *opts, *s;
  69
  70         debuglevel = 0;
  71         nwthreads = 16;
  72         user = np_default_users->uid2user(np_default_users, getuid());
  73         while ((c = getopt(argc, argv, "dw:")) != -1) {
  74                 switch (c) {
  75                 case 'd':
  76                         debuglevel = 1;
  77                         break;
  78
  79                 case 'w':
  80                         nwthreads = strtol(optarg, &s, 10);
  81                         if (*s != '\0')
  82                                 usage();
  83                         break;
  84
  85                 default:
  86                         fprintf(stderr, "invalid option\n");
  87                 }
  88         }
  89
  90         if (optind >= argc)
  91                 usage();
  92
  93         if (!user) {
  94                 fprintf(stderr, "invalid user\n");
  95                 return -1;
  96         }
  97
  98         close(0);
  99         close(1);
 100         close(2);
 101         pid = fork();
 102         if (pid < 0)
 103                 return -1;
 104         else if (pid != 0)
 105                 return 0;
 106
 107         setsid();
 108         chdir("/");
 109
 110         root = npfile_alloc(NULL, strdup(""), 0755|Dmdir, 0, &rootops, NULL);
 111         root->parent = root;
 112         npfile_incref(root);
 113         root->atime = time(NULL);
 114         root->mtime = root->atime;
 115         root->uid = user;
 116         root->gid = user->dfltgroup;
 117         root->muid = user;
 118
 119         null = npfile_alloc(root, strdup("null"), 0644, 1, &nullops, NULL);
 120         npfile_incref(null);
 121         root->dirfirst = null;
 122         root->dirlast = null;
 123
 124         srv = np_pipesrv_create(nwthreads);
 125         if (!srv)
 126                 return -1;
 127
 128         srv->debuglevel = debuglevel;
 129         srv->connclose = null_connclose;
 130         npfile_init_srv(srv, root);
 131
 132         np_pipesrv_mount(srv, argv[optind], user->uname, 0, opts);
 133
 134
 135         while (1) {
 136                 sleep(100);
 137         }
 138
 139         return 0;
 140 }
 141
 142 static void
 143 null_connclose(Npconn *conn)
 144 {
 145         exit(0);
 146 }
 147
 148 static Npfile*
 149 null_first(Npfile *dir)
 150 {
 151         if (dir->dirfirst)
 152                 npfile_incref(dir->dirfirst);
 153
 154         return dir->dirfirst;
 155 }
 156
 157 static Npfile*
 158 null_next(Npfile *dir, Npfile *prevchild)
 159 {
 160         if (prevchild->next)
 161                 npfile_incref(prevchild->next);
 162
 163         return prevchild->next;
 164 }
 165
 166 static int
 167 null_read(Npfilefid* file, u64 offset, u32 count, u8* data, Npreq *req)
 168 {
 169         memset(data, 0, count);
 170         return count;
 171 }
 172
 173 static int
 174 null_write(Npfilefid* file, u64 offset, u32 count, u8* data, Npreq *req)
 175 {
 176         return count;
 177 }
 178
 179 static int
 180 null_wstat(Npfile* file, Npstat* stat)
 181 {
 182         return 1;
 183 }