tools/virtiofsd/helper.c

   1 /*
   2  * FUSE: Filesystem in Userspace
   3  * Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
   4  *
   5  * Helper functions to create (simple) standalone programs. With the
   6  * aid of these functions it should be possible to create full FUSE
   7  * file system by implementing nothing but the request handlers.
   8
   9  * This program can be distributed under the terms of the GNU LGPLv2.
  10  * See the file COPYING.LIB.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "fuse_i.h"
  15 #include "fuse_lowlevel.h"
  16 #include "fuse_misc.h"
  17 #include "fuse_opt.h"
  18
  19 #include <errno.h>
  20 #include <limits.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/param.h>
  26 #include <unistd.h>
  27
  28 #define FUSE_HELPER_OPT(t, p)                       \
  29     {                                               \
  30         t, offsetof(struct fuse_cmdline_opts, p), 1 \
  31     }
  32 #define FUSE_HELPER_OPT_VALUE(t, p, v)              \
  33     {                                               \
  34         t, offsetof(struct fuse_cmdline_opts, p), v \
  35     }
  36
  37
  38 static const struct fuse_opt fuse_helper_opts[] = {
  39     FUSE_HELPER_OPT("-h", show_help),
  40     FUSE_HELPER_OPT("--help", show_help),
  41     FUSE_HELPER_OPT("-V", show_version),
  42     FUSE_HELPER_OPT("--version", show_version),
  43     FUSE_HELPER_OPT("-d", debug),
  44     FUSE_HELPER_OPT("debug", debug),
  45     FUSE_HELPER_OPT("-d", foreground),
  46     FUSE_HELPER_OPT("debug", foreground),
  47     FUSE_OPT_KEY("-d", FUSE_OPT_KEY_KEEP),
  48     FUSE_OPT_KEY("debug", FUSE_OPT_KEY_KEEP),
  49     FUSE_HELPER_OPT("-f", foreground),
  50     FUSE_HELPER_OPT_VALUE("--daemonize", foreground, 0),
  51     FUSE_HELPER_OPT("fsname=", nodefault_subtype),
  52     FUSE_OPT_KEY("fsname=", FUSE_OPT_KEY_KEEP),
  53     FUSE_HELPER_OPT("subtype=", nodefault_subtype),
  54     FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP),
  55     FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads),
  56     FUSE_OPT_END
  57 };
  58
  59 struct fuse_conn_info_opts {
  60     int atomic_o_trunc;
  61     int no_remote_posix_lock;
  62     int no_remote_flock;
  63     int splice_write;
  64     int splice_move;
  65     int splice_read;
  66     int no_splice_write;
  67     int no_splice_move;
  68     int no_splice_read;
  69     int auto_inval_data;
  70     int no_auto_inval_data;
  71     int no_readdirplus;
  72     int no_readdirplus_auto;
  73     int async_dio;
  74     int no_async_dio;
  75     int writeback_cache;
  76     int no_writeback_cache;
  77     int async_read;
  78     int sync_read;
  79     unsigned max_write;
  80     unsigned max_readahead;
  81     unsigned max_background;
  82     unsigned congestion_threshold;
  83     unsigned time_gran;
  84     int set_max_write;
  85     int set_max_readahead;
  86     int set_max_background;
  87     int set_congestion_threshold;
  88     int set_time_gran;
  89 };
  90
  91 #define CONN_OPTION(t, p, v)                          \
  92     {                                                 \
  93         t, offsetof(struct fuse_conn_info_opts, p), v \
  94     }
  95 static const struct fuse_opt conn_info_opt_spec[] = {
  96     CONN_OPTION("max_write=%u", max_write, 0),
  97     CONN_OPTION("max_write=", set_max_write, 1),
  98     CONN_OPTION("max_readahead=%u", max_readahead, 0),
  99     CONN_OPTION("max_readahead=", set_max_readahead, 1),
 100     CONN_OPTION("max_background=%u", max_background, 0),
 101     CONN_OPTION("max_background=", set_max_background, 1),
 102     CONN_OPTION("congestion_threshold=%u", congestion_threshold, 0),
 103     CONN_OPTION("congestion_threshold=", set_congestion_threshold, 1),
 104     CONN_OPTION("sync_read", sync_read, 1),
 105     CONN_OPTION("async_read", async_read, 1),
 106     CONN_OPTION("atomic_o_trunc", atomic_o_trunc, 1),
 107     CONN_OPTION("no_remote_lock", no_remote_posix_lock, 1),
 108     CONN_OPTION("no_remote_lock", no_remote_flock, 1),
 109     CONN_OPTION("no_remote_flock", no_remote_flock, 1),
 110     CONN_OPTION("no_remote_posix_lock", no_remote_posix_lock, 1),
 111     CONN_OPTION("splice_write", splice_write, 1),
 112     CONN_OPTION("no_splice_write", no_splice_write, 1),
 113     CONN_OPTION("splice_move", splice_move, 1),
 114     CONN_OPTION("no_splice_move", no_splice_move, 1),
 115     CONN_OPTION("splice_read", splice_read, 1),
 116     CONN_OPTION("no_splice_read", no_splice_read, 1),
 117     CONN_OPTION("auto_inval_data", auto_inval_data, 1),
 118     CONN_OPTION("no_auto_inval_data", no_auto_inval_data, 1),
 119     CONN_OPTION("readdirplus=no", no_readdirplus, 1),
 120     CONN_OPTION("readdirplus=yes", no_readdirplus, 0),
 121     CONN_OPTION("readdirplus=yes", no_readdirplus_auto, 1),
 122     CONN_OPTION("readdirplus=auto", no_readdirplus, 0),
 123     CONN_OPTION("readdirplus=auto", no_readdirplus_auto, 0),
 124     CONN_OPTION("async_dio", async_dio, 1),
 125     CONN_OPTION("no_async_dio", no_async_dio, 1),
 126     CONN_OPTION("writeback_cache", writeback_cache, 1),
 127     CONN_OPTION("no_writeback_cache", no_writeback_cache, 1),
 128     CONN_OPTION("time_gran=%u", time_gran, 0),
 129     CONN_OPTION("time_gran=", set_time_gran, 1),
 130     FUSE_OPT_END
 131 };
 132
 133
 134 void fuse_cmdline_help(void)
 135 {
 136     printf("    -h   --help                print help\n"
 137            "    -V   --version             print version\n"
 138            "    -d   -o debug              enable debug output (implies -f)\n"
 139            "    -f                         foreground operation\n"
 140            "    --daemonize                run in background\n"
 141            "    -o max_idle_threads        the maximum number of idle worker "
 142            "threads\n"
 143            "                               allowed (default: 10)\n");
 144 }
 145
 146 static int fuse_helper_opt_proc(void *data, const char *arg, int key,
 147                                 struct fuse_args *outargs)
 148 {
 149     (void)data;
 150     (void)outargs;
 151
 152     switch (key) {
 153     case FUSE_OPT_KEY_NONOPT:
 154         fuse_log(FUSE_LOG_ERR, "fuse: invalid argument `%s'\n", arg);
 155         return -1;
 156
 157     default:
 158         /* Pass through unknown options */
 159         return 1;
 160     }
 161 }
 162
 163 int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
 164 {
 165     memset(opts, 0, sizeof(struct fuse_cmdline_opts));
 166
 167     opts->max_idle_threads = 10;
 168     opts->foreground = 1;
 169
 170     if (fuse_opt_parse(args, opts, fuse_helper_opts, fuse_helper_opt_proc) ==
 171         -1) {
 172         return -1;
 173     }
 174
 175     return 0;
 176 }
 177
 178
 179 int fuse_daemonize(int foreground)
 180 {
 181     int ret = 0, rett;
 182     if (!foreground) {
 183         int nullfd;
 184         int waiter[2];
 185         char completed;
 186
 187         if (pipe(waiter)) {
 188             perror("fuse_daemonize: pipe");
 189             return -1;
 190         }
 191
 192         /*
 193          * demonize current process by forking it and killing the
 194          * parent.  This makes current process as a child of 'init'.
 195          */
 196         switch (fork()) {
 197         case -1:
 198             perror("fuse_daemonize: fork");
 199             return -1;
 200         case 0:
 201             break;
 202         default:
 203             _exit(read(waiter[0], &completed,
 204                        sizeof(completed) != sizeof(completed)));
 205         }
 206
 207         if (setsid() == -1) {
 208             perror("fuse_daemonize: setsid");
 209             return -1;
 210         }
 211
 212         ret = chdir("/");
 213
 214         nullfd = open("/dev/null", O_RDWR, 0);
 215         if (nullfd != -1) {
 216             rett = dup2(nullfd, 0);
 217             if (!ret) {
 218                 ret = rett;
 219             }
 220             rett = dup2(nullfd, 1);
 221             if (!ret) {
 222                 ret = rett;
 223             }
 224             rett = dup2(nullfd, 2);
 225             if (!ret) {
 226                 ret = rett;
 227             }
 228             if (nullfd > 2) {
 229                 close(nullfd);
 230             }
 231         }
 232
 233         /* Propagate completion of daemon initialization */
 234         completed = 1;
 235         rett = write(waiter[1], &completed, sizeof(completed));
 236         if (!ret) {
 237             ret = rett;
 238         }
 239         close(waiter[0]);
 240         close(waiter[1]);
 241     } else {
 242         ret = chdir("/");
 243     }
 244     return ret;
 245 }
 246
 247 void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
 248                                struct fuse_conn_info *conn)
 249 {
 250     if (opts->set_max_write) {
 251         conn->max_write = opts->max_write;
 252     }
 253     if (opts->set_max_background) {
 254         conn->max_background = opts->max_background;
 255     }
 256     if (opts->set_congestion_threshold) {
 257         conn->congestion_threshold = opts->congestion_threshold;
 258     }
 259     if (opts->set_time_gran) {
 260         conn->time_gran = opts->time_gran;
 261     }
 262     if (opts->set_max_readahead) {
 263         conn->max_readahead = opts->max_readahead;
 264     }
 265
 266 #define LL_ENABLE(cond, cap) \
 267     if (cond)                \
 268         conn->want |= (cap)
 269 #define LL_DISABLE(cond, cap) \
 270     if (cond)                 \
 271         conn->want &= ~(cap)
 272
 273     LL_ENABLE(opts->splice_read, FUSE_CAP_SPLICE_READ);
 274     LL_DISABLE(opts->no_splice_read, FUSE_CAP_SPLICE_READ);
 275
 276     LL_ENABLE(opts->splice_write, FUSE_CAP_SPLICE_WRITE);
 277     LL_DISABLE(opts->no_splice_write, FUSE_CAP_SPLICE_WRITE);
 278
 279     LL_ENABLE(opts->splice_move, FUSE_CAP_SPLICE_MOVE);
 280     LL_DISABLE(opts->no_splice_move, FUSE_CAP_SPLICE_MOVE);
 281
 282     LL_ENABLE(opts->auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
 283     LL_DISABLE(opts->no_auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
 284
 285     LL_DISABLE(opts->no_readdirplus, FUSE_CAP_READDIRPLUS);
 286     LL_DISABLE(opts->no_readdirplus_auto, FUSE_CAP_READDIRPLUS_AUTO);
 287
 288     LL_ENABLE(opts->async_dio, FUSE_CAP_ASYNC_DIO);
 289     LL_DISABLE(opts->no_async_dio, FUSE_CAP_ASYNC_DIO);
 290
 291     LL_ENABLE(opts->writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
 292     LL_DISABLE(opts->no_writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
 293
 294     LL_ENABLE(opts->async_read, FUSE_CAP_ASYNC_READ);
 295     LL_DISABLE(opts->sync_read, FUSE_CAP_ASYNC_READ);
 296
 297     LL_DISABLE(opts->no_remote_posix_lock, FUSE_CAP_POSIX_LOCKS);
 298     LL_DISABLE(opts->no_remote_flock, FUSE_CAP_FLOCK_LOCKS);
 299 }
 300
 301 struct fuse_conn_info_opts *fuse_parse_conn_info_opts(struct fuse_args *args)
 302 {
 303     struct fuse_conn_info_opts *opts;
 304
 305     opts = calloc(1, sizeof(struct fuse_conn_info_opts));
 306     if (opts == NULL) {
 307         fuse_log(FUSE_LOG_ERR, "calloc failed\n");
 308         return NULL;
 309     }
 310     if (fuse_opt_parse(args, opts, conn_info_opt_spec, NULL) == -1) {
 311         free(opts);
 312         return NULL;
 313     }
 314     return opts;
 315 }