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 static const struct fuse_opt fuse_helper_opts[] = {
  38     FUSE_HELPER_OPT("-h", show_help),
  39     FUSE_HELPER_OPT("--help", show_help),
  40     FUSE_HELPER_OPT("-V", show_version),
  41     FUSE_HELPER_OPT("--version", show_version),
  42     FUSE_HELPER_OPT("--print-capabilities", print_capabilities),
  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_HELPER_OPT("--syslog", syslog),
  57     FUSE_HELPER_OPT_VALUE("log_level=debug", log_level, FUSE_LOG_DEBUG),
  58     FUSE_HELPER_OPT_VALUE("log_level=info", log_level, FUSE_LOG_INFO),
  59     FUSE_HELPER_OPT_VALUE("log_level=warn", log_level, FUSE_LOG_WARNING),
  60     FUSE_HELPER_OPT_VALUE("log_level=err", log_level, FUSE_LOG_ERR),
  61     FUSE_OPT_END
  62 };
  63
  64 struct fuse_conn_info_opts {
  65     int atomic_o_trunc;
  66     int no_remote_posix_lock;
  67     int no_remote_flock;
  68     int splice_write;
  69     int splice_move;
  70     int splice_read;
  71     int no_splice_write;
  72     int no_splice_move;
  73     int no_splice_read;
  74     int auto_inval_data;
  75     int no_auto_inval_data;
  76     int no_readdirplus;
  77     int no_readdirplus_auto;
  78     int async_dio;
  79     int no_async_dio;
  80     int writeback_cache;
  81     int no_writeback_cache;
  82     int async_read;
  83     int sync_read;
  84     unsigned max_write;
  85     unsigned max_readahead;
  86     unsigned max_background;
  87     unsigned congestion_threshold;
  88     unsigned time_gran;
  89     int set_max_write;
  90     int set_max_readahead;
  91     int set_max_background;
  92     int set_congestion_threshold;
  93     int set_time_gran;
  94 };
  95
  96 #define CONN_OPTION(t, p, v)                          \
  97     {                                                 \
  98         t, offsetof(struct fuse_conn_info_opts, p), v \
  99     }
 100 static const struct fuse_opt conn_info_opt_spec[] = {
 101     CONN_OPTION("max_write=%u", max_write, 0),
 102     CONN_OPTION("max_write=", set_max_write, 1),
 103     CONN_OPTION("max_readahead=%u", max_readahead, 0),
 104     CONN_OPTION("max_readahead=", set_max_readahead, 1),
 105     CONN_OPTION("max_background=%u", max_background, 0),
 106     CONN_OPTION("max_background=", set_max_background, 1),
 107     CONN_OPTION("congestion_threshold=%u", congestion_threshold, 0),
 108     CONN_OPTION("congestion_threshold=", set_congestion_threshold, 1),
 109     CONN_OPTION("sync_read", sync_read, 1),
 110     CONN_OPTION("async_read", async_read, 1),
 111     CONN_OPTION("atomic_o_trunc", atomic_o_trunc, 1),
 112     CONN_OPTION("no_remote_lock", no_remote_posix_lock, 1),
 113     CONN_OPTION("no_remote_lock", no_remote_flock, 1),
 114     CONN_OPTION("no_remote_flock", no_remote_flock, 1),
 115     CONN_OPTION("no_remote_posix_lock", no_remote_posix_lock, 1),
 116     CONN_OPTION("splice_write", splice_write, 1),
 117     CONN_OPTION("no_splice_write", no_splice_write, 1),
 118     CONN_OPTION("splice_move", splice_move, 1),
 119     CONN_OPTION("no_splice_move", no_splice_move, 1),
 120     CONN_OPTION("splice_read", splice_read, 1),
 121     CONN_OPTION("no_splice_read", no_splice_read, 1),
 122     CONN_OPTION("auto_inval_data", auto_inval_data, 1),
 123     CONN_OPTION("no_auto_inval_data", no_auto_inval_data, 1),
 124     CONN_OPTION("readdirplus=no", no_readdirplus, 1),
 125     CONN_OPTION("readdirplus=yes", no_readdirplus, 0),
 126     CONN_OPTION("readdirplus=yes", no_readdirplus_auto, 1),
 127     CONN_OPTION("readdirplus=auto", no_readdirplus, 0),
 128     CONN_OPTION("readdirplus=auto", no_readdirplus_auto, 0),
 129     CONN_OPTION("async_dio", async_dio, 1),
 130     CONN_OPTION("no_async_dio", no_async_dio, 1),
 131     CONN_OPTION("writeback_cache", writeback_cache, 1),
 132     CONN_OPTION("no_writeback_cache", no_writeback_cache, 1),
 133     CONN_OPTION("time_gran=%u", time_gran, 0),
 134     CONN_OPTION("time_gran=", set_time_gran, 1),
 135     FUSE_OPT_END
 136 };
 137
 138
 139 void fuse_cmdline_help(void)
 140 {
 141     printf("    -h   --help                print help\n"
 142            "    -V   --version             print version\n"
 143            "    --print-capabilities       print vhost-user.json\n"
 144            "    -d   -o debug              enable debug output (implies -f)\n"
 145            "    --syslog                   log to syslog (default stderr)\n"
 146            "    -f                         foreground operation\n"
 147            "    --daemonize                run in background\n"
 148            "    -o cache=<mode>            cache mode. could be one of \"auto, "
 149            "always, none\"\n"
 150            "                               default: auto\n"
 151            "    -o flock|no_flock          enable/disable flock\n"
 152            "                               default: no_flock\n"
 153            "    -o log_level=<level>       log level, default to \"info\"\n"
 154            "                               level could be one of \"debug, "
 155            "info, warn, err\"\n"
 156            "    -o max_idle_threads        the maximum number of idle worker "
 157            "threads\n"
 158            "                               allowed (default: 10)\n"
 159            "    -o norace                  disable racy fallback\n"
 160            "                               default: false\n"
 161            "    -o posix_lock|no_posix_lock\n"
 162            "                               enable/disable remote posix lock\n"
 163            "                               default: posix_lock\n"
 164            "    -o readdirplus|no_readdirplus\n"
 165            "                               enable/disable readirplus\n"
 166            "                               default: readdirplus except with "
 167            "cache=none\n"
 168            "    -o timeout=<number>        I/O timeout (seconds)\n"
 169            "                               default: depends on cache= option.\n"
 170            "    -o writeback|no_writeback  enable/disable writeback cache\n"
 171            "                               default: no_writeback\n"
 172            "    -o xattr|no_xattr          enable/disable xattr\n"
 173            "                               default: no_xattr\n"
 174            );
 175 }
 176
 177 static int fuse_helper_opt_proc(void *data, const char *arg, int key,
 178                                 struct fuse_args *outargs)
 179 {
 180     (void)data;
 181     (void)outargs;
 182
 183     switch (key) {
 184     case FUSE_OPT_KEY_NONOPT:
 185         fuse_log(FUSE_LOG_ERR, "fuse: invalid argument `%s'\n", arg);
 186         return -1;
 187
 188     default:
 189         /* Pass through unknown options */
 190         return 1;
 191     }
 192 }
 193
 194 int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
 195 {
 196     memset(opts, 0, sizeof(struct fuse_cmdline_opts));
 197
 198     opts->max_idle_threads = 10;
 199     opts->foreground = 1;
 200
 201     if (fuse_opt_parse(args, opts, fuse_helper_opts, fuse_helper_opt_proc) ==
 202         -1) {
 203         return -1;
 204     }
 205
 206     return 0;
 207 }
 208
 209
 210 int fuse_daemonize(int foreground)
 211 {
 212     int ret = 0, rett;
 213     if (!foreground) {
 214         int nullfd;
 215         int waiter[2];
 216         char completed;
 217
 218         if (pipe(waiter)) {
 219             fuse_log(FUSE_LOG_ERR, "fuse_daemonize: pipe: %s\n",
 220                      strerror(errno));
 221             return -1;
 222         }
 223
 224         /*
 225          * demonize current process by forking it and killing the
 226          * parent.  This makes current process as a child of 'init'.
 227          */
 228         switch (fork()) {
 229         case -1:
 230             fuse_log(FUSE_LOG_ERR, "fuse_daemonize: fork: %s\n",
 231                      strerror(errno));
 232             return -1;
 233         case 0:
 234             break;
 235         default:
 236             _exit(read(waiter[0], &completed,
 237                        sizeof(completed) != sizeof(completed)));
 238         }
 239
 240         if (setsid() == -1) {
 241             fuse_log(FUSE_LOG_ERR, "fuse_daemonize: setsid: %s\n",
 242                      strerror(errno));
 243             return -1;
 244         }
 245
 246         ret = chdir("/");
 247
 248         nullfd = open("/dev/null", O_RDWR, 0);
 249         if (nullfd != -1) {
 250             rett = dup2(nullfd, 0);
 251             if (!ret) {
 252                 ret = rett;
 253             }
 254             rett = dup2(nullfd, 1);
 255             if (!ret) {
 256                 ret = rett;
 257             }
 258             rett = dup2(nullfd, 2);
 259             if (!ret) {
 260                 ret = rett;
 261             }
 262             if (nullfd > 2) {
 263                 close(nullfd);
 264             }
 265         }
 266
 267         /* Propagate completion of daemon initialization */
 268         completed = 1;
 269         rett = write(waiter[1], &completed, sizeof(completed));
 270         if (!ret) {
 271             ret = rett;
 272         }
 273         close(waiter[0]);
 274         close(waiter[1]);
 275     } else {
 276         ret = chdir("/");
 277     }
 278     return ret;
 279 }
 280
 281 void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
 282                                struct fuse_conn_info *conn)
 283 {
 284     if (opts->set_max_write) {
 285         conn->max_write = opts->max_write;
 286     }
 287     if (opts->set_max_background) {
 288         conn->max_background = opts->max_background;
 289     }
 290     if (opts->set_congestion_threshold) {
 291         conn->congestion_threshold = opts->congestion_threshold;
 292     }
 293     if (opts->set_time_gran) {
 294         conn->time_gran = opts->time_gran;
 295     }
 296     if (opts->set_max_readahead) {
 297         conn->max_readahead = opts->max_readahead;
 298     }
 299
 300 #define LL_ENABLE(cond, cap) \
 301     if (cond)                \
 302         conn->want |= (cap)
 303 #define LL_DISABLE(cond, cap) \
 304     if (cond)                 \
 305         conn->want &= ~(cap)
 306
 307     LL_ENABLE(opts->splice_read, FUSE_CAP_SPLICE_READ);
 308     LL_DISABLE(opts->no_splice_read, FUSE_CAP_SPLICE_READ);
 309
 310     LL_ENABLE(opts->splice_write, FUSE_CAP_SPLICE_WRITE);
 311     LL_DISABLE(opts->no_splice_write, FUSE_CAP_SPLICE_WRITE);
 312
 313     LL_ENABLE(opts->splice_move, FUSE_CAP_SPLICE_MOVE);
 314     LL_DISABLE(opts->no_splice_move, FUSE_CAP_SPLICE_MOVE);
 315
 316     LL_ENABLE(opts->auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
 317     LL_DISABLE(opts->no_auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
 318
 319     LL_DISABLE(opts->no_readdirplus, FUSE_CAP_READDIRPLUS);
 320     LL_DISABLE(opts->no_readdirplus_auto, FUSE_CAP_READDIRPLUS_AUTO);
 321
 322     LL_ENABLE(opts->async_dio, FUSE_CAP_ASYNC_DIO);
 323     LL_DISABLE(opts->no_async_dio, FUSE_CAP_ASYNC_DIO);
 324
 325     LL_ENABLE(opts->writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
 326     LL_DISABLE(opts->no_writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
 327
 328     LL_ENABLE(opts->async_read, FUSE_CAP_ASYNC_READ);
 329     LL_DISABLE(opts->sync_read, FUSE_CAP_ASYNC_READ);
 330
 331     LL_DISABLE(opts->no_remote_posix_lock, FUSE_CAP_POSIX_LOCKS);
 332     LL_DISABLE(opts->no_remote_flock, FUSE_CAP_FLOCK_LOCKS);
 333 }
 334
 335 struct fuse_conn_info_opts *fuse_parse_conn_info_opts(struct fuse_args *args)
 336 {
 337     struct fuse_conn_info_opts *opts;
 338
 339     opts = calloc(1, sizeof(struct fuse_conn_info_opts));
 340     if (opts == NULL) {
 341         fuse_log(FUSE_LOG_ERR, "calloc failed\n");
 342         return NULL;
 343     }
 344     if (fuse_opt_parse(args, opts, conn_info_opt_spec, NULL) == -1) {
 345         free(opts);
 346         return NULL;
 347     }
 348     return opts;
 349 }