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 log_level=<level>       log level, default to \"info\"\n"
 149            "                               level could be one of \"debug, "
 150            "info, warn, err\"\n"
 151            "    -o max_idle_threads        the maximum number of idle worker "
 152            "threads\n"
 153            "                               allowed (default: 10)\n"
 154            "    -o norace                  disable racy fallback\n"
 155            "                               default: false\n"
 156            "    -o readdirplus|no_readdirplus\n"
 157            "                               enable/disable readirplus\n"
 158            "                               default: readdirplus except with "
 159            "cache=never\n"
 160           );
 161 }
 162
 163 static int fuse_helper_opt_proc(void *data, const char *arg, int key,
 164                                 struct fuse_args *outargs)
 165 {
 166     (void)data;
 167     (void)outargs;
 168
 169     switch (key) {
 170     case FUSE_OPT_KEY_NONOPT:
 171         fuse_log(FUSE_LOG_ERR, "fuse: invalid argument `%s'\n", arg);
 172         return -1;
 173
 174     default:
 175         /* Pass through unknown options */
 176         return 1;
 177     }
 178 }
 179
 180 int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
 181 {
 182     memset(opts, 0, sizeof(struct fuse_cmdline_opts));
 183
 184     opts->max_idle_threads = 10;
 185     opts->foreground = 1;
 186
 187     if (fuse_opt_parse(args, opts, fuse_helper_opts, fuse_helper_opt_proc) ==
 188         -1) {
 189         return -1;
 190     }
 191
 192     return 0;
 193 }
 194
 195
 196 int fuse_daemonize(int foreground)
 197 {
 198     int ret = 0, rett;
 199     if (!foreground) {
 200         int nullfd;
 201         int waiter[2];
 202         char completed;
 203
 204         if (pipe(waiter)) {
 205             perror("fuse_daemonize: pipe");
 206             return -1;
 207         }
 208
 209         /*
 210          * demonize current process by forking it and killing the
 211          * parent.  This makes current process as a child of 'init'.
 212          */
 213         switch (fork()) {
 214         case -1:
 215             perror("fuse_daemonize: fork");
 216             return -1;
 217         case 0:
 218             break;
 219         default:
 220             _exit(read(waiter[0], &completed,
 221                        sizeof(completed) != sizeof(completed)));
 222         }
 223
 224         if (setsid() == -1) {
 225             perror("fuse_daemonize: setsid");
 226             return -1;
 227         }
 228
 229         ret = chdir("/");
 230
 231         nullfd = open("/dev/null", O_RDWR, 0);
 232         if (nullfd != -1) {
 233             rett = dup2(nullfd, 0);
 234             if (!ret) {
 235                 ret = rett;
 236             }
 237             rett = dup2(nullfd, 1);
 238             if (!ret) {
 239                 ret = rett;
 240             }
 241             rett = dup2(nullfd, 2);
 242             if (!ret) {
 243                 ret = rett;
 244             }
 245             if (nullfd > 2) {
 246                 close(nullfd);
 247             }
 248         }
 249
 250         /* Propagate completion of daemon initialization */
 251         completed = 1;
 252         rett = write(waiter[1], &completed, sizeof(completed));
 253         if (!ret) {
 254             ret = rett;
 255         }
 256         close(waiter[0]);
 257         close(waiter[1]);
 258     } else {
 259         ret = chdir("/");
 260     }
 261     return ret;
 262 }
 263
 264 void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
 265                                struct fuse_conn_info *conn)
 266 {
 267     if (opts->set_max_write) {
 268         conn->max_write = opts->max_write;
 269     }
 270     if (opts->set_max_background) {
 271         conn->max_background = opts->max_background;
 272     }
 273     if (opts->set_congestion_threshold) {
 274         conn->congestion_threshold = opts->congestion_threshold;
 275     }
 276     if (opts->set_time_gran) {
 277         conn->time_gran = opts->time_gran;
 278     }
 279     if (opts->set_max_readahead) {
 280         conn->max_readahead = opts->max_readahead;
 281     }
 282
 283 #define LL_ENABLE(cond, cap) \
 284     if (cond)                \
 285         conn->want |= (cap)
 286 #define LL_DISABLE(cond, cap) \
 287     if (cond)                 \
 288         conn->want &= ~(cap)
 289
 290     LL_ENABLE(opts->splice_read, FUSE_CAP_SPLICE_READ);
 291     LL_DISABLE(opts->no_splice_read, FUSE_CAP_SPLICE_READ);
 292
 293     LL_ENABLE(opts->splice_write, FUSE_CAP_SPLICE_WRITE);
 294     LL_DISABLE(opts->no_splice_write, FUSE_CAP_SPLICE_WRITE);
 295
 296     LL_ENABLE(opts->splice_move, FUSE_CAP_SPLICE_MOVE);
 297     LL_DISABLE(opts->no_splice_move, FUSE_CAP_SPLICE_MOVE);
 298
 299     LL_ENABLE(opts->auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
 300     LL_DISABLE(opts->no_auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
 301
 302     LL_DISABLE(opts->no_readdirplus, FUSE_CAP_READDIRPLUS);
 303     LL_DISABLE(opts->no_readdirplus_auto, FUSE_CAP_READDIRPLUS_AUTO);
 304
 305     LL_ENABLE(opts->async_dio, FUSE_CAP_ASYNC_DIO);
 306     LL_DISABLE(opts->no_async_dio, FUSE_CAP_ASYNC_DIO);
 307
 308     LL_ENABLE(opts->writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
 309     LL_DISABLE(opts->no_writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
 310
 311     LL_ENABLE(opts->async_read, FUSE_CAP_ASYNC_READ);
 312     LL_DISABLE(opts->sync_read, FUSE_CAP_ASYNC_READ);
 313
 314     LL_DISABLE(opts->no_remote_posix_lock, FUSE_CAP_POSIX_LOCKS);
 315     LL_DISABLE(opts->no_remote_flock, FUSE_CAP_FLOCK_LOCKS);
 316 }
 317
 318 struct fuse_conn_info_opts *fuse_parse_conn_info_opts(struct fuse_args *args)
 319 {
 320     struct fuse_conn_info_opts *opts;
 321
 322     opts = calloc(1, sizeof(struct fuse_conn_info_opts));
 323     if (opts == NULL) {
 324         fuse_log(FUSE_LOG_ERR, "calloc failed\n");
 325         return NULL;
 326     }
 327     if (fuse_opt_parse(args, opts, conn_info_opt_spec, NULL) == -1) {
 328         free(opts);
 329         return NULL;
 330     }
 331     return opts;
 332 }