server/internal.h

   1 /* nbdkit
   2  * Copyright (C) 2013-2020 Red Hat Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef NBDKIT_INTERNAL_H
  34 #define NBDKIT_INTERNAL_H
  35
  36 #include <stdbool.h>
  37 #include <stddef.h>
  38 #include <stdarg.h>
  39 #include <sys/socket.h>
  40 #include <pthread.h>
  41
  42 #define NBDKIT_API_VERSION 2
  43 #include "nbdkit-plugin.h"
  44 #include "nbdkit-filter.h"
  45 #include "cleanup.h"
  46 #include "nbd-protocol.h"
  47
  48 /* Define unlikely macro, but only for GCC.  These are used to move
  49  * debug and error handling code out of hot paths.
  50  */
  51 #if defined(__GNUC__)
  52 #define unlikely(x) __builtin_expect (!!(x), 0)
  53 #define if_verbose if (unlikely (verbose))
  54 #else
  55 #define unlikely(x) (x)
  56 #define if_verbose if (verbose)
  57 #endif
  58
  59 #ifdef __APPLE__
  60 #define UNIX_PATH_MAX 104
  61 #else
  62 #define UNIX_PATH_MAX 108
  63 #endif
  64
  65 #if HAVE_VALGRIND
  66 # include <valgrind.h>
  67 /* http://valgrind.org/docs/manual/faq.html#faq.unhelpful */
  68 # define DO_DLCLOSE !RUNNING_ON_VALGRIND
  69 #elif defined(__SANITIZE_ADDRESS__)
  70 # define DO_DLCLOSE 0
  71 #elif ENABLE_LIBFUZZER
  72 /* XXX This causes dlopen in the server to leak during fuzzing.
  73  * However it is necessary because of
  74  * https://bugs.llvm.org/show_bug.cgi?id=43917
  75  */
  76 # define DO_DLCLOSE 0
  77 #else
  78 # define DO_DLCLOSE 1
  79 #endif
  80
  81 #define container_of(ptr, type, member) ({                       \
  82       const typeof (((type *) 0)->member) *__mptr = (ptr);       \
  83       (type *) ((char *) __mptr - offsetof(type, member));       \
  84     })
  85
  86 /* Maximum read or write request that we will handle. */
  87 #define MAX_REQUEST_SIZE (64 * 1024 * 1024)
  88
  89 /* main.c */
  90 enum log_to {
  91   LOG_TO_DEFAULT,        /* --log not specified: log to stderr, unless
  92                             we forked into the background in which
  93                             case log to syslog */
  94   LOG_TO_STDERR,         /* --log=stderr forced on the command line */
  95   LOG_TO_SYSLOG,         /* --log=syslog forced on the command line */
  96   LOG_TO_NULL,           /* --log=null forced on the command line */
  97 };
  98
  99 extern struct debug_flag *debug_flags;
 100 extern const char *exportname;
 101 extern bool foreground;
 102 extern const char *ipaddr;
 103 extern enum log_to log_to;
 104 extern unsigned mask_handshake;
 105 extern bool newstyle;
 106 extern bool no_sr;
 107 extern const char *port;
 108 extern bool read_only;
 109 extern const char *run;
 110 extern bool listen_stdin;
 111 extern const char *selinux_label;
 112 extern unsigned threads;
 113 extern int tls;
 114 extern const char *tls_certificates_dir;
 115 extern const char *tls_psk;
 116 extern bool tls_verify_peer;
 117 extern char *unixsocket;
 118 extern const char *user, *group;
 119 extern bool verbose;
 120
 121 extern struct backend *backend;
 122 #define for_each_backend(b) for (b = backend; b != NULL; b = b->next)
 123
 124 /* quit.c */
 125 extern volatile int quit;
 126 extern int quit_fd;
 127 extern void set_up_quit_pipe (void);
 128 extern void close_quit_pipe (void);
 129 extern void handle_quit (int sig);
 130 extern void set_quit (void);
 131
 132 /* signals.c */
 133 extern void set_up_signals (void);
 134
 135 /* background.c */
 136 extern bool forked_into_background;
 137 extern void fork_into_background (void);
 138
 139 /* captive.c */
 140 extern void run_command (void);
 141
 142 /* socket-activation.c */
 143 #define FIRST_SOCKET_ACTIVATION_FD 3 /* defined by systemd ABI */
 144 extern unsigned int get_socket_activation (void);
 145
 146 /* usergroup.c */
 147 extern void change_user (void);
 148
 149 /* connections.c */
 150 struct connection;
 151
 152 /* Flags for connection_send_function */
 153 enum {
 154   SEND_MORE = 1, /* Hint to use MSG_MORE/corking to group send()s */
 155 };
 156
 157 typedef int (*connection_recv_function) (struct connection *,
 158                                          void *buf, size_t len)
 159   __attribute__((__nonnull__ (1, 2)));
 160 typedef int (*connection_send_function) (struct connection *,
 161                                          const void *buf, size_t len,
 162                                          int flags)
 163   __attribute__((__nonnull__ (1, 2)));
 164 typedef void (*connection_close_function) (struct connection *)
 165   __attribute__((__nonnull__ (1)));
 166
 167 enum {
 168   HANDLE_OPEN = 1,      /* Set if .open passed, so .close is needed */
 169   HANDLE_CONNECTED = 2, /* Set if .prepare passed, so .finalize is needed */
 170   HANDLE_FAILED = 4,    /* Set if .finalize failed */
 171 };
 172
 173 struct b_conn_handle {
 174   void *handle;
 175
 176   unsigned char state; /* Bitmask of HANDLE_* values */
 177
 178   uint64_t exportsize;
 179   int can_write;
 180   int can_flush;
 181   int is_rotational;
 182   int can_trim;
 183   int can_zero;
 184   int can_fast_zero;
 185   int can_fua;
 186   int can_multi_conn;
 187   int can_extents;
 188   int can_cache;
 189   int init_sparse;
 190   int init_zero;
 191 };
 192
 193 static inline void
 194 reset_b_conn_handle (struct b_conn_handle *h)
 195 {
 196   h->handle = NULL;
 197   h->state = 0;
 198   h->exportsize = -1;
 199   h->can_write = -1;
 200   h->can_flush = -1;
 201   h->is_rotational = -1;
 202   h->can_trim = -1;
 203   h->can_zero = -1;
 204   h->can_fast_zero = -1;
 205   h->can_fua = -1;
 206   h->can_multi_conn = -1;
 207   h->can_extents = -1;
 208   h->can_cache = -1;
 209   h->init_sparse = -1;
 210   h->init_zero = -1;
 211 }
 212
 213 struct connection {
 214   pthread_mutex_t request_lock;
 215   pthread_mutex_t read_lock;
 216   pthread_mutex_t write_lock;
 217   pthread_mutex_t status_lock;
 218   int status; /* 1 for more I/O with client, 0 for shutdown, -1 on error */
 219   int status_pipe[2]; /* track status changes via poll when nworkers > 1 */
 220   void *crypto_session;
 221   int nworkers;
 222
 223   struct b_conn_handle *handles;
 224   size_t nr_handles;
 225
 226   char exportname[NBD_MAX_STRING + 1];
 227   uint32_t exportnamelen;
 228   uint32_t cflags;
 229   uint16_t eflags;
 230   bool using_tls;
 231   bool structured_replies;
 232   bool meta_context_base_allocation;
 233
 234   int sockin, sockout;
 235   connection_recv_function recv;
 236   connection_send_function send;
 237   connection_close_function close;
 238 };
 239
 240 extern void handle_single_connection (int sockin, int sockout);
 241 extern int connection_get_status (struct connection *conn)
 242   __attribute__((__nonnull__ (1)));
 243 extern int connection_set_status (struct connection *conn, int value)
 244   __attribute__((__nonnull__ (1)));
 245
 246 /* protocol-handshake.c */
 247 extern int protocol_handshake (struct connection *conn)
 248   __attribute__((__nonnull__ (1)));
 249 extern int protocol_common_open (struct connection *conn,
 250                                  uint64_t *exportsize, uint16_t *flags)
 251   __attribute__((__nonnull__ (1, 2, 3)));
 252
 253 /* protocol-handshake-oldstyle.c */
 254 extern int protocol_handshake_oldstyle (struct connection *conn)
 255   __attribute__((__nonnull__ (1)));
 256
 257 /* protocol-handshake-newstyle.c */
 258 extern int protocol_handshake_newstyle (struct connection *conn)
 259   __attribute__((__nonnull__ (1)));
 260
 261 /* protocol.c */
 262 extern int protocol_recv_request_send_reply (struct connection *conn)
 263   __attribute__((__nonnull__ (1)));
 264
 265 /* The context ID of base:allocation.  As far as I can tell it doesn't
 266  * matter what this is as long as nbdkit always returns the same
 267  * number.
 268  */
 269 #define base_allocation_id 1
 270
 271 /* crypto.c */
 272 #define root_tls_certificates_dir sysconfdir "/pki/" PACKAGE_NAME
 273 extern void crypto_init (bool tls_set_on_cli);
 274 extern void crypto_free (void);
 275 extern int crypto_negotiate_tls (struct connection *conn,
 276                                  int sockin, int sockout)
 277   __attribute__((__nonnull__ (1)));
 278
 279 /* debug.c */
 280 #define debug(fs, ...)                                   \
 281   do {                                                   \
 282     if_verbose                                           \
 283       nbdkit_debug ((fs), ##__VA_ARGS__);                \
 284   } while (0)
 285
 286 /* debug-flags.c */
 287 extern void add_debug_flag (const char *arg);
 288 extern void apply_debug_flags (void *dl, const char *name);
 289 extern void free_debug_flags (void);
 290
 291 /* log-*.c */
 292 #if !HAVE_VFPRINTF_PERCENT_M
 293 #include <stdio.h>
 294 #define vfprintf nbdkit_vfprintf
 295 extern int nbdkit_vfprintf (FILE *f, const char *fmt, va_list args)
 296   __attribute__((__format__ (printf, 2, 0)));
 297 #endif
 298 extern void log_stderr_verror (const char *fs, va_list args)
 299   __attribute__((__format__ (printf, 1, 0)));
 300 extern void log_syslog_verror (const char *fs, va_list args)
 301   __attribute__((__format__ (printf, 1, 0)));
 302
 303 /* backend.c */
 304 struct backend {
 305   /* Next filter or plugin in the chain.  This is always NULL for
 306    * plugins and never NULL for filters.
 307    */
 308   struct backend *next;
 309
 310   /* A unique index used to fetch the handle from the connections
 311    * object.  The plugin (last in the chain) has index 0, and the
 312    * filters have index 1, 2, ... depending how "far" they are from
 313    * the plugin.
 314    */
 315   size_t i;
 316
 317   /* The type of backend: filter or plugin. */
 318   const char *type;
 319
 320   /* A copy of the backend name that survives a dlclose. */
 321   char *name;
 322
 323   /* The file the backend was loaded from. */
 324   char *filename;
 325
 326   /* The dlopen handle for the backend. */
 327   void *dl;
 328
 329   /* Backend callbacks. All are required. */
 330   void (*free) (struct backend *);
 331   int (*thread_model) (struct backend *);
 332   const char *(*plugin_name) (struct backend *);
 333   void (*usage) (struct backend *);
 334   const char *(*version) (struct backend *);
 335   void (*dump_fields) (struct backend *);
 336   void (*config) (struct backend *, const char *key, const char *value);
 337   void (*config_complete) (struct backend *);
 338   const char *(*magic_config_key) (struct backend *);
 339   int (*preconnect) (struct backend *, struct connection *conn, int readonly);
 340   void *(*open) (struct backend *, struct connection *conn, int readonly);
 341   int (*prepare) (struct backend *, struct connection *conn, void *handle,
 342                   int readonly);
 343   int (*finalize) (struct backend *, struct connection *conn, void *handle);
 344   void (*close) (struct backend *, struct connection *conn, void *handle);
 345
 346   int64_t (*get_size) (struct backend *, struct connection *conn, void *handle);
 347   int (*can_write) (struct backend *, struct connection *conn, void *handle);
 348   int (*can_flush) (struct backend *, struct connection *conn, void *handle);
 349   int (*is_rotational) (struct backend *, struct connection *conn,
 350                         void *handle);
 351   int (*can_trim) (struct backend *, struct connection *conn, void *handle);
 352   int (*can_zero) (struct backend *, struct connection *conn, void *handle);
 353   int (*can_fast_zero) (struct backend *, struct connection *conn,
 354                         void *handle);
 355   int (*can_extents) (struct backend *, struct connection *conn, void *handle);
 356   int (*can_fua) (struct backend *, struct connection *conn, void *handle);
 357   int (*can_multi_conn) (struct backend *, struct connection *conn,
 358                          void *handle);
 359   int (*can_cache) (struct backend *, struct connection *conn, void *handle);
 360   int (*init_sparse) (struct backend *, struct connection *conn, void *handle);
 361   int (*init_zero) (struct backend *, struct connection *conn, void *handle);
 362
 363   int (*pread) (struct backend *, struct connection *conn, void *handle,
 364                 void *buf, uint32_t count, uint64_t offset,
 365                 uint32_t flags, int *err);
 366   int (*pwrite) (struct backend *, struct connection *conn, void *handle,
 367                  const void *buf, uint32_t count, uint64_t offset,
 368                  uint32_t flags, int *err);
 369   int (*flush) (struct backend *, struct connection *conn, void *handle,
 370                 uint32_t flags, int *err);
 371   int (*trim) (struct backend *, struct connection *conn, void *handle,
 372                uint32_t count, uint64_t offset, uint32_t flags, int *err);
 373   int (*zero) (struct backend *, struct connection *conn, void *handle,
 374                uint32_t count, uint64_t offset, uint32_t flags, int *err);
 375   int (*extents) (struct backend *, struct connection *conn, void *handle,
 376                   uint32_t count, uint64_t offset, uint32_t flags,
 377                   struct nbdkit_extents *extents, int *err);
 378   int (*cache) (struct backend *, struct connection *conn, void *handle,
 379                 uint32_t count, uint64_t offset, uint32_t flags, int *err);
 380 };
 381
 382 extern void backend_init (struct backend *b, struct backend *next, size_t index,
 383                           const char *filename, void *dl, const char *type)
 384   __attribute__((__nonnull__ (1, 4, 5, 6)));
 385 extern void backend_load (struct backend *b, const char *name,
 386                           void (*load) (void))
 387   __attribute__((__nonnull__ (1 /* not 2 */)));
 388 extern void backend_unload (struct backend *b, void (*unload) (void))
 389   __attribute__((__nonnull__ (1)));
 390
 391 extern int backend_open (struct backend *b, struct connection *conn,
 392                          int readonly)
 393   __attribute__((__nonnull__ (1, 2)));
 394 extern int backend_prepare (struct backend *b, struct connection *conn)
 395   __attribute__((__nonnull__ (1, 2)));
 396 extern int backend_finalize (struct backend *b, struct connection *conn)
 397   __attribute__((__nonnull__ (1, 2)));
 398 extern void backend_close (struct backend *b, struct connection *conn)
 399   __attribute__((__nonnull__ (1, 2)));
 400 extern bool backend_valid_range (struct backend *b, struct connection *conn,
 401                                  uint64_t offset, uint32_t count)
 402   __attribute__((__nonnull__ (1, 2)));
 403
 404 extern int backend_reopen (struct backend *b, struct connection *conn,
 405                            int readonly)
 406   __attribute__((__nonnull__ (1, 2)));
 407 extern int64_t backend_get_size (struct backend *b, struct connection *conn)
 408   __attribute__((__nonnull__ (1, 2)));
 409 extern int backend_can_write (struct backend *b, struct connection *conn)
 410   __attribute__((__nonnull__ (1, 2)));
 411 extern int backend_can_flush (struct backend *b, struct connection *conn)
 412   __attribute__((__nonnull__ (1, 2)));
 413 extern int backend_is_rotational (struct backend *b, struct connection *conn)
 414   __attribute__((__nonnull__ (1, 2)));
 415 extern int backend_can_trim (struct backend *b, struct connection *conn)
 416   __attribute__((__nonnull__ (1, 2)));
 417 extern int backend_can_zero (struct backend *b, struct connection *conn)
 418   __attribute__((__nonnull__ (1, 2)));
 419 extern int backend_can_fast_zero (struct backend *b, struct connection *conn)
 420   __attribute__((__nonnull__ (1, 2)));
 421 extern int backend_can_extents (struct backend *b, struct connection *conn)
 422   __attribute__((__nonnull__ (1, 2)));
 423 extern int backend_can_fua (struct backend *b, struct connection *conn)
 424   __attribute__((__nonnull__ (1, 2)));
 425 extern int backend_can_multi_conn (struct backend *b, struct connection *conn)
 426   __attribute__((__nonnull__ (1, 2)));
 427 extern int backend_can_cache (struct backend *b, struct connection *conn)
 428   __attribute__((__nonnull__ (1, 2)));
 429 extern int backend_init_sparse (struct backend *b, struct connection *conn)
 430   __attribute__((__nonnull__ (1, 2)));
 431 extern int backend_init_zero (struct backend *b, struct connection *conn)
 432   __attribute__((__nonnull__ (1, 2)));
 433
 434 extern int backend_pread (struct backend *b, struct connection *conn,
 435                           void *buf, uint32_t count, uint64_t offset,
 436                           uint32_t flags, int *err)
 437   __attribute__((__nonnull__ (1, 2, 3, 7)));
 438 extern int backend_pwrite (struct backend *b, struct connection *conn,
 439                            const void *buf, uint32_t count, uint64_t offset,
 440                            uint32_t flags, int *err)
 441   __attribute__((__nonnull__ (1, 2, 3, 7)));
 442 extern int backend_flush (struct backend *b, struct connection *conn,
 443                           uint32_t flags, int *err)
 444   __attribute__((__nonnull__ (1, 2, 4)));
 445 extern int backend_trim (struct backend *b, struct connection *conn,
 446                          uint32_t count, uint64_t offset, uint32_t flags,
 447                          int *err)
 448   __attribute__((__nonnull__ (1, 2, 6)));
 449 extern int backend_zero (struct backend *b, struct connection *conn,
 450                          uint32_t count, uint64_t offset, uint32_t flags,
 451                          int *err)
 452   __attribute__((__nonnull__ (1, 2, 6)));
 453 extern int backend_extents (struct backend *b, struct connection *conn,
 454                             uint32_t count, uint64_t offset, uint32_t flags,
 455                             struct nbdkit_extents *extents, int *err)
 456   __attribute__((__nonnull__ (1, 2, 6, 7)));
 457 extern int backend_cache (struct backend *b, struct connection *conn,
 458                           uint32_t count, uint64_t offset,
 459                           uint32_t flags, int *err)
 460   __attribute__((__nonnull__ (1, 2, 6)));
 461
 462 /* plugins.c */
 463 extern struct backend *plugin_register (size_t index, const char *filename,
 464                                         void *dl, struct nbdkit_plugin *(*plugin_init) (void))
 465   __attribute__((__nonnull__ (2, 3, 4)));
 466
 467 /* filters.c */
 468 extern struct backend *filter_register (struct backend *next, size_t index,
 469                                         const char *filename, void *dl,
 470                                         struct nbdkit_filter *(*filter_init) (void))
 471   __attribute__((__nonnull__ (1, 3, 4, 5)));
 472
 473 /* locks.c */
 474 extern void lock_init_thread_model (void);
 475 extern const char *name_of_thread_model (int model);
 476 extern void lock_connection (void);
 477 extern void unlock_connection (void);
 478 extern void lock_request (struct connection *conn);
 479 extern void unlock_request (struct connection *conn);
 480 extern void lock_unload (void);
 481 extern void unlock_unload (void);
 482
 483 /* sockets.c */
 484 extern int *bind_unix_socket (size_t *)
 485   __attribute__((__nonnull__ (1)));
 486 extern int *bind_tcpip_socket (size_t *)
 487   __attribute__((__nonnull__ (1)));
 488 extern int *bind_vsock (size_t *)
 489   __attribute__((__nonnull__ (1)));
 490 extern void accept_incoming_connections (int *socks, size_t nr_socks)
 491   __attribute__((__nonnull__ (1)));
 492
 493 /* threadlocal.c */
 494 extern void threadlocal_init (void);
 495 extern void threadlocal_new_server_thread (void);
 496 extern void threadlocal_set_name (const char *name)
 497   __attribute__((__nonnull__ (1)));
 498 extern const char *threadlocal_get_name (void);
 499 extern void threadlocal_set_instance_num (size_t instance_num);
 500 extern size_t threadlocal_get_instance_num (void);
 501 extern void threadlocal_set_error (int err);
 502 extern int threadlocal_get_error (void);
 503 extern void *threadlocal_buffer (size_t size);
 504 extern void threadlocal_set_conn (struct connection *conn);
 505 extern struct connection *threadlocal_get_conn (void);
 506
 507 /* Declare program_name. */
 508 #if HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME == 1
 509 #include <errno.h>
 510 #define program_name program_invocation_short_name
 511 #else
 512 #define program_name "nbdkit"
 513 #endif
 514
 515 #endif /* NBDKIT_INTERNAL_H */