src/common/util.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2013, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 /**
   7  * \file util.h
   8  * \brief Headers for util.c
   9  **/
  10
  11 #ifndef TOR_UTIL_H
  12 #define TOR_UTIL_H
  13
  14 #include "orconfig.h"
  15 #include "torint.h"
  16 #include "compat.h"
  17 #include "di_ops.h"
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #ifdef _WIN32
  21 /* for the correct alias to struct stat */
  22 #include <sys/stat.h>
  23 #endif
  24
  25 #ifndef O_BINARY
  26 #define O_BINARY 0
  27 #endif
  28 #ifndef O_TEXT
  29 #define O_TEXT 0
  30 #endif
  31
  32 /* Replace assert() with a variant that sends failures to the log before
  33  * calling assert() normally.
  34  */
  35 #ifdef NDEBUG
  36 /* Nobody should ever want to build with NDEBUG set.  99% of our asserts will
  37  * be outside the critical path anyway, so it's silly to disable bug-checking
  38  * throughout the entire program just because a few asserts are slowing you
  39  * down.  Profile, optimize the critical path, and keep debugging on.
  40  *
  41  * And I'm not just saying that because some of our asserts check
  42  * security-critical properties.
  43  */
  44 #error "Sorry; we don't support building with NDEBUG."
  45 #endif
  46
  47 /** Like assert(3), but send assertion failures to the log as well as to
  48  * stderr. */
  49 #define tor_assert(expr) STMT_BEGIN                                     \
  50     if (PREDICT_UNLIKELY(!(expr))) {                                    \
  51       log_err(LD_BUG, "%s:%d: %s: Assertion %s failed; aborting.",      \
  52           SHORT_FILE__, __LINE__, __func__, #expr);                     \
  53       fprintf(stderr,"%s:%d %s: Assertion %s failed; aborting.\n",      \
  54               SHORT_FILE__, __LINE__, __func__, #expr);                 \
  55       abort();                                                          \
  56     } STMT_END
  57
  58 /* If we're building with dmalloc, we want all of our memory allocation
  59  * functions to take an extra file/line pair of arguments.  If not, not.
  60  * We define DMALLOC_PARAMS to the extra parameters to insert in the
  61  * function prototypes, and DMALLOC_ARGS to the extra arguments to add
  62  * to calls. */
  63 #ifdef USE_DMALLOC
  64 #define DMALLOC_PARAMS , const char *file, const int line
  65 #define DMALLOC_ARGS , SHORT_FILE__, __LINE__
  66 #else
  67 #define DMALLOC_PARAMS
  68 #define DMALLOC_ARGS
  69 #endif
  70
  71 /** Define this if you want Tor to crash when any problem comes up,
  72  * so you can get a coredump and track things down. */
  73 // #define tor_fragile_assert() tor_assert(0)
  74 #define tor_fragile_assert()
  75
  76 /* Memory management */
  77 void *tor_malloc_(size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  78 void *tor_malloc_zero_(size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  79 void *tor_calloc_(size_t nmemb, size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  80 void *tor_realloc_(void *ptr, size_t size DMALLOC_PARAMS);
  81 char *tor_strdup_(const char *s DMALLOC_PARAMS) ATTR_MALLOC ATTR_NONNULL((1));
  82 char *tor_strndup_(const char *s, size_t n DMALLOC_PARAMS)
  83   ATTR_MALLOC ATTR_NONNULL((1));
  84 void *tor_memdup_(const void *mem, size_t len DMALLOC_PARAMS)
  85   ATTR_MALLOC ATTR_NONNULL((1));
  86 void *tor_memdup_nulterm_(const void *mem, size_t len DMALLOC_PARAMS)
  87   ATTR_MALLOC ATTR_NONNULL((1));
  88 void tor_free_(void *mem);
  89 #ifdef USE_DMALLOC
  90 extern int dmalloc_free(const char *file, const int line, void *pnt,
  91                         const int func_id);
  92 #define tor_free(p) STMT_BEGIN \
  93     if (PREDICT_LIKELY((p)!=NULL)) {                \
  94       dmalloc_free(SHORT_FILE__, __LINE__, (p), 0); \
  95       (p)=NULL;                                     \
  96     }                                               \
  97   STMT_END
  98 #else
  99 /** Release memory allocated by tor_malloc, tor_realloc, tor_strdup, etc.
 100  * Unlike the free() function, tor_free() will still work on NULL pointers,
 101  * and it sets the pointer value to NULL after freeing it.
 102  *
 103  * This is a macro.  If you need a function pointer to release memory from
 104  * tor_malloc(), use tor_free_().
 105  */
 106 #define tor_free(p) STMT_BEGIN                                 \
 107     if (PREDICT_LIKELY((p)!=NULL)) {                           \
 108       free(p);                                                 \
 109       (p)=NULL;                                                \
 110     }                                                          \
 111   STMT_END
 112 #endif
 113
 114 #define tor_malloc(size)       tor_malloc_(size DMALLOC_ARGS)
 115 #define tor_malloc_zero(size)  tor_malloc_zero_(size DMALLOC_ARGS)
 116 #define tor_calloc(nmemb,size) tor_calloc_(nmemb, size DMALLOC_ARGS)
 117 #define tor_realloc(ptr, size) tor_realloc_(ptr, size DMALLOC_ARGS)
 118 #define tor_strdup(s)          tor_strdup_(s DMALLOC_ARGS)
 119 #define tor_strndup(s, n)      tor_strndup_(s, n DMALLOC_ARGS)
 120 #define tor_memdup(s, n)       tor_memdup_(s, n DMALLOC_ARGS)
 121 #define tor_memdup_nulterm(s, n)       tor_memdup_nulterm_(s, n DMALLOC_ARGS)
 122
 123 void tor_log_mallinfo(int severity);
 124
 125 /** Return the offset of <b>member</b> within the type <b>tp</b>, in bytes */
 126 #if defined(__GNUC__) && __GNUC__ > 3
 127 #define STRUCT_OFFSET(tp, member) __builtin_offsetof(tp, member)
 128 #else
 129  #define STRUCT_OFFSET(tp, member) \
 130    ((off_t) (((char*)&((tp*)0)->member)-(char*)0))
 131 #endif
 132
 133 /** Macro: yield a pointer to the field at position <b>off</b> within the
 134  * structure <b>st</b>.  Example:
 135  * <pre>
 136  *   struct a { int foo; int bar; } x;
 137  *   off_t bar_offset = STRUCT_OFFSET(struct a, bar);
 138  *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);
 139  *   *bar_p = 3;
 140  * </pre>
 141  */
 142 #define STRUCT_VAR_P(st, off) ((void*) ( ((char*)(st)) + (off) ) )
 143
 144 /** Macro: yield a pointer to an enclosing structure given a pointer to
 145  * a substructure at offset <b>off</b>. Example:
 146  * <pre>
 147  *   struct base { ... };
 148  *   struct subtype { int x; struct base b; } x;
 149  *   struct base *bp = &x.base;
 150  *   struct *sp = SUBTYPE_P(bp, struct subtype, b);
 151  * </pre>
 152  */
 153 #define SUBTYPE_P(p, subtype, basemember) \
 154   ((void*) ( ((char*)(p)) - STRUCT_OFFSET(subtype, basemember) ))
 155
 156 /* Logic */
 157 /** Macro: true if two values have the same boolean value. */
 158 #define bool_eq(a,b) (!(a)==!(b))
 159 /** Macro: true if two values have different boolean values. */
 160 #define bool_neq(a,b) (!(a)!=!(b))
 161
 162 /* Math functions */
 163 double tor_mathlog(double d) ATTR_CONST;
 164 long tor_lround(double d) ATTR_CONST;
 165 int64_t tor_llround(double d) ATTR_CONST;
 166 int tor_log2(uint64_t u64) ATTR_CONST;
 167 uint64_t round_to_power_of_2(uint64_t u64);
 168 unsigned round_to_next_multiple_of(unsigned number, unsigned divisor);
 169 uint32_t round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor);
 170 uint64_t round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor);
 171 int n_bits_set_u8(uint8_t v);
 172
 173 /* Compute the CEIL of <b>a</b> divided by <b>b</b>, for nonnegative <b>a</b>
 174  * and positive <b>b</b>.  Works on integer types only. Not defined if a+b can
 175  * overflow. */
 176 #define CEIL_DIV(a,b) (((a)+(b)-1)/(b))
 177
 178 /* Return <b>v</b> if it's between <b>min</b> and <b>max</b>.  Otherwise
 179  * return <b>min</b> if <b>v</b> is smaller than <b>min</b>, or <b>max</b> if
 180  * <b>b</b> is larger than <b>max</b>.
 181  *
 182  * Requires that <b>min</b> is no more than <b>max</b>. May evaluate any of
 183  * its arguments more than once! */
 184 #define CLAMP(min,v,max)                        \
 185   ( ((v) < (min)) ? (min) :                     \
 186     ((v) > (max)) ? (max) :                     \
 187     (v) )
 188
 189 /* String manipulation */
 190
 191 /** Allowable characters in a hexadecimal string. */
 192 #define HEX_CHARACTERS "0123456789ABCDEFabcdef"
 193 void tor_strlower(char *s) ATTR_NONNULL((1));
 194 void tor_strupper(char *s) ATTR_NONNULL((1));
 195 int tor_strisprint(const char *s) ATTR_NONNULL((1));
 196 int tor_strisnonupper(const char *s) ATTR_NONNULL((1));
 197 int strcmp_opt(const char *s1, const char *s2);
 198 int strcmpstart(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 199 int strcmp_len(const char *s1, const char *s2, size_t len) ATTR_NONNULL((1,2));
 200 int strcasecmpstart(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 201 int strcmpend(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 202 int strcasecmpend(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 203 int fast_memcmpstart(const void *mem, size_t memlen, const char *prefix);
 204 void tor_strclear(char *s);
 205
 206 void tor_strstrip(char *s, const char *strip) ATTR_NONNULL((1,2));
 207 long tor_parse_long(const char *s, int base, long min,
 208                     long max, int *ok, char **next);
 209 unsigned long tor_parse_ulong(const char *s, int base, unsigned long min,
 210                               unsigned long max, int *ok, char **next);
 211 double tor_parse_double(const char *s, double min, double max, int *ok,
 212                         char **next);
 213 uint64_t tor_parse_uint64(const char *s, int base, uint64_t min,
 214                          uint64_t max, int *ok, char **next);
 215 const char *hex_str(const char *from, size_t fromlen) ATTR_NONNULL((1));
 216 const char *eat_whitespace(const char *s);
 217 const char *eat_whitespace_eos(const char *s, const char *eos);
 218 const char *eat_whitespace_no_nl(const char *s);
 219 const char *eat_whitespace_eos_no_nl(const char *s, const char *eos);
 220 const char *find_whitespace(const char *s);
 221 const char *find_whitespace_eos(const char *s, const char *eos);
 222 const char *find_str_at_start_of_line(const char *haystack,
 223                                       const char *needle);
 224 int string_is_C_identifier(const char *string);
 225
 226 int tor_mem_is_zero(const char *mem, size_t len);
 227 int tor_digest_is_zero(const char *digest);
 228 int tor_digest256_is_zero(const char *digest);
 229 char *esc_for_log(const char *string) ATTR_MALLOC;
 230 const char *escaped(const char *string);
 231 struct smartlist_t;
 232 int tor_vsscanf(const char *buf, const char *pattern, va_list ap)
 233 #ifdef __GNUC__
 234   __attribute__((format(scanf, 2, 0)))
 235 #endif
 236   ;
 237 int tor_sscanf(const char *buf, const char *pattern, ...)
 238 #ifdef __GNUC__
 239   __attribute__((format(scanf, 2, 3)))
 240 #endif
 241   ;
 242
 243 void smartlist_add_asprintf(struct smartlist_t *sl, const char *pattern, ...)
 244   CHECK_PRINTF(2, 3);
 245 void smartlist_add_vasprintf(struct smartlist_t *sl, const char *pattern,
 246                              va_list args)
 247   CHECK_PRINTF(2, 0);
 248
 249 int hex_decode_digit(char c);
 250 void base16_encode(char *dest, size_t destlen, const char *src, size_t srclen);
 251 int base16_decode(char *dest, size_t destlen, const char *src, size_t srclen);
 252
 253 /* Time helpers */
 254 long tv_udiff(const struct timeval *start, const struct timeval *end);
 255 long tv_mdiff(const struct timeval *start, const struct timeval *end);
 256 int tor_timegm(const struct tm *tm, time_t *time_out);
 257 #define RFC1123_TIME_LEN 29
 258 void format_rfc1123_time(char *buf, time_t t);
 259 int parse_rfc1123_time(const char *buf, time_t *t);
 260 #define ISO_TIME_LEN 19
 261 #define ISO_TIME_USEC_LEN (ISO_TIME_LEN+7)
 262 void format_local_iso_time(char *buf, time_t t);
 263 void format_iso_time(char *buf, time_t t);
 264 void format_iso_time_nospace(char *buf, time_t t);
 265 void format_iso_time_nospace_usec(char *buf, const struct timeval *tv);
 266 int parse_iso_time(const char *buf, time_t *t);
 267 int parse_http_time(const char *buf, struct tm *tm);
 268 int format_time_interval(char *out, size_t out_len, long interval);
 269
 270 /* Cached time */
 271 #ifdef TIME_IS_FAST
 272 #define approx_time() time(NULL)
 273 #define update_approx_time(t) STMT_NIL
 274 #else
 275 time_t approx_time(void);
 276 void update_approx_time(time_t now);
 277 #endif
 278
 279 /* Rate-limiter */
 280
 281 /** A ratelim_t remembers how often an event is occurring, and how often
 282  * it's allowed to occur.  Typical usage is something like:
 283  *
 284    <pre>
 285     if (possibly_very_frequent_event()) {
 286       const int INTERVAL = 300;
 287       static ratelim_t warning_limit = RATELIM_INIT(INTERVAL);
 288       char *m;
 289       if ((m = rate_limit_log(&warning_limit, approx_time()))) {
 290         log_warn(LD_GENERAL, "The event occurred!%s", m);
 291         tor_free(m);
 292       }
 293     }
 294    </pre>
 295
 296    As a convenience wrapper for logging, you can replace the above with:
 297    <pre>
 298    if (possibly_very_frequent_event()) {
 299      static ratelim_t warning_limit = RATELIM_INIT(300);
 300      log_fn_ratelim(&warning_limit, LOG_WARN, LD_GENERAL,
 301                     "The event occurred!");
 302    }
 303    </pre>
 304  */
 305 typedef struct ratelim_t {
 306   int rate;
 307   time_t last_allowed;
 308   int n_calls_since_last_time;
 309 } ratelim_t;
 310
 311 #define RATELIM_INIT(r) { (r), 0, 0 }
 312
 313 char *rate_limit_log(ratelim_t *lim, time_t now);
 314
 315 /* File helpers */
 316 ssize_t write_all(tor_socket_t fd, const char *buf, size_t count,int isSocket);
 317 ssize_t read_all(tor_socket_t fd, char *buf, size_t count, int isSocket);
 318
 319 /** Status of an I/O stream. */
 320 enum stream_status {
 321   IO_STREAM_OKAY,
 322   IO_STREAM_EAGAIN,
 323   IO_STREAM_TERM,
 324   IO_STREAM_CLOSED
 325 };
 326
 327 const char *stream_status_to_string(enum stream_status stream_status);
 328
 329 enum stream_status get_string_from_pipe(FILE *stream, char *buf, size_t count);
 330
 331 /** Return values from file_status(); see that function's documentation
 332  * for details. */
 333 typedef enum { FN_ERROR, FN_NOENT, FN_FILE, FN_DIR } file_status_t;
 334 file_status_t file_status(const char *filename);
 335
 336 /** Possible behaviors for check_private_dir() on encountering a nonexistent
 337  * directory; see that function's documentation for details. */
 338 typedef unsigned int cpd_check_t;
 339 #define CPD_NONE 0
 340 #define CPD_CREATE 1
 341 #define CPD_CHECK 2
 342 #define CPD_GROUP_OK 4
 343 #define CPD_CHECK_MODE_ONLY 8
 344 int check_private_dir(const char *dirname, cpd_check_t check,
 345                       const char *effective_user);
 346 #define OPEN_FLAGS_REPLACE (O_WRONLY|O_CREAT|O_TRUNC)
 347 #define OPEN_FLAGS_APPEND (O_WRONLY|O_CREAT|O_APPEND)
 348 #define OPEN_FLAGS_DONT_REPLACE (O_CREAT|O_EXCL|O_APPEND|O_WRONLY)
 349 typedef struct open_file_t open_file_t;
 350 int start_writing_to_file(const char *fname, int open_flags, int mode,
 351                           open_file_t **data_out);
 352 FILE *start_writing_to_stdio_file(const char *fname, int open_flags, int mode,
 353                                   open_file_t **data_out);
 354 FILE *fdopen_file(open_file_t *file_data);
 355 int finish_writing_to_file(open_file_t *file_data);
 356 int abort_writing_to_file(open_file_t *file_data);
 357 int write_str_to_file(const char *fname, const char *str, int bin);
 358 int write_bytes_to_file(const char *fname, const char *str, size_t len,
 359                         int bin);
 360 /** An ad-hoc type to hold a string of characters and a count; used by
 361  * write_chunks_to_file. */
 362 typedef struct sized_chunk_t {
 363   const char *bytes;
 364   size_t len;
 365 } sized_chunk_t;
 366 int write_chunks_to_file(const char *fname, const struct smartlist_t *chunks,
 367                          int bin);
 368 int append_bytes_to_file(const char *fname, const char *str, size_t len,
 369                          int bin);
 370 int write_bytes_to_new_file(const char *fname, const char *str, size_t len,
 371                             int bin);
 372
 373 /** Flag for read_file_to_str: open the file in binary mode. */
 374 #define RFTS_BIN            1
 375 /** Flag for read_file_to_str: it's okay if the file doesn't exist. */
 376 #define RFTS_IGNORE_MISSING 2
 377
 378 #ifndef _WIN32
 379 struct stat;
 380 #endif
 381 char *read_file_to_str(const char *filename, int flags, struct stat *stat_out)
 382   ATTR_MALLOC;
 383 char *read_file_to_str_until_eof(int fd, size_t max_bytes_to_read,
 384                                  size_t *sz_out)
 385   ATTR_MALLOC;
 386 const char *parse_config_line_from_str_verbose(const char *line,
 387                                        char **key_out, char **value_out,
 388                                        const char **err_out);
 389 #define parse_config_line_from_str(line,key_out,value_out) \
 390   parse_config_line_from_str_verbose((line),(key_out),(value_out),NULL)
 391 char *expand_filename(const char *filename);
 392 struct smartlist_t *tor_listdir(const char *dirname);
 393 int path_is_relative(const char *filename);
 394
 395 /* Process helpers */
 396 void start_daemon(void);
 397 void finish_daemon(const char *desired_cwd);
 398 void write_pidfile(char *filename);
 399
 400 /* Port forwarding */
 401 void tor_check_port_forwarding(const char *filename,
 402                                struct smartlist_t *ports_to_forward,
 403                                time_t now);
 404
 405 typedef struct process_handle_t process_handle_t;
 406 typedef struct process_environment_t process_environment_t;
 407 int tor_spawn_background(const char *const filename, const char **argv,
 408                          process_environment_t *env,
 409                          process_handle_t **process_handle_out);
 410
 411 #define SPAWN_ERROR_MESSAGE "ERR: Failed to spawn background process - code "
 412
 413 #ifdef _WIN32
 414 HANDLE load_windows_system_library(const TCHAR *library_name);
 415 #endif
 416
 417 int environment_variable_names_equal(const char *s1, const char *s2);
 418
 419 /* DOCDOC process_environment_t */
 420 struct process_environment_t {
 421   /** A pointer to a sorted empty-string-terminated sequence of
 422    * NUL-terminated strings of the form "NAME=VALUE". */
 423   char *windows_environment_block;
 424   /** A pointer to a NULL-terminated array of pointers to
 425    * NUL-terminated strings of the form "NAME=VALUE". */
 426   char **unixoid_environment_block;
 427 };
 428
 429 process_environment_t *process_environment_make(struct smartlist_t *env_vars);
 430 void process_environment_free(process_environment_t *env);
 431
 432 struct smartlist_t *get_current_process_environment_variables(void);
 433
 434 void set_environment_variable_in_smartlist(struct smartlist_t *env_vars,
 435                                            const char *new_var,
 436                                            void (*free_old)(void*),
 437                                            int free_p);
 438
 439 /* Values of process_handle_t.status. PROCESS_STATUS_NOTRUNNING must be
 440  * 0 because tor_check_port_forwarding depends on this being the initial
 441  * statue of the static instance of process_handle_t */
 442 #define PROCESS_STATUS_NOTRUNNING 0
 443 #define PROCESS_STATUS_RUNNING 1
 444 #define PROCESS_STATUS_ERROR -1
 445
 446 #ifdef UTIL_PRIVATE
 447 /** Structure to represent the state of a process with which Tor is
 448  * communicating. The contents of this structure are private to util.c */
 449 struct process_handle_t {
 450   /** One of the PROCESS_STATUS_* values */
 451   int status;
 452 #ifdef _WIN32
 453   HANDLE stdout_pipe;
 454   HANDLE stderr_pipe;
 455   PROCESS_INFORMATION pid;
 456 #else
 457   int stdout_pipe;
 458   int stderr_pipe;
 459   FILE *stdout_handle;
 460   FILE *stderr_handle;
 461   pid_t pid;
 462 #endif // _WIN32
 463 };
 464 #endif
 465
 466 /* Return values of tor_get_exit_code() */
 467 #define PROCESS_EXIT_RUNNING 1
 468 #define PROCESS_EXIT_EXITED 0
 469 #define PROCESS_EXIT_ERROR -1
 470 int tor_get_exit_code(const process_handle_t *process_handle,
 471                       int block, int *exit_code);
 472 int tor_split_lines(struct smartlist_t *sl, char *buf, int len);
 473 #ifdef _WIN32
 474 ssize_t tor_read_all_handle(HANDLE h, char *buf, size_t count,
 475                             const process_handle_t *process);
 476 #else
 477 ssize_t tor_read_all_handle(FILE *h, char *buf, size_t count,
 478                             const process_handle_t *process,
 479                             int *eof);
 480 #endif
 481 ssize_t tor_read_all_from_process_stdout(
 482     const process_handle_t *process_handle, char *buf, size_t count);
 483 ssize_t tor_read_all_from_process_stderr(
 484     const process_handle_t *process_handle, char *buf, size_t count);
 485 char *tor_join_win_cmdline(const char *argv[]);
 486
 487 int tor_process_get_pid(process_handle_t *process_handle);
 488 #ifdef _WIN32
 489 HANDLE tor_process_get_stdout_pipe(process_handle_t *process_handle);
 490 #else
 491 FILE *tor_process_get_stdout_pipe(process_handle_t *process_handle);
 492 #endif
 493
 494 #ifdef _WIN32
 495 struct smartlist_t *
 496 tor_get_lines_from_handle(HANDLE *handle,
 497                           enum stream_status *stream_status);
 498 #else
 499 struct smartlist_t *
 500 tor_get_lines_from_handle(FILE *handle,
 501                           enum stream_status *stream_status);
 502 #endif
 503
 504 int tor_terminate_process(process_handle_t *process_handle);
 505 void tor_process_handle_destroy(process_handle_t *process_handle,
 506                                 int also_terminate_process);
 507
 508 /* ===== Insecure rng */
 509 typedef struct tor_weak_rng_t {
 510   uint32_t state;
 511 } tor_weak_rng_t;
 512
 513 #define TOR_WEAK_RNG_INIT {383745623}
 514 #define TOR_WEAK_RANDOM_MAX (INT_MAX)
 515 void tor_init_weak_random(tor_weak_rng_t *weak_rng, unsigned seed);
 516 int32_t tor_weak_random(tor_weak_rng_t *weak_rng);
 517 int32_t tor_weak_random_range(tor_weak_rng_t *rng, int32_t top);
 518 /** Randomly return true according to <b>rng</b> with probability 1 in
 519  * <b>n</b> */
 520 #define tor_weak_random_one_in_n(rng, n) (0==tor_weak_random_range((rng),(n)))
 521
 522 #ifdef UTIL_PRIVATE
 523 /* Prototypes for private functions only used by util.c (and unit tests) */
 524
 525 int format_hex_number_for_helper_exit_status(unsigned int x, char *buf,
 526                                              int max_len);
 527 int format_helper_exit_status(unsigned char child_state,
 528                               int saved_errno, char *hex_errno);
 529
 530 /* Space for hex values of child state, a slash, saved_errno (with
 531    leading minus) and newline (no null) */
 532 #define HEX_ERRNO_SIZE (sizeof(char) * 2 + 1 + \
 533                         1 + sizeof(int) * 2 + 1)
 534 #endif
 535
 536 const char *libor_get_digests(void);
 537
 538 #endif
 539