src/common/util.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2016, 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 "testsupport.h"
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #ifdef _WIN32
  22 /* for the correct alias to struct stat */
  23 #include <sys/stat.h>
  24 #endif
  25 #include "util_bug.h"
  26
  27 #ifndef O_BINARY
  28 #define O_BINARY 0
  29 #endif
  30 #ifndef O_TEXT
  31 #define O_TEXT 0
  32 #endif
  33 #ifndef O_NOFOLLOW
  34 #define O_NOFOLLOW 0
  35 #endif
  36
  37 /* If we're building with dmalloc, we want all of our memory allocation
  38  * functions to take an extra file/line pair of arguments.  If not, not.
  39  * We define DMALLOC_PARAMS to the extra parameters to insert in the
  40  * function prototypes, and DMALLOC_ARGS to the extra arguments to add
  41  * to calls. */
  42 #ifdef USE_DMALLOC
  43 #define DMALLOC_PARAMS , const char *file, const int line
  44 #define DMALLOC_ARGS , SHORT_FILE__, __LINE__
  45 #else
  46 #define DMALLOC_PARAMS
  47 #define DMALLOC_ARGS
  48 #endif
  49
  50 /* Memory management */
  51 void *tor_malloc_(size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  52 void *tor_malloc_zero_(size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  53 void *tor_calloc_(size_t nmemb, size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  54 void *tor_realloc_(void *ptr, size_t size DMALLOC_PARAMS);
  55 void *tor_reallocarray_(void *ptr, size_t size1, size_t size2 DMALLOC_PARAMS);
  56 char *tor_strdup_(const char *s DMALLOC_PARAMS) ATTR_MALLOC ATTR_NONNULL((1));
  57 char *tor_strndup_(const char *s, size_t n DMALLOC_PARAMS)
  58   ATTR_MALLOC ATTR_NONNULL((1));
  59 void *tor_memdup_(const void *mem, size_t len DMALLOC_PARAMS)
  60   ATTR_MALLOC ATTR_NONNULL((1));
  61 void *tor_memdup_nulterm_(const void *mem, size_t len DMALLOC_PARAMS)
  62   ATTR_MALLOC ATTR_NONNULL((1));
  63 void tor_free_(void *mem);
  64 uint64_t tor_htonll(uint64_t a);
  65 uint64_t tor_ntohll(uint64_t a);
  66 #ifdef USE_DMALLOC
  67 extern int dmalloc_free(const char *file, const int line, void *pnt,
  68                         const int func_id);
  69 #define tor_free(p) STMT_BEGIN \
  70     if (PREDICT_LIKELY((p)!=NULL)) {                \
  71       dmalloc_free(SHORT_FILE__, __LINE__, (p), 0); \
  72       (p)=NULL;                                     \
  73     }                                               \
  74   STMT_END
  75 #else
  76 /** Release memory allocated by tor_malloc, tor_realloc, tor_strdup, etc.
  77  * Unlike the free() function, tor_free() will still work on NULL pointers,
  78  * and it sets the pointer value to NULL after freeing it.
  79  *
  80  * This is a macro.  If you need a function pointer to release memory from
  81  * tor_malloc(), use tor_free_().
  82  */
  83 #define tor_free(p) STMT_BEGIN                                 \
  84     if (PREDICT_LIKELY((p)!=NULL)) {                           \
  85       free(p);                                                 \
  86       (p)=NULL;                                                \
  87     }                                                          \
  88   STMT_END
  89 #endif
  90
  91 #define tor_malloc(size)       tor_malloc_(size DMALLOC_ARGS)
  92 #define tor_malloc_zero(size)  tor_malloc_zero_(size DMALLOC_ARGS)
  93 #define tor_calloc(nmemb,size) tor_calloc_(nmemb, size DMALLOC_ARGS)
  94 #define tor_realloc(ptr, size) tor_realloc_(ptr, size DMALLOC_ARGS)
  95 #define tor_reallocarray(ptr, sz1, sz2) \
  96   tor_reallocarray_((ptr), (sz1), (sz2) DMALLOC_ARGS)
  97 #define tor_strdup(s)          tor_strdup_(s DMALLOC_ARGS)
  98 #define tor_strndup(s, n)      tor_strndup_(s, n DMALLOC_ARGS)
  99 #define tor_memdup(s, n)       tor_memdup_(s, n DMALLOC_ARGS)
 100 #define tor_memdup_nulterm(s, n)       tor_memdup_nulterm_(s, n DMALLOC_ARGS)
 101
 102 void tor_log_mallinfo(int severity);
 103
 104 /** Return the offset of <b>member</b> within the type <b>tp</b>, in bytes */
 105 #if defined(__GNUC__) && __GNUC__ > 3
 106 #define STRUCT_OFFSET(tp, member) __builtin_offsetof(tp, member)
 107 #else
 108  #define STRUCT_OFFSET(tp, member) \
 109    ((off_t) (((char*)&((tp*)0)->member)-(char*)0))
 110 #endif
 111
 112 /** Macro: yield a pointer to the field at position <b>off</b> within the
 113  * structure <b>st</b>.  Example:
 114  * <pre>
 115  *   struct a { int foo; int bar; } x;
 116  *   off_t bar_offset = STRUCT_OFFSET(struct a, bar);
 117  *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);
 118  *   *bar_p = 3;
 119  * </pre>
 120  */
 121 #define STRUCT_VAR_P(st, off) ((void*) ( ((char*)(st)) + (off) ) )
 122
 123 /** Macro: yield a pointer to an enclosing structure given a pointer to
 124  * a substructure at offset <b>off</b>. Example:
 125  * <pre>
 126  *   struct base { ... };
 127  *   struct subtype { int x; struct base b; } x;
 128  *   struct base *bp = &x.base;
 129  *   struct *sp = SUBTYPE_P(bp, struct subtype, b);
 130  * </pre>
 131  */
 132 #define SUBTYPE_P(p, subtype, basemember) \
 133   ((void*) ( ((char*)(p)) - STRUCT_OFFSET(subtype, basemember) ))
 134
 135 /* Logic */
 136 /** Macro: true if two values have the same boolean value. */
 137 #define bool_eq(a,b) (!(a)==!(b))
 138 /** Macro: true if two values have different boolean values. */
 139 #define bool_neq(a,b) (!(a)!=!(b))
 140
 141 /* Math functions */
 142 double tor_mathlog(double d) ATTR_CONST;
 143 long tor_lround(double d) ATTR_CONST;
 144 int64_t tor_llround(double d) ATTR_CONST;
 145 int tor_log2(uint64_t u64) ATTR_CONST;
 146 uint64_t round_to_power_of_2(uint64_t u64);
 147 unsigned round_to_next_multiple_of(unsigned number, unsigned divisor);
 148 uint32_t round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor);
 149 uint64_t round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor);
 150 int64_t sample_laplace_distribution(double mu, double b, double p);
 151 int64_t add_laplace_noise(int64_t signal, double random, double delta_f,
 152                           double epsilon);
 153 int n_bits_set_u8(uint8_t v);
 154 int64_t clamp_double_to_int64(double number);
 155
 156 /* Compute the CEIL of <b>a</b> divided by <b>b</b>, for nonnegative <b>a</b>
 157  * and positive <b>b</b>.  Works on integer types only. Not defined if a+b can
 158  * overflow. */
 159 #define CEIL_DIV(a,b) (((a)+(b)-1)/(b))
 160
 161 /* Return <b>v</b> if it's between <b>min</b> and <b>max</b>.  Otherwise
 162  * return <b>min</b> if <b>v</b> is smaller than <b>min</b>, or <b>max</b> if
 163  * <b>b</b> is larger than <b>max</b>.
 164  *
 165  * Requires that <b>min</b> is no more than <b>max</b>. May evaluate any of
 166  * its arguments more than once! */
 167 #define CLAMP(min,v,max)                        \
 168   ( ((v) < (min)) ? (min) :                     \
 169     ((v) > (max)) ? (max) :                     \
 170     (v) )
 171
 172 /* String manipulation */
 173
 174 /** Allowable characters in a hexadecimal string. */
 175 #define HEX_CHARACTERS "0123456789ABCDEFabcdef"
 176 void tor_strlower(char *s) ATTR_NONNULL((1));
 177 void tor_strupper(char *s) ATTR_NONNULL((1));
 178 int tor_strisprint(const char *s) ATTR_NONNULL((1));
 179 int tor_strisnonupper(const char *s) ATTR_NONNULL((1));
 180 int strcmp_opt(const char *s1, const char *s2);
 181 int strcmpstart(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 182 int strcmp_len(const char *s1, const char *s2, size_t len) ATTR_NONNULL((1,2));
 183 int strcasecmpstart(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 184 int strcmpend(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 185 int strcasecmpend(const char *s1, const char *s2) ATTR_NONNULL((1,2));
 186 int fast_memcmpstart(const void *mem, size_t memlen, const char *prefix);
 187
 188 void tor_strstrip(char *s, const char *strip) ATTR_NONNULL((1,2));
 189 long tor_parse_long(const char *s, int base, long min,
 190                     long max, int *ok, char **next);
 191 unsigned long tor_parse_ulong(const char *s, int base, unsigned long min,
 192                               unsigned long max, int *ok, char **next);
 193 double tor_parse_double(const char *s, double min, double max, int *ok,
 194                         char **next);
 195 uint64_t tor_parse_uint64(const char *s, int base, uint64_t min,
 196                          uint64_t max, int *ok, char **next);
 197 const char *hex_str(const char *from, size_t fromlen) ATTR_NONNULL((1));
 198 const char *eat_whitespace(const char *s);
 199 const char *eat_whitespace_eos(const char *s, const char *eos);
 200 const char *eat_whitespace_no_nl(const char *s);
 201 const char *eat_whitespace_eos_no_nl(const char *s, const char *eos);
 202 const char *find_whitespace(const char *s);
 203 const char *find_whitespace_eos(const char *s, const char *eos);
 204 const char *find_str_at_start_of_line(const char *haystack,
 205                                       const char *needle);
 206 int string_is_C_identifier(const char *string);
 207 int string_is_key_value(int severity, const char *string);
 208 int string_is_valid_hostname(const char *string);
 209 int string_is_valid_ipv4_address(const char *string);
 210 int string_is_valid_ipv6_address(const char *string);
 211
 212 int tor_mem_is_zero(const char *mem, size_t len);
 213 int tor_digest_is_zero(const char *digest);
 214 int tor_digest256_is_zero(const char *digest);
 215 char *esc_for_log(const char *string) ATTR_MALLOC;
 216 char *esc_for_log_len(const char *chars, size_t n) ATTR_MALLOC;
 217 const char *escaped(const char *string);
 218
 219 char *tor_escape_str_for_pt_args(const char *string,
 220                                  const char *chars_to_escape);
 221
 222 struct smartlist_t;
 223 int tor_vsscanf(const char *buf, const char *pattern, va_list ap) \
 224   CHECK_SCANF(2, 0);
 225 int tor_sscanf(const char *buf, const char *pattern, ...)
 226   CHECK_SCANF(2, 3);
 227
 228 void smartlist_add_asprintf(struct smartlist_t *sl, const char *pattern, ...)
 229   CHECK_PRINTF(2, 3);
 230 void smartlist_add_vasprintf(struct smartlist_t *sl, const char *pattern,
 231                              va_list args)
 232   CHECK_PRINTF(2, 0);
 233
 234 /* Time helpers */
 235 long tv_udiff(const struct timeval *start, const struct timeval *end);
 236 long tv_mdiff(const struct timeval *start, const struct timeval *end);
 237 int64_t tv_to_msec(const struct timeval *tv);
 238 int tor_timegm(const struct tm *tm, time_t *time_out);
 239 #define RFC1123_TIME_LEN 29
 240 void format_rfc1123_time(char *buf, time_t t);
 241 int parse_rfc1123_time(const char *buf, time_t *t);
 242 #define ISO_TIME_LEN 19
 243 #define ISO_TIME_USEC_LEN (ISO_TIME_LEN+7)
 244 void format_local_iso_time(char *buf, time_t t);
 245 void format_iso_time(char *buf, time_t t);
 246 void format_iso_time_nospace(char *buf, time_t t);
 247 void format_iso_time_nospace_usec(char *buf, const struct timeval *tv);
 248 int parse_iso_time_(const char *cp, time_t *t, int strict);
 249 int parse_iso_time(const char *buf, time_t *t);
 250 int parse_http_time(const char *buf, struct tm *tm);
 251 int format_time_interval(char *out, size_t out_len, long interval);
 252
 253 /* Cached time */
 254 #ifdef TIME_IS_FAST
 255 #define approx_time() time(NULL)
 256 #define update_approx_time(t) STMT_NIL
 257 #else
 258 time_t approx_time(void);
 259 void update_approx_time(time_t now);
 260 #endif
 261
 262 /* Rate-limiter */
 263
 264 /** A ratelim_t remembers how often an event is occurring, and how often
 265  * it's allowed to occur.  Typical usage is something like:
 266  *
 267    <pre>
 268     if (possibly_very_frequent_event()) {
 269       const int INTERVAL = 300;
 270       static ratelim_t warning_limit = RATELIM_INIT(INTERVAL);
 271       char *m;
 272       if ((m = rate_limit_log(&warning_limit, approx_time()))) {
 273         log_warn(LD_GENERAL, "The event occurred!%s", m);
 274         tor_free(m);
 275       }
 276     }
 277    </pre>
 278
 279    As a convenience wrapper for logging, you can replace the above with:
 280    <pre>
 281    if (possibly_very_frequent_event()) {
 282      static ratelim_t warning_limit = RATELIM_INIT(300);
 283      log_fn_ratelim(&warning_limit, LOG_WARN, LD_GENERAL,
 284                     "The event occurred!");
 285    }
 286    </pre>
 287  */
 288 typedef struct ratelim_t {
 289   int rate;
 290   time_t last_allowed;
 291   int n_calls_since_last_time;
 292 } ratelim_t;
 293
 294 #define RATELIM_INIT(r) { (r), 0, 0 }
 295
 296 char *rate_limit_log(ratelim_t *lim, time_t now);
 297
 298 /* File helpers */
 299 ssize_t write_all(tor_socket_t fd, const char *buf, size_t count,int isSocket);
 300 ssize_t read_all(tor_socket_t fd, char *buf, size_t count, int isSocket);
 301
 302 /** Status of an I/O stream. */
 303 enum stream_status {
 304   IO_STREAM_OKAY,
 305   IO_STREAM_EAGAIN,
 306   IO_STREAM_TERM,
 307   IO_STREAM_CLOSED
 308 };
 309
 310 const char *stream_status_to_string(enum stream_status stream_status);
 311
 312 enum stream_status get_string_from_pipe(FILE *stream, char *buf, size_t count);
 313
 314 /** Return values from file_status(); see that function's documentation
 315  * for details. */
 316 typedef enum { FN_ERROR, FN_NOENT, FN_FILE, FN_DIR, FN_EMPTY } file_status_t;
 317 file_status_t file_status(const char *filename);
 318
 319 /** Possible behaviors for check_private_dir() on encountering a nonexistent
 320  * directory; see that function's documentation for details. */
 321 typedef unsigned int cpd_check_t;
 322 #define CPD_NONE                 0
 323 #define CPD_CREATE               (1u << 0)
 324 #define CPD_CHECK                (1u << 1)
 325 #define CPD_GROUP_OK             (1u << 2)
 326 #define CPD_GROUP_READ           (1u << 3)
 327 #define CPD_CHECK_MODE_ONLY      (1u << 4)
 328 #define CPD_RELAX_DIRMODE_CHECK  (1u << 5)
 329 int check_private_dir(const char *dirname, cpd_check_t check,
 330                       const char *effective_user);
 331
 332 #define OPEN_FLAGS_REPLACE (O_WRONLY|O_CREAT|O_TRUNC)
 333 #define OPEN_FLAGS_APPEND (O_WRONLY|O_CREAT|O_APPEND)
 334 #define OPEN_FLAGS_DONT_REPLACE (O_CREAT|O_EXCL|O_APPEND|O_WRONLY)
 335 typedef struct open_file_t open_file_t;
 336 int start_writing_to_file(const char *fname, int open_flags, int mode,
 337                           open_file_t **data_out);
 338 FILE *start_writing_to_stdio_file(const char *fname, int open_flags, int mode,
 339                                   open_file_t **data_out);
 340 FILE *fdopen_file(open_file_t *file_data);
 341 int finish_writing_to_file(open_file_t *file_data);
 342 int abort_writing_to_file(open_file_t *file_data);
 343 int write_str_to_file(const char *fname, const char *str, int bin);
 344 MOCK_DECL(int,
 345 write_bytes_to_file,(const char *fname, const char *str, size_t len,
 346                      int bin));
 347 /** An ad-hoc type to hold a string of characters and a count; used by
 348  * write_chunks_to_file. */
 349 typedef struct sized_chunk_t {
 350   const char *bytes;
 351   size_t len;
 352 } sized_chunk_t;
 353 int write_chunks_to_file(const char *fname, const struct smartlist_t *chunks,
 354                          int bin, int no_tempfile);
 355 int append_bytes_to_file(const char *fname, const char *str, size_t len,
 356                          int bin);
 357 int write_bytes_to_new_file(const char *fname, const char *str, size_t len,
 358                             int bin);
 359
 360 /** Flag for read_file_to_str: open the file in binary mode. */
 361 #define RFTS_BIN            1
 362 /** Flag for read_file_to_str: it's okay if the file doesn't exist. */
 363 #define RFTS_IGNORE_MISSING 2
 364
 365 #ifndef _WIN32
 366 struct stat;
 367 #endif
 368 char *read_file_to_str(const char *filename, int flags, struct stat *stat_out)
 369   ATTR_MALLOC;
 370 char *read_file_to_str_until_eof(int fd, size_t max_bytes_to_read,
 371                                  size_t *sz_out)
 372   ATTR_MALLOC;
 373 const char *parse_config_line_from_str_verbose(const char *line,
 374                                        char **key_out, char **value_out,
 375                                        const char **err_out);
 376 char *expand_filename(const char *filename);
 377 struct smartlist_t *tor_listdir(const char *dirname);
 378 int path_is_relative(const char *filename);
 379
 380 /* Process helpers */
 381 void start_daemon(void);
 382 void finish_daemon(const char *desired_cwd);
 383 void write_pidfile(const char *filename);
 384
 385 /* Port forwarding */
 386 void tor_check_port_forwarding(const char *filename,
 387                                struct smartlist_t *ports_to_forward,
 388                                time_t now);
 389
 390 typedef struct process_handle_t process_handle_t;
 391 typedef struct process_environment_t process_environment_t;
 392 int tor_spawn_background(const char *const filename, const char **argv,
 393                          process_environment_t *env,
 394                          process_handle_t **process_handle_out);
 395
 396 #define SPAWN_ERROR_MESSAGE "ERR: Failed to spawn background process - code "
 397
 398 #ifdef _WIN32
 399 HANDLE load_windows_system_library(const TCHAR *library_name);
 400 #endif
 401
 402 int environment_variable_names_equal(const char *s1, const char *s2);
 403
 404 /* DOCDOC process_environment_t */
 405 struct process_environment_t {
 406   /** A pointer to a sorted empty-string-terminated sequence of
 407    * NUL-terminated strings of the form "NAME=VALUE". */
 408   char *windows_environment_block;
 409   /** A pointer to a NULL-terminated array of pointers to
 410    * NUL-terminated strings of the form "NAME=VALUE". */
 411   char **unixoid_environment_block;
 412 };
 413
 414 process_environment_t *process_environment_make(struct smartlist_t *env_vars);
 415 void process_environment_free(process_environment_t *env);
 416
 417 struct smartlist_t *get_current_process_environment_variables(void);
 418
 419 void set_environment_variable_in_smartlist(struct smartlist_t *env_vars,
 420                                            const char *new_var,
 421                                            void (*free_old)(void*),
 422                                            int free_p);
 423
 424 /* Values of process_handle_t.status. PROCESS_STATUS_NOTRUNNING must be
 425  * 0 because tor_check_port_forwarding depends on this being the initial
 426  * statue of the static instance of process_handle_t */
 427 #define PROCESS_STATUS_NOTRUNNING 0
 428 #define PROCESS_STATUS_RUNNING 1
 429 #define PROCESS_STATUS_ERROR -1
 430
 431 #ifdef UTIL_PRIVATE
 432 struct waitpid_callback_t;
 433 /** Structure to represent the state of a process with which Tor is
 434  * communicating. The contents of this structure are private to util.c */
 435 struct process_handle_t {
 436   /** One of the PROCESS_STATUS_* values */
 437   int status;
 438 #ifdef _WIN32
 439   HANDLE stdin_pipe;
 440   HANDLE stdout_pipe;
 441   HANDLE stderr_pipe;
 442   PROCESS_INFORMATION pid;
 443 #else
 444   int stdin_pipe;
 445   int stdout_pipe;
 446   int stderr_pipe;
 447   FILE *stdin_handle;
 448   FILE *stdout_handle;
 449   FILE *stderr_handle;
 450   pid_t pid;
 451   /** If the process has not given us a SIGCHLD yet, this has the
 452    * waitpid_callback_t that gets invoked once it has. Otherwise this
 453    * contains NULL. */
 454   struct waitpid_callback_t *waitpid_cb;
 455   /** The exit status reported by waitpid. */
 456   int waitpid_exit_status;
 457 #endif // _WIN32
 458 };
 459 #endif
 460
 461 /* Return values of tor_get_exit_code() */
 462 #define PROCESS_EXIT_RUNNING 1
 463 #define PROCESS_EXIT_EXITED 0
 464 #define PROCESS_EXIT_ERROR -1
 465 int tor_get_exit_code(process_handle_t *process_handle,
 466                       int block, int *exit_code);
 467 int tor_split_lines(struct smartlist_t *sl, char *buf, int len);
 468 #ifdef _WIN32
 469 ssize_t tor_read_all_handle(HANDLE h, char *buf, size_t count,
 470                             const process_handle_t *process);
 471 #else
 472 ssize_t tor_read_all_handle(FILE *h, char *buf, size_t count,
 473                             const process_handle_t *process,
 474                             int *eof);
 475 #endif
 476 ssize_t tor_read_all_from_process_stdout(
 477     const process_handle_t *process_handle, char *buf, size_t count);
 478 ssize_t tor_read_all_from_process_stderr(
 479     const process_handle_t *process_handle, char *buf, size_t count);
 480 char *tor_join_win_cmdline(const char *argv[]);
 481
 482 int tor_process_get_pid(process_handle_t *process_handle);
 483 #ifdef _WIN32
 484 HANDLE tor_process_get_stdout_pipe(process_handle_t *process_handle);
 485 #else
 486 FILE *tor_process_get_stdout_pipe(process_handle_t *process_handle);
 487 #endif
 488
 489 #ifdef _WIN32
 490 MOCK_DECL(struct smartlist_t *,
 491 tor_get_lines_from_handle,(HANDLE *handle,
 492                            enum stream_status *stream_status));
 493 #else
 494 MOCK_DECL(struct smartlist_t *,
 495 tor_get_lines_from_handle,(FILE *handle,
 496                            enum stream_status *stream_status));
 497 #endif
 498
 499 int
 500 tor_terminate_process(process_handle_t *process_handle);
 501
 502 MOCK_DECL(void,
 503 tor_process_handle_destroy,(process_handle_t *process_handle,
 504                             int also_terminate_process));
 505
 506 /* ===== Insecure rng */
 507 typedef struct tor_weak_rng_t {
 508   uint32_t state;
 509 } tor_weak_rng_t;
 510
 511 #define TOR_WEAK_RNG_INIT {383745623}
 512 #define TOR_WEAK_RANDOM_MAX (INT_MAX)
 513 void tor_init_weak_random(tor_weak_rng_t *weak_rng, unsigned seed);
 514 int32_t tor_weak_random(tor_weak_rng_t *weak_rng);
 515 int32_t tor_weak_random_range(tor_weak_rng_t *rng, int32_t top);
 516 /** Randomly return true according to <b>rng</b> with probability 1 in
 517  * <b>n</b> */
 518 #define tor_weak_random_one_in_n(rng, n) (0==tor_weak_random_range((rng),(n)))
 519
 520 int format_hex_number_sigsafe(unsigned long x, char *buf, int max_len);
 521 int format_dec_number_sigsafe(unsigned long x, char *buf, int max_len);
 522
 523 #ifdef UTIL_PRIVATE
 524 /* Prototypes for private functions only used by util.c (and unit tests) */
 525
 526 #ifndef _WIN32
 527 STATIC 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 #endif
 537
 538 #ifdef TOR_UNIT_TESTS
 539 int size_mul_check__(const size_t x, const size_t y);
 540 #endif
 541
 542 #define ARRAY_LENGTH(x) ((sizeof(x)) / sizeof(x[0]))
 543
 544 #endif
 545