src/common/util.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2011, 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
  21 #ifndef O_BINARY
  22 #define O_BINARY 0
  23 #endif
  24 #ifndef O_TEXT
  25 #define O_TEXT 0
  26 #endif
  27
  28 /* Replace assert() with a variant that sends failures to the log before
  29  * calling assert() normally.
  30  */
  31 #ifdef NDEBUG
  32 /* Nobody should ever want to build with NDEBUG set.  99% of our asserts will
  33  * be outside the critical path anyway, so it's silly to disable bug-checking
  34  * throughout the entire program just because a few asserts are slowing you
  35  * down.  Profile, optimize the critical path, and keep debugging on.
  36  *
  37  * And I'm not just saying that because some of our asserts check
  38  * security-critical properties.
  39  */
  40 #error "Sorry; we don't support building with NDEBUG."
  41 #endif
  42
  43 /** Like assert(3), but send assertion failures to the log as well as to
  44  * stderr. */
  45 #define tor_assert(expr) STMT_BEGIN                                     \
  46     if (PREDICT_UNLIKELY(!(expr))) {                                    \
  47       log_err(LD_BUG, "%s:%d: %s: Assertion %s failed; aborting.",      \
  48           _SHORT_FILE_, __LINE__, __func__, #expr);                     \
  49       fprintf(stderr,"%s:%d %s: Assertion %s failed; aborting.\n",      \
  50               _SHORT_FILE_, __LINE__, __func__, #expr);                 \
  51       abort();                                                          \
  52     } STMT_END
  53
  54 /* If we're building with dmalloc, we want all of our memory allocation
  55  * functions to take an extra file/line pair of arguments.  If not, not.
  56  * We define DMALLOC_PARAMS to the extra parameters to insert in the
  57  * function prototypes, and DMALLOC_ARGS to the extra arguments to add
  58  * to calls. */
  59 #ifdef USE_DMALLOC
  60 #define DMALLOC_PARAMS , const char *file, const int line
  61 #define DMALLOC_ARGS , _SHORT_FILE_, __LINE__
  62 #else
  63 #define DMALLOC_PARAMS
  64 #define DMALLOC_ARGS
  65 #endif
  66
  67 /** Define this if you want Tor to crash when any problem comes up,
  68  * so you can get a coredump and track things down. */
  69 // #define tor_fragile_assert() tor_assert(0)
  70 #define tor_fragile_assert()
  71
  72 /* Memory management */
  73 void *_tor_malloc(size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  74 void *_tor_malloc_zero(size_t size DMALLOC_PARAMS) ATTR_MALLOC;
  75 void *_tor_malloc_roundup(size_t *size DMALLOC_PARAMS) ATTR_MALLOC;
  76 void *_tor_realloc(void *ptr, size_t size DMALLOC_PARAMS);
  77 char *_tor_strdup(const char *s DMALLOC_PARAMS) ATTR_MALLOC ATTR_NONNULL((1));
  78 char *_tor_strndup(const char *s, size_t n DMALLOC_PARAMS)
  79   ATTR_MALLOC ATTR_NONNULL((1));
  80 void *_tor_memdup(const void *mem, size_t len DMALLOC_PARAMS)
  81   ATTR_MALLOC ATTR_NONNULL((1));
  82 void _tor_free(void *mem);
  83 #ifdef USE_DMALLOC
  84 extern int dmalloc_free(const char *file, const int line, void *pnt,
  85                         const int func_id);
  86 #define tor_free(p) STMT_BEGIN \
  87     if (PREDICT_LIKELY((p)!=NULL)) {                \
  88       dmalloc_free(_SHORT_FILE_, __LINE__, (p), 0); \
  89       (p)=NULL;                                     \
  90     }                                               \
  91   STMT_END
  92 #else
  93 /** Release memory allocated by tor_malloc, tor_realloc, tor_strdup, etc.
  94  * Unlike the free() function, tor_free() will still work on NULL pointers,
  95  * and it sets the pointer value to NULL after freeing it.
  96  *
  97  * This is a macro.  If you need a function pointer to release memory from
  98  * tor_malloc(), use _tor_free().
  99  */
 100 #define tor_free(p) STMT_BEGIN                                 \
 101     if (PREDICT_LIKELY((p)!=NULL)) {                           \
 102       free(p);                                                 \
 103       (p)=NULL;                                                \
 104     }                                                          \
 105   STMT_END
 106 #endif
 107
 108 #define tor_malloc(size)       _tor_malloc(size DMALLOC_ARGS)
 109 #define tor_malloc_zero(size)  _tor_malloc_zero(size DMALLOC_ARGS)
 110 #define tor_malloc_roundup(szp) _tor_malloc_roundup(szp DMALLOC_ARGS)
 111 #define tor_realloc(ptr, size) _tor_realloc(ptr, size DMALLOC_ARGS)
 112 #define tor_strdup(s)          _tor_strdup(s DMALLOC_ARGS)
 113 #define tor_strndup(s, n)      _tor_strndup(s, n DMALLOC_ARGS)
 114 #define tor_memdup(s, n)       _tor_memdup(s, n DMALLOC_ARGS)
 115
 116 void tor_log_mallinfo(int severity);
 117
 118 /** Return the offset of <b>member</b> within the type <b>tp</b>, in bytes */
 119 #if defined(__GNUC__) && __GNUC__ > 3
 120 #define STRUCT_OFFSET(tp, member) __builtin_offsetof(tp, member)
 121 #else
 122  #define STRUCT_OFFSET(tp, member) \
 123    ((off_t) (((char*)&((tp*)0)->member)-(char*)0))
 124 #endif
 125
 126 /** Macro: yield a pointer to the field at position <b>off</b> within the
 127  * structure <b>st</b>.  Example:
 128  * <pre>
 129  *   struct a { int foo; int bar; } x;
 130  *   off_t bar_offset = STRUCT_OFFSET(struct a, bar);
 131  *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);
 132  *   *bar_p = 3;
 133  * </pre>
 134  */
 135 #define STRUCT_VAR_P(st, off) ((void*) ( ((char*)(st)) + (off) ) )
 136
 137 /** Macro: yield a pointer to an enclosing structure given a pointer to
 138  * a substructure at offset <b>off</b>. Example:
 139  * <pre>
 140  *   struct base { ... };
 141  *   struct subtype { int x; struct base b; } x;
 142  *   struct base *bp = &x.base;
 143  *   struct *sp = SUBTYPE_P(bp, struct subtype, b);
 144  * </pre>
 145  */
 146 #define SUBTYPE_P(p, subtype, basemember) \
 147   ((void*) ( ((char*)(p)) - STRUCT_OFFSET(subtype, basemember) ))
 148
 149 /* Logic */
 150 /** Macro: true if two values have the same boolean value. */
 151 #define bool_eq(a,b) (!(a)==!(b))
 152 /** Macro: true if two values have different boolean values. */
 153 #define bool_neq(a,b) (!(a)!=!(b))
 154
 155 /* Math functions */
 156 double tor_mathlog(double d) ATTR_CONST;
 157 long tor_lround(double d) ATTR_CONST;
 158 int tor_log2(uint64_t u64) ATTR_CONST;
 159 uint64_t round_to_power_of_2(uint64_t u64);
 160 unsigned round_to_next_multiple_of(unsigned number, unsigned divisor);
 161 uint32_t round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor);
 162 uint64_t round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor);
 163
 164 /* Compute the CEIL of <b>a</b> divided by <b>b</b>, for nonnegative <b>a</b>
 165  * and positive <b>b</b>.  Works on integer types only. Not defined if a+b can
 166  * overflow. */
 167 #define CEIL_DIV(a,b) (((a)+(b)-1)/(b))
 168
 169 /* String manipulation */
 170
 171 /** Allowable characters in a hexadecimal string. */
 172 #define HEX_CHARACTERS "0123456789ABCDEFabcdef"
 173 void tor_strlower(char *s) ATTR_NONNULL((1));
 174 void tor_strupper(char *s) ATTR_NONNULL((1));
 175 int tor_strisprint(const char *s) ATTR_PURE ATTR_NONNULL((1));
 176 int tor_strisnonupper(const char *s) ATTR_PURE ATTR_NONNULL((1));
 177 int strcmpstart(const char *s1, const char *s2) ATTR_PURE ATTR_NONNULL((1,2));
 178 int strcmp_len(const char *s1, const char *s2, size_t len)
 179   ATTR_PURE ATTR_NONNULL((1,2));
 180 int strcasecmpstart(const char *s1, const char *s2)
 181   ATTR_PURE ATTR_NONNULL((1,2));
 182 int strcmpend(const char *s1, const char *s2) ATTR_PURE ATTR_NONNULL((1,2));
 183 int strcasecmpend(const char *s1, const char *s2)
 184   ATTR_PURE ATTR_NONNULL((1,2));
 185 int fast_memcmpstart(const void *mem, size_t memlen,
 186                      const char *prefix) ATTR_PURE;
 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) ATTR_PURE;
 199 const char *eat_whitespace_eos(const char *s, const char *eos) ATTR_PURE;
 200 const char *eat_whitespace_no_nl(const char *s) ATTR_PURE;
 201 const char *eat_whitespace_eos_no_nl(const char *s, const char *eos) ATTR_PURE;
 202 const char *find_whitespace(const char *s) ATTR_PURE;
 203 const char *find_whitespace_eos(const char *s, const char *eos) ATTR_PURE;
 204 const char *find_str_at_start_of_line(const char *haystack, const char *needle)
 205   ATTR_PURE;
 206 int tor_mem_is_zero(const char *mem, size_t len) ATTR_PURE;
 207 int tor_digest_is_zero(const char *digest) ATTR_PURE;
 208 int tor_digest256_is_zero(const char *digest) ATTR_PURE;
 209 char *esc_for_log(const char *string) ATTR_MALLOC;
 210 const char *escaped(const char *string);
 211 struct smartlist_t;
 212 void wrap_string(struct smartlist_t *out, const char *string, size_t width,
 213                  const char *prefix0, const char *prefixRest);
 214 int tor_vsscanf(const char *buf, const char *pattern, va_list ap);
 215 int tor_sscanf(const char *buf, const char *pattern, ...)
 216 #ifdef __GNUC__
 217   __attribute__((format(scanf, 2, 3)))
 218 #endif
 219   ;
 220
 221 int hex_decode_digit(char c);
 222 void base16_encode(char *dest, size_t destlen, const char *src, size_t srclen);
 223 int base16_decode(char *dest, size_t destlen, const char *src, size_t srclen);
 224
 225 /* Time helpers */
 226 double tv_to_double(const struct timeval *tv);
 227 int64_t tv_to_msec(const struct timeval *tv);
 228 int64_t tv_to_usec(const struct timeval *tv);
 229 long tv_udiff(const struct timeval *start, const struct timeval *end);
 230 long tv_mdiff(const struct timeval *start, const struct timeval *end);
 231 time_t tor_timegm(struct tm *tm);
 232 #define RFC1123_TIME_LEN 29
 233 void format_rfc1123_time(char *buf, time_t t);
 234 int parse_rfc1123_time(const char *buf, time_t *t);
 235 #define ISO_TIME_LEN 19
 236 void format_local_iso_time(char *buf, time_t t);
 237 void format_iso_time(char *buf, time_t t);
 238 int parse_iso_time(const char *buf, time_t *t);
 239 int parse_http_time(const char *buf, struct tm *tm);
 240 int format_time_interval(char *out, size_t out_len, long interval);
 241
 242 /* Cached time */
 243 #ifdef TIME_IS_FAST
 244 #define approx_time() time(NULL)
 245 #define update_approx_time(t) STMT_NIL
 246 #else
 247 time_t approx_time(void);
 248 void update_approx_time(time_t now);
 249 #endif
 250
 251 /* Rate-limiter */
 252
 253 /** A ratelim_t remembers how often an event is occurring, and how often
 254  * it's allowed to occur.  Typical usage is something like:
 255  *
 256    <pre>
 257     if (possibly_very_frequent_event()) {
 258       const int INTERVAL = 300;
 259       static ratelim_t warning_limit = RATELIM_INIT(INTERVAL);
 260       char *m;
 261       if ((m = rate_limit_log(&warning_limit, approx_time()))) {
 262         log_warn(LD_GENERAL, "The event occurred!%s", m);
 263         tor_free(m);
 264       }
 265     }
 266    </pre>
 267  */
 268 typedef struct ratelim_t {
 269   int rate;
 270   time_t last_allowed;
 271   int n_calls_since_last_time;
 272 } ratelim_t;
 273
 274 #define RATELIM_INIT(r) { (r), 0, 0 }
 275
 276 char *rate_limit_log(ratelim_t *lim, time_t now);
 277
 278 /* File helpers */
 279 ssize_t write_all(int fd, const char *buf, size_t count, int isSocket);
 280 ssize_t read_all(int fd, char *buf, size_t count, int isSocket);
 281
 282 /** Return values from file_status(); see that function's documentation
 283  * for details. */
 284 typedef enum { FN_ERROR, FN_NOENT, FN_FILE, FN_DIR } file_status_t;
 285 file_status_t file_status(const char *filename);
 286
 287 /** Possible behaviors for check_private_dir() on encountering a nonexistent
 288  * directory; see that function's documentation for details. */
 289 typedef unsigned int cpd_check_t;
 290 #define CPD_NONE 0
 291 #define CPD_CREATE 1
 292 #define CPD_CHECK 2
 293 #define CPD_GROUP_OK 4
 294 #define CPD_CHECK_MODE_ONLY 8
 295 int check_private_dir(const char *dirname, cpd_check_t check);
 296 #define OPEN_FLAGS_REPLACE (O_WRONLY|O_CREAT|O_TRUNC)
 297 #define OPEN_FLAGS_APPEND (O_WRONLY|O_CREAT|O_APPEND)
 298 typedef struct open_file_t open_file_t;
 299 int start_writing_to_file(const char *fname, int open_flags, int mode,
 300                           open_file_t **data_out);
 301 FILE *start_writing_to_stdio_file(const char *fname, int open_flags, int mode,
 302                                   open_file_t **data_out);
 303 FILE *fdopen_file(open_file_t *file_data);
 304 int finish_writing_to_file(open_file_t *file_data);
 305 int abort_writing_to_file(open_file_t *file_data);
 306 int write_str_to_file(const char *fname, const char *str, int bin);
 307 int write_bytes_to_file(const char *fname, const char *str, size_t len,
 308                         int bin);
 309 /** An ad-hoc type to hold a string of characters and a count; used by
 310  * write_chunks_to_file. */
 311 typedef struct sized_chunk_t {
 312   const char *bytes;
 313   size_t len;
 314 } sized_chunk_t;
 315 int write_chunks_to_file(const char *fname, const struct smartlist_t *chunks,
 316                          int bin);
 317 int append_bytes_to_file(const char *fname, const char *str, size_t len,
 318                          int bin);
 319
 320 /** Flag for read_file_to_str: open the file in binary mode. */
 321 #define RFTS_BIN            1
 322 /** Flag for read_file_to_str: it's okay if the file doesn't exist. */
 323 #define RFTS_IGNORE_MISSING 2
 324
 325 struct stat;
 326 char *read_file_to_str(const char *filename, int flags, struct stat *stat_out)
 327   ATTR_MALLOC;
 328 const char *parse_config_line_from_str(const char *line,
 329                                        char **key_out, char **value_out);
 330 char *expand_filename(const char *filename);
 331 struct smartlist_t *tor_listdir(const char *dirname);
 332 int path_is_relative(const char *filename) ATTR_PURE;
 333
 334 /* Process helpers */
 335 void start_daemon(void);
 336 void finish_daemon(const char *desired_cwd);
 337 void write_pidfile(char *filename);
 338
 339 #ifdef MS_WINDOWS
 340 HANDLE load_windows_system_library(const TCHAR *library_name);
 341 #endif
 342
 343 const char *libor_get_digests(void);
 344
 345 #endif
 346