util/cutils.c

   1 /*
   2  * Simple C functions to supplement the C library
   3  *
   4  * Copyright (c) 2006 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu-common.h"
  25 #include "qemu/host-utils.h"
  26 #include <math.h>
  27
  28 #include "qemu/sockets.h"
  29 #include "qemu/iov.h"
  30
  31 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
  32 {
  33     int len = qemu_strnlen(str, buf_size);
  34     memcpy(buf, str, len);
  35     memset(buf + len, pad, buf_size - len);
  36 }
  37
  38 void pstrcpy(char *buf, int buf_size, const char *str)
  39 {
  40     int c;
  41     char *q = buf;
  42
  43     if (buf_size <= 0)
  44         return;
  45
  46     for(;;) {
  47         c = *str++;
  48         if (c == 0 || q >= buf + buf_size - 1)
  49             break;
  50         *q++ = c;
  51     }
  52     *q = '\0';
  53 }
  54
  55 /* strcat and truncate. */
  56 char *pstrcat(char *buf, int buf_size, const char *s)
  57 {
  58     int len;
  59     len = strlen(buf);
  60     if (len < buf_size)
  61         pstrcpy(buf + len, buf_size - len, s);
  62     return buf;
  63 }
  64
  65 int strstart(const char *str, const char *val, const char **ptr)
  66 {
  67     const char *p, *q;
  68     p = str;
  69     q = val;
  70     while (*q != '\0') {
  71         if (*p != *q)
  72             return 0;
  73         p++;
  74         q++;
  75     }
  76     if (ptr)
  77         *ptr = p;
  78     return 1;
  79 }
  80
  81 int stristart(const char *str, const char *val, const char **ptr)
  82 {
  83     const char *p, *q;
  84     p = str;
  85     q = val;
  86     while (*q != '\0') {
  87         if (qemu_toupper(*p) != qemu_toupper(*q))
  88             return 0;
  89         p++;
  90         q++;
  91     }
  92     if (ptr)
  93         *ptr = p;
  94     return 1;
  95 }
  96
  97 /* XXX: use host strnlen if available ? */
  98 int qemu_strnlen(const char *s, int max_len)
  99 {
 100     int i;
 101
 102     for(i = 0; i < max_len; i++) {
 103         if (s[i] == '\0') {
 104             break;
 105         }
 106     }
 107     return i;
 108 }
 109
 110 time_t mktimegm(struct tm *tm)
 111 {
 112     time_t t;
 113     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 114     if (m < 3) {
 115         m += 12;
 116         y--;
 117     }
 118     t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
 119                  y / 400 - 719469);
 120     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 121     return t;
 122 }
 123
 124 int qemu_fls(int i)
 125 {
 126     return 32 - clz32(i);
 127 }
 128
 129 /*
 130  * Make sure data goes on disk, but if possible do not bother to
 131  * write out the inode just for timestamp updates.
 132  *
 133  * Unfortunately even in 2009 many operating systems do not support
 134  * fdatasync and have to fall back to fsync.
 135  */
 136 int qemu_fdatasync(int fd)
 137 {
 138 #ifdef CONFIG_FDATASYNC
 139     return fdatasync(fd);
 140 #else
 141     return fsync(fd);
 142 #endif
 143 }
 144
 145 /*
 146  * Searches for an area with non-zero content in a buffer
 147  *
 148  * Attention! The len must be a multiple of
 149  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 150  * and addr must be a multiple of sizeof(VECTYPE) due to
 151  * restriction of optimizations in this function.
 152  *
 153  * can_use_buffer_find_nonzero_offset() can be used to check
 154  * these requirements.
 155  *
 156  * The return value is the offset of the non-zero area rounded
 157  * down to a multiple of sizeof(VECTYPE) for the first
 158  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR chunks and down to
 159  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 160  * afterwards.
 161  *
 162  * If the buffer is all zero the return value is equal to len.
 163  */
 164
 165 size_t buffer_find_nonzero_offset(const void *buf, size_t len)
 166 {
 167     const VECTYPE *p = buf;
 168     const VECTYPE zero = (VECTYPE){0};
 169     size_t i;
 170
 171     assert(can_use_buffer_find_nonzero_offset(buf, len));
 172
 173     if (!len) {
 174         return 0;
 175     }
 176
 177     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 178         if (!ALL_EQ(p[i], zero)) {
 179             return i * sizeof(VECTYPE);
 180         }
 181     }
 182
 183     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 184          i < len / sizeof(VECTYPE);
 185          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 186         VECTYPE tmp0 = p[i + 0] | p[i + 1];
 187         VECTYPE tmp1 = p[i + 2] | p[i + 3];
 188         VECTYPE tmp2 = p[i + 4] | p[i + 5];
 189         VECTYPE tmp3 = p[i + 6] | p[i + 7];
 190         VECTYPE tmp01 = tmp0 | tmp1;
 191         VECTYPE tmp23 = tmp2 | tmp3;
 192         if (!ALL_EQ(tmp01 | tmp23, zero)) {
 193             break;
 194         }
 195     }
 196
 197     return i * sizeof(VECTYPE);
 198 }
 199
 200 /*
 201  * Checks if a buffer is all zeroes
 202  *
 203  * Attention! The len must be a multiple of 4 * sizeof(long) due to
 204  * restriction of optimizations in this function.
 205  */
 206 bool buffer_is_zero(const void *buf, size_t len)
 207 {
 208     /*
 209      * Use long as the biggest available internal data type that fits into the
 210      * CPU register and unroll the loop to smooth out the effect of memory
 211      * latency.
 212      */
 213
 214     size_t i;
 215     long d0, d1, d2, d3;
 216     const long * const data = buf;
 217
 218     /* use vector optimized zero check if possible */
 219     if (can_use_buffer_find_nonzero_offset(buf, len)) {
 220         return buffer_find_nonzero_offset(buf, len) == len;
 221     }
 222
 223     assert(len % (4 * sizeof(long)) == 0);
 224     len /= sizeof(long);
 225
 226     for (i = 0; i < len; i += 4) {
 227         d0 = data[i + 0];
 228         d1 = data[i + 1];
 229         d2 = data[i + 2];
 230         d3 = data[i + 3];
 231
 232         if (d0 || d1 || d2 || d3) {
 233             return false;
 234         }
 235     }
 236
 237     return true;
 238 }
 239
 240 #ifndef _WIN32
 241 /* Sets a specific flag */
 242 int fcntl_setfl(int fd, int flag)
 243 {
 244     int flags;
 245
 246     flags = fcntl(fd, F_GETFL);
 247     if (flags == -1)
 248         return -errno;
 249
 250     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 251         return -errno;
 252
 253     return 0;
 254 }
 255 #endif
 256
 257 static int64_t suffix_mul(char suffix, int64_t unit)
 258 {
 259     switch (qemu_toupper(suffix)) {
 260     case STRTOSZ_DEFSUFFIX_B:
 261         return 1;
 262     case STRTOSZ_DEFSUFFIX_KB:
 263         return unit;
 264     case STRTOSZ_DEFSUFFIX_MB:
 265         return unit * unit;
 266     case STRTOSZ_DEFSUFFIX_GB:
 267         return unit * unit * unit;
 268     case STRTOSZ_DEFSUFFIX_TB:
 269         return unit * unit * unit * unit;
 270     }
 271     return -1;
 272 }
 273
 274 /*
 275  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 276  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 277  * in *end, if not NULL. Return -ERANGE on overflow, Return -EINVAL on
 278  * other error.
 279  */
 280 int64_t strtosz_suffix_unit(const char *nptr, char **end,
 281                             const char default_suffix, int64_t unit)
 282 {
 283     int64_t retval = -EINVAL;
 284     char *endptr;
 285     unsigned char c;
 286     int mul_required = 0;
 287     double val, mul, integral, fraction;
 288
 289     errno = 0;
 290     val = strtod(nptr, &endptr);
 291     if (isnan(val) || endptr == nptr || errno != 0) {
 292         goto fail;
 293     }
 294     fraction = modf(val, &integral);
 295     if (fraction != 0) {
 296         mul_required = 1;
 297     }
 298     c = *endptr;
 299     mul = suffix_mul(c, unit);
 300     if (mul >= 0) {
 301         endptr++;
 302     } else {
 303         mul = suffix_mul(default_suffix, unit);
 304         assert(mul >= 0);
 305     }
 306     if (mul == 1 && mul_required) {
 307         goto fail;
 308     }
 309     if ((val * mul >= INT64_MAX) || val < 0) {
 310         retval = -ERANGE;
 311         goto fail;
 312     }
 313     retval = val * mul;
 314
 315 fail:
 316     if (end) {
 317         *end = endptr;
 318     }
 319
 320     return retval;
 321 }
 322
 323 int64_t strtosz_suffix(const char *nptr, char **end, const char default_suffix)
 324 {
 325     return strtosz_suffix_unit(nptr, end, default_suffix, 1024);
 326 }
 327
 328 int64_t strtosz(const char *nptr, char **end)
 329 {
 330     return strtosz_suffix(nptr, end, STRTOSZ_DEFSUFFIX_MB);
 331 }
 332
 333 /**
 334  * parse_uint:
 335  *
 336  * @s: String to parse
 337  * @value: Destination for parsed integer value
 338  * @endptr: Destination for pointer to first character not consumed
 339  * @base: integer base, between 2 and 36 inclusive, or 0
 340  *
 341  * Parse unsigned integer
 342  *
 343  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 344  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 345  *
 346  * If @s is null, or @base is invalid, or @s doesn't start with an
 347  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 348  * return -EINVAL.
 349  *
 350  * Set *@endptr to point right beyond the parsed integer (even if the integer
 351  * overflows or is negative, all digits will be parsed and *@endptr will
 352  * point right beyond them).
 353  *
 354  * If the integer is negative, set *@value to 0, and return -ERANGE.
 355  *
 356  * If the integer overflows unsigned long long, set *@value to
 357  * ULLONG_MAX, and return -ERANGE.
 358  *
 359  * Else, set *@value to the parsed integer, and return 0.
 360  */
 361 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 362                int base)
 363 {
 364     int r = 0;
 365     char *endp = (char *)s;
 366     unsigned long long val = 0;
 367
 368     if (!s) {
 369         r = -EINVAL;
 370         goto out;
 371     }
 372
 373     errno = 0;
 374     val = strtoull(s, &endp, base);
 375     if (errno) {
 376         r = -errno;
 377         goto out;
 378     }
 379
 380     if (endp == s) {
 381         r = -EINVAL;
 382         goto out;
 383     }
 384
 385     /* make sure we reject negative numbers: */
 386     while (isspace((unsigned char)*s)) {
 387         s++;
 388     }
 389     if (*s == '-') {
 390         val = 0;
 391         r = -ERANGE;
 392         goto out;
 393     }
 394
 395 out:
 396     *value = val;
 397     *endptr = endp;
 398     return r;
 399 }
 400
 401 /**
 402  * parse_uint_full:
 403  *
 404  * @s: String to parse
 405  * @value: Destination for parsed integer value
 406  * @base: integer base, between 2 and 36 inclusive, or 0
 407  *
 408  * Parse unsigned integer from entire string
 409  *
 410  * Have the same behavior of parse_uint(), but with an additional check
 411  * for additional data after the parsed number. If extra characters are present
 412  * after the parsed number, the function will return -EINVAL, and *@v will
 413  * be set to 0.
 414  */
 415 int parse_uint_full(const char *s, unsigned long long *value, int base)
 416 {
 417     char *endp;
 418     int r;
 419
 420     r = parse_uint(s, value, &endp, base);
 421     if (r < 0) {
 422         return r;
 423     }
 424     if (*endp) {
 425         *value = 0;
 426         return -EINVAL;
 427     }
 428
 429     return 0;
 430 }
 431
 432 int qemu_parse_fd(const char *param)
 433 {
 434     int fd;
 435     char *endptr = NULL;
 436
 437     fd = strtol(param, &endptr, 10);
 438     if (*endptr || (fd == 0 && param == endptr)) {
 439         return -1;
 440     }
 441     return fd;
 442 }
 443
 444 /* round down to the nearest power of 2*/
 445 int64_t pow2floor(int64_t value)
 446 {
 447     if (!is_power_of_2(value)) {
 448         value = 0x8000000000000000ULL >> clz64(value);
 449     }
 450     return value;
 451 }
 452
 453 /*
 454  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 455  * Input is limited to 14-bit numbers
 456  */
 457 int uleb128_encode_small(uint8_t *out, uint32_t n)
 458 {
 459     g_assert(n <= 0x3fff);
 460     if (n < 0x80) {
 461         *out++ = n;
 462         return 1;
 463     } else {
 464         *out++ = (n & 0x7f) | 0x80;
 465         *out++ = n >> 7;
 466         return 2;
 467     }
 468 }
 469
 470 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 471 {
 472     if (!(*in & 0x80)) {
 473         *n = *in++;
 474         return 1;
 475     } else {
 476         *n = *in++ & 0x7f;
 477         /* we exceed 14 bit number */
 478         if (*in & 0x80) {
 479             return -1;
 480         }
 481         *n |= *in++ << 7;
 482         return 2;
 483     }
 484 }
 485
 486 /*
 487  * helper to parse debug environment variables
 488  */
 489 int parse_debug_env(const char *name, int max, int initial)
 490 {
 491     char *debug_env = getenv(name);
 492     char *inv = NULL;
 493     int debug;
 494
 495     if (!debug_env) {
 496         return initial;
 497     }
 498     debug = strtol(debug_env, &inv, 10);
 499     if (inv == debug_env) {
 500         return initial;
 501     }
 502     if (debug < 0 || debug > max) {
 503         fprintf(stderr, "warning: %s not in [0, %d]", name, max);
 504         return initial;
 505     }
 506     return debug;
 507 }