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
  25 #include "qemu/osdep.h"
  26 #include "qemu/host-utils.h"
  27 #include <math.h>
  28
  29 #include "qemu-common.h"
  30 #include "qemu/sockets.h"
  31 #include "qemu/iov.h"
  32 #include "net/net.h"
  33 #include "qemu/ctype.h"
  34 #include "qemu/cutils.h"
  35 #include "qemu/error-report.h"
  36
  37 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
  38 {
  39     int len = qemu_strnlen(str, buf_size);
  40     memcpy(buf, str, len);
  41     memset(buf + len, pad, buf_size - len);
  42 }
  43
  44 void pstrcpy(char *buf, int buf_size, const char *str)
  45 {
  46     int c;
  47     char *q = buf;
  48
  49     if (buf_size <= 0)
  50         return;
  51
  52     for(;;) {
  53         c = *str++;
  54         if (c == 0 || q >= buf + buf_size - 1)
  55             break;
  56         *q++ = c;
  57     }
  58     *q = '\0';
  59 }
  60
  61 /* strcat and truncate. */
  62 char *pstrcat(char *buf, int buf_size, const char *s)
  63 {
  64     int len;
  65     len = strlen(buf);
  66     if (len < buf_size)
  67         pstrcpy(buf + len, buf_size - len, s);
  68     return buf;
  69 }
  70
  71 int strstart(const char *str, const char *val, const char **ptr)
  72 {
  73     const char *p, *q;
  74     p = str;
  75     q = val;
  76     while (*q != '\0') {
  77         if (*p != *q)
  78             return 0;
  79         p++;
  80         q++;
  81     }
  82     if (ptr)
  83         *ptr = p;
  84     return 1;
  85 }
  86
  87 int stristart(const char *str, const char *val, const char **ptr)
  88 {
  89     const char *p, *q;
  90     p = str;
  91     q = val;
  92     while (*q != '\0') {
  93         if (qemu_toupper(*p) != qemu_toupper(*q))
  94             return 0;
  95         p++;
  96         q++;
  97     }
  98     if (ptr)
  99         *ptr = p;
 100     return 1;
 101 }
 102
 103 /* XXX: use host strnlen if available ? */
 104 int qemu_strnlen(const char *s, int max_len)
 105 {
 106     int i;
 107
 108     for(i = 0; i < max_len; i++) {
 109         if (s[i] == '\0') {
 110             break;
 111         }
 112     }
 113     return i;
 114 }
 115
 116 char *qemu_strsep(char **input, const char *delim)
 117 {
 118     char *result = *input;
 119     if (result != NULL) {
 120         char *p;
 121
 122         for (p = result; *p != '\0'; p++) {
 123             if (strchr(delim, *p)) {
 124                 break;
 125             }
 126         }
 127         if (*p == '\0') {
 128             *input = NULL;
 129         } else {
 130             *p = '\0';
 131             *input = p + 1;
 132         }
 133     }
 134     return result;
 135 }
 136
 137 time_t mktimegm(struct tm *tm)
 138 {
 139     time_t t;
 140     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 141     if (m < 3) {
 142         m += 12;
 143         y--;
 144     }
 145     t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
 146                  y / 400 - 719469);
 147     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 148     return t;
 149 }
 150
 151 /*
 152  * Make sure data goes on disk, but if possible do not bother to
 153  * write out the inode just for timestamp updates.
 154  *
 155  * Unfortunately even in 2009 many operating systems do not support
 156  * fdatasync and have to fall back to fsync.
 157  */
 158 int qemu_fdatasync(int fd)
 159 {
 160 #ifdef CONFIG_FDATASYNC
 161     return fdatasync(fd);
 162 #else
 163     return fsync(fd);
 164 #endif
 165 }
 166
 167 #ifndef _WIN32
 168 /* Sets a specific flag */
 169 int fcntl_setfl(int fd, int flag)
 170 {
 171     int flags;
 172
 173     flags = fcntl(fd, F_GETFL);
 174     if (flags == -1)
 175         return -errno;
 176
 177     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 178         return -errno;
 179
 180     return 0;
 181 }
 182 #endif
 183
 184 static int64_t suffix_mul(char suffix, int64_t unit)
 185 {
 186     switch (qemu_toupper(suffix)) {
 187     case 'B':
 188         return 1;
 189     case 'K':
 190         return unit;
 191     case 'M':
 192         return unit * unit;
 193     case 'G':
 194         return unit * unit * unit;
 195     case 'T':
 196         return unit * unit * unit * unit;
 197     case 'P':
 198         return unit * unit * unit * unit * unit;
 199     case 'E':
 200         return unit * unit * unit * unit * unit * unit;
 201     }
 202     return -1;
 203 }
 204
 205 /*
 206  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 207  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 208  * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
 209  * other error.
 210  */
 211 static int do_strtosz(const char *nptr, const char **end,
 212                       const char default_suffix, int64_t unit,
 213                       uint64_t *result)
 214 {
 215     int retval;
 216     const char *endptr;
 217     unsigned char c;
 218     int mul_required = 0;
 219     double val, mul, integral, fraction;
 220
 221     retval = qemu_strtod_finite(nptr, &endptr, &val);
 222     if (retval) {
 223         goto out;
 224     }
 225     fraction = modf(val, &integral);
 226     if (fraction != 0) {
 227         mul_required = 1;
 228     }
 229     c = *endptr;
 230     mul = suffix_mul(c, unit);
 231     if (mul >= 0) {
 232         endptr++;
 233     } else {
 234         mul = suffix_mul(default_suffix, unit);
 235         assert(mul >= 0);
 236     }
 237     if (mul == 1 && mul_required) {
 238         retval = -EINVAL;
 239         goto out;
 240     }
 241     /*
 242      * Values near UINT64_MAX overflow to 2**64 when converting to double
 243      * precision.  Compare against the maximum representable double precision
 244      * value below 2**64, computed as "the next value after 2**64 (0x1p64) in
 245      * the direction of 0".
 246      */
 247     if ((val * mul > nextafter(0x1p64, 0)) || val < 0) {
 248         retval = -ERANGE;
 249         goto out;
 250     }
 251     *result = val * mul;
 252     retval = 0;
 253
 254 out:
 255     if (end) {
 256         *end = endptr;
 257     } else if (*endptr) {
 258         retval = -EINVAL;
 259     }
 260
 261     return retval;
 262 }
 263
 264 int qemu_strtosz(const char *nptr, const char **end, uint64_t *result)
 265 {
 266     return do_strtosz(nptr, end, 'B', 1024, result);
 267 }
 268
 269 int qemu_strtosz_MiB(const char *nptr, const char **end, uint64_t *result)
 270 {
 271     return do_strtosz(nptr, end, 'M', 1024, result);
 272 }
 273
 274 int qemu_strtosz_metric(const char *nptr, const char **end, uint64_t *result)
 275 {
 276     return do_strtosz(nptr, end, 'B', 1000, result);
 277 }
 278
 279 /**
 280  * Helper function for error checking after strtol() and the like
 281  */
 282 static int check_strtox_error(const char *nptr, char *ep,
 283                               const char **endptr, int libc_errno)
 284 {
 285     assert(ep >= nptr);
 286     if (endptr) {
 287         *endptr = ep;
 288     }
 289
 290     /* Turn "no conversion" into an error */
 291     if (libc_errno == 0 && ep == nptr) {
 292         return -EINVAL;
 293     }
 294
 295     /* Fail when we're expected to consume the string, but didn't */
 296     if (!endptr && *ep) {
 297         return -EINVAL;
 298     }
 299
 300     return -libc_errno;
 301 }
 302
 303 /**
 304  * Convert string @nptr to an integer, and store it in @result.
 305  *
 306  * This is a wrapper around strtol() that is harder to misuse.
 307  * Semantics of @nptr, @endptr, @base match strtol() with differences
 308  * noted below.
 309  *
 310  * @nptr may be null, and no conversion is performed then.
 311  *
 312  * If no conversion is performed, store @nptr in *@endptr and return
 313  * -EINVAL.
 314  *
 315  * If @endptr is null, and the string isn't fully converted, return
 316  * -EINVAL.  This is the case when the pointer that would be stored in
 317  * a non-null @endptr points to a character other than '\0'.
 318  *
 319  * If the conversion overflows @result, store INT_MAX in @result,
 320  * and return -ERANGE.
 321  *
 322  * If the conversion underflows @result, store INT_MIN in @result,
 323  * and return -ERANGE.
 324  *
 325  * Else store the converted value in @result, and return zero.
 326  */
 327 int qemu_strtoi(const char *nptr, const char **endptr, int base,
 328                 int *result)
 329 {
 330     char *ep;
 331     long long lresult;
 332
 333     assert((unsigned) base <= 36 && base != 1);
 334     if (!nptr) {
 335         if (endptr) {
 336             *endptr = nptr;
 337         }
 338         return -EINVAL;
 339     }
 340
 341     errno = 0;
 342     lresult = strtoll(nptr, &ep, base);
 343     if (lresult < INT_MIN) {
 344         *result = INT_MIN;
 345         errno = ERANGE;
 346     } else if (lresult > INT_MAX) {
 347         *result = INT_MAX;
 348         errno = ERANGE;
 349     } else {
 350         *result = lresult;
 351     }
 352     return check_strtox_error(nptr, ep, endptr, errno);
 353 }
 354
 355 /**
 356  * Convert string @nptr to an unsigned integer, and store it in @result.
 357  *
 358  * This is a wrapper around strtoul() that is harder to misuse.
 359  * Semantics of @nptr, @endptr, @base match strtoul() with differences
 360  * noted below.
 361  *
 362  * @nptr may be null, and no conversion is performed then.
 363  *
 364  * If no conversion is performed, store @nptr in *@endptr and return
 365  * -EINVAL.
 366  *
 367  * If @endptr is null, and the string isn't fully converted, return
 368  * -EINVAL.  This is the case when the pointer that would be stored in
 369  * a non-null @endptr points to a character other than '\0'.
 370  *
 371  * If the conversion overflows @result, store UINT_MAX in @result,
 372  * and return -ERANGE.
 373  *
 374  * Else store the converted value in @result, and return zero.
 375  *
 376  * Note that a number with a leading minus sign gets converted without
 377  * the minus sign, checked for overflow (see above), then negated (in
 378  * @result's type).  This is exactly how strtoul() works.
 379  */
 380 int qemu_strtoui(const char *nptr, const char **endptr, int base,
 381                  unsigned int *result)
 382 {
 383     char *ep;
 384     long long lresult;
 385
 386     assert((unsigned) base <= 36 && base != 1);
 387     if (!nptr) {
 388         if (endptr) {
 389             *endptr = nptr;
 390         }
 391         return -EINVAL;
 392     }
 393
 394     errno = 0;
 395     lresult = strtoull(nptr, &ep, base);
 396
 397     /* Windows returns 1 for negative out-of-range values.  */
 398     if (errno == ERANGE) {
 399         *result = -1;
 400     } else {
 401         if (lresult > UINT_MAX) {
 402             *result = UINT_MAX;
 403             errno = ERANGE;
 404         } else if (lresult < INT_MIN) {
 405             *result = UINT_MAX;
 406             errno = ERANGE;
 407         } else {
 408             *result = lresult;
 409         }
 410     }
 411     return check_strtox_error(nptr, ep, endptr, errno);
 412 }
 413
 414 /**
 415  * Convert string @nptr to a long integer, and store it in @result.
 416  *
 417  * This is a wrapper around strtol() that is harder to misuse.
 418  * Semantics of @nptr, @endptr, @base match strtol() with differences
 419  * noted below.
 420  *
 421  * @nptr may be null, and no conversion is performed then.
 422  *
 423  * If no conversion is performed, store @nptr in *@endptr and return
 424  * -EINVAL.
 425  *
 426  * If @endptr is null, and the string isn't fully converted, return
 427  * -EINVAL.  This is the case when the pointer that would be stored in
 428  * a non-null @endptr points to a character other than '\0'.
 429  *
 430  * If the conversion overflows @result, store LONG_MAX in @result,
 431  * and return -ERANGE.
 432  *
 433  * If the conversion underflows @result, store LONG_MIN in @result,
 434  * and return -ERANGE.
 435  *
 436  * Else store the converted value in @result, and return zero.
 437  */
 438 int qemu_strtol(const char *nptr, const char **endptr, int base,
 439                 long *result)
 440 {
 441     char *ep;
 442
 443     assert((unsigned) base <= 36 && base != 1);
 444     if (!nptr) {
 445         if (endptr) {
 446             *endptr = nptr;
 447         }
 448         return -EINVAL;
 449     }
 450
 451     errno = 0;
 452     *result = strtol(nptr, &ep, base);
 453     return check_strtox_error(nptr, ep, endptr, errno);
 454 }
 455
 456 /**
 457  * Convert string @nptr to an unsigned long, and store it in @result.
 458  *
 459  * This is a wrapper around strtoul() that is harder to misuse.
 460  * Semantics of @nptr, @endptr, @base match strtoul() with differences
 461  * noted below.
 462  *
 463  * @nptr may be null, and no conversion is performed then.
 464  *
 465  * If no conversion is performed, store @nptr in *@endptr and return
 466  * -EINVAL.
 467  *
 468  * If @endptr is null, and the string isn't fully converted, return
 469  * -EINVAL.  This is the case when the pointer that would be stored in
 470  * a non-null @endptr points to a character other than '\0'.
 471  *
 472  * If the conversion overflows @result, store ULONG_MAX in @result,
 473  * and return -ERANGE.
 474  *
 475  * Else store the converted value in @result, and return zero.
 476  *
 477  * Note that a number with a leading minus sign gets converted without
 478  * the minus sign, checked for overflow (see above), then negated (in
 479  * @result's type).  This is exactly how strtoul() works.
 480  */
 481 int qemu_strtoul(const char *nptr, const char **endptr, int base,
 482                  unsigned long *result)
 483 {
 484     char *ep;
 485
 486     assert((unsigned) base <= 36 && base != 1);
 487     if (!nptr) {
 488         if (endptr) {
 489             *endptr = nptr;
 490         }
 491         return -EINVAL;
 492     }
 493
 494     errno = 0;
 495     *result = strtoul(nptr, &ep, base);
 496     /* Windows returns 1 for negative out-of-range values.  */
 497     if (errno == ERANGE) {
 498         *result = -1;
 499     }
 500     return check_strtox_error(nptr, ep, endptr, errno);
 501 }
 502
 503 /**
 504  * Convert string @nptr to an int64_t.
 505  *
 506  * Works like qemu_strtol(), except it stores INT64_MAX on overflow,
 507  * and INT_MIN on underflow.
 508  */
 509 int qemu_strtoi64(const char *nptr, const char **endptr, int base,
 510                  int64_t *result)
 511 {
 512     char *ep;
 513
 514     assert((unsigned) base <= 36 && base != 1);
 515     if (!nptr) {
 516         if (endptr) {
 517             *endptr = nptr;
 518         }
 519         return -EINVAL;
 520     }
 521
 522     errno = 0;
 523     /* FIXME This assumes int64_t is long long */
 524     *result = strtoll(nptr, &ep, base);
 525     return check_strtox_error(nptr, ep, endptr, errno);
 526 }
 527
 528 /**
 529  * Convert string @nptr to an uint64_t.
 530  *
 531  * Works like qemu_strtoul(), except it stores UINT64_MAX on overflow.
 532  */
 533 int qemu_strtou64(const char *nptr, const char **endptr, int base,
 534                   uint64_t *result)
 535 {
 536     char *ep;
 537
 538     assert((unsigned) base <= 36 && base != 1);
 539     if (!nptr) {
 540         if (endptr) {
 541             *endptr = nptr;
 542         }
 543         return -EINVAL;
 544     }
 545
 546     errno = 0;
 547     /* FIXME This assumes uint64_t is unsigned long long */
 548     *result = strtoull(nptr, &ep, base);
 549     /* Windows returns 1 for negative out-of-range values.  */
 550     if (errno == ERANGE) {
 551         *result = -1;
 552     }
 553     return check_strtox_error(nptr, ep, endptr, errno);
 554 }
 555
 556 /**
 557  * Convert string @nptr to a double.
 558   *
 559  * This is a wrapper around strtod() that is harder to misuse.
 560  * Semantics of @nptr and @endptr match strtod() with differences
 561  * noted below.
 562  *
 563  * @nptr may be null, and no conversion is performed then.
 564  *
 565  * If no conversion is performed, store @nptr in *@endptr and return
 566  * -EINVAL.
 567  *
 568  * If @endptr is null, and the string isn't fully converted, return
 569  * -EINVAL. This is the case when the pointer that would be stored in
 570  * a non-null @endptr points to a character other than '\0'.
 571  *
 572  * If the conversion overflows, store +/-HUGE_VAL in @result, depending
 573  * on the sign, and return -ERANGE.
 574  *
 575  * If the conversion underflows, store +/-0.0 in @result, depending on the
 576  * sign, and return -ERANGE.
 577  *
 578  * Else store the converted value in @result, and return zero.
 579  */
 580 int qemu_strtod(const char *nptr, const char **endptr, double *result)
 581 {
 582     char *ep;
 583
 584     if (!nptr) {
 585         if (endptr) {
 586             *endptr = nptr;
 587         }
 588         return -EINVAL;
 589     }
 590
 591     errno = 0;
 592     *result = strtod(nptr, &ep);
 593     return check_strtox_error(nptr, ep, endptr, errno);
 594 }
 595
 596 /**
 597  * Convert string @nptr to a finite double.
 598  *
 599  * Works like qemu_strtod(), except that "NaN" and "inf" are rejected
 600  * with -EINVAL and no conversion is performed.
 601  */
 602 int qemu_strtod_finite(const char *nptr, const char **endptr, double *result)
 603 {
 604     double tmp;
 605     int ret;
 606
 607     ret = qemu_strtod(nptr, endptr, &tmp);
 608     if (!ret && !isfinite(tmp)) {
 609         if (endptr) {
 610             *endptr = nptr;
 611         }
 612         ret = -EINVAL;
 613     }
 614
 615     if (ret != -EINVAL) {
 616         *result = tmp;
 617     }
 618     return ret;
 619 }
 620
 621 /**
 622  * Searches for the first occurrence of 'c' in 's', and returns a pointer
 623  * to the trailing null byte if none was found.
 624  */
 625 #ifndef HAVE_STRCHRNUL
 626 const char *qemu_strchrnul(const char *s, int c)
 627 {
 628     const char *e = strchr(s, c);
 629     if (!e) {
 630         e = s + strlen(s);
 631     }
 632     return e;
 633 }
 634 #endif
 635
 636 /**
 637  * parse_uint:
 638  *
 639  * @s: String to parse
 640  * @value: Destination for parsed integer value
 641  * @endptr: Destination for pointer to first character not consumed
 642  * @base: integer base, between 2 and 36 inclusive, or 0
 643  *
 644  * Parse unsigned integer
 645  *
 646  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 647  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 648  *
 649  * If @s is null, or @base is invalid, or @s doesn't start with an
 650  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 651  * return -EINVAL.
 652  *
 653  * Set *@endptr to point right beyond the parsed integer (even if the integer
 654  * overflows or is negative, all digits will be parsed and *@endptr will
 655  * point right beyond them).
 656  *
 657  * If the integer is negative, set *@value to 0, and return -ERANGE.
 658  *
 659  * If the integer overflows unsigned long long, set *@value to
 660  * ULLONG_MAX, and return -ERANGE.
 661  *
 662  * Else, set *@value to the parsed integer, and return 0.
 663  */
 664 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 665                int base)
 666 {
 667     int r = 0;
 668     char *endp = (char *)s;
 669     unsigned long long val = 0;
 670
 671     assert((unsigned) base <= 36 && base != 1);
 672     if (!s) {
 673         r = -EINVAL;
 674         goto out;
 675     }
 676
 677     errno = 0;
 678     val = strtoull(s, &endp, base);
 679     if (errno) {
 680         r = -errno;
 681         goto out;
 682     }
 683
 684     if (endp == s) {
 685         r = -EINVAL;
 686         goto out;
 687     }
 688
 689     /* make sure we reject negative numbers: */
 690     while (qemu_isspace(*s)) {
 691         s++;
 692     }
 693     if (*s == '-') {
 694         val = 0;
 695         r = -ERANGE;
 696         goto out;
 697     }
 698
 699 out:
 700     *value = val;
 701     *endptr = endp;
 702     return r;
 703 }
 704
 705 /**
 706  * parse_uint_full:
 707  *
 708  * @s: String to parse
 709  * @value: Destination for parsed integer value
 710  * @base: integer base, between 2 and 36 inclusive, or 0
 711  *
 712  * Parse unsigned integer from entire string
 713  *
 714  * Have the same behavior of parse_uint(), but with an additional check
 715  * for additional data after the parsed number. If extra characters are present
 716  * after the parsed number, the function will return -EINVAL, and *@v will
 717  * be set to 0.
 718  */
 719 int parse_uint_full(const char *s, unsigned long long *value, int base)
 720 {
 721     char *endp;
 722     int r;
 723
 724     r = parse_uint(s, value, &endp, base);
 725     if (r < 0) {
 726         return r;
 727     }
 728     if (*endp) {
 729         *value = 0;
 730         return -EINVAL;
 731     }
 732
 733     return 0;
 734 }
 735
 736 int qemu_parse_fd(const char *param)
 737 {
 738     long fd;
 739     char *endptr;
 740
 741     errno = 0;
 742     fd = strtol(param, &endptr, 10);
 743     if (param == endptr /* no conversion performed */                    ||
 744         errno != 0      /* not representable as long; possibly others */ ||
 745         *endptr != '\0' /* final string not empty */                     ||
 746         fd < 0          /* invalid as file descriptor */                 ||
 747         fd > INT_MAX    /* not representable as int */) {
 748         return -1;
 749     }
 750     return fd;
 751 }
 752
 753 /*
 754  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 755  * Input is limited to 14-bit numbers
 756  */
 757 int uleb128_encode_small(uint8_t *out, uint32_t n)
 758 {
 759     g_assert(n <= 0x3fff);
 760     if (n < 0x80) {
 761         *out = n;
 762         return 1;
 763     } else {
 764         *out++ = (n & 0x7f) | 0x80;
 765         *out = n >> 7;
 766         return 2;
 767     }
 768 }
 769
 770 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 771 {
 772     if (!(*in & 0x80)) {
 773         *n = *in;
 774         return 1;
 775     } else {
 776         *n = *in++ & 0x7f;
 777         /* we exceed 14 bit number */
 778         if (*in & 0x80) {
 779             return -1;
 780         }
 781         *n |= *in << 7;
 782         return 2;
 783     }
 784 }
 785
 786 /*
 787  * helper to parse debug environment variables
 788  */
 789 int parse_debug_env(const char *name, int max, int initial)
 790 {
 791     char *debug_env = getenv(name);
 792     char *inv = NULL;
 793     long debug;
 794
 795     if (!debug_env) {
 796         return initial;
 797     }
 798     errno = 0;
 799     debug = strtol(debug_env, &inv, 10);
 800     if (inv == debug_env) {
 801         return initial;
 802     }
 803     if (debug < 0 || debug > max || errno != 0) {
 804         warn_report("%s not in [0, %d]", name, max);
 805         return initial;
 806     }
 807     return debug;
 808 }
 809
 810 /*
 811  * Helper to print ethernet mac address
 812  */
 813 const char *qemu_ether_ntoa(const MACAddr *mac)
 814 {
 815     static char ret[18];
 816
 817     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 818              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 819
 820     return ret;
 821 }
 822
 823 /*
 824  * Return human readable string for size @val.
 825  * @val can be anything that uint64_t allows (no more than "16 EiB").
 826  * Use IEC binary units like KiB, MiB, and so forth.
 827  * Caller is responsible for passing it to g_free().
 828  */
 829 char *size_to_str(uint64_t val)
 830 {
 831     static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
 832     uint64_t div;
 833     int i;
 834
 835     /*
 836      * The exponent (returned in i) minus one gives us
 837      * floor(log2(val * 1024 / 1000).  The correction makes us
 838      * switch to the higher power when the integer part is >= 1000.
 839      * (see e41b509d68afb1f for more info)
 840      */
 841     frexp(val / (1000.0 / 1024.0), &i);
 842     i = (i - 1) / 10;
 843     div = 1ULL << (i * 10);
 844
 845     return g_strdup_printf("%0.3g %sB", (double)val / div, suffixes[i]);
 846 }
 847
 848 int qemu_pstrcmp0(const char **str1, const char **str2)
 849 {
 850     return g_strcmp0(*str1, *str2);
 851 }