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/osdep.h"
  25 #include "qemu-common.h"
  26 #include "qemu/host-utils.h"
  27 #include <math.h>
  28
  29 #include "qemu/sockets.h"
  30 #include "qemu/iov.h"
  31 #include "net/net.h"
  32 #include "qemu/cutils.h"
  33 #include "qemu/error-report.h"
  34
  35 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
  36 {
  37     int len = qemu_strnlen(str, buf_size);
  38     memcpy(buf, str, len);
  39     memset(buf + len, pad, buf_size - len);
  40 }
  41
  42 void pstrcpy(char *buf, int buf_size, const char *str)
  43 {
  44     int c;
  45     char *q = buf;
  46
  47     if (buf_size <= 0)
  48         return;
  49
  50     for(;;) {
  51         c = *str++;
  52         if (c == 0 || q >= buf + buf_size - 1)
  53             break;
  54         *q++ = c;
  55     }
  56     *q = '\0';
  57 }
  58
  59 /* strcat and truncate. */
  60 char *pstrcat(char *buf, int buf_size, const char *s)
  61 {
  62     int len;
  63     len = strlen(buf);
  64     if (len < buf_size)
  65         pstrcpy(buf + len, buf_size - len, s);
  66     return buf;
  67 }
  68
  69 int strstart(const char *str, const char *val, const char **ptr)
  70 {
  71     const char *p, *q;
  72     p = str;
  73     q = val;
  74     while (*q != '\0') {
  75         if (*p != *q)
  76             return 0;
  77         p++;
  78         q++;
  79     }
  80     if (ptr)
  81         *ptr = p;
  82     return 1;
  83 }
  84
  85 int stristart(const char *str, const char *val, const char **ptr)
  86 {
  87     const char *p, *q;
  88     p = str;
  89     q = val;
  90     while (*q != '\0') {
  91         if (qemu_toupper(*p) != qemu_toupper(*q))
  92             return 0;
  93         p++;
  94         q++;
  95     }
  96     if (ptr)
  97         *ptr = p;
  98     return 1;
  99 }
 100
 101 /* XXX: use host strnlen if available ? */
 102 int qemu_strnlen(const char *s, int max_len)
 103 {
 104     int i;
 105
 106     for(i = 0; i < max_len; i++) {
 107         if (s[i] == '\0') {
 108             break;
 109         }
 110     }
 111     return i;
 112 }
 113
 114 char *qemu_strsep(char **input, const char *delim)
 115 {
 116     char *result = *input;
 117     if (result != NULL) {
 118         char *p;
 119
 120         for (p = result; *p != '\0'; p++) {
 121             if (strchr(delim, *p)) {
 122                 break;
 123             }
 124         }
 125         if (*p == '\0') {
 126             *input = NULL;
 127         } else {
 128             *p = '\0';
 129             *input = p + 1;
 130         }
 131     }
 132     return result;
 133 }
 134
 135 time_t mktimegm(struct tm *tm)
 136 {
 137     time_t t;
 138     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 139     if (m < 3) {
 140         m += 12;
 141         y--;
 142     }
 143     t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
 144                  y / 400 - 719469);
 145     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 146     return t;
 147 }
 148
 149 /*
 150  * Make sure data goes on disk, but if possible do not bother to
 151  * write out the inode just for timestamp updates.
 152  *
 153  * Unfortunately even in 2009 many operating systems do not support
 154  * fdatasync and have to fall back to fsync.
 155  */
 156 int qemu_fdatasync(int fd)
 157 {
 158 #ifdef CONFIG_FDATASYNC
 159     return fdatasync(fd);
 160 #elif defined(_WIN64)
 161     /* TODO: Implement fsync for w64, too. */
 162     return NOERROR;
 163 #else
 164     return fsync(fd);
 165 #endif
 166 }
 167
 168 #ifndef _WIN32
 169 /* Sets a specific flag */
 170 int fcntl_setfl(int fd, int flag)
 171 {
 172     int flags;
 173
 174     flags = fcntl(fd, F_GETFL);
 175     if (flags == -1)
 176         return -errno;
 177
 178     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 179         return -errno;
 180
 181     return 0;
 182 }
 183 #endif
 184
 185 static int64_t suffix_mul(char suffix, int64_t unit)
 186 {
 187     switch (qemu_toupper(suffix)) {
 188     case 'B':
 189         return 1;
 190     case 'K':
 191         return unit;
 192     case 'M':
 193         return unit * unit;
 194     case 'G':
 195         return unit * unit * unit;
 196     case 'T':
 197         return unit * unit * unit * unit;
 198     case 'P':
 199         return unit * unit * unit * unit * unit;
 200     case 'E':
 201         return unit * unit * unit * unit * unit * unit;
 202     }
 203     return -1;
 204 }
 205
 206 /*
 207  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 208  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 209  * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
 210  * other error.
 211  */
 212 static int do_strtosz(const char *nptr, const char **end,
 213                       const char default_suffix, int64_t unit,
 214                       uint64_t *result)
 215 {
 216     int retval;
 217     const char *endptr;
 218     unsigned char c;
 219     int mul_required = 0;
 220     double val, mul, integral, fraction;
 221
 222     retval = qemu_strtod_finite(nptr, &endptr, &val);
 223     if (retval) {
 224         goto out;
 225     }
 226     fraction = modf(val, &integral);
 227     if (fraction != 0) {
 228         mul_required = 1;
 229     }
 230     c = *endptr;
 231     mul = suffix_mul(c, unit);
 232     if (mul >= 0) {
 233         endptr++;
 234     } else {
 235         mul = suffix_mul(default_suffix, unit);
 236         assert(mul >= 0);
 237     }
 238     if (mul == 1 && mul_required) {
 239         retval = -EINVAL;
 240         goto out;
 241     }
 242     /*
 243      * Values >= 0xfffffffffffffc00 overflow uint64_t after their trip
 244      * through double (53 bits of precision).
 245      */
 246     if ((val * mul >= 0xfffffffffffffc00) || val < 0) {
 247         retval = -ERANGE;
 248         goto out;
 249     }
 250     *result = val * mul;
 251     retval = 0;
 252
 253 out:
 254     if (end) {
 255         *end = endptr;
 256     } else if (*endptr) {
 257         retval = -EINVAL;
 258     }
 259
 260     return retval;
 261 }
 262
 263 int qemu_strtosz(const char *nptr, const char **end, uint64_t *result)
 264 {
 265     return do_strtosz(nptr, end, 'B', 1024, result);
 266 }
 267
 268 int qemu_strtosz_MiB(const char *nptr, const char **end, uint64_t *result)
 269 {
 270     return do_strtosz(nptr, end, 'M', 1024, result);
 271 }
 272
 273 int qemu_strtosz_metric(const char *nptr, const char **end, uint64_t *result)
 274 {
 275     return do_strtosz(nptr, end, 'B', 1000, result);
 276 }
 277
 278 /**
 279  * Helper function for error checking after strtol() and the like
 280  */
 281 static int check_strtox_error(const char *nptr, char *ep,
 282                               const char **endptr, int libc_errno)
 283 {
 284     assert(ep >= nptr);
 285     if (endptr) {
 286         *endptr = ep;
 287     }
 288
 289     /* Turn "no conversion" into an error */
 290     if (libc_errno == 0 && ep == nptr) {
 291         return -EINVAL;
 292     }
 293
 294     /* Fail when we're expected to consume the string, but didn't */
 295     if (!endptr && *ep) {
 296         return -EINVAL;
 297     }
 298
 299     return -libc_errno;
 300 }
 301
 302 /**
 303  * Convert string @nptr to an integer, and store it in @result.
 304  *
 305  * This is a wrapper around strtol() that is harder to misuse.
 306  * Semantics of @nptr, @endptr, @base match strtol() with differences
 307  * noted below.
 308  *
 309  * @nptr may be null, and no conversion is performed then.
 310  *
 311  * If no conversion is performed, store @nptr in *@endptr and return
 312  * -EINVAL.
 313  *
 314  * If @endptr is null, and the string isn't fully converted, return
 315  * -EINVAL.  This is the case when the pointer that would be stored in
 316  * a non-null @endptr points to a character other than '\0'.
 317  *
 318  * If the conversion overflows @result, store INT_MAX in @result,
 319  * and return -ERANGE.
 320  *
 321  * If the conversion underflows @result, store INT_MIN in @result,
 322  * and return -ERANGE.
 323  *
 324  * Else store the converted value in @result, and return zero.
 325  */
 326 int qemu_strtoi(const char *nptr, const char **endptr, int base,
 327                 int *result)
 328 {
 329     char *ep;
 330     long long lresult;
 331
 332     assert((unsigned) base <= 36 && base != 1);
 333     if (!nptr) {
 334         if (endptr) {
 335             *endptr = nptr;
 336         }
 337         return -EINVAL;
 338     }
 339
 340     errno = 0;
 341     lresult = strtoll(nptr, &ep, base);
 342     if (lresult < INT_MIN) {
 343         *result = INT_MIN;
 344         errno = ERANGE;
 345     } else if (lresult > INT_MAX) {
 346         *result = INT_MAX;
 347         errno = ERANGE;
 348     } else {
 349         *result = lresult;
 350     }
 351     return check_strtox_error(nptr, ep, endptr, errno);
 352 }
 353
 354 /**
 355  * Convert string @nptr to an unsigned integer, and store it in @result.
 356  *
 357  * This is a wrapper around strtoul() that is harder to misuse.
 358  * Semantics of @nptr, @endptr, @base match strtoul() with differences
 359  * noted below.
 360  *
 361  * @nptr may be null, and no conversion is performed then.
 362  *
 363  * If no conversion is performed, store @nptr in *@endptr and return
 364  * -EINVAL.
 365  *
 366  * If @endptr is null, and the string isn't fully converted, return
 367  * -EINVAL.  This is the case when the pointer that would be stored in
 368  * a non-null @endptr points to a character other than '\0'.
 369  *
 370  * If the conversion overflows @result, store UINT_MAX in @result,
 371  * and return -ERANGE.
 372  *
 373  * Else store the converted value in @result, and return zero.
 374  *
 375  * Note that a number with a leading minus sign gets converted without
 376  * the minus sign, checked for overflow (see above), then negated (in
 377  * @result's type).  This is exactly how strtoul() works.
 378  */
 379 int qemu_strtoui(const char *nptr, const char **endptr, int base,
 380                  unsigned int *result)
 381 {
 382     char *ep;
 383     long long lresult;
 384
 385     assert((unsigned) base <= 36 && base != 1);
 386     if (!nptr) {
 387         if (endptr) {
 388             *endptr = nptr;
 389         }
 390         return -EINVAL;
 391     }
 392
 393     errno = 0;
 394     lresult = strtoull(nptr, &ep, base);
 395
 396     /* Windows returns 1 for negative out-of-range values.  */
 397     if (errno == ERANGE) {
 398         *result = -1;
 399     } else {
 400         if (lresult > UINT_MAX) {
 401             *result = UINT_MAX;
 402             errno = ERANGE;
 403         } else if (lresult < INT_MIN) {
 404             *result = UINT_MAX;
 405             errno = ERANGE;
 406         } else {
 407             *result = lresult;
 408         }
 409     }
 410     return check_strtox_error(nptr, ep, endptr, errno);
 411 }
 412
 413 /**
 414  * Convert string @nptr to a long integer, and store it in @result.
 415  *
 416  * This is a wrapper around strtol() that is harder to misuse.
 417  * Semantics of @nptr, @endptr, @base match strtol() with differences
 418  * noted below.
 419  *
 420  * @nptr may be null, and no conversion is performed then.
 421  *
 422  * If no conversion is performed, store @nptr in *@endptr and return
 423  * -EINVAL.
 424  *
 425  * If @endptr is null, and the string isn't fully converted, return
 426  * -EINVAL.  This is the case when the pointer that would be stored in
 427  * a non-null @endptr points to a character other than '\0'.
 428  *
 429  * If the conversion overflows @result, store LONG_MAX in @result,
 430  * and return -ERANGE.
 431  *
 432  * If the conversion underflows @result, store LONG_MIN in @result,
 433  * and return -ERANGE.
 434  *
 435  * Else store the converted value in @result, and return zero.
 436  */
 437 int qemu_strtol(const char *nptr, const char **endptr, int base,
 438                 long *result)
 439 {
 440     char *ep;
 441
 442     assert((unsigned) base <= 36 && base != 1);
 443     if (!nptr) {
 444         if (endptr) {
 445             *endptr = nptr;
 446         }
 447         return -EINVAL;
 448     }
 449
 450     errno = 0;
 451     *result = strtol(nptr, &ep, base);
 452     return check_strtox_error(nptr, ep, endptr, errno);
 453 }
 454
 455 /**
 456  * Convert string @nptr to an unsigned long, and store it in @result.
 457  *
 458  * This is a wrapper around strtoul() that is harder to misuse.
 459  * Semantics of @nptr, @endptr, @base match strtoul() with differences
 460  * noted below.
 461  *
 462  * @nptr may be null, and no conversion is performed then.
 463  *
 464  * If no conversion is performed, store @nptr in *@endptr and return
 465  * -EINVAL.
 466  *
 467  * If @endptr is null, and the string isn't fully converted, return
 468  * -EINVAL.  This is the case when the pointer that would be stored in
 469  * a non-null @endptr points to a character other than '\0'.
 470  *
 471  * If the conversion overflows @result, store ULONG_MAX in @result,
 472  * and return -ERANGE.
 473  *
 474  * Else store the converted value in @result, and return zero.
 475  *
 476  * Note that a number with a leading minus sign gets converted without
 477  * the minus sign, checked for overflow (see above), then negated (in
 478  * @result's type).  This is exactly how strtoul() works.
 479  */
 480 int qemu_strtoul(const char *nptr, const char **endptr, int base,
 481                  unsigned long *result)
 482 {
 483     char *ep;
 484
 485     assert((unsigned) base <= 36 && base != 1);
 486     if (!nptr) {
 487         if (endptr) {
 488             *endptr = nptr;
 489         }
 490         return -EINVAL;
 491     }
 492
 493     errno = 0;
 494     *result = strtoul(nptr, &ep, base);
 495     /* Windows returns 1 for negative out-of-range values.  */
 496     if (errno == ERANGE) {
 497         *result = -1;
 498     }
 499     return check_strtox_error(nptr, ep, endptr, errno);
 500 }
 501
 502 /**
 503  * Convert string @nptr to an int64_t.
 504  *
 505  * Works like qemu_strtol(), except it stores INT64_MAX on overflow,
 506  * and INT_MIN on underflow.
 507  */
 508 int qemu_strtoi64(const char *nptr, const char **endptr, int base,
 509                  int64_t *result)
 510 {
 511     char *ep;
 512
 513     assert((unsigned) base <= 36 && base != 1);
 514     if (!nptr) {
 515         if (endptr) {
 516             *endptr = nptr;
 517         }
 518         return -EINVAL;
 519     }
 520
 521     errno = 0;
 522     /* FIXME This assumes int64_t is long long */
 523     *result = strtoll(nptr, &ep, base);
 524     return check_strtox_error(nptr, ep, endptr, errno);
 525 }
 526
 527 /**
 528  * Convert string @nptr to an uint64_t.
 529  *
 530  * Works like qemu_strtoul(), except it stores UINT64_MAX on overflow.
 531  */
 532 int qemu_strtou64(const char *nptr, const char **endptr, int base,
 533                   uint64_t *result)
 534 {
 535     char *ep;
 536
 537     assert((unsigned) base <= 36 && base != 1);
 538     if (!nptr) {
 539         if (endptr) {
 540             *endptr = nptr;
 541         }
 542         return -EINVAL;
 543     }
 544
 545     errno = 0;
 546     /* FIXME This assumes uint64_t is unsigned long long */
 547     *result = strtoull(nptr, &ep, base);
 548     /* Windows returns 1 for negative out-of-range values.  */
 549     if (errno == ERANGE) {
 550         *result = -1;
 551     }
 552     return check_strtox_error(nptr, ep, endptr, errno);
 553 }
 554
 555 /**
 556  * Convert string @nptr to a double.
 557   *
 558  * This is a wrapper around strtod() that is harder to misuse.
 559  * Semantics of @nptr and @endptr match strtod() with differences
 560  * noted below.
 561  *
 562  * @nptr may be null, and no conversion is performed then.
 563  *
 564  * If no conversion is performed, store @nptr in *@endptr and return
 565  * -EINVAL.
 566  *
 567  * If @endptr is null, and the string isn't fully converted, return
 568  * -EINVAL. This is the case when the pointer that would be stored in
 569  * a non-null @endptr points to a character other than '\0'.
 570  *
 571  * If the conversion overflows, store +/-HUGE_VAL in @result, depending
 572  * on the sign, and return -ERANGE.
 573  *
 574  * If the conversion underflows, store +/-0.0 in @result, depending on the
 575  * sign, and return -ERANGE.
 576  *
 577  * Else store the converted value in @result, and return zero.
 578  */
 579 int qemu_strtod(const char *nptr, const char **endptr, double *result)
 580 {
 581     char *ep;
 582
 583     if (!nptr) {
 584         if (endptr) {
 585             *endptr = nptr;
 586         }
 587         return -EINVAL;
 588     }
 589
 590     errno = 0;
 591     *result = strtod(nptr, &ep);
 592     return check_strtox_error(nptr, ep, endptr, errno);
 593 }
 594
 595 /**
 596  * Convert string @nptr to a finite double.
 597  *
 598  * Works like qemu_strtod(), except that "NaN" and "inf" are rejected
 599  * with -EINVAL and no conversion is performed.
 600  */
 601 int qemu_strtod_finite(const char *nptr, const char **endptr, double *result)
 602 {
 603     double tmp;
 604     int ret;
 605
 606     ret = qemu_strtod(nptr, endptr, &tmp);
 607     if (!ret && !isfinite(tmp)) {
 608         if (endptr) {
 609             *endptr = nptr;
 610         }
 611         ret = -EINVAL;
 612     }
 613
 614     if (ret != -EINVAL) {
 615         *result = tmp;
 616     }
 617     return ret;
 618 }
 619
 620 /**
 621  * Searches for the first occurrence of 'c' in 's', and returns a pointer
 622  * to the trailing null byte if none was found.
 623  */
 624 #ifndef HAVE_STRCHRNUL
 625 const char *qemu_strchrnul(const char *s, int c)
 626 {
 627     const char *e = strchr(s, c);
 628     if (!e) {
 629         e = s + strlen(s);
 630     }
 631     return e;
 632 }
 633 #endif
 634
 635 /**
 636  * parse_uint:
 637  *
 638  * @s: String to parse
 639  * @value: Destination for parsed integer value
 640  * @endptr: Destination for pointer to first character not consumed
 641  * @base: integer base, between 2 and 36 inclusive, or 0
 642  *
 643  * Parse unsigned integer
 644  *
 645  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 646  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 647  *
 648  * If @s is null, or @base is invalid, or @s doesn't start with an
 649  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 650  * return -EINVAL.
 651  *
 652  * Set *@endptr to point right beyond the parsed integer (even if the integer
 653  * overflows or is negative, all digits will be parsed and *@endptr will
 654  * point right beyond them).
 655  *
 656  * If the integer is negative, set *@value to 0, and return -ERANGE.
 657  *
 658  * If the integer overflows unsigned long long, set *@value to
 659  * ULLONG_MAX, and return -ERANGE.
 660  *
 661  * Else, set *@value to the parsed integer, and return 0.
 662  */
 663 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 664                int base)
 665 {
 666     int r = 0;
 667     char *endp = (char *)s;
 668     unsigned long long val = 0;
 669
 670     assert((unsigned) base <= 36 && base != 1);
 671     if (!s) {
 672         r = -EINVAL;
 673         goto out;
 674     }
 675
 676     errno = 0;
 677     val = strtoull(s, &endp, base);
 678     if (errno) {
 679         r = -errno;
 680         goto out;
 681     }
 682
 683     if (endp == s) {
 684         r = -EINVAL;
 685         goto out;
 686     }
 687
 688     /* make sure we reject negative numbers: */
 689     while (isspace((unsigned char)*s)) {
 690         s++;
 691     }
 692     if (*s == '-') {
 693         val = 0;
 694         r = -ERANGE;
 695         goto out;
 696     }
 697
 698 out:
 699     *value = val;
 700     *endptr = endp;
 701     return r;
 702 }
 703
 704 /**
 705  * parse_uint_full:
 706  *
 707  * @s: String to parse
 708  * @value: Destination for parsed integer value
 709  * @base: integer base, between 2 and 36 inclusive, or 0
 710  *
 711  * Parse unsigned integer from entire string
 712  *
 713  * Have the same behavior of parse_uint(), but with an additional check
 714  * for additional data after the parsed number. If extra characters are present
 715  * after the parsed number, the function will return -EINVAL, and *@v will
 716  * be set to 0.
 717  */
 718 int parse_uint_full(const char *s, unsigned long long *value, int base)
 719 {
 720     char *endp;
 721     int r;
 722
 723     r = parse_uint(s, value, &endp, base);
 724     if (r < 0) {
 725         return r;
 726     }
 727     if (*endp) {
 728         *value = 0;
 729         return -EINVAL;
 730     }
 731
 732     return 0;
 733 }
 734
 735 int qemu_parse_fd(const char *param)
 736 {
 737     long fd;
 738     char *endptr;
 739
 740     errno = 0;
 741     fd = strtol(param, &endptr, 10);
 742     if (param == endptr /* no conversion performed */                    ||
 743         errno != 0      /* not representable as long; possibly others */ ||
 744         *endptr != '\0' /* final string not empty */                     ||
 745         fd < 0          /* invalid as file descriptor */                 ||
 746         fd > INT_MAX    /* not representable as int */) {
 747         return -1;
 748     }
 749     return fd;
 750 }
 751
 752 /*
 753  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 754  * Input is limited to 14-bit numbers
 755  */
 756 int uleb128_encode_small(uint8_t *out, uint32_t n)
 757 {
 758     g_assert(n <= 0x3fff);
 759     if (n < 0x80) {
 760         *out++ = n;
 761         return 1;
 762     } else {
 763         *out++ = (n & 0x7f) | 0x80;
 764         *out++ = n >> 7;
 765         return 2;
 766     }
 767 }
 768
 769 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 770 {
 771     if (!(*in & 0x80)) {
 772         *n = *in++;
 773         return 1;
 774     } else {
 775         *n = *in++ & 0x7f;
 776         /* we exceed 14 bit number */
 777         if (*in & 0x80) {
 778             return -1;
 779         }
 780         *n |= *in++ << 7;
 781         return 2;
 782     }
 783 }
 784
 785 /*
 786  * helper to parse debug environment variables
 787  */
 788 int parse_debug_env(const char *name, int max, int initial)
 789 {
 790     char *debug_env = getenv(name);
 791     char *inv = NULL;
 792     long debug;
 793
 794     if (!debug_env) {
 795         return initial;
 796     }
 797     errno = 0;
 798     debug = strtol(debug_env, &inv, 10);
 799     if (inv == debug_env) {
 800         return initial;
 801     }
 802     if (debug < 0 || debug > max || errno != 0) {
 803         warn_report("%s not in [0, %d]", name, max);
 804         return initial;
 805     }
 806     return debug;
 807 }
 808
 809 /*
 810  * Helper to print ethernet mac address
 811  */
 812 const char *qemu_ether_ntoa(const MACAddr *mac)
 813 {
 814     static char ret[18];
 815
 816     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 817              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 818
 819     return ret;
 820 }
 821
 822 /*
 823  * Return human readable string for size @val.
 824  * @val can be anything that uint64_t allows (no more than "16 EiB").
 825  * Use IEC binary units like KiB, MiB, and so forth.
 826  * Caller is responsible for passing it to g_free().
 827  */
 828 char *size_to_str(uint64_t val)
 829 {
 830     static const char *suffixes[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei" };
 831     unsigned long div;
 832     int i;
 833
 834     /*
 835      * The exponent (returned in i) minus one gives us
 836      * floor(log2(val * 1024 / 1000).  The correction makes us
 837      * switch to the higher power when the integer part is >= 1000.
 838      * (see e41b509d68afb1f for more info)
 839      */
 840     frexp(val / (1000.0 / 1024.0), &i);
 841     i = (i - 1) / 10;
 842     div = 1ULL << (i * 10);
 843
 844     return g_strdup_printf("%0.3g %sB", (double)val / div, suffixes[i]);
 845 }
 846
 847 int qemu_pstrcmp0(const char **str1, const char **str2)
 848 {
 849     return g_strcmp0(*str1, *str2);
 850 }