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