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
  34 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
  35 {
  36     int len = qemu_strnlen(str, buf_size);
  37     memcpy(buf, str, len);
  38     memset(buf + len, pad, buf_size - len);
  39 }
  40
  41 void pstrcpy(char *buf, int buf_size, const char *str)
  42 {
  43     int c;
  44     char *q = buf;
  45
  46     if (buf_size <= 0)
  47         return;
  48
  49     for(;;) {
  50         c = *str++;
  51         if (c == 0 || q >= buf + buf_size - 1)
  52             break;
  53         *q++ = c;
  54     }
  55     *q = '\0';
  56 }
  57
  58 /* strcat and truncate. */
  59 char *pstrcat(char *buf, int buf_size, const char *s)
  60 {
  61     int len;
  62     len = strlen(buf);
  63     if (len < buf_size)
  64         pstrcpy(buf + len, buf_size - len, s);
  65     return buf;
  66 }
  67
  68 int strstart(const char *str, const char *val, const char **ptr)
  69 {
  70     const char *p, *q;
  71     p = str;
  72     q = val;
  73     while (*q != '\0') {
  74         if (*p != *q)
  75             return 0;
  76         p++;
  77         q++;
  78     }
  79     if (ptr)
  80         *ptr = p;
  81     return 1;
  82 }
  83
  84 int stristart(const char *str, const char *val, const char **ptr)
  85 {
  86     const char *p, *q;
  87     p = str;
  88     q = val;
  89     while (*q != '\0') {
  90         if (qemu_toupper(*p) != qemu_toupper(*q))
  91             return 0;
  92         p++;
  93         q++;
  94     }
  95     if (ptr)
  96         *ptr = p;
  97     return 1;
  98 }
  99
 100 /* XXX: use host strnlen if available ? */
 101 int qemu_strnlen(const char *s, int max_len)
 102 {
 103     int i;
 104
 105     for(i = 0; i < max_len; i++) {
 106         if (s[i] == '\0') {
 107             break;
 108         }
 109     }
 110     return i;
 111 }
 112
 113 char *qemu_strsep(char **input, const char *delim)
 114 {
 115     char *result = *input;
 116     if (result != NULL) {
 117         char *p;
 118
 119         for (p = result; *p != '\0'; p++) {
 120             if (strchr(delim, *p)) {
 121                 break;
 122             }
 123         }
 124         if (*p == '\0') {
 125             *input = NULL;
 126         } else {
 127             *p = '\0';
 128             *input = p + 1;
 129         }
 130     }
 131     return result;
 132 }
 133
 134 time_t mktimegm(struct tm *tm)
 135 {
 136     time_t t;
 137     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 138     if (m < 3) {
 139         m += 12;
 140         y--;
 141     }
 142     t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
 143                  y / 400 - 719469);
 144     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 145     return t;
 146 }
 147
 148 /*
 149  * Make sure data goes on disk, but if possible do not bother to
 150  * write out the inode just for timestamp updates.
 151  *
 152  * Unfortunately even in 2009 many operating systems do not support
 153  * fdatasync and have to fall back to fsync.
 154  */
 155 int qemu_fdatasync(int fd)
 156 {
 157 #ifdef CONFIG_FDATASYNC
 158     return fdatasync(fd);
 159 #else
 160     return fsync(fd);
 161 #endif
 162 }
 163
 164 /* vector definitions */
 165 #ifdef __ALTIVEC__
 166 #include <altivec.h>
 167 /* The altivec.h header says we're allowed to undef these for
 168  * C++ compatibility.  Here we don't care about C++, but we
 169  * undef them anyway to avoid namespace pollution.
 170  */
 171 #undef vector
 172 #undef pixel
 173 #undef bool
 174 #define VECTYPE        __vector unsigned char
 175 #define SPLAT(p)       vec_splat(vec_ld(0, p), 0)
 176 #define ALL_EQ(v1, v2) vec_all_eq(v1, v2)
 177 #define VEC_OR(v1, v2) ((v1) | (v2))
 178 /* altivec.h may redefine the bool macro as vector type.
 179  * Reset it to POSIX semantics. */
 180 #define bool _Bool
 181 #elif defined __SSE2__
 182 #include <emmintrin.h>
 183 #define VECTYPE        __m128i
 184 #define SPLAT(p)       _mm_set1_epi8(*(p))
 185 #define ALL_EQ(v1, v2) (_mm_movemask_epi8(_mm_cmpeq_epi8(v1, v2)) == 0xFFFF)
 186 #define VEC_OR(v1, v2) (_mm_or_si128(v1, v2))
 187 #elif defined(__aarch64__)
 188 #include "arm_neon.h"
 189 #define VECTYPE        uint64x2_t
 190 #define ALL_EQ(v1, v2) \
 191         ((vgetq_lane_u64(v1, 0) == vgetq_lane_u64(v2, 0)) && \
 192          (vgetq_lane_u64(v1, 1) == vgetq_lane_u64(v2, 1)))
 193 #define VEC_OR(v1, v2) ((v1) | (v2))
 194 #else
 195 #define VECTYPE        unsigned long
 196 #define SPLAT(p)       (*(p) * (~0UL / 255))
 197 #define ALL_EQ(v1, v2) ((v1) == (v2))
 198 #define VEC_OR(v1, v2) ((v1) | (v2))
 199 #endif
 200
 201 #define BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR 8
 202
 203 static bool
 204 can_use_buffer_find_nonzero_offset_inner(const void *buf, size_t len)
 205 {
 206     return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
 207                    * sizeof(VECTYPE)) == 0
 208             && ((uintptr_t) buf) % sizeof(VECTYPE) == 0);
 209 }
 210
 211 /*
 212  * Searches for an area with non-zero content in a buffer
 213  *
 214  * Attention! The len must be a multiple of
 215  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 216  * and addr must be a multiple of sizeof(VECTYPE) due to
 217  * restriction of optimizations in this function.
 218  *
 219  * can_use_buffer_find_nonzero_offset_inner() can be used to
 220  * check these requirements.
 221  *
 222  * The return value is the offset of the non-zero area rounded
 223  * down to a multiple of sizeof(VECTYPE) for the first
 224  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR chunks and down to
 225  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 226  * afterwards.
 227  *
 228  * If the buffer is all zero the return value is equal to len.
 229  */
 230
 231 static size_t buffer_find_nonzero_offset_inner(const void *buf, size_t len)
 232 {
 233     const VECTYPE *p = buf;
 234     const VECTYPE zero = (VECTYPE){0};
 235     size_t i;
 236
 237     assert(can_use_buffer_find_nonzero_offset_inner(buf, len));
 238
 239     if (!len) {
 240         return 0;
 241     }
 242
 243     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 244         if (!ALL_EQ(p[i], zero)) {
 245             return i * sizeof(VECTYPE);
 246         }
 247     }
 248
 249     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 250          i < len / sizeof(VECTYPE);
 251          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 252         VECTYPE tmp0 = VEC_OR(p[i + 0], p[i + 1]);
 253         VECTYPE tmp1 = VEC_OR(p[i + 2], p[i + 3]);
 254         VECTYPE tmp2 = VEC_OR(p[i + 4], p[i + 5]);
 255         VECTYPE tmp3 = VEC_OR(p[i + 6], p[i + 7]);
 256         VECTYPE tmp01 = VEC_OR(tmp0, tmp1);
 257         VECTYPE tmp23 = VEC_OR(tmp2, tmp3);
 258         if (!ALL_EQ(VEC_OR(tmp01, tmp23), zero)) {
 259             break;
 260         }
 261     }
 262
 263     return i * sizeof(VECTYPE);
 264 }
 265
 266 #if defined CONFIG_AVX2_OPT
 267 #pragma GCC push_options
 268 #pragma GCC target("avx2")
 269 #include <cpuid.h>
 270 #include <immintrin.h>
 271
 272 #define AVX2_VECTYPE        __m256i
 273 #define AVX2_SPLAT(p)       _mm256_set1_epi8(*(p))
 274 #define AVX2_ALL_EQ(v1, v2) \
 275     (_mm256_movemask_epi8(_mm256_cmpeq_epi8(v1, v2)) == 0xFFFFFFFF)
 276 #define AVX2_VEC_OR(v1, v2) (_mm256_or_si256(v1, v2))
 277
 278 static bool
 279 can_use_buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
 280 {
 281     return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
 282                    * sizeof(AVX2_VECTYPE)) == 0
 283             && ((uintptr_t) buf) % sizeof(AVX2_VECTYPE) == 0);
 284 }
 285
 286 static size_t buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
 287 {
 288     const AVX2_VECTYPE *p = buf;
 289     const AVX2_VECTYPE zero = (AVX2_VECTYPE){0};
 290     size_t i;
 291
 292     assert(can_use_buffer_find_nonzero_offset_avx2(buf, len));
 293
 294     if (!len) {
 295         return 0;
 296     }
 297
 298     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 299         if (!AVX2_ALL_EQ(p[i], zero)) {
 300             return i * sizeof(AVX2_VECTYPE);
 301         }
 302     }
 303
 304     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 305          i < len / sizeof(AVX2_VECTYPE);
 306          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 307         AVX2_VECTYPE tmp0 = AVX2_VEC_OR(p[i + 0], p[i + 1]);
 308         AVX2_VECTYPE tmp1 = AVX2_VEC_OR(p[i + 2], p[i + 3]);
 309         AVX2_VECTYPE tmp2 = AVX2_VEC_OR(p[i + 4], p[i + 5]);
 310         AVX2_VECTYPE tmp3 = AVX2_VEC_OR(p[i + 6], p[i + 7]);
 311         AVX2_VECTYPE tmp01 = AVX2_VEC_OR(tmp0, tmp1);
 312         AVX2_VECTYPE tmp23 = AVX2_VEC_OR(tmp2, tmp3);
 313         if (!AVX2_ALL_EQ(AVX2_VEC_OR(tmp01, tmp23), zero)) {
 314             break;
 315         }
 316     }
 317
 318     return i * sizeof(AVX2_VECTYPE);
 319 }
 320
 321 static bool avx2_support(void)
 322 {
 323     int a, b, c, d;
 324
 325     if (__get_cpuid_max(0, NULL) < 7) {
 326         return false;
 327     }
 328
 329     __cpuid_count(7, 0, a, b, c, d);
 330
 331     return b & bit_AVX2;
 332 }
 333
 334 bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
 335          __attribute__ ((ifunc("can_use_buffer_find_nonzero_offset_ifunc")));
 336 size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
 337          __attribute__ ((ifunc("buffer_find_nonzero_offset_ifunc")));
 338
 339 static void *buffer_find_nonzero_offset_ifunc(void)
 340 {
 341     typeof(buffer_find_nonzero_offset) *func = (avx2_support()) ?
 342         buffer_find_nonzero_offset_avx2 : buffer_find_nonzero_offset_inner;
 343
 344     return func;
 345 }
 346
 347 static void *can_use_buffer_find_nonzero_offset_ifunc(void)
 348 {
 349     typeof(can_use_buffer_find_nonzero_offset) *func = (avx2_support()) ?
 350         can_use_buffer_find_nonzero_offset_avx2 :
 351         can_use_buffer_find_nonzero_offset_inner;
 352
 353     return func;
 354 }
 355 #pragma GCC pop_options
 356 #else
 357 bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
 358 {
 359     return can_use_buffer_find_nonzero_offset_inner(buf, len);
 360 }
 361
 362 size_t buffer_find_nonzero_offset(const void *buf, size_t len)
 363 {
 364     return buffer_find_nonzero_offset_inner(buf, len);
 365 }
 366 #endif
 367
 368 /*
 369  * Checks if a buffer is all zeroes
 370  *
 371  * Attention! The len must be a multiple of 4 * sizeof(long) due to
 372  * restriction of optimizations in this function.
 373  */
 374 bool buffer_is_zero(const void *buf, size_t len)
 375 {
 376     /*
 377      * Use long as the biggest available internal data type that fits into the
 378      * CPU register and unroll the loop to smooth out the effect of memory
 379      * latency.
 380      */
 381
 382     size_t i;
 383     long d0, d1, d2, d3;
 384     const long * const data = buf;
 385
 386     /* use vector optimized zero check if possible */
 387     if (can_use_buffer_find_nonzero_offset(buf, len)) {
 388         return buffer_find_nonzero_offset(buf, len) == len;
 389     }
 390
 391     assert(len % (4 * sizeof(long)) == 0);
 392     len /= sizeof(long);
 393
 394     for (i = 0; i < len; i += 4) {
 395         d0 = data[i + 0];
 396         d1 = data[i + 1];
 397         d2 = data[i + 2];
 398         d3 = data[i + 3];
 399
 400         if (d0 || d1 || d2 || d3) {
 401             return false;
 402         }
 403     }
 404
 405     return true;
 406 }
 407
 408 #ifndef _WIN32
 409 /* Sets a specific flag */
 410 int fcntl_setfl(int fd, int flag)
 411 {
 412     int flags;
 413
 414     flags = fcntl(fd, F_GETFL);
 415     if (flags == -1)
 416         return -errno;
 417
 418     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 419         return -errno;
 420
 421     return 0;
 422 }
 423 #endif
 424
 425 static int64_t suffix_mul(char suffix, int64_t unit)
 426 {
 427     switch (qemu_toupper(suffix)) {
 428     case QEMU_STRTOSZ_DEFSUFFIX_B:
 429         return 1;
 430     case QEMU_STRTOSZ_DEFSUFFIX_KB:
 431         return unit;
 432     case QEMU_STRTOSZ_DEFSUFFIX_MB:
 433         return unit * unit;
 434     case QEMU_STRTOSZ_DEFSUFFIX_GB:
 435         return unit * unit * unit;
 436     case QEMU_STRTOSZ_DEFSUFFIX_TB:
 437         return unit * unit * unit * unit;
 438     case QEMU_STRTOSZ_DEFSUFFIX_PB:
 439         return unit * unit * unit * unit * unit;
 440     case QEMU_STRTOSZ_DEFSUFFIX_EB:
 441         return unit * unit * unit * unit * unit * unit;
 442     }
 443     return -1;
 444 }
 445
 446 /*
 447  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 448  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 449  * in *end, if not NULL. Return -ERANGE on overflow, Return -EINVAL on
 450  * other error.
 451  */
 452 int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
 453                             const char default_suffix, int64_t unit)
 454 {
 455     int64_t retval = -EINVAL;
 456     char *endptr;
 457     unsigned char c;
 458     int mul_required = 0;
 459     double val, mul, integral, fraction;
 460
 461     errno = 0;
 462     val = strtod(nptr, &endptr);
 463     if (isnan(val) || endptr == nptr || errno != 0) {
 464         goto fail;
 465     }
 466     fraction = modf(val, &integral);
 467     if (fraction != 0) {
 468         mul_required = 1;
 469     }
 470     c = *endptr;
 471     mul = suffix_mul(c, unit);
 472     if (mul >= 0) {
 473         endptr++;
 474     } else {
 475         mul = suffix_mul(default_suffix, unit);
 476         assert(mul >= 0);
 477     }
 478     if (mul == 1 && mul_required) {
 479         goto fail;
 480     }
 481     if ((val * mul >= INT64_MAX) || val < 0) {
 482         retval = -ERANGE;
 483         goto fail;
 484     }
 485     retval = val * mul;
 486
 487 fail:
 488     if (end) {
 489         *end = endptr;
 490     }
 491
 492     return retval;
 493 }
 494
 495 int64_t qemu_strtosz_suffix(const char *nptr, char **end,
 496                             const char default_suffix)
 497 {
 498     return qemu_strtosz_suffix_unit(nptr, end, default_suffix, 1024);
 499 }
 500
 501 int64_t qemu_strtosz(const char *nptr, char **end)
 502 {
 503     return qemu_strtosz_suffix(nptr, end, QEMU_STRTOSZ_DEFSUFFIX_MB);
 504 }
 505
 506 /**
 507  * Helper function for qemu_strto*l() functions.
 508  */
 509 static int check_strtox_error(const char *p, char *endptr, const char **next,
 510                               int err)
 511 {
 512     /* If no conversion was performed, prefer BSD behavior over glibc
 513      * behavior.
 514      */
 515     if (err == 0 && endptr == p) {
 516         err = EINVAL;
 517     }
 518     if (!next && *endptr) {
 519         return -EINVAL;
 520     }
 521     if (next) {
 522         *next = endptr;
 523     }
 524     return -err;
 525 }
 526
 527 /**
 528  * QEMU wrappers for strtol(), strtoll(), strtoul(), strotull() C functions.
 529  *
 530  * Convert ASCII string @nptr to a long integer value
 531  * from the given @base. Parameters @nptr, @endptr, @base
 532  * follows same semantics as strtol() C function.
 533  *
 534  * Unlike from strtol() function, if @endptr is not NULL, this
 535  * function will return -EINVAL whenever it cannot fully convert
 536  * the string in @nptr with given @base to a long. This function returns
 537  * the result of the conversion only through the @result parameter.
 538  *
 539  * If NULL is passed in @endptr, then the whole string in @ntpr
 540  * is a number otherwise it returns -EINVAL.
 541  *
 542  * RETURN VALUE
 543  * Unlike from strtol() function, this wrapper returns either
 544  * -EINVAL or the errno set by strtol() function (e.g -ERANGE).
 545  * If the conversion overflows, -ERANGE is returned, and @result
 546  * is set to the max value of the desired type
 547  * (e.g. LONG_MAX, LLONG_MAX, ULONG_MAX, ULLONG_MAX). If the case
 548  * of underflow, -ERANGE is returned, and @result is set to the min
 549  * value of the desired type. For strtol(), strtoll(), @result is set to
 550  * LONG_MIN, LLONG_MIN, respectively, and for strtoul(), strtoull() it
 551  * is set to 0.
 552  */
 553 int qemu_strtol(const char *nptr, const char **endptr, int base,
 554                 long *result)
 555 {
 556     char *p;
 557     int err = 0;
 558     if (!nptr) {
 559         if (endptr) {
 560             *endptr = nptr;
 561         }
 562         err = -EINVAL;
 563     } else {
 564         errno = 0;
 565         *result = strtol(nptr, &p, base);
 566         err = check_strtox_error(nptr, p, endptr, errno);
 567     }
 568     return err;
 569 }
 570
 571 /**
 572  * Converts ASCII string to an unsigned long integer.
 573  *
 574  * If string contains a negative number, value will be converted to
 575  * the unsigned representation of the signed value, unless the original
 576  * (nonnegated) value would overflow, in this case, it will set @result
 577  * to ULONG_MAX, and return ERANGE.
 578  *
 579  * The same behavior holds, for qemu_strtoull() but sets @result to
 580  * ULLONG_MAX instead of ULONG_MAX.
 581  *
 582  * See qemu_strtol() documentation for more info.
 583  */
 584 int qemu_strtoul(const char *nptr, const char **endptr, int base,
 585                  unsigned long *result)
 586 {
 587     char *p;
 588     int err = 0;
 589     if (!nptr) {
 590         if (endptr) {
 591             *endptr = nptr;
 592         }
 593         err = -EINVAL;
 594     } else {
 595         errno = 0;
 596         *result = strtoul(nptr, &p, base);
 597         /* Windows returns 1 for negative out-of-range values.  */
 598         if (errno == ERANGE) {
 599             *result = -1;
 600         }
 601         err = check_strtox_error(nptr, p, endptr, errno);
 602     }
 603     return err;
 604 }
 605
 606 /**
 607  * Converts ASCII string to a long long integer.
 608  *
 609  * See qemu_strtol() documentation for more info.
 610  */
 611 int qemu_strtoll(const char *nptr, const char **endptr, int base,
 612                  int64_t *result)
 613 {
 614     char *p;
 615     int err = 0;
 616     if (!nptr) {
 617         if (endptr) {
 618             *endptr = nptr;
 619         }
 620         err = -EINVAL;
 621     } else {
 622         errno = 0;
 623         *result = strtoll(nptr, &p, base);
 624         err = check_strtox_error(nptr, p, endptr, errno);
 625     }
 626     return err;
 627 }
 628
 629 /**
 630  * Converts ASCII string to an unsigned long long integer.
 631  *
 632  * See qemu_strtol() documentation for more info.
 633  */
 634 int qemu_strtoull(const char *nptr, const char **endptr, int base,
 635                   uint64_t *result)
 636 {
 637     char *p;
 638     int err = 0;
 639     if (!nptr) {
 640         if (endptr) {
 641             *endptr = nptr;
 642         }
 643         err = -EINVAL;
 644     } else {
 645         errno = 0;
 646         *result = strtoull(nptr, &p, base);
 647         /* Windows returns 1 for negative out-of-range values.  */
 648         if (errno == ERANGE) {
 649             *result = -1;
 650         }
 651         err = check_strtox_error(nptr, p, endptr, errno);
 652     }
 653     return err;
 654 }
 655
 656 /**
 657  * parse_uint:
 658  *
 659  * @s: String to parse
 660  * @value: Destination for parsed integer value
 661  * @endptr: Destination for pointer to first character not consumed
 662  * @base: integer base, between 2 and 36 inclusive, or 0
 663  *
 664  * Parse unsigned integer
 665  *
 666  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 667  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 668  *
 669  * If @s is null, or @base is invalid, or @s doesn't start with an
 670  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 671  * return -EINVAL.
 672  *
 673  * Set *@endptr to point right beyond the parsed integer (even if the integer
 674  * overflows or is negative, all digits will be parsed and *@endptr will
 675  * point right beyond them).
 676  *
 677  * If the integer is negative, set *@value to 0, and return -ERANGE.
 678  *
 679  * If the integer overflows unsigned long long, set *@value to
 680  * ULLONG_MAX, and return -ERANGE.
 681  *
 682  * Else, set *@value to the parsed integer, and return 0.
 683  */
 684 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 685                int base)
 686 {
 687     int r = 0;
 688     char *endp = (char *)s;
 689     unsigned long long val = 0;
 690
 691     if (!s) {
 692         r = -EINVAL;
 693         goto out;
 694     }
 695
 696     errno = 0;
 697     val = strtoull(s, &endp, base);
 698     if (errno) {
 699         r = -errno;
 700         goto out;
 701     }
 702
 703     if (endp == s) {
 704         r = -EINVAL;
 705         goto out;
 706     }
 707
 708     /* make sure we reject negative numbers: */
 709     while (isspace((unsigned char)*s)) {
 710         s++;
 711     }
 712     if (*s == '-') {
 713         val = 0;
 714         r = -ERANGE;
 715         goto out;
 716     }
 717
 718 out:
 719     *value = val;
 720     *endptr = endp;
 721     return r;
 722 }
 723
 724 /**
 725  * parse_uint_full:
 726  *
 727  * @s: String to parse
 728  * @value: Destination for parsed integer value
 729  * @base: integer base, between 2 and 36 inclusive, or 0
 730  *
 731  * Parse unsigned integer from entire string
 732  *
 733  * Have the same behavior of parse_uint(), but with an additional check
 734  * for additional data after the parsed number. If extra characters are present
 735  * after the parsed number, the function will return -EINVAL, and *@v will
 736  * be set to 0.
 737  */
 738 int parse_uint_full(const char *s, unsigned long long *value, int base)
 739 {
 740     char *endp;
 741     int r;
 742
 743     r = parse_uint(s, value, &endp, base);
 744     if (r < 0) {
 745         return r;
 746     }
 747     if (*endp) {
 748         *value = 0;
 749         return -EINVAL;
 750     }
 751
 752     return 0;
 753 }
 754
 755 int qemu_parse_fd(const char *param)
 756 {
 757     long fd;
 758     char *endptr;
 759
 760     errno = 0;
 761     fd = strtol(param, &endptr, 10);
 762     if (param == endptr /* no conversion performed */                    ||
 763         errno != 0      /* not representable as long; possibly others */ ||
 764         *endptr != '\0' /* final string not empty */                     ||
 765         fd < 0          /* invalid as file descriptor */                 ||
 766         fd > INT_MAX    /* not representable as int */) {
 767         return -1;
 768     }
 769     return fd;
 770 }
 771
 772 /*
 773  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 774  * Input is limited to 14-bit numbers
 775  */
 776 int uleb128_encode_small(uint8_t *out, uint32_t n)
 777 {
 778     g_assert(n <= 0x3fff);
 779     if (n < 0x80) {
 780         *out++ = n;
 781         return 1;
 782     } else {
 783         *out++ = (n & 0x7f) | 0x80;
 784         *out++ = n >> 7;
 785         return 2;
 786     }
 787 }
 788
 789 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 790 {
 791     if (!(*in & 0x80)) {
 792         *n = *in++;
 793         return 1;
 794     } else {
 795         *n = *in++ & 0x7f;
 796         /* we exceed 14 bit number */
 797         if (*in & 0x80) {
 798             return -1;
 799         }
 800         *n |= *in++ << 7;
 801         return 2;
 802     }
 803 }
 804
 805 /*
 806  * helper to parse debug environment variables
 807  */
 808 int parse_debug_env(const char *name, int max, int initial)
 809 {
 810     char *debug_env = getenv(name);
 811     char *inv = NULL;
 812     long debug;
 813
 814     if (!debug_env) {
 815         return initial;
 816     }
 817     errno = 0;
 818     debug = strtol(debug_env, &inv, 10);
 819     if (inv == debug_env) {
 820         return initial;
 821     }
 822     if (debug < 0 || debug > max || errno != 0) {
 823         fprintf(stderr, "warning: %s not in [0, %d]", name, max);
 824         return initial;
 825     }
 826     return debug;
 827 }
 828
 829 /*
 830  * Helper to print ethernet mac address
 831  */
 832 const char *qemu_ether_ntoa(const MACAddr *mac)
 833 {
 834     static char ret[18];
 835
 836     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 837              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 838
 839     return ret;
 840 }