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 #else
 188 #define VECTYPE        unsigned long
 189 #define SPLAT(p)       (*(p) * (~0UL / 255))
 190 #define ALL_EQ(v1, v2) ((v1) == (v2))
 191 #define VEC_OR(v1, v2) ((v1) | (v2))
 192 #endif
 193
 194 #define BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR 8
 195
 196 static bool
 197 can_use_buffer_find_nonzero_offset_inner(const void *buf, size_t len)
 198 {
 199     return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
 200                    * sizeof(VECTYPE)) == 0
 201             && ((uintptr_t) buf) % sizeof(VECTYPE) == 0);
 202 }
 203
 204 /*
 205  * Searches for an area with non-zero content in a buffer
 206  *
 207  * Attention! The len must be a multiple of
 208  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 209  * and addr must be a multiple of sizeof(VECTYPE) due to
 210  * restriction of optimizations in this function.
 211  *
 212  * can_use_buffer_find_nonzero_offset_inner() can be used to
 213  * check these requirements.
 214  *
 215  * The return value is the offset of the non-zero area rounded
 216  * down to a multiple of sizeof(VECTYPE) for the first
 217  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR chunks and down to
 218  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 219  * afterwards.
 220  *
 221  * If the buffer is all zero the return value is equal to len.
 222  */
 223
 224 static size_t buffer_find_nonzero_offset_inner(const void *buf, size_t len)
 225 {
 226     const VECTYPE *p = buf;
 227     const VECTYPE zero = (VECTYPE){0};
 228     size_t i;
 229
 230     assert(can_use_buffer_find_nonzero_offset_inner(buf, len));
 231
 232     if (!len) {
 233         return 0;
 234     }
 235
 236     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 237         if (!ALL_EQ(p[i], zero)) {
 238             return i * sizeof(VECTYPE);
 239         }
 240     }
 241
 242     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 243          i < len / sizeof(VECTYPE);
 244          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 245         VECTYPE tmp0 = VEC_OR(p[i + 0], p[i + 1]);
 246         VECTYPE tmp1 = VEC_OR(p[i + 2], p[i + 3]);
 247         VECTYPE tmp2 = VEC_OR(p[i + 4], p[i + 5]);
 248         VECTYPE tmp3 = VEC_OR(p[i + 6], p[i + 7]);
 249         VECTYPE tmp01 = VEC_OR(tmp0, tmp1);
 250         VECTYPE tmp23 = VEC_OR(tmp2, tmp3);
 251         if (!ALL_EQ(VEC_OR(tmp01, tmp23), zero)) {
 252             break;
 253         }
 254     }
 255
 256     return i * sizeof(VECTYPE);
 257 }
 258
 259 /*
 260  * GCC before version 4.9 has a bug which will cause the target
 261  * attribute work incorrectly and failed to compile in some case,
 262  * restrict the gcc version to 4.9+ to prevent the failure.
 263  */
 264
 265 #if defined CONFIG_AVX2_OPT && QEMU_GNUC_PREREQ(4, 9)
 266 #pragma GCC push_options
 267 #pragma GCC target("avx2")
 268 #include <cpuid.h>
 269 #include <immintrin.h>
 270
 271 #define AVX2_VECTYPE        __m256i
 272 #define AVX2_SPLAT(p)       _mm256_set1_epi8(*(p))
 273 #define AVX2_ALL_EQ(v1, v2) \
 274     (_mm256_movemask_epi8(_mm256_cmpeq_epi8(v1, v2)) == 0xFFFFFFFF)
 275 #define AVX2_VEC_OR(v1, v2) (_mm256_or_si256(v1, v2))
 276
 277 static bool
 278 can_use_buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
 279 {
 280     return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
 281                    * sizeof(AVX2_VECTYPE)) == 0
 282             && ((uintptr_t) buf) % sizeof(AVX2_VECTYPE) == 0);
 283 }
 284
 285 static size_t buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
 286 {
 287     const AVX2_VECTYPE *p = buf;
 288     const AVX2_VECTYPE zero = (AVX2_VECTYPE){0};
 289     size_t i;
 290
 291     assert(can_use_buffer_find_nonzero_offset_avx2(buf, len));
 292
 293     if (!len) {
 294         return 0;
 295     }
 296
 297     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 298         if (!AVX2_ALL_EQ(p[i], zero)) {
 299             return i * sizeof(AVX2_VECTYPE);
 300         }
 301     }
 302
 303     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 304          i < len / sizeof(AVX2_VECTYPE);
 305          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 306         AVX2_VECTYPE tmp0 = AVX2_VEC_OR(p[i + 0], p[i + 1]);
 307         AVX2_VECTYPE tmp1 = AVX2_VEC_OR(p[i + 2], p[i + 3]);
 308         AVX2_VECTYPE tmp2 = AVX2_VEC_OR(p[i + 4], p[i + 5]);
 309         AVX2_VECTYPE tmp3 = AVX2_VEC_OR(p[i + 6], p[i + 7]);
 310         AVX2_VECTYPE tmp01 = AVX2_VEC_OR(tmp0, tmp1);
 311         AVX2_VECTYPE tmp23 = AVX2_VEC_OR(tmp2, tmp3);
 312         if (!AVX2_ALL_EQ(AVX2_VEC_OR(tmp01, tmp23), zero)) {
 313             break;
 314         }
 315     }
 316
 317     return i * sizeof(AVX2_VECTYPE);
 318 }
 319
 320 static bool avx2_support(void)
 321 {
 322     int a, b, c, d;
 323
 324     if (__get_cpuid_max(0, NULL) < 7) {
 325         return false;
 326     }
 327
 328     __cpuid_count(7, 0, a, b, c, d);
 329
 330     return b & bit_AVX2;
 331 }
 332
 333 bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len) \
 334          __attribute__ ((ifunc("can_use_buffer_find_nonzero_offset_ifunc")));
 335 size_t buffer_find_nonzero_offset(const void *buf, size_t len) \
 336          __attribute__ ((ifunc("buffer_find_nonzero_offset_ifunc")));
 337
 338 static void *buffer_find_nonzero_offset_ifunc(void)
 339 {
 340     typeof(buffer_find_nonzero_offset) *func = (avx2_support()) ?
 341         buffer_find_nonzero_offset_avx2 : buffer_find_nonzero_offset_inner;
 342
 343     return func;
 344 }
 345
 346 static void *can_use_buffer_find_nonzero_offset_ifunc(void)
 347 {
 348     typeof(can_use_buffer_find_nonzero_offset) *func = (avx2_support()) ?
 349         can_use_buffer_find_nonzero_offset_avx2 :
 350         can_use_buffer_find_nonzero_offset_inner;
 351
 352     return func;
 353 }
 354 #pragma GCC pop_options
 355 #else
 356 bool can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
 357 {
 358     return can_use_buffer_find_nonzero_offset_inner(buf, len);
 359 }
 360
 361 size_t buffer_find_nonzero_offset(const void *buf, size_t len)
 362 {
 363     return buffer_find_nonzero_offset_inner(buf, len);
 364 }
 365 #endif
 366
 367 /*
 368  * Checks if a buffer is all zeroes
 369  *
 370  * Attention! The len must be a multiple of 4 * sizeof(long) due to
 371  * restriction of optimizations in this function.
 372  */
 373 bool buffer_is_zero(const void *buf, size_t len)
 374 {
 375     /*
 376      * Use long as the biggest available internal data type that fits into the
 377      * CPU register and unroll the loop to smooth out the effect of memory
 378      * latency.
 379      */
 380
 381     size_t i;
 382     long d0, d1, d2, d3;
 383     const long * const data = buf;
 384
 385     /* use vector optimized zero check if possible */
 386     if (can_use_buffer_find_nonzero_offset(buf, len)) {
 387         return buffer_find_nonzero_offset(buf, len) == len;
 388     }
 389
 390     assert(len % (4 * sizeof(long)) == 0);
 391     len /= sizeof(long);
 392
 393     for (i = 0; i < len; i += 4) {
 394         d0 = data[i + 0];
 395         d1 = data[i + 1];
 396         d2 = data[i + 2];
 397         d3 = data[i + 3];
 398
 399         if (d0 || d1 || d2 || d3) {
 400             return false;
 401         }
 402     }
 403
 404     return true;
 405 }
 406
 407 #ifndef _WIN32
 408 /* Sets a specific flag */
 409 int fcntl_setfl(int fd, int flag)
 410 {
 411     int flags;
 412
 413     flags = fcntl(fd, F_GETFL);
 414     if (flags == -1)
 415         return -errno;
 416
 417     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 418         return -errno;
 419
 420     return 0;
 421 }
 422 #endif
 423
 424 static int64_t suffix_mul(char suffix, int64_t unit)
 425 {
 426     switch (qemu_toupper(suffix)) {
 427     case QEMU_STRTOSZ_DEFSUFFIX_B:
 428         return 1;
 429     case QEMU_STRTOSZ_DEFSUFFIX_KB:
 430         return unit;
 431     case QEMU_STRTOSZ_DEFSUFFIX_MB:
 432         return unit * unit;
 433     case QEMU_STRTOSZ_DEFSUFFIX_GB:
 434         return unit * unit * unit;
 435     case QEMU_STRTOSZ_DEFSUFFIX_TB:
 436         return unit * unit * unit * unit;
 437     case QEMU_STRTOSZ_DEFSUFFIX_PB:
 438         return unit * unit * unit * unit * unit;
 439     case QEMU_STRTOSZ_DEFSUFFIX_EB:
 440         return unit * unit * unit * unit * unit * unit;
 441     }
 442     return -1;
 443 }
 444
 445 /*
 446  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 447  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 448  * in *end, if not NULL. Return -ERANGE on overflow, Return -EINVAL on
 449  * other error.
 450  */
 451 int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
 452                             const char default_suffix, int64_t unit)
 453 {
 454     int64_t retval = -EINVAL;
 455     char *endptr;
 456     unsigned char c;
 457     int mul_required = 0;
 458     double val, mul, integral, fraction;
 459
 460     errno = 0;
 461     val = strtod(nptr, &endptr);
 462     if (isnan(val) || endptr == nptr || errno != 0) {
 463         goto fail;
 464     }
 465     fraction = modf(val, &integral);
 466     if (fraction != 0) {
 467         mul_required = 1;
 468     }
 469     c = *endptr;
 470     mul = suffix_mul(c, unit);
 471     if (mul >= 0) {
 472         endptr++;
 473     } else {
 474         mul = suffix_mul(default_suffix, unit);
 475         assert(mul >= 0);
 476     }
 477     if (mul == 1 && mul_required) {
 478         goto fail;
 479     }
 480     if ((val * mul >= INT64_MAX) || val < 0) {
 481         retval = -ERANGE;
 482         goto fail;
 483     }
 484     retval = val * mul;
 485
 486 fail:
 487     if (end) {
 488         *end = endptr;
 489     }
 490
 491     return retval;
 492 }
 493
 494 int64_t qemu_strtosz_suffix(const char *nptr, char **end,
 495                             const char default_suffix)
 496 {
 497     return qemu_strtosz_suffix_unit(nptr, end, default_suffix, 1024);
 498 }
 499
 500 int64_t qemu_strtosz(const char *nptr, char **end)
 501 {
 502     return qemu_strtosz_suffix(nptr, end, QEMU_STRTOSZ_DEFSUFFIX_MB);
 503 }
 504
 505 /**
 506  * Helper function for qemu_strto*l() functions.
 507  */
 508 static int check_strtox_error(const char *p, char *endptr, const char **next,
 509                               int err)
 510 {
 511     /* If no conversion was performed, prefer BSD behavior over glibc
 512      * behavior.
 513      */
 514     if (err == 0 && endptr == p) {
 515         err = EINVAL;
 516     }
 517     if (!next && *endptr) {
 518         return -EINVAL;
 519     }
 520     if (next) {
 521         *next = endptr;
 522     }
 523     return -err;
 524 }
 525
 526 /**
 527  * QEMU wrappers for strtol(), strtoll(), strtoul(), strotull() C functions.
 528  *
 529  * Convert ASCII string @nptr to a long integer value
 530  * from the given @base. Parameters @nptr, @endptr, @base
 531  * follows same semantics as strtol() C function.
 532  *
 533  * Unlike from strtol() function, if @endptr is not NULL, this
 534  * function will return -EINVAL whenever it cannot fully convert
 535  * the string in @nptr with given @base to a long. This function returns
 536  * the result of the conversion only through the @result parameter.
 537  *
 538  * If NULL is passed in @endptr, then the whole string in @ntpr
 539  * is a number otherwise it returns -EINVAL.
 540  *
 541  * RETURN VALUE
 542  * Unlike from strtol() function, this wrapper returns either
 543  * -EINVAL or the errno set by strtol() function (e.g -ERANGE).
 544  * If the conversion overflows, -ERANGE is returned, and @result
 545  * is set to the max value of the desired type
 546  * (e.g. LONG_MAX, LLONG_MAX, ULONG_MAX, ULLONG_MAX). If the case
 547  * of underflow, -ERANGE is returned, and @result is set to the min
 548  * value of the desired type. For strtol(), strtoll(), @result is set to
 549  * LONG_MIN, LLONG_MIN, respectively, and for strtoul(), strtoull() it
 550  * is set to 0.
 551  */
 552 int qemu_strtol(const char *nptr, const char **endptr, int base,
 553                 long *result)
 554 {
 555     char *p;
 556     int err = 0;
 557     if (!nptr) {
 558         if (endptr) {
 559             *endptr = nptr;
 560         }
 561         err = -EINVAL;
 562     } else {
 563         errno = 0;
 564         *result = strtol(nptr, &p, base);
 565         err = check_strtox_error(nptr, p, endptr, errno);
 566     }
 567     return err;
 568 }
 569
 570 /**
 571  * Converts ASCII string to an unsigned long integer.
 572  *
 573  * If string contains a negative number, value will be converted to
 574  * the unsigned representation of the signed value, unless the original
 575  * (nonnegated) value would overflow, in this case, it will set @result
 576  * to ULONG_MAX, and return ERANGE.
 577  *
 578  * The same behavior holds, for qemu_strtoull() but sets @result to
 579  * ULLONG_MAX instead of ULONG_MAX.
 580  *
 581  * See qemu_strtol() documentation for more info.
 582  */
 583 int qemu_strtoul(const char *nptr, const char **endptr, int base,
 584                  unsigned long *result)
 585 {
 586     char *p;
 587     int err = 0;
 588     if (!nptr) {
 589         if (endptr) {
 590             *endptr = nptr;
 591         }
 592         err = -EINVAL;
 593     } else {
 594         errno = 0;
 595         *result = strtoul(nptr, &p, base);
 596         /* Windows returns 1 for negative out-of-range values.  */
 597         if (errno == ERANGE) {
 598             *result = -1;
 599         }
 600         err = check_strtox_error(nptr, p, endptr, errno);
 601     }
 602     return err;
 603 }
 604
 605 /**
 606  * Converts ASCII string to a long long integer.
 607  *
 608  * See qemu_strtol() documentation for more info.
 609  */
 610 int qemu_strtoll(const char *nptr, const char **endptr, int base,
 611                  int64_t *result)
 612 {
 613     char *p;
 614     int err = 0;
 615     if (!nptr) {
 616         if (endptr) {
 617             *endptr = nptr;
 618         }
 619         err = -EINVAL;
 620     } else {
 621         errno = 0;
 622         *result = strtoll(nptr, &p, base);
 623         err = check_strtox_error(nptr, p, endptr, errno);
 624     }
 625     return err;
 626 }
 627
 628 /**
 629  * Converts ASCII string to an unsigned long long integer.
 630  *
 631  * See qemu_strtol() documentation for more info.
 632  */
 633 int qemu_strtoull(const char *nptr, const char **endptr, int base,
 634                   uint64_t *result)
 635 {
 636     char *p;
 637     int err = 0;
 638     if (!nptr) {
 639         if (endptr) {
 640             *endptr = nptr;
 641         }
 642         err = -EINVAL;
 643     } else {
 644         errno = 0;
 645         *result = strtoull(nptr, &p, base);
 646         /* Windows returns 1 for negative out-of-range values.  */
 647         if (errno == ERANGE) {
 648             *result = -1;
 649         }
 650         err = check_strtox_error(nptr, p, endptr, errno);
 651     }
 652     return err;
 653 }
 654
 655 /**
 656  * parse_uint:
 657  *
 658  * @s: String to parse
 659  * @value: Destination for parsed integer value
 660  * @endptr: Destination for pointer to first character not consumed
 661  * @base: integer base, between 2 and 36 inclusive, or 0
 662  *
 663  * Parse unsigned integer
 664  *
 665  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 666  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 667  *
 668  * If @s is null, or @base is invalid, or @s doesn't start with an
 669  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 670  * return -EINVAL.
 671  *
 672  * Set *@endptr to point right beyond the parsed integer (even if the integer
 673  * overflows or is negative, all digits will be parsed and *@endptr will
 674  * point right beyond them).
 675  *
 676  * If the integer is negative, set *@value to 0, and return -ERANGE.
 677  *
 678  * If the integer overflows unsigned long long, set *@value to
 679  * ULLONG_MAX, and return -ERANGE.
 680  *
 681  * Else, set *@value to the parsed integer, and return 0.
 682  */
 683 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 684                int base)
 685 {
 686     int r = 0;
 687     char *endp = (char *)s;
 688     unsigned long long val = 0;
 689
 690     if (!s) {
 691         r = -EINVAL;
 692         goto out;
 693     }
 694
 695     errno = 0;
 696     val = strtoull(s, &endp, base);
 697     if (errno) {
 698         r = -errno;
 699         goto out;
 700     }
 701
 702     if (endp == s) {
 703         r = -EINVAL;
 704         goto out;
 705     }
 706
 707     /* make sure we reject negative numbers: */
 708     while (isspace((unsigned char)*s)) {
 709         s++;
 710     }
 711     if (*s == '-') {
 712         val = 0;
 713         r = -ERANGE;
 714         goto out;
 715     }
 716
 717 out:
 718     *value = val;
 719     *endptr = endp;
 720     return r;
 721 }
 722
 723 /**
 724  * parse_uint_full:
 725  *
 726  * @s: String to parse
 727  * @value: Destination for parsed integer value
 728  * @base: integer base, between 2 and 36 inclusive, or 0
 729  *
 730  * Parse unsigned integer from entire string
 731  *
 732  * Have the same behavior of parse_uint(), but with an additional check
 733  * for additional data after the parsed number. If extra characters are present
 734  * after the parsed number, the function will return -EINVAL, and *@v will
 735  * be set to 0.
 736  */
 737 int parse_uint_full(const char *s, unsigned long long *value, int base)
 738 {
 739     char *endp;
 740     int r;
 741
 742     r = parse_uint(s, value, &endp, base);
 743     if (r < 0) {
 744         return r;
 745     }
 746     if (*endp) {
 747         *value = 0;
 748         return -EINVAL;
 749     }
 750
 751     return 0;
 752 }
 753
 754 int qemu_parse_fd(const char *param)
 755 {
 756     long fd;
 757     char *endptr;
 758
 759     errno = 0;
 760     fd = strtol(param, &endptr, 10);
 761     if (param == endptr /* no conversion performed */                    ||
 762         errno != 0      /* not representable as long; possibly others */ ||
 763         *endptr != '\0' /* final string not empty */                     ||
 764         fd < 0          /* invalid as file descriptor */                 ||
 765         fd > INT_MAX    /* not representable as int */) {
 766         return -1;
 767     }
 768     return fd;
 769 }
 770
 771 /*
 772  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 773  * Input is limited to 14-bit numbers
 774  */
 775 int uleb128_encode_small(uint8_t *out, uint32_t n)
 776 {
 777     g_assert(n <= 0x3fff);
 778     if (n < 0x80) {
 779         *out++ = n;
 780         return 1;
 781     } else {
 782         *out++ = (n & 0x7f) | 0x80;
 783         *out++ = n >> 7;
 784         return 2;
 785     }
 786 }
 787
 788 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 789 {
 790     if (!(*in & 0x80)) {
 791         *n = *in++;
 792         return 1;
 793     } else {
 794         *n = *in++ & 0x7f;
 795         /* we exceed 14 bit number */
 796         if (*in & 0x80) {
 797             return -1;
 798         }
 799         *n |= *in++ << 7;
 800         return 2;
 801     }
 802 }
 803
 804 /*
 805  * helper to parse debug environment variables
 806  */
 807 int parse_debug_env(const char *name, int max, int initial)
 808 {
 809     char *debug_env = getenv(name);
 810     char *inv = NULL;
 811     long debug;
 812
 813     if (!debug_env) {
 814         return initial;
 815     }
 816     errno = 0;
 817     debug = strtol(debug_env, &inv, 10);
 818     if (inv == debug_env) {
 819         return initial;
 820     }
 821     if (debug < 0 || debug > max || errno != 0) {
 822         fprintf(stderr, "warning: %s not in [0, %d]", name, max);
 823         return initial;
 824     }
 825     return debug;
 826 }
 827
 828 /*
 829  * Helper to print ethernet mac address
 830  */
 831 const char *qemu_ether_ntoa(const MACAddr *mac)
 832 {
 833     static char ret[18];
 834
 835     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 836              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 837
 838     return ret;
 839 }