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-common.h"
  25 #include "qemu/host-utils.h"
  26 #include <math.h>
  27 #include <limits.h>
  28 #include <errno.h>
  29
  30 #include "qemu/sockets.h"
  31 #include "qemu/iov.h"
  32 #include "net/net.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 int qemu_fls(int i)
 149 {
 150     return 32 - clz32(i);
 151 }
 152
 153 /*
 154  * Make sure data goes on disk, but if possible do not bother to
 155  * write out the inode just for timestamp updates.
 156  *
 157  * Unfortunately even in 2009 many operating systems do not support
 158  * fdatasync and have to fall back to fsync.
 159  */
 160 int qemu_fdatasync(int fd)
 161 {
 162 #ifdef CONFIG_FDATASYNC
 163     return fdatasync(fd);
 164 #else
 165     return fsync(fd);
 166 #endif
 167 }
 168
 169 /*
 170  * Searches for an area with non-zero content in a buffer
 171  *
 172  * Attention! The len must be a multiple of
 173  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 174  * and addr must be a multiple of sizeof(VECTYPE) due to
 175  * restriction of optimizations in this function.
 176  *
 177  * can_use_buffer_find_nonzero_offset() can be used to check
 178  * these requirements.
 179  *
 180  * The return value is the offset of the non-zero area rounded
 181  * down to a multiple of sizeof(VECTYPE) for the first
 182  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR chunks and down to
 183  * BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR * sizeof(VECTYPE)
 184  * afterwards.
 185  *
 186  * If the buffer is all zero the return value is equal to len.
 187  */
 188
 189 size_t buffer_find_nonzero_offset(const void *buf, size_t len)
 190 {
 191     const VECTYPE *p = buf;
 192     const VECTYPE zero = (VECTYPE){0};
 193     size_t i;
 194
 195     assert(can_use_buffer_find_nonzero_offset(buf, len));
 196
 197     if (!len) {
 198         return 0;
 199     }
 200
 201     for (i = 0; i < BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR; i++) {
 202         if (!ALL_EQ(p[i], zero)) {
 203             return i * sizeof(VECTYPE);
 204         }
 205     }
 206
 207     for (i = BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR;
 208          i < len / sizeof(VECTYPE);
 209          i += BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR) {
 210         VECTYPE tmp0 = p[i + 0] | p[i + 1];
 211         VECTYPE tmp1 = p[i + 2] | p[i + 3];
 212         VECTYPE tmp2 = p[i + 4] | p[i + 5];
 213         VECTYPE tmp3 = p[i + 6] | p[i + 7];
 214         VECTYPE tmp01 = tmp0 | tmp1;
 215         VECTYPE tmp23 = tmp2 | tmp3;
 216         if (!ALL_EQ(tmp01 | tmp23, zero)) {
 217             break;
 218         }
 219     }
 220
 221     return i * sizeof(VECTYPE);
 222 }
 223
 224 /*
 225  * Checks if a buffer is all zeroes
 226  *
 227  * Attention! The len must be a multiple of 4 * sizeof(long) due to
 228  * restriction of optimizations in this function.
 229  */
 230 bool buffer_is_zero(const void *buf, size_t len)
 231 {
 232     /*
 233      * Use long as the biggest available internal data type that fits into the
 234      * CPU register and unroll the loop to smooth out the effect of memory
 235      * latency.
 236      */
 237
 238     size_t i;
 239     long d0, d1, d2, d3;
 240     const long * const data = buf;
 241
 242     /* use vector optimized zero check if possible */
 243     if (can_use_buffer_find_nonzero_offset(buf, len)) {
 244         return buffer_find_nonzero_offset(buf, len) == len;
 245     }
 246
 247     assert(len % (4 * sizeof(long)) == 0);
 248     len /= sizeof(long);
 249
 250     for (i = 0; i < len; i += 4) {
 251         d0 = data[i + 0];
 252         d1 = data[i + 1];
 253         d2 = data[i + 2];
 254         d3 = data[i + 3];
 255
 256         if (d0 || d1 || d2 || d3) {
 257             return false;
 258         }
 259     }
 260
 261     return true;
 262 }
 263
 264 #ifndef _WIN32
 265 /* Sets a specific flag */
 266 int fcntl_setfl(int fd, int flag)
 267 {
 268     int flags;
 269
 270     flags = fcntl(fd, F_GETFL);
 271     if (flags == -1)
 272         return -errno;
 273
 274     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 275         return -errno;
 276
 277     return 0;
 278 }
 279 #endif
 280
 281 static int64_t suffix_mul(char suffix, int64_t unit)
 282 {
 283     switch (qemu_toupper(suffix)) {
 284     case STRTOSZ_DEFSUFFIX_B:
 285         return 1;
 286     case STRTOSZ_DEFSUFFIX_KB:
 287         return unit;
 288     case STRTOSZ_DEFSUFFIX_MB:
 289         return unit * unit;
 290     case STRTOSZ_DEFSUFFIX_GB:
 291         return unit * unit * unit;
 292     case STRTOSZ_DEFSUFFIX_TB:
 293         return unit * unit * unit * unit;
 294     case STRTOSZ_DEFSUFFIX_PB:
 295         return unit * unit * unit * unit * unit;
 296     case STRTOSZ_DEFSUFFIX_EB:
 297         return unit * unit * unit * unit * unit * unit;
 298     }
 299     return -1;
 300 }
 301
 302 /*
 303  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 304  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 305  * in *end, if not NULL. Return -ERANGE on overflow, Return -EINVAL on
 306  * other error.
 307  */
 308 int64_t strtosz_suffix_unit(const char *nptr, char **end,
 309                             const char default_suffix, int64_t unit)
 310 {
 311     int64_t retval = -EINVAL;
 312     char *endptr;
 313     unsigned char c;
 314     int mul_required = 0;
 315     double val, mul, integral, fraction;
 316
 317     errno = 0;
 318     val = strtod(nptr, &endptr);
 319     if (isnan(val) || endptr == nptr || errno != 0) {
 320         goto fail;
 321     }
 322     fraction = modf(val, &integral);
 323     if (fraction != 0) {
 324         mul_required = 1;
 325     }
 326     c = *endptr;
 327     mul = suffix_mul(c, unit);
 328     if (mul >= 0) {
 329         endptr++;
 330     } else {
 331         mul = suffix_mul(default_suffix, unit);
 332         assert(mul >= 0);
 333     }
 334     if (mul == 1 && mul_required) {
 335         goto fail;
 336     }
 337     if ((val * mul >= INT64_MAX) || val < 0) {
 338         retval = -ERANGE;
 339         goto fail;
 340     }
 341     retval = val * mul;
 342
 343 fail:
 344     if (end) {
 345         *end = endptr;
 346     }
 347
 348     return retval;
 349 }
 350
 351 int64_t strtosz_suffix(const char *nptr, char **end, const char default_suffix)
 352 {
 353     return strtosz_suffix_unit(nptr, end, default_suffix, 1024);
 354 }
 355
 356 int64_t strtosz(const char *nptr, char **end)
 357 {
 358     return strtosz_suffix(nptr, end, STRTOSZ_DEFSUFFIX_MB);
 359 }
 360
 361 /**
 362  * parse_uint:
 363  *
 364  * @s: String to parse
 365  * @value: Destination for parsed integer value
 366  * @endptr: Destination for pointer to first character not consumed
 367  * @base: integer base, between 2 and 36 inclusive, or 0
 368  *
 369  * Parse unsigned integer
 370  *
 371  * Parsed syntax is like strtoull()'s: arbitrary whitespace, a single optional
 372  * '+' or '-', an optional "0x" if @base is 0 or 16, one or more digits.
 373  *
 374  * If @s is null, or @base is invalid, or @s doesn't start with an
 375  * integer in the syntax above, set *@value to 0, *@endptr to @s, and
 376  * return -EINVAL.
 377  *
 378  * Set *@endptr to point right beyond the parsed integer (even if the integer
 379  * overflows or is negative, all digits will be parsed and *@endptr will
 380  * point right beyond them).
 381  *
 382  * If the integer is negative, set *@value to 0, and return -ERANGE.
 383  *
 384  * If the integer overflows unsigned long long, set *@value to
 385  * ULLONG_MAX, and return -ERANGE.
 386  *
 387  * Else, set *@value to the parsed integer, and return 0.
 388  */
 389 int parse_uint(const char *s, unsigned long long *value, char **endptr,
 390                int base)
 391 {
 392     int r = 0;
 393     char *endp = (char *)s;
 394     unsigned long long val = 0;
 395
 396     if (!s) {
 397         r = -EINVAL;
 398         goto out;
 399     }
 400
 401     errno = 0;
 402     val = strtoull(s, &endp, base);
 403     if (errno) {
 404         r = -errno;
 405         goto out;
 406     }
 407
 408     if (endp == s) {
 409         r = -EINVAL;
 410         goto out;
 411     }
 412
 413     /* make sure we reject negative numbers: */
 414     while (isspace((unsigned char)*s)) {
 415         s++;
 416     }
 417     if (*s == '-') {
 418         val = 0;
 419         r = -ERANGE;
 420         goto out;
 421     }
 422
 423 out:
 424     *value = val;
 425     *endptr = endp;
 426     return r;
 427 }
 428
 429 /**
 430  * parse_uint_full:
 431  *
 432  * @s: String to parse
 433  * @value: Destination for parsed integer value
 434  * @base: integer base, between 2 and 36 inclusive, or 0
 435  *
 436  * Parse unsigned integer from entire string
 437  *
 438  * Have the same behavior of parse_uint(), but with an additional check
 439  * for additional data after the parsed number. If extra characters are present
 440  * after the parsed number, the function will return -EINVAL, and *@v will
 441  * be set to 0.
 442  */
 443 int parse_uint_full(const char *s, unsigned long long *value, int base)
 444 {
 445     char *endp;
 446     int r;
 447
 448     r = parse_uint(s, value, &endp, base);
 449     if (r < 0) {
 450         return r;
 451     }
 452     if (*endp) {
 453         *value = 0;
 454         return -EINVAL;
 455     }
 456
 457     return 0;
 458 }
 459
 460 int qemu_parse_fd(const char *param)
 461 {
 462     long fd;
 463     char *endptr;
 464
 465     errno = 0;
 466     fd = strtol(param, &endptr, 10);
 467     if (param == endptr /* no conversion performed */                    ||
 468         errno != 0      /* not representable as long; possibly others */ ||
 469         *endptr != '\0' /* final string not empty */                     ||
 470         fd < 0          /* invalid as file descriptor */                 ||
 471         fd > INT_MAX    /* not representable as int */) {
 472         return -1;
 473     }
 474     return fd;
 475 }
 476
 477 /* round down to the nearest power of 2*/
 478 int64_t pow2floor(int64_t value)
 479 {
 480     if (!is_power_of_2(value)) {
 481         value = 0x8000000000000000ULL >> clz64(value);
 482     }
 483     return value;
 484 }
 485
 486 /* round up to the nearest power of 2 (0 if overflow) */
 487 uint64_t pow2ceil(uint64_t value)
 488 {
 489     uint8_t nlz = clz64(value);
 490
 491     if (is_power_of_2(value)) {
 492         return value;
 493     }
 494     if (!nlz) {
 495         return 0;
 496     }
 497     return 1ULL << (64 - nlz);
 498 }
 499
 500 /*
 501  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 502  * Input is limited to 14-bit numbers
 503  */
 504 int uleb128_encode_small(uint8_t *out, uint32_t n)
 505 {
 506     g_assert(n <= 0x3fff);
 507     if (n < 0x80) {
 508         *out++ = n;
 509         return 1;
 510     } else {
 511         *out++ = (n & 0x7f) | 0x80;
 512         *out++ = n >> 7;
 513         return 2;
 514     }
 515 }
 516
 517 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 518 {
 519     if (!(*in & 0x80)) {
 520         *n = *in++;
 521         return 1;
 522     } else {
 523         *n = *in++ & 0x7f;
 524         /* we exceed 14 bit number */
 525         if (*in & 0x80) {
 526             return -1;
 527         }
 528         *n |= *in++ << 7;
 529         return 2;
 530     }
 531 }
 532
 533 /*
 534  * helper to parse debug environment variables
 535  */
 536 int parse_debug_env(const char *name, int max, int initial)
 537 {
 538     char *debug_env = getenv(name);
 539     char *inv = NULL;
 540     int debug;
 541
 542     if (!debug_env) {
 543         return initial;
 544     }
 545     debug = strtol(debug_env, &inv, 10);
 546     if (inv == debug_env) {
 547         return initial;
 548     }
 549     if (debug < 0 || debug > max) {
 550         fprintf(stderr, "warning: %s not in [0, %d]", name, max);
 551         return initial;
 552     }
 553     return debug;
 554 }
 555
 556 /*
 557  * Helper to print ethernet mac address
 558  */
 559 const char *qemu_ether_ntoa(const MACAddr *mac)
 560 {
 561     static char ret[18];
 562
 563     snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
 564              mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
 565
 566     return ret;
 567 }