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 "host-utils.h"
  26 #include <math.h>
  27
  28 #include "qemu_socket.h"
  29 #include "iov.h"
  30
  31 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
  32 {
  33     int len = qemu_strnlen(str, buf_size);
  34     memcpy(buf, str, len);
  35     memset(buf + len, pad, buf_size - len);
  36 }
  37
  38 void pstrcpy(char *buf, int buf_size, const char *str)
  39 {
  40     int c;
  41     char *q = buf;
  42
  43     if (buf_size <= 0)
  44         return;
  45
  46     for(;;) {
  47         c = *str++;
  48         if (c == 0 || q >= buf + buf_size - 1)
  49             break;
  50         *q++ = c;
  51     }
  52     *q = '\0';
  53 }
  54
  55 /* strcat and truncate. */
  56 char *pstrcat(char *buf, int buf_size, const char *s)
  57 {
  58     int len;
  59     len = strlen(buf);
  60     if (len < buf_size)
  61         pstrcpy(buf + len, buf_size - len, s);
  62     return buf;
  63 }
  64
  65 int strstart(const char *str, const char *val, const char **ptr)
  66 {
  67     const char *p, *q;
  68     p = str;
  69     q = val;
  70     while (*q != '\0') {
  71         if (*p != *q)
  72             return 0;
  73         p++;
  74         q++;
  75     }
  76     if (ptr)
  77         *ptr = p;
  78     return 1;
  79 }
  80
  81 int stristart(const char *str, const char *val, const char **ptr)
  82 {
  83     const char *p, *q;
  84     p = str;
  85     q = val;
  86     while (*q != '\0') {
  87         if (qemu_toupper(*p) != qemu_toupper(*q))
  88             return 0;
  89         p++;
  90         q++;
  91     }
  92     if (ptr)
  93         *ptr = p;
  94     return 1;
  95 }
  96
  97 /* XXX: use host strnlen if available ? */
  98 int qemu_strnlen(const char *s, int max_len)
  99 {
 100     int i;
 101
 102     for(i = 0; i < max_len; i++) {
 103         if (s[i] == '\0') {
 104             break;
 105         }
 106     }
 107     return i;
 108 }
 109
 110 time_t mktimegm(struct tm *tm)
 111 {
 112     time_t t;
 113     int y = tm->tm_year + 1900, m = tm->tm_mon + 1, d = tm->tm_mday;
 114     if (m < 3) {
 115         m += 12;
 116         y--;
 117     }
 118     t = 86400ULL * (d + (153 * m - 457) / 5 + 365 * y + y / 4 - y / 100 +
 119                  y / 400 - 719469);
 120     t += 3600 * tm->tm_hour + 60 * tm->tm_min + tm->tm_sec;
 121     return t;
 122 }
 123
 124 int qemu_fls(int i)
 125 {
 126     return 32 - clz32(i);
 127 }
 128
 129 /*
 130  * Make sure data goes on disk, but if possible do not bother to
 131  * write out the inode just for timestamp updates.
 132  *
 133  * Unfortunately even in 2009 many operating systems do not support
 134  * fdatasync and have to fall back to fsync.
 135  */
 136 int qemu_fdatasync(int fd)
 137 {
 138 #ifdef CONFIG_FDATASYNC
 139     return fdatasync(fd);
 140 #else
 141     return fsync(fd);
 142 #endif
 143 }
 144
 145 /*
 146  * Checks if a buffer is all zeroes
 147  *
 148  * Attention! The len must be a multiple of 4 * sizeof(long) due to
 149  * restriction of optimizations in this function.
 150  */
 151 bool buffer_is_zero(const void *buf, size_t len)
 152 {
 153     /*
 154      * Use long as the biggest available internal data type that fits into the
 155      * CPU register and unroll the loop to smooth out the effect of memory
 156      * latency.
 157      */
 158
 159     size_t i;
 160     long d0, d1, d2, d3;
 161     const long * const data = buf;
 162
 163     assert(len % (4 * sizeof(long)) == 0);
 164     len /= sizeof(long);
 165
 166     for (i = 0; i < len; i += 4) {
 167         d0 = data[i + 0];
 168         d1 = data[i + 1];
 169         d2 = data[i + 2];
 170         d3 = data[i + 3];
 171
 172         if (d0 || d1 || d2 || d3) {
 173             return false;
 174         }
 175     }
 176
 177     return true;
 178 }
 179
 180 #ifndef _WIN32
 181 /* Sets a specific flag */
 182 int fcntl_setfl(int fd, int flag)
 183 {
 184     int flags;
 185
 186     flags = fcntl(fd, F_GETFL);
 187     if (flags == -1)
 188         return -errno;
 189
 190     if (fcntl(fd, F_SETFL, flags | flag) == -1)
 191         return -errno;
 192
 193     return 0;
 194 }
 195 #endif
 196
 197 static int64_t suffix_mul(char suffix, int64_t unit)
 198 {
 199     switch (qemu_toupper(suffix)) {
 200     case STRTOSZ_DEFSUFFIX_B:
 201         return 1;
 202     case STRTOSZ_DEFSUFFIX_KB:
 203         return unit;
 204     case STRTOSZ_DEFSUFFIX_MB:
 205         return unit * unit;
 206     case STRTOSZ_DEFSUFFIX_GB:
 207         return unit * unit * unit;
 208     case STRTOSZ_DEFSUFFIX_TB:
 209         return unit * unit * unit * unit;
 210     }
 211     return -1;
 212 }
 213
 214 /*
 215  * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
 216  * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
 217  * in *end, if not NULL. Return -1 on error.
 218  */
 219 int64_t strtosz_suffix_unit(const char *nptr, char **end,
 220                             const char default_suffix, int64_t unit)
 221 {
 222     int64_t retval = -1;
 223     char *endptr;
 224     unsigned char c;
 225     int mul_required = 0;
 226     double val, mul, integral, fraction;
 227
 228     errno = 0;
 229     val = strtod(nptr, &endptr);
 230     if (isnan(val) || endptr == nptr || errno != 0) {
 231         goto fail;
 232     }
 233     fraction = modf(val, &integral);
 234     if (fraction != 0) {
 235         mul_required = 1;
 236     }
 237     c = *endptr;
 238     mul = suffix_mul(c, unit);
 239     if (mul >= 0) {
 240         endptr++;
 241     } else {
 242         mul = suffix_mul(default_suffix, unit);
 243         assert(mul >= 0);
 244     }
 245     if (mul == 1 && mul_required) {
 246         goto fail;
 247     }
 248     if ((val * mul >= INT64_MAX) || val < 0) {
 249         goto fail;
 250     }
 251     retval = val * mul;
 252
 253 fail:
 254     if (end) {
 255         *end = endptr;
 256     }
 257
 258     return retval;
 259 }
 260
 261 int64_t strtosz_suffix(const char *nptr, char **end, const char default_suffix)
 262 {
 263     return strtosz_suffix_unit(nptr, end, default_suffix, 1024);
 264 }
 265
 266 int64_t strtosz(const char *nptr, char **end)
 267 {
 268     return strtosz_suffix(nptr, end, STRTOSZ_DEFSUFFIX_MB);
 269 }
 270
 271 int qemu_parse_fd(const char *param)
 272 {
 273     int fd;
 274     char *endptr = NULL;
 275
 276     fd = strtol(param, &endptr, 10);
 277     if (*endptr || (fd == 0 && param == endptr)) {
 278         return -1;
 279     }
 280     return fd;
 281 }
 282
 283 /* round down to the nearest power of 2*/
 284 int64_t pow2floor(int64_t value)
 285 {
 286     if (!is_power_of_2(value)) {
 287         value = 0x8000000000000000ULL >> clz64(value);
 288     }
 289     return value;
 290 }
 291
 292 /*
 293  * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
 294  * Input is limited to 14-bit numbers
 295  */
 296 int uleb128_encode_small(uint8_t *out, uint32_t n)
 297 {
 298     g_assert(n <= 0x3fff);
 299     if (n < 0x80) {
 300         *out++ = n;
 301         return 1;
 302     } else {
 303         *out++ = (n & 0x7f) | 0x80;
 304         *out++ = n >> 7;
 305         return 2;
 306     }
 307 }
 308
 309 int uleb128_decode_small(const uint8_t *in, uint32_t *n)
 310 {
 311     if (!(*in & 0x80)) {
 312         *n = *in++;
 313         return 1;
 314     } else {
 315         *n = *in++ & 0x7f;
 316         /* we exceed 14 bit number */
 317         if (*in & 0x80) {
 318             return -1;
 319         }
 320         *n |= *in++ << 7;
 321         return 2;
 322     }
 323 }