libsanitizer/sanitizer_common/sanitizer_libc.cc

   1 //===-- sanitizer_libc.cc -------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries. See sanitizer_libc.h for details.
  10 //===----------------------------------------------------------------------===//
  11
  12 #include "sanitizer_allocator_internal.h"
  13 #include "sanitizer_common.h"
  14 #include "sanitizer_libc.h"
  15
  16 namespace __sanitizer {
  17
  18 s64 internal_atoll(const char *nptr) {
  19   return internal_simple_strtoll(nptr, nullptr, 10);
  20 }
  21
  22 void *internal_memchr(const void *s, int c, uptr n) {
  23   const char *t = (const char *)s;
  24   for (uptr i = 0; i < n; ++i, ++t)
  25     if (*t == c)
  26       return reinterpret_cast<void *>(const_cast<char *>(t));
  27   return nullptr;
  28 }
  29
  30 void *internal_memrchr(const void *s, int c, uptr n) {
  31   const char *t = (const char *)s;
  32   void *res = nullptr;
  33   for (uptr i = 0; i < n; ++i, ++t) {
  34     if (*t == c) res = reinterpret_cast<void *>(const_cast<char *>(t));
  35   }
  36   return res;
  37 }
  38
  39 int internal_memcmp(const void* s1, const void* s2, uptr n) {
  40   const char *t1 = (const char *)s1;
  41   const char *t2 = (const char *)s2;
  42   for (uptr i = 0; i < n; ++i, ++t1, ++t2)
  43     if (*t1 != *t2)
  44       return *t1 < *t2 ? -1 : 1;
  45   return 0;
  46 }
  47
  48 void *internal_memcpy(void *dest, const void *src, uptr n) {
  49   char *d = (char*)dest;
  50   const char *s = (const char *)src;
  51   for (uptr i = 0; i < n; ++i)
  52     d[i] = s[i];
  53   return dest;
  54 }
  55
  56 void *internal_memmove(void *dest, const void *src, uptr n) {
  57   char *d = (char*)dest;
  58   const char *s = (const char *)src;
  59   sptr i, signed_n = (sptr)n;
  60   CHECK_GE(signed_n, 0);
  61   if (d < s) {
  62     for (i = 0; i < signed_n; ++i)
  63       d[i] = s[i];
  64   } else {
  65     if (d > s && signed_n > 0)
  66       for (i = signed_n - 1; i >= 0 ; --i) {
  67         d[i] = s[i];
  68       }
  69   }
  70   return dest;
  71 }
  72
  73 void *internal_memset(void* s, int c, uptr n) {
  74   // Optimize for the most performance-critical case:
  75   if ((reinterpret_cast<uptr>(s) % 16) == 0 && (n % 16) == 0) {
  76     u64 *p = reinterpret_cast<u64*>(s);
  77     u64 *e = p + n / 8;
  78     u64 v = c;
  79     v |= v << 8;
  80     v |= v << 16;
  81     v |= v << 32;
  82     for (; p < e; p += 2)
  83       p[0] = p[1] = v;
  84     return s;
  85   }
  86   // The next line prevents Clang from making a call to memset() instead of the
  87   // loop below.
  88   // FIXME: building the runtime with -ffreestanding is a better idea. However
  89   // there currently are linktime problems due to PR12396.
  90   char volatile *t = (char*)s;
  91   for (uptr i = 0; i < n; ++i, ++t) {
  92     *t = c;
  93   }
  94   return s;
  95 }
  96
  97 uptr internal_strcspn(const char *s, const char *reject) {
  98   uptr i;
  99   for (i = 0; s[i]; i++) {
 100     if (internal_strchr(reject, s[i]))
 101       return i;
 102   }
 103   return i;
 104 }
 105
 106 char* internal_strdup(const char *s) {
 107   uptr len = internal_strlen(s);
 108   char *s2 = (char*)InternalAlloc(len + 1);
 109   internal_memcpy(s2, s, len);
 110   s2[len] = 0;
 111   return s2;
 112 }
 113
 114 int internal_strcmp(const char *s1, const char *s2) {
 115   while (true) {
 116     unsigned c1 = *s1;
 117     unsigned c2 = *s2;
 118     if (c1 != c2) return (c1 < c2) ? -1 : 1;
 119     if (c1 == 0) break;
 120     s1++;
 121     s2++;
 122   }
 123   return 0;
 124 }
 125
 126 int internal_strncmp(const char *s1, const char *s2, uptr n) {
 127   for (uptr i = 0; i < n; i++) {
 128     unsigned c1 = *s1;
 129     unsigned c2 = *s2;
 130     if (c1 != c2) return (c1 < c2) ? -1 : 1;
 131     if (c1 == 0) break;
 132     s1++;
 133     s2++;
 134   }
 135   return 0;
 136 }
 137
 138 char* internal_strchr(const char *s, int c) {
 139   while (true) {
 140     if (*s == (char)c)
 141       return const_cast<char *>(s);
 142     if (*s == 0)
 143       return nullptr;
 144     s++;
 145   }
 146 }
 147
 148 char *internal_strchrnul(const char *s, int c) {
 149   char *res = internal_strchr(s, c);
 150   if (!res)
 151     res = const_cast<char *>(s) + internal_strlen(s);
 152   return res;
 153 }
 154
 155 char *internal_strrchr(const char *s, int c) {
 156   const char *res = nullptr;
 157   for (uptr i = 0; s[i]; i++) {
 158     if (s[i] == c) res = s + i;
 159   }
 160   return const_cast<char *>(res);
 161 }
 162
 163 uptr internal_strlen(const char *s) {
 164   uptr i = 0;
 165   while (s[i]) i++;
 166   return i;
 167 }
 168
 169 uptr internal_strlcat(char *dst, const char *src, uptr maxlen) {
 170   const uptr srclen = internal_strlen(src);
 171   const uptr dstlen = internal_strnlen(dst, maxlen);
 172   if (dstlen == maxlen) return maxlen + srclen;
 173   if (srclen < maxlen - dstlen) {
 174     internal_memmove(dst + dstlen, src, srclen + 1);
 175   } else {
 176     internal_memmove(dst + dstlen, src, maxlen - dstlen - 1);
 177     dst[maxlen - 1] = '\0';
 178   }
 179   return dstlen + srclen;
 180 }
 181
 182 char *internal_strncat(char *dst, const char *src, uptr n) {
 183   uptr len = internal_strlen(dst);
 184   uptr i;
 185   for (i = 0; i < n && src[i]; i++)
 186     dst[len + i] = src[i];
 187   dst[len + i] = 0;
 188   return dst;
 189 }
 190
 191 uptr internal_strlcpy(char *dst, const char *src, uptr maxlen) {
 192   const uptr srclen = internal_strlen(src);
 193   if (srclen < maxlen) {
 194     internal_memmove(dst, src, srclen + 1);
 195   } else if (maxlen != 0) {
 196     internal_memmove(dst, src, maxlen - 1);
 197     dst[maxlen - 1] = '\0';
 198   }
 199   return srclen;
 200 }
 201
 202 char *internal_strncpy(char *dst, const char *src, uptr n) {
 203   uptr i;
 204   for (i = 0; i < n && src[i]; i++)
 205     dst[i] = src[i];
 206   internal_memset(dst + i, '\0', n - i);
 207   return dst;
 208 }
 209
 210 uptr internal_strnlen(const char *s, uptr maxlen) {
 211   uptr i = 0;
 212   while (i < maxlen && s[i]) i++;
 213   return i;
 214 }
 215
 216 char *internal_strstr(const char *haystack, const char *needle) {
 217   // This is O(N^2), but we are not using it in hot places.
 218   uptr len1 = internal_strlen(haystack);
 219   uptr len2 = internal_strlen(needle);
 220   if (len1 < len2) return nullptr;
 221   for (uptr pos = 0; pos <= len1 - len2; pos++) {
 222     if (internal_memcmp(haystack + pos, needle, len2) == 0)
 223       return const_cast<char *>(haystack) + pos;
 224   }
 225   return nullptr;
 226 }
 227
 228 s64 internal_simple_strtoll(const char *nptr, const char **endptr, int base) {
 229   CHECK_EQ(base, 10);
 230   while (IsSpace(*nptr)) nptr++;
 231   int sgn = 1;
 232   u64 res = 0;
 233   bool have_digits = false;
 234   char *old_nptr = const_cast<char *>(nptr);
 235   if (*nptr == '+') {
 236     sgn = 1;
 237     nptr++;
 238   } else if (*nptr == '-') {
 239     sgn = -1;
 240     nptr++;
 241   }
 242   while (IsDigit(*nptr)) {
 243     res = (res <= UINT64_MAX / 10) ? res * 10 : UINT64_MAX;
 244     int digit = ((*nptr) - '0');
 245     res = (res <= UINT64_MAX - digit) ? res + digit : UINT64_MAX;
 246     have_digits = true;
 247     nptr++;
 248   }
 249   if (endptr) {
 250     *endptr = (have_digits) ? const_cast<char *>(nptr) : old_nptr;
 251   }
 252   if (sgn > 0) {
 253     return (s64)(Min((u64)INT64_MAX, res));
 254   } else {
 255     return (res > INT64_MAX) ? INT64_MIN : ((s64)res * -1);
 256   }
 257 }
 258
 259 bool mem_is_zero(const char *beg, uptr size) {
 260   CHECK_LE(size, 1ULL << FIRST_32_SECOND_64(30, 40));  // Sanity check.
 261   const char *end = beg + size;
 262   uptr *aligned_beg = (uptr *)RoundUpTo((uptr)beg, sizeof(uptr));
 263   uptr *aligned_end = (uptr *)RoundDownTo((uptr)end, sizeof(uptr));
 264   uptr all = 0;
 265   // Prologue.
 266   for (const char *mem = beg; mem < (char*)aligned_beg && mem < end; mem++)
 267     all |= *mem;
 268   // Aligned loop.
 269   for (; aligned_beg < aligned_end; aligned_beg++)
 270     all |= *aligned_beg;
 271   // Epilogue.
 272   if ((char*)aligned_end >= beg)
 273     for (const char *mem = (char*)aligned_end; mem < end; mem++)
 274       all |= *mem;
 275   return all == 0;
 276 }
 277
 278 } // namespace __sanitizer