libsanitizer/sanitizer_common/sanitizer_libc.cpp

   1 //===-- sanitizer_libc.cpp ------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is shared between AddressSanitizer and ThreadSanitizer
  10 // run-time libraries. See sanitizer_libc.h for details.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_allocator_internal.h"
  14 #include "sanitizer_common.h"
  15 #include "sanitizer_libc.h"
  16
  17 namespace __sanitizer {
  18
  19 s64 internal_atoll(const char *nptr) {
  20   return internal_simple_strtoll(nptr, nullptr, 10);
  21 }
  22
  23 void *internal_memchr(const void *s, int c, uptr n) {
  24   const char *t = (const char *)s;
  25   for (uptr i = 0; i < n; ++i, ++t)
  26     if (*t == c)
  27       return reinterpret_cast<void *>(const_cast<char *>(t));
  28   return nullptr;
  29 }
  30
  31 void *internal_memrchr(const void *s, int c, uptr n) {
  32   const char *t = (const char *)s;
  33   void *res = nullptr;
  34   for (uptr i = 0; i < n; ++i, ++t) {
  35     if (*t == c) res = reinterpret_cast<void *>(const_cast<char *>(t));
  36   }
  37   return res;
  38 }
  39
  40 int internal_memcmp(const void* s1, const void* s2, uptr n) {
  41   const char *t1 = (const char *)s1;
  42   const char *t2 = (const char *)s2;
  43   for (uptr i = 0; i < n; ++i, ++t1, ++t2)
  44     if (*t1 != *t2)
  45       return *t1 < *t2 ? -1 : 1;
  46   return 0;
  47 }
  48
  49 void *internal_memcpy(void *dest, const void *src, uptr n) {
  50   char *d = (char*)dest;
  51   const char *s = (const char *)src;
  52   for (uptr i = 0; i < n; ++i)
  53     d[i] = s[i];
  54   return dest;
  55 }
  56
  57 void *internal_memmove(void *dest, const void *src, uptr n) {
  58   char *d = (char*)dest;
  59   const char *s = (const char *)src;
  60   sptr i, signed_n = (sptr)n;
  61   CHECK_GE(signed_n, 0);
  62   if (d < s) {
  63     for (i = 0; i < signed_n; ++i)
  64       d[i] = s[i];
  65   } else {
  66     if (d > s && signed_n > 0) {
  67       for (i = signed_n - 1; i >= 0; --i) {
  68         d[i] = s[i];
  69       }
  70     }
  71   }
  72   return dest;
  73 }
  74
  75 void *internal_memset(void* s, int c, uptr n) {
  76   // Optimize for the most performance-critical case:
  77   if ((reinterpret_cast<uptr>(s) % 16) == 0 && (n % 16) == 0) {
  78     u64 *p = reinterpret_cast<u64*>(s);
  79     u64 *e = p + n / 8;
  80     u64 v = c;
  81     v |= v << 8;
  82     v |= v << 16;
  83     v |= v << 32;
  84     for (; p < e; p += 2)
  85       p[0] = p[1] = v;
  86     return s;
  87   }
  88   // The next line prevents Clang from making a call to memset() instead of the
  89   // loop below.
  90   // FIXME: building the runtime with -ffreestanding is a better idea. However
  91   // there currently are linktime problems due to PR12396.
  92   char volatile *t = (char*)s;
  93   for (uptr i = 0; i < n; ++i, ++t) {
  94     *t = c;
  95   }
  96   return s;
  97 }
  98
  99 uptr internal_strcspn(const char *s, const char *reject) {
 100   uptr i;
 101   for (i = 0; s[i]; i++) {
 102     if (internal_strchr(reject, s[i]))
 103       return i;
 104   }
 105   return i;
 106 }
 107
 108 char* internal_strdup(const char *s) {
 109   uptr len = internal_strlen(s);
 110   char *s2 = (char*)InternalAlloc(len + 1);
 111   internal_memcpy(s2, s, len);
 112   s2[len] = 0;
 113   return s2;
 114 }
 115
 116 int internal_strcmp(const char *s1, const char *s2) {
 117   while (true) {
 118     unsigned c1 = *s1;
 119     unsigned c2 = *s2;
 120     if (c1 != c2) return (c1 < c2) ? -1 : 1;
 121     if (c1 == 0) break;
 122     s1++;
 123     s2++;
 124   }
 125   return 0;
 126 }
 127
 128 int internal_strncmp(const char *s1, const char *s2, uptr n) {
 129   for (uptr i = 0; i < n; i++) {
 130     unsigned c1 = *s1;
 131     unsigned c2 = *s2;
 132     if (c1 != c2) return (c1 < c2) ? -1 : 1;
 133     if (c1 == 0) break;
 134     s1++;
 135     s2++;
 136   }
 137   return 0;
 138 }
 139
 140 char* internal_strchr(const char *s, int c) {
 141   while (true) {
 142     if (*s == (char)c)
 143       return const_cast<char *>(s);
 144     if (*s == 0)
 145       return nullptr;
 146     s++;
 147   }
 148 }
 149
 150 char *internal_strchrnul(const char *s, int c) {
 151   char *res = internal_strchr(s, c);
 152   if (!res)
 153     res = const_cast<char *>(s) + internal_strlen(s);
 154   return res;
 155 }
 156
 157 char *internal_strrchr(const char *s, int c) {
 158   const char *res = nullptr;
 159   for (uptr i = 0; s[i]; i++) {
 160     if (s[i] == c) res = s + i;
 161   }
 162   return const_cast<char *>(res);
 163 }
 164
 165 uptr internal_strlen(const char *s) {
 166   uptr i = 0;
 167   while (s[i]) i++;
 168   return i;
 169 }
 170
 171 uptr internal_strlcat(char *dst, const char *src, uptr maxlen) {
 172   const uptr srclen = internal_strlen(src);
 173   const uptr dstlen = internal_strnlen(dst, maxlen);
 174   if (dstlen == maxlen) return maxlen + srclen;
 175   if (srclen < maxlen - dstlen) {
 176     internal_memmove(dst + dstlen, src, srclen + 1);
 177   } else {
 178     internal_memmove(dst + dstlen, src, maxlen - dstlen - 1);
 179     dst[maxlen - 1] = '\0';
 180   }
 181   return dstlen + srclen;
 182 }
 183
 184 char *internal_strncat(char *dst, const char *src, uptr n) {
 185   uptr len = internal_strlen(dst);
 186   uptr i;
 187   for (i = 0; i < n && src[i]; i++)
 188     dst[len + i] = src[i];
 189   dst[len + i] = 0;
 190   return dst;
 191 }
 192
 193 uptr internal_strlcpy(char *dst, const char *src, uptr maxlen) {
 194   const uptr srclen = internal_strlen(src);
 195   if (srclen < maxlen) {
 196     internal_memmove(dst, src, srclen + 1);
 197   } else if (maxlen != 0) {
 198     internal_memmove(dst, src, maxlen - 1);
 199     dst[maxlen - 1] = '\0';
 200   }
 201   return srclen;
 202 }
 203
 204 char *internal_strncpy(char *dst, const char *src, uptr n) {
 205   uptr i;
 206   for (i = 0; i < n && src[i]; i++)
 207     dst[i] = src[i];
 208   internal_memset(dst + i, '\0', n - i);
 209   return dst;
 210 }
 211
 212 uptr internal_strnlen(const char *s, uptr maxlen) {
 213   uptr i = 0;
 214   while (i < maxlen && s[i]) i++;
 215   return i;
 216 }
 217
 218 char *internal_strstr(const char *haystack, const char *needle) {
 219   // This is O(N^2), but we are not using it in hot places.
 220   uptr len1 = internal_strlen(haystack);
 221   uptr len2 = internal_strlen(needle);
 222   if (len1 < len2) return nullptr;
 223   for (uptr pos = 0; pos <= len1 - len2; pos++) {
 224     if (internal_memcmp(haystack + pos, needle, len2) == 0)
 225       return const_cast<char *>(haystack) + pos;
 226   }
 227   return nullptr;
 228 }
 229
 230 s64 internal_simple_strtoll(const char *nptr, const char **endptr, int base) {
 231   CHECK_EQ(base, 10);
 232   while (IsSpace(*nptr)) nptr++;
 233   int sgn = 1;
 234   u64 res = 0;
 235   bool have_digits = false;
 236   char *old_nptr = const_cast<char *>(nptr);
 237   if (*nptr == '+') {
 238     sgn = 1;
 239     nptr++;
 240   } else if (*nptr == '-') {
 241     sgn = -1;
 242     nptr++;
 243   }
 244   while (IsDigit(*nptr)) {
 245     res = (res <= UINT64_MAX / 10) ? res * 10 : UINT64_MAX;
 246     int digit = ((*nptr) - '0');
 247     res = (res <= UINT64_MAX - digit) ? res + digit : UINT64_MAX;
 248     have_digits = true;
 249     nptr++;
 250   }
 251   if (endptr) {
 252     *endptr = (have_digits) ? const_cast<char *>(nptr) : old_nptr;
 253   }
 254   if (sgn > 0) {
 255     return (s64)(Min((u64)INT64_MAX, res));
 256   } else {
 257     return (res > INT64_MAX) ? INT64_MIN : ((s64)res * -1);
 258   }
 259 }
 260
 261 bool mem_is_zero(const char *beg, uptr size) {
 262   CHECK_LE(size, 1ULL << FIRST_32_SECOND_64(30, 40));  // Sanity check.
 263   const char *end = beg + size;
 264   uptr *aligned_beg = (uptr *)RoundUpTo((uptr)beg, sizeof(uptr));
 265   uptr *aligned_end = (uptr *)RoundDownTo((uptr)end, sizeof(uptr));
 266   uptr all = 0;
 267   // Prologue.
 268   for (const char *mem = beg; mem < (char*)aligned_beg && mem < end; mem++)
 269     all |= *mem;
 270   // Aligned loop.
 271   for (; aligned_beg < aligned_end; aligned_beg++)
 272     all |= *aligned_beg;
 273   // Epilogue.
 274   if ((char *)aligned_end >= beg) {
 275     for (const char *mem = (char *)aligned_end; mem < end; mem++) all |= *mem;
 276   }
 277   return all == 0;
 278 }
 279
 280 } // namespace __sanitizer