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 // Do not redefine builtins; this file is defining the builtin replacements.
  14 #define SANITIZER_COMMON_NO_REDEFINE_BUILTINS
  15
  16 #include "sanitizer_allocator_internal.h"
  17 #include "sanitizer_common.h"
  18 #include "sanitizer_libc.h"
  19
  20 namespace __sanitizer {
  21
  22 s64 internal_atoll(const char *nptr) {
  23   return internal_simple_strtoll(nptr, nullptr, 10);
  24 }
  25
  26 void *internal_memchr(const void *s, int c, uptr n) {
  27   const char *t = (const char *)s;
  28   for (uptr i = 0; i < n; ++i, ++t)
  29     if (*t == c)
  30       return reinterpret_cast<void *>(const_cast<char *>(t));
  31   return nullptr;
  32 }
  33
  34 void *internal_memrchr(const void *s, int c, uptr n) {
  35   const char *t = (const char *)s;
  36   void *res = nullptr;
  37   for (uptr i = 0; i < n; ++i, ++t) {
  38     if (*t == c) res = reinterpret_cast<void *>(const_cast<char *>(t));
  39   }
  40   return res;
  41 }
  42
  43 int internal_memcmp(const void* s1, const void* s2, uptr n) {
  44   const char *t1 = (const char *)s1;
  45   const char *t2 = (const char *)s2;
  46   for (uptr i = 0; i < n; ++i, ++t1, ++t2)
  47     if (*t1 != *t2)
  48       return *t1 < *t2 ? -1 : 1;
  49   return 0;
  50 }
  51
  52 extern "C" {
  53 SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memcpy(void *dest,
  54                                                                 const void *src,
  55                                                                 uptr n) {
  56   char *d = (char*)dest;
  57   const char *s = (const char *)src;
  58   for (uptr i = 0; i < n; ++i)
  59     d[i] = s[i];
  60   return dest;
  61 }
  62
  63 SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memmove(
  64     void *dest, const void *src, uptr n) {
  65   char *d = (char*)dest;
  66   const char *s = (const char *)src;
  67   sptr i, signed_n = (sptr)n;
  68   CHECK_GE(signed_n, 0);
  69   if (d < s) {
  70     for (i = 0; i < signed_n; ++i)
  71       d[i] = s[i];
  72   } else {
  73     if (d > s && signed_n > 0) {
  74       for (i = signed_n - 1; i >= 0; --i) {
  75         d[i] = s[i];
  76       }
  77     }
  78   }
  79   return dest;
  80 }
  81
  82 SANITIZER_INTERFACE_ATTRIBUTE void *__sanitizer_internal_memset(void *s, int c,
  83                                                                 uptr n) {
  84   // Optimize for the most performance-critical case:
  85   if ((reinterpret_cast<uptr>(s) % 16) == 0 && (n % 16) == 0) {
  86     u64 *p = reinterpret_cast<u64*>(s);
  87     u64 *e = p + n / 8;
  88     u64 v = c;
  89     v |= v << 8;
  90     v |= v << 16;
  91     v |= v << 32;
  92     for (; p < e; p += 2)
  93       p[0] = p[1] = v;
  94     return s;
  95   }
  96   // The next line prevents Clang from making a call to memset() instead of the
  97   // loop below.
  98   // FIXME: building the runtime with -ffreestanding is a better idea. However
  99   // there currently are linktime problems due to PR12396.
 100   char volatile *t = (char*)s;
 101   for (uptr i = 0; i < n; ++i, ++t) {
 102     *t = c;
 103   }
 104   return s;
 105 }
 106 }  // extern "C"
 107
 108 uptr internal_strcspn(const char *s, const char *reject) {
 109   uptr i;
 110   for (i = 0; s[i]; i++) {
 111     if (internal_strchr(reject, s[i]))
 112       return i;
 113   }
 114   return i;
 115 }
 116
 117 char* internal_strdup(const char *s) {
 118   uptr len = internal_strlen(s);
 119   char *s2 = (char*)InternalAlloc(len + 1);
 120   internal_memcpy(s2, s, len);
 121   s2[len] = 0;
 122   return s2;
 123 }
 124
 125 int internal_strcmp(const char *s1, const char *s2) {
 126   while (true) {
 127     unsigned c1 = *s1;
 128     unsigned c2 = *s2;
 129     if (c1 != c2) return (c1 < c2) ? -1 : 1;
 130     if (c1 == 0) break;
 131     s1++;
 132     s2++;
 133   }
 134   return 0;
 135 }
 136
 137 int internal_strncmp(const char *s1, const char *s2, uptr n) {
 138   for (uptr i = 0; i < n; i++) {
 139     unsigned c1 = *s1;
 140     unsigned c2 = *s2;
 141     if (c1 != c2) return (c1 < c2) ? -1 : 1;
 142     if (c1 == 0) break;
 143     s1++;
 144     s2++;
 145   }
 146   return 0;
 147 }
 148
 149 char* internal_strchr(const char *s, int c) {
 150   while (true) {
 151     if (*s == (char)c)
 152       return const_cast<char *>(s);
 153     if (*s == 0)
 154       return nullptr;
 155     s++;
 156   }
 157 }
 158
 159 char *internal_strchrnul(const char *s, int c) {
 160   char *res = internal_strchr(s, c);
 161   if (!res)
 162     res = const_cast<char *>(s) + internal_strlen(s);
 163   return res;
 164 }
 165
 166 char *internal_strrchr(const char *s, int c) {
 167   const char *res = nullptr;
 168   for (uptr i = 0; s[i]; i++) {
 169     if (s[i] == c) res = s + i;
 170   }
 171   return const_cast<char *>(res);
 172 }
 173
 174 uptr internal_strlen(const char *s) {
 175   uptr i = 0;
 176   while (s[i]) i++;
 177   return i;
 178 }
 179
 180 uptr internal_strlcat(char *dst, const char *src, uptr maxlen) {
 181   const uptr srclen = internal_strlen(src);
 182   const uptr dstlen = internal_strnlen(dst, maxlen);
 183   if (dstlen == maxlen) return maxlen + srclen;
 184   if (srclen < maxlen - dstlen) {
 185     internal_memmove(dst + dstlen, src, srclen + 1);
 186   } else {
 187     internal_memmove(dst + dstlen, src, maxlen - dstlen - 1);
 188     dst[maxlen - 1] = '\0';
 189   }
 190   return dstlen + srclen;
 191 }
 192
 193 char *internal_strncat(char *dst, const char *src, uptr n) {
 194   uptr len = internal_strlen(dst);
 195   uptr i;
 196   for (i = 0; i < n && src[i]; i++)
 197     dst[len + i] = src[i];
 198   dst[len + i] = 0;
 199   return dst;
 200 }
 201
 202 wchar_t *internal_wcscpy(wchar_t *dst, const wchar_t *src) {
 203   wchar_t *dst_it = dst;
 204   do {
 205     *dst_it++ = *src++;
 206   } while (*src);
 207   return dst;
 208 }
 209
 210 uptr internal_strlcpy(char *dst, const char *src, uptr maxlen) {
 211   const uptr srclen = internal_strlen(src);
 212   if (srclen < maxlen) {
 213     internal_memmove(dst, src, srclen + 1);
 214   } else if (maxlen != 0) {
 215     internal_memmove(dst, src, maxlen - 1);
 216     dst[maxlen - 1] = '\0';
 217   }
 218   return srclen;
 219 }
 220
 221 char *internal_strncpy(char *dst, const char *src, uptr n) {
 222   uptr i;
 223   for (i = 0; i < n && src[i]; i++)
 224     dst[i] = src[i];
 225   internal_memset(dst + i, '\0', n - i);
 226   return dst;
 227 }
 228
 229 wchar_t *internal_wcsncpy(wchar_t *dst, const wchar_t *src, uptr n) {
 230   uptr i;
 231   for (i = 0; i < n && src[i]; ++i)
 232     dst[i] = src[i];
 233   internal_memset(dst + i, 0, (n - i) * sizeof(wchar_t));
 234   return dst;
 235 }
 236
 237 uptr internal_strnlen(const char *s, uptr maxlen) {
 238   uptr i = 0;
 239   while (i < maxlen && s[i]) i++;
 240   return i;
 241 }
 242
 243 char *internal_strstr(const char *haystack, const char *needle) {
 244   // This is O(N^2), but we are not using it in hot places.
 245   uptr len1 = internal_strlen(haystack);
 246   uptr len2 = internal_strlen(needle);
 247   if (len1 < len2) return nullptr;
 248   for (uptr pos = 0; pos <= len1 - len2; pos++) {
 249     if (internal_memcmp(haystack + pos, needle, len2) == 0)
 250       return const_cast<char *>(haystack) + pos;
 251   }
 252   return nullptr;
 253 }
 254
 255 s64 internal_simple_strtoll(const char *nptr, const char **endptr, int base) {
 256   CHECK_EQ(base, 10);
 257   while (IsSpace(*nptr)) nptr++;
 258   int sgn = 1;
 259   u64 res = 0;
 260   bool have_digits = false;
 261   char *old_nptr = const_cast<char *>(nptr);
 262   if (*nptr == '+') {
 263     sgn = 1;
 264     nptr++;
 265   } else if (*nptr == '-') {
 266     sgn = -1;
 267     nptr++;
 268   }
 269   while (IsDigit(*nptr)) {
 270     res = (res <= UINT64_MAX / 10) ? res * 10 : UINT64_MAX;
 271     int digit = ((*nptr) - '0');
 272     res = (res <= UINT64_MAX - digit) ? res + digit : UINT64_MAX;
 273     have_digits = true;
 274     nptr++;
 275   }
 276   if (endptr) {
 277     *endptr = (have_digits) ? const_cast<char *>(nptr) : old_nptr;
 278   }
 279   if (sgn > 0) {
 280     return (s64)(Min((u64)INT64_MAX, res));
 281   } else {
 282     return (res > INT64_MAX) ? INT64_MIN : ((s64)res * -1);
 283   }
 284 }
 285
 286 uptr internal_wcslen(const wchar_t *s) {
 287   uptr i = 0;
 288   while (s[i]) i++;
 289   return i;
 290 }
 291
 292 uptr internal_wcsnlen(const wchar_t *s, uptr maxlen) {
 293   uptr i = 0;
 294   while (i < maxlen && s[i]) i++;
 295   return i;
 296 }
 297
 298 bool mem_is_zero(const char *beg, uptr size) {
 299   CHECK_LE(size, 1ULL << FIRST_32_SECOND_64(30, 40));  // Sanity check.
 300   const char *end = beg + size;
 301   uptr *aligned_beg = (uptr *)RoundUpTo((uptr)beg, sizeof(uptr));
 302   uptr *aligned_end = (uptr *)RoundDownTo((uptr)end, sizeof(uptr));
 303   uptr all = 0;
 304   // Prologue.
 305   for (const char *mem = beg; mem < (char*)aligned_beg && mem < end; mem++)
 306     all |= *mem;
 307   // Aligned loop.
 308   for (; aligned_beg < aligned_end; aligned_beg++)
 309     all |= *aligned_beg;
 310   // Epilogue.
 311   if ((char *)aligned_end >= beg) {
 312     for (const char *mem = (char *)aligned_end; mem < end; mem++) all |= *mem;
 313   }
 314   return all == 0;
 315 }
 316
 317 } // namespace __sanitizer