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
17namespace __sanitizer {
18
19s64 internal_atoll(const char *nptr) {
20  return internal_simple_strtoll(nptr, nullptr, 10);
21}
22
23void *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
31void *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
40int 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
49void *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
57void *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
75void *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
99uptr 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
108char* 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
116int 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
128int 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
140char* 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
150char *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
157char *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
165uptr internal_strlen(const char *s) {
166  uptr i = 0;
167  while (s[i]) i++;
168  return i;
169}
170
171uptr 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
184char *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
193uptr 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
204char *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
212uptr internal_strnlen(const char *s, uptr maxlen) {
213  uptr i = 0;
214  while (i < maxlen && s[i]) i++;
215  return i;
216}
217
218char *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
230s64 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
261bool 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
281