1// Copyright (c) 2012, Google Inc.
2// All rights reserved.
3//
4// Redistribution and use in source and binary forms, with or without
5// modification, are permitted provided that the following conditions are
6// met:
7//
8// * Redistributions of source code must retain the above copyright
9// notice, this list of conditions and the following disclaimer.
10// * Redistributions in binary form must reproduce the above
11// copyright notice, this list of conditions and the following disclaimer
12// in the documentation and/or other materials provided with the
13// distribution.
14// * Neither the name of Google Inc. nor the names of its
15// contributors may be used to endorse or promote products derived from
16// this software without specific prior written permission.
17//
18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30// This source file provides replacements for libc functions that we need. If
31// we call the libc functions directly we risk crashing in the dynamic linker
32// as it tries to resolve uncached PLT entries.
33
34#include "common/linux/linux_libc_support.h"
35
36#include <stddef.h>
37
38extern "C" {
39
40size_t my_strlen(const char* s) {
41 size_t len = 0;
42 while (*s++) len++;
43 return len;
44}
45
46int my_strcmp(const char* a, const char* b) {
47 for (;;) {
48 if (*a < *b)
49 return -1;
50 else if (*a > *b)
51 return 1;
52 else if (*a == 0)
53 return 0;
54 a++;
55 b++;
56 }
57}
58
59int my_strncmp(const char* a, const char* b, size_t len) {
60 for (size_t i = 0; i < len; ++i) {
61 if (*a < *b)
62 return -1;
63 else if (*a > *b)
64 return 1;
65 else if (*a == 0)
66 return 0;
67 a++;
68 b++;
69 }
70
71 return 0;
72}
73
74// Parse a non-negative integer.
75// result: (output) the resulting non-negative integer
76// s: a NUL terminated string
77// Return true iff successful.
78bool my_strtoui(int* result, const char* s) {
79 if (*s == 0)
80 return false;
81 int r = 0;
82 for (;; s++) {
83 if (*s == 0)
84 break;
85 const int old_r = r;
86 r *= 10;
87 if (*s < '0' || *s > '9')
88 return false;
89 r += *s - '0';
90 if (r < old_r)
91 return false;
92 }
93
94 *result = r;
95 return true;
96}
97
98// Return the length of the given unsigned integer when expressed in base 10.
99unsigned my_uint_len(uintmax_t i) {
100 if (!i)
101 return 1;
102
103 int len = 0;
104 while (i) {
105 len++;
106 i /= 10;
107 }
108
109 return len;
110}
111
112// Convert an unsigned integer to a string
113// output: (output) the resulting string is written here. This buffer must be
114// large enough to hold the resulting string. Call |my_uint_len| to get the
115// required length.
116// i: the unsigned integer to serialise.
117// i_len: the length of the integer in base 10 (see |my_uint_len|).
118void my_uitos(char* output, uintmax_t i, unsigned i_len) {
119 for (unsigned index = i_len; index; --index, i /= 10)
120 output[index - 1] = '0' + (i % 10);
121}
122
123const char* my_strchr(const char* haystack, char needle) {
124 while (*haystack && *haystack != needle)
125 haystack++;
126 if (*haystack == needle)
127 return haystack;
128 return (const char*) 0;
129}
130
131const char* my_strrchr(const char* haystack, char needle) {
132 const char* ret = NULL;
133 while (*haystack) {
134 if (*haystack == needle)
135 ret = haystack;
136 haystack++;
137 }
138 return ret;
139}
140
141void* my_memchr(const void* src, int needle, size_t src_len) {
142 const unsigned char* p = (const unsigned char*)src;
143 const unsigned char* p_end = p + src_len;
144 for (; p < p_end; ++p) {
145 if (*p == needle)
146 return (void*)p;
147 }
148 return NULL;
149}
150
151// Read a hex value
152// result: (output) the resulting value
153// s: a string
154// Returns a pointer to the first invalid charactor.
155const char* my_read_hex_ptr(uintptr_t* result, const char* s) {
156 uintptr_t r = 0;
157
158 for (;; ++s) {
159 if (*s >= '0' && *s <= '9') {
160 r <<= 4;
161 r += *s - '0';
162 } else if (*s >= 'a' && *s <= 'f') {
163 r <<= 4;
164 r += (*s - 'a') + 10;
165 } else if (*s >= 'A' && *s <= 'F') {
166 r <<= 4;
167 r += (*s - 'A') + 10;
168 } else {
169 break;
170 }
171 }
172
173 *result = r;
174 return s;
175}
176
177const char* my_read_decimal_ptr(uintptr_t* result, const char* s) {
178 uintptr_t r = 0;
179
180 for (;; ++s) {
181 if (*s >= '0' && *s <= '9') {
182 r *= 10;
183 r += *s - '0';
184 } else {
185 break;
186 }
187 }
188 *result = r;
189 return s;
190}
191
192void my_memset(void* ip, char c, size_t len) {
193 char* p = (char*) ip;
194 while (len--)
195 *p++ = c;
196}
197
198size_t my_strlcpy(char* s1, const char* s2, size_t len) {
199 size_t pos1 = 0;
200 size_t pos2 = 0;
201
202 while (s2[pos2] != '\0') {
203 if (pos1 + 1 < len) {
204 s1[pos1] = s2[pos2];
205 pos1++;
206 }
207 pos2++;
208 }
209 if (len > 0)
210 s1[pos1] = '\0';
211
212 return pos2;
213}
214
215size_t my_strlcat(char* s1, const char* s2, size_t len) {
216 size_t pos1 = 0;
217
218 while (pos1 < len && s1[pos1] != '\0')
219 pos1++;
220
221 if (pos1 == len)
222 return pos1;
223
224 return pos1 + my_strlcpy(s1 + pos1, s2, len - pos1);
225}
226
227int my_isspace(int ch) {
228 // Matches the C locale.
229 const char spaces[] = " \t\f\n\r\t\v";
230 for (size_t i = 0; i < sizeof(spaces); i++) {
231 if (ch == spaces[i])
232 return 1;
233 }
234 return 0;
235}
236
237} // extern "C"
238