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 | |
38 | extern "C" { |
39 | |
40 | size_t my_strlen(const char* s) { |
41 | size_t len = 0; |
42 | while (*s++) len++; |
43 | return len; |
44 | } |
45 | |
46 | int 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 | |
59 | int 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. |
78 | bool 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. |
99 | unsigned 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|). |
118 | void 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 | |
123 | const 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 | |
131 | const 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 | |
141 | void* 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. |
155 | const 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 | |
177 | const 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 | |
192 | void my_memset(void* ip, char c, size_t len) { |
193 | char* p = (char*) ip; |
194 | while (len--) |
195 | *p++ = c; |
196 | } |
197 | |
198 | size_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 | |
215 | size_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 | |
227 | int 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 | |