1 | /* Copyright (c) 1996 by Internet Software Consortium. |
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2 | * |
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3 | * Permission to use, copy, modify, and distribute this software for any |
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4 | * purpose with or without fee is hereby granted, provided that the above |
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5 | * copyright notice and this permission notice appear in all copies. |
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6 | * |
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7 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
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8 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
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9 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
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10 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
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11 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
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12 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
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13 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
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14 | * SOFTWARE. |
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15 | */ |
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16 | |
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17 | #if defined(LIBC_SCCS) && !defined(lint) |
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18 | static char rcsid[] = "$Id$"; |
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19 | #endif /* LIBC_SCCS and not lint */ |
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20 | |
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21 | #include <sys/param.h> |
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22 | #include <sys/types.h> |
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23 | #include <sys/socket.h> |
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24 | #include <netinet/in.h> |
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25 | #include <arpa/inet.h> |
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26 | #include <arpa/nameser.h> |
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27 | #include <errno.h> |
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28 | #include <stdio.h> |
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29 | #include <string.h> |
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30 | |
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31 | #define SPRINTF(x) ((size_t)sprintf x) |
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32 | |
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33 | /* |
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34 | * WARNING: Don't even consider trying to compile this on a system where |
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35 | * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. |
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36 | */ |
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37 | |
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38 | static const char *inet_ntop4 __P((const u_char *src, char *dst, size_t size)); |
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39 | static const char *inet_ntop6 __P((const u_char *src, char *dst, size_t size)); |
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40 | |
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41 | /* char * |
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42 | * inet_ntop(af, src, dst, size) |
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43 | * convert a network format address to presentation format. |
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44 | * return: |
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45 | * pointer to presentation format address (`dst'), or NULL (see errno). |
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46 | * author: |
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47 | * Paul Vixie, 1996. |
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48 | */ |
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49 | const char * |
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50 | inet_ntop(af, src, dst, size) |
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51 | int af; |
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52 | const void *src; |
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53 | char *dst; |
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54 | size_t size; |
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55 | { |
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56 | switch (af) { |
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57 | case AF_INET: |
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58 | return (inet_ntop4(src, dst, size)); |
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59 | case AF_INET6: |
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60 | return (inet_ntop6(src, dst, size)); |
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61 | default: |
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62 | errno = EAFNOSUPPORT; |
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63 | return (NULL); |
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64 | } |
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65 | /* NOTREACHED */ |
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66 | } |
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67 | |
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68 | /* const char * |
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69 | * inet_ntop4(src, dst, size) |
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70 | * format an IPv4 address, more or less like inet_ntoa() |
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71 | * return: |
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72 | * `dst' (as a const) |
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73 | * notes: |
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74 | * (1) uses no statics |
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75 | * (2) takes a u_char* not an in_addr as input |
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76 | * author: |
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77 | * Paul Vixie, 1996. |
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78 | */ |
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79 | static const char * |
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80 | inet_ntop4(src, dst, size) |
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81 | const u_char *src; |
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82 | char *dst; |
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83 | size_t size; |
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84 | { |
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85 | static const char fmt[] = "%u.%u.%u.%u"; |
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86 | char tmp[sizeof "255.255.255.255"]; |
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87 | |
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88 | if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) { |
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89 | errno = ENOSPC; |
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90 | return (NULL); |
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91 | } |
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92 | strcpy(dst, tmp); |
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93 | return (dst); |
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94 | } |
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95 | |
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96 | /* const char * |
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97 | * inet_ntop6(src, dst, size) |
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98 | * convert IPv6 binary address into presentation (printable) format |
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99 | * author: |
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100 | * Paul Vixie, 1996. |
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101 | */ |
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102 | static const char * |
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103 | inet_ntop6(src, dst, size) |
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104 | const u_char *src; |
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105 | char *dst; |
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106 | size_t size; |
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107 | { |
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108 | /* |
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109 | * Note that int32_t and int16_t need only be "at least" large enough |
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110 | * to contain a value of the specified size. On some systems, like |
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111 | * Crays, there is no such thing as an integer variable with 16 bits. |
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112 | * Keep this in mind if you think this function should have been coded |
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113 | * to use pointer overlays. All the world's not a VAX. |
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114 | */ |
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115 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; |
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116 | struct { int base, len; } best, cur; |
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117 | u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; |
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118 | int i; |
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119 | |
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120 | /* |
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121 | * Preprocess: |
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122 | * Copy the input (bytewise) array into a wordwise array. |
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123 | * Find the longest run of 0x00's in src[] for :: shorthanding. |
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124 | */ |
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125 | memset(words, '\0', sizeof words); |
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126 | for (i = 0; i < NS_IN6ADDRSZ; i++) |
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127 | words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); |
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128 | best.base = -1; |
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129 | cur.base = -1; |
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130 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
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131 | if (words[i] == 0) { |
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132 | if (cur.base == -1) |
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133 | cur.base = i, cur.len = 1; |
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134 | else |
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135 | cur.len++; |
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136 | } else { |
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137 | if (cur.base != -1) { |
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138 | if (best.base == -1 || cur.len > best.len) |
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139 | best = cur; |
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140 | cur.base = -1; |
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141 | } |
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142 | } |
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143 | } |
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144 | if (cur.base != -1) { |
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145 | if (best.base == -1 || cur.len > best.len) |
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146 | best = cur; |
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147 | } |
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148 | if (best.base != -1 && best.len < 2) |
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149 | best.base = -1; |
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150 | |
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151 | /* |
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152 | * Format the result. |
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153 | */ |
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154 | tp = tmp; |
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155 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { |
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156 | /* Are we inside the best run of 0x00's? */ |
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157 | if (best.base != -1 && i >= best.base && |
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158 | i < (best.base + best.len)) { |
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159 | if (i == best.base) |
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160 | *tp++ = ':'; |
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161 | continue; |
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162 | } |
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163 | /* Are we following an initial run of 0x00s or any real hex? */ |
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164 | if (i != 0) |
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165 | *tp++ = ':'; |
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166 | /* Is this address an encapsulated IPv4? */ |
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167 | if (i == 6 && best.base == 0 && |
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168 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { |
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169 | if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) |
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170 | return (NULL); |
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171 | tp += strlen(tp); |
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172 | break; |
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173 | } |
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174 | tp += SPRINTF((tp, "%x", words[i])); |
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175 | } |
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176 | /* Was it a trailing run of 0x00's? */ |
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177 | if (best.base != -1 && (best.base + best.len) == |
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178 | (NS_IN6ADDRSZ / NS_INT16SZ)) |
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179 | *tp++ = ':'; |
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180 | *tp++ = '\0'; |
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181 | |
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182 | /* |
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183 | * Check for overflow, copy, and we're done. |
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184 | */ |
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185 | if ((size_t)(tp - tmp) > size) { |
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186 | errno = ENOSPC; |
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187 | return (NULL); |
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188 | } |
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189 | strcpy(dst, tmp); |
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190 | return (dst); |
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191 | } |
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