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Rev | Author | Line No. | Line |
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55 | pj | 1 | /* |
2 | * Revision 12: http://theos.com/~deraadt/snprintf.c |
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3 | * |
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4 | * Copyright (c) 1997 Theo de Raadt |
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5 | * |
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6 | * Redistribution and use in source and binary forms, with or without |
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7 | * modification, are permitted provided that the following conditions |
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8 | * are met: |
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9 | * 1. Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * 2. Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * |
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15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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25 | */ |
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26 | |||
27 | #include <sys/param.h> |
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28 | #include <sys/types.h> |
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29 | #include <sys/mman.h> |
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30 | #include <signal.h> |
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31 | #include <stdio.h> |
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32 | #if __STDC__ |
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33 | #include <stdarg.h> |
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34 | #include <stdlib.h> |
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35 | #else |
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36 | #include <varargs.h> |
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37 | #endif |
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38 | #include <setjmp.h> |
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39 | #include <unistd.h> |
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40 | #include <string.h> |
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41 | |||
42 | #ifndef roundup |
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43 | #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) |
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44 | #endif |
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45 | |||
46 | #ifdef __sgi |
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47 | #define size_t ssize_t |
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48 | #endif |
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49 | |||
50 | static int pgsize; |
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51 | static char *curobj; |
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52 | static int caught; |
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53 | static sigjmp_buf bail; |
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54 | |||
55 | #define EXTRABYTES 2 /* XXX: why 2? you don't want to know */ |
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56 | |||
57 | static char * |
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58 | msetup(str, n) |
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59 | char *str; |
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60 | size_t n; |
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61 | { |
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62 | char *e; |
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63 | |||
64 | if (n == 0) |
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65 | return NULL; |
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66 | if (pgsize == 0) |
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67 | pgsize = getpagesize(); |
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68 | curobj = (char *)malloc(n + EXTRABYTES + pgsize * 2); |
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69 | if (curobj == NULL) |
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70 | return NULL; |
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71 | e = curobj + n + EXTRABYTES; |
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72 | e = (char *)roundup((unsigned long)e, pgsize); |
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73 | if (mprotect(e, pgsize, PROT_NONE) == -1) { |
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74 | free(curobj); |
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75 | curobj = NULL; |
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76 | return NULL; |
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77 | } |
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78 | e = e - n - EXTRABYTES; |
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79 | *e = '\0'; |
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80 | return (e); |
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81 | } |
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82 | |||
83 | static void |
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84 | mcatch( int a ) |
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85 | { |
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86 | siglongjmp(bail, 1); |
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87 | } |
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88 | |||
89 | static void |
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90 | mcleanup(str, n, p) |
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91 | char *str; |
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92 | size_t n; |
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93 | char *p; |
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94 | { |
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95 | strncpy(str, p, n-1); |
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96 | str[n-1] = '\0'; |
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97 | if (mprotect((caddr_t)(p + n + EXTRABYTES), pgsize, |
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98 | PROT_READ|PROT_WRITE|PROT_EXEC) == -1) |
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99 | mprotect((caddr_t)(p + n + EXTRABYTES), pgsize, |
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100 | PROT_READ|PROT_WRITE); |
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101 | free(curobj); |
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102 | } |
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103 | |||
104 | int |
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105 | #if __STDC__ |
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106 | vsnprintf(char *str, size_t n, char const *fmt, va_list ap) |
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107 | #else |
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108 | vsnprintf(str, n, fmt, ap) |
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109 | char *str; |
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110 | size_t n; |
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111 | char *fmt; |
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112 | char *ap; |
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113 | #endif |
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114 | { |
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115 | struct sigaction osa, nsa; |
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116 | char *p; |
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117 | int ret = n + 1; /* if we bail, indicated we overflowed */ |
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118 | |||
119 | memset(&nsa, 0, sizeof nsa); |
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120 | nsa.sa_handler = mcatch; |
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121 | sigemptyset(&nsa.sa_mask); |
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122 | |||
123 | p = msetup(str, n); |
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124 | if (p == NULL) { |
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125 | *str = '\0'; |
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126 | return 0; |
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127 | } |
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128 | if (sigsetjmp(bail, 1) == 0) { |
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129 | if (sigaction(SIGSEGV, &nsa, &osa) == -1) { |
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130 | mcleanup(str, n, p); |
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131 | return (0); |
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132 | } |
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133 | ret = vsprintf(p, fmt, ap); |
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134 | } |
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135 | mcleanup(str, n, p); |
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136 | (void) sigaction(SIGSEGV, &osa, NULL); |
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137 | return (ret); |
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138 | } |
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139 | |||
140 | int |
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141 | #if __STDC__ |
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142 | snprintf(char *str, size_t n, char const *fmt, ...) |
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143 | #else |
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144 | snprintf(str, n, fmt, va_alist) |
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145 | char *str; |
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146 | size_t n; |
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147 | char *fmt; |
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148 | va_dcl |
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149 | #endif |
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150 | { |
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151 | va_list ap; |
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152 | #if __STDC__ |
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153 | va_start(ap, fmt); |
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154 | #else |
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155 | va_start(ap); |
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156 | #endif |
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157 | |||
158 | return (vsnprintf(str, n, fmt, ap)); |
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159 | va_end(ap); |
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160 | } |
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161 | |||
162 | |||
163 |