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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 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 |