Damien Miller | 42b81ff | 1999-11-26 12:21:24 +1100 | [diff] [blame] | 1 | /* |
| 2 | * Revision 12: http://theos.com/~deraadt/snprintf.c |
| 3 | * |
| 4 | * Copyright (c) 1997 Theo de Raadt |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 25 | */ |
| 26 | |
| 27 | #include "config.h" |
| 28 | |
| 29 | #if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF) |
| 30 | |
| 31 | #include <sys/param.h> |
| 32 | #include <sys/types.h> |
| 33 | #include <sys/mman.h> |
| 34 | #include <signal.h> |
| 35 | #include <stdio.h> |
| 36 | #include <unistd.h> |
| 37 | #include <string.h> |
| 38 | #if __STDC__ |
| 39 | #include <stdarg.h> |
| 40 | #include <stdlib.h> |
| 41 | #else |
| 42 | #include <varargs.h> |
| 43 | #endif |
| 44 | #include <setjmp.h> |
| 45 | |
| 46 | #ifndef roundup |
| 47 | #define roundup (x, y) ((((x)+((y)-1))/(y))*(y)) |
| 48 | #endif |
| 49 | |
| 50 | static int pgsize; |
| 51 | static char *curobj; |
| 52 | static int caught; |
| 53 | static sigjmp_buf bail; |
| 54 | |
| 55 | #define EXTRABYTES 2 /* XXX: why 2? you don't want to know */ |
| 56 | |
| 57 | static char * |
| 58 | msetup(str, n) |
| 59 | char *str; |
| 60 | size_t n; |
| 61 | { |
| 62 | char *e; |
| 63 | |
| 64 | if (n == 0) |
| 65 | return NULL; |
| 66 | if (pgsize == 0) |
| 67 | pgsize = getpagesize(); |
| 68 | curobj = (char *)malloc(n + EXTRABYTES + pgsize * 2); |
| 69 | if (curobj == NULL) |
| 70 | return NULL; |
| 71 | e = curobj + n + EXTRABYTES; |
| 72 | e = (char *)roundup((unsigned long)e, pgsize); |
| 73 | if (mprotect(e, pgsize, PROT_NONE) == -1) { |
| 74 | free(curobj); |
| 75 | curobj = NULL; |
| 76 | return NULL; |
| 77 | } |
| 78 | e = e - n - EXTRABYTES; |
| 79 | *e = '\0'; |
| 80 | return (e); |
| 81 | } |
| 82 | |
| 83 | static void |
| 84 | mcatch() |
| 85 | { |
| 86 | siglongjmp(bail, 1); |
| 87 | } |
| 88 | |
| 89 | static void |
| 90 | mcleanup(str, n, p) |
| 91 | char *str; |
| 92 | size_t n; |
| 93 | char *p; |
| 94 | { |
| 95 | strncpy(str, p, n-1); |
| 96 | str[n-1] = '\0'; |
| 97 | if (mprotect((caddr_t)(p + n + EXTRABYTES), pgsize, |
| 98 | PROT_READ|PROT_WRITE|PROT_EXEC) == -1) |
| 99 | mprotect((caddr_t)(p + n + EXTRABYTES), pgsize, |
| 100 | PROT_READ|PROT_WRITE); |
| 101 | free(curobj); |
| 102 | } |
| 103 | |
| 104 | #if !defined(HAVE_SNPRINTF) |
| 105 | int |
| 106 | #if __STDC__ |
| 107 | snprintf(char *str, size_t n, char const *fmt, ...) |
| 108 | #else |
| 109 | snprintf(str, n, fmt, va_alist) |
| 110 | char *str; |
| 111 | size_t n; |
| 112 | char *fmt; |
| 113 | va_dcl |
| 114 | #endif |
| 115 | { |
| 116 | va_list ap; |
| 117 | #if __STDC__ |
| 118 | va_start(ap, fmt); |
| 119 | #else |
| 120 | va_start(ap); |
| 121 | #endif |
| 122 | |
| 123 | return (vsnprintf(str, n, fmt, ap)); |
| 124 | va_end(ap); |
| 125 | } |
| 126 | #endif /* !defined(HAVE_SNPRINTF) */ |
| 127 | |
| 128 | #if !defined(HAVE_VSNPRINTF) |
| 129 | int |
| 130 | vsnprintf(str, n, fmt, ap) |
| 131 | char *str; |
| 132 | size_t n; |
| 133 | char *fmt; |
| 134 | char *ap; |
| 135 | { |
| 136 | struct sigaction osa, nsa; |
| 137 | char *p; |
| 138 | int ret = n + 1; /* if we bail, indicated we overflowed */ |
| 139 | |
| 140 | memset(&nsa, 0, sizeof nsa); |
| 141 | nsa.sa_handler = mcatch; |
| 142 | sigemptyset(&nsa.sa_mask); |
| 143 | |
| 144 | p = msetup(str, n); |
| 145 | if (p == NULL) { |
| 146 | *str = '\0'; |
| 147 | return 0; |
| 148 | } |
| 149 | if (sigsetjmp(bail, 1) == 0) { |
| 150 | if (sigaction(SIGSEGV, &nsa, &osa) == -1) { |
| 151 | mcleanup(str, n, p); |
| 152 | return (0); |
| 153 | } |
| 154 | ret = vsprintf(p, fmt, ap); |
| 155 | } |
| 156 | mcleanup(str, n, p); |
| 157 | (void) sigaction(SIGSEGV, &osa, NULL); |
| 158 | return (ret); |
| 159 | } |
| 160 | #endif /* !defined(HAVE_VSNPRINTF) */ |
| 161 | |
| 162 | #endif /* !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF) */ |