src/mesa/main/vsnprintf.c

   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 <sys/param.h>
  28 #include <sys/types.h>
  29 #include <sys/mman.h>
  30 #include <signal.h>
  31 #include <stdio.h>
  32 #if __STDC__
  33 #include <stdarg.h>
  34 #include <stdlib.h>
  35 #else
  36 #include <varargs.h>
  37 #endif
  38 #include <setjmp.h>
  39 #include <unistd.h>
  40 #include <string.h>
  41
  42 #ifndef roundup
  43 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
  44 #endif
  45
  46 #ifdef __sgi
  47 #define size_t ssize_t
  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( int a )
  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 int
 105 #if __STDC__
 106 vsnprintf(char *str, size_t n, char const *fmt, va_list ap)
 107 #else
 108 vsnprintf(str, n, fmt, ap)
 109         char *str;
 110         size_t n;
 111         char *fmt;
 112         char *ap;
 113 #endif
 114 {
 115         struct sigaction osa, nsa;
 116         char *p;
 117         int ret = n + 1;        /* if we bail, indicated we overflowed */
 118
 119         memset(&nsa, 0, sizeof nsa);
 120         nsa.sa_handler = mcatch;
 121         sigemptyset(&nsa.sa_mask);
 122
 123         p = msetup(str, n);
 124         if (p == NULL) {
 125                 *str = '\0';
 126                 return 0;
 127         }
 128         if (sigsetjmp(bail, 1) == 0) {
 129                 if (sigaction(SIGSEGV, &nsa, &osa) == -1) {
 130                         mcleanup(str, n, p);
 131                         return (0);
 132                 }
 133                 ret = vsprintf(p, fmt, ap);
 134         }
 135         mcleanup(str, n, p);
 136         (void) sigaction(SIGSEGV, &osa, NULL);
 137         return (ret);
 138 }
 139
 140 int
 141 #if __STDC__
 142 snprintf(char *str, size_t n, char const *fmt, ...)
 143 #else
 144 snprintf(str, n, fmt, va_alist)
 145         char *str;
 146         size_t n;
 147         char *fmt;
 148         va_dcl
 149 #endif
 150 {
 151         va_list ap;
 152 #if __STDC__
 153         va_start(ap, fmt);
 154 #else
 155         va_start(ap);
 156 #endif
 157
 158         return (vsnprintf(str, n, fmt, ap));
 159         va_end(ap);
 160 }
 161
 162
 163