Added safe_v?snprintf() for platforms with unsafe versions.

git-svn-id: https://smartmontools.svn.sourceforge.net/svnroot/smartmontools/trunk@2021 4ea69e1a-61f1-4043-bf83-b5c94c648137

sm5/CHANGELOG

 CHANGELOG for smartmontools
 
-$Id: CHANGELOG,v 1.488 2004/11/06 15:58:53 chrfranke Exp $
+$Id: CHANGELOG,v 1.489 2004/11/06 17:51:28 chrfranke Exp $
 
 The most recent version of this file is:
 http://cvs.sourceforge.net/viewcvs.py/smartmontools/sm5/CHANGELOG?sortby=date&view=markup
@@ -31,6 +31,9 @@ NOTES FOR FUTURE RELEASES: see TODO file.
 
 <ADDITIONS TO THE CHANGE LOG SHOULD BE ADDED JUST BELOW HERE, PLEASE>
 
+  [CF] Added safe_v?snprintf() for platforms using v?snprintf()
+       with non standard behaviour on overflow (Windows, old Linux)
+
   [CF] smartd: Added message if check power mode spins up disk.
 
   [CF] Windows: Added support for READ_LOG on WinNT4 using undocumented

sm5/configure.in

 #
-# $Id: configure.in,v 1.108 2004/11/05 21:42:34 chrfranke Exp $
+# $Id: configure.in,v 1.109 2004/11/06 17:51:28 chrfranke Exp $
 #
 dnl Process this file with autoconf to produce a configure script.
 AC_PREREQ(2.50)
@@ -7,7 +7,7 @@ AC_INIT(smartmontools, 5.34, smartmontools-support@lists.sourceforge.net)
 AC_CONFIG_SRCDIR(smartctl.c)
 
 smartmontools_configure_date=`date -u +"%Y/%m/%d %T %Z"`
-smartmontools_cvs_tag=`echo '$Id: configure.in,v 1.108 2004/11/05 21:42:34 chrfranke Exp $'`
+smartmontools_cvs_tag=`echo '$Id: configure.in,v 1.109 2004/11/06 17:51:28 chrfranke Exp $'`
 smartmontools_release_date=2004/09/10
 smartmontools_release_time="04:11:35 UTC"
 
@@ -70,11 +70,23 @@ AC_CHECK_FUNCS([sigset])
 AC_CHECK_FUNCS([strtoull])
 AC_CHECK_FUNCS([uname])
 
+# Check whether snprintf appends null char and returns expected length on overflow
+AH_TEMPLATE(HAVE_WORKING_SNPRINTF, [Define to 1 if the `snprintf' function is sane])
+AC_MSG_CHECKING([for working snprintf])
+AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]], [[ char buf[]="ABCDEFGHI";
+               int i=snprintf(buf,8,"12345678"); return !(!buf[7] && i==8); ]])],
+              [libc_have_working_snprintf=yes], [libc_have_working_snprintf=no])
+AC_SUBST(libc_have_working_snprintf)
+if test "$libc_have_working_snprintf" = "yes"; then
+  AC_DEFINE(HAVE_WORKING_SNPRINTF)
+fi
+AC_MSG_RESULT([$libc_have_working_snprintf])
+
 # check for __attribute__((packed))
 AH_TEMPLATE(HAVE_ATTR_PACKED, [Define to 1 if C compiler supports __attribute__((packed))])
 AC_MSG_CHECKING([whether C compiler supports __attribute__((packed))])
-AC_TRY_COMPILE(, struct a { int b; } __attribute__((packed));,
-               gcc_have_attr_packed=yes, gcc_have_attr_packed=no)
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM(, [[struct a { int b; } __attribute__((packed));]])],
+                  [gcc_have_attr_packed=yes], [gcc_have_attr_packed=no])
 AC_SUBST(gcc_have_attr_packed)
 if test "$gcc_have_attr_packed" = "yes"; then
   AC_DEFINE(HAVE_ATTR_PACKED)

sm5/utility.c

@@ -41,7 +41,7 @@
 #include "utility.h"
 
 // Any local header files should be represented by a CVSIDX just below.
-const char* utility_c_cvsid="$Id: utility.c,v 1.55 2004/09/16 08:46:04 ballen4705 Exp $"
+const char* utility_c_cvsid="$Id: utility.c,v 1.56 2004/11/06 17:51:28 chrfranke Exp $"
 CONFIG_H_CVSID INT64_H_CVSID UTILITY_H_CVSID;
 
 const char * packet_types[] = {
@@ -592,4 +592,32 @@ void MsecToText(unsigned int msec, char *txt){
 }
 
 
+#ifndef HAVE_WORKING_SNPRINTF
+// Some versions of (v)snprintf() don't append null char on overflow (MSVCRT.DLL),
+// and/or return -1 on overflow (old Linux).
+// Below are sane replacements substituted by #define in utility.h.
 
+#undef vsnprintf
+#if defined(_WIN32) && defined(_MSC_VER)
+#define vsnprintf _vsnprintf
+#endif
+
+int safe_vsnprintf(char *buf, int size, const char *fmt, va_list ap)
+{
+  if (size <= 0)
+    return 0;
+  vsnprintf(buf, size, fmt, ap);
+  buf[size-1] = 0;
+  return strlen(buf); // Note: cannot detect for overflow, not necessary here.
+}
+
+int safe_snprintf(char *buf, int size, const char *fmt, ...)
+{
+  int i; va_list ap;
+  va_start(ap, fmt);
+  i = safe_vsnprintf(buf, size, fmt, ap);
+  va_end(ap);
+  return i;
+}
+
+#endif

sm5/utility.cpp

@@ -41,7 +41,7 @@
 #include "utility.h"
 
 // Any local header files should be represented by a CVSIDX just below.
-const char* utility_c_cvsid="$Id: utility.cpp,v 1.55 2004/09/16 08:46:04 ballen4705 Exp $"
+const char* utility_c_cvsid="$Id: utility.cpp,v 1.56 2004/11/06 17:51:28 chrfranke Exp $"
 CONFIG_H_CVSID INT64_H_CVSID UTILITY_H_CVSID;
 
 const char * packet_types[] = {
@@ -592,4 +592,32 @@ void MsecToText(unsigned int msec, char *txt){
 }
 
 
+#ifndef HAVE_WORKING_SNPRINTF
+// Some versions of (v)snprintf() don't append null char on overflow (MSVCRT.DLL),
+// and/or return -1 on overflow (old Linux).
+// Below are sane replacements substituted by #define in utility.h.
 
+#undef vsnprintf
+#if defined(_WIN32) && defined(_MSC_VER)
+#define vsnprintf _vsnprintf
+#endif
+
+int safe_vsnprintf(char *buf, int size, const char *fmt, va_list ap)
+{
+  if (size <= 0)
+    return 0;
+  vsnprintf(buf, size, fmt, ap);
+  buf[size-1] = 0;
+  return strlen(buf); // Note: cannot detect for overflow, not necessary here.
+}
+
+int safe_snprintf(char *buf, int size, const char *fmt, ...)
+{
+  int i; va_list ap;
+  va_start(ap, fmt);
+  i = safe_vsnprintf(buf, size, fmt, ap);
+  va_end(ap);
+  return i;
+}
+
+#endif

sm5/utility.h

@@ -25,15 +25,19 @@
 #ifndef UTILITY_H_
 #define UTILITY_H_
 
-#define UTILITY_H_CVSID "$Id: utility.h,v 1.40 2004/10/13 20:18:03 chrfranke Exp $\n"
+#define UTILITY_H_CVSID "$Id: utility.h,v 1.41 2004/11/06 17:51:28 chrfranke Exp $\n"
 
 #include <time.h>
 #include <sys/types.h> // for regex.h (according to POSIX)
 #include <regex.h>
 
-#if defined(_WIN32) && defined(_MSC_VER)
-#define snprintf  _snprintf
-#define vsnprintf  _vsnprintf
+#ifndef HAVE_WORKING_SNPRINTF
+// Substitute by safe replacement functions
+#include <stdarg.h>
+int safe_snprintf(char *buf, int size, const char *fmt, ...);
+int safe_vsnprintf(char *buf, int size, const char *fmt, va_list ap);
+#define snprintf  safe_snprintf
+#define vsnprintf safe_vsnprintf
 #endif
 
 // Utility function prints current date and time and timezone into a