Compile time and runtime checks for library compatibility

libisoburn/trunk/libisoburn/burn_wrap.c

@@ -49,7 +49,89 @@ extern struct isoburn *isoburn_list_start; /* in isoburn.c */
 
 int isoburn_initialize(char msg[1024], int flag)
 {
- int major, minor, micro;
+ int major, minor, micro, bad_match= 0;
+
+
+/* First two ugly compile time checks for header version compatibility.
+   If everthing matches, then they produce no C code. In case of mismatch,
+   intentionally faulty C code will be inserted.
+*/
+
+#ifdef iso_lib_header_version_major
+/* The minimum requirement of libisoburn towards the libisofs header
+   at compile time is defined in libisoburn/libisoburn.h :
+     isoburn_libisofs_req_major
+     isoburn_libisofs_req_minor
+     isoburn_libisofs_req_micro
+   It gets compared against the version macros in libisofs/libisofs.h :
+     iso_lib_header_version_major
+     iso_lib_header_version_minor
+     iso_lib_header_version_micro
+   If the header is too old then the following code shall cause failure of
+   cdrskin compilation rather than to allow production of a program with
+   unpredictable bugs or memory corruption.
+   The compiler messages supposed to appear in this case are:
+      error: 'LIBISOFS_MISCONFIGURATION' undeclared (first use in this function)
+      error: 'INTENTIONAL_ABORT_OF_COMPILATION__HEADERFILE_libisofs_dot_h_TOO_OLD__SEE_libisoburn_dot_h_and_burn_wrap_dot_h' undeclared (first use in this function)
+      error: 'LIBISOFS_MISCONFIGURATION_' undeclared (first use in this function)
+*/
+/* The indendation is an advise of man gcc to help old compilers ignoring */
+ #if isoburn_libisofs_req_major > iso_lib_header_version_major
+ #define Isoburn_libisofs_dot_h_too_olD 1
+ #endif
+ #if isoburn_libisofs_req_major == iso_lib_header_version_major && isoburn_libisofs_req_minor > iso_lib_header_version_minor
+ #define Isoburn_libisofs_dot_h_too_olD 1
+ #endif
+ #if isoburn_libisofs_req_minor == iso_lib_header_version_minor && isoburn_libisofs_req_micro > iso_lib_header_version_micro
+ #define Isoburn_libisofs_dot_h_too_olD 1
+ #endif
+
+#ifdef Isoburn_libisofs_dot_h_too_olD
+LIBISOFS_MISCONFIGURATION = 0;
+INTENTIONAL_ABORT_OF_COMPILATION__HEADERFILE_libisofs_dot_h_TOO_OLD__SEE_libisoburn_dot_h_and_burn_wrap_dot_h = 0;
+LIBISOFS_MISCONFIGURATION_ = 0;
+#endif
+
+#endif /* iso_lib_header_version_major */
+
+/* The minimum requirement of libisoburn towards the libburn header
+   at compile time is defined in libisoburn/libisoburn.h :
+     isoburn_libburn_req_major
+     isoburn_libburn_req_minor
+     isoburn_libburn_req_micro
+   It gets compared against the version macros in libburn/libburn.h :
+     burn_header_version_major
+     burn_header_version_minor
+     burn_header_version_micro
+   If the header is too old then the following code shall cause failure of
+   cdrskin compilation rather than to allow production of a program with
+   unpredictable bugs or memory corruption.
+   The compiler messages supposed to appear in this case are:
+      error: 'LIBBURN_MISCONFIGURATION' undeclared (first use in this function)
+      error: 'INTENTIONAL_ABORT_OF_COMPILATION__HEADERFILE_libburn_dot_h_TOO_OLD__SEE_libisoburn_dot_h_and_burn_wrap_dot_h' undeclared (first use in this function)
+      error: 'LIBBURN_MISCONFIGURATION_' undeclared (first use in this function)
+*/
+
+/* The indendation is an advise of man gcc to help old compilers ignoring */
+ #if isoburn_libburn_req_major > burn_header_version_major
+ #define Isoburn_libburn_dot_h_too_olD 1
+ #endif
+ #if isoburn_libburn_req_major == burn_header_version_major && isoburn_libburn_req_minor > burn_header_version_minor
+ #define Isoburn_libburn_dot_h_too_olD 1
+ #endif
+ #if isoburn_libburn_req_minor == burn_header_version_minor && isoburn_libburn_req_micro > burn_header_version_micro
+ #define Isoburn_libburn_dot_h_too_olD 1
+ #endif
+
+#ifdef Isoburn_libburn_dot_h_too_olD
+LIBBURN_MISCONFIGURATION = 0;
+INTENTIONAL_ABORT_OF_COMPILATION__HEADERFILE_libburn_dot_h_TOO_OLD__SEE_libisoburn_dot_h_and_burn_wrap_dot_h = 0;
+LIBBURN_MISCONFIGURATION_ = 0;
+#endif
+
+/* End of ugly compile time tests (scroll up for explanation) */
+
+
 
  msg[0]= 0;
  if(iso_init()<0) {
@@ -57,33 +139,56 @@ int isoburn_initialize(char msg[1024], int flag)
    return(0);
  }
  iso_lib_version(&major, &minor, &micro);
- sprintf(msg+strlen(msg), "libisofs-%d.%d.%d , ", major, minor, micro);
+ sprintf(msg+strlen(msg), "libisofs-%d.%d.%d ", major, minor, micro);
-
+#ifdef iso_lib_header_version_major
- /* >>> check for suitability of library */
+ if(iso_lib_is_compatible(iso_lib_header_version_major,
+                          iso_lib_header_version_minor,
+                          iso_lib_header_version_micro)) {
+   sprintf(msg+strlen(msg), "ok, ");
+ } else {
+   sprintf(msg+strlen(msg),"- TOO OLD -, need at least libisofs-%d.%d.%d ,\n",
+           iso_lib_header_version_major, iso_lib_header_version_minor,
+           iso_lib_header_version_micro);
+   bad_match= 1;
+ }
+#else
+ if(iso_lib_is_compatible(isoburn_libisofs_req_major,
+                          isoburn_libisofs_req_minor,
+                          isoburn_libisofs_req_micro)) {
+   sprintf(msg+strlen(msg), "suspicious, ");
+ } else {
+   sprintf(msg+strlen(msg),"- TOO OLD -, need at least libisofs-%d.%d.%d ,\n",
+           isoburn_libisofs_req_major, isoburn_libisofs_req_minor,
+           isoburn_libisofs_req_micro);
+   bad_match= 1;
+ }
+#endif /* ! iso_lib_header_version_major */
 
  if(!burn_initialize()) {
    sprintf(msg+strlen(msg), "Cannot initialize libburn\n");
    return(0);
  }
  burn_version(&major, &minor, &micro);
- sprintf(msg+strlen(msg), "libburn-%d.%d.%d , ", major, minor, micro);
+ sprintf(msg+strlen(msg), "libburn-%d.%d.%d ", major, minor, micro);
  if(major > burn_header_version_major
     || (major == burn_header_version_major
         && (minor > burn_header_version_minor
             || (minor == burn_header_version_minor
                 && micro >= burn_header_version_micro)))) {
-   ; /* ok */
+   sprintf(msg+strlen(msg), "ok, ");
  } else {
    sprintf(msg+strlen(msg), "- TOO OLD -, need at least libburn-%d.%d.%d ,\n",
            burn_header_version_major, burn_header_version_minor,
            burn_header_version_micro);
-   return(0);
+   bad_match= 1;
  }
 
- isoburn_destroy_all(&isoburn_list_start, 0); /* isoburn_list_start= NULL */
- 
  isoburn_version(&major, &minor, &micro);
- sprintf(msg+strlen(msg), "libisoburn-%d.%d.%d", major, minor, micro);
+ sprintf(msg+strlen(msg), "for libisoburn-%d.%d.%d", major, minor, micro);
+ if(bad_match)
+   return(0);
+
+ isoburn_destroy_all(&isoburn_list_start, 0); /* isoburn_list_start= NULL */
  return(1);
 }
 

libisoburn/trunk/libisoburn/libisoburn.h

@@ -138,21 +138,6 @@ int isoburn_initialize(char msg[1024], int flag);
 int isoburn_is_compatible(int major, int minor, int micro, int flag);
 
 
-/** These three release version numbers tell the revision of this header file
-    and of the API it describes. They are memorized by applications at build
-    time.
-*/
-#define isoburn_header_version_major  0
-#define isoburn_header_version_minor  0
-#define isoburn_header_version_micro  1
-/** Note:
-    Above version numbers are also recorded in configure.ac because libtool
-    wants them as parameters at build time.
-    For the library compatibility check ISOBURN_*_VERSION in configure.ac
-    are not decisive. Only the three numbers above do matter.
-*/
-
-
 /** Obtain the three release version numbers of the library. These are the
     numbers encountered by the application when linking with libisoburn,
     i.e. possibly not before run time.
@@ -174,6 +159,77 @@ int isoburn_is_compatible(int major, int minor, int micro, int flag);
 */
 void isoburn_version(int *major, int *minor, int *micro);
 
+/** The minimum version of libisofs to be used with this version of libisoburn
+*/
+#define isoburn_libisofs_req_major  0
+#define isoburn_libisofs_req_minor  6
+#define isoburn_libisofs_req_micro  1
+
+/** The minimum version of libburn to be used with this version of libisoburn
+*/
+#define isoburn_libburn_req_major  0
+#define isoburn_libburn_req_minor  4
+#define isoburn_libburn_req_micro  2
+
+/** These three release version numbers tell the revision of this header file
+    and of the API it describes. They are memorized by applications at build
+    time.
+*/
+#define isoburn_header_version_major  0
+#define isoburn_header_version_minor  0
+#define isoburn_header_version_micro  1
+/** Note:
+    Above version numbers are also recorded in configure.ac because libtool
+    wants them as parameters at build time.
+    For the library compatibility check ISOBURN_*_VERSION in configure.ac
+    are not decisive. Only the three numbers above do matter.
+*/
+/** Usage discussion:
+
+Some developers of the libburnia project have differing
+opinions how to ensure the compatibility of libaries
+and applications.
+
+It is about whether to use at compile time and at runtime
+the version numbers isoburn_header_version_* provided here.
+Thomas Schmitt advises to use them.
+Vreixo Formoso advises to use other means.
+
+At compile time:
+
+Vreixo Formoso advises to leave proper version matching
+to properly programmed checks in the the application's
+build system, which will eventually refuse compilation.
+
+Thomas Schmitt advises to use the macros defined here
+for comparison with the application's requirements of
+library revisions and to eventually break compilation.
+
+Both advises are combinable. I.e. be master of your
+build system and have #if checks in the source code
+of your application, nevertheless.
+
+At runtime (via *_is_compatible()):
+
+Vreixo Formoso advises to compare the application's
+requirements of library revisions with the runtime
+library. This is to allow runtime libraries which are
+young enough for the application but too old for
+the lib*.h files seen at compile time.
+
+Thomas Schmitt advises to compare the header
+revisions defined here with the runtime library.
+This is to enforce a strictly monotonous chain
+of revisions from app to header to library,
+at the cost of excluding some older libraries.
+
+These two advises are mutually exclusive.
+
+For an implementation of the Thomas Schmitt approach,
+see libisoburn/burn_wrap.c : isoburn_initialize()
+
+*/
+
 
 /** Aquire a target drive by its filesystem path resp. libburn persistent
     address.

libisoburn/trunk/xorriso/make_xorriso_standalone.sh

@@ -134,14 +134,16 @@ copy_files libisofs/*.[ch] "$lone_dir"/libisofs
 # To get a common version.h 
 cat version.h.in >> "$lone_dir"/version.h.in
 
-sed -e 's/FNM_FILE_NAME/FNM_PATHNAME/g' \
-<libisofs/tree.c >"$lone_dir"/libisofs/tree.c
 
+# <<< obsoleted patchings
 
-# <<< obsoleted
 if test 1 = 0
 then
 
+# Change GNU macro name to POSIX name
+sed -e 's/FNM_FILE_NAME/FNM_PATHNAME/g' \
+  <libisofs/tree.c >"$lone_dir"/libisofs/tree.c
+
 # Filter out the semi-illegal TODO comments 
 ( cd "$lone_dir"/libisofs && grep '^[[:space:]]*//' *.[ch] | less )
 echo "Is it ok delete all shown //-lines ?"

libisoburn/trunk/xorriso/xorriso_timestamp.h

@@ -1 +1 @@
-#define Xorriso_timestamP "2008.01.31.152131"
+#define Xorriso_timestamP "2008.01.31.214647"

libisoburn/trunk/xorriso/xorrisoburn.h

@@ -17,6 +17,12 @@
 struct XorrisO;
 struct FindjoB;
 
+/* The minimum version of libisoburn to be used with this version of xorriso
+*/
+#define xorriso_libisoburn_req_major  0
+#define xorriso_libisoburn_req_minor  0
+#define xorriso_libisoburn_req_micro  1
+
 int Xorriso_startup_libraries(struct XorrisO *xorriso, int flag);
 
 /* @param flag bit0= global shutdown of libraries */