Having found oneself in a situation where TLS 1.2 is about to become a hard
requirement, an opportunity to upgrade a very old (7.15.1) curl/libcurl has
arisen.

The environment that needs upgrade is an OpenServer 5.0.7 system. GNU tools
are available, and it has been possible to build a number of newer tools in
this environment. In fact, it was possible to build up to curl 7.53.1 with
only a modicum of fuss needed to adapt to the present state of the build
environment; the openssl-1.0.2o.tar.gz LTS release built fine with no issue.

As curl 7.53.1 is by far new enough to support TLS 1.2, one could stop with
this success, but, it seems prudent to assure a capability of building up to
current, not only to address vulnerabilities between 7.53.1 and current, but
also, to prepare for building follow-on releases per future vulnerabilities.

As gcc on this system as been more reliable than the native cc for this sort
of effort, use of the GNU tools created an issue in include/curl/system.h.
It was not terribly difficult to resolve this issue with a change based on
the fall-through code:

#else
/* generic "safe guess" on old 32 bit style */
# define CURL_TYPEOF_CURL_OFF_T long
# define CURL_FORMAT_CURL_OFF_T "ld"
# define CURL_FORMAT_CURL_OFF_TU "lu"
# define CURL_SUFFIX_CURL_OFF_T L
# define CURL_SUFFIX_CURL_OFF_TU UL
# define CURL_TYPEOF_CURL_SOCKLEN_T int
#endif

The change incorporates use of a _SCO_DS define mentioned along with a code
sample that "illustrates how to test for various SCO UNIX platforms when
doing conditional compilations".

  http://osr507doc.sco.com/en/DevSysoview/Ccompil.html#Multiplat

The patch is:

--- ../curl-7.60.0.orig/include/curl/system.h 2018-05-07 04:18:02.000000000 -0500
+++ ./include/curl/system.h 2018-06-18 02:11:08.000000000 -0500
@@ -320,6 +320,14 @@
 # define CURL_PULL_SYS_TYPES_H 1
 # define CURL_PULL_SYS_SOCKET_H 1

+#elif defined(_SCO_DS) /* SCO OpenServer 5 */
+# define CURL_TYPEOF_CURL_OFF_T long
+# define CURL_FORMAT_CURL_OFF_T "ld"
+# define CURL_FORMAT_CURL_OFF_TU "lu"
+# define CURL_SUFFIX_CURL_OFF_T L
+# define CURL_SUFFIX_CURL_OFF_TU UL
+# define CURL_TYPEOF_CURL_SOCKLEN_T int
+
 /* ===================================== */
 /* KEEP MSVC THE PENULTIMATE ENTRY */
 /* ===================================== */

The patch is untested at this time, because the source still will not build
without additional changes, but, in fact, this system is an old 32 bit
operating system, so is probably reasonable for the moment.

Currently, a build of 7.60.0 blows up as shown here:

warnless.c:101:4: #error "SIZEOF_CURL_OFF_T not defined"
warnless.c: In function `curlx_uztoso':
warnless.c:192: error: `CURL_MASK_SCOFFT' undeclared (first use in this function)
warnless.c:192: error: (Each undeclared identifier is reported only once
warnless.c:192: error: for each function it appears in.)
make[2]: *** [libcurl_la-warnless.lo] Error 1
make[2]: Leaving directory `/csdi/admin/kevinb/src/curl/curl-7.60.0/lib'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/csdi/admin/kevinb/src/curl/curl-7.60.0/lib'
make: *** [all-recursive] Error 1

As SIZEOF_CURL_OFF_T appears to be conceptually affected by the configure
script, lib/curl_setup.h, lib/curl_config.h, and other files unique to
other build environments, it seemed prudent to request some advice as to
how to begin to tackle the rest of the patch, particularly since I am not
familiar with this code base, and, since it would be nice to come up with
an acceptable project patch for this build environment.

Could anyone suggest how/where it might be prudent to begin unraveling the
aforementioned issues? If additional information can make it easier to
give such advice, I'm more than willing to provide it. I think this is
the correct mailing list, but feel free to direct me to a more
appropriate venue.

Thanks in advance.

-- 
Kevin R. Bulgrien, Network/Software Engineer
http://www.systemsdesignusa.com
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