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Subject: Building libssh2 1.2.4 through 1.8.0 on host type i686-pc-sco3.2v5.0.7

Building libssh2 1.2.4 through 1.8.0 on host type i686-pc-sco3.2v5.0.7

From: Kevin R. Bulgrien <kevinb_at_systemsdesignusa.com>
Date: Thu, 17 Jan 2019 16:33:04 -0600 (CST)

During attempts to build curl 7.63.0 (and earlier), to resolve known
vulnerabilities, difficulty was encountered with libssh2 releases
above 1.2.4 as follows:

    $ CFLAGS="-static" ./configure \
      --with-libssl-prefix=/usr/local \
        --prefix=/csdi/src/sco507/root/usr/local
    ...
      version: 1.8.0
      Host type: i686-pc-sco3.2v5.0.7
      Install prefix: /csdi/src/sco507/root/usr/local
      Compiler: gcc
      Compiler flags: -static -D_XOPEN_SOURCE_EXTENDED
      Library types: Shared=yes, Static=yes
      Crypto library: OpenSSL (AES-CTR: no)
      Clear memory: unsupported
      Debug build: no
      Build examples: no
      Path to sshd: /etc/sshd (only for self-tests)
      zlib compression: no

    $ make
    Making all in src
    ...
    Making all in example
    make[1]: Entering directory
      `/csdi/src/sco507/libssh2/libssh2-1.2.4/example'
    make all-am
    make[2]: Entering directory
      `/csdi/src/sco507/libssh2/libssh2-1.2.4/example'
    source='direct_tcpip.c' object='direct_tcpip.o' libtool=no \
    DEPDIR=.deps depmode=gcc /bin/ksh ../depcomp \
    gcc -DHAVE_CONFIG_H -I../include -I../example
      -I/csdi/admin/kevinb/include -static -c direct_tcpip.c
    direct_tcpip.c: In function `main':
    direct_tcpip.c:48: `socklen_t' undeclared (first use in this function)
    direct_tcpip.c:48: (Each undeclared identifier is reported only once
    direct_tcpip.c:48: for each function it appears in.)
    direct_tcpip.c:48: parse error before `sinlen'
    direct_tcpip.c:166: `sinlen' undeclared (first use in this function)
    make[2]: *** [direct_tcpip.o] Error 1
    make[2]: Leaving directory
      `/csdi/src/sco507/libssh2/libssh2-1.2.4/example'
    make[1]: *** [all] Error 2
    make[1]: Leaving directory
      `/csdi/src/sco507/libssh2/libssh2-1.2.4/example'
    make: *** [all-recursive] Error 1

socklen_t is not defined on this host type, but, it is noted that other
FOSS projects workaround this limitation. For example, in curl 7.61.0
and above, the file include/curl/system.h works around this with a
typedef that kicks in when SCO_DS is not defined:

    #elif defined(__GNUC__) && !defined(_SCO_DS)
    ...
    #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

It could be helpful for the libssh2 project to consider a socklen_t
workaround for these systems. The following patch against the
1.8.0 release resolves compilation issues on this platform:

$ cat libssh2-1.8.0-i686-pc-sco3.2v5.0.7.patch
diff -ru libssh2-1.8.0/include/libssh2.h
libssh2-1.8.0-patch1/include/libssh2.h
--- libssh2-1.8.0/include/libssh2.h 2016-10-25 01:44:34.000000000 -0500
+++ libssh2-1.8.0-patch1/include/libssh2.h 2019-01-17 14:53:11.000000000
-0600
@@ -114,6 +114,15 @@
 # endif /* LIBSSH2_WIN32 */
 #endif /* LIBSSH2_API */

+#if (defined(_SCO_DS))
+/*
+ * socklen_t is not defined in this system, but, it is noted that other FOSS
+ * projects (i.e. curl include/curl/system.h) define socklen_t in the
+ * following way to work around build issues:
+ */
+typedef int socklen_t;
+#endif
+
 #ifdef HAVE_SYS_UIO_H
 # include <sys/uio.h>
 #endif

The aforementioned patch is clearly very specific to the host type, but any
equivalent patch that may be more generic is certainly better than the
current situation.

To build libssh2 on this host type, once the patch is applied, another
build issue occurs:

    $ patch -p1 -i ../libssh2-1.8.0-i686-pc-sco3.2v5.0.7.patch
    patching file include/libssh2.h
    $ CFLAGS="-static" ./configure \
        --with-libssl-prefix=/usr/local \
          --prefix=/csdi/src/sco507/root/usr/local
    $ make
    Making all in src
    make[1]: Entering directory
      `/csdi/admin/kevinb/src/libssh2/libssh2-1.8.0/src'
    make all-am
    make[2]: Entering directory
      `/csdi/admin/kevinb/src/libssh2/libssh2-1.8.0/src'
      CC channel.lo
    In file included from libssh2_priv.h:86,
                     from channel.c:41:
    /usr/include/sys/uio.h:76: parse error before `off_t'
    /usr/include/sys/uio.h:76: warning: no semicolon at end of struct or
      union
    /usr/include/sys/uio.h:80: parse error before `}'
    /usr/include/sys/uio.h:80: warning: data definition has no type or
      storage class
    In file included from libssh2_priv.h:86,
                     from channel.c:41:
    /usr/include/sys/uio.h:96: parse error before `readv'
    /usr/include/sys/uio.h:96: warning: data definition has no type or
      storage class
    /usr/include/sys/uio.h:97: parse error before `writev'
    /usr/include/sys/uio.h:97: warning: data definition has no type or
      storage class
    make[2]: *** [channel.lo] Error 1
    make[2]: Leaving directory
      `/csdi/admin/kevinb/src/libssh2/libssh2-1.8.0/src'
    make[1]: *** [all] Error 2
    make[1]: Leaving directory
      `/csdi/admin/kevinb/src/libssh2/libssh2-1.8.0/src'
    make: *** [all-recursive] Error 1

off_t is mentioned in the same curl code (include/curl/system.h)
where the socklen_t assignment was that helped curl compile. The fix
for off_t, however, was not so simple as patching in a typedef as the
error actually occurs in a SCO file (/usr/include/sys/uio.h).

In /usr/include/sys/uio.h, the problematic off_t assignment only
occurs when _XOPEN_SOURCE_EXTENDED is not defined. It is not yet
clear how _XOPEN_SOURCE_EXTENDED might get defined properly, but, the
libssh2 build error is avoided by manually setting the define:

    CFLAGS="-D_XOPEN_SOURCE_EXTENDED".

Once the off_t problem is resolved, make issues a new error:

    $ CC= CFLAGS="-static -D_XOPEN_SOURCE_EXTENDED" ./configure \
        --with-libssl-prefix=/usr/local \
          --prefix=/csdi/src/sco507/root/usr/local
    $ make
    ...
    In file included from /usr/include/sys/termios.h:31,
                     from /usr/include/xpg4v2/termios.h:31,
                     from /usr/include/termios.h:7,
                     from x11.c:23:
    /usr/include/sys/termio.h:584: `LDNAMEMAX' undeclared here (not in a function)
    x11.c: In function `main':
    x11.c:431: `SHUT_RDWR' undeclared (first use in this function)
    x11.c:431: (Each undeclared identifier is reported only once
    x11.c:431: for each function it appears in.)
    make[2]: *** [Makefile:620: x11.o] Error 1
    make[2]: Leaving directory
      '/csdi/src/sco507/libssh2/libssh2-1.8.0/example'
    make[1]: *** [Makefile:441: all] Error 2
    make[1]: Leaving directory
      '/csdi/src/sco507/libssh2/libssh2-1.8.0/example'
    make: *** [Makefile:546: all-recursive] Error 1

Note that x11.c is in an "example" directory, so it is simple enough to
resolve this issue by disable building the examples:

    $ ./configure --help | grep example
      --enable-examples-build Build example applications (this is the default)
      --disable-examples-build
                                Do not build example applications

    $ CC= CFLAGS="-static -D_XOPEN_SOURCE_EXTENDED" ./configure \
        --with-libssl-prefix=/usr/local --disable-examples-build \
          --prefix=/csdi/src/sco507/root/usr/local
    $ make

At this point, the build succeeds with the socklen_t patch being the
only source change.

If nothing else, and if the patch or an equivalent one is not applied,
at least perhaps this post should help anyone else being in such an
unfortunate situation as having to build on this host type. (We
wanted to build libssh2 to get curl's sftp capability.)

Regards,

Kevin R. Bulgrien
_______________________________________________
libssh2-devel https://cool.haxx.se/cgi-bin/mailman/listinfo/libssh2-devel
Received on 2019-01-17

the libssh2 team