Created attachment 599310 [details]
SPEC file

Description of problem:

I am requesting that the "ksh" package maintainer for Fedora considers building using shared libshell/libast libraries to reduce redundant code in memory when we have multiple copies of ksh running.

Currently, the ast-ksh package is compiled using the default static configuration of rolling libshell.a into a very large ksh binary:

   ls -lh:
       -rwxr-xr-x 1 root root 1.6M Apr 14 11:47 /bin/ksh
   ldd:
        linux-vdso64.so.1 =>  (0x00000fff8a6a0000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00000fff8a660000)
        libm.so.6 => /lib64/libm.so.6 (0x00000fff8a560000)
        libc.so.6 => /lib64/libc.so.6 (0x00000fff8a370000)
        /lib64/ld64.so.1 (0x000000005a2a0000)

That's your big boy: 1.6 MegaBytes for a shell that is not bash.

Linking pmain.o to libshell.so and libast (plus libcmd, libcoshell, and libdll) however produces a very small ksh binary and we can allow the dynamic linker to share one copy of the ast libraries in memory:

   ls -lh:
      -rwxr-xr-x 1 root root 5.3K Jul 20 12:07 /bin/ksh
      -rwxr-xr-x 1 root root 1.2M Jul 20 12:07 /usr/lib64/libast-ast.so
      -rwxr-xr-x 1 root root 300K Jul 20 12:07 /usr/lib64/libast-cmd.so
      -rwxr-xr-x 1 root root  42K Jul 20 12:07 /usr/lib64/libast-coshell.so
      -rwxr-xr-x 1 root root  24K Jul 20 12:07 /usr/lib64/libast-dll.so
      -rwxr-xr-x 1 root root 866K Jul 20 12:07 /usr/lib64/libast-shell.so
   ldd:
        linux-vdso64.so.1 =>  (0x00000fff8da40000)
        libm.so.6 => /lib64/libm.so.6 (0x00000fff8d930000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00000fff8d900000)
        libast-shell.so => /usr/lib64/libast-shell.so (0x00000fff8d820000)
        libast-ast.so => /usr/lib64/libast-ast.so (0x00000fff8d6e0000)
        libc.so.6 => /lib64/libc.so.6 (0x00000fff8d4f0000)
        /lib64/ld64.so.1 (0x000000004e7d0000)
        libast-dll.so => /usr/lib64/libast-dll.so (0x00000fff8d4d0000)
        libast-coshell.so => /usr/lib64/libast-coshell.so (0x00000fff8d4b0000)
        libast-cmd.so => /usr/lib64/libast-cmd.so (0x00000fff8d450000)
        libnsl.so.1 => /lib64/libnsl.so.1 (0x00000fff8d410000) 

5.3 kiloBytes, that's more like it.


Version-Release number of selected component (if applicable):

20120229-2


Additional info:

Please refer to the rpm spec file attached for one of the ways (please pardon my personal spec file, it obviously is not up to the level of professional spec files for the Fedora project) to go about building ksh with shared ast libraries. The linking steps were taken directly from the makefile in the ast-ksh source tree.

There is also a small patch attached as well, used by the spec file, for what appears to be an accidental omission of the -fPIC flag on three source file compilation rules in the file ksh93/Mamfile that would otherwise prevent you from creating the shared object file libshell.so successfully as it would complain these three object files cannot have relocatable code.

Another note: only Debian seems to build the AT&T ksh in this manner of shared objects for libast these days, both Fedora and OpenSUSE build ksh using the default Mamfiles resulting in the huge ksh binary. Also wish AT&T research team would switch to using autoconf/automake/make rather than their build system...