/* p_lx_sh.cpp --

   This file is part of the UPX executable compressor.

   Copyright (C) Markus Franz Xaver Johannes Oberhumer
   Copyright (C) Laszlo Molnar
   Copyright (C) John F. Reiser
   All Rights Reserved.

   UPX and the UCL library are free software; you can redistribute them
   and/or modify them under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Markus F.X.J. Oberhumer              Laszlo Molnar
   <markus@oberhumer.com>               <ezerotven+github@gmail.com>

   John F. Reiser
   <jreiser@users.sourceforge.net>
 */


#include "conf.h"

#include "file.h"
#include "filter.h"
#include "packer.h"
#include "p_elf.h"
#include "p_unix.h"
#include "p_lx_exc.h"
#include "p_lx_sh.h"

#define PT_LOAD     Elf_LE32_Phdr::PT_LOAD


/*************************************************************************
//
**************************************************************************/

static const CLANG_FORMAT_DUMMY_STATEMENT
#include "stub/i386-linux.elf.shell-entry.h"
static const CLANG_FORMAT_DUMMY_STATEMENT
#include "stub/i386-linux.elf.shell-fold.h"


PackLinuxI386sh::PackLinuxI386sh(InputFile *f) :
    super(f), o_shname(0), l_shname(0)
{
}

PackLinuxI386sh::~PackLinuxI386sh()
{
}

void
PackLinuxI386sh::buildLoader(Filter const *ft)
{
    unsigned const sz_fold = sizeof(stub_i386_linux_elf_shell_fold);
    MemBuffer buf(sz_fold);
    memcpy(buf, stub_i386_linux_elf_shell_fold, sz_fold);

    checkPatch(nullptr, 0, 0, 0);  // reset
    patch_le32(buf,sz_fold,"UPX3",l_shname);
    patch_le32(buf,sz_fold,"UPX2",o_shname);

    // get fresh filter
    Filter fold_ft = *ft;
    fold_ft.init(ft->id, ft->addvalue);
    int preferred_ctos[2] = { ft->cto, -1 };
    fold_ft.preferred_ctos = preferred_ctos;

    // filter
    optimizeFilter(&fold_ft, buf, sz_fold);
    unsigned fold_hdrlen = sizeof(l_info) + sizeof(Elf32_Ehdr) +
        sizeof(Elf32_Phdr) * get_te16(&((Elf32_Ehdr const *)(void *)buf)->e_phnum);
    if (0 == get_le32(buf + fold_hdrlen)) {
        // inconsistent SIZEOF_HEADERS in *.lds (ld, binutils)
        fold_hdrlen = upx::umax(0x80u, fold_hdrlen);
    }
    bool success = fold_ft.filter(buf + fold_hdrlen, sz_fold - fold_hdrlen);
    UNUSED(success);

    buildLinuxLoader(
        stub_i386_linux_elf_shell_entry, sizeof(stub_i386_linux_elf_shell_entry),
        buf, sz_fold, ft );
}

void PackLinuxI386sh::patchLoader() { }


bool PackLinuxI386sh::getShellName(char *buf)
{
    exetype = -1;
    l_shname = (int) strcspn(buf, " \t\n\v\f\r");
    buf[l_shname] = 0;
    static char const *const shname[] = { // known shells that accept "-c" arg
        "ash", "bash", "bsh", "csh", "ksh", "pdksh", "sh", "tcsh", "zsh",
        "python", "python2", "python3",
        nullptr
    };
    const char *bname = strrchr(buf, '/');
    if (bname == nullptr)
        return false;
    for (int j = 0; nullptr != shname[j]; ++j) {
        if (0 == strcmp(shname[j], bname + 1)) {
            bool const s = bool(super::canPack());
            if (s) {
                opt->o_unix.blocksize = blocksize = file_size;
            }
            unsigned size = fi->st_size();
            if (size > (125<<10)) { // 128KB but allow 3KB for environment
                printWarn(fi->getName(), "Likely E2BIG for size=%u", size);
                return false;
            }
            return s;
        }
    }
    return false;
}


tribool PackLinuxI386sh::canPack()
{
#if defined(__linux__)  //{
    // only compress i386sh scripts when running under Linux
    char buf[512];

    fi->readx(buf, sizeof(buf));
    fi->seek(0, SEEK_SET);
    buf[sizeof(buf) - 1] = 0;
    if (!memcmp(buf, "#!/", 3)) {                       // #!/bin/sh
        o_shname = 2;
        return getShellName(&buf[o_shname]);
    }
    else if (!memcmp(buf, "#! /", 4)) {                 // #! /bin/sh
        o_shname = 3;
        return getShellName(&buf[o_shname]);
    }
#endif  //}
    return false;
}


void
PackLinuxI386sh::pack1(OutputFile *fo, Filter &)
{
    generateElfHdr(fo, stub_i386_linux_elf_shell_fold, 0x08048000);
}

off_t
PackLinuxI386sh::pack3(OutputFile *fo, Filter &ft)
{
    return elfout.phdr[0].p_filesz = super::pack3(fo,ft);
}

/* vim:set ts=4 sw=4 et: */
