/*      $NetBSD: kobj_rename.c,v 1.3 2020/02/20 22:52:10 joerg Exp $    */

/*-
 * Copyright (c) 2010 Antti Kantee.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kobj_rename.c,v 1.3 2020/02/20 22:52:10 joerg Exp $");

#define ELFSIZE ARCH_ELFSIZE

#include <sys/param.h>
#include <sys/exec_elf.h>
#include <sys/kmem.h>
#include <sys/kobj.h>
#include <sys/systm.h>

#include <rump/rump.h>

/*
 * Mangle symbols into rump kernel namespace.  This means
 * putting "rumpns" in front of select symbols.
 * See src/sys/rump/Makefile.rump for more details on the rump kernel
 * namespace.
 */
const char *norentab[] = {
        "RUMP",
        "rump",
        "__",
        "_GLOBAL_OFFSET_TABLE",
        ".TOC.",
};
static int
norename(const char *name)
{
        unsigned i;

        for (i = 0; i < __arraycount(norentab); i++) {
                if (strncmp(norentab[i], name, strlen(norentab[i])) == 0)
                        return 1;
        }
        return 0;
}

#define RUMPNS "rumpns_"
int
kobj_renamespace(Elf_Sym *symtab, size_t symcount,
        char **strtab, size_t *strtabsz)
{
        Elf_Sym *sym;
        char *worktab, *newtab;
        size_t worktabsz, worktabidx;
        unsigned i;
        const size_t prefixlen = strlen(RUMPNS);
        static int warned;

        if (!rump_nativeabi_p() && !warned) {
                printf("warning: kernel ABI not supported on this arch\n");
                warned = 1;
        }

        /* allocate space for worst-case stringtab */
        worktabsz = *strtabsz + symcount * prefixlen;
        worktab = kmem_alloc(worktabsz, KM_SLEEP);

        /* now, adjust stringtab into temporary space */
#define WORKTABP (worktab + worktabidx)
        for (i = 0, worktabidx = 0; i < symcount; i++) {
                const char *fromname;

                sym = &symtab[i];
                if (sym->st_name == 0) {
                        continue;
                }

                fromname = *strtab + sym->st_name;
                sym->st_name = worktabidx;

                if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL ||
                    norename(fromname)) {
                        strcpy(WORKTABP, fromname);
                        worktabidx += strlen(fromname) + 1;
                } else {
                        strcpy(WORKTABP, RUMPNS);
                        worktabidx += prefixlen;
                        strcpy(WORKTABP, fromname);
                        worktabidx += strlen(fromname) + 1;
                }
                KASSERT(worktabidx <= worktabsz);
        }
#undef WORKTABP

        /*
         * Finally, free old strtab, allocate new one, and copy contents.
         */
        kmem_free(*strtab, *strtabsz);
        *strtab = NULL; /* marvin the paradroid 999 */
        newtab = kmem_alloc(worktabidx, KM_SLEEP);
        memcpy(newtab, worktab, worktabidx);

        kmem_free(worktab, worktabsz);

        *strtab = newtab;
        *strtabsz = worktabidx;

        return 0;
}