/*-
 * Copyright 1996, 1997, 1998, 1999 John D. Polstra.
 * 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 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.
 *
 * $FreeBSD$
 */

/*
 * Dynamic linker for ELF.
 *
 * John Polstra <jdp@polstra.com>.
 */

#include <sys/param.h>
#include <sys/mman.h>
#include <sys/tls.h>

#include <machine/sysarch.h>
#include <machine/tls.h>

#include <dlfcn.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "debug.h"
#include "rtld.h"

/*
 * Process the special R_X86_64_COPY relocations in the main program.  These
 * copy data from a shared object into a region in the main program's BSS
 * segment.
 *
 * Returns 0 on success, -1 on failure.
 */
int
do_copy_relocations(Obj_Entry *dstobj)
{
    const Elf_Rela *relalim;
    const Elf_Rela *rela;
    int error = 0;

    assert(dstobj->mainprog);   /* COPY relocations are invalid elsewhere */

    if (dstobj->relro_protected)
        mprotect(dstobj->relro_page, dstobj->relro_size, PROT_READ | PROT_WRITE);

    relalim = (const Elf_Rela *) ((caddr_t) dstobj->rela + dstobj->relasize);
    for (rela = dstobj->rela;  rela < relalim;  rela++) {
        if (ELF_R_TYPE(rela->r_info) == R_X86_64_COPY) {
            void *dstaddr;
            const Elf_Sym *dstsym;
            const char *name;
            size_t size;
            const void *srcaddr;
            const Elf_Sym *srcsym;
            const Obj_Entry *srcobj, *defobj;
            SymLook req;
            int res;

            dstaddr = (void *) (dstobj->relocbase + rela->r_offset);
            dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
            name = dstobj->strtab + dstsym->st_name;
            size = dstsym->st_size;
            symlook_init(&req, name);
            req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
            req.flags = SYMLOOK_EARLY;

            for (srcobj = dstobj->next;  srcobj != NULL;  srcobj = srcobj->next) {
                res = symlook_obj(&req, srcobj);
                if (res == 0) {
                    srcsym = req.sym_out;
                    defobj = req.defobj_out;
                    break;
                }
            }

            if (srcobj == NULL) {
                _rtld_error("Undefined symbol \"%s\" referenced from COPY"
                  " relocation in %s", name, dstobj->path);
                error = -1;
                break;
            }

            srcaddr = (const void *) (defobj->relocbase + srcsym->st_value);
            memcpy(dstaddr, srcaddr, size);
        }
    }

    if (dstobj->relro_protected)
        mprotect(dstobj->relro_page, dstobj->relro_size, PROT_READ);

    return error;
}

/* Initialize the special GOT entries. */
void
init_pltgot(Obj_Entry *obj)
{
    if (obj->pltgot != NULL) {
        obj->pltgot[1] = (Elf_Addr) obj;
        obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
    }
}

/* Process the non-PLT relocations. */
int
reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
    RtldLockState *lockstate)
{
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        SymCache *cache;
        const Elf_Sym *def;
        const Obj_Entry *defobj;
        Elf_Addr *where, symval;
        Elf32_Addr *where32;
        int r;

        r = -1;
        /*
         * The dynamic loader may be called from a thread, we have
         * limited amounts of stack available so we cannot use alloca().
         */
        if (obj != obj_rtld) {
                cache = calloc(obj->dynsymcount, sizeof(SymCache));
                /* No need to check for NULL here */
        } else
                cache = NULL;

        relalim = (const Elf_Rela *)((caddr_t)obj->rela + obj->relasize);
        for (rela = obj->rela;  rela < relalim;  rela++) {
                /*
                 * First, resolve symbol for relocations which
                 * reference symbols.
                 */
                switch (ELF_R_TYPE(rela->r_info)) {
                case R_X86_64_64:
                case R_X86_64_PC32:
                case R_X86_64_GLOB_DAT:
                case R_X86_64_TPOFF64:
                case R_X86_64_TPOFF32:
                case R_X86_64_DTPMOD64:
                case R_X86_64_DTPOFF64:
                case R_X86_64_DTPOFF32:
                        def = find_symdef(ELF_R_SYM(rela->r_info), obj,
                            &defobj, flags, cache, lockstate);
                        if (def == NULL)
                                goto done;
                        /*
                         * If symbol is IFUNC, only perform relocation
                         * when caller allowed it by passing
                         * SYMLOOK_IFUNC flag.  Skip the relocations
                         * otherwise.
                         *
                         * Also error out in case IFUNC relocations
                         * are specified for TLS, which cannot be
                         * usefully interpreted.
                         */
                        if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
                                switch (ELF_R_TYPE(rela->r_info)) {
                                case R_X86_64_64:
                                case R_X86_64_PC32:
                                case R_X86_64_GLOB_DAT:
                                        if ((flags & SYMLOOK_IFUNC) == 0) {
                                                obj->non_plt_gnu_ifunc = true;
                                                continue;
                                        }
                                        symval = (Elf_Addr)rtld_resolve_ifunc(
                                            defobj, def);
                                        break;
                                case R_X86_64_TPOFF64:
                                case R_X86_64_TPOFF32:
                                case R_X86_64_DTPMOD64:
                                case R_X86_64_DTPOFF64:
                                case R_X86_64_DTPOFF32:
                                        _rtld_error("%s: IFUNC for TLS reloc",
                                            obj->path);
                                        goto done;
                                }
                        } else {
                                if ((flags & SYMLOOK_IFUNC) != 0)
                                        continue;
                                symval = (Elf_Addr)defobj->relocbase +
                                    def->st_value;
                        }
                        break;
                default:
                        if ((flags & SYMLOOK_IFUNC) != 0)
                                continue;
                        break;
                }
                where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
                where32 = (Elf32_Addr *)where;

                switch (ELF_R_TYPE(rela->r_info)) {
                case R_X86_64_NONE:
                        break;
                case R_X86_64_64:
                        *where = symval + rela->r_addend;
                        break;
                case R_X86_64_PC32:
                        /*
                         * I don't think the dynamic linker should
                         * ever see this type of relocation.  But the
                         * binutils-2.6 tools sometimes generate it.
                         */
                        *where32 = (Elf32_Addr)(unsigned long)(symval +
                            rela->r_addend - (Elf_Addr)where);
                        break;
                /* missing: R_X86_64_GOT32 R_X86_64_PLT32 */
                case R_X86_64_COPY:
                        /*
                         * These are deferred until all other relocations have
                         * been done.  All we do here is make sure that the COPY
                         * relocation is not in a shared library.  They are allowed
                         * only in executable files.
                         */
                        if (!obj->mainprog) {
                                _rtld_error("%s: Unexpected R_X86_64_COPY "
                                    "relocation in shared library", obj->path);
                                goto done;
                        }
                        break;
                case R_X86_64_GLOB_DAT:
                        *where = symval;
                        break;
                case R_X86_64_TPOFF64:
                        /*
                         * We lazily allocate offsets for static TLS
                         * as we see the first relocation that
                         * references the TLS block. This allows us to
                         * support (small amounts of) static TLS in
                         * dynamically loaded modules. If we run out
                         * of space, we generate an error.
                         */
                        if (!defobj->tls_static) {
                                if (!allocate_tls_offset((Obj_Entry*) defobj)) {
                                        _rtld_error("%s: No space available "
                                            "for static Thread Local Storage",
                                            obj->path);
                                        goto done;
                                }
                        }
                        *where = (Elf_Addr)(def->st_value - defobj->tlsoffset +
                            rela->r_addend);
                        break;
                case R_X86_64_TPOFF32:
                        /*
                         * We lazily allocate offsets for static TLS
                         * as we see the first relocation that
                         * references the TLS block. This allows us to
                         * support (small amounts of) static TLS in
                         * dynamically loaded modules. If we run out
                         * of space, we generate an error.
                         */
                        if (!defobj->tls_static) {
                                if (!allocate_tls_offset((Obj_Entry*) defobj)) {
                                        _rtld_error("%s: No space available "
                                            "for static Thread Local Storage",
                                            obj->path);
                                        goto done;
                                }
                        }
                        *where32 = (Elf32_Addr)(def->st_value -
                            defobj->tlsoffset + rela->r_addend);
                        break;
                case R_X86_64_DTPMOD64:
                        *where += (Elf_Addr)defobj->tlsindex;
                        break;
                case R_X86_64_DTPOFF64:
                        *where += (Elf_Addr)(def->st_value + rela->r_addend);
                        break;
                case R_X86_64_DTPOFF32:
                        *where32 += (Elf32_Addr)(def->st_value +
                            rela->r_addend);
                        break;
                case R_X86_64_RELATIVE:
                        *where = (Elf_Addr)(obj->relocbase + rela->r_addend);
                        break;
                case R_X86_64_IRELATIVE:
                        obj->irelative_nonplt = true;
                        break;
                /*
                 * missing:
                 * R_X86_64_GOTPCREL, R_X86_64_32, R_X86_64_32S, R_X86_64_16,
                 * R_X86_64_PC16, R_X86_64_8, R_X86_64_PC8
                 */
                default:
                        _rtld_error("%s: Unsupported relocation type %u"
                            " in non-PLT relocations\n", obj->path,
                            (unsigned int)ELF_R_TYPE(rela->r_info));
                        goto done;
                }
        }
        r = 0;
done:
        free(cache);
        return (r);
}

/* Process the PLT relocations. */
int
reloc_plt(Obj_Entry *obj)
{
    const Elf_Rela *relalim;
    const Elf_Rela *rela;

    relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
    for (rela = obj->pltrela;  rela < relalim;  rela++) {
        Elf_Addr *where;

        switch(ELF_R_TYPE(rela->r_info)) {
        case R_X86_64_JMP_SLOT:
          /* Relocate the GOT slot pointing into the PLT. */
          where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
          *where += (Elf_Addr)obj->relocbase;
          break;

        case R_X86_64_IRELATIVE:
          obj->irelative = true;
          break;

        default:
          _rtld_error("Unknown relocation type 0x%02x in PLT (%s)",
                      (unsigned int)ELF_R_TYPE(rela->r_info), obj->path);
          return (-1);
        }
    }
    return 0;
}

/* Relocate the jump slots in an object. */
int
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
    const Elf_Rela *relalim;
    const Elf_Rela *rela;

    if (obj->jmpslots_done)
        return 0;
    relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
    for (rela = obj->pltrela;  rela < relalim;  rela++) {
        Elf_Addr *where, target;
        const Elf_Sym *def;
        const Obj_Entry *defobj;

        switch (ELF_R_TYPE(rela->r_info)) {
        case R_X86_64_JMP_SLOT:
          where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
          def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
                SYMLOOK_IN_PLT | flags, NULL, lockstate);
          if (def == NULL)
              return (-1);
          if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
              obj->gnu_ifunc = true;
              continue;
          }
          target = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend);
          reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela);
          break;

        case R_X86_64_IRELATIVE:
          break;

        default:
          _rtld_error("Unknown relocation type 0x%02x in PLT (%s)",
                      (unsigned int)ELF_R_TYPE(rela->r_info), obj->path);
          return (-1);
        }
    }
    obj->jmpslots_done = true;
    return 0;
}

static void
reloc_iresolve_one(Obj_Entry *obj, const Elf_Rela *rela,
    RtldLockState *lockstate)
{
    Elf_Addr *where, target, *ptr;

    ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend);
    where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
    lock_release(rtld_bind_lock, lockstate);
    target = ((Elf_Addr (*)(void))ptr)();
    wlock_acquire(rtld_bind_lock, lockstate);
    *where = target;
}

int
reloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate)
{
    const Elf_Rela *relalim;
    const Elf_Rela *rela;

    if (!obj->irelative)
        return (0);
    obj->irelative = false;
    relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
    for (rela = obj->pltrela;  rela < relalim;  rela++) {
        switch (ELF_R_TYPE(rela->r_info)) {
        case R_X86_64_JMP_SLOT:
          break;

        case R_X86_64_IRELATIVE:
          reloc_iresolve_one(obj, rela, lockstate);
          break;
        }
    }
    return (0);
}

int
reloc_iresolve_nonplt(Obj_Entry *obj, RtldLockState *lockstate)
{
    const Elf_Rela *relalim;
    const Elf_Rela *rela;

    if (!obj->irelative_nonplt)
        return (0);
    obj->irelative_nonplt = false;
    relalim = (const Elf_Rela *)((char *)obj->rela + obj->relasize);
    for (rela = obj->rela;  rela < relalim;  rela++) {
        if (ELF_R_TYPE(rela->r_info) == R_X86_64_IRELATIVE)
            reloc_iresolve_one(obj, rela, lockstate);
    }
    return (0);
}

int
reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
    const Elf_Rela *relalim;
    const Elf_Rela *rela;

    if (!obj->gnu_ifunc)
        return (0);
    relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
    for (rela = obj->pltrela;  rela < relalim;  rela++) {
        Elf_Addr *where, target;
        const Elf_Sym *def;
        const Obj_Entry *defobj;

        switch (ELF_R_TYPE(rela->r_info)) {
        case R_X86_64_JMP_SLOT:
          where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
          def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
                SYMLOOK_IN_PLT | flags, NULL, lockstate);
          if (def == NULL)
              return (-1);
          if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC)
              continue;
          lock_release(rtld_bind_lock, lockstate);
          target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
          wlock_acquire(rtld_bind_lock, lockstate);
          reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela);
          break;
        }
    }
    obj->gnu_ifunc = false;
    return (0);
}

void *__tls_get_addr(tls_index *ti)
{
    struct tls_tcb *tcb;

    tcb = tls_get_tcb();
    return tls_get_addr_common((Elf_Addr **)&tcb->tcb_dtv, ti->ti_module, ti->ti_offset);
}

void *
__tls_get_addr_tcb(struct tls_tcb *tcb, tls_index *ti)
{
    return tls_get_addr_common((Elf_Addr **)&tcb->tcb_dtv, ti->ti_module, ti->ti_offset);
}