/*-
 * Copyright (c) 1998 Doug Rabson
 * Copyright (c) 2004 Peter Wemm
 * 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 AND CONTRIBUTORS ``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.
 *
 * $FreeBSD: src/sys/kern/link_elf.c,v 1.24 1999/12/24 15:33:36 bde Exp $
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/nlookup.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/linker.h>
#include <machine/elf.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_zone.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>

static int      link_elf_obj_preload_file(const char *, linker_file_t *);
static int      link_elf_obj_preload_finish(linker_file_t);
static int      link_elf_obj_load_file(const char *, linker_file_t *);
static int
link_elf_obj_lookup_symbol(linker_file_t, const char *,
                       c_linker_sym_t *);
static int      link_elf_obj_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t *);
static int
link_elf_obj_search_symbol(linker_file_t, caddr_t value,
                       c_linker_sym_t * sym, long *diffp);

static void     link_elf_obj_unload_file(linker_file_t);
static int
link_elf_obj_lookup_set(linker_file_t, const char *,
                    void ***, void ***, int *);
static void     link_elf_obj_reloc_local(linker_file_t lf);
static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *);

static struct linker_class_ops link_elf_obj_class_ops = {
        link_elf_obj_load_file,
        link_elf_obj_preload_file,
};

static struct linker_file_ops link_elf_obj_file_ops = {
        .lookup_symbol = link_elf_obj_lookup_symbol,
        .symbol_values = link_elf_obj_symbol_values,
        .search_symbol = link_elf_obj_search_symbol,
        .preload_finish = link_elf_obj_preload_finish,
        .unload = link_elf_obj_unload_file,
        .lookup_set = link_elf_obj_lookup_set,
};

typedef struct {
        void           *addr;
        Elf_Off         size;
        int             flags;
        int             sec;            /* Original section */
        char           *name;
}               Elf_progent;

typedef struct {
        Elf_Rel        *rel;
        int             nrel;
        int             sec;
}               Elf_relent;

typedef struct {
        Elf_Rela       *rela;
        int             nrela;
        int             sec;
}               Elf_relaent;


typedef struct elf_file {
        int             preloaded;

        caddr_t         address;        /* Relocation address */
        size_t          bytes;          /* Chunk size in bytes */
        vm_object_t     object;         /* VM object to hold file pages */
        Elf_Shdr       *e_shdr;

        Elf_progent    *progtab;
        int             nprogtab;

        Elf_relaent    *relatab;
        int             nrelatab;

        Elf_relent     *reltab;
        int             nreltab;

        Elf_Sym        *ddbsymtab;      /* The symbol table we are using */
        long            ddbsymcnt;      /* Number of symbols */
        caddr_t         ddbstrtab;      /* String table */
        long            ddbstrcnt;      /* number of bytes in string table */

        caddr_t         shstrtab;       /* Section name string table */
        long            shstrcnt;       /* number of bytes in string table */

        caddr_t         ctftab;         /* CTF table */
        long            ctfcnt;         /* number of bytes in CTF table */
        caddr_t         ctfoff;         /* CTF offset table */
        caddr_t         typoff;         /* Type offset table */
        long            typlen;         /* Number of type entries. */

}              *elf_file_t;

static int      relocate_file(linker_file_t lf);

/*
 * The kernel symbol table starts here.
 */
extern struct _dynamic _DYNAMIC;

static void
link_elf_obj_init(void *arg)
{
#if ELF_TARG_CLASS == ELFCLASS32
        linker_add_class("elf32", NULL, &link_elf_obj_class_ops);
#else
        linker_add_class("elf64", NULL, &link_elf_obj_class_ops);
#endif
}

SYSINIT(link_elf, SI_BOOT2_KLD, SI_ORDER_SECOND, link_elf_obj_init, 0);

static void
link_elf_obj_error(const char *file, const char *s)
{
        kprintf("kldload: %s: %s\n", file, s);
}

static int
link_elf_obj_preload_file(const char *filename, linker_file_t *result)
{
        Elf_Ehdr       *hdr;
        Elf_Shdr       *shdr;
        Elf_Sym *es;
        caddr_t         modptr, baseptr, sizeptr;
        char           *type;
        elf_file_t      ef;
        linker_file_t   lf;
        Elf_Addr        off;
        int             error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;

        /*
         * Look to see if we have the module preloaded.
         */
        modptr = preload_search_by_name(filename);
        if (modptr == NULL)
                return ENOENT;

        /* It's preloaded, check we can handle it and collect information */
        type = (char *)preload_search_info(modptr, MODINFO_TYPE);
        baseptr = preload_search_info(modptr, MODINFO_ADDR);
        sizeptr = preload_search_info(modptr, MODINFO_SIZE);
        hdr = (Elf_Ehdr *) preload_search_info(modptr, MODINFO_METADATA |
                                               MODINFOMD_ELFHDR);
        shdr = (Elf_Shdr *) preload_search_info(modptr, MODINFO_METADATA |
                                                MODINFOMD_SHDR);
        if (type == NULL ||
            (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " obj module") != 0 &&
             strcmp(type, "elf obj module") != 0)) {
                return (EFTYPE);
        }
        if (baseptr == NULL || sizeptr == NULL || hdr == NULL || shdr == NULL)
                return (EINVAL);

        ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
        ef->preloaded = 1;
        ef->address = *(caddr_t *) baseptr;
        ef->bytes = 0;
        lf = linker_make_file(filename, ef, &link_elf_obj_file_ops);
        if (lf == NULL) {
                kfree(ef, M_LINKER);
                return ENOMEM;
        }
        lf->address = ef->address;
        lf->size = *(size_t *) sizeptr;

        if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
            hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
            hdr->e_ident[EI_VERSION] != EV_CURRENT ||
            hdr->e_version != EV_CURRENT ||
            hdr->e_type != ET_REL ||
            hdr->e_machine != ELF_TARG_MACH) {
                error = EFTYPE;
                goto out;
        }
        ef->e_shdr = shdr;

        /* Scan the section header for information and table sizing. */
        symtabindex = -1;
        symstrindex = -1;
        for (i = 0; i < hdr->e_shnum; i++) {
                switch (shdr[i].sh_type) {
                case SHT_PROGBITS:
                case SHT_NOBITS:
                        ef->nprogtab++;
                        break;
                case SHT_SYMTAB:
                        symtabindex = i;
                        symstrindex = shdr[i].sh_link;
                        break;
                case SHT_REL:
                        ef->nreltab++;
                        break;
                case SHT_RELA:
                        ef->nrelatab++;
                        break;
                }
        }

        shstrindex = hdr->e_shstrndx;
        if (ef->nprogtab == 0 || symstrindex < 0 ||
            symstrindex >= hdr->e_shnum ||
            shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
            shstrindex >= hdr->e_shnum ||
            shdr[shstrindex].sh_type != SHT_STRTAB) {
                error = ENOEXEC;
                goto out;
        }
        /* Allocate space for tracking the load chunks */
        if (ef->nprogtab != 0)
                ef->progtab = kmalloc(ef->nprogtab * sizeof(*ef->progtab),
                                     M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nreltab != 0)
                ef->reltab = kmalloc(ef->nreltab * sizeof(*ef->reltab),
                                    M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nrelatab != 0)
                ef->relatab = kmalloc(ef->nrelatab * sizeof(*ef->relatab),
                                     M_LINKER, M_WAITOK | M_ZERO);
        if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
            (ef->nreltab != 0 && ef->reltab == NULL) ||
            (ef->nrelatab != 0 && ef->relatab == NULL)) {
                error = ENOMEM;
                goto out;
        }
        /* XXX, relocate the sh_addr fields saved by the loader. */
        off = 0;
        for (i = 0; i < hdr->e_shnum; i++) {
                if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
                        off = shdr[i].sh_addr;
        }
        for (i = 0; i < hdr->e_shnum; i++) {
                if (shdr[i].sh_addr != 0)
                        shdr[i].sh_addr = shdr[i].sh_addr - off +
                                (Elf_Addr) ef->address;
        }

        ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
        ef->ddbsymtab = (Elf_Sym *) shdr[symtabindex].sh_addr;
        ef->ddbstrcnt = shdr[symstrindex].sh_size;
        ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
        ef->shstrcnt = shdr[shstrindex].sh_size;
        ef->shstrtab = (char *)shdr[shstrindex].sh_addr;

        /* Now fill out progtab and the relocation tables. */
        pb = 0;
        rl = 0;
        ra = 0;
        for (i = 0; i < hdr->e_shnum; i++) {
                switch (shdr[i].sh_type) {
                case SHT_PROGBITS:
                case SHT_NOBITS:
                        ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
                        if (shdr[i].sh_type == SHT_PROGBITS)
                                ef->progtab[pb].name = "<<PROGBITS>>";
                        else
                                ef->progtab[pb].name = "<<NOBITS>>";
                        ef->progtab[pb].size = shdr[i].sh_size;
                        ef->progtab[pb].sec = i;
                        if (ef->shstrtab && shdr[i].sh_name != 0)
                                ef->progtab[pb].name =
                                        ef->shstrtab + shdr[i].sh_name;
#if 0
                        if (ef->progtab[pb].name != NULL &&
                            !strcmp(ef->progtab[pb].name, "set_pcpu")) {
                                void           *dpcpu;

                                dpcpu = dpcpu_alloc(shdr[i].sh_size);
                                if (dpcpu == NULL) {
                                        error = ENOSPC;
                                        goto out;
                                }
                                memcpy(dpcpu, ef->progtab[pb].addr,
                                       ef->progtab[pb].size);
                                dpcpu_copy(dpcpu, shdr[i].sh_size);
                                ef->progtab[pb].addr = dpcpu;
#ifdef VIMAGE
                        } else if (ef->progtab[pb].name != NULL &&
                                   !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
                                void           *vnet_data;

                                vnet_data = vnet_data_alloc(shdr[i].sh_size);
                                if (vnet_data == NULL) {
                                        error = ENOSPC;
                                        goto out;
                                }
                                memcpy(vnet_data, ef->progtab[pb].addr,
                                       ef->progtab[pb].size);
                                vnet_data_copy(vnet_data, shdr[i].sh_size);
                                ef->progtab[pb].addr = vnet_data;
#endif
                        }
#endif
                        /* Update all symbol values with the offset. */
                        for (j = 0; j < ef->ddbsymcnt; j++) {
                                es = &ef->ddbsymtab[j];
                                if (es->st_shndx != i)
                                        continue;
                                es->st_value += (Elf_Addr) ef->progtab[pb].addr;
                        }
                        pb++;
                        break;
                case SHT_REL:
                        ef->reltab[rl].rel = (Elf_Rel *) shdr[i].sh_addr;
                        ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
                        ef->reltab[rl].sec = shdr[i].sh_info;
                        rl++;
                        break;
                case SHT_RELA:
                        ef->relatab[ra].rela = (Elf_Rela *) shdr[i].sh_addr;
                        ef->relatab[ra].nrela =
                                shdr[i].sh_size / sizeof(Elf_Rela);
                        ef->relatab[ra].sec = shdr[i].sh_info;
                        ra++;
                        break;
                }
        }
        if (pb != ef->nprogtab)
                panic("lost progbits");
        if (rl != ef->nreltab)
                panic("lost reltab");
        if (ra != ef->nrelatab)
                panic("lost relatab");

        /* Local intra-module relocations */
        link_elf_obj_reloc_local(lf);

        *result = lf;
        return (0);

out:
        /* preload not done this way */
        linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
        return (error);
}

static int
link_elf_obj_preload_finish(linker_file_t lf)
{
        int error;

        error = relocate_file(lf);

        return (error);
}

static int
link_elf_obj_load_file(const char *filename, linker_file_t * result)
{
        struct nlookupdata nd;
        struct thread  *td = curthread; /* XXX */
        struct proc    *p = td->td_proc;
        char           *pathname;
        struct vnode   *vp;
        Elf_Ehdr       *hdr;
        Elf_Shdr       *shdr;
        Elf_Sym        *es;
        int             nbytes, i, j;
        vm_offset_t     mapbase;
        size_t          mapsize;
        int             error = 0;
        int             resid;
        elf_file_t      ef;
        linker_file_t   lf;
        int             symtabindex;
        int             symstrindex;
        int             shstrindex;
        int             nsym;
        int             pb, rl, ra;
        int             alignmask;

        /* XXX Hack for firmware loading where p == NULL */
        if (p == NULL) {
                p = &proc0;
        }

        KKASSERT(p != NULL);
        if (p->p_ucred == NULL) {
                kprintf("link_elf_obj_load_file: cannot load '%s' from filesystem"
                        " this early\n", filename);
                return ENOENT;
        }
        shdr = NULL;
        lf = NULL;
        mapsize = 0;
        hdr = NULL;
        pathname = linker_search_path(filename);
        if (pathname == NULL)
                return ENOENT;

        error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW | NLC_LOCKVP);
        if (error == 0)
                error = vn_open(&nd, NULL, FREAD, 0);
        kfree(pathname, M_LINKER);
        if (error) {
                nlookup_done(&nd);
                return error;
        }
        vp = nd.nl_open_vp;
        nd.nl_open_vp = NULL;
        nlookup_done(&nd);

        /*
         * Read the elf header from the file.
         */
        hdr = kmalloc(sizeof(*hdr), M_LINKER, M_WAITOK);
        error = vn_rdwr(UIO_READ, vp, (void *)hdr, sizeof(*hdr), 0,
                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
        if (error)
                goto out;
        if (resid != 0) {
                error = ENOEXEC;
                goto out;
        }
        if (!IS_ELF(*hdr)) {
                error = ENOEXEC;
                goto out;
        }

        if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
            || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
                link_elf_obj_error(filename, "Unsupported file layout");
                error = ENOEXEC;
                goto out;
        }
        if (hdr->e_ident[EI_VERSION] != EV_CURRENT
            || hdr->e_version != EV_CURRENT) {
                link_elf_obj_error(filename, "Unsupported file version");
                error = ENOEXEC;
                goto out;
        }
        if (hdr->e_type != ET_REL) {
                error = ENOSYS;
                goto out;
        }
        if (hdr->e_machine != ELF_TARG_MACH) {
                link_elf_obj_error(filename, "Unsupported machine");
                error = ENOEXEC;
                goto out;
        }

        ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
        lf = linker_make_file(filename, ef, &link_elf_obj_file_ops);
        if (lf == NULL) {
                kfree(ef, M_LINKER);
                error = ENOMEM;
                goto out;
        }
        ef->nprogtab = 0;
        ef->e_shdr = NULL;
        ef->nreltab = 0;
        ef->nrelatab = 0;

        /* Allocate and read in the section header */
        nbytes = hdr->e_shnum * hdr->e_shentsize;
        if (nbytes == 0 || hdr->e_shoff == 0 ||
            hdr->e_shentsize != sizeof(Elf_Shdr)) {
                error = ENOEXEC;
                goto out;
        }
        shdr = kmalloc(nbytes, M_LINKER, M_WAITOK);
        ef->e_shdr = shdr;
        error = vn_rdwr(UIO_READ, vp, (caddr_t) shdr, nbytes, hdr->e_shoff,
                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
        if (error)
                goto out;
        if (resid) {
                error = ENOEXEC;
                goto out;
        }
        /* Scan the section header for information and table sizing. */
        nsym = 0;
        symtabindex = -1;
        symstrindex = -1;
        for (i = 0; i < hdr->e_shnum; i++) {
                if (shdr[i].sh_size == 0)
                        continue;
                switch (shdr[i].sh_type) {
                case SHT_PROGBITS:
                case SHT_NOBITS:
                        ef->nprogtab++;
                        break;
                case SHT_SYMTAB:
                        nsym++;
                        symtabindex = i;
                        symstrindex = shdr[i].sh_link;
                        break;
                case SHT_REL:
                        ef->nreltab++;
                        break;
                case SHT_RELA:
                        ef->nrelatab++;
                        break;
                case SHT_STRTAB:
                        break;
                }
        }
        if (ef->nprogtab == 0) {
                link_elf_obj_error(filename, "file has no contents");
                error = ENOEXEC;
                goto out;
        }
        if (nsym != 1) {
                /* Only allow one symbol table for now */
                link_elf_obj_error(filename, "file has no valid symbol table");
                error = ENOEXEC;
                goto out;
        }
        if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
            shdr[symstrindex].sh_type != SHT_STRTAB) {
                link_elf_obj_error(filename, "file has invalid symbol strings");
                error = ENOEXEC;
                goto out;
        }
        /* Allocate space for tracking the load chunks */
        if (ef->nprogtab != 0)
                ef->progtab = kmalloc(ef->nprogtab * sizeof(*ef->progtab),
                                      M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nreltab != 0)
                ef->reltab = kmalloc(ef->nreltab * sizeof(*ef->reltab),
                                     M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nrelatab != 0)
                ef->relatab = kmalloc(ef->nrelatab * sizeof(*ef->relatab),
                                      M_LINKER, M_WAITOK | M_ZERO);
        if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
            (ef->nreltab != 0 && ef->reltab == NULL) ||
            (ef->nrelatab != 0 && ef->relatab == NULL)) {
                error = ENOMEM;
                goto out;
        }
        if (symtabindex == -1)
                panic("lost symbol table index");
        /* Allocate space for and load the symbol table */
        ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
        ef->ddbsymtab = kmalloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
        error = vn_rdwr(UIO_READ, vp, (void *)ef->ddbsymtab,
                        shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
        if (error)
                goto out;
        if (resid != 0) {
                error = EINVAL;
                goto out;
        }
        if (symstrindex == -1)
                panic("lost symbol string index");
        /* Allocate space for and load the symbol strings */
        ef->ddbstrcnt = shdr[symstrindex].sh_size;
        ef->ddbstrtab = kmalloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
        error = vn_rdwr(UIO_READ, vp, ef->ddbstrtab,
                        shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
        if (error)
                goto out;
        if (resid != 0) {
                error = EINVAL;
                goto out;
        }
        /* Do we have a string table for the section names?  */
        shstrindex = -1;
        if (hdr->e_shstrndx != 0 &&
            shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
                shstrindex = hdr->e_shstrndx;
                ef->shstrcnt = shdr[shstrindex].sh_size;
                ef->shstrtab = kmalloc(shdr[shstrindex].sh_size, M_LINKER,
                                       M_WAITOK);
                error = vn_rdwr(UIO_READ, vp, ef->shstrtab,
                                shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
                                UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
                if (error)
                        goto out;
                if (resid != 0) {
                        error = EINVAL;
                        goto out;
                }
        }
        /* Size up code/data(progbits) and bss(nobits). */
        alignmask = 0;
        for (i = 0; i < hdr->e_shnum; i++) {
                if (shdr[i].sh_size == 0)
                        continue;
                switch (shdr[i].sh_type) {
                case SHT_PROGBITS:
                case SHT_NOBITS:
                        alignmask = shdr[i].sh_addralign - 1;
                        mapsize += alignmask;
                        mapsize &= ~alignmask;
                        mapsize += shdr[i].sh_size;
                        break;
                }
        }

        /*
         * We know how much space we need for the text/data/bss/etc. This
         * stuff needs to be in a single chunk so that profiling etc can get
         * the bounds and gdb can associate offsets with modules
         */
        ef->object = vm_object_allocate(OBJT_DEFAULT,
                                        round_page(mapsize) >> PAGE_SHIFT);
        if (ef->object == NULL) {
                error = ENOMEM;
                goto out;
        }
        vm_object_hold(ef->object);
        vm_object_reference_locked(ef->object);
        ef->address = (caddr_t) vm_map_min(kernel_map);
        ef->bytes = 0;

        /*
         * In order to satisfy x86_64's architectural requirements on the
         * location of code and data in the kernel's address space, request a
         * mapping that is above the kernel.
         *
         * vkernel64's text+data is outside the managed VM space entirely.
         */
#if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
        error = vkernel_module_memory_alloc(&mapbase, round_page(mapsize));
        vm_object_drop(ef->object);
#else
        mapbase = KERNBASE;
        error = vm_map_find(kernel_map, ef->object, NULL,
                            0, &mapbase, round_page(mapsize),
                            PAGE_SIZE, TRUE,
                            VM_MAPTYPE_NORMAL, VM_SUBSYS_IMGACT,
                            VM_PROT_ALL, VM_PROT_ALL, 0);
        vm_object_drop(ef->object);
        if (error) {
                vm_object_deallocate(ef->object);
                ef->object = NULL;
                goto out;
        }

        /* Wire the pages */
        error = vm_map_kernel_wiring(kernel_map, mapbase,
                                     mapbase + round_page(mapsize), 0);
#endif
        if (error != KERN_SUCCESS) {
                error = ENOMEM;
                goto out;
        }
        /* Inform the kld system about the situation */
        lf->address = ef->address = (caddr_t) mapbase;
        lf->size = round_page(mapsize);
        ef->bytes = mapsize;

        /*
         * Now load code/data(progbits), zero bss(nobits), allocate space for
         * and load relocs
         */
        pb = 0;
        rl = 0;
        ra = 0;
        alignmask = 0;
        for (i = 0; i < hdr->e_shnum; i++) {
                if (shdr[i].sh_size == 0)
                        continue;
                switch (shdr[i].sh_type) {
                case SHT_PROGBITS:
                case SHT_NOBITS:
                        alignmask = shdr[i].sh_addralign - 1;
                        mapbase += alignmask;
                        mapbase &= ~alignmask;
                        if (ef->shstrtab && shdr[i].sh_name != 0)
                                ef->progtab[pb].name =
                                        ef->shstrtab + shdr[i].sh_name;
                        else if (shdr[i].sh_type == SHT_PROGBITS)
                                ef->progtab[pb].name = "<<PROGBITS>>";
                        else
                                ef->progtab[pb].name = "<<NOBITS>>";
#if 0
                        if (ef->progtab[pb].name != NULL &&
                            !strcmp(ef->progtab[pb].name, "set_pcpu"))
                                ef->progtab[pb].addr =
                                        dpcpu_alloc(shdr[i].sh_size);
#ifdef VIMAGE
                        else if (ef->progtab[pb].name != NULL &&
                                 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
                                ef->progtab[pb].addr =
                                        vnet_data_alloc(shdr[i].sh_size);
#endif
                        else
#endif
                                ef->progtab[pb].addr =
                                        (void *)(uintptr_t) mapbase;
                        if (ef->progtab[pb].addr == NULL) {
                                error = ENOSPC;
                                goto out;
                        }
                        ef->progtab[pb].size = shdr[i].sh_size;
                        ef->progtab[pb].sec = i;
                        if (shdr[i].sh_type == SHT_PROGBITS) {
                                error = vn_rdwr(UIO_READ, vp,
                                                ef->progtab[pb].addr,
                                                shdr[i].sh_size, shdr[i].sh_offset,
                                                UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
                                                &resid);
                                if (error)
                                        goto out;
                                if (resid != 0) {
                                        error = EINVAL;
                                        goto out;
                                }
#if 0
                                /* Initialize the per-cpu or vnet area. */
                                if (ef->progtab[pb].addr != (void *)mapbase &&
                                    !strcmp(ef->progtab[pb].name, "set_pcpu"))
                                        dpcpu_copy(ef->progtab[pb].addr,
                                                   shdr[i].sh_size);
#ifdef VIMAGE
                                else if (ef->progtab[pb].addr !=
                                         (void *)mapbase &&
                                         !strcmp(ef->progtab[pb].name, VNET_SETNAME))
                                        vnet_data_copy(ef->progtab[pb].addr,
                                                       shdr[i].sh_size);
#endif
#endif
                        } else
                                bzero(ef->progtab[pb].addr, shdr[i].sh_size);

                        /* Update all symbol values with the offset. */
                        for (j = 0; j < ef->ddbsymcnt; j++) {
                                es = &ef->ddbsymtab[j];
                                if (es->st_shndx != i)
                                        continue;
                                es->st_value += (Elf_Addr) ef->progtab[pb].addr;
                        }
                        mapbase += shdr[i].sh_size;
                        pb++;
                        break;
                case SHT_REL:
                        ef->reltab[rl].rel = kmalloc(shdr[i].sh_size, M_LINKER, M_WAITOK);
                        ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
                        ef->reltab[rl].sec = shdr[i].sh_info;
                        error = vn_rdwr(UIO_READ, vp,
                                        (void *)ef->reltab[rl].rel,
                                        shdr[i].sh_size, shdr[i].sh_offset,
                                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
                        if (error)
                                goto out;
                        if (resid != 0) {
                                error = EINVAL;
                                goto out;
                        }
                        rl++;
                        break;
                case SHT_RELA:
                        ef->relatab[ra].rela = kmalloc(shdr[i].sh_size, M_LINKER, M_WAITOK);
                        ef->relatab[ra].nrela = shdr[i].sh_size / sizeof(Elf_Rela);
                        ef->relatab[ra].sec = shdr[i].sh_info;
                        error = vn_rdwr(UIO_READ, vp,
                                        (void *)ef->relatab[ra].rela,
                                        shdr[i].sh_size, shdr[i].sh_offset,
                                        UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
                        if (error)
                                goto out;
                        if (resid != 0) {
                                error = EINVAL;
                                goto out;
                        }
                        ra++;
                        break;
                }
        }
        if (pb != ef->nprogtab)
                panic("lost progbits");
        if (rl != ef->nreltab)
                panic("lost reltab");
        if (ra != ef->nrelatab)
                panic("lost relatab");
        if (mapbase != (vm_offset_t) ef->address + mapsize)
                panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)",
                      mapbase, ef->address, mapsize,
                      (vm_offset_t) ef->address + mapsize);

        /* Local intra-module relocations */
        link_elf_obj_reloc_local(lf);

        /* Pull in dependencies */
        error = linker_load_dependencies(lf);
        if (error)
                goto out;

        /* External relocations */
        error = relocate_file(lf);
        if (error)
                goto out;

        *result = lf;

out:
        if (error && lf)
                linker_file_unload(lf /*, LINKER_UNLOAD_FORCE */);
        if (hdr)
                kfree(hdr, M_LINKER);
        vn_unlock(vp);
        vn_close(vp, FREAD, NULL);

        return error;
}

static void
link_elf_obj_unload_file(linker_file_t file)
{
        elf_file_t      ef = file->priv;
        int i;

        if (ef->progtab) {
                for (i = 0; i < ef->nprogtab; i++) {
                        if (ef->progtab[i].size == 0)
                                continue;
                        if (ef->progtab[i].name == NULL)
                                continue;
#if 0
                        if (!strcmp(ef->progtab[i].name, "set_pcpu"))
                                dpcpu_free(ef->progtab[i].addr,
                                    ef->progtab[i].size);
#ifdef VIMAGE
                        else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
                                vnet_data_free(ef->progtab[i].addr,
                                    ef->progtab[i].size);
#endif
#endif
                }
        }
        if (ef->preloaded) {
                if (ef->reltab)
                        kfree(ef->reltab, M_LINKER);
                if (ef->relatab)
                        kfree(ef->relatab, M_LINKER);
                if (ef->progtab)
                        kfree(ef->progtab, M_LINKER);
                if (ef->ctftab)
                        kfree(ef->ctftab, M_LINKER);
                if (ef->ctfoff)
                        kfree(ef->ctfoff, M_LINKER);
                if (ef->typoff)
                        kfree(ef->typoff, M_LINKER);
                if (file->pathname != NULL)
                        preload_delete_name(file->pathname);
                kfree(ef, M_LINKER);
                /* XXX reclaim module memory? */
                return;
        }

        for (i = 0; i < ef->nreltab; i++)
                if (ef->reltab[i].rel)
                        kfree(ef->reltab[i].rel, M_LINKER);
        for (i = 0; i < ef->nrelatab; i++)
                if (ef->relatab[i].rela)
                        kfree(ef->relatab[i].rela, M_LINKER);
        if (ef->reltab)
                kfree(ef->reltab, M_LINKER);
        if (ef->relatab)
                kfree(ef->relatab, M_LINKER);
        if (ef->progtab)
                kfree(ef->progtab, M_LINKER);

        if (ef->object) {
#if defined(__x86_64__) && defined(_KERNEL_VIRTUAL)
                vkernel_module_memory_free((vm_offset_t)ef->address, ef->bytes);
#else
                vm_map_remove(kernel_map, (vm_offset_t) ef->address,
                    (vm_offset_t) ef->address +
                    (ef->object->size << PAGE_SHIFT));
#endif
                vm_object_deallocate(ef->object);
                ef->object = NULL;
        }
        if (ef->e_shdr)
                kfree(ef->e_shdr, M_LINKER);
        if (ef->ddbsymtab)
                kfree(ef->ddbsymtab, M_LINKER);
        if (ef->ddbstrtab)
                kfree(ef->ddbstrtab, M_LINKER);
        if (ef->shstrtab)
                kfree(ef->shstrtab, M_LINKER);
        if (ef->ctftab)
                kfree(ef->ctftab, M_LINKER);
        if (ef->ctfoff)
                kfree(ef->ctfoff, M_LINKER);
        if (ef->typoff)
                kfree(ef->typoff, M_LINKER);
        kfree(ef, M_LINKER);
}

static const char *
symbol_name(elf_file_t ef, Elf_Size r_info)
{
        const Elf_Sym  *ref;

        if (ELF_R_SYM(r_info)) {
                ref = ef->ddbsymtab + ELF_R_SYM(r_info);
                return ef->ddbstrtab + ref->st_name;
        } else
                return NULL;
}

static Elf_Addr
findbase(elf_file_t ef, int sec)
{
        int i;
        Elf_Addr base = 0;

        for (i = 0; i < ef->nprogtab; i++) {
                if (sec == ef->progtab[i].sec) {
                        base = (Elf_Addr)ef->progtab[i].addr;
                        break;
                }
        }
        return base;
}

static int
relocate_file(linker_file_t lf)
{
        elf_file_t      ef = lf->priv;
        const Elf_Rel *rellim;
        const Elf_Rel *rel;
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        const char *symname;
        const Elf_Sym *sym;
        int i;
        Elf_Size symidx;
        Elf_Addr base;

        /* Perform relocations without addend if there are any: */
        for (i = 0; i < ef->nreltab; i++) {
                rel = ef->reltab[i].rel;
                if (rel == NULL)
                        panic("lost a reltab!");
                rellim = rel + ef->reltab[i].nrel;
                base = findbase(ef, ef->reltab[i].sec);
                if (base == 0)
                        panic("lost base for reltab");
                for ( ; rel < rellim; rel++) {
                        symidx = ELF_R_SYM(rel->r_info);
                        if (symidx >= ef->ddbsymcnt)
                                continue;
                        sym = ef->ddbsymtab + symidx;
                        /* Local relocs are already done */
                        if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
                                continue;
                        if (elf_reloc(lf, base, rel, ELF_RELOC_REL,
                            elf_obj_lookup)) {
                                symname = symbol_name(ef, rel->r_info);
                                kprintf("link_elf_obj_obj: symbol %s undefined\n",
                                    symname);
                                return ENOENT;
                        }
                }
        }

        /* Perform relocations with addend if there are any: */
        for (i = 0; i < ef->nrelatab; i++) {
                rela = ef->relatab[i].rela;
                if (rela == NULL)
                        panic("lost a relatab!");
                relalim = rela + ef->relatab[i].nrela;
                base = findbase(ef, ef->relatab[i].sec);
                if (base == 0)
                        panic("lost base for relatab");
                for ( ; rela < relalim; rela++) {
                        symidx = ELF_R_SYM(rela->r_info);
                        if (symidx >= ef->ddbsymcnt)
                                continue;
                        sym = ef->ddbsymtab + symidx;
                        /* Local relocs are already done */
                        if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
                                continue;
                        if (elf_reloc(lf, base, rela, ELF_RELOC_RELA,
                            elf_obj_lookup)) {
                                symname = symbol_name(ef, rela->r_info);
                                kprintf("link_elf_obj_obj: symbol %s undefined\n",
                                    symname);
                                return ENOENT;
                        }
                }
        }

        return 0;
}

static int
link_elf_obj_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
{
        elf_file_t ef = lf->priv;
        const Elf_Sym *symp;
        const char *strp;
        int i;

        for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
                strp = ef->ddbstrtab + symp->st_name;
                if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
                        *sym = (c_linker_sym_t) symp;
                        return 0;
                }
        }
        return ENOENT;
}

static int
link_elf_obj_symbol_values(linker_file_t lf, c_linker_sym_t sym,
    linker_symval_t *symval)
{
        elf_file_t ef = lf->priv;
        const Elf_Sym *es = (const Elf_Sym*) sym;

        if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
                symval->name = ef->ddbstrtab + es->st_name;
                symval->value = (caddr_t)es->st_value;
                symval->size = es->st_size;
                return 0;
        }
        return ENOENT;
}

static int
link_elf_obj_search_symbol(linker_file_t lf, caddr_t value,
    c_linker_sym_t *sym, long *diffp)
{
        elf_file_t ef = lf->priv;
        u_long off = (uintptr_t) (void *) value;
        u_long diff = off;
        u_long st_value;
        const Elf_Sym *es;
        const Elf_Sym *best = NULL;
        int i;

        for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
                if (es->st_name == 0)
                        continue;
                st_value = es->st_value;
                if (off >= st_value) {
                        if (off - st_value < diff) {
                                diff = off - st_value;
                                best = es;
                                if (diff == 0)
                                        break;
                        } else if (off - st_value == diff) {
                                best = es;
                        }
                }
        }
        if (best == NULL)
                *diffp = off;
        else
                *diffp = diff;
        *sym = (c_linker_sym_t) best;

        return 0;
}

/*
 * Look up a linker set on an ELF system.
 */
static int
link_elf_obj_lookup_set(linker_file_t lf, const char *name,
    void ***startp, void ***stopp, int *countp)
{
        elf_file_t ef = lf->priv;
        void **start, **stop;
        int i, count;

        /* Relative to section number */
        for (i = 0; i < ef->nprogtab; i++) {
                if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
                    strcmp(ef->progtab[i].name + 4, name) == 0) {
                        start  = (void **)ef->progtab[i].addr;
                        stop = (void **)((char *)ef->progtab[i].addr +
                            ef->progtab[i].size);
                        count = stop - start;
                        if (startp)
                                *startp = start;
                        if (stopp)
                                *stopp = stop;
                        if (countp)
                                *countp = count;
                        return (0);
                }
        }
        return (ESRCH);
}

/*
 * Symbol lookup function that can be used when the symbol index is known (ie
 * in relocations). It uses the symbol index instead of doing a fully fledged
 * hash table based lookup when such is valid. For example for local symbols.
 * This is not only more efficient, it's also more correct. It's not always
 * the case that the symbol can be found through the hash table.
 */
static int
elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *result)
{
        elf_file_t ef = lf->priv;
        const Elf_Sym *sym;
        const char *symbol;

        /* Don't even try to lookup the symbol if the index is bogus. */
        if (symidx >= ef->ddbsymcnt)
                return (ENOENT);

        sym = ef->ddbsymtab + symidx;

        /* Quick answer if there is a definition included. */
        if (sym->st_shndx != SHN_UNDEF) {
                *result = sym->st_value;
                return (0);
        }

        /* If we get here, then it is undefined and needs a lookup. */
        switch (ELF_ST_BIND(sym->st_info)) {
        case STB_LOCAL:
                /* Local, but undefined? huh? */
                return (ENOENT);

        case STB_GLOBAL:
                /* Relative to Data or Function name */
                symbol = ef->ddbstrtab + sym->st_name;

                /* Force a lookup failure if the symbol name is bogus. */
                if (*symbol == 0)
                        return (ENOENT);
                return (linker_file_lookup_symbol(lf, symbol, deps, (caddr_t *)result));

        case STB_WEAK:
                kprintf("link_elf_obj_obj: Weak symbols not supported\n");
                return (ENOENT);

        default:
                return (ENOENT);
        }
}

static void
link_elf_obj_fix_link_set(elf_file_t ef)
{
        static const char startn[] = "__start_";
        static const char stopn[] = "__stop_";
        Elf_Sym *sym;
        const char *sym_name, *linkset_name;
        Elf_Addr startp, stopp;
        Elf_Size symidx;
        int start, i;

        startp = stopp = 0;
        for (symidx = 1 /* zero entry is special */;
                symidx < ef->ddbsymcnt; symidx++) {
                sym = ef->ddbsymtab + symidx;
                if (sym->st_shndx != SHN_UNDEF)
                        continue;

                sym_name = ef->ddbstrtab + sym->st_name;
                if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
                        start = 1;
                        linkset_name = sym_name + sizeof(startn) - 1;
                }
                else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
                        start = 0;
                        linkset_name = sym_name + sizeof(stopn) - 1;
                }
                else
                        continue;

                for (i = 0; i < ef->nprogtab; i++) {
                        if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
                                startp = (Elf_Addr)ef->progtab[i].addr;
                                stopp = (Elf_Addr)(startp + ef->progtab[i].size);
                                break;
                        }
                }
                if (i == ef->nprogtab)
                        continue;

                sym->st_value = start ? startp : stopp;
                sym->st_shndx = i;
        }
}

static void
link_elf_obj_reloc_local(linker_file_t lf)
{
        elf_file_t ef = lf->priv;
        const Elf_Rel *rellim;
        const Elf_Rel *rel;
        const Elf_Rela *relalim;
        const Elf_Rela *rela;
        const Elf_Sym *sym;
        Elf_Addr base;
        int i;
        Elf_Size symidx;

        link_elf_obj_fix_link_set(ef);

        /* Perform relocations without addend if there are any: */
        for (i = 0; i < ef->nreltab; i++) {
                rel = ef->reltab[i].rel;
                if (rel == NULL)
                        panic("lost a reltab!");
                rellim = rel + ef->reltab[i].nrel;
                base = findbase(ef, ef->reltab[i].sec);
                if (base == 0)
                        panic("lost base for reltab");
                for ( ; rel < rellim; rel++) {
                        symidx = ELF_R_SYM(rel->r_info);
                        if (symidx >= ef->ddbsymcnt)
                                continue;
                        sym = ef->ddbsymtab + symidx;
                        /* Only do local relocs */
                        if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
                                continue;
                        elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
                            elf_obj_lookup);
                }
        }

        /* Perform relocations with addend if there are any: */
        for (i = 0; i < ef->nrelatab; i++) {
                rela = ef->relatab[i].rela;
                if (rela == NULL)
                        panic("lost a relatab!");
                relalim = rela + ef->relatab[i].nrela;
                base = findbase(ef, ef->relatab[i].sec);
                if (base == 0)
                        panic("lost base for relatab");
                for ( ; rela < relalim; rela++) {
                        symidx = ELF_R_SYM(rela->r_info);
                        if (symidx >= ef->ddbsymcnt)
                                continue;
                        sym = ef->ddbsymtab + symidx;
                        /* Only do local relocs */
                        if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
                                continue;
                        elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
                            elf_obj_lookup);
                }
        }
}