/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1998-2000 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.
 */

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/linker.h>
#include <sys/mutex.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>

#include <machine/elf.h>

#include <net/vnet.h>

#include <security/mac/mac_framework.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>

#include <sys/link_elf.h>

#ifdef DDB_CTF
#include <contrib/zlib/zlib.h>
#endif

#include "linker_if.h"

typedef struct {
        void            *addr;
        void            *origaddr; /* Used by debuggers. */
        Elf_Off         size;
        int             flags;  /* Section flags. */
        int             sec;    /* Original section number. */
        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 {
        struct linker_file lf;          /* Common fields */

        int             preloaded;
        caddr_t         address;        /* Relocation address */
        vm_object_t     object;         /* VM object to hold file pages */
        Elf_Shdr        *e_shdr;

        Elf_progent     *progtab;
        u_int           nprogtab;

        Elf_relaent     *relatab;
        u_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;

#include <kern/kern_ctf.c>

static int      link_elf_link_preload(linker_class_t cls,
                    const char *, linker_file_t *);
static int      link_elf_link_preload_finish(linker_file_t);
static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
static int      link_elf_lookup_symbol(linker_file_t, const char *,
                    c_linker_sym_t *);
static int      link_elf_lookup_debug_symbol(linker_file_t, const char *,
                    c_linker_sym_t *);
static int      link_elf_lookup_debug_symbol_ctf(linker_file_t lf,
                    const char *name, c_linker_sym_t *sym, linker_ctf_t *lc);
static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
                    linker_symval_t *);
static int      link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
                    linker_symval_t *);
static int      link_elf_search_symbol(linker_file_t, caddr_t value,
                    c_linker_sym_t *sym, long *diffp);

static void     link_elf_unload_file(linker_file_t);
static int      link_elf_lookup_set(linker_file_t, const char *,
                    void ***, void ***, int *);
static int      link_elf_each_function_name(linker_file_t,
                    int (*)(const char *, void *), void *);
static int      link_elf_each_function_nameval(linker_file_t,
                                linker_function_nameval_callback_t,
                                void *);
static int      link_elf_reloc_local(linker_file_t, bool);
static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
static long     link_elf_strtab_get(linker_file_t, caddr_t *);
#ifdef VIMAGE
static void     link_elf_propagate_vnets(linker_file_t);
#endif

static int      elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
                    Elf_Addr *);

static kobj_method_t link_elf_methods[] = {
        KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
        KOBJMETHOD(linker_lookup_debug_symbol,  link_elf_lookup_debug_symbol),
        KOBJMETHOD(linker_lookup_debug_symbol_ctf, link_elf_lookup_debug_symbol_ctf),
        KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
        KOBJMETHOD(linker_debug_symbol_values,  link_elf_debug_symbol_values),
        KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
        KOBJMETHOD(linker_unload,               link_elf_unload_file),
        KOBJMETHOD(linker_load_file,            link_elf_load_file),
        KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
        KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
        KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
        KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
        KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
        KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
        KOBJMETHOD(linker_ctf_lookup_typename,  link_elf_ctf_lookup_typename),
        KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
        KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
#ifdef VIMAGE
        KOBJMETHOD(linker_propagate_vnets,      link_elf_propagate_vnets),
#endif
        KOBJMETHOD_END
};

static struct linker_class link_elf_class = {
#if ELF_TARG_CLASS == ELFCLASS32
        "elf32_obj",
#else
        "elf64_obj",
#endif
        link_elf_methods, sizeof(struct elf_file)
};

static bool link_elf_obj_leak_locals = true;
SYSCTL_BOOL(_debug, OID_AUTO, link_elf_obj_leak_locals,
    CTLFLAG_RWTUN, &link_elf_obj_leak_locals, 0,
    "Allow local symbols to participate in global module symbol resolution");

static int      relocate_file(elf_file_t ef);
static void     elf_obj_cleanup_globals_cache(elf_file_t);

static void
link_elf_error(const char *filename, const char *s)
{
        if (filename == NULL)
                printf("kldload: %s\n", s);
        else
                printf("kldload: %s: %s\n", filename, s);
}

static void
link_elf_init(void *arg)
{

        linker_add_class(&link_elf_class);
}
SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);

static void
link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end,
    vm_prot_t prot)
{
        int error __unused;

        KASSERT(start <= end && start >= (vm_offset_t)ef->address &&
            end <= round_page((vm_offset_t)ef->address + ef->lf.size),
            ("link_elf_protect_range: invalid range %#jx-%#jx",
            (uintmax_t)start, (uintmax_t)end));

        if (start == end)
                return;
        if (ef->preloaded) {
#ifdef __amd64__
                error = pmap_change_prot(start, end - start, prot);
                KASSERT(error == 0,
                    ("link_elf_protect_range: pmap_change_prot() returned %d",
                    error));
#endif
                return;
        }
        error = vm_map_protect(kernel_map, start, end, prot, 0,
            VM_MAP_PROTECT_SET_PROT);
        KASSERT(error == KERN_SUCCESS,
            ("link_elf_protect_range: vm_map_protect() returned %d", error));
}

/*
 * Restrict permissions on linker file memory based on section flags.
 * Sections need not be page-aligned, so overlap within a page is possible.
 */
static void
link_elf_protect(elf_file_t ef)
{
        vm_offset_t end, segend, segstart, start;
        vm_prot_t gapprot, prot, segprot;
        int i;

        /*
         * If the file was preloaded, the last page may contain other preloaded
         * data which may need to be writeable.  ELF files are always
         * page-aligned, but other preloaded data, such as entropy or CPU
         * microcode may be loaded with a smaller alignment.
         */
        gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ;

        start = end = (vm_offset_t)ef->address;
        prot = VM_PROT_READ;
        for (i = 0; i < ef->nprogtab; i++) {
                /*
                 * VNET and DPCPU sections have their memory allocated by their
                 * respective subsystems.
                 */
                if (ef->progtab[i].name != NULL && (
#ifdef VIMAGE
                    strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 ||
#endif
                    strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0))
                        continue;

                segstart = trunc_page((vm_offset_t)ef->progtab[i].addr);
                segend = round_page((vm_offset_t)ef->progtab[i].addr +
                    ef->progtab[i].size);
                segprot = VM_PROT_READ;
                if ((ef->progtab[i].flags & SHF_WRITE) != 0)
                        segprot |= VM_PROT_WRITE;
                if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0)
                        segprot |= VM_PROT_EXECUTE;

                if (end <= segstart) {
                        /*
                         * Case 1: there is no overlap between the previous
                         * segment and this one.  Apply protections to the
                         * previous segment, and protect the gap between the
                         * previous and current segments, if any.
                         */
                        link_elf_protect_range(ef, start, end, prot);
                        link_elf_protect_range(ef, end, segstart, gapprot);

                        start = segstart;
                        end = segend;
                        prot = segprot;
                } else if (start < segstart && end == segend) {
                        /*
                         * Case 2: the current segment is a subrange of the
                         * previous segment.  Apply protections to the
                         * non-overlapping portion of the previous segment.
                         */
                        link_elf_protect_range(ef, start, segstart, prot);

                        start = segstart;
                        prot |= segprot;
                } else if (end < segend) {
                        /*
                         * Case 3: there is partial overlap between the previous
                         * and current segments.  Apply protections to the
                         * non-overlapping portion of the previous segment, and
                         * then the overlap, which must use the union of the two
                         * segments' protections.
                         */
                        link_elf_protect_range(ef, start, segstart, prot);
                        link_elf_protect_range(ef, segstart, end,
                            prot | segprot);
                        start = end;
                        end = segend;
                        prot = segprot;
                } else {
                        /*
                         * Case 4: the two segments reside in the same page.
                         */
                        prot |= segprot;
                }
        }

        /*
         * Fix up the last unprotected segment and trailing data.
         */
        link_elf_protect_range(ef, start, end, prot);
        link_elf_protect_range(ef, end,
            round_page((vm_offset_t)ef->address + ef->lf.size), gapprot);
}

static int
link_elf_link_preload(linker_class_t cls, const char *filename,
    linker_file_t *result)
{
        Elf_Ehdr *hdr;
        Elf_Shdr *shdr;
        Elf_Sym *es;
        void *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 file preloaded */
        modptr = preload_search_by_name(filename);
        if (modptr == NULL)
                return ENOENT;

        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, preload_modtype_obj) != 0)
                return (EFTYPE);
        if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
            shdr == NULL)
                return (EINVAL);

        lf = linker_make_file(filename, &link_elf_class);
        if (lf == NULL)
                return (ENOMEM);

        ef = (elf_file_t)lf;
        ef->preloaded = 1;
        ef->address = *(caddr_t *)baseptr;
        lf->address = *(caddr_t *)baseptr;
        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:
#ifdef __amd64__
                case SHT_X86_64_UNWIND:
#endif
                case SHT_INIT_ARRAY:
                case SHT_FINI_ARRAY:
                        /* Ignore sections not loaded by the loader. */
                        if (shdr[i].sh_addr == 0)
                                break;
                        ef->nprogtab++;
                        break;
                case SHT_SYMTAB:
                        symtabindex = i;
                        symstrindex = shdr[i].sh_link;
                        break;
                case SHT_REL:
                        /*
                         * Ignore relocation tables for sections not
                         * loaded by the loader.
                         */
                        if (shdr[shdr[i].sh_info].sh_addr == 0)
                                break;
                        ef->nreltab++;
                        break;
                case SHT_RELA:
                        if (shdr[shdr[i].sh_info].sh_addr == 0)
                                break;
                        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) {
                printf("%s: bad/missing section headers\n", filename);
                error = ENOEXEC;
                goto out;
        }

        /* Allocate space for tracking the load chunks */
        if (ef->nprogtab != 0)
                ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
                    M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nreltab != 0)
                ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
                    M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nrelatab != 0)
                ef->relatab = malloc(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:
#ifdef __amd64__
                case SHT_X86_64_UNWIND:
#endif
                case SHT_INIT_ARRAY:
                case SHT_FINI_ARRAY:
                        if (shdr[i].sh_addr == 0)
                                break;
                        ef->progtab[pb].addr = ef->progtab[pb].origaddr =
                            (void *)shdr[i].sh_addr;
                        if (shdr[i].sh_type == SHT_PROGBITS)
                                ef->progtab[pb].name = "<<PROGBITS>>";
#ifdef __amd64__
                        else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
                                ef->progtab[pb].name = "<<UNWIND>>";
#endif
                        else if (shdr[i].sh_type == SHT_INIT_ARRAY)
                                ef->progtab[pb].name = "<<INIT_ARRAY>>";
                        else if (shdr[i].sh_type == SHT_FINI_ARRAY)
                                ef->progtab[pb].name = "<<FINI_ARRAY>>";
                        else
                                ef->progtab[pb].name = "<<NOBITS>>";
                        ef->progtab[pb].size = shdr[i].sh_size;
                        ef->progtab[pb].flags = shdr[i].sh_flags;
                        ef->progtab[pb].sec = i;
                        if (ef->shstrtab && shdr[i].sh_name != 0)
                                ef->progtab[pb].name =
                                    ef->shstrtab + shdr[i].sh_name;
                        if (ef->progtab[pb].name != NULL && 
                            !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
                                void *dpcpu;

                                dpcpu = dpcpu_alloc(shdr[i].sh_size);
                                if (dpcpu == NULL) {
                                        printf("%s: pcpu module space is out "
                                            "of space; cannot allocate %#jx "
                                            "for %s\n", __func__,
                                            (uintmax_t)shdr[i].sh_size,
                                            filename);
                                        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) {
                                        printf("%s: vnet module space is out "
                                            "of space; cannot allocate %#jx "
                                            "for %s\n", __func__,
                                            (uintmax_t)shdr[i].sh_size,
                                            filename);
                                        error = ENOSPC;
                                        goto out;
                                }
                                memcpy(vnet_data, ef->progtab[pb].addr,
                                    ef->progtab[pb].size);
                                ef->progtab[pb].addr = vnet_data;
                                vnet_save_init(ef->progtab[pb].addr,
                                    ef->progtab[pb].size);
#endif
                        } else if ((ef->progtab[pb].name != NULL &&
                            strcmp(ef->progtab[pb].name, ".ctors") == 0) ||
                            shdr[i].sh_type == SHT_INIT_ARRAY) {
                                if (lf->ctors_addr != 0) {
                                        printf(
                                    "%s: multiple ctor sections in %s\n",
                                            __func__, filename);
                                } else {
                                        lf->ctors_addr = ef->progtab[pb].addr;
                                        lf->ctors_size = shdr[i].sh_size;
                                }
                        } else if ((ef->progtab[pb].name != NULL &&
                            strcmp(ef->progtab[pb].name, ".dtors") == 0) ||
                            shdr[i].sh_type == SHT_FINI_ARRAY) {
                                if (lf->dtors_addr != 0) {
                                        printf(
                                    "%s: multiple dtor sections in %s\n",
                                            __func__, filename);
                                } else {
                                        lf->dtors_addr = ef->progtab[pb].addr;
                                        lf->dtors_size = 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;
                        }
                        pb++;
                        break;
                case SHT_REL:
                        if (shdr[shdr[i].sh_info].sh_addr == 0)
                                break;
                        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:
                        if (shdr[shdr[i].sh_info].sh_addr == 0)
                                break;
                        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) {
                printf("%s: lost progbits\n", filename);
                error = ENOEXEC;
                goto out;
        }
        if (rl != ef->nreltab) {
                printf("%s: lost reltab\n", filename);
                error = ENOEXEC;
                goto out;
        }
        if (ra != ef->nrelatab) {
                printf("%s: lost relatab\n", filename);
                error = ENOEXEC;
                goto out;
        }

        /*
         * The file needs to be writeable and executable while applying
         * relocations.  Mapping protections are applied once relocation
         * processing is complete.
         */
        link_elf_protect_range(ef, (vm_offset_t)ef->address,
            round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL);

        /* Local intra-module relocations */
        error = link_elf_reloc_local(lf, false);
        if (error != 0)
                goto out;
        *result = lf;
        return (0);

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

static void
link_elf_invoke_cbs(caddr_t addr, size_t size)
{
        void (**ctor)(void);
        size_t i, cnt;

        if (addr == NULL || size == 0)
                return;
        cnt = size / sizeof(*ctor);
        ctor = (void *)addr;
        for (i = 0; i < cnt; i++) {
                if (ctor[i] != NULL)
                        (*ctor[i])();
        }
}

static void
link_elf_invoke_ctors(linker_file_t lf)
{
        KASSERT(lf->ctors_invoked == LF_NONE,
            ("%s: file %s ctor state %d",
            __func__, lf->filename, lf->ctors_invoked));

        link_elf_invoke_cbs(lf->ctors_addr, lf->ctors_size);
        lf->ctors_invoked = LF_CTORS;
}

static void
link_elf_invoke_dtors(linker_file_t lf)
{
        KASSERT(lf->ctors_invoked != LF_DTORS,
            ("%s: file %s ctor state %d",
            __func__, lf->filename, lf->ctors_invoked));

        if (lf->ctors_invoked == LF_CTORS) {
                link_elf_invoke_cbs(lf->dtors_addr, lf->dtors_size);
                lf->ctors_invoked = LF_DTORS;
        }
}

static int
link_elf_link_preload_finish(linker_file_t lf)
{
        elf_file_t ef;
        int error;

        ef = (elf_file_t)lf;
        error = relocate_file(ef);
        if (error)
                return (error);

        /* Notify MD code that a module is being loaded. */
        error = elf_cpu_load_file(lf);
        if (error)
                return (error);

#if defined(__i386__) || defined(__amd64__)
        /* Now ifuncs. */
        error = link_elf_reloc_local(lf, true);
        if (error != 0)
                return (error);
#endif

        /* Apply protections now that relocation processing is complete. */
        link_elf_protect(ef);

        link_elf_invoke_ctors(lf);
        return (0);
}

static int
link_elf_load_file(linker_class_t cls, const char *filename,
    linker_file_t *result)
{
        struct nameidata *nd;
        struct thread *td = curthread;  /* XXX */
        Elf_Ehdr *hdr;
        Elf_Shdr *shdr;
        Elf_Sym *es;
        int nbytes, i, j;
        vm_offset_t mapbase;
        size_t mapsize;
        int error = 0;
        ssize_t resid;
        int flags;
        elf_file_t ef;
        linker_file_t lf;
        int symtabindex;
        int symstrindex;
        int shstrindex;
        int nsym;
        int pb, rl, ra;
        int alignmask;

        shdr = NULL;
        lf = NULL;
        mapsize = 0;
        hdr = NULL;

        nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
        NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
        flags = FREAD;
        error = vn_open(nd, &flags, 0, NULL);
        if (error) {
                free(nd, M_TEMP);
                return error;
        }
        NDFREE_PNBUF(nd);
        if (nd->ni_vp->v_type != VREG) {
                error = ENOEXEC;
                goto out;
        }
#ifdef MAC
        error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
        if (error) {
                goto out;
        }
#endif

        /* Read the elf header from the file. */
        hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
        error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
            UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
            &resid, td);
        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_error(filename, "Unsupported file layout");
                error = ENOEXEC;
                goto out;
        }
        if (hdr->e_ident[EI_VERSION] != EV_CURRENT
            || hdr->e_version != EV_CURRENT) {
                link_elf_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_error(filename, "Unsupported machine");
                error = ENOEXEC;
                goto out;
        }

        lf = linker_make_file(filename, &link_elf_class);
        if (!lf) {
                error = ENOMEM;
                goto out;
        }
        ef = (elf_file_t) lf;
        ef->nprogtab = 0;
        ef->e_shdr = 0;
        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 = malloc(nbytes, M_LINKER, M_WAITOK);
        ef->e_shdr = shdr;
        error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
            hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
            NOCRED, &resid, td);
        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:
#ifdef __amd64__
                case SHT_X86_64_UNWIND:
#endif
                case SHT_INIT_ARRAY:
                case SHT_FINI_ARRAY:
                        if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
                                break;
                        ef->nprogtab++;
                        break;
                case SHT_SYMTAB:
                        nsym++;
                        symtabindex = i;
                        symstrindex = shdr[i].sh_link;
                        break;
                case SHT_REL:
                        /*
                         * Ignore relocation tables for unallocated
                         * sections.
                         */
                        if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
                                break;
                        ef->nreltab++;
                        break;
                case SHT_RELA:
                        if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
                                break;
                        ef->nrelatab++;
                        break;
                case SHT_STRTAB:
                        break;
                }
        }
        if (ef->nprogtab == 0) {
                link_elf_error(filename, "file has no contents");
                error = ENOEXEC;
                goto out;
        }
        if (nsym != 1) {
                /* Only allow one symbol table for now */
                link_elf_error(filename,
                    "file must have exactly one symbol table");
                error = ENOEXEC;
                goto out;
        }
        if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
            shdr[symstrindex].sh_type != SHT_STRTAB) {
                link_elf_error(filename, "file has invalid symbol strings");
                error = ENOEXEC;
                goto out;
        }

        /* Allocate space for tracking the load chunks */
        if (ef->nprogtab != 0)
                ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
                    M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nreltab != 0)
                ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
                    M_LINKER, M_WAITOK | M_ZERO);
        if (ef->nrelatab != 0)
                ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
                    M_LINKER, M_WAITOK | M_ZERO);

        if (symtabindex == -1) {
                link_elf_error(filename, "lost symbol table index");
                error = ENOEXEC;
                goto out;
        }
        /* Allocate space for and load the symbol table */
        ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
        ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
        error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
            shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
            UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
            &resid, td);
        if (error)
                goto out;
        if (resid != 0){
                error = EINVAL;
                goto out;
        }

        /* Allocate space for and load the symbol strings */
        ef->ddbstrcnt = shdr[symstrindex].sh_size;
        ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
        error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
            shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
            UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
            &resid, td);
        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 = malloc(shdr[shstrindex].sh_size, M_LINKER,
                    M_WAITOK);
                error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
                    shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
                    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
                    &resid, td);
                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:
#ifdef __amd64__
                case SHT_X86_64_UNWIND:
#endif
                case SHT_INIT_ARRAY:
                case SHT_FINI_ARRAY:
                        if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
                                break;
                        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_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize),
            VM_PROT_ALL, 0, thread0.td_ucred);
        if (ef->object == NULL) {
                error = ENOMEM;
                goto out;
        }
#if VM_NRESERVLEVEL > 0
        vm_object_color(ef->object, 0);
#endif

        /*
         * In order to satisfy amd64's architectural requirements on the
         * location of code and data in the kernel's address space, request a
         * mapping that is above the kernel.
         *
         * Protections will be restricted once relocations are applied.
         */
#ifdef __amd64__
        mapbase = KERNBASE;
#else
        mapbase = VM_MIN_KERNEL_ADDRESS;
#endif
        error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
            round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
            VM_PROT_ALL, 0);
        if (error != KERN_SUCCESS) {
                vm_object_deallocate(ef->object);
                ef->object = NULL;
                error = ENOMEM;
                goto out;
        }

        /* Wire the pages */
        error = vm_map_wire(kernel_map, mapbase,
            mapbase + round_page(mapsize),
            VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
        if (error != KERN_SUCCESS) {
                error = ENOMEM;
                goto out;
        }

        /* Inform the kld system about the situation */
        lf->address = ef->address = (caddr_t)mapbase;
        lf->size = 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:
#ifdef __amd64__
                case SHT_X86_64_UNWIND:
#endif
                case SHT_INIT_ARRAY:
                case SHT_FINI_ARRAY:
                        if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
                                break;
                        alignmask = shdr[i].sh_addralign - 1;
                        mapbase += alignmask;
                        mapbase &= ~alignmask;
                        if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
                                ef->progtab[pb].name =
                                    ef->shstrtab + shdr[i].sh_name;
                                if (!strcmp(ef->progtab[pb].name, ".ctors") ||
                                    shdr[i].sh_type == SHT_INIT_ARRAY) {
                                        if (lf->ctors_addr != 0) {
                                                printf(
                                    "%s: multiple ctor sections in %s\n",
                                                    __func__, filename);
                                        } else {
                                                lf->ctors_addr =
                                                    (caddr_t)mapbase;
                                                lf->ctors_size =
                                                    shdr[i].sh_size;
                                        }
                                } else if (!strcmp(ef->progtab[pb].name,
                                    ".dtors") ||
                                    shdr[i].sh_type == SHT_FINI_ARRAY) {
                                        if (lf->dtors_addr != 0) {
                                                printf(
                                    "%s: multiple dtor sections in %s\n",
                                                    __func__, filename);
                                        } else {
                                                lf->dtors_addr =
                                                    (caddr_t)mapbase;
                                                lf->dtors_size =
                                                    shdr[i].sh_size;
                                        }
                                }
                        } else if (shdr[i].sh_type == SHT_PROGBITS)
                                ef->progtab[pb].name = "<<PROGBITS>>";
#ifdef __amd64__
                        else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
                                ef->progtab[pb].name = "<<UNWIND>>";
#endif
                        else
                                ef->progtab[pb].name = "<<NOBITS>>";
                        if (ef->progtab[pb].name != NULL && 
                            !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
                                ef->progtab[pb].origaddr =
                                    (void *)(uintptr_t)mapbase;
                                ef->progtab[pb].addr =
                                    dpcpu_alloc(shdr[i].sh_size);
                                if (ef->progtab[pb].addr == NULL) {
                                        printf("%s: pcpu module space is out "
                                            "of space; cannot allocate %#jx "
                                            "for %s\n", __func__,
                                            (uintmax_t)shdr[i].sh_size,
                                            filename);
                                }
                        }
#ifdef VIMAGE
                        else if (ef->progtab[pb].name != NULL &&
                            !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
                                ef->progtab[pb].origaddr =
                                    (void *)(uintptr_t)mapbase;
                                ef->progtab[pb].addr =
                                    vnet_data_alloc(shdr[i].sh_size);
                                if (ef->progtab[pb].addr == NULL) {
                                        printf("%s: vnet module space is out "
                                            "of space; cannot allocate %#jx "
                                            "for %s\n", __func__,
                                            (uintmax_t)shdr[i].sh_size,
                                            filename);
                                }
                        }
#endif
                        else
                                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].flags = shdr[i].sh_flags;
                        ef->progtab[pb].sec = i;
                        if (shdr[i].sh_type == SHT_PROGBITS
#ifdef __amd64__
                            || shdr[i].sh_type == SHT_X86_64_UNWIND
#endif
                            ) {
                                error = vn_rdwr(UIO_READ, nd->ni_vp,
                                    ef->progtab[pb].addr,
                                    shdr[i].sh_size, shdr[i].sh_offset,
                                    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
                                    NOCRED, &resid, td);
                                if (error)
                                        goto out;
                                if (resid != 0){
                                        error = EINVAL;
                                        goto out;
                                }
                                /* Initialize the per-cpu area. */
                                if (ef->progtab[pb].addr != (void *)mapbase &&
                                    !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
                                        dpcpu_copy(ef->progtab[pb].addr,
                                            shdr[i].sh_size);
                        } else
                                bzero(ef->progtab[pb].addr, shdr[i].sh_size);

#ifdef VIMAGE
                        if (ef->progtab[pb].addr != (void *)mapbase &&
                            strcmp(ef->progtab[pb].name, VNET_SETNAME) == 0)
                                vnet_save_init(ef->progtab[pb].addr,
                                    ef->progtab[pb].size);
#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;
                        }
                        mapbase += shdr[i].sh_size;
                        pb++;
                        break;
                case SHT_REL:
                        if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
                                break;
                        ef->reltab[rl].rel = malloc(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, nd->ni_vp,
                            (void *)ef->reltab[rl].rel,
                            shdr[i].sh_size, shdr[i].sh_offset,
                            UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
                            &resid, td);
                        if (error)
                                goto out;
                        if (resid != 0){
                                error = EINVAL;
                                goto out;
                        }
                        rl++;
                        break;
                case SHT_RELA:
                        if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
                                break;
                        ef->relatab[ra].rela = malloc(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, nd->ni_vp,
                            (void *)ef->relatab[ra].rela,
                            shdr[i].sh_size, shdr[i].sh_offset,
                            UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
                            &resid, td);
                        if (error)
                                goto out;
                        if (resid != 0){
                                error = EINVAL;
                                goto out;
                        }
                        ra++;
                        break;
                }
        }
        if (pb != ef->nprogtab) {
                link_elf_error(filename, "lost progbits");
                error = ENOEXEC;
                goto out;
        }
        if (rl != ef->nreltab) {
                link_elf_error(filename, "lost reltab");
                error = ENOEXEC;
                goto out;
        }
        if (ra != ef->nrelatab) {
                link_elf_error(filename, "lost relatab");
                error = ENOEXEC;
                goto out;
        }
        if (mapbase != (vm_offset_t)ef->address + mapsize) {
                printf(
                    "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
                    filename != NULL ? filename : "<none>",
                    (u_long)mapbase, ef->address, (u_long)mapsize,
                    (u_long)(vm_offset_t)ef->address + mapsize);
                error = ENOMEM;
                goto out;
        }

        /* Local intra-module relocations */
        error = link_elf_reloc_local(lf, false);
        if (error != 0)
                goto out;

        /* Pull in dependencies */
        VOP_UNLOCK(nd->ni_vp);
        error = linker_load_dependencies(lf);
        vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
        if (error)
                goto out;

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

        /* Notify MD code that a module is being loaded. */
        error = elf_cpu_load_file(lf);
        if (error)
                goto out;

#if defined(__i386__) || defined(__amd64__)
        /* Now ifuncs. */
        error = link_elf_reloc_local(lf, true);
        if (error != 0)
                goto out;
#endif

        link_elf_protect(ef);
        link_elf_invoke_ctors(lf);
        *result = lf;

out:
        VOP_UNLOCK(nd->ni_vp);
        vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
        free(nd, M_TEMP);
        if (error && lf)
                linker_file_unload(lf, LINKER_UNLOAD_FORCE);
        free(hdr, M_LINKER);

        return error;
}

static void
link_elf_unload_file(linker_file_t file)
{
        elf_file_t ef = (elf_file_t) file;
        u_int i;

        link_elf_invoke_dtors(file);

        /* Notify MD code that a module is being unloaded. */
        elf_cpu_unload_file(file);

        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 (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
                                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
                        else if (ef->preloaded) {
                                vm_offset_t start, end;

                                start = (vm_offset_t)ef->progtab[i].addr;
                                end = start + ef->progtab[i].size;

                                /*
                                 * Reset mapping protections to their original
                                 * state.  This affects the direct map alias of
                                 * the module mapping as well.
                                 */
                                link_elf_protect_range(ef, trunc_page(start),
                                    round_page(end), VM_PROT_RW);
                        }
                }
        }
        if (ef->preloaded) {
                free(ef->reltab, M_LINKER);
                free(ef->relatab, M_LINKER);
                free(ef->progtab, M_LINKER);
                free(ef->ctftab, M_LINKER);
                free(ef->ctfoff, M_LINKER);
                free(ef->typoff, M_LINKER);
                if (file->pathname != NULL)
                        preload_delete_name(file->pathname);
                return;
        }

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

        if (ef->object != NULL)
                vm_map_remove(kernel_map, (vm_offset_t)ef->address,
                    (vm_offset_t)ef->address + ptoa(ef->object->size));
        free(ef->e_shdr, M_LINKER);
        free(ef->ddbsymtab, M_LINKER);
        free(ef->ddbstrtab, M_LINKER);
        free(ef->shstrtab, M_LINKER);
        free(ef->ctftab, M_LINKER);
        free(ef->ctfoff, M_LINKER);
        free(ef->typoff, 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_file1(elf_file_t ef, bool ifuncs)
{
        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) {
                        link_elf_error(ef->lf.filename, "lost a reltab!");
                        return (ENOEXEC);
                }
                rellim = rel + ef->reltab[i].nrel;
                base = findbase(ef, ef->reltab[i].sec);
                if (base == 0) {
                        link_elf_error(ef->lf.filename, "lost base for reltab");
                        return (ENOEXEC);
                }
                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_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
                            elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
                                continue;
                        if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
                            elf_obj_lookup)) {
                                symname = symbol_name(ef, rel->r_info);
                                printf("link_elf_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) {
                        link_elf_error(ef->lf.filename, "lost a relatab!");
                        return (ENOEXEC);
                }
                relalim = rela + ef->relatab[i].nrela;
                base = findbase(ef, ef->relatab[i].sec);
                if (base == 0) {
                        link_elf_error(ef->lf.filename,
                            "lost base for relatab");
                        return (ENOEXEC);
                }
                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_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
                            elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
                                continue;
                        if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
                            elf_obj_lookup)) {
                                symname = symbol_name(ef, rela->r_info);
                                printf("link_elf_obj: symbol %s undefined\n",
                                    symname);
                                return (ENOENT);
                        }
                }
        }

        /*
         * Only clean SHN_FBSD_CACHED for successful return.  If we
         * modified symbol table for the object but found an
         * unresolved symbol, there is no reason to roll back.
         */
        elf_obj_cleanup_globals_cache(ef);

        return (0);
}

static int
relocate_file(elf_file_t ef)
{
        int error;

        error = relocate_file1(ef, false);
        if (error == 0)
                error = relocate_file1(ef, true);
        return (error);
}

static int
link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
    bool see_local)
{
        elf_file_t ef = (elf_file_t)lf;
        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) {
                        if (see_local ||
                            ELF_ST_BIND(symp->st_info) == STB_GLOBAL) {
                                *sym = (c_linker_sym_t) symp;
                                return (0);
                        }
                        return (ENOENT);
                }
        }
        return (ENOENT);
}

static int
link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
{
        return (link_elf_lookup_symbol1(lf, name, sym,
            link_elf_obj_leak_locals));
}

static int
link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
    c_linker_sym_t *sym)
{
        return (link_elf_lookup_symbol1(lf, name, sym, true));
}

static int
link_elf_lookup_debug_symbol_ctf(linker_file_t lf, const char *name,
    c_linker_sym_t *sym, linker_ctf_t *lc)
{
        if (link_elf_lookup_debug_symbol(lf, name, sym))
                return (ENOENT);

        return (link_elf_ctf_get_ddb(lf, lc));
}

static void
link_elf_ifunc_symbol_value(linker_file_t lf, caddr_t *valp, size_t *sizep)
{
        c_linker_sym_t sym;
        const Elf_Sym *es;
        caddr_t val;
        long off;

        val = *valp;

        /* Provide the value and size of the target symbol, if available. */
        val = ((caddr_t (*)(void))val)();
        if (link_elf_search_symbol(lf, val, &sym, &off) == 0 && off == 0) {
                es = (const Elf_Sym *)sym;
                *valp = (caddr_t)es->st_value;
                *sizep = es->st_size;
        } else {
                *valp = val;
                *sizep = 0;
        }
}

static int
link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
    linker_symval_t *symval, bool see_local)
{
        elf_file_t ef;
        const Elf_Sym *es;
        caddr_t val;
        size_t size;

        ef = (elf_file_t) lf;
        es = (const Elf_Sym*) sym;
        val = (caddr_t)es->st_value;
        if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
                if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
                        return (ENOENT);
                symval->name = ef->ddbstrtab + es->st_name;
                val = (caddr_t)es->st_value;
                if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
                        link_elf_ifunc_symbol_value(lf, &val, &size);
                else
                        size = es->st_size;
                symval->value = val;
                symval->size = size;
                return (0);
        }
        return (ENOENT);
}

static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
    linker_symval_t *symval)
{
        return (link_elf_symbol_values1(lf, sym, symval,
            link_elf_obj_leak_locals));
}

static int
link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
    linker_symval_t *symval)
{
        return (link_elf_symbol_values1(lf, sym, symval, true));
}

static int
link_elf_search_symbol(linker_file_t lf, caddr_t value,
    c_linker_sym_t *sym, long *diffp)
{
        elf_file_t ef = (elf_file_t)lf;
        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_lookup_set(linker_file_t lf, const char *name,
    void ***startp, void ***stopp, int *countp)
{
        elf_file_t ef = (elf_file_t)lf;
        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);
}

static int
link_elf_each_function_name(linker_file_t file,
    int (*callback)(const char *, void *), void *opaque)
{
        elf_file_t ef = (elf_file_t)file;
        const Elf_Sym *symp;
        int i, error;

        /* Exhaustive search */
        for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
                if (symp->st_value != 0 &&
                    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
                    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
                        error = callback(ef->ddbstrtab + symp->st_name, opaque);
                        if (error)
                                return (error);
                }
        }
        return (0);
}

static int
link_elf_each_function_nameval(linker_file_t file,
    linker_function_nameval_callback_t callback, void *opaque)
{
        linker_symval_t symval;
        elf_file_t ef = (elf_file_t)file;
        const Elf_Sym *symp;
        int i, error;

        /* Exhaustive search */
        for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
                if (symp->st_value != 0 &&
                    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
                    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
                        error = link_elf_debug_symbol_values(file,
                            (c_linker_sym_t)symp, &symval);
                        if (error == 0)
                                error = callback(file, i, &symval, opaque);
                        if (error != 0)
                                return (error);
                }
        }
        return (0);
}

static void
elf_obj_cleanup_globals_cache(elf_file_t ef)
{
        Elf_Sym *sym;
        Elf_Size i;

        for (i = 0; i < ef->ddbsymcnt; i++) {
                sym = ef->ddbsymtab + i;
                if (sym->st_shndx == SHN_FREEBSD_CACHED) {
                        sym->st_shndx = SHN_UNDEF;
                        sym->st_value = 0;
                }
        }
}

/*
 * 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 *res)
{
        elf_file_t ef = (elf_file_t)lf;
        Elf_Sym *sym;
        const char *symbol;
        Elf_Addr res1;

        /* Don't even try to lookup the symbol if the index is bogus. */
        if (symidx >= ef->ddbsymcnt) {
                *res = 0;
                return (EINVAL);
        }

        sym = ef->ddbsymtab + symidx;

        /* Quick answer if there is a definition included. */
        if (sym->st_shndx != SHN_UNDEF) {
                res1 = (Elf_Addr)sym->st_value;
                if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
                        res1 = ((Elf_Addr (*)(void))res1)();
                *res = res1;
                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? */
                *res = 0;
                return (EINVAL);

        case STB_GLOBAL:
        case STB_WEAK:
                /* 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) {
                        *res = 0;
                        return (EINVAL);
                }
                res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);

                /*
                 * Cache global lookups during module relocation. The failure
                 * case is particularly expensive for callers, who must scan
                 * through the entire globals table doing strcmp(). Cache to
                 * avoid doing such work repeatedly.
                 *
                 * After relocation is complete, undefined globals will be
                 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
                 * above.
                 */
                if (res1 != 0) {
                        sym->st_shndx = SHN_FREEBSD_CACHED;
                        sym->st_value = res1;
                        *res = res1;
                        return (0);
                } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
                        sym->st_value = 0;
                        *res = 0;
                        return (0);
                }
                return (EINVAL);

        default:
                return (EINVAL);
        }
}

static void
link_elf_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 int
link_elf_reloc_local(linker_file_t lf, bool ifuncs)
{
        elf_file_t ef = (elf_file_t)lf;
        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_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) {
                        link_elf_error(ef->lf.filename, "lost a reltab");
                        return (ENOEXEC);
                }
                rellim = rel + ef->reltab[i].nrel;
                base = findbase(ef, ef->reltab[i].sec);
                if (base == 0) {
                        link_elf_error(ef->lf.filename, "lost base for reltab");
                        return (ENOEXEC);
                }
                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;
                        if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
                            elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
                                continue;
                        if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
                            elf_obj_lookup) != 0)
                                return (ENOEXEC);
                }
        }

        /* Perform relocations with addend if there are any: */
        for (i = 0; i < ef->nrelatab; i++) {
                rela = ef->relatab[i].rela;
                if (rela == NULL) {
                        link_elf_error(ef->lf.filename, "lost a relatab!");
                        return (ENOEXEC);
                }
                relalim = rela + ef->relatab[i].nrela;
                base = findbase(ef, ef->relatab[i].sec);
                if (base == 0) {
                        link_elf_error(ef->lf.filename, "lost base for reltab");
                        return (ENOEXEC);
                }
                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;
                        if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
                            elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
                                continue;
                        if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
                            elf_obj_lookup) != 0)
                                return (ENOEXEC);
                }
        }
        return (0);
}

static long
link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
{
        elf_file_t ef = (elf_file_t)lf;

        *symtab = ef->ddbsymtab;
        if (*symtab == NULL)
                return (0);
        return (ef->ddbsymcnt);
}

static long
link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
{
        elf_file_t ef = (elf_file_t)lf;

        *strtab = ef->ddbstrtab;
        if (*strtab == NULL)
                return (0);
        return (ef->ddbstrcnt);
}

#ifdef VIMAGE
static void
link_elf_propagate_vnets(linker_file_t lf)
{
        elf_file_t ef = (elf_file_t) lf;

        if (ef->progtab) {
                for (int i = 0; i < ef->nprogtab; i++) {
                        if (ef->progtab[i].size == 0)
                                continue;
                        if (ef->progtab[i].name == NULL)
                                continue;
                        if (strcmp(ef->progtab[i].name, VNET_SETNAME) == 0) {
                                vnet_data_copy(ef->progtab[i].addr,
                                    ef->progtab[i].size);
                                break;
                        }
                }
        }
}
#endif