text: /*-
   * Copyright (c) 1998-2000 Doug Rabson
   * 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 <sys/cdefs.h>
  __FBSDID("$FreeBSD: src/sys/kern/link_elf.c,v 1.76 2003/08/11 07:14:07 bms Exp $");
  
  #include "opt_ddb.h"
  #include "opt_mac.h"
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/kernel.h>
  #include <sys/lock.h>
  #include <sys/mac.h>
  #include <sys/malloc.h>
  #include <sys/mutex.h>
  #include <sys/proc.h>
  #include <sys/namei.h>
  #include <sys/fcntl.h>
  #include <sys/vnode.h>
  #include <sys/linker.h>
  
  #include <machine/elf.h>
  #ifdef GPROF
  #include <machine/profile.h>
  #endif
  
  #include <vm/vm.h>
  #include <vm/vm_param.h>
  #ifdef SPARSE_MAPPING
  #include <vm/vm_object.h>
  #include <vm/vm_kern.h>
  #include <vm/vm_extern.h>
  #endif
  #include <vm/pmap.h>
  #include <vm/vm_map.h>
  
  #include <sys/link_elf.h>
  
  #include "linker_if.h"
  
  typedef struct elf_file {
      struct linker_file	lf;		/* Common fields */
      int			preloaded;	/* Was file pre-loaded */
      caddr_t		address;	/* Relocation address */
  #ifdef SPARSE_MAPPING
      vm_object_t		object;		/* VM object to hold file pages */
  #endif
      Elf_Dyn*		dynamic;	/* Symbol table etc. */
      Elf_Hashelt		nbuckets;	/* DT_HASH info */
      Elf_Hashelt		nchains;
      const Elf_Hashelt*	buckets;
      const Elf_Hashelt*	chains;
      caddr_t		hash;
      caddr_t		strtab;		/* DT_STRTAB */
      int			strsz;		/* DT_STRSZ */
      const Elf_Sym*	symtab;		/* DT_SYMTAB */
      Elf_Addr*		got;		/* DT_PLTGOT */
      const Elf_Rel*	pltrel;		/* DT_JMPREL */
      int			pltrelsize;	/* DT_PLTRELSZ */
      const Elf_Rela*	pltrela;	/* DT_JMPREL */
      int			pltrelasize;	/* DT_PLTRELSZ */
      const Elf_Rel*	rel;		/* DT_REL */
      int			relsize;	/* DT_RELSZ */
      const Elf_Rela*	rela;		/* DT_RELA */
      int			relasize;	/* DT_RELASZ */
      caddr_t		modptr;
      const 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		symbase;	/* malloc'ed symbold base */
      caddr_t		strbase;	/* malloc'ed string base */
  #ifdef DDB
      struct link_map	gdb;		/* hooks for gdb */
  #endif
  } *elf_file_t;
  
  static int	link_elf_link_common_finish(linker_file_t);
  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_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 void	link_elf_unload_preload(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 void	link_elf_reloc_local(linker_file_t);
  
  static kobj_method_t link_elf_methods[] = {
      KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
      KOBJMETHOD(linker_symbol_values,	link_elf_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),
      { 0, 0 }
  };
  
  static struct linker_class link_elf_class = {
  #if ELF_TARG_CLASS == ELFCLASS32
      "elf32",
  #else
      "elf64",
  #endif
      link_elf_methods, sizeof(struct elf_file)
  };
  
  static int		parse_dynamic(elf_file_t ef);
  static int		relocate_file(elf_file_t ef);
  static int		link_elf_preload_parse_symbols(elf_file_t ef);
  
  #ifdef DDB
  static void		r_debug_state(struct r_debug *dummy_one,
  				      struct link_map *dummy_two);
  
  /*
   * A list of loaded modules for GDB to use for loading symbols.
   */
  struct r_debug r_debug;
  
  #define GDB_STATE(s)	r_debug.r_state = s; r_debug_state(NULL, NULL);
  
  /*
   * Function for the debugger to set a breakpoint on to gain control.
   */
  static void
  r_debug_state(struct r_debug *dummy_one __unused,
  	      struct link_map *dummy_two __unused)
  {
  }
  
  static void
  link_elf_add_gdb(struct link_map *l)
  {
      struct link_map *prev;
  
      l->l_next = NULL;
  
      if (r_debug.r_map == NULL) {
  	/* Add first. */
  	l->l_prev = NULL;
  	r_debug.r_map = l;
      } else {
  	/* Append to list. */
  	for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
  	    ;
  	l->l_prev = prev;
  	prev->l_next = l;
      }
  }
  
  static void
  link_elf_delete_gdb(struct link_map *l)
  {
      if (l->l_prev == NULL) {
  	/* Remove first. */
  	if ((r_debug.r_map = l->l_next) != NULL)
  	    l->l_next->l_prev = NULL;
      } else {
  	/* Remove any but first. */
  	if ((l->l_prev->l_next = l->l_next) != NULL)
  	    l->l_next->l_prev = l->l_prev;
      }
  }
  #endif /* DDB */
  
  #ifdef __ia64__
  Elf_Addr link_elf_get_gp(linker_file_t);
  #endif
  
  /*
   * The kernel symbol table starts here.
   */
  extern struct _dynamic _DYNAMIC;
  
  static void
  link_elf_error(const char *s)
  {
      printf("kldload: %s\n", s);
  }
  
  /*
   * Actions performed after linking/loading both the preloaded kernel and any
   * modules; whether preloaded or dynamicly loaded.
   */
  static int
  link_elf_link_common_finish(linker_file_t lf)
  {
  #ifdef DDB
      elf_file_t ef = (elf_file_t)lf;
      char *newfilename;
  #endif
      int error;
  
      /* Notify MD code that a module is being loaded. */
      error = elf_cpu_load_file(lf);
      if (error)
  	return (error);
  
  #ifdef DDB
      GDB_STATE(RT_ADD);
      ef->gdb.l_addr = lf->address;
      newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
      strcpy(newfilename, lf->filename);
      ef->gdb.l_name = newfilename;
      ef->gdb.l_ld = ef->dynamic;
      link_elf_add_gdb(&ef->gdb);
      GDB_STATE(RT_CONSISTENT);
  #endif
  
      return (0);
  }
  
  static void
  link_elf_init(void* arg)
  {
      Elf_Dyn	*dp;
      caddr_t	modptr, baseptr, sizeptr;
      elf_file_t	ef;
      char	*modname;
  
      linker_add_class(&link_elf_class);
  
      dp = (Elf_Dyn*) &_DYNAMIC;
      modname = NULL;
      modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
      if (modptr == NULL)
  	modptr = preload_search_by_type("elf kernel");
      if (modptr)
  	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
      if (modname == NULL)
  	modname = "kernel";
      linker_kernel_file = linker_make_file(modname, &link_elf_class);
      if (linker_kernel_file == NULL)
  	panic("link_elf_init: Can't create linker structures for kernel");
  
      ef = (elf_file_t) linker_kernel_file;
      ef->preloaded = 1;
      ef->address = 0;
  #ifdef SPARSE_MAPPING
      ef->object = 0;
  #endif
      ef->dynamic = dp;
  
      if (dp)
  	parse_dynamic(ef);
      linker_kernel_file->address = (caddr_t) KERNBASE;
      linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
  
      if (modptr) {
  	ef->modptr = modptr;
  	baseptr = preload_search_info(modptr, MODINFO_ADDR);
  	if (baseptr)
  	    linker_kernel_file->address = *(caddr_t *)baseptr;
  	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  	if (sizeptr)
  	    linker_kernel_file->size = *(size_t *)sizeptr;
      }
      (void)link_elf_preload_parse_symbols(ef);
  
  #ifdef DDB
      r_debug.r_map = NULL;
      r_debug.r_brk = r_debug_state;
      r_debug.r_state = RT_CONSISTENT;
  #endif
  
      (void)link_elf_link_common_finish(linker_kernel_file);
  }
  
  SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
  
  static int
  link_elf_preload_parse_symbols(elf_file_t ef)
  {
      caddr_t	pointer;
      caddr_t	ssym, esym, base;
      caddr_t	strtab;
      int		strcnt;
      Elf_Sym*	symtab;
      int		symcnt;
  
      if (ef->modptr == NULL)
  	return 0;
      pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
      if (pointer == NULL)
  	return 0;
      ssym = *(caddr_t *)pointer;
      pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
      if (pointer == NULL)
  	return 0;
      esym = *(caddr_t *)pointer;
  
      base = ssym;
  
      symcnt = *(long *)base;
      base += sizeof(long);
      symtab = (Elf_Sym *)base;
      base += roundup(symcnt, sizeof(long));
  
      if (base > esym || base < ssym) {
  	printf("Symbols are corrupt!\n");
  	return EINVAL;
      }
  
      strcnt = *(long *)base;
      base += sizeof(long);
      strtab = base;
      base += roundup(strcnt, sizeof(long));
  
      if (base > esym || base < ssym) {
  	printf("Symbols are corrupt!\n");
  	return EINVAL;
      }
  
      ef->ddbsymtab = symtab;
      ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
      ef->ddbstrtab = strtab;
      ef->ddbstrcnt = strcnt;
  
      return 0;
  }
  
  static int
  parse_dynamic(elf_file_t ef)
  {
      Elf_Dyn *dp;
      int plttype = DT_REL;
  
      for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  	switch (dp->d_tag) {
  	case DT_HASH:
  	{
  	    /* From src/libexec/rtld-elf/rtld.c */
  	    const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
  		(ef->address + dp->d_un.d_ptr);
  	    ef->nbuckets = hashtab[0];
  	    ef->nchains = hashtab[1];
  	    ef->buckets = hashtab + 2;
  	    ef->chains = ef->buckets + ef->nbuckets;
  	    break;
  	}
  	case DT_STRTAB:
  	    ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
  	    break;
  	case DT_STRSZ:
  	    ef->strsz = dp->d_un.d_val;
  	    break;
  	case DT_SYMTAB:
  	    ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
  	    break;
  	case DT_SYMENT:
  	    if (dp->d_un.d_val != sizeof(Elf_Sym))
  		return ENOEXEC;
  	    break;
  	case DT_PLTGOT:
  	    ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
  	    break;
  	case DT_REL:
  	    ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
  	    break;
  	case DT_RELSZ:
  	    ef->relsize = dp->d_un.d_val;
  	    break;
  	case DT_RELENT:
  	    if (dp->d_un.d_val != sizeof(Elf_Rel))
  		return ENOEXEC;
  	    break;
  	case DT_JMPREL:
  	    ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
  	    break;
  	case DT_PLTRELSZ:
  	    ef->pltrelsize = dp->d_un.d_val;
  	    break;
  	case DT_RELA:
  	    ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
  	    break;
  	case DT_RELASZ:
  	    ef->relasize = dp->d_un.d_val;
  	    break;
  	case DT_RELAENT:
  	    if (dp->d_un.d_val != sizeof(Elf_Rela))
  		return ENOEXEC;
  	    break;
  	case DT_PLTREL:
  	    plttype = dp->d_un.d_val;
  	    if (plttype != DT_REL && plttype != DT_RELA)
  		return ENOEXEC;
  	    break;
  #ifdef DDB
  	case DT_DEBUG:
  	    dp->d_un.d_ptr = (Elf_Addr) &r_debug;
  	    break;
  #endif
  	}
      }
  
      if (plttype == DT_RELA) {
  	ef->pltrela = (const Elf_Rela *) ef->pltrel;
  	ef->pltrel = NULL;
  	ef->pltrelasize = ef->pltrelsize;
  	ef->pltrelsize = 0;
      }
  
      ef->ddbsymtab = ef->symtab;
      ef->ddbsymcnt = ef->nchains;
      ef->ddbstrtab = ef->strtab;
      ef->ddbstrcnt = ef->strsz;
  
      return 0;
  }
  
  static int
  link_elf_link_preload(linker_class_t cls,
  		      const char* filename, linker_file_t *result)
  {
      caddr_t		modptr, baseptr, sizeptr, dynptr;
      char		*type;
      elf_file_t		ef;
      linker_file_t	lf;
      int			error;
      vm_offset_t		dp;
  
      /* 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);
      dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
      if (type == NULL ||
  	(strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
  	 strcmp(type, "elf module") != 0))
  	return (EFTYPE);
      if (baseptr == NULL || sizeptr == NULL || dynptr == 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->modptr = modptr;
      ef->address = *(caddr_t *)baseptr;
  #ifdef SPARSE_MAPPING
      ef->object = 0;
  #endif
      dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
      ef->dynamic = (Elf_Dyn *)dp;
      lf->address = ef->address;
      lf->size = *(size_t *)sizeptr;
  
      error = parse_dynamic(ef);
      if (error) {
  	linker_file_unload(lf);
  	return error;
      }
      link_elf_reloc_local(lf);
      *result = lf;
      return (0);
  }
  
  static int
  link_elf_link_preload_finish(linker_file_t lf)
  {
      elf_file_t		ef;
      int error;
  
      ef = (elf_file_t) lf;
  #if 0	/* this will be more trouble than it's worth for now */
      for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  	if (dp->d_tag != DT_NEEDED)
  	    continue;
  	modname = ef->strtab + dp->d_un.d_val;
  	error = linker_load_module(modname, lf);
  	if (error)
  	    goto out;
      }
  #endif
      error = relocate_file(ef);
      if (error)
  	return error;
      (void)link_elf_preload_parse_symbols(ef);
  
      return (link_elf_link_common_finish(lf));
  }
  
  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;
      caddr_t firstpage;
      int nbytes, i;
      Elf_Phdr *phdr;
      Elf_Phdr *phlimit;
      Elf_Phdr *segs[2];
      int nsegs;
      Elf_Phdr *phdyn;
      Elf_Phdr *phphdr;
      caddr_t mapbase;
      size_t mapsize;
      Elf_Off base_offset;
      Elf_Addr base_vaddr;
      Elf_Addr base_vlimit;
      int error = 0;
      int resid, flags;
      elf_file_t ef;
      linker_file_t lf;
      Elf_Shdr *shdr;
      int symtabindex;
      int symstrindex;
      int symcnt;
      int strcnt;
  
      GIANT_REQUIRED;
  
      shdr = NULL;
      lf = NULL;
  
      NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
      flags = FREAD;
      error = vn_open(&nd, &flags, 0, -1);
      if (error)
  	return error;
      NDFREE(&nd, NDF_ONLY_PNBUF);
  #ifdef MAC
      error = mac_check_kld_load(curthread->td_ucred, nd.ni_vp);
      if (error) {
  	firstpage = NULL;
  	goto out;
      }
  #endif
  
      /*
       * Read the elf header from the file.
       */
      firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
      if (firstpage == NULL) {
  	error = ENOMEM;
  	goto out;
      }
      hdr = (Elf_Ehdr *)firstpage;
      error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
  		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  		    &resid, td);
      nbytes = PAGE_SIZE - resid;
      if (error)
  	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("Unsupported file layout");
  	error = ENOEXEC;
  	goto out;
      }
      if (hdr->e_ident[EI_VERSION] != EV_CURRENT
        || hdr->e_version != EV_CURRENT) {
  	link_elf_error("Unsupported file version");
  	error = ENOEXEC;
  	goto out;
      }
      if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
  	link_elf_error("Unsupported file type");
  	error = ENOEXEC;
  	goto out;
      }
      if (hdr->e_machine != ELF_TARG_MACH) {
  	link_elf_error("Unsupported machine");
  	error = ENOEXEC;
  	goto out;
      }
  
      /*
       * We rely on the program header being in the first page.  This is
       * not strictly required by the ABI specification, but it seems to
       * always true in practice.  And, it simplifies things considerably.
       */
      if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
  	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
  	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
  	link_elf_error("Unreadable program headers");
  
      /*
       * Scan the program header entries, and save key information.
       *
       * We rely on there being exactly two load segments, text and data,
       * in that order.
       */
      phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
      phlimit = phdr + hdr->e_phnum;
      nsegs = 0;
      phdyn = NULL;
      phphdr = NULL;
      while (phdr < phlimit) {
  	switch (phdr->p_type) {
  
  	case PT_LOAD:
  	    if (nsegs == 2) {
  		link_elf_error("Too many sections");
  		error = ENOEXEC;
  		goto out;
  	    }
  	    /*
  	     * XXX: We just trust they come in right order ??
  	     */
  	    segs[nsegs] = phdr;
  	    ++nsegs;
  	    break;
  
  	case PT_PHDR:
  	    phphdr = phdr;
  	    break;
  
  	case PT_DYNAMIC:
  	    phdyn = phdr;
  	    break;
  
  	case PT_INTERP:
  	    link_elf_error("Unsupported file type");
  	    error = ENOEXEC;
  	    goto out;
  	}
  
  	++phdr;
      }
      if (phdyn == NULL) {
  	link_elf_error("Object is not dynamically-linked");
  	error = ENOEXEC;
  	goto out;
      }
      if (nsegs != 2) {
  	link_elf_error("Too few sections");
  	error = ENOEXEC;
  	goto out;
      }
  
      /*
       * Allocate the entire address space of the object, to stake out our
       * contiguous region, and to establish the base address for relocation.
       */
      base_offset = trunc_page(segs[0]->p_offset);
      base_vaddr = trunc_page(segs[0]->p_vaddr);
      base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
      mapsize = base_vlimit - base_vaddr;
  
      lf = linker_make_file(filename, &link_elf_class);
      if (!lf) {
  	error = ENOMEM;
  	goto out;
      }
  
      ef = (elf_file_t) lf;
  #ifdef SPARSE_MAPPING
      ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
      if (ef->object == NULL) {
  	error = ENOMEM;
  	goto out;
      }
      vm_object_reference(ef->object);
      ef->address = (caddr_t) vm_map_min(kernel_map);
      error = vm_map_find(kernel_map, ef->object, 0,
  			(vm_offset_t *) &ef->address,
  			mapsize, 1,
  			VM_PROT_ALL, VM_PROT_ALL, 0);
      if (error) {
  	vm_object_deallocate(ef->object);
  	ef->object = 0;
  	goto out;
      }
  #else
      ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
      if (!ef->address) {
  	error = ENOMEM;
  	goto out;
      }
  #endif
      mapbase = ef->address;
  
      /*
       * Read the text and data sections and zero the bss.
       */
      for (i = 0; i < 2; i++) {
  	caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
  	error = vn_rdwr(UIO_READ, nd.ni_vp,
  			segbase, segs[i]->p_filesz, segs[i]->p_offset,
  			UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  			&resid, td);
  	if (error) {
  	    goto out;
  	}
  	bzero(segbase + segs[i]->p_filesz,
  	      segs[i]->p_memsz - segs[i]->p_filesz);
  
  #ifdef SPARSE_MAPPING
  	/*
  	 * Wire down the pages
  	 */
  	vm_map_wire(kernel_map,
  		    (vm_offset_t) segbase,
  		    (vm_offset_t) segbase + segs[i]->p_memsz,
  		    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  #endif
      }
  
  #ifdef GPROF
      /* Update profiling information with the new text segment. */
      kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
  	segs[0]->p_memsz));
  #endif
  
      ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
  
      lf->address = ef->address;
      lf->size = mapsize;
  
      error = parse_dynamic(ef);
      if (error)
  	goto out;
      link_elf_reloc_local(lf);
  
      error = linker_load_dependencies(lf);
      if (error)
  	goto out;
  #if 0	/* this will be more trouble than it's worth for now */
      for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  	if (dp->d_tag != DT_NEEDED)
  	    continue;
  	modname = ef->strtab + dp->d_un.d_val;
  	error = linker_load_module(modname, lf);
  	if (error)
  	    goto out;
      }
  #endif
      error = relocate_file(ef);
      if (error)
  	goto out;
  
      /* Try and load the symbol table if it's present.  (you can strip it!) */
      nbytes = hdr->e_shnum * hdr->e_shentsize;
      if (nbytes == 0 || hdr->e_shoff == 0)
  	goto nosyms;
      shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
      if (shdr == NULL) {
  	error = ENOMEM;
  	goto out;
      }
      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;
      symtabindex = -1;
      symstrindex = -1;
      for (i = 0; i < hdr->e_shnum; i++) {
  	if (shdr[i].sh_type == SHT_SYMTAB) {
  	    symtabindex = i;
  	    symstrindex = shdr[i].sh_link;
  	}
      }
      if (symtabindex < 0 || symstrindex < 0)
  	goto nosyms;
  
      symcnt = shdr[symtabindex].sh_size;
      ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
      strcnt = shdr[symstrindex].sh_size;
      ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
  
      if (ef->symbase == NULL || ef->strbase == NULL) {
  	error = ENOMEM;
  	goto out;
      }
      error = vn_rdwr(UIO_READ, nd.ni_vp,
  		    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
  		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  		    &resid, td);
      if (error)
  	goto out;
      error = vn_rdwr(UIO_READ, nd.ni_vp,
  		    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
  		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  		    &resid, td);
      if (error)
  	goto out;
  
      ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
      ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
      ef->ddbstrcnt = strcnt;
      ef->ddbstrtab = ef->strbase;
  
      error = link_elf_link_common_finish(lf);
      if (error)
  	goto out;
  
  nosyms:
  
      *result = lf;
  
  out:
      if (error && lf)
  	linker_file_unload(lf);
      if (shdr)
  	free(shdr, M_LINKER);
      if (firstpage)
  	free(firstpage, M_LINKER);
      VOP_UNLOCK(nd.ni_vp, 0, td);
      vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  
      return error;
  }
  
  static void
  link_elf_unload_file(linker_file_t file)
  {
      elf_file_t ef = (elf_file_t) file;
  
  #ifdef DDB
      if (ef->gdb.l_ld) {
  	GDB_STATE(RT_DELETE);
  	free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
  	link_elf_delete_gdb(&ef->gdb);
  	GDB_STATE(RT_CONSISTENT);
      }
  #endif
  
      /* Notify MD code that a module is being unloaded. */
      elf_cpu_unload_file(file);
  
      if (ef->preloaded) {
  	link_elf_unload_preload(file);
  	return;
      }
  
  #ifdef SPARSE_MAPPING
      if (ef->object) {
  	vm_map_remove(kernel_map, (vm_offset_t) ef->address,
  		      (vm_offset_t) ef->address
  		      + (ef->object->size << PAGE_SHIFT));
  	vm_object_deallocate(ef->object);
      }
  #else
      if (ef->address)
  	free(ef->address, M_LINKER);
  #endif
      if (ef->symbase)
  	free(ef->symbase, M_LINKER);
      if (ef->strbase)
  	free(ef->strbase, M_LINKER);
  }
  
  static void
  link_elf_unload_preload(linker_file_t file)
  {
      if (file->filename)
  	preload_delete_name(file->filename);
  }
  
  static const char *
  symbol_name(elf_file_t ef, Elf_Word r_info)
  {
      const Elf_Sym *ref;
  
      if (ELF_R_SYM(r_info)) {
  	ref = ef->symtab + ELF_R_SYM(r_info);
  	return ef->strtab + ref->st_name;
      } else
  	return NULL;
  }
  
  static int
  relocate_file(elf_file_t ef)
  {
      const Elf_Rel *rellim;
      const Elf_Rel *rel;
      const Elf_Rela *relalim;
      const Elf_Rela *rela;
      const char *symname;
  
      /* Perform relocations without addend if there are any: */
      rel = ef->rel;
      if (rel) {
  	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
  	while (rel < rellim) {
  	    if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) {
  		symname = symbol_name(ef, rel->r_info);
  		printf("link_elf: symbol %s undefined\n", symname);
  		return ENOENT;
  	    }
  	    rel++;
  	}
      }
  
      /* Perform relocations with addend if there are any: */
      rela = ef->rela;
      if (rela) {
  	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
  	while (rela < relalim) {
  	    if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) {
  		symname = symbol_name(ef, rela->r_info);
  		printf("link_elf: symbol %s undefined\n", symname);
  		return ENOENT;
  	    }
  	    rela++;
  	}
      }
  
      /* Perform PLT relocations without addend if there are any: */
      rel = ef->pltrel;
      if (rel) {
  	rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
  	while (rel < rellim) {
  	    if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) {
  		symname = symbol_name(ef, rel->r_info);
  		printf("link_elf: symbol %s undefined\n", symname);
  		return ENOENT;
  	    }
  	    rel++;
  	}
      }
  
      /* Perform relocations with addend if there are any: */
      rela = ef->pltrela;
      if (rela) {
  	relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
  	while (rela < relalim) {
  	    if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) {
  		symname = symbol_name(ef, rela->r_info);
  		printf("link_elf: symbol %s undefined\n", symname);
  		return ENOENT;
  	    }
  	    rela++;
  	}
      }
  
      return 0;
  }
  
  /*
   * Hash function for symbol table lookup.  Don't even think about changing
   * this.  It is specified by the System V ABI.
   */
  static unsigned long
  elf_hash(const char *name)
  {
      const unsigned char *p = (const unsigned char *) name;
      unsigned long h = 0;
      unsigned long g;
  
      while (*p != '\0') {
  	h = (h << 4) + *p++;
  	if ((g = h & 0xf0000000) != 0)
  	    h ^= g >> 24;
  	h &= ~g;
      }
      return h;
  }
  
  static int
  link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
  {
      elf_file_t ef = (elf_file_t) lf;
      unsigned long symnum;
      const Elf_Sym* symp;
      const char *strp;
      unsigned long hash;
      int i;
  
      /* First, search hashed global symbols */
      hash = elf_hash(name);
      symnum = ef->buckets[hash % ef->nbuckets];
  
      while (symnum != STN_UNDEF) {
  	if (symnum >= ef->nchains) {
  	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
  	    return ENOENT;
  	}
  
  	symp = ef->symtab + symnum;
  	if (symp->st_name == 0) {
  	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
  	    return ENOENT;
  	}
  
  	strp = ef->strtab + symp->st_name;
  
  	if (strcmp(name, strp) == 0) {
  	    if (symp->st_shndx != SHN_UNDEF ||
  		(symp->st_value != 0 &&
  		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
  		*sym = (c_linker_sym_t) symp;
  		return 0;
  	    } else
  		return ENOENT;
  	}
  
  	symnum = ef->chains[symnum];
      }
  
      /* If we have not found it, look at the full table (if loaded) */
      if (ef->symtab == ef->ddbsymtab)
  	return ENOENT;
  
      /* Exhaustive search */
      for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
  	strp = ef->ddbstrtab + symp->st_name;
  	if (strcmp(name, strp) == 0) {
  	    if (symp->st_shndx != SHN_UNDEF ||
  		(symp->st_value != 0 &&
  		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
  		*sym = (c_linker_sym_t) symp;
  		return 0;
  	    } else
  		return ENOENT;
  	}
      }
  
      return ENOENT;
  }
  
  static int
  link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
  {
  	elf_file_t ef = (elf_file_t) lf;
  	const Elf_Sym* es = (const Elf_Sym*) sym;
  
  	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
  	    symval->name = ef->strtab + es->st_name;
  	    symval->value = (caddr_t) ef->address + es->st_value;
  	    symval->size = es->st_size;
  	    return 0;
  	}
  	if (ef->symtab == ef->ddbsymtab)
  	    return ENOENT;
  	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
  	    symval->name = ef->ddbstrtab + es->st_name;
  	    symval->value = (caddr_t) ef->address + es->st_value;
  	    symval->size = es->st_size;
  	    return 0;
  	}
  	return ENOENT;
  }
  
  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 = 0;
  	int i;
  
  	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
  		if (es->st_name == 0)
  			continue;
  		st_value = es->st_value + (uintptr_t) (void *) ef->address;
  		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 == 0)
  		*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)
  {
  	c_linker_sym_t sym;
  	linker_symval_t symval;
  	char *setsym;
  	void **start, **stop;
  	int len, error = 0, count;
  
  	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
  	setsym = malloc(len, M_LINKER, M_WAITOK);
  	if (setsym == NULL)
  		return ENOMEM;
  
  	/* get address of first entry */
  	snprintf(setsym, len, "%s%s", "__start_set_", name);
  	error = link_elf_lookup_symbol(lf, setsym, &sym);
  	if (error)
  		goto out;
  	link_elf_symbol_values(lf, sym, &symval);
  	if (symval.value == 0) {
  		error = ESRCH;
  		goto out;
  	}
  	start = (void **)symval.value;
  
  	/* get address of last entry */
  	snprintf(setsym, len, "%s%s", "__stop_set_", name);
  	error = link_elf_lookup_symbol(lf, setsym, &sym);
  	if (error)
  		goto out;
  	link_elf_symbol_values(lf, sym, &symval);
  	if (symval.value == 0) {
  		error = ESRCH;
  		goto out;
  	}
  	stop = (void **)symval.value;
  
  	/* and the number of entries */
  	count = stop - start;
  
  	/* and copy out */
  	if (startp)
  		*startp = start;
  	if (stopp)
  		*stopp = stop;
  	if (countp)
  		*countp = count;
  
  out:
  	free(setsym, M_LINKER);
  	return error;
  }
  
  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) {
  		error = callback(ef->ddbstrtab + symp->st_name, opaque);
  		if (error)
  		    return (error);
  	}
      }
      return (0);
  }
  
  #ifdef __ia64__
  /*
   * Each KLD has its own GP. The GP value for each load module is given by
   * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
   * don't have direct access to the ELF file structure. The link_elf_get_gp()
   * function returns the GP given a pointer to a generic linker file struct.
   */
  Elf_Addr
  link_elf_get_gp(linker_file_t lf)
  {
  	elf_file_t ef = (elf_file_t)lf;
  	return (Elf_Addr)ef->got;
  }
  #endif
  
  const Elf_Sym *
  elf_get_sym(linker_file_t lf, Elf_Word symidx)
  {
  	elf_file_t ef = (elf_file_t)lf;
  
  	if (symidx >= ef->nchains)
  		return (NULL);
  	return (ef->symtab + symidx);
  }
  
  const char *
  elf_get_symname(linker_file_t lf, Elf_Word symidx)
  {
  	elf_file_t ef = (elf_file_t)lf;
  	const Elf_Sym *sym;
  
  	if (symidx >= ef->nchains)
  		return (NULL);
  	sym = ef->symtab + symidx;
  	return (ef->strtab + sym->st_name);
  }
  
  /*
   * 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.
   */
  Elf_Addr
  elf_lookup(linker_file_t lf, Elf_Word symidx, int deps)
  {
  	elf_file_t ef = (elf_file_t)lf;
  	const Elf_Sym *sym;
  	const char *symbol;
  
  	/* Don't even try to lookup the symbol if the index is bogus. */
  	if (symidx >= ef->nchains)
  		return (0);
  
  	sym = ef->symtab + symidx;
  
  	/*
  	 * Don't do a full lookup when the symbol is local. It may even
  	 * fail because it may not be found through the hash table.
  	 */
  	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
  		/* Force lookup failure when we have an insanity. */
  		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
  			return (0);
  		return ((Elf_Addr)ef->address + sym->st_value);
  	}
  
  	/*
  	 * XXX we can avoid doing a hash table based lookup for global
  	 * symbols as well. This however is not always valid, so we'll
  	 * just do it the hard way for now. Performance tweaks can
  	 * always be added.
  	 */
  
  	symbol = ef->strtab + sym->st_name;
  
  	/* Force a lookup failure if the symbol name is bogus. */
  	if (*symbol == 0)
  		return (0);
  
  	return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
  }
  
  static void
  link_elf_reloc_local(linker_file_t lf)
  {
      const Elf_Rel *rellim;
      const Elf_Rel *rel;
      const Elf_Rela *relalim;
      const Elf_Rela *rela;
      elf_file_t ef = (elf_file_t)lf;
  
      /* Perform relocations without addend if there are any: */
      if ((rel = ef->rel) != NULL) {
  	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
  	while (rel < rellim) {
  	    elf_reloc_local(lf, rel, ELF_RELOC_REL);
  	    rel++;
  	}
      }
  
      /* Perform relocations with addend if there are any: */
      if ((rela = ef->rela) != NULL) {
  	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
  	while (rela < relalim) {
  	    elf_reloc_local(lf, rela, ELF_RELOC_RELA);
  	    rela++;
  	}
      }
  }
  