/* Postprocess module symbol versions
   *
   * Copyright 2003       Kai Germaschewski
   * Copyright 2002-2004  Rusty Russell, IBM Corporation

   * Copyright 2006-2008  Sam Ravnborg

   * Based in part on module-init-tools/depmod.c,file2alias
   *
   * This software may be used and distributed according to the terms
   * of the GNU General Public License, incorporated herein by reference.
   *
   * Usage: modpost vmlinux module1.o module2.o ...
   */

  #define _GNU_SOURCE
  #include <stdio.h>

  #include <ctype.h>

  #include <string.h>

  #include <limits.h>

  #include <stdbool.h>

  #include <errno.h>

  #include "modpost.h"

  #include "../../include/generated/autoconf.h"

  #include "../../include/linux/license.h"

  #include "../../include/linux/export.h"

  /* Are we using CONFIG_MODVERSIONS? */

  static int modversions = 0;

  /* Warn about undefined symbols? (do so if we have vmlinux) */

  static int have_vmlinux = 0;

  /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  static int all_versions = 0;

  /* If we are modposting external module set to 1 */
  static int external_module = 0;

  /* Warn about section mismatch in vmlinux if set to 1 */
  static int vmlinux_section_warnings = 1;

  /* Only warn about unresolved symbols */
  static int warn_unresolved = 0;

  /* How a symbol is exported */

  static int sec_mismatch_count = 0;
  static int sec_mismatch_verbose = 1;

  static int sec_mismatch_fatal = 0;

  /* ignore missing files */
  static int ignore_missing_files;

  enum export {
  	export_plain,      export_unused,     export_gpl,
  	export_unused_gpl, export_gpl_future, export_unknown
  };

  #define PRINTF __attribute__ ((format (printf, 1, 2)))
  
  PRINTF void fatal(const char *fmt, ...)

  {
  	va_list arglist;
  
  	fprintf(stderr, "FATAL: ");
  
  	va_start(arglist, fmt);
  	vfprintf(stderr, fmt, arglist);
  	va_end(arglist);
  
  	exit(1);
  }

  PRINTF void warn(const char *fmt, ...)

  {
  	va_list arglist;
  
  	fprintf(stderr, "WARNING: ");
  
  	va_start(arglist, fmt);
  	vfprintf(stderr, fmt, arglist);
  	va_end(arglist);
  }

  PRINTF void merror(const char *fmt, ...)

  {
  	va_list arglist;
  
  	fprintf(stderr, "ERROR: ");
  
  	va_start(arglist, fmt);
  	vfprintf(stderr, fmt, arglist);
  	va_end(arglist);
  }

  static inline bool strends(const char *str, const char *postfix)
  {
  	if (strlen(str) < strlen(postfix))
  		return false;
  
  	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
  }

  static int is_vmlinux(const char *modname)
  {
  	const char *myname;

  	myname = strrchr(modname, '/');
  	if (myname)

  		myname++;
  	else
  		myname = modname;

  	return (strcmp(myname, "vmlinux") == 0) ||
  	       (strcmp(myname, "vmlinux.o") == 0);

  }

  void *do_nofail(void *ptr, const char *expr)
  {

  	if (!ptr)

  		fatal("modpost: Memory allocation failure: %s.
  ", expr);

  	return ptr;
  }
  
  /* A list of all modules we processed */

  static struct module *modules;

  static struct module *find_module(char *modname)

  {
  	struct module *mod;
  
  	for (mod = modules; mod; mod = mod->next)
  		if (strcmp(mod->name, modname) == 0)
  			break;
  	return mod;
  }

  static struct module *new_module(const char *modname)

  {
  	struct module *mod;

  	char *p;

  	mod = NOFAIL(malloc(sizeof(*mod)));
  	memset(mod, 0, sizeof(*mod));
  	p = NOFAIL(strdup(modname));
  
  	/* strip trailing .o */

  	if (strends(p, ".o")) {
  		p[strlen(p) - 2] = '\0';
  		mod->is_dot_o = 1;
  	}

  
  	/* add to list */
  	mod->name = p;

  	mod->gpl_compatible = -1;

  	mod->next = modules;
  	modules = mod;
  
  	return mod;
  }
  
  /* A hash of all exported symbols,
   * struct symbol is also used for lists of unresolved symbols */
  
  #define SYMBOL_HASH_SIZE 1024
  
  struct symbol {
  	struct symbol *next;
  	struct module *module;
  	unsigned int crc;
  	int crc_valid;
  	unsigned int weak:1;

  	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
  	unsigned int kernel:1;     /* 1 if symbol is from kernel
  				    *  (only for external modules) **/

  	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers, or crc */

  	enum export  export;       /* Type of export */

  	char name[0];
  };
  
  static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
  
  /* This is based on the hash agorithm from gdbm, via tdb */
  static inline unsigned int tdb_hash(const char *name)
  {
  	unsigned value;	/* Used to compute the hash value.  */
  	unsigned   i;	/* Used to cycle through random values. */
  
  	/* Set the initial value from the key size. */

  	for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)

  		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
  
  	return (1103515243 * value + 12345);
  }

  /**
   * Allocate a new symbols for use in the hash of exported symbols or
   * the list of unresolved symbols per module
   **/
  static struct symbol *alloc_symbol(const char *name, unsigned int weak,
  				   struct symbol *next)

  {
  	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
  
  	memset(s, 0, sizeof(*s));
  	strcpy(s->name, name);
  	s->weak = weak;
  	s->next = next;
  	return s;
  }
  
  /* For the hash of exported symbols */

  static struct symbol *new_symbol(const char *name, struct module *module,
  				 enum export export)

  {
  	unsigned int hash;
  	struct symbol *new;
  
  	hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
  	new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
  	new->module = module;

  	new->export = export;

  	return new;

  }

  static struct symbol *find_symbol(const char *name)

  {
  	struct symbol *s;
  
  	/* For our purposes, .foo matches foo.  PPC64 needs this. */
  	if (name[0] == '.')
  		name++;

  	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {

  		if (strcmp(s->name, name) == 0)
  			return s;
  	}
  	return NULL;
  }

  static const struct {

  	const char *str;
  	enum export export;
  } export_list[] = {
  	{ .str = "EXPORT_SYMBOL",            .export = export_plain },

  	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },

  	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },

  	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },

  	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
  	{ .str = "(unknown)",                .export = export_unknown },
  };
  
  
  static const char *export_str(enum export ex)
  {
  	return export_list[ex].str;
  }

  static enum export export_no(const char *s)

  {
  	int i;

  	if (!s)
  		return export_unknown;

  	for (i = 0; export_list[i].export != export_unknown; i++) {
  		if (strcmp(export_list[i].str, s) == 0)
  			return export_list[i].export;
  	}
  	return export_unknown;
  }

  static const char *sec_name(struct elf_info *elf, int secindex);
  
  #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
  
  static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
  {
  	const char *secname = sec_name(elf, sec);
  
  	if (strstarts(secname, "___ksymtab+"))
  		return export_plain;
  	else if (strstarts(secname, "___ksymtab_unused+"))
  		return export_unused;
  	else if (strstarts(secname, "___ksymtab_gpl+"))
  		return export_gpl;
  	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
  		return export_unused_gpl;
  	else if (strstarts(secname, "___ksymtab_gpl_future+"))
  		return export_gpl_future;
  	else
  		return export_unknown;
  }

  static enum export export_from_sec(struct elf_info *elf, unsigned int sec)

  {
  	if (sec == elf->export_sec)
  		return export_plain;

  	else if (sec == elf->export_unused_sec)
  		return export_unused;

  	else if (sec == elf->export_gpl_sec)
  		return export_gpl;

  	else if (sec == elf->export_unused_gpl_sec)
  		return export_unused_gpl;

  	else if (sec == elf->export_gpl_future_sec)
  		return export_gpl_future;
  	else
  		return export_unknown;
  }

  /**
   * Add an exported symbol - it may have already been added without a
   * CRC, in this case just update the CRC
   **/

  static struct symbol *sym_add_exported(const char *name, struct module *mod,
  				       enum export export)

  {
  	struct symbol *s = find_symbol(name);
  
  	if (!s) {

  		s = new_symbol(name, mod, export);

  	} else {
  		if (!s->preloaded) {

  			warn("%s: '%s' exported twice. Previous export "

  			     "was in %s%s
  ", mod->name, name,
  			     s->module->name,
  			     is_vmlinux(s->module->name) ?"":".ko");

  		} else {

  			/* In case Module.symvers was out of date */

  			s->module = mod;

  		}

  	}

  	s->preloaded = 0;

  	s->vmlinux   = is_vmlinux(mod->name);
  	s->kernel    = 0;

  	s->export    = export;

  	return s;
  }
  
  static void sym_update_crc(const char *name, struct module *mod,

  			   unsigned int crc, enum export export)

  {
  	struct symbol *s = find_symbol(name);

  	if (!s) {

  		s = new_symbol(name, mod, export);

  		/* Don't complain when we find it later. */
  		s->preloaded = 1;
  	}

  	s->crc = crc;
  	s->crc_valid = 1;

  }

  void *grab_file(const char *filename, unsigned long *size)

  {
  	struct stat st;

  	void *map = MAP_FAILED;

  	int fd;
  
  	fd = open(filename, O_RDONLY);

  	if (fd < 0)

  		return NULL;

  	if (fstat(fd, &st))
  		goto failed;

  
  	*size = st.st_size;
  	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);

  failed:
  	close(fd);

  	if (map == MAP_FAILED)
  		return NULL;
  	return map;
  }

  /**
    * Return a copy of the next line in a mmap'ed file.
    * spaces in the beginning of the line is trimmed away.
    * Return a pointer to a static buffer.
    **/

  char *get_next_line(unsigned long *pos, void *file, unsigned long size)

  {
  	static char line[4096];
  	int skip = 1;
  	size_t len = 0;
  	signed char *p = (signed char *)file + *pos;
  	char *s = line;

  	for (; *pos < size ; (*pos)++) {

  		if (skip && isspace(*p)) {
  			p++;
  			continue;
  		}
  		skip = 0;
  		if (*p != '
  ' && (*pos < size)) {
  			len++;
  			*s++ = *p++;
  			if (len > 4095)
  				break; /* Too long, stop */
  		} else {
  			/* End of string */
  			*s = '\0';
  			return line;
  		}
  	}
  	/* End of buffer */
  	return NULL;
  }

  void release_file(void *file, unsigned long size)

  {
  	munmap(file, size);
  }

  static int parse_elf(struct elf_info *info, const char *filename)

  {
  	unsigned int i;

  	Elf_Ehdr *hdr;

  	Elf_Shdr *sechdrs;
  	Elf_Sym  *sym;

  	const char *secstrings;
  	unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;

  
  	hdr = grab_file(filename, &info->size);
  	if (!hdr) {

  		if (ignore_missing_files) {
  			fprintf(stderr, "%s: %s (ignored)
  ", filename,
  				strerror(errno));
  			return 0;
  		}

  		perror(filename);

  		exit(1);

  	}
  	info->hdr = hdr;

  	if (info->size < sizeof(*hdr)) {
  		/* file too small, assume this is an empty .o file */
  		return 0;
  	}
  	/* Is this a valid ELF file? */
  	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
  	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
  	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
  	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
  		/* Not an ELF file - silently ignore it */
  		return 0;
  	}

  	/* Fix endianness in ELF header */

  	hdr->e_type      = TO_NATIVE(hdr->e_type);
  	hdr->e_machine   = TO_NATIVE(hdr->e_machine);
  	hdr->e_version   = TO_NATIVE(hdr->e_version);
  	hdr->e_entry     = TO_NATIVE(hdr->e_entry);
  	hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
  	hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
  	hdr->e_flags     = TO_NATIVE(hdr->e_flags);
  	hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
  	hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
  	hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
  	hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
  	hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
  	hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);

  	sechdrs = (void *)hdr + hdr->e_shoff;
  	info->sechdrs = sechdrs;

  	/* Check if file offset is correct */
  	if (hdr->e_shoff > info->size) {

  		fatal("section header offset=%lu in file '%s' is bigger than "
  		      "filesize=%lu
  ", (unsigned long)hdr->e_shoff,
  		      filename, info->size);

  		return 0;
  	}

  	if (hdr->e_shnum == SHN_UNDEF) {

  		/*
  		 * There are more than 64k sections,
  		 * read count from .sh_size.

  		 */
  		info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
  	}
  	else {
  		info->num_sections = hdr->e_shnum;
  	}
  	if (hdr->e_shstrndx == SHN_XINDEX) {

  		info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);

  	}
  	else {
  		info->secindex_strings = hdr->e_shstrndx;
  	}

  	/* Fix endianness in section headers */

  	for (i = 0; i < info->num_sections; i++) {

  		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
  		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
  		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
  		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
  		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
  		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
  		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
  		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
  		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
  		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);

  	}
  	/* Find symbol table. */

  	secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
  	for (i = 1; i < info->num_sections; i++) {

  		const char *secname;

  		int nobits = sechdrs[i].sh_type == SHT_NOBITS;

  		if (!nobits && sechdrs[i].sh_offset > info->size) {

  			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
  			      "sizeof(*hrd)=%zu
  ", filename,
  			      (unsigned long)sechdrs[i].sh_offset,
  			      sizeof(*hdr));

  			return 0;
  		}

  		secname = secstrings + sechdrs[i].sh_name;
  		if (strcmp(secname, ".modinfo") == 0) {

  			if (nobits)
  				fatal("%s has NOBITS .modinfo
  ", filename);

  			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
  			info->modinfo_len = sechdrs[i].sh_size;

  		} else if (strcmp(secname, "__ksymtab") == 0)
  			info->export_sec = i;

  		else if (strcmp(secname, "__ksymtab_unused") == 0)
  			info->export_unused_sec = i;

  		else if (strcmp(secname, "__ksymtab_gpl") == 0)
  			info->export_gpl_sec = i;

  		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
  			info->export_unused_gpl_sec = i;

  		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
  			info->export_gpl_future_sec = i;

  		if (sechdrs[i].sh_type == SHT_SYMTAB) {
  			unsigned int sh_link_idx;
  			symtab_idx = i;
  			info->symtab_start = (void *)hdr +
  			    sechdrs[i].sh_offset;
  			info->symtab_stop  = (void *)hdr +
  			    sechdrs[i].sh_offset + sechdrs[i].sh_size;

  			sh_link_idx = sechdrs[i].sh_link;

  			info->strtab       = (void *)hdr +
  			    sechdrs[sh_link_idx].sh_offset;
  		}

  		/* 32bit section no. table? ("more than 64k sections") */
  		if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
  			symtab_shndx_idx = i;
  			info->symtab_shndx_start = (void *)hdr +
  			    sechdrs[i].sh_offset;
  			info->symtab_shndx_stop  = (void *)hdr +
  			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
  		}

  	}

  	if (!info->symtab_start)

  		fatal("%s has no symtab?
  ", filename);

  	/* Fix endianness in symbols */
  	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
  		sym->st_shndx = TO_NATIVE(sym->st_shndx);
  		sym->st_name  = TO_NATIVE(sym->st_name);
  		sym->st_value = TO_NATIVE(sym->st_value);
  		sym->st_size  = TO_NATIVE(sym->st_size);
  	}

  
  	if (symtab_shndx_idx != ~0U) {
  		Elf32_Word *p;

  		if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)

  			fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u
  ",

  			      filename, sechdrs[symtab_shndx_idx].sh_link,

  			      symtab_idx);
  		/* Fix endianness */
  		for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
  		     p++)
  			*p = TO_NATIVE(*p);
  	}

  	return 1;

  }

  static void parse_elf_finish(struct elf_info *info)

  {
  	release_file(info->hdr, info->size);
  }

  static int ignore_undef_symbol(struct elf_info *info, const char *symname)
  {
  	/* ignore __this_module, it will be resolved shortly */

  	if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)

  		return 1;
  	/* ignore global offset table */
  	if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
  		return 1;
  	if (info->hdr->e_machine == EM_PPC)
  		/* Special register function linked on all modules during final link of .ko */
  		if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
  		    strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
  		    strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||

  		    strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
  		    strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
  		    strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)

  			return 1;

  	if (info->hdr->e_machine == EM_PPC64)
  		/* Special register function linked on all modules during final link of .ko */
  		if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||

  		    strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
  		    strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||

  		    strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
  		    strcmp(symname, ".TOC.") == 0)

  			return 1;

  	/* Do not ignore this symbol */
  	return 0;
  }

  #define CRC_PFX     VMLINUX_SYMBOL_STR(__crc_)
  #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)

  static void handle_modversions(struct module *mod, struct elf_info *info,
  			       Elf_Sym *sym, const char *symname)

  {
  	unsigned int crc;

  	enum export export;

  	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
  	    strncmp(symname, "__ksymtab", 9) == 0)

  		export = export_from_secname(info, get_secindex(info, sym));
  	else
  		export = export_from_sec(info, get_secindex(info, sym));

  	/* CRC'd symbol */
  	if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
  		crc = (unsigned int) sym->st_value;
  		sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
  				export);
  	}

  	switch (sym->st_shndx) {
  	case SHN_COMMON:

  		if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
  			/* Should warn here, but modpost runs before the linker */
  		} else
  			warn("\"%s\" [%s] is COMMON symbol
  ", symname, mod->name);

  		break;

  	case SHN_UNDEF:
  		/* undefined symbol */
  		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
  		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
  			break;

  		if (ignore_undef_symbol(info, symname))

  			break;

  /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
  #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
  /* add compatibility with older glibc */
  #ifndef STT_SPARC_REGISTER
  #define STT_SPARC_REGISTER STT_REGISTER
  #endif

  		if (info->hdr->e_machine == EM_SPARC ||
  		    info->hdr->e_machine == EM_SPARCV9) {
  			/* Ignore register directives. */

  			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)

  				break;

  			if (symname[0] == '.') {
  				char *munged = strdup(symname);
  				munged[0] = '_';
  				munged[1] = toupper(munged[1]);
  				symname = munged;
  			}

  		}
  #endif

  #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
  		if (symname[0] != '_')
  			break;
  		else
  			symname++;
  #endif
  		mod->unres = alloc_symbol(symname,
  					  ELF_ST_BIND(sym->st_info) == STB_WEAK,
  					  mod->unres);

  		break;
  	default:
  		/* All exported symbols */

  		if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {

  			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
  					export);

  		}

  		if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)

  			mod->has_init = 1;

  		if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)

  			mod->has_cleanup = 1;
  		break;
  	}
  }

  /**
   * Parse tag=value strings from .modinfo section
   **/

  static char *next_string(char *string, unsigned long *secsize)
  {
  	/* Skip non-zero chars */
  	while (string[0]) {
  		string++;
  		if ((*secsize)-- <= 1)
  			return NULL;
  	}
  
  	/* Skip any zero padding. */
  	while (!string[0]) {
  		string++;
  		if ((*secsize)-- <= 1)
  			return NULL;
  	}
  	return string;
  }

  static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
  			      const char *tag, char *info)

  {
  	char *p;
  	unsigned int taglen = strlen(tag);
  	unsigned long size = modinfo_len;

  	if (info) {
  		size -= info - (char *)modinfo;
  		modinfo = next_string(info, &size);
  	}

  	for (p = modinfo; p; p = next_string(p, &size)) {
  		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
  			return p + taglen + 1;
  	}
  	return NULL;
  }

  static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
  			 const char *tag)
  
  {
  	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
  }

  /**

   * Test if string s ends in string sub
   * return 0 if match
   **/
  static int strrcmp(const char *s, const char *sub)
  {

  	int slen, sublen;

  	if (!s || !sub)
  		return 1;

  	slen = strlen(s);

  	sublen = strlen(sub);

  	if ((slen == 0) || (sublen == 0))
  		return 1;

  	if (sublen > slen)
  		return 1;

  	return memcmp(s + slen - sublen, sub, sublen);

  }

  static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
  {

  	if (sym)
  		return elf->strtab + sym->st_name;
  	else

  		return "(unknown)";

  }

  static const char *sec_name(struct elf_info *elf, int secindex)

  {
  	Elf_Shdr *sechdrs = elf->sechdrs;
  	return (void *)elf->hdr +

  		elf->sechdrs[elf->secindex_strings].sh_offset +
  		sechdrs[secindex].sh_name;

  }
  
  static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
  {
  	return (void *)elf->hdr +

  		elf->sechdrs[elf->secindex_strings].sh_offset +
  		sechdr->sh_name;

  }

  /* The pattern is an array of simple patterns.
   * "foo" will match an exact string equal to "foo"

   * "*foo" will match a string that ends with "foo"

   * "foo*" will match a string that begins with "foo"

   * "*foo*" will match a string that contains "foo"

   */

  static int match(const char *sym, const char * const pat[])

  {
  	const char *p;
  	while (*pat) {
  		p = *pat++;
  		const char *endp = p + strlen(p) - 1;

  		/* "*foo*" */
  		if (*p == '*' && *endp == '*') {
  			char *here, *bare = strndup(p + 1, strlen(p) - 2);
  
  			here = strstr(sym, bare);
  			free(bare);
  			if (here != NULL)
  				return 1;
  		}

  		/* "*foo" */

  		else if (*p == '*') {

  			if (strrcmp(sym, p + 1) == 0)
  				return 1;
  		}

  		/* "foo*" */

  		else if (*endp == '*') {

  			if (strncmp(sym, p, strlen(p) - 1) == 0)
  				return 1;
  		}

  		/* no wildcards */
  		else {
  			if (strcmp(p, sym) == 0)
  				return 1;
  		}
  	}
  	/* no match */
  	return 0;
  }

  /* sections that we do not want to do full section mismatch check on */

  static const char *const section_white_list[] =

  {
  	".comment*",
  	".debug*",

  	".cranges",		/* sh64 */

  	".zdebug*",		/* Compressed debug sections. */

  	".GCC-command-line",	/* mn10300 */

  	".GCC.command.line",	/* record-gcc-switches, non mn10300 */

  	".mdebug*",        /* alpha, score, mips etc. */
  	".pdr",            /* alpha, score, mips etc. */
  	".stab*",
  	".note*",
  	".got*",
  	".toc*",

  	".xt.prop",				 /* xtensa */
  	".xt.lit",         /* xtensa */

  	".arcextmap*",			/* arc */
  	".gnu.linkonce.arcext*",	/* arc : modules */

  	".cmem*",			/* EZchip */
  	".fmt_slot*",			/* EZchip */

  	".gnu.lto*",

  	NULL
  };

  /*

   * This is used to find sections missing the SHF_ALLOC flag.

   * The cause of this is often a section specified in assembler

   * without "ax" / "aw".

   */

  static void check_section(const char *modname, struct elf_info *elf,

  			  Elf_Shdr *sechdr)

  {

  	const char *sec = sech_name(elf, sechdr);
  
  	if (sechdr->sh_type == SHT_PROGBITS &&
  	    !(sechdr->sh_flags & SHF_ALLOC) &&
  	    !match(sec, section_white_list)) {
  		warn("%s (%s): unexpected non-allocatable section.
  "
  		     "Did you forget to use \"ax\"/\"aw\" in a .S file?
  "
  		     "Note that for example <linux/init.h> contains
  "
  		     "section definitions for use in .S files.
  
  ",
  		     modname, sec);

  	}

  }

  #define ALL_INIT_DATA_SECTIONS \

  	".init.setup", ".init.rodata", ".meminit.rodata", \
  	".init.data", ".meminit.data"

  #define ALL_EXIT_DATA_SECTIONS \

  	".exit.data", ".memexit.data"

  #define ALL_INIT_TEXT_SECTIONS \

  	".init.text", ".meminit.text"

  #define ALL_EXIT_TEXT_SECTIONS \

  	".exit.text", ".memexit.text"

  #define ALL_PCI_INIT_SECTIONS	\

  	".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
  	".pci_fixup_enable", ".pci_fixup_resume", \
  	".pci_fixup_resume_early", ".pci_fixup_suspend"

  #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
  #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS

  
  #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
  #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS

  #define DATA_SECTIONS ".data", ".data.rel"

  #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
  		".kprobes.text"

  #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \

  		".fixup", ".entry.text", ".exception.text", ".text.*", \
  		".coldtext"

  #define INIT_SECTIONS      ".init.*"

  #define MEM_INIT_SECTIONS  ".meminit.*"

  #define EXIT_SECTIONS      ".exit.*"

  #define MEM_EXIT_SECTIONS  ".memexit.*"

  #define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
  		TEXT_SECTIONS, OTHER_TEXT_SECTIONS

  /* init data sections */

  static const char *const init_data_sections[] =
  	{ ALL_INIT_DATA_SECTIONS, NULL };

  
  /* all init sections */

  static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };

  
  /* All init and exit sections (code + data) */

  static const char *const init_exit_sections[] =

  	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };

  /* all text sections */
  static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };

  /* data section */

  static const char *const data_sections[] = { DATA_SECTIONS, NULL };

  
  /* symbols in .data that may refer to init/exit sections */

  #define DEFAULT_SYMBOL_WHITE_LIST					\
  	"*driver",							\
  	"*_template", /* scsi uses *_template a lot */			\
  	"*_timer",    /* arm uses ops structures named _timer a lot */	\
  	"*_sht",      /* scsi also used *_sht to some extent */		\
  	"*_ops",							\
  	"*_probe",							\
  	"*_probe_one",							\
  	"*_console"

  static const char *const head_sections[] = { ".head.text*", NULL };
  static const char *const linker_symbols[] =

  	{ "__init_begin", "_sinittext", "_einittext", NULL };

  static const char *const optim_symbols[] = { "*.constprop.*", NULL };

  enum mismatch {

  	TEXT_TO_ANY_INIT,
  	DATA_TO_ANY_INIT,
  	TEXT_TO_ANY_EXIT,
  	DATA_TO_ANY_EXIT,
  	XXXINIT_TO_SOME_INIT,
  	XXXEXIT_TO_SOME_EXIT,
  	ANY_INIT_TO_ANY_EXIT,
  	ANY_EXIT_TO_ANY_INIT,

  	EXPORT_TO_INIT_EXIT,

  	EXTABLE_TO_NON_TEXT,

  };

  /**
   * Describe how to match sections on different criterias:
   *
   * @fromsec: Array of sections to be matched.
   *
   * @bad_tosec: Relocations applied to a section in @fromsec to a section in
   * this array is forbidden (black-list).  Can be empty.
   *
   * @good_tosec: Relocations applied to a section in @fromsec must be
   * targetting sections in this array (white-list).  Can be empty.
   *
   * @mismatch: Type of mismatch.
   *
   * @symbol_white_list: Do not match a relocation to a symbol in this list
   * even if it is targetting a section in @bad_to_sec.
   *
   * @handler: Specific handler to call when a match is found.  If NULL,
   * default_mismatch_handler() will be called.
   *
   */

  struct sectioncheck {
  	const char *fromsec[20];

  	const char *bad_tosec[20];
  	const char *good_tosec[20];

  	enum mismatch mismatch;

  	const char *symbol_white_list[20];

  	void (*handler)(const char *modname, struct elf_info *elf,
  			const struct sectioncheck* const mismatch,
  			Elf_Rela *r, Elf_Sym *sym, const char *fromsec);

  };

  static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
  				     const struct sectioncheck* const mismatch,
  				     Elf_Rela *r, Elf_Sym *sym,
  				     const char *fromsec);

  static const struct sectioncheck sectioncheck[] = {

  /* Do not reference init/exit code/data from
   * normal code and data
   */
  {

  	.fromsec = { TEXT_SECTIONS, NULL },

  	.bad_tosec = { ALL_INIT_SECTIONS, NULL },

  	.mismatch = TEXT_TO_ANY_INIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },
  {
  	.fromsec = { DATA_SECTIONS, NULL },

  	.bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },

  	.mismatch = DATA_TO_ANY_INIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },
  {

  	.fromsec = { DATA_SECTIONS, NULL },

  	.bad_tosec = { INIT_SECTIONS, NULL },

  	.mismatch = DATA_TO_ANY_INIT,
  	.symbol_white_list = {
  		"*_template", "*_timer", "*_sht", "*_ops",
  		"*_probe", "*_probe_one", "*_console", NULL
  	},
  },
  {

  	.fromsec = { TEXT_SECTIONS, NULL },

  	.bad_tosec = { ALL_EXIT_SECTIONS, NULL },

  	.mismatch = TEXT_TO_ANY_EXIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },
  {
  	.fromsec = { DATA_SECTIONS, NULL },

  	.bad_tosec = { ALL_EXIT_SECTIONS, NULL },

  	.mismatch = DATA_TO_ANY_EXIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },

  /* Do not reference init code/data from meminit code/data */

  {

  	.fromsec = { ALL_XXXINIT_SECTIONS, NULL },

  	.bad_tosec = { INIT_SECTIONS, NULL },

  	.mismatch = XXXINIT_TO_SOME_INIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },

  /* Do not reference exit code/data from memexit code/data */

  {

  	.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },

  	.bad_tosec = { EXIT_SECTIONS, NULL },

  	.mismatch = XXXEXIT_TO_SOME_EXIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },
  /* Do not use exit code/data from init code */
  {

  	.fromsec = { ALL_INIT_SECTIONS, NULL },

  	.bad_tosec = { ALL_EXIT_SECTIONS, NULL },

  	.mismatch = ANY_INIT_TO_ANY_EXIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },
  /* Do not use init code/data from exit code */
  {

  	.fromsec = { ALL_EXIT_SECTIONS, NULL },

  	.bad_tosec = { ALL_INIT_SECTIONS, NULL },

  	.mismatch = ANY_EXIT_TO_ANY_INIT,

  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },

  {
  	.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },

  	.bad_tosec = { INIT_SECTIONS, NULL },

  	.mismatch = ANY_INIT_TO_ANY_EXIT,
  	.symbol_white_list = { NULL },
  },

  /* Do not export init/exit functions or data */
  {
  	.fromsec = { "__ksymtab*", NULL },

  	.bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },

  	.mismatch = EXPORT_TO_INIT_EXIT,
  	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },

  },
  {
  	.fromsec = { "__ex_table", NULL },
  	/* If you're adding any new black-listed sections in here, consider
  	 * adding a special 'printer' for them in scripts/check_extable.
  	 */
  	.bad_tosec = { ".altinstr_replacement", NULL },
  	.good_tosec = {ALL_TEXT_SECTIONS , NULL},
  	.mismatch = EXTABLE_TO_NON_TEXT,
  	.handler = extable_mismatch_handler,

  }
  };

  static const struct sectioncheck *section_mismatch(
  		const char *fromsec, const char *tosec)

  {
  	int i;
  	int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
  	const struct sectioncheck *check = &sectioncheck[0];

  	/*
  	 * The target section could be the SHT_NUL section when we're
  	 * handling relocations to un-resolved symbols, trying to match it
  	 * doesn't make much sense and causes build failures on parisc and
  	 * mn10300 architectures.
  	 */
  	if (*tosec == '\0')
  		return NULL;

  	for (i = 0; i < elems; i++) {

  		if (match(fromsec, check->fromsec)) {
  			if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
  				return check;
  			if (check->good_tosec[0] && !match(tosec, check->good_tosec))
  				return check;
  		}

  		check++;
  	}

  	return NULL;

  }

  /**
   * Whitelist to allow certain references to pass with no warning.

   *

   * Pattern 1:
   *   If a module parameter is declared __initdata and permissions=0
   *   then this is legal despite the warning generated.
   *   We cannot see value of permissions here, so just ignore
   *   this pattern.
   *   The pattern is identified by:
   *   tosec   = .init.data

   *   fromsec = .data*

   *   atsym   =__param*

   *

   * Pattern 1a:
   *   module_param_call() ops can refer to __init set function if permissions=0
   *   The pattern is identified by:
   *   tosec   = .init.text
   *   fromsec = .data*
   *   atsym   = __param_ops_*
   *

   * Pattern 2:

   *   Many drivers utilise a *driver container with references to

   *   add, remove, probe functions etc.

   *   the pattern is identified by:

   *   tosec   = init or exit section
   *   fromsec = data section

   *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
   *           *probe_one, *_console, *_timer

   *
   * Pattern 3:

   *   Whitelist all references from .head.text to any init section

   *

   * Pattern 4:

   *   Some symbols belong to init section but still it is ok to reference
   *   these from non-init sections as these symbols don't have any memory
   *   allocated for them and symbol address and value are same. So even
   *   if init section is freed, its ok to reference those symbols.
   *   For ex. symbols marking the init section boundaries.
   *   This pattern is identified by
   *   refsymname = __init_begin, _sinittext, _einittext

   *

   * Pattern 5:
   *   GCC may optimize static inlines when fed constant arg(s) resulting
   *   in functions like cpumask_empty() -- generating an associated symbol
   *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
   *   is passed in comes from __init, like say nmi_ipi_mask, we get a
   *   meaningless section warning.  May need to add isra symbols too...
   *   This pattern is identified by
   *   tosec   = init section
   *   fromsec = text section
   *   refsymname = *.constprop.*
   *

   **/

  static int secref_whitelist(const struct sectioncheck *mismatch,
  			    const char *fromsec, const char *fromsym,

  			    const char *tosec, const char *tosym)

  {

  	/* Check for pattern 1 */

  	if (match(tosec, init_data_sections) &&
  	    match(fromsec, data_sections) &&

  	    (strncmp(fromsym, "__param", strlen("__param")) == 0))
  		return 0;

  	/* Check for pattern 1a */
  	if (strcmp(tosec, ".init.text") == 0 &&
  	    match(fromsec, data_sections) &&
  	    (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
  		return 0;

  	/* Check for pattern 2 */

  	if (match(tosec, init_exit_sections) &&
  	    match(fromsec, data_sections) &&

  	    match(fromsym, mismatch->symbol_white_list))

  		return 0;

  	/* Check for pattern 3 */

  	if (match(fromsec, head_sections) &&
  	    match(tosec, init_sections))

  		return 0;

  	/* Check for pattern 4 */

  	if (match(tosym, linker_symbols))
  		return 0;

  	/* Check for pattern 5 */
  	if (match(fromsec, text_sections) &&
  	    match(tosec, init_sections) &&
  	    match(fromsym, optim_symbols))
  		return 0;

  	return 1;

  }
  
  /**

   * Find symbol based on relocation record info.
   * In some cases the symbol supplied is a valid symbol so
   * return refsym. If st_name != 0 we assume this is a valid symbol.
   * In other cases the symbol needs to be looked up in the symbol table
   * based on section and address.
   *  **/

  static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,

  				Elf_Sym *relsym)
  {
  	Elf_Sym *sym;

  	Elf_Sym *near = NULL;
  	Elf64_Sword distance = 20;
  	Elf64_Sword d;

  	unsigned int relsym_secindex;

  
  	if (relsym->st_name != 0)
  		return relsym;

  
  	relsym_secindex = get_secindex(elf, relsym);

  	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {

  		if (get_secindex(elf, sym) != relsym_secindex)

  			continue;

  		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
  			continue;

  		if (sym->st_value == addr)
  			return sym;

  		/* Find a symbol nearby - addr are maybe negative */
  		d = sym->st_value - addr;
  		if (d < 0)
  			d = addr - sym->st_value;
  		if (d < distance) {
  			distance = d;
  			near = sym;
  		}

  	}

  	/* We need a close match */
  	if (distance < 20)
  		return near;
  	else
  		return NULL;

  }

  static inline int is_arm_mapping_symbol(const char *str)
  {

  	return str[0] == '$' && strchr("axtd", str[1])

  	       && (str[2] == '\0' || str[2] == '.');
  }
  
  /*
   * If there's no name there, ignore it; likewise, ignore it if it's
   * one of the magic symbols emitted used by current ARM tools.
   *
   * Otherwise if find_symbols_between() returns those symbols, they'll
   * fail the whitelist tests and cause lots of false alarms ... fixable
   * only by merging __exit and __init sections into __text, bloating
   * the kernel (which is especially evil on embedded platforms).
   */
  static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
  {
  	const char *name = elf->strtab + sym->st_name;
  
  	if (!name || !strlen(name))
  		return 0;
  	return !is_arm_mapping_symbol(name);
  }

  /*

   * Find symbols before or equal addr and after addr - in the section sec.
   * If we find two symbols with equal offset prefer one with a valid name.
   * The ELF format may have a better way to detect what type of symbol
   * it is, but this works for now.

   **/

  static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
  				 const char *sec)

  {
  	Elf_Sym *sym;

  	Elf_Sym *near = NULL;

  	Elf_Addr distance = ~0;

  	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
  		const char *symsec;

  		if (is_shndx_special(sym->st_shndx))

  			continue;

  		symsec = sec_name(elf, get_secindex(elf, sym));

  		if (strcmp(symsec, sec) != 0)
  			continue;

  		if (!is_valid_name(elf, sym))
  			continue;

  		if (sym->st_value <= addr) {

  			if ((addr - sym->st_value) < distance) {
  				distance = addr - sym->st_value;
  				near = sym;
  			} else if ((addr - sym->st_value) == distance) {
  				near = sym;

  			}

  		}
  	}

  	return near;

  }

  /*

   * Convert a section name to the function/data attribute
   * .init.text => __init

   * .memexitconst => __memconst
   * etc.

   *
   * The memory of returned value has been allocated on a heap. The user of this
   * method should free it after usage.

  */
  static char *sec2annotation(const char *s)
  {
  	if (match(s, init_exit_sections)) {
  		char *p = malloc(20);
  		char *r = p;
  
  		*p++ = '_';
  		*p++ = '_';
  		if (*s == '.')
  			s++;
  		while (*s && *s != '.')
  			*p++ = *s++;
  		*p = '\0';
  		if (*s == '.')
  			s++;
  		if (strstr(s, "rodata") != NULL)
  			strcat(p, "const ");
  		else if (strstr(s, "data") != NULL)
  			strcat(p, "data ");
  		else
  			strcat(p, " ");

  		return r;

  	} else {

  		return strdup("");

  	}
  }
  
  static int is_function(Elf_Sym *sym)
  {
  	if (sym)
  		return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
  	else

  		return -1;

  }

  static void print_section_list(const char * const list[20])
  {
  	const char *const *s = list;
  
  	while (*s) {
  		fprintf(stderr, "%s", *s);
  		s++;
  		if (*s)
  			fprintf(stderr, ", ");
  	}
  	fprintf(stderr, "
  ");
  }

  static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
  {
  	switch (is_func) {
  	case 0:	*name = "variable"; *name_p = ""; break;
  	case 1:	*name = "function"; *name_p = "()"; break;
  	default: *name = "(unknown reference)"; *name_p = ""; break;
  	}
  }

  /*

   * Print a warning about a section mismatch.
   * Try to find symbols near it so user can find it.

   * Check whitelist before warning - it may be a false positive.

   */

  static void report_sec_mismatch(const char *modname,
  				const struct sectioncheck *mismatch,

  				const char *fromsec,
  				unsigned long long fromaddr,
  				const char *fromsym,
  				int from_is_func,
  				const char *tosec, const char *tosym,
  				int to_is_func)

  {
  	const char *from, *from_p;
  	const char *to, *to_p;

  	char *prl_from;
  	char *prl_to;

  	sec_mismatch_count++;
  	if (!sec_mismatch_verbose)
  		return;

  	get_pretty_name(from_is_func, &from, &from_p);
  	get_pretty_name(to_is_func, &to, &to_p);

  	warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
  	     "to the %s %s:%s%s
  ",
  	     modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
  	     tosym, to_p);

  	switch (mismatch->mismatch) {

  	case TEXT_TO_ANY_INIT:

  		prl_from = sec2annotation(fromsec);
  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,

  		"The function %s%s() references
  "

  		"the %s %s%s%s.
  "
  		"This is often because %s lacks a %s
  "
  		"annotation or the annotation of %s is wrong.
  ",

  		prl_from, fromsym,
  		to, prl_to, tosym, to_p,
  		fromsym, prl_to, tosym);
  		free(prl_from);
  		free(prl_to);

  		break;

  	case DATA_TO_ANY_INIT: {

  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The variable %s references
  "
  		"the %s %s%s%s
  "
  		"If the reference is valid then annotate the
  "

  		"variable with __init* or __refdata (see linux/init.h) "

  		"or name the variable:
  ",

  		fromsym, to, prl_to, tosym, to_p);

  		print_section_list(mismatch->symbol_white_list);

  		free(prl_to);

  		break;

  	}

  	case TEXT_TO_ANY_EXIT:

  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The function %s() references a %s in an exit section.
  "
  		"Often the %s %s%s has valid usage outside the exit section
  "
  		"and the fix is to remove the %sannotation of %s.
  ",

  		fromsym, to, to, tosym, to_p, prl_to, tosym);
  		free(prl_to);

  		break;

  	case DATA_TO_ANY_EXIT: {

  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The variable %s references
  "
  		"the %s %s%s%s
  "
  		"If the reference is valid then annotate the
  "
  		"variable with __exit* (see linux/init.h) or "
  		"name the variable:
  ",

  		fromsym, to, prl_to, tosym, to_p);

  		print_section_list(mismatch->symbol_white_list);

  		free(prl_to);

  		break;
  	}

  	case XXXINIT_TO_SOME_INIT:
  	case XXXEXIT_TO_SOME_EXIT:

  		prl_from = sec2annotation(fromsec);
  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The %s %s%s%s references
  "
  		"a %s %s%s%s.
  "
  		"If %s is only used by %s then
  "
  		"annotate %s with a matching annotation.
  ",

  		from, prl_from, fromsym, from_p,
  		to, prl_to, tosym, to_p,

  		tosym, fromsym, tosym);

  		free(prl_from);
  		free(prl_to);

  		break;

  	case ANY_INIT_TO_ANY_EXIT:

  		prl_from = sec2annotation(fromsec);
  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The %s %s%s%s references
  "
  		"a %s %s%s%s.
  "
  		"This is often seen when error handling "
  		"in the init function
  "
  		"uses functionality in the exit path.
  "
  		"The fix is often to remove the %sannotation of
  "
  		"%s%s so it may be used outside an exit section.
  ",

  		from, prl_from, fromsym, from_p,
  		to, prl_to, tosym, to_p,

  		prl_to, tosym, to_p);

  		free(prl_from);
  		free(prl_to);

  		break;

  	case ANY_EXIT_TO_ANY_INIT:

  		prl_from = sec2annotation(fromsec);
  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The %s %s%s%s references
  "
  		"a %s %s%s%s.
  "
  		"This is often seen when error handling "
  		"in the exit function
  "
  		"uses functionality in the init path.
  "
  		"The fix is often to remove the %sannotation of
  "
  		"%s%s so it may be used outside an init section.
  ",

  		from, prl_from, fromsym, from_p,
  		to, prl_to, tosym, to_p,
  		prl_to, tosym, to_p);
  		free(prl_from);
  		free(prl_to);

  		break;
  	case EXPORT_TO_INIT_EXIT:

  		prl_to = sec2annotation(tosec);

  		fprintf(stderr,
  		"The symbol %s is exported and annotated %s
  "
  		"Fix this by removing the %sannotation of %s "
  		"or drop the export.
  ",

  		tosym, prl_to, prl_to, tosym);
  		free(prl_to);

  		break;

  	case EXTABLE_TO_NON_TEXT:
  		fatal("There's a special handler for this mismatch type, "
  		      "we should never get here.");
  		break;

  	}
  	fprintf(stderr, "
  ");

  }

  static void default_mismatch_handler(const char *modname, struct elf_info *elf,
  				     const struct sectioncheck* const mismatch,
  				     Elf_Rela *r, Elf_Sym *sym, const char *fromsec)

  {
  	const char *tosec;

  	Elf_Sym *to;
  	Elf_Sym *from;
  	const char *tosym;
  	const char *fromsym;

  	from = find_elf_symbol2(elf, r->r_offset, fromsec);
  	fromsym = sym_name(elf, from);

  
  	if (!strncmp(fromsym, "reference___initcall",
  		     sizeof("reference___initcall")-1))
  		return;

  	tosec = sec_name(elf, get_secindex(elf, sym));
  	to = find_elf_symbol(elf, r->r_addend, sym);
  	tosym = sym_name(elf, to);

  	/* check whitelist - we may ignore it */
  	if (secref_whitelist(mismatch,
  			     fromsec, fromsym, tosec, tosym)) {
  		report_sec_mismatch(modname, mismatch,
  				    fromsec, r->r_offset, fromsym,
  				    is_function(from), tosec, tosym,
  				    is_function(to));
  	}
  }

  static int is_executable_section(struct elf_info* elf, unsigned int section_index)
  {
  	if (section_index > elf->num_sections)
  		fatal("section_index is outside elf->num_sections!
  ");
  
  	return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
  }
  
  /*
   * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
   * to know the sizeof(struct exception_table_entry) for the target architecture.
   */
  static unsigned int extable_entry_size = 0;

  static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)

  {
  	/*
  	 * If we're currently checking the second relocation within __ex_table,
  	 * that relocation offset tells us the offsetof(struct
  	 * exception_table_entry, fixup) which is equal to sizeof(struct
  	 * exception_table_entry) divided by two.  We use that to our advantage
  	 * since there's no portable way to get that size as every architecture
  	 * seems to go with different sized types.  Not pretty but better than
  	 * hard-coding the size for every architecture..
  	 */

  	if (!extable_entry_size)

  		extable_entry_size = r->r_offset * 2;
  }

  static inline bool is_extable_fault_address(Elf_Rela *r)
  {

  	/*
  	 * extable_entry_size is only discovered after we've handled the
  	 * _second_ relocation in __ex_table, so only abort when we're not
  	 * handling the first reloc and extable_entry_size is zero.
  	 */
  	if (r->r_offset && extable_entry_size == 0)

  		fatal("extable_entry size hasn't been discovered!
  ");
  
  	return ((r->r_offset == 0) ||
  		(r->r_offset % extable_entry_size == 0));
  }

  #define is_second_extable_reloc(Start, Cur, Sec)			\
  	(((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))

  static void report_extable_warnings(const char* modname, struct elf_info* elf,
  				    const struct sectioncheck* const mismatch,
  				    Elf_Rela* r, Elf_Sym* sym,
  				    const char* fromsec, const char* tosec)
  {
  	Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
  	const char* fromsym_name = sym_name(elf, fromsym);
  	Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
  	const char* tosym_name = sym_name(elf, tosym);
  	const char* from_pretty_name;
  	const char* from_pretty_name_p;
  	const char* to_pretty_name;
  	const char* to_pretty_name_p;
  
  	get_pretty_name(is_function(fromsym),
  			&from_pretty_name, &from_pretty_name_p);
  	get_pretty_name(is_function(tosym),
  			&to_pretty_name, &to_pretty_name_p);
  
  	warn("%s(%s+0x%lx): Section mismatch in reference"
  	     " from the %s %s%s to the %s %s:%s%s
  ",
  	     modname, fromsec, (long)r->r_offset, from_pretty_name,
  	     fromsym_name, from_pretty_name_p,
  	     to_pretty_name, tosec, tosym_name, to_pretty_name_p);
  
  	if (!match(tosec, mismatch->bad_tosec) &&
  	    is_executable_section(elf, get_secindex(elf, sym)))
  		fprintf(stderr,
  			"The relocation at %s+0x%lx references
  "
  			"section \"%s\" which is not in the list of
  "
  			"authorized sections.  If you're adding a new section
  "
  			"and/or if this reference is valid, add \"%s\" to the
  "
  			"list of authorized sections to jump to on fault.
  "
  			"This can be achieved by adding \"%s\" to 
  "
  			"OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.
  ",
  			fromsec, (long)r->r_offset, tosec, tosec, tosec);
  }
  
  static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
  				     const struct sectioncheck* const mismatch,
  				     Elf_Rela* r, Elf_Sym* sym,
  				     const char *fromsec)
  {
  	const char* tosec = sec_name(elf, get_secindex(elf, sym));
  
  	sec_mismatch_count++;
  
  	if (sec_mismatch_verbose)
  		report_extable_warnings(modname, elf, mismatch, r, sym,
  					fromsec, tosec);
  
  	if (match(tosec, mismatch->bad_tosec))
  		fatal("The relocation at %s+0x%lx references
  "
  		      "section \"%s\" which is black-listed.
  "
  		      "Something is seriously wrong and should be fixed.
  "
  		      "You might get more information about where this is
  "
  		      "coming from by using scripts/check_extable.sh %s
  ",
  		      fromsec, (long)r->r_offset, tosec, modname);
  	else if (!is_executable_section(elf, get_secindex(elf, sym))) {
  		if (is_extable_fault_address(r))
  			fatal("The relocation at %s+0x%lx references
  "
  			      "section \"%s\" which is not executable, IOW
  "
  			      "it is not possible for the kernel to fault
  "
  			      "at that address.  Something is seriously wrong
  "
  			      "and should be fixed.
  ",
  			      fromsec, (long)r->r_offset, tosec);
  		else
  			fatal("The relocation at %s+0x%lx references
  "
  			      "section \"%s\" which is not executable, IOW
  "
  			      "the kernel will fault if it ever tries to
  "
  			      "jump to it.  Something is seriously wrong
  "
  			      "and should be fixed.
  ",
  			      fromsec, (long)r->r_offset, tosec);
  	}
  }

  static void check_section_mismatch(const char *modname, struct elf_info *elf,
  				   Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
  {
  	const char *tosec = sec_name(elf, get_secindex(elf, sym));;
  	const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);

  	if (mismatch) {

  		if (mismatch->handler)
  			mismatch->handler(modname, elf,  mismatch,
  					  r, sym, fromsec);
  		else
  			default_mismatch_handler(modname, elf, mismatch,
  						 r, sym, fromsec);

  	}
  }

  static unsigned int *reloc_location(struct elf_info *elf,

  				    Elf_Shdr *sechdr, Elf_Rela *r)

  {
  	Elf_Shdr *sechdrs = elf->sechdrs;

  	int section = sechdr->sh_info;

  
  	return (void *)elf->hdr + sechdrs[section].sh_offset +

  		r->r_offset;

  }

  static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)

  {
  	unsigned int r_typ = ELF_R_TYPE(r->r_info);

  	unsigned int *location = reloc_location(elf, sechdr, r);

  
  	switch (r_typ) {
  	case R_386_32:
  		r->r_addend = TO_NATIVE(*location);
  		break;
  	case R_386_PC32:
  		r->r_addend = TO_NATIVE(*location) + 4;
  		/* For CONFIG_RELOCATABLE=y */
  		if (elf->hdr->e_type == ET_EXEC)
  			r->r_addend += r->r_offset;
  		break;
  	}
  	return 0;
  }

  #ifndef R_ARM_CALL
  #define R_ARM_CALL	28
  #endif
  #ifndef R_ARM_JUMP24
  #define R_ARM_JUMP24	29
  #endif

  #ifndef	R_ARM_THM_CALL
  #define	R_ARM_THM_CALL		10
  #endif
  #ifndef	R_ARM_THM_JUMP24
  #define	R_ARM_THM_JUMP24	30
  #endif
  #ifndef	R_ARM_THM_JUMP19
  #define	R_ARM_THM_JUMP19	51
  #endif

  static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)

  {
  	unsigned int r_typ = ELF_R_TYPE(r->r_info);
  
  	switch (r_typ) {
  	case R_ARM_ABS32:
  		/* From ARM ABI: (S + A) | T */

  		r->r_addend = (int)(long)

  			      (elf->symtab_start + ELF_R_SYM(r->r_info));

  		break;
  	case R_ARM_PC24:

  	case R_ARM_CALL:
  	case R_ARM_JUMP24:

  	case R_ARM_THM_CALL:
  	case R_ARM_THM_JUMP24:
  	case R_ARM_THM_JUMP19:

  		/* From ARM ABI: ((S + A) | T) - P */

  		r->r_addend = (int)(long)(elf->hdr +

  			      sechdr->sh_offset +
  			      (r->r_offset - sechdr->sh_addr));

  		break;
  	default:
  		return 1;
  	}
  	return 0;
  }

  static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)

  {
  	unsigned int r_typ = ELF_R_TYPE(r->r_info);

  	unsigned int *location = reloc_location(elf, sechdr, r);

  	unsigned int inst;
  
  	if (r_typ == R_MIPS_HI16)
  		return 1;	/* skip this */
  	inst = TO_NATIVE(*location);
  	switch (r_typ) {
  	case R_MIPS_LO16:
  		r->r_addend = inst & 0xffff;
  		break;
  	case R_MIPS_26:
  		r->r_addend = (inst & 0x03ffffff) << 2;
  		break;
  	case R_MIPS_32:
  		r->r_addend = inst;
  		break;
  	}
  	return 0;
  }

  static void section_rela(const char *modname, struct elf_info *elf,

  			 Elf_Shdr *sechdr)

  {
  	Elf_Sym  *sym;
  	Elf_Rela *rela;
  	Elf_Rela r;
  	unsigned int r_sym;
  	const char *fromsec;

  	Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;

  	Elf_Rela *stop  = (void *)start + sechdr->sh_size;

  	fromsec = sech_name(elf, sechdr);

  	fromsec += strlen(".rela");
  	/* if from section (name) is know good then skip it */

  	if (match(fromsec, section_white_list))

  		return;

  	for (rela = start; rela < stop; rela++) {
  		r.r_offset = TO_NATIVE(rela->r_offset);
  #if KERNEL_ELFCLASS == ELFCLASS64

  		if (elf->hdr->e_machine == EM_MIPS) {

  			unsigned int r_typ;
  			r_sym = ELF64_MIPS_R_SYM(rela->r_info);
  			r_sym = TO_NATIVE(r_sym);
  			r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
  			r.r_info = ELF64_R_INFO(r_sym, r_typ);
  		} else {
  			r.r_info = TO_NATIVE(rela->r_info);
  			r_sym = ELF_R_SYM(r.r_info);
  		}
  #else
  		r.r_info = TO_NATIVE(rela->r_info);
  		r_sym = ELF_R_SYM(r.r_info);
  #endif
  		r.r_addend = TO_NATIVE(rela->r_addend);
  		sym = elf->symtab_start + r_sym;
  		/* Skip special sections */

  		if (is_shndx_special(sym->st_shndx))

  			continue;

  		if (is_second_extable_reloc(start, rela, fromsec))
  			find_extable_entry_size(fromsec, &r);

  		check_section_mismatch(modname, elf, &r, sym, fromsec);