Skip to content
Snippets Groups Projects
Select Git revision
  • 1e71bac5bf5750e7d65ee0a11f2dd6324cedb5c0
  • master default protected
  • 3.0
  • develop
  • revert-2069-tripleVersion
  • 3.1
  • rest-protocol
  • feat/remoting_rocketmq
  • dapr-support
  • 1.5
  • 1.4
  • 1.3
  • 1.2
  • 1.1
  • v3.0.3-rc2
  • v3.0.3-rc1
  • v3.0.2
  • v1.5.8
  • v1.5.9-rc1
  • v3.0.1
  • v1.5.8-rc1
  • v3.0.0
  • v3.0.0-rc4-1
  • v3.0.0-rc4
  • v3.0.0-rc3
  • v1.5.7
  • v1.5.7-rc2
  • v3.0.0-rc2
  • remove
  • v1.5.7-rc1
  • v3.0.0-rc1
  • v1.5.7-rc1-tmp
  • 1.5.6
  • v1.5.6
34 results

client.go

Blame
  • modpost.c 66.86 KiB
    /* 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/linux/license.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
    };
    
    /* In kernel, this size is defined in linux/module.h;
     * here we use Elf_Addr instead of long for covering cross-compile
     */
    
    #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
    
    #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.\n", expr);
    
    	return ptr;
    }
    
    char *read_text_file(const char *filename)
    {
    	struct stat st;
    	size_t nbytes;
    	int fd;
    	char *buf;
    
    	fd = open(filename, O_RDONLY);
    	if (fd < 0) {
    		perror(filename);
    		exit(1);
    	}
    
    	if (fstat(fd, &st) < 0) {
    		perror(filename);
    		exit(1);
    	}
    
    	buf = NOFAIL(malloc(st.st_size + 1));
    
    	nbytes = st.st_size;
    
    	while (nbytes) {
    		ssize_t bytes_read;
    
    		bytes_read = read(fd, buf, nbytes);
    		if (bytes_read < 0) {
    			perror(filename);
    			exit(1);
    		}
    
    		nbytes -= bytes_read;
    	}
    	buf[st.st_size] = '\0';
    
    	close(fd);
    
    	return buf;
    }
    
    char *get_line(char **stringp)
    {
    	char *orig = *stringp, *next;
    
    	/* do not return the unwanted extra line at EOF */
    	if (!orig || *orig == '\0')
    		return NULL;
    
    	next = strchr(orig, '\n');
    	if (next)
    		*next++ = '\0';
    
    	*stringp = next;
    
    	return orig;
    }
    
    /* A list of all modules we processed */
    static struct module *modules;
    
    static struct module *find_module(const 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 *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
    {
    	return (void *)elf->hdr +
    		elf->sechdrs[elf->secindex_strings].sh_offset +
    		sechdr->sh_name;
    }
    
    static const char *sec_name(struct elf_info *elf, int secindex)
    {
    	return sech_name(elf, &elf->sechdrs[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\n", 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 != '\n' && (*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)\n", 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\n", (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\n", 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\n", 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?\n", 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\n",
    			      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, "__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 (strstarts(symname, "_restgpr_") ||
    		    strstarts(symname, "_savegpr_") ||
    		    strstarts(symname, "_rest32gpr_") ||
    		    strstarts(symname, "_save32gpr_") ||
    		    strstarts(symname, "_restvr_") ||
    		    strstarts(symname, "_savevr_"))
    			return 1;
    	if (info->hdr->e_machine == EM_PPC64)
    		/* Special register function linked on all modules during final link of .ko */
    		if (strstarts(symname, "_restgpr0_") ||
    		    strstarts(symname, "_savegpr0_") ||
    		    strstarts(symname, "_restvr_") ||
    		    strstarts(symname, "_savevr_") ||
    		    strcmp(symname, ".TOC.") == 0)
    			return 1;
    	/* Do not ignore this symbol */
    	return 0;
    }
    
    static void handle_modversions(struct module *mod, struct elf_info *info,
    			       Elf_Sym *sym, const char *symname)
    {
    	unsigned int crc;
    	enum export export;
    	bool is_crc = false;
    
    	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
    	    strstarts(symname, "__ksymtab"))
    		export = export_from_secname(info, get_secindex(info, sym));
    	else
    		export = export_from_sec(info, get_secindex(info, sym));
    
    	/* CRC'd symbol */
    	if (strstarts(symname, "__crc_")) {
    		is_crc = true;
    		crc = (unsigned int) sym->st_value;
    		if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
    			unsigned int *crcp;
    
    			/* symbol points to the CRC in the ELF object */
    			crcp = (void *)info->hdr + sym->st_value +
    			       info->sechdrs[sym->st_shndx].sh_offset -
    			       (info->hdr->e_type != ET_REL ?
    				info->sechdrs[sym->st_shndx].sh_addr : 0);
    			crc = TO_NATIVE(*crcp);
    		}
    		sym_update_crc(symname + strlen("__crc_"), mod, crc,
    				export);
    	}
    
    	switch (sym->st_shndx) {
    	case SHN_COMMON:
    		if (strstarts(symname, "__gnu_lto_")) {
    			/* Should warn here, but modpost runs before the linker */
    		} else
    			warn("\"%s\" [%s] is COMMON symbol\n", 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 = NOFAIL(strdup(symname));
    				munged[0] = '_';
    				munged[1] = toupper(munged[1]);
    				symname = munged;
    			}
    		}
    #endif
    
    		if (is_crc) {
    			const char *e = is_vmlinux(mod->name) ?"":".ko";
    			warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
    			     symname + strlen("__crc_"), mod->name, e);
    		}
    		mod->unres = alloc_symbol(symname,
    					  ELF_ST_BIND(sym->st_info) == STB_WEAK,
    					  mod->unres);
    		break;
    	default:
    		/* All exported symbols */
    		if (strstarts(symname, "__ksymtab_")) {
    			sym_add_exported(symname + strlen("__ksymtab_"), mod,
    					export);
    		}
    		if (strcmp(symname, "init_module") == 0)
    			mod->has_init = 1;
    		if (strcmp(symname, "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(struct elf_info *info, const char *tag,
    			      char *prev)
    {
    	char *p;
    	unsigned int taglen = strlen(tag);
    	char *modinfo = info->modinfo;
    	unsigned long size = info->modinfo_len;
    
    	if (prev) {
    		size -= prev - modinfo;
    		modinfo = next_string(prev, &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(struct elf_info *info, const char *tag)
    
    {
    	return get_next_modinfo(info, 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)";
    }
    
    /* 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",	/* record-gcc-switches */
    	".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*",
    	".discard.*",
    	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.\n"
    		     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
    		     "Note that for example <linux/init.h> contains\n"
    		     "section definitions for use in .S files.\n\n",
    		     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", ".cpuidle.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
    	 * 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.*
     *
     * Pattern 6:
     *   Hide section mismatch warnings for ELF local symbols.  The goal
     *   is to eliminate false positive modpost warnings caused by
     *   compiler-generated ELF local symbol names such as ".LANCHOR1".
     *   Autogenerated symbol names bypass modpost's "Pattern 2"
     *   whitelisting, which relies on pattern-matching against symbol
     *   names to work.  (One situation where gcc can autogenerate ELF
     *   local symbols is when "-fsection-anchors" is used.)
     **/
    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) &&
    	    strstarts(fromsym, "__param"))
    		return 0;
    
    	/* Check for pattern 1a */
    	if (strcmp(tosec, ".init.text") == 0 &&
    	    match(fromsec, data_sections) &&
    	    strstarts(fromsym, "__param_ops_"))
    		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;
    
    	/* Check for pattern 6 */
    	if (strstarts(fromsym, ".L"))
    		return 0;
    
    	return 1;
    }
    
    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 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 (!is_valid_name(elf, sym))
    			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;
    }
    
    /*
     * 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 = NOFAIL(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 NOFAIL(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, "\n");
    }
    
    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\n",
    	     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\n"
    		"the %s %s%s%s.\n"
    		"This is often because %s lacks a %s\n"
    		"annotation or the annotation of %s is wrong.\n",
    		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\n"
    		"the %s %s%s%s\n"
    		"If the reference is valid then annotate the\n"
    		"variable with __init* or __refdata (see linux/init.h) "
    		"or name the variable:\n",
    		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.\n"
    		"Often the %s %s%s has valid usage outside the exit section\n"
    		"and the fix is to remove the %sannotation of %s.\n",
    		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\n"
    		"the %s %s%s%s\n"
    		"If the reference is valid then annotate the\n"
    		"variable with __exit* (see linux/init.h) or "
    		"name the variable:\n",
    		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\n"
    		"a %s %s%s%s.\n"
    		"If %s is only used by %s then\n"
    		"annotate %s with a matching annotation.\n",
    		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\n"
    		"a %s %s%s%s.\n"
    		"This is often seen when error handling "
    		"in the init function\n"
    		"uses functionality in the exit path.\n"
    		"The fix is often to remove the %sannotation of\n"
    		"%s%s so it may be used outside an exit section.\n",
    		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\n"
    		"a %s %s%s%s.\n"
    		"This is often seen when error handling "
    		"in the exit function\n"
    		"uses functionality in the init path.\n"
    		"The fix is often to remove the %sannotation of\n"
    		"%s%s so it may be used outside an init section.\n",
    		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\n"
    		"Fix this by removing the %sannotation of %s "
    		"or drop the export.\n",
    		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, "\n");
    }
    
    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 (strstarts(fromsym, "reference___initcall"))
    		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!\n");
    
    	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!\n");
    
    	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\n",
    	     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\n"
    			"section \"%s\" which is not in the list of\n"
    			"authorized sections.  If you're adding a new section\n"
    			"and/or if this reference is valid, add \"%s\" to the\n"
    			"list of authorized sections to jump to on fault.\n"
    			"This can be achieved by adding \"%s\" to \n"
    			"OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
    			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\n"
    		      "section \"%s\" which is black-listed.\n"
    		      "Something is seriously wrong and should be fixed.\n"
    		      "You might get more information about where this is\n"
    		      "coming from by using scripts/check_extable.sh %s\n",
    		      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\n"
    			      "section \"%s\" which is not executable, IOW\n"
    			      "it is not possible for the kernel to fault\n"
    			      "at that address.  Something is seriously wrong\n"
    			      "and should be fixed.\n",
    			      fromsec, (long)r->r_offset, tosec);
    		else
    			fatal("The relocation at %s+0x%lx references\n"
    			      "section \"%s\" which is not executable, IOW\n"
    			      "the kernel will fault if it ever tries to\n"
    			      "jump to it.  Something is seriously wrong\n"
    			      "and should be fixed.\n",
    			      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);
    	}
    }
    
    static void section_rel(const char *modname, struct elf_info *elf,
    			Elf_Shdr *sechdr)
    {
    	Elf_Sym *sym;
    	Elf_Rel *rel;
    	Elf_Rela r;
    	unsigned int r_sym;
    	const char *fromsec;
    
    	Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
    	Elf_Rel *stop  = (void *)start + sechdr->sh_size;
    
    	fromsec = sech_name(elf, sechdr);
    	fromsec += strlen(".rel");
    	/* if from section (name) is know good then skip it */
    	if (match(fromsec, section_white_list))
    		return;
    
    	for (rel = start; rel < stop; rel++) {
    		r.r_offset = TO_NATIVE(rel->r_offset);
    #if KERNEL_ELFCLASS == ELFCLASS64
    		if (elf->hdr->e_machine == EM_MIPS) {
    			unsigned int r_typ;
    			r_sym = ELF64_MIPS_R_SYM(rel->r_info);
    			r_sym = TO_NATIVE(r_sym);
    			r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
    			r.r_info = ELF64_R_INFO(r_sym, r_typ);
    		} else {
    			r.r_info = TO_NATIVE(rel->r_info);
    			r_sym = ELF_R_SYM(r.r_info);
    		}
    #else
    		r.r_info = TO_NATIVE(rel->r_info);
    		r_sym = ELF_R_SYM(r.r_info);
    #endif
    		r.r_addend = 0;
    		switch (elf->hdr->e_machine) {
    		case EM_386:
    			if (addend_386_rel(elf, sechdr, &r))
    				continue;
    			break;
    		case EM_ARM:
    			if (addend_arm_rel(elf, sechdr, &r))
    				continue;
    			break;
    		case EM_MIPS:
    			if (addend_mips_rel(elf, sechdr, &r))
    				continue;
    			break;
    		}
    		sym = elf->symtab_start + r_sym;
    		/* Skip special sections */
    		if (is_shndx_special(sym->st_shndx))
    			continue;
    		if (is_second_extable_reloc(start, rel, fromsec))
    			find_extable_entry_size(fromsec, &r);
    		check_section_mismatch(modname, elf, &r, sym, fromsec);
    	}
    }
    
    /**
     * A module includes a number of sections that are discarded
     * either when loaded or when used as built-in.
     * For loaded modules all functions marked __init and all data
     * marked __initdata will be discarded when the module has been initialized.
     * Likewise for modules used built-in the sections marked __exit
     * are discarded because __exit marked function are supposed to be called
     * only when a module is unloaded which never happens for built-in modules.
     * The check_sec_ref() function traverses all relocation records
     * to find all references to a section that reference a section that will
     * be discarded and warns about it.
     **/
    static void check_sec_ref(struct module *mod, const char *modname,
    			  struct elf_info *elf)
    {
    	int i;
    	Elf_Shdr *sechdrs = elf->sechdrs;
    
    	/* Walk through all sections */
    	for (i = 0; i < elf->num_sections; i++) {
    		check_section(modname, elf, &elf->sechdrs[i]);
    		/* We want to process only relocation sections and not .init */
    		if (sechdrs[i].sh_type == SHT_RELA)
    			section_rela(modname, elf, &elf->sechdrs[i]);
    		else if (sechdrs[i].sh_type == SHT_REL)
    			section_rel(modname, elf, &elf->sechdrs[i]);
    	}
    }
    
    static char *remove_dot(char *s)
    {
    	size_t n = strcspn(s, ".");
    
    	if (n && s[n]) {
    		size_t m = strspn(s + n + 1, "0123456789");
    		if (m && (s[n + m] == '.' || s[n + m] == 0))
    			s[n] = 0;
    	}
    	return s;
    }
    
    static void read_symbols(const char *modname)
    {
    	const char *symname;
    	char *version;
    	char *license;
    	struct module *mod;
    	struct elf_info info = { };
    	Elf_Sym *sym;
    
    	if (!parse_elf(&info, modname))
    		return;
    
    	mod = new_module(modname);
    
    	/* When there's no vmlinux, don't print warnings about
    	 * unresolved symbols (since there'll be too many ;) */
    	if (is_vmlinux(modname)) {
    		have_vmlinux = 1;
    		mod->skip = 1;
    	}
    
    	license = get_modinfo(&info, "license");
    	if (!license && !is_vmlinux(modname))
    		warn("modpost: missing MODULE_LICENSE() in %s\n"
    		     "see include/linux/module.h for "
    		     "more information\n", modname);
    	while (license) {
    		if (license_is_gpl_compatible(license))
    			mod->gpl_compatible = 1;
    		else {
    			mod->gpl_compatible = 0;
    			break;
    		}
    		license = get_next_modinfo(&info, "license", license);
    	}
    
    	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
    		symname = remove_dot(info.strtab + sym->st_name);
    
    		handle_modversions(mod, &info, sym, symname);
    		handle_moddevtable(mod, &info, sym, symname);
    	}
    	if (!is_vmlinux(modname) || vmlinux_section_warnings)
    		check_sec_ref(mod, modname, &info);
    
    	version = get_modinfo(&info, "version");
    	if (version)
    		maybe_frob_rcs_version(modname, version, info.modinfo,
    				       version - (char *)info.hdr);
    	if (version || (all_versions && !is_vmlinux(modname)))
    		get_src_version(modname, mod->srcversion,
    				sizeof(mod->srcversion)-1);
    
    	parse_elf_finish(&info);
    
    	/* Our trick to get versioning for module struct etc. - it's
    	 * never passed as an argument to an exported function, so
    	 * the automatic versioning doesn't pick it up, but it's really
    	 * important anyhow */
    	if (modversions)
    		mod->unres = alloc_symbol("module_layout", 0, mod->unres);
    }
    
    static void read_symbols_from_files(const char *filename)
    {
    	FILE *in = stdin;
    	char fname[PATH_MAX];
    
    	if (strcmp(filename, "-") != 0) {
    		in = fopen(filename, "r");
    		if (!in)
    			fatal("Can't open filenames file %s: %m", filename);
    	}
    
    	while (fgets(fname, PATH_MAX, in) != NULL) {
    		if (strends(fname, "\n"))
    			fname[strlen(fname)-1] = '\0';
    		read_symbols(fname);
    	}
    
    	if (in != stdin)
    		fclose(in);
    }
    
    #define SZ 500
    
    /* We first write the generated file into memory using the
     * following helper, then compare to the file on disk and
     * only update the later if anything changed */
    
    void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
    						      const char *fmt, ...)
    {
    	char tmp[SZ];
    	int len;
    	va_list ap;
    
    	va_start(ap, fmt);
    	len = vsnprintf(tmp, SZ, fmt, ap);
    	buf_write(buf, tmp, len);
    	va_end(ap);
    }
    
    void buf_write(struct buffer *buf, const char *s, int len)
    {
    	if (buf->size - buf->pos < len) {
    		buf->size += len + SZ;
    		buf->p = NOFAIL(realloc(buf->p, buf->size));
    	}
    	strncpy(buf->p + buf->pos, s, len);
    	buf->pos += len;
    }
    
    static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
    {
    	const char *e = is_vmlinux(m) ?"":".ko";
    
    	switch (exp) {
    	case export_gpl:
    		fatal("modpost: GPL-incompatible module %s%s "
    		      "uses GPL-only symbol '%s'\n", m, e, s);
    		break;
    	case export_unused_gpl:
    		fatal("modpost: GPL-incompatible module %s%s "
    		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
    		break;
    	case export_gpl_future:
    		warn("modpost: GPL-incompatible module %s%s "
    		      "uses future GPL-only symbol '%s'\n", m, e, s);
    		break;
    	case export_plain:
    	case export_unused:
    	case export_unknown:
    		/* ignore */
    		break;
    	}
    }
    
    static void check_for_unused(enum export exp, const char *m, const char *s)
    {
    	const char *e = is_vmlinux(m) ?"":".ko";
    
    	switch (exp) {
    	case export_unused:
    	case export_unused_gpl:
    		warn("modpost: module %s%s "
    		      "uses symbol '%s' marked UNUSED\n", m, e, s);
    		break;
    	default:
    		/* ignore */
    		break;
    	}
    }
    
    static void check_exports(struct module *mod)
    {
    	struct symbol *s, *exp;
    
    	for (s = mod->unres; s; s = s->next) {
    		const char *basename;
    		exp = find_symbol(s->name);
    		if (!exp || exp->module == mod)
    			continue;
    		basename = strrchr(mod->name, '/');
    		if (basename)
    			basename++;
    		else
    			basename = mod->name;
    		if (!mod->gpl_compatible)
    			check_for_gpl_usage(exp->export, basename, exp->name);
    		check_for_unused(exp->export, basename, exp->name);
    	}
    }
    
    static int check_modname_len(struct module *mod)
    {
    	const char *mod_name;
    
    	mod_name = strrchr(mod->name, '/');
    	if (mod_name == NULL)
    		mod_name = mod->name;
    	else
    		mod_name++;
    	if (strlen(mod_name) >= MODULE_NAME_LEN) {
    		merror("module name is too long [%s.ko]\n", mod->name);
    		return 1;
    	}
    
    	return 0;
    }
    
    /**
     * Header for the generated file
     **/
    static void add_header(struct buffer *b, struct module *mod)
    {
    	buf_printf(b, "#include <linux/build-salt.h>\n");
    	buf_printf(b, "#include <linux/module.h>\n");
    	buf_printf(b, "#include <linux/vermagic.h>\n");
    	buf_printf(b, "#include <linux/compiler.h>\n");
    	buf_printf(b, "\n");
    	buf_printf(b, "BUILD_SALT;\n");
    	buf_printf(b, "\n");
    	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
    	buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
    	buf_printf(b, "\n");
    	buf_printf(b, "__visible struct module __this_module\n");
    	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
    	buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
    	if (mod->has_init)
    		buf_printf(b, "\t.init = init_module,\n");
    	if (mod->has_cleanup)
    		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
    			      "\t.exit = cleanup_module,\n"
    			      "#endif\n");
    	buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
    	buf_printf(b, "};\n");
    }
    
    static void add_intree_flag(struct buffer *b, int is_intree)
    {
    	if (is_intree)
    		buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
    }
    
    /* Cannot check for assembler */
    static void add_retpoline(struct buffer *b)
    {
    	buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
    	buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
    	buf_printf(b, "#endif\n");
    }
    
    static void add_staging_flag(struct buffer *b, const char *name)
    {
    	if (strstarts(name, "drivers/staging"))
    		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
    }
    
    /**
     * Record CRCs for unresolved symbols
     **/
    static int add_versions(struct buffer *b, struct module *mod)
    {
    	struct symbol *s, *exp;
    	int err = 0;
    
    	for (s = mod->unres; s; s = s->next) {
    		exp = find_symbol(s->name);
    		if (!exp || exp->module == mod) {
    			if (have_vmlinux && !s->weak) {
    				if (warn_unresolved) {
    					warn("\"%s\" [%s.ko] undefined!\n",
    					     s->name, mod->name);
    				} else {
    					merror("\"%s\" [%s.ko] undefined!\n",
    					       s->name, mod->name);
    					err = 1;
    				}
    			}
    			continue;
    		}
    		s->module = exp->module;
    		s->crc_valid = exp->crc_valid;
    		s->crc = exp->crc;
    	}
    
    	if (!modversions)
    		return err;
    
    	buf_printf(b, "\n");
    	buf_printf(b, "static const struct modversion_info ____versions[]\n");
    	buf_printf(b, "__used\n");
    	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
    
    	for (s = mod->unres; s; s = s->next) {
    		if (!s->module)
    			continue;
    		if (!s->crc_valid) {
    			warn("\"%s\" [%s.ko] has no CRC!\n",
    				s->name, mod->name);
    			continue;
    		}
    		if (strlen(s->name) >= MODULE_NAME_LEN) {
    			merror("too long symbol \"%s\" [%s.ko]\n",
    			       s->name, mod->name);
    			err = 1;
    			break;
    		}
    		buf_printf(b, "\t{ %#8x, \"%s\" },\n",
    			   s->crc, s->name);
    	}
    
    	buf_printf(b, "};\n");
    
    	return err;
    }
    
    static void add_depends(struct buffer *b, struct module *mod,
    			struct module *modules)
    {
    	struct symbol *s;
    	struct module *m;
    	int first = 1;
    
    	for (m = modules; m; m = m->next)
    		m->seen = is_vmlinux(m->name);
    
    	buf_printf(b, "\n");
    	buf_printf(b, "static const char __module_depends[]\n");
    	buf_printf(b, "__used\n");
    	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
    	buf_printf(b, "\"depends=");
    	for (s = mod->unres; s; s = s->next) {
    		const char *p;
    		if (!s->module)
    			continue;
    
    		if (s->module->seen)
    			continue;
    
    		s->module->seen = 1;
    		p = strrchr(s->module->name, '/');
    		if (p)
    			p++;
    		else
    			p = s->module->name;
    		buf_printf(b, "%s%s", first ? "" : ",", p);
    		first = 0;
    	}
    	buf_printf(b, "\";\n");
    }
    
    static void add_srcversion(struct buffer *b, struct module *mod)
    {
    	if (mod->srcversion[0]) {
    		buf_printf(b, "\n");
    		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
    			   mod->srcversion);
    	}
    }
    
    static void write_if_changed(struct buffer *b, const char *fname)
    {
    	char *tmp;
    	FILE *file;
    	struct stat st;
    
    	file = fopen(fname, "r");
    	if (!file)
    		goto write;
    
    	if (fstat(fileno(file), &st) < 0)
    		goto close_write;
    
    	if (st.st_size != b->pos)
    		goto close_write;
    
    	tmp = NOFAIL(malloc(b->pos));
    	if (fread(tmp, 1, b->pos, file) != b->pos)
    		goto free_write;
    
    	if (memcmp(tmp, b->p, b->pos) != 0)
    		goto free_write;
    
    	free(tmp);
    	fclose(file);
    	return;
    
     free_write:
    	free(tmp);
     close_write:
    	fclose(file);
     write:
    	file = fopen(fname, "w");
    	if (!file) {
    		perror(fname);
    		exit(1);
    	}
    	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
    		perror(fname);
    		exit(1);
    	}
    	fclose(file);
    }
    
    /* parse Module.symvers file. line format:
     * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
     **/
    static void read_dump(const char *fname, unsigned int kernel)
    {
    	unsigned long size, pos = 0;
    	void *file = grab_file(fname, &size);
    	char *line;
    
    	if (!file)
    		/* No symbol versions, silently ignore */
    		return;
    
    	while ((line = get_next_line(&pos, file, size))) {
    		char *symname, *modname, *d, *export, *end;
    		unsigned int crc;
    		struct module *mod;
    		struct symbol *s;
    
    		if (!(symname = strchr(line, '\t')))
    			goto fail;
    		*symname++ = '\0';
    		if (!(modname = strchr(symname, '\t')))
    			goto fail;
    		*modname++ = '\0';
    		if ((export = strchr(modname, '\t')) != NULL)
    			*export++ = '\0';
    		if (export && ((end = strchr(export, '\t')) != NULL))
    			*end = '\0';
    		crc = strtoul(line, &d, 16);
    		if (*symname == '\0' || *modname == '\0' || *d != '\0')
    			goto fail;
    		mod = find_module(modname);
    		if (!mod) {
    			if (is_vmlinux(modname))
    				have_vmlinux = 1;
    			mod = new_module(modname);
    			mod->skip = 1;
    		}
    		s = sym_add_exported(symname, mod, export_no(export));
    		s->kernel    = kernel;
    		s->preloaded = 1;
    		sym_update_crc(symname, mod, crc, export_no(export));
    	}
    	release_file(file, size);
    	return;
    fail:
    	release_file(file, size);
    	fatal("parse error in symbol dump file\n");
    }
    
    /* For normal builds always dump all symbols.
     * For external modules only dump symbols
     * that are not read from kernel Module.symvers.
     **/
    static int dump_sym(struct symbol *sym)
    {
    	if (!external_module)
    		return 1;
    	if (sym->vmlinux || sym->kernel)
    		return 0;
    	return 1;
    }
    
    static void write_dump(const char *fname)
    {
    	struct buffer buf = { };
    	struct symbol *symbol;
    	int n;
    
    	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
    		symbol = symbolhash[n];
    		while (symbol) {
    			if (dump_sym(symbol))
    				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
    					symbol->crc, symbol->name,
    					symbol->module->name,
    					export_str(symbol->export));
    			symbol = symbol->next;
    		}
    	}
    	write_if_changed(&buf, fname);
    	free(buf.p);
    }
    
    struct ext_sym_list {
    	struct ext_sym_list *next;
    	const char *file;
    };
    
    int main(int argc, char **argv)
    {
    	struct module *mod;
    	struct buffer buf = { };
    	char *kernel_read = NULL, *module_read = NULL;
    	char *dump_write = NULL, *files_source = NULL;
    	int opt;
    	int err;
    	struct ext_sym_list *extsym_iter;
    	struct ext_sym_list *extsym_start = NULL;
    
    	while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
    		switch (opt) {
    		case 'i':
    			kernel_read = optarg;
    			break;
    		case 'I':
    			module_read = optarg;
    			external_module = 1;
    			break;
    		case 'e':
    			external_module = 1;
    			extsym_iter =
    			   NOFAIL(malloc(sizeof(*extsym_iter)));
    			extsym_iter->next = extsym_start;
    			extsym_iter->file = optarg;
    			extsym_start = extsym_iter;
    			break;
    		case 'm':
    			modversions = 1;
    			break;
    		case 'n':
    			ignore_missing_files = 1;
    			break;
    		case 'o':
    			dump_write = optarg;
    			break;
    		case 'a':
    			all_versions = 1;
    			break;
    		case 's':
    			vmlinux_section_warnings = 0;
    			break;
    		case 'S':
    			sec_mismatch_verbose = 0;
    			break;
    		case 'T':
    			files_source = optarg;
    			break;
    		case 'w':
    			warn_unresolved = 1;
    			break;
    		case 'E':
    			sec_mismatch_fatal = 1;
    			break;
    		default:
    			exit(1);
    		}
    	}
    
    	if (kernel_read)
    		read_dump(kernel_read, 1);
    	if (module_read)
    		read_dump(module_read, 0);
    	while (extsym_start) {
    		read_dump(extsym_start->file, 0);
    		extsym_iter = extsym_start->next;
    		free(extsym_start);
    		extsym_start = extsym_iter;
    	}
    
    	while (optind < argc)
    		read_symbols(argv[optind++]);
    
    	if (files_source)
    		read_symbols_from_files(files_source);
    
    	for (mod = modules; mod; mod = mod->next) {
    		if (mod->skip)
    			continue;
    		check_exports(mod);
    	}
    
    	err = 0;
    
    	for (mod = modules; mod; mod = mod->next) {
    		char fname[PATH_MAX];
    
    		if (mod->skip)
    			continue;
    
    		buf.pos = 0;
    
    		err |= check_modname_len(mod);
    		add_header(&buf, mod);
    		add_intree_flag(&buf, !external_module);
    		add_retpoline(&buf);
    		add_staging_flag(&buf, mod->name);
    		err |= add_versions(&buf, mod);
    		add_depends(&buf, mod, modules);
    		add_moddevtable(&buf, mod);
    		add_srcversion(&buf, mod);
    
    		sprintf(fname, "%s.mod.c", mod->name);
    		write_if_changed(&buf, fname);
    	}
    	if (dump_write)
    		write_dump(dump_write);
    	if (sec_mismatch_count) {
    		if (!sec_mismatch_verbose) {
    			warn("modpost: Found %d section mismatch(es).\n"
    			     "To see full details build your kernel with:\n"
    			     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
    			     sec_mismatch_count);
    		}
    		if (sec_mismatch_fatal) {
    			fatal("modpost: Section mismatches detected.\n"
    			      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
    		}
    	}
    	free(buf.p);
    
    	return err;
    }