modpost.c

/* 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? */
int modversions = 0;
/* Warn about undefined symbols? (do so if we have vmlinux) */
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;
/* 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.\n", 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 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\n", mod->name, name,
			     s->module->name,
			     is_vmlinux(s->module->name) ?"":".ko");
		} else {
			/* In case Modules.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, 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)
			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:
		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 = 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;
}

/* if sym is empty or point to a string
 * like ".[0-9]+" then return 1.
 * This is the optional prefix added by ld to some sections
 */
static int number_prefix(const char *sym)
{
	if (*sym++ == '\0')
		return 1;
	if (*sym != '.')
		return 0;
	do {
		char c = *sym++;
		if (c < '0' || c > '9')
			return 0;
	} while (*sym);
	return 1;
}

/* 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 equal to "foo" or "foo.1"
 *   where the '1' can be any number including several digits.
 *   The $ syntax is for sections where ld append a dot number
 *   to make section name unique.
 */
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 == '*') {
			if (strrcmp(sym, p + 1) == 0)
				return 1;
		}
		/* "foo*" */
		else if (*endp == '*') {
			if (strncmp(sym, p, strlen(p) - 1) == 0)
				return 1;
		}
		/* "foo$" */
		else if (*endp == '$') {
			if (strncmp(sym, p, strlen(p) - 1) == 0) {
				if (number_prefix(sym + strlen(p) - 1))
					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 *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 */
	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$", ".text.unlikely$"

#define INIT_SECTIONS      ".init.*"
#define MEM_INIT_SECTIONS  ".meminit.*"

#define EXIT_SECTIONS      ".exit.*"
#define MEM_EXIT_SECTIONS  ".memexit.*"

/* init data sections */
static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };

/* all init sections */
static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };

/* All init and exit sections (code + data) */
static const char *init_exit_sections[] =
	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };

/* data section */
static const char *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 *head_sections[] = { ".head.text*", NULL };
static const char *linker_symbols[] =
	{ "__init_begin", "_sinittext", "_einittext", 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,
};

struct sectioncheck {
	const char *fromsec[20];
	const char *tosec[20];
	enum mismatch mismatch;
	const char *symbol_white_list[20];
};

const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
 * normal code and data
 */
{
	.fromsec = { TEXT_SECTIONS, NULL },
	.tosec   = { ALL_INIT_SECTIONS, NULL },
	.mismatch = TEXT_TO_ANY_INIT,
	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
	.fromsec = { DATA_SECTIONS, NULL },
	.tosec   = { ALL_XXXINIT_SECTIONS, NULL },
	.mismatch = DATA_TO_ANY_INIT,
	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
	.fromsec = { DATA_SECTIONS, NULL },
	.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 },
	.tosec   = { ALL_EXIT_SECTIONS, NULL },
	.mismatch = TEXT_TO_ANY_EXIT,
	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
	.fromsec = { DATA_SECTIONS, NULL },
	.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 },
	.tosec   = { INIT_SECTIONS, NULL },
	.mismatch = XXXINIT_TO_SOME_INIT,
	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},