modpost.c 42.1 KB
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/* Postprocess module symbol versions
 *
 * Copyright 2003       Kai Germaschewski
 * Copyright 2002-2004  Rusty Russell, IBM Corporation
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 * Copyright 2006       Sam Ravnborg
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 * 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 ...
 */

#include <ctype.h>
#include "modpost.h"
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#include "../../include/linux/license.h"
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/* 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;
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/* If we are modposting external module set to 1 */
static int external_module = 0;
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/* Warn about section mismatch in vmlinux if set to 1 */
static int vmlinux_section_warnings = 1;
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/* Only warn about unresolved symbols */
static int warn_unresolved = 0;
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/* How a symbol is exported */
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enum export {
	export_plain,      export_unused,     export_gpl,
	export_unused_gpl, export_gpl_future, export_unknown
};
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void fatal(const char *fmt, ...)
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{
	va_list arglist;

	fprintf(stderr, "FATAL: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);

	exit(1);
}

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void warn(const char *fmt, ...)
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{
	va_list arglist;

	fprintf(stderr, "WARNING: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);
}

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void merror(const char *fmt, ...)
{
	va_list arglist;

	fprintf(stderr, "ERROR: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);
}

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

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

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

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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;

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static struct module *find_module(char *modname)
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{
	struct module *mod;

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

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static struct module *new_module(char *modname)
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{
	struct module *mod;
	char *p, *s;
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	mod = NOFAIL(malloc(sizeof(*mod)));
	memset(mod, 0, sizeof(*mod));
	p = NOFAIL(strdup(modname));

	/* strip trailing .o */
	if ((s = strrchr(p, '.')) != NULL)
		if (strcmp(s, ".o") == 0)
			*s = '\0';

	/* add to list */
	mod->name = p;
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	mod->gpl_compatible = -1;
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	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;
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	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) **/
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	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
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	enum export  export;       /* Type of export */
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	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);
}

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/**
 * 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)
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{
	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 */
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static struct symbol *new_symbol(const char *name, struct module *module,
				 enum export export)
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{
	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;
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	new->export = export;
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	return new;
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}

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static struct symbol *find_symbol(const char *name)
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{
	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;
}

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static struct {
	const char *str;
	enum export export;
} export_list[] = {
	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
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	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
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	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
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	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
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	{ .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;
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	if (!s)
		return export_unknown;
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	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 enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
{
	if (sec == elf->export_sec)
		return export_plain;
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	else if (sec == elf->export_unused_sec)
		return export_unused;
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	else if (sec == elf->export_gpl_sec)
		return export_gpl;
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	else if (sec == elf->export_unused_gpl_sec)
		return export_unused_gpl;
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	else if (sec == elf->export_gpl_future_sec)
		return export_gpl_future;
	else
		return export_unknown;
}

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/**
 * Add an exported symbol - it may have already been added without a
 * CRC, in this case just update the CRC
 **/
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static struct symbol *sym_add_exported(const char *name, struct module *mod,
				       enum export export)
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{
	struct symbol *s = find_symbol(name);

	if (!s) {
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		s = new_symbol(name, mod, export);
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	} else {
		if (!s->preloaded) {
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			warn("%s: '%s' exported twice. Previous export "
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			     "was in %s%s\n", mod->name, name,
			     s->module->name,
			     is_vmlinux(s->module->name) ?"":".ko");
		}
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	}
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	s->preloaded = 0;
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	s->vmlinux   = is_vmlinux(mod->name);
	s->kernel    = 0;
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	s->export    = export;
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	return s;
}

static void sym_update_crc(const char *name, struct module *mod,
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			   unsigned int crc, enum export export)
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{
	struct symbol *s = find_symbol(name);

	if (!s)
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		s = new_symbol(name, mod, export);
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	s->crc = crc;
	s->crc_valid = 1;
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}

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void *grab_file(const char *filename, unsigned long *size)
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{
	struct stat st;
	void *map;
	int fd;

	fd = open(filename, O_RDONLY);
	if (fd < 0 || fstat(fd, &st) != 0)
		return NULL;

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

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

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/**
  * 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)
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{
	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;
}

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void release_file(void *file, unsigned long size)
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{
	munmap(file, size);
}

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static int parse_elf(struct elf_info *info, const char *filename)
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{
	unsigned int i;
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	Elf_Ehdr *hdr;
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	Elf_Shdr *sechdrs;
	Elf_Sym  *sym;

	hdr = grab_file(filename, &info->size);
	if (!hdr) {
		perror(filename);
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		exit(1);
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	}
	info->hdr = hdr;
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	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;
	}
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	/* Fix endianness in ELF header */
	hdr->e_shoff    = TO_NATIVE(hdr->e_shoff);
	hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
	hdr->e_shnum    = TO_NATIVE(hdr->e_shnum);
	hdr->e_machine  = TO_NATIVE(hdr->e_machine);
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	hdr->e_type     = TO_NATIVE(hdr->e_type);
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	sechdrs = (void *)hdr + hdr->e_shoff;
	info->sechdrs = sechdrs;

	/* Fix endianness in section headers */
	for (i = 0; i < hdr->e_shnum; i++) {
		sechdrs[i].sh_type   = TO_NATIVE(sechdrs[i].sh_type);
		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_name   = TO_NATIVE(sechdrs[i].sh_name);
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		sechdrs[i].sh_info   = TO_NATIVE(sechdrs[i].sh_info);
		sechdrs[i].sh_addr   = TO_NATIVE(sechdrs[i].sh_addr);
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	}
	/* Find symbol table. */
	for (i = 1; i < hdr->e_shnum; i++) {
		const char *secstrings
			= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
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		const char *secname;
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		if (sechdrs[i].sh_offset > info->size) {
			fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
			return 0;
		}
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		secname = secstrings + sechdrs[i].sh_name;
		if (strcmp(secname, ".modinfo") == 0) {
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			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
			info->modinfo_len = sechdrs[i].sh_size;
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		} else if (strcmp(secname, "__ksymtab") == 0)
			info->export_sec = i;
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		else if (strcmp(secname, "__ksymtab_unused") == 0)
			info->export_unused_sec = i;
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		else if (strcmp(secname, "__ksymtab_gpl") == 0)
			info->export_gpl_sec = i;
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		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
			info->export_unused_gpl_sec = i;
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		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
			info->export_gpl_future_sec = i;

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		if (sechdrs[i].sh_type != SHT_SYMTAB)
			continue;

		info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
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		info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset
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			                         + sechdrs[i].sh_size;
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		info->strtab       = (void *)hdr +
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			             sechdrs[sechdrs[i].sh_link].sh_offset;
	}
	if (!info->symtab_start) {
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		fatal("%s has no symtab?\n", filename);
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	}
	/* 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);
	}
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	return 1;
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}

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static void parse_elf_finish(struct elf_info *info)
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{
	release_file(info->hdr, info->size);
}

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#define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
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static void handle_modversions(struct module *mod, struct elf_info *info,
			       Elf_Sym *sym, const char *symname)
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{
	unsigned int crc;
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	enum export export = export_from_sec(info, sym->st_shndx);
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	switch (sym->st_shndx) {
	case SHN_COMMON:
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		warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
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		break;
	case SHN_ABS:
		/* CRC'd symbol */
		if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
			crc = (unsigned int) sym->st_value;
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			sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
					export);
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		}
		break;
	case SHN_UNDEF:
		/* undefined symbol */
		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
			break;
		/* ignore global offset table */
		if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
			break;
		/* ignore __this_module, it will be resolved shortly */
		if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
			break;
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/* 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
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		if (info->hdr->e_machine == EM_SPARC ||
		    info->hdr->e_machine == EM_SPARCV9) {
			/* Ignore register directives. */
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			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
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				break;
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			if (symname[0] == '.') {
				char *munged = strdup(symname);
				munged[0] = '_';
				munged[1] = toupper(munged[1]);
				symname = munged;
			}
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		}
#endif
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		if (memcmp(symname, MODULE_SYMBOL_PREFIX,
			   strlen(MODULE_SYMBOL_PREFIX)) == 0)
			mod->unres = alloc_symbol(symname +
						  strlen(MODULE_SYMBOL_PREFIX),
						  ELF_ST_BIND(sym->st_info) == STB_WEAK,
						  mod->unres);
		break;
	default:
		/* All exported symbols */
		if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
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			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
					export);
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		}
		if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
			mod->has_init = 1;
		if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
			mod->has_cleanup = 1;
		break;
	}
}

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

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static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
			      const char *tag, char *info)
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{
	char *p;
	unsigned int taglen = strlen(tag);
	unsigned long size = modinfo_len;

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

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

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

{
	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
}

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/**
 * Test if string s ends in string sub
 * return 0 if match
 **/
static int strrcmp(const char *s, const char *sub)
{
        int slen, sublen;
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	if (!s || !sub)
		return 1;
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	slen = strlen(s);
        sublen = strlen(sub);
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	if ((slen == 0) || (sublen == 0))
		return 1;

        if (sublen > slen)
                return 1;

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

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/*
 * Functions used only during module init is marked __init and is stored in
 * a .init.text section. Likewise data is marked __initdata and stored in
 * a .init.data section.
 * If this section is one of these sections return 1
 * See include/linux/init.h for the details
 */
static int init_section(const char *name)
{
	if (strcmp(name, ".init") == 0)
		return 1;
	if (strncmp(name, ".init.", strlen(".init.")) == 0)
		return 1;
	return 0;
}

/*
 * Functions used only during module exit is marked __exit and is stored in
 * a .exit.text section. Likewise data is marked __exitdata and stored in
 * a .exit.data section.
 * If this section is one of these sections return 1
 * See include/linux/init.h for the details
 **/
static int exit_section(const char *name)
{
	if (strcmp(name, ".exit.text") == 0)
		return 1;
	if (strcmp(name, ".exit.data") == 0)
		return 1;
	return 0;

}

/*
 * Data sections are named like this:
 * .data | .data.rel | .data.rel.*
 * Return 1 if the specified section is a data section
 */
static int data_section(const char *name)
{
	if ((strcmp(name, ".data") == 0) ||
	    (strcmp(name, ".data.rel") == 0) ||
	    (strncmp(name, ".data.rel.", strlen(".data.rel.")) == 0))
		return 1;
	else
		return 0;
}

637 638
/**
 * Whitelist to allow certain references to pass with no warning.
639 640 641 642 643 644
 *
 * Pattern 0:
 *   Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
 *   The pattern is identified by:
 *   fromsec = .text.init.refok | .data.init.refok
 *
645 646 647 648 649 650 651
 * 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
652
 *   fromsec = .data*
653
 *   atsym   =__param*
654
 *
655
 * Pattern 2:
656
 *   Many drivers utilise a *driver container with references to
657 658 659 660
 *   add, remove, probe functions etc.
 *   These functions may often be marked __init and we do not want to
 *   warn here.
 *   the pattern is identified by:
661 662
 *   tosec   = init or exit section
 *   fromsec = data section
663
 *   atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console, *_timer
664 665
 *
 * Pattern 3:
666 667 668
 *   Whitelist all refereces from .text.head to .init.data
 *   Whitelist all refereces from .text.head to .init.text
 *
669
 * Pattern 4:
670 671 672 673 674 675 676
 *   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
677
 *
678
 **/
679
static int secref_whitelist(const char *modname, const char *tosec,
680 681
			    const char *fromsec, const char *atsym,
			    const char *refsymname)
682 683 684
{
	const char **s;
	const char *pat2sym[] = {
685
		"driver",
686
		"_template", /* scsi uses *_template a lot */
687
		"_timer",    /* arm uses ops structures named _timer a lot */
688
		"_sht",      /* scsi also used *_sht to some extent */
689 690 691
		"_ops",
		"_probe",
		"_probe_one",
692
		"_console",
693 694
		NULL
	};
695

696 697 698 699 700 701 702
	const char *pat3refsym[] = {
		"__init_begin",
		"_sinittext",
		"_einittext",
		NULL
	};

703 704 705 706 707
	/* Check for pattern 0 */
	if ((strcmp(fromsec, ".text.init.refok") == 0) ||
	    (strcmp(fromsec, ".data.init.refok") == 0))
		return 1;

708
	/* Check for pattern 1 */
709 710 711 712
	if ((strcmp(tosec, ".init.data") == 0) &&
	    (strncmp(fromsec, ".data", strlen(".data")) == 0) &&
	    (strncmp(atsym, "__param", strlen("__param")) == 0))
		return 1;
713 714

	/* Check for pattern 2 */
715 716 717 718
	if ((init_section(tosec) || exit_section(tosec)) && data_section(fromsec))
		for (s = pat2sym; *s; s++)
			if (strrcmp(atsym, *s) == 0)
				return 1;
719

720 721 722 723 724 725
	/* Check for pattern 3 */
	if ((strcmp(fromsec, ".text.head") == 0) &&
		((strcmp(tosec, ".init.data") == 0) ||
		(strcmp(tosec, ".init.text") == 0)))
	return 1;

726
	/* Check for pattern 4 */
727 728 729 730
	for (s = pat3refsym; *s; s++)
		if (strcmp(refsymname, *s) == 0)
			return 1;

731
	return 0;
732 733
}

734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750
/**
 * 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, Elf_Addr addr,
				Elf_Sym *relsym)
{
	Elf_Sym *sym;

	if (relsym->st_name != 0)
		return relsym;
	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
		if (sym->st_shndx != relsym->st_shndx)
			continue;
751 752
		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
			continue;
753 754 755 756 757 758
		if (sym->st_value == addr)
			return sym;
	}
	return NULL;
}

759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782
static inline int is_arm_mapping_symbol(const char *str)
{
	return str[0] == '$' && strchr("atd", 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);
}

783
/*
784 785 786 787
 * 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.
788 789 790 791 792 793 794 795 796 797 798
 **/
static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
				 const char *sec,
			         Elf_Sym **before, Elf_Sym **after)
{
	Elf_Sym *sym;
	Elf_Ehdr *hdr = elf->hdr;
	Elf_Addr beforediff = ~0;
	Elf_Addr afterdiff = ~0;
	const char *secstrings = (void *)hdr +
				 elf->sechdrs[hdr->e_shstrndx].sh_offset;
799

800 801 802 803 804 805 806 807 808 809 810
	*before = NULL;
	*after = NULL;

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

		if (sym->st_shndx >= SHN_LORESERVE)
			continue;
		symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
		if (strcmp(symsec, sec) != 0)
			continue;
811 812
		if (!is_valid_name(elf, sym))
			continue;
813 814 815 816 817
		if (sym->st_value <= addr) {
			if ((addr - sym->st_value) < beforediff) {
				beforediff = addr - sym->st_value;
				*before = sym;
			}
818
			else if ((addr - sym->st_value) == beforediff) {
819
				*before = sym;
820
			}
821 822 823 824 825 826 827
		}
		else
		{
			if ((sym->st_value - addr) < afterdiff) {
				afterdiff = sym->st_value - addr;
				*after = sym;
			}
828
			else if ((sym->st_value - addr) == afterdiff) {
829
				*after = sym;
830
			}
831 832 833 834 835 836 837
		}
	}
}

/**
 * Print a warning about a section mismatch.
 * Try to find symbols near it so user can find it.
838
 * Check whitelist before warning - it may be a false positive.
839 840 841 842
 **/
static void warn_sec_mismatch(const char *modname, const char *fromsec,
			      struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
{
843 844 845
	const char *refsymname = "";
	Elf_Sym *before, *after;
	Elf_Sym *refsym;
846 847 848 849 850
	Elf_Ehdr *hdr = elf->hdr;
	Elf_Shdr *sechdrs = elf->sechdrs;
	const char *secstrings = (void *)hdr +
				 sechdrs[hdr->e_shstrndx].sh_offset;
	const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
851

852 853
	find_symbols_between(elf, r.r_offset, fromsec, &before, &after);

854 855 856
	refsym = find_elf_symbol(elf, r.r_addend, sym);
	if (refsym && strlen(elf->strtab + refsym->st_name))
		refsymname = elf->strtab + refsym->st_name;
857 858

	/* check whitelist - we may ignore it */
859
	if (before &&
860
	    secref_whitelist(modname, secname, fromsec,
861
			     elf->strtab + before->st_name, refsymname))
862
		return;
863

864
	if (before && after) {
865 866 867 868
		warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
		     "(between '%s' and '%s')\n",
		     modname, fromsec, (unsigned long long)r.r_offset,
		     secname, refsymname,
869 870 871
		     elf->strtab + before->st_name,
		     elf->strtab + after->st_name);
	} else if (before) {
872 873 874 875 876
		warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
		     "(after '%s')\n",
		     modname, fromsec, (unsigned long long)r.r_offset,
		     secname, refsymname,
		     elf->strtab + before->st_name);
877
	} else if (after) {
878
		warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
879
		     "before '%s' (at offset -0x%llx)\n",
880 881 882
		     modname, fromsec, (unsigned long long)r.r_offset,
		     secname, refsymname,
		     elf->strtab + after->st_name);
883
	} else {
884 885 886
		warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
		     modname, fromsec, (unsigned long long)r.r_offset,
		     secname, refsymname);
887 888 889
	}
}

890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918
static unsigned int *reloc_location(struct elf_info *elf,
					   int rsection, Elf_Rela *r)
{
	Elf_Shdr *sechdrs = elf->sechdrs;
	int section = sechdrs[rsection].sh_info;

	return (void *)elf->hdr + sechdrs[section].sh_offset +
		(r->r_offset - sechdrs[section].sh_addr);
}

static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);
	unsigned int *location = reloc_location(elf, rsection, 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;
}

919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938
static int addend_arm_rel(struct elf_info *elf, int rsection, 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:
		/* From ARM ABI: ((S + A) | T) - P */
		r->r_addend = (int)(long)(elf->hdr + elf->sechdrs[rsection].sh_offset +
		                          (r->r_offset - elf->sechdrs[rsection].sh_addr));
		break;
	default:
		return 1;
	}
	return 0;
}

939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961
static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
{
	unsigned int r_typ = ELF_R_TYPE(r->r_info);
	unsigned int *location = reloc_location(elf, rsection, 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;
}

962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
/**
 * 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 intialized.
 * Likewise for modules used built-in the sections marked __exit
 * are discarded because __exit marked function are supposed to be called
 * only when a moduel is unloaded which never happes 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 section(const char*),
			  int section_ref_ok(const char *))
{
	int i;
	Elf_Sym  *sym;
	Elf_Ehdr *hdr = elf->hdr;
	Elf_Shdr *sechdrs = elf->sechdrs;
	const char *secstrings = (void *)hdr +
				 sechdrs[hdr->e_shstrndx].sh_offset;
985

986 987
	/* Walk through all sections */
	for (i = 0; i < hdr->e_shnum; i++) {
988 989 990
		const char *name = secstrings + sechdrs[i].sh_name;
		const char *secname;
		Elf_Rela r;
991
		unsigned int r_sym;
992
		/* We want to process only relocation sections and not .init */
993 994 995 996 997 998 999
		if (sechdrs[i].sh_type == SHT_RELA) {
			Elf_Rela *rela;
			Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
			Elf_Rela *stop  = (void*)start + sechdrs[i].sh_size;
			name += strlen(".rela");
			if (section_ref_ok(name))
				continue;
1000

1001 1002
			for (rela = start; rela < stop; rela++) {
				r.r_offset = TO_NATIVE(rela->r_offset);
1003 1004
#if KERNEL_ELFCLASS == ELFCLASS64
				if (hdr->e_machine == EM_MIPS) {
1005
					unsigned int r_typ;
1006 1007
					r_sym = ELF64_MIPS_R_SYM(rela->r_info);
					r_sym = TO_NATIVE(r_sym);
1008 1009
					r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
					r.r_info = ELF64_R_INFO(r_sym, r_typ);
1010 1011 1012 1013 1014 1015 1016 1017
				} 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
1018
				r.r_addend = TO_NATIVE(rela->r_addend);
1019
				sym = elf->symtab_start + r_sym;
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
				/* Skip special sections */
				if (sym->st_shndx >= SHN_LORESERVE)
					continue;

				secname = secstrings +
					sechdrs[sym->st_shndx].sh_name;
				if (section(secname))
					warn_sec_mismatch(modname, name,
							  elf, sym, r);
			}
		} else if (sechdrs[i].sh_type == SHT_REL) {
			Elf_Rel *rel;
			Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
			Elf_Rel *stop  = (void*)start + sechdrs[i].sh_size;
			name += strlen(".rel");
			if (section_ref_ok(name))
1036 1037
				continue;

1038 1039
			for (rel = start; rel < stop; rel++) {
				r.r_offset = TO_NATIVE(rel->r_offset);
1040 1041
#if KERNEL_ELFCLASS == ELFCLASS64
				if (hdr->e_machine == EM_MIPS) {
1042
					unsigned int r_typ;
1043 1044
					r_sym = ELF64_MIPS_R_SYM(rel->r_info);
					r_sym = TO_NATIVE(r_sym);
1045 1046
					r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
					r.r_info = ELF64_R_INFO(r_sym, r_typ);
1047 1048 1049 1050 1051 1052 1053 1054
				} 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
1055
				r.r_addend = 0;
1056 1057 1058 1059 1060
				switch (hdr->e_machine) {
				case EM_386:
					if (addend_386_rel(elf, i, &r))
						continue;
					break;
1061 1062 1063 1064
				case EM_ARM:
					if(addend_arm_rel(elf, i, &r))
						continue;
					break;
1065 1066 1067 1068 1069
				case EM_MIPS:
					if (addend_mips_rel(elf, i, &r))
						continue;
					break;
				}
1070
				sym = elf->symtab_start + r_sym;
1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
				/* Skip special sections */
				if (sym->st_shndx >= SHN_LORESERVE)
					continue;

				secname = secstrings +
					sechdrs[sym->st_shndx].sh_name;
				if (section(secname))
					warn_sec_mismatch(modname, name,
							  elf, sym, r);
			}
1081 1082 1083 1084
		}
	}
}

1085 1086 1087 1088 1089 1090 1091 1092 1093
/*
 * Identify sections from which references to either a
 * .init or a .exit section is OK.
 *
 * [OPD] Keith Ownes <kaos@sgi.com> commented:
 * For our future {in}sanity, add a comment that this is the ppc .opd
 * section, not the ia64 .opd section.
 * ia64 .opd should not point to discarded sections.
 * [.rodata] like for .init.text we ignore .rodata references -same reason
1094
 */
1095 1096 1097 1098 1099 1100 1101 1102 1103 1104
static int initexit_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
		"__bug_table",		/* used by powerpc for BUG() */
		"__ex_table",
		".altinstructions",
		".cranges",		/* used by sh64 */
		".fixup",
1105 1106
		".machvec",		/* ia64 + powerpc uses these */
		".machine.desc",
1107 1108 1109 1110 1111 1112
		".opd",			/* See comment [OPD] */
		".parainstructions",
		".pdr",
		".plt",			/* seen on ARCH=um build on x86_64. Harmless */
		".smp_locks",
		".stab",
A
Al Viro 已提交
1113
		".m68k_fixup",
1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142
		NULL
	};
	/* Start of section names */
	const char *namelist2[] = {
		".debug",
		".eh_frame",
		".note",		/* ignore ELF notes - may contain anything */
		".got",			/* powerpc - global offset table */
		".toc",			/* powerpc - table of contents */
		NULL
	};
	/* part of section name */
	const char *namelist3 [] = {
		".unwind",  /* Sample: IA_64.unwind.exit.text */
		NULL
	};

	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
	for (s = namelist2; *s; s++)
		if (strncmp(*s, name, strlen(*s)) == 0)
			return 1;
	for (s = namelist3; *s; s++)
		if (strstr(name, *s) != NULL)
			return 1;
	return 0;
}

1143

1144
/*
1145
 * Identify sections from which references to a .init section is OK.
1146
 *
1147 1148 1149 1150 1151
 * Unfortunately references to read only data that referenced .init
 * sections had to be excluded. Almost all of these are false
 * positives, they are created by gcc. The downside of excluding rodata
 * is that there really are some user references from rodata to
 * init code, e.g. drivers/video/vgacon.c:
1152
 *
1153 1154 1155 1156 1157
 * const struct consw vga_con = {
 *        con_startup:            vgacon_startup,
 *
 * where vgacon_startup is __init.  If you want to wade through the false
 * positives, take out the check for rodata.
1158
 */
1159 1160 1161 1162 1163
static int init_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
1164
		"__dbe_table",		/* MIPS generate these */
1165 1166
		"__ftr_fixup",		/* powerpc cpu feature fixup */
		"__fw_ftr_fixup",	/* powerpc firmware feature fixup */
1167 1168 1169 1170
		"__param",
		".data.rel.ro",		/* used by parisc64 */
		".init",
		".text.lock",
1171 1172 1173 1174 1175
		NULL
	};
	/* Start of section names */
	const char *namelist2[] = {
		".init.",
1176
		".pci_fixup",
1177
		".rodata",
1178 1179 1180
		NULL
	};

1181 1182 1183
	if (initexit_section_ref_ok(name))
		return 1;

1184 1185 1186
	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
1187
	for (s = namelist2; *s; s++)
1188 1189
		if (strncmp(*s, name, strlen(*s)) == 0)
			return 1;
1190 1191 1192 1193

	/* If section name ends with ".init" we allow references
	 * as is the case with .initcallN.init, .early_param.init, .taglist.init etc
	 */
1194 1195
	if (strrcmp(name, ".init") == 0)
		return 1;
1196 1197 1198 1199 1200
	return 0;
}

/*
 * Identify sections from which references to a .exit section is OK.
1201
 */
1202 1203 1204 1205 1206 1207
static int exit_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
		".exit.data",
1208 1209
		".exit.text",
		".exitcall.exit",
1210
		".rodata",
1211 1212
		NULL
	};
1213

1214 1215 1216
	if (initexit_section_ref_ok(name))
		return 1;

1217 1218 1219 1220 1221 1222
	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
	return 0;
}

1223
static void read_symbols(char *modname)
L
Linus Torvalds 已提交
1224 1225 1226
{
	const char *symname;
	char *version;
1227
	char *license;
L
Linus Torvalds 已提交
1228 1229 1230 1231
	struct module *mod;
	struct elf_info info = { };
	Elf_Sym *sym;

1232 1233
	if (!parse_elf(&info, modname))
		return;
L
Linus Torvalds 已提交
1234 1235 1236 1237 1238 1239 1240 1241 1242 1243

	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;
	}

1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255
	license = get_modinfo(info.modinfo, info.modinfo_len, "license");
	while (license) {
		if (license_is_gpl_compatible(license))
			mod->gpl_compatible = 1;
		else {
			mod->gpl_compatible = 0;
			break;
		}
		license = get_next_modinfo(info.modinfo, info.modinfo_len,
					   "license", license);
	}

L
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1256 1257 1258 1259 1260 1261
	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
		symname = info.strtab + sym->st_name;

		handle_modversions(mod, &info, sym, symname);
		handle_moddevtable(mod, &info, sym, symname);
	}
1262 1263 1264 1265
	if (is_vmlinux(modname) && vmlinux_section_warnings) {
		check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
		check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
	}
L
Linus Torvalds 已提交
1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290

	version = get_modinfo(info.modinfo, info.modinfo_len, "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 struct_module - 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("struct_module", 0, mod->unres);
}

#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 */

1291 1292
void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
						      const char *fmt, ...)
L
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1293 1294 1295 1296
{
	char tmp[SZ];
	int len;
	va_list ap;
1297

L
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	va_start(ap, fmt);
	len = vsnprintf(tmp, SZ, fmt, ap);
1300
	buf_write(buf, tmp, len);
L
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1301 1302 1303
	va_end(ap);
}

1304
void buf_write(struct buffer *buf, const char *s, int len)
L
Linus Torvalds 已提交
1305 1306
{
	if (buf->size - buf->pos < len) {
1307
		buf->size += len + SZ;
L
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1308 1309 1310 1311 1312 1313
		buf->p = realloc(buf->p, buf->size);
	}
	strncpy(buf->p + buf->pos, s, len);
	buf->pos += len;
}

1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355
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)
1356 1357 1358 1359
{
	struct symbol *s, *exp;

	for (s = mod->unres; s; s = s->next) {
A
Andrew Morton 已提交
1360
		const char *basename;
1361 1362 1363
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod)
			continue;
A
Andrew Morton 已提交
1364
		basename = strrchr(mod->name, '/');
1365 1366
		if (basename)
			basename++;
1367 1368 1369 1370 1371
		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);
1372 1373 1374
        }
}

1375 1376 1377 1378
/**
 * Header for the generated file
 **/
static void add_header(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1379 1380 1381 1382 1383 1384 1385 1386 1387
{
	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, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
	buf_printf(b, "\n");
	buf_printf(b, "struct module __this_module\n");
	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1388
	buf_printf(b, " .name = KBUILD_MODNAME,\n");
L
Linus Torvalds 已提交
1389 1390 1391 1392 1393 1394
	if (mod->has_init)
		buf_printf(b, " .init = init_module,\n");
	if (mod->has_cleanup)
		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
			      " .exit = cleanup_module,\n"
			      "#endif\n");
1395
	buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
L
Linus Torvalds 已提交
1396 1397 1398
	buf_printf(b, "};\n");
}

1399 1400 1401
/**
 * Record CRCs for unresolved symbols
 **/
1402
static int add_versions(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1403 1404
{
	struct symbol *s, *exp;
1405
	int err = 0;
L
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1406 1407 1408 1409

	for (s = mod->unres; s; s = s->next) {
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod) {
1410
			if (have_vmlinux && !s->weak) {
1411 1412 1413 1414 1415 1416 1417 1418
				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;
				}
1419
			}
L
Linus Torvalds 已提交
1420 1421 1422 1423 1424 1425 1426 1427
			continue;
		}
		s->module = exp->module;
		s->crc_valid = exp->crc_valid;
		s->crc = exp->crc;
	}

	if (!modversions)
1428
		return err;
L
Linus Torvalds 已提交
1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439

	buf_printf(b, "\n");
	buf_printf(b, "static const struct modversion_info ____versions[]\n");
	buf_printf(b, "__attribute_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) {
1440
			warn("\"%s\" [%s.ko] has no CRC!\n",
L
Linus Torvalds 已提交
1441 1442 1443 1444 1445 1446 1447
				s->name, mod->name);
			continue;
		}
		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
	}

	buf_printf(b, "};\n");
1448 1449

	return err;
L
Linus Torvalds 已提交
1450 1451
}

1452 1453
static void add_depends(struct buffer *b, struct module *mod,
			struct module *modules)
L
Linus Torvalds 已提交
1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468
{
	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, "__attribute_used__\n");
	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
	buf_printf(b, "\"depends=");
	for (s = mod->unres; s; s = s->next) {
1469
		const char *p;
L
Linus Torvalds 已提交
1470 1471 1472 1473 1474 1475 1476
		if (!s->module)
			continue;

		if (s->module->seen)
			continue;

		s->module->seen = 1;
1477 1478 1479 1480 1481
		if ((p = strrchr(s->module->name, '/')) != NULL)
			p++;
		else
			p = s->module->name;
		buf_printf(b, "%s%s", first ? "" : ",", p);
L
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1482 1483 1484 1485 1486
		first = 0;
	}
	buf_printf(b, "\";\n");
}

1487
static void add_srcversion(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1488 1489 1490 1491 1492 1493 1494 1495
{
	if (mod->srcversion[0]) {
		buf_printf(b, "\n");
		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
			   mod->srcversion);
	}
}

1496
static void write_if_changed(struct buffer *b, const char *fname)
L
Linus Torvalds 已提交
1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539
{
	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);
}

1540
/* parse Module.symvers file. line format:
S
Sam Ravnborg 已提交
1541
 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1542
 **/
1543
static void read_dump(const char *fname, unsigned int kernel)
L
Linus Torvalds 已提交
1544 1545 1546 1547 1548 1549 1550 1551 1552 1553
{
	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))) {
S
Sam Ravnborg 已提交
1554
		char *symname, *modname, *d, *export, *end;
L
Linus Torvalds 已提交
1555 1556
		unsigned int crc;
		struct module *mod;
1557
		struct symbol *s;
L
Linus Torvalds 已提交
1558 1559 1560 1561 1562 1563 1564

		if (!(symname = strchr(line, '\t')))
			goto fail;
		*symname++ = '\0';
		if (!(modname = strchr(symname, '\t')))
			goto fail;
		*modname++ = '\0';
1565
		if ((export = strchr(modname, '\t')) != NULL)
1566
			*export++ = '\0';
S
Sam Ravnborg 已提交
1567 1568
		if (export && ((end = strchr(export, '\t')) != NULL))
			*end = '\0';
L
Linus Torvalds 已提交
1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
		crc = strtoul(line, &d, 16);
		if (*symname == '\0' || *modname == '\0' || *d != '\0')
			goto fail;

		if (!(mod = find_module(modname))) {
			if (is_vmlinux(modname)) {
				have_vmlinux = 1;
			}
			mod = new_module(NOFAIL(strdup(modname)));
			mod->skip = 1;
		}
1580
		s = sym_add_exported(symname, mod, export_no(export));
1581 1582
		s->kernel    = kernel;
		s->preloaded = 1;
1583
		sym_update_crc(symname, mod, crc, export_no(export));
L
Linus Torvalds 已提交
1584 1585 1586 1587 1588 1589
	}
	return;
fail:
	fatal("parse error in symbol dump file\n");
}

1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601
/* 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;
}
1602

1603
static void write_dump(const char *fname)
L
Linus Torvalds 已提交
1604 1605 1606 1607 1608 1609 1610 1611
{
	struct buffer buf = { };
	struct symbol *symbol;
	int n;

	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
		symbol = symbolhash[n];
		while (symbol) {
1612
			if (dump_sym(symbol))
1613
				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1614
					symbol->crc, symbol->name,
1615 1616
					symbol->module->name,
					export_str(symbol->export));
L
Linus Torvalds 已提交
1617 1618 1619 1620 1621 1622
			symbol = symbol->next;
		}
	}
	write_if_changed(&buf, fname);
}

1623
int main(int argc, char **argv)
L
Linus Torvalds 已提交
1624 1625 1626 1627
{
	struct module *mod;
	struct buffer buf = { };
	char fname[SZ];
1628 1629
	char *kernel_read = NULL, *module_read = NULL;
	char *dump_write = NULL;
L
Linus Torvalds 已提交
1630
	int opt;
1631
	int err;
L
Linus Torvalds 已提交
1632

1633
	while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) {
L
Linus Torvalds 已提交
1634 1635
		switch(opt) {
			case 'i':
1636 1637 1638 1639 1640
				kernel_read = optarg;
				break;
			case 'I':
				module_read = optarg;
				external_module = 1;
L
Linus Torvalds 已提交
1641 1642 1643 1644 1645 1646 1647 1648 1649 1650
				break;
			case 'm':
				modversions = 1;
				break;
			case 'o':
				dump_write = optarg;
				break;
			case 'a':
				all_versions = 1;
				break;
1651 1652 1653
			case 's':
				vmlinux_section_warnings = 0;
				break;
1654 1655 1656
			case 'w':
				warn_unresolved = 1;
				break;
L
Linus Torvalds 已提交
1657 1658 1659 1660 1661
			default:
				exit(1);
		}
	}

1662 1663 1664 1665
	if (kernel_read)
		read_dump(kernel_read, 1);
	if (module_read)
		read_dump(module_read, 0);
L
Linus Torvalds 已提交
1666 1667 1668 1669 1670

	while (optind < argc) {
		read_symbols(argv[optind++]);
	}

1671 1672 1673
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;
1674
		check_exports(mod);
1675 1676
	}

1677 1678
	err = 0;

L
Linus Torvalds 已提交
1679 1680 1681 1682 1683 1684 1685
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;

		buf.pos = 0;

		add_header(&buf, mod);
1686
		err |= add_versions(&buf, mod);
L
Linus Torvalds 已提交
1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697
		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);

1698
	return err;
L
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1699
}