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/* Postprocess module symbol versions * * Copyright 2003       Kai Germaschewski * Copyright 2002-2004  Rusty Russell, IBM Corporation * * 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" /* 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; voidfatal(const char *fmt, ...){	va_list arglist; 	fprintf(stderr, "FATAL: "); 	va_start(arglist, fmt);	vfprintf(stderr, fmt, arglist);	va_end(arglist); 	exit(1);} voidwarn(const char *fmt, ...){	va_list arglist; 	fprintf(stderr, "WARNING: "); 	va_start(arglist, fmt);	vfprintf(stderr, fmt, arglist);	va_end(arglist);} 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; 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;} struct module *new_module(char *modname){	struct module *mod;	char *p, *s;		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;	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;	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 */ 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 */ voidnew_symbol(const char *name, struct module *module, unsigned int *crc){	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;	if (crc) {		new->crc = *crc;		new->crc_valid = 1;	}} 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;} /* Add an exported symbol - it may have already been added without a * CRC, in this case just update the CRC */voidadd_exported_symbol(const char *name, struct module *module, unsigned int *crc){	struct symbol *s = find_symbol(name); 	if (!s) {		new_symbol(name, module, crc);		return;	}	if (crc) {		s->crc = *crc;		s->crc_valid = 1;	}} void *grab_file(const char *filename, unsigned long *size){	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;} /*   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;} voidrelease_file(void *file, unsigned long size){	munmap(file, size);} voidparse_elf(struct elf_info *info, const char *filename){	unsigned int i;	Elf_Ehdr *hdr = info->hdr;	Elf_Shdr *sechdrs;	Elf_Sym  *sym; 	hdr = grab_file(filename, &info->size);	if (!hdr) {		perror(filename);		abort();	}	info->hdr = hdr;	if (info->size < sizeof(*hdr))		goto truncated; 	/* 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);	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);	}	/* Find symbol table. */	for (i = 1; i < hdr->e_shnum; i++) {		const char *secstrings			= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 		if (sechdrs[i].sh_offset > info->size)			goto truncated;		if (strcmp(secstrings+sechdrs[i].sh_name, ".modinfo") == 0) {			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;			info->modinfo_len = sechdrs[i].sh_size;		}		if (sechdrs[i].sh_type != SHT_SYMTAB)			continue; 		info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;		info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset 			                         + sechdrs[i].sh_size;		info->strtab       = (void *)hdr + 			             sechdrs[sechdrs[i].sh_link].sh_offset;	}	if (!info->symtab_start) {		fprintf(stderr, "modpost: %s no symtab?\n", filename);		abort();	}	/* 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);	}	return;  truncated:	fprintf(stderr, "modpost: %s is truncated.\n", filename);	abort();} voidparse_elf_finish(struct elf_info *info){	release_file(info->hdr, info->size);} #define CRC_PFX     "__crc_"#define KSYMTAB_PFX "__ksymtab_" voidhandle_modversions(struct module *mod, struct elf_info *info,		   Elf_Sym *sym, const char *symname){	unsigned int crc; 	switch (sym->st_shndx) {	case SHN_COMMON:		fprintf(stderr, "*** Warning: \"%s\" [%s] is COMMON symbol\n",			symname, mod->name);		break;	case SHN_ABS:		/* CRC'd symbol */		if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {			crc = (unsigned int) sym->st_value;			add_exported_symbol(symname + strlen(CRC_PFX),					    mod, &crc);		}		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;/* 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				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) {			add_exported_symbol(symname + strlen(KSYMTAB_PFX),					    mod, NULL);		}		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;	}} intis_vmlinux(const char *modname){	const char *myname; 	if ((myname = strrchr(modname, '/')))		myname++;	else		myname = modname; 	return strcmp(myname, "vmlinux") == 0;} /* 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_modinfo(void *modinfo, unsigned long modinfo_len,			 const char *tag){	char *p;	unsigned int taglen = strlen(tag);	unsigned long size = modinfo_len; 	for (p = modinfo; p; p = next_string(p, &size)) {		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')			return p + taglen + 1;	}	return NULL;} voidread_symbols(char *modname){	const char *symname;	char *version;	struct module *mod;	struct elf_info info = { };	Elf_Sym *sym; 	parse_elf(&info, modname); 	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)) {		unsigned int fake_crc = 0;		have_vmlinux = 1;		add_exported_symbol("struct_module", mod, &fake_crc);		mod->skip = 1;	} 	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);	} 	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 */

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