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linux_dsm_epyc7002/scripts/mod/modpost.c
Masahiro Yamada ac5100f543 modpost: add read_text_file() and get_line() helpers 
modpost uses grab_file() to open a file, but it is not suitable for
a text file because the mmap'ed file is not terminated by null byte.
Actually, I see some issues for the use of grab_file().

The new helper, read_text_file() loads the whole file content into a
malloc'ed buffer, and appends a null byte. Then, get_line() reads
each line.

To handle text files, I intend to replace as follows:

  grab_file()    -> read_text_file()
  get_new_line() -> get_line()

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06 23:38:12 +09:00

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/* 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 <elf.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <limits.h>
#include <stdbool.h>
#include <errno.h>
#include "modpost.h"
#include "../../include/linux/license.h"
/* Are we using CONFIG_MODVERSIONS? */
static int modversions = 0;
/* Warn about undefined symbols? (do so if we have vmlinux) */
static int have_vmlinux = 0;
/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
static int all_versions = 0;
/* If we are modposting external module set to 1 */
static int external_module = 0;
/* Warn about section mismatch in vmlinux if set to 1 */
static int vmlinux_section_warnings = 1;
/* Only warn about unresolved symbols */
static int warn_unresolved = 0;
/* How a symbol is exported */
static int sec_mismatch_count = 0;
static int sec_mismatch_fatal = 0;
/* ignore missing files */
static int ignore_missing_files;
/* If set to 1, only warn (instead of error) about missing ns imports */
static int allow_missing_ns_imports;
enum export {
export_plain, export_unused, export_gpl,
export_unused_gpl, export_gpl_future, export_unknown
};
/* In kernel, this size is defined in linux/module.h;
* here we use Elf_Addr instead of long for covering cross-compile
*/
#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
void __attribute__((format(printf, 2, 3)))
modpost_log(enum loglevel loglevel, const char *fmt, ...)
{
va_list arglist;
switch (loglevel) {
case LOG_WARN:
fprintf(stderr, "WARNING: ");
break;
case LOG_ERROR:
fprintf(stderr, "ERROR: ");
break;
case LOG_FATAL:
fprintf(stderr, "FATAL: ");
break;
default: /* invalid loglevel, ignore */
break;
}
fprintf(stderr, "modpost: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
if (loglevel == LOG_FATAL)
exit(1);
}
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("Memory allocation failure: %s.\n", expr);
return ptr;
}
char *read_text_file(const char *filename)
{
struct stat st;
size_t nbytes;
int fd;
char *buf;
fd = open(filename, O_RDONLY);
if (fd < 0) {
perror(filename);
exit(1);
}
if (fstat(fd, &st) < 0) {
perror(filename);
exit(1);
}
buf = NOFAIL(malloc(st.st_size + 1));
nbytes = st.st_size;
while (nbytes) {
ssize_t bytes_read;
bytes_read = read(fd, buf, nbytes);
if (bytes_read < 0) {
perror(filename);
exit(1);
}
nbytes -= bytes_read;
}
buf[st.st_size] = '\0';
close(fd);
return buf;
}
char *get_line(char **stringp)
{
/* do not return the unwanted extra line at EOF */
if (*stringp && **stringp == '\0')
return NULL;
return strsep(stringp, "\n");
}
/* A list of all modules we processed */
static struct module *modules;
static struct module *find_module(const char *modname)
{
struct module *mod;
for (mod = modules; mod; mod = mod->next)
if (strcmp(mod->name, modname) == 0)
break;
return mod;
}
static struct module *new_module(const char *modname)
{
struct module *mod;
char *p;
mod = NOFAIL(malloc(sizeof(*mod)));
memset(mod, 0, sizeof(*mod));
p = NOFAIL(strdup(modname));
/* strip trailing .o */
if (strends(p, ".o")) {
p[strlen(p) - 2] = '\0';
mod->is_dot_o = 1;
}
/* add to list */
mod->name = p;
mod->gpl_compatible = -1;
mod->next = modules;
modules = mod;
return mod;
}
/* A hash of all exported symbols,
* struct symbol is also used for lists of unresolved symbols */
#define SYMBOL_HASH_SIZE 1024
struct symbol {
struct symbol *next;
struct module *module;
unsigned int crc;
int crc_valid;
char *namespace;
unsigned int weak:1;
unsigned int is_static:1; /* 1 if symbol is not global */
enum export export; /* Type of export */
char name[];
};
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;
s->is_static = 1;
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;
hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
return symbolhash[hash];
}
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 bool contains_namespace(struct namespace_list *list,
const char *namespace)
{
for (; list; list = list->next)
if (!strcmp(list->namespace, namespace))
return true;
return false;
}
static void add_namespace(struct namespace_list **list, const char *namespace)
{
struct namespace_list *ns_entry;
if (!contains_namespace(*list, namespace)) {
ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
strlen(namespace) + 1));
strcpy(ns_entry->namespace, namespace);
ns_entry->next = *list;
*list = ns_entry;
}
}
static bool module_imports_namespace(struct module *module,
const char *namespace)
{
return contains_namespace(module->imported_namespaces, namespace);
}
static const struct {
const char *str;
enum export export;
} export_list[] = {
{ .str = "EXPORT_SYMBOL", .export = export_plain },
{ .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
{ .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
{ .str = "(unknown)", .export = export_unknown },
};
static const char *export_str(enum export ex)
{
return export_list[ex].str;
}
static enum export export_no(const char *s)
{
int i;
if (!s)
return export_unknown;
for (i = 0; export_list[i].export != export_unknown; i++) {
if (strcmp(export_list[i].str, s) == 0)
return export_list[i].export;
}
return export_unknown;
}
static void *sym_get_data_by_offset(const struct elf_info *info,
unsigned int secindex, unsigned long offset)
{
Elf_Shdr *sechdr = &info->sechdrs[secindex];
if (info->hdr->e_type != ET_REL)
offset -= sechdr->sh_addr;
return (void *)info->hdr + sechdr->sh_offset + offset;
}
static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
{
return sym_get_data_by_offset(info, get_secindex(info, sym),
sym->st_value);
}
static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
{
return sym_get_data_by_offset(info, info->secindex_strings,
sechdr->sh_name);
}
static const char *sec_name(const struct elf_info *info, int secindex)
{
return sech_name(info, &info->sechdrs[secindex]);
}
#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
{
const char *secname = sec_name(elf, sec);
if (strstarts(secname, "___ksymtab+"))
return export_plain;
else if (strstarts(secname, "___ksymtab_unused+"))
return export_unused;
else if (strstarts(secname, "___ksymtab_gpl+"))
return export_gpl;
else if (strstarts(secname, "___ksymtab_unused_gpl+"))
return export_unused_gpl;
else if (strstarts(secname, "___ksymtab_gpl_future+"))
return export_gpl_future;
else
return export_unknown;
}
static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
{
if (sec == elf->export_sec)
return export_plain;
else if (sec == elf->export_unused_sec)
return export_unused;
else if (sec == elf->export_gpl_sec)
return export_gpl;
else if (sec == elf->export_unused_gpl_sec)
return export_unused_gpl;
else if (sec == elf->export_gpl_future_sec)
return export_gpl_future;
else
return export_unknown;
}
static const char *namespace_from_kstrtabns(const struct elf_info *info,
const Elf_Sym *sym)
{
const char *value = sym_get_data(info, sym);
return value[0] ? value : NULL;
}
static void sym_update_namespace(const char *symname, const char *namespace)
{
struct symbol *s = find_symbol(symname);
/*
* That symbol should have been created earlier and thus this is
* actually an assertion.
*/
if (!s) {
merror("Could not update namespace(%s) for symbol %s\n",
namespace, symname);
return;
}
free(s->namespace);
s->namespace =
namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
}
/**
* 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 (!external_module || is_vmlinux(s->module->name) ||
s->module == mod) {
warn("%s: '%s' exported twice. Previous export was in %s%s\n",
mod->name, name, s->module->name,
is_vmlinux(s->module->name) ? "" : ".ko");
return s;
}
s->module = mod;
s->export = export;
return s;
}
static void sym_set_crc(const char *name, unsigned int crc)
{
struct symbol *s = find_symbol(name);
/*
* Ignore stand-alone __crc_*, which might be auto-generated symbols
* such as __*_veneer in ARM ELF.
*/
if (!s)
return;
s->crc = crc;
s->crc_valid = 1;
}
void *grab_file(const char *filename, unsigned long *size)
{
struct stat st;
void *map = MAP_FAILED;
int fd;
fd = open(filename, O_RDONLY);
if (fd < 0)
return NULL;
if (fstat(fd, &st))
goto failed;
*size = st.st_size;
map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
failed:
close(fd);
if (map == MAP_FAILED)
return NULL;
return map;
}
/**
* Return a copy of the next line in a mmap'ed file.
* spaces in the beginning of the line is trimmed away.
* Return a pointer to a static buffer.
**/
char *get_next_line(unsigned long *pos, void *file, unsigned long size)
{
static char line[4096];
int skip = 1;
size_t len = 0;
signed char *p = (signed char *)file + *pos;
char *s = line;
for (; *pos < size ; (*pos)++) {
if (skip && isspace(*p)) {
p++;
continue;
}
skip = 0;
if (*p != '\n' && (*pos < size)) {
len++;
*s++ = *p++;
if (len > 4095)
break; /* Too long, stop */
} else {
/* End of string */
*s = '\0';
return line;
}
}
/* End of buffer */
return NULL;
}
void release_file(void *file, unsigned long size)
{
munmap(file, size);
}
static int parse_elf(struct elf_info *info, const char *filename)
{
unsigned int i;
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
Elf_Sym *sym;
const char *secstrings;
unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
hdr = grab_file(filename, &info->size);
if (!hdr) {
if (ignore_missing_files) {
fprintf(stderr, "%s: %s (ignored)\n", filename,
strerror(errno));
return 0;
}
perror(filename);
exit(1);
}
info->hdr = hdr;
if (info->size < sizeof(*hdr)) {
/* file too small, assume this is an empty .o file */
return 0;
}
/* Is this a valid ELF file? */
if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
(hdr->e_ident[EI_MAG1] != ELFMAG1) ||
(hdr->e_ident[EI_MAG2] != ELFMAG2) ||
(hdr->e_ident[EI_MAG3] != ELFMAG3)) {
/* Not an ELF file - silently ignore it */
return 0;
}
/* Fix endianness in ELF header */
hdr->e_type = TO_NATIVE(hdr->e_type);
hdr->e_machine = TO_NATIVE(hdr->e_machine);
hdr->e_version = TO_NATIVE(hdr->e_version);
hdr->e_entry = TO_NATIVE(hdr->e_entry);
hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
hdr->e_flags = TO_NATIVE(hdr->e_flags);
hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
sechdrs = (void *)hdr + hdr->e_shoff;
info->sechdrs = sechdrs;
/* Check if file offset is correct */
if (hdr->e_shoff > info->size) {
fatal("section header offset=%lu in file '%s' is bigger than "
"filesize=%lu\n", (unsigned long)hdr->e_shoff,
filename, info->size);
return 0;
}
if (hdr->e_shnum == SHN_UNDEF) {
/*
* There are more than 64k sections,
* read count from .sh_size.
*/
info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
}
else {
info->num_sections = hdr->e_shnum;
}
if (hdr->e_shstrndx == SHN_XINDEX) {
info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
}
else {
info->secindex_strings = hdr->e_shstrndx;
}
/* Fix endianness in section headers */
for (i = 0; i < info->num_sections; i++) {
sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
}
/* Find symbol table. */
secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
for (i = 1; i < info->num_sections; i++) {
const char *secname;
int nobits = sechdrs[i].sh_type == SHT_NOBITS;
if (!nobits && sechdrs[i].sh_offset > info->size) {
fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
"sizeof(*hrd)=%zu\n", filename,
(unsigned long)sechdrs[i].sh_offset,
sizeof(*hdr));
return 0;
}
secname = secstrings + sechdrs[i].sh_name;
if (strcmp(secname, ".modinfo") == 0) {
if (nobits)
fatal("%s has NOBITS .modinfo\n", filename);
info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
info->modinfo_len = sechdrs[i].sh_size;
} else if (strcmp(secname, "__ksymtab") == 0)
info->export_sec = i;
else if (strcmp(secname, "__ksymtab_unused") == 0)
info->export_unused_sec = i;
else if (strcmp(secname, "__ksymtab_gpl") == 0)
info->export_gpl_sec = i;
else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
info->export_unused_gpl_sec = i;
else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
info->export_gpl_future_sec = i;
if (sechdrs[i].sh_type == SHT_SYMTAB) {
unsigned int sh_link_idx;
symtab_idx = i;
info->symtab_start = (void *)hdr +
sechdrs[i].sh_offset;
info->symtab_stop = (void *)hdr +
sechdrs[i].sh_offset + sechdrs[i].sh_size;
sh_link_idx = sechdrs[i].sh_link;
info->strtab = (void *)hdr +
sechdrs[sh_link_idx].sh_offset;
}
/* 32bit section no. table? ("more than 64k sections") */
if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
symtab_shndx_idx = i;
info->symtab_shndx_start = (void *)hdr +
sechdrs[i].sh_offset;
info->symtab_shndx_stop = (void *)hdr +
sechdrs[i].sh_offset + sechdrs[i].sh_size;
}
}
if (!info->symtab_start)
fatal("%s has no symtab?\n", filename);
/* Fix endianness in symbols */
for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
sym->st_shndx = TO_NATIVE(sym->st_shndx);
sym->st_name = TO_NATIVE(sym->st_name);
sym->st_value = TO_NATIVE(sym->st_value);
sym->st_size = TO_NATIVE(sym->st_size);
}
if (symtab_shndx_idx != ~0U) {
Elf32_Word *p;
if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
filename, sechdrs[symtab_shndx_idx].sh_link,
symtab_idx);
/* Fix endianness */
for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
p++)
*p = TO_NATIVE(*p);
}
return 1;
}
static void parse_elf_finish(struct elf_info *info)
{
release_file(info->hdr, info->size);
}
static int ignore_undef_symbol(struct elf_info *info, const char *symname)
{
/* ignore __this_module, it will be resolved shortly */
if (strcmp(symname, "__this_module") == 0)
return 1;
/* ignore global offset table */
if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
return 1;
if (info->hdr->e_machine == EM_PPC)
/* Special register function linked on all modules during final link of .ko */
if (strstarts(symname, "_restgpr_") ||
strstarts(symname, "_savegpr_") ||
strstarts(symname, "_rest32gpr_") ||
strstarts(symname, "_save32gpr_") ||
strstarts(symname, "_restvr_") ||
strstarts(symname, "_savevr_"))
return 1;
if (info->hdr->e_machine == EM_PPC64)
/* Special register function linked on all modules during final link of .ko */
if (strstarts(symname, "_restgpr0_") ||
strstarts(symname, "_savegpr0_") ||
strstarts(symname, "_restvr_") ||
strstarts(symname, "_savevr_") ||
strcmp(symname, ".TOC.") == 0)
return 1;
/* Do not ignore this symbol */
return 0;
}
static void handle_modversion(const struct module *mod,
const struct elf_info *info,
const Elf_Sym *sym, const char *symname)
{
unsigned int crc;
if (sym->st_shndx == SHN_UNDEF) {
warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
symname, mod->name, is_vmlinux(mod->name) ? "":".ko");
return;
}
if (sym->st_shndx == SHN_ABS) {
crc = sym->st_value;
} else {
unsigned int *crcp;
/* symbol points to the CRC in the ELF object */
crcp = sym_get_data(info, sym);
crc = TO_NATIVE(*crcp);
}
sym_set_crc(symname, crc);
}
static void handle_symbol(struct module *mod, struct elf_info *info,
const Elf_Sym *sym, const char *symname)
{
enum export export;
const char *name;
if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
strstarts(symname, "__ksymtab"))
export = export_from_secname(info, get_secindex(info, sym));
else
export = export_from_sec(info, get_secindex(info, sym));
switch (sym->st_shndx) {
case SHN_COMMON:
if (strstarts(symname, "__gnu_lto_")) {
/* Should warn here, but modpost runs before the linker */
} else
warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
break;
case SHN_UNDEF:
/* undefined symbol */
if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
ELF_ST_BIND(sym->st_info) != STB_WEAK)
break;
if (ignore_undef_symbol(info, symname))
break;
if (info->hdr->e_machine == EM_SPARC ||
info->hdr->e_machine == EM_SPARCV9) {
/* Ignore register directives. */
if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
break;
if (symname[0] == '.') {
char *munged = NOFAIL(strdup(symname));
munged[0] = '_';
munged[1] = toupper(munged[1]);
symname = munged;
}
}
mod->unres = alloc_symbol(symname,
ELF_ST_BIND(sym->st_info) == STB_WEAK,
mod->unres);
break;
default:
/* All exported symbols */
if (strstarts(symname, "__ksymtab_")) {
name = symname + strlen("__ksymtab_");
sym_add_exported(name, mod, export);
}
if (strcmp(symname, "init_module") == 0)
mod->has_init = 1;
if (strcmp(symname, "cleanup_module") == 0)
mod->has_cleanup = 1;
break;
}
}
/**
* Parse tag=value strings from .modinfo section
**/
static char *next_string(char *string, unsigned long *secsize)
{
/* Skip non-zero chars */
while (string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
/* Skip any zero padding. */
while (!string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
return string;
}
static char *get_next_modinfo(struct elf_info *info, const char *tag,
char *prev)
{
char *p;
unsigned int taglen = strlen(tag);
char *modinfo = info->modinfo;
unsigned long size = info->modinfo_len;
if (prev) {
size -= prev - modinfo;
modinfo = next_string(prev, &size);
}
for (p = modinfo; p; p = next_string(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
return NULL;
}
static char *get_modinfo(struct elf_info *info, const char *tag)
{
return get_next_modinfo(info, tag, NULL);
}
/**
* Test if string s ends in string sub
* return 0 if match
**/
static int strrcmp(const char *s, const char *sub)
{
int slen, sublen;
if (!s || !sub)
return 1;
slen = strlen(s);
sublen = strlen(sub);
if ((slen == 0) || (sublen == 0))
return 1;
if (sublen > slen)
return 1;
return memcmp(s + slen - sublen, sub, sublen);
}
static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
{
if (sym)
return elf->strtab + sym->st_name;
else
return "(unknown)";
}
/* The pattern is an array of simple patterns.
* "foo" will match an exact string equal to "foo"
* "*foo" will match a string that ends with "foo"
* "foo*" will match a string that begins with "foo"
* "*foo*" will match a string that contains "foo"
*/
static int match(const char *sym, const char * const pat[])
{
const char *p;
while (*pat) {
p = *pat++;
const char *endp = p + strlen(p) - 1;
/* "*foo*" */
if (*p == '*' && *endp == '*') {
char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
char *here = strstr(sym, bare);
free(bare);
if (here != NULL)
return 1;
}
/* "*foo" */
else if (*p == '*') {
if (strrcmp(sym, p + 1) == 0)
return 1;
}
/* "foo*" */
else if (*endp == '*') {
if (strncmp(sym, p, strlen(p) - 1) == 0)
return 1;
}
/* no wildcards */
else {
if (strcmp(p, sym) == 0)
return 1;
}
}
/* no match */
return 0;
}
/* sections that we do not want to do full section mismatch check on */
static const char *const section_white_list[] =
{
".comment*",
".debug*",
".cranges", /* sh64 */
".zdebug*", /* Compressed debug sections. */
".GCC.command.line", /* record-gcc-switches */
".mdebug*", /* alpha, score, mips etc. */
".pdr", /* alpha, score, mips etc. */
".stab*",
".note*",
".got*",
".toc*",
".xt.prop", /* xtensa */
".xt.lit", /* xtensa */
".arcextmap*", /* arc */
".gnu.linkonce.arcext*", /* arc : modules */
".cmem*", /* EZchip */
".fmt_slot*", /* EZchip */
".gnu.lto*",
".discard.*",
NULL
};
/*
* This is used to find sections missing the SHF_ALLOC flag.
* The cause of this is often a section specified in assembler
* without "ax" / "aw".
*/
static void check_section(const char *modname, struct elf_info *elf,
Elf_Shdr *sechdr)
{
const char *sec = sech_name(elf, sechdr);
if (sechdr->sh_type == SHT_PROGBITS &&
!(sechdr->sh_flags & SHF_ALLOC) &&
!match(sec, section_white_list)) {
warn("%s (%s): unexpected non-allocatable section.\n"
"Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
"Note that for example <linux/init.h> contains\n"
"section definitions for use in .S files.\n\n",
modname, sec);
}
}
#define ALL_INIT_DATA_SECTIONS \
".init.setup", ".init.rodata", ".meminit.rodata", \
".init.data", ".meminit.data"
#define ALL_EXIT_DATA_SECTIONS \
".exit.data", ".memexit.data"
#define ALL_INIT_TEXT_SECTIONS \
".init.text", ".meminit.text"
#define ALL_EXIT_TEXT_SECTIONS \
".exit.text", ".memexit.text"
#define ALL_PCI_INIT_SECTIONS \
".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
".pci_fixup_enable", ".pci_fixup_resume", \
".pci_fixup_resume_early", ".pci_fixup_suspend"
#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
#define DATA_SECTIONS ".data", ".data.rel"
#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
".kprobes.text", ".cpuidle.text"
#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
".fixup", ".entry.text", ".exception.text", ".text.*", \
".coldtext"
#define INIT_SECTIONS ".init.*"
#define MEM_INIT_SECTIONS ".meminit.*"
#define EXIT_SECTIONS ".exit.*"
#define MEM_EXIT_SECTIONS ".memexit.*"
#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
TEXT_SECTIONS, OTHER_TEXT_SECTIONS
/* init data sections */
static const char *const init_data_sections[] =
{ ALL_INIT_DATA_SECTIONS, NULL };
/* all init sections */
static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
/* All init and exit sections (code + data) */
static const char *const init_exit_sections[] =
{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
/* all text sections */
static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
/* data section */
static const char *const data_sections[] = { DATA_SECTIONS, NULL };
/* symbols in .data that may refer to init/exit sections */
#define DEFAULT_SYMBOL_WHITE_LIST \
"*driver", \
"*_template", /* scsi uses *_template a lot */ \
"*_timer", /* arm uses ops structures named _timer a lot */ \
"*_sht", /* scsi also used *_sht to some extent */ \
"*_ops", \
"*_probe", \
"*_probe_one", \
"*_console"
static const char *const head_sections[] = { ".head.text*", NULL };
static const char *const linker_symbols[] =
{ "__init_begin", "_sinittext", "_einittext", NULL };
static const char *const optim_symbols[] = { "*.constprop.*", NULL };
enum mismatch {
TEXT_TO_ANY_INIT,
DATA_TO_ANY_INIT,
TEXT_TO_ANY_EXIT,
DATA_TO_ANY_EXIT,
XXXINIT_TO_SOME_INIT,
XXXEXIT_TO_SOME_EXIT,
ANY_INIT_TO_ANY_EXIT,
ANY_EXIT_TO_ANY_INIT,
EXPORT_TO_INIT_EXIT,
EXTABLE_TO_NON_TEXT,
};
/**
* Describe how to match sections on different criterias:
*
* @fromsec: Array of sections to be matched.
*
* @bad_tosec: Relocations applied to a section in @fromsec to a section in
* this array is forbidden (black-list). Can be empty.
*
* @good_tosec: Relocations applied to a section in @fromsec must be
* targetting sections in this array (white-list). Can be empty.
*
* @mismatch: Type of mismatch.
*
* @symbol_white_list: Do not match a relocation to a symbol in this list
* even if it is targetting a section in @bad_to_sec.
*
* @handler: Specific handler to call when a match is found. If NULL,
* default_mismatch_handler() will be called.
*
*/
struct sectioncheck {
const char *fromsec[20];
const char *bad_tosec[20];
const char *good_tosec[20];
enum mismatch mismatch;
const char *symbol_white_list[20];
void (*handler)(const char *modname, struct elf_info *elf,
const struct sectioncheck* const mismatch,
Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
};
static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
const struct sectioncheck* const mismatch,
Elf_Rela *r, Elf_Sym *sym,
const char *fromsec);
static const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
* normal code and data
*/
{
.fromsec = { TEXT_SECTIONS, NULL },
.bad_tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = TEXT_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
.bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
.bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_INIT,
.symbol_white_list = {
"*_template", "*_timer", "*_sht", "*_ops",
"*_probe", "*_probe_one", "*_console", NULL
},
},
{
.fromsec = { TEXT_SECTIONS, NULL },
.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = TEXT_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference init code/data from meminit code/data */
{
.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
.bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = XXXINIT_TO_SOME_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference exit code/data from memexit code/data */
{
.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
.bad_tosec = { EXIT_SECTIONS, NULL },
.mismatch = XXXEXIT_TO_SOME_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not use exit code/data from init code */
{
.fromsec = { ALL_INIT_SECTIONS, NULL },
.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not use init code/data from exit code */
{
.fromsec = { ALL_EXIT_SECTIONS, NULL },
.bad_tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = ANY_EXIT_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
.bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
.symbol_white_list = { NULL },
},
/* Do not export init/exit functions or data */
{
.fromsec = { "__ksymtab*", NULL },
.bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
.mismatch = EXPORT_TO_INIT_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { "__ex_table", NULL },
/* If you're adding any new black-listed sections in here, consider
* adding a special 'printer' for them in scripts/check_extable.
*/
.bad_tosec = { ".altinstr_replacement", NULL },
.good_tosec = {ALL_TEXT_SECTIONS , NULL},
.mismatch = EXTABLE_TO_NON_TEXT,
.handler = extable_mismatch_handler,
}
};
static const struct sectioncheck *section_mismatch(
const char *fromsec, const char *tosec)
{
int i;
int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
const struct sectioncheck *check = &sectioncheck[0];
/*
* The target section could be the SHT_NUL section when we're
* handling relocations to un-resolved symbols, trying to match it
* doesn't make much sense and causes build failures on parisc
* architectures.
*/
if (*tosec == '\0')
return NULL;
for (i = 0; i < elems; i++) {
if (match(fromsec, check->fromsec)) {
if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
return check;
if (check->good_tosec[0] && !match(tosec, check->good_tosec))
return check;
}
check++;
}
return NULL;
}
/**
* Whitelist to allow certain references to pass with no warning.
*
* Pattern 1:
* If a module parameter is declared __initdata and permissions=0
* then this is legal despite the warning generated.
* We cannot see value of permissions here, so just ignore
* this pattern.
* The pattern is identified by:
* tosec = .init.data
* fromsec = .data*
* atsym =__param*
*
* Pattern 1a:
* module_param_call() ops can refer to __init set function if permissions=0
* The pattern is identified by:
* tosec = .init.text
* fromsec = .data*
* atsym = __param_ops_*
*
* Pattern 2:
* Many drivers utilise a *driver container with references to
* add, remove, probe functions etc.
* the pattern is identified by:
* tosec = init or exit section
* fromsec = data section
* atsym = *driver, *_template, *_sht, *_ops, *_probe,
* *probe_one, *_console, *_timer
*
* Pattern 3:
* Whitelist all references from .head.text to any init section
*
* Pattern 4:
* Some symbols belong to init section but still it is ok to reference
* these from non-init sections as these symbols don't have any memory
* allocated for them and symbol address and value are same. So even
* if init section is freed, its ok to reference those symbols.
* For ex. symbols marking the init section boundaries.
* This pattern is identified by
* refsymname = __init_begin, _sinittext, _einittext
*
* Pattern 5:
* GCC may optimize static inlines when fed constant arg(s) resulting
* in functions like cpumask_empty() -- generating an associated symbol
* cpumask_empty.constprop.3 that appears in the audit. If the const that
* is passed in comes from __init, like say nmi_ipi_mask, we get a
* meaningless section warning. May need to add isra symbols too...
* This pattern is identified by
* tosec = init section
* fromsec = text section
* refsymname = *.constprop.*
*
* Pattern 6:
* Hide section mismatch warnings for ELF local symbols. The goal
* is to eliminate false positive modpost warnings caused by
* compiler-generated ELF local symbol names such as ".LANCHOR1".
* Autogenerated symbol names bypass modpost's "Pattern 2"
* whitelisting, which relies on pattern-matching against symbol
* names to work. (One situation where gcc can autogenerate ELF
* local symbols is when "-fsection-anchors" is used.)
**/
static int secref_whitelist(const struct sectioncheck *mismatch,
const char *fromsec, const char *fromsym,
const char *tosec, const char *tosym)
{
/* Check for pattern 1 */
if (match(tosec, init_data_sections) &&
match(fromsec, data_sections) &&
strstarts(fromsym, "__param"))
return 0;
/* Check for pattern 1a */
if (strcmp(tosec, ".init.text") == 0 &&
match(fromsec, data_sections) &&
strstarts(fromsym, "__param_ops_"))
return 0;
/* Check for pattern 2 */
if (match(tosec, init_exit_sections) &&
match(fromsec, data_sections) &&
match(fromsym, mismatch->symbol_white_list))
return 0;
/* Check for pattern 3 */
if (match(fromsec, head_sections) &&
match(tosec, init_sections))
return 0;
/* Check for pattern 4 */
if (match(tosym, linker_symbols))
return 0;
/* Check for pattern 5 */
if (match(fromsec, text_sections) &&
match(tosec, init_sections) &&
match(fromsym, optim_symbols))
return 0;
/* Check for pattern 6 */
if (strstarts(fromsym, ".L"))
return 0;
return 1;
}
static inline int is_arm_mapping_symbol(const char *str)
{
return str[0] == '$' && strchr("axtd", str[1])
&& (str[2] == '\0' || str[2] == '.');
}
/*
* If there's no name there, ignore it; likewise, ignore it if it's
* one of the magic symbols emitted used by current ARM tools.
*
* Otherwise if find_symbols_between() returns those symbols, they'll
* fail the whitelist tests and cause lots of false alarms ... fixable
* only by merging __exit and __init sections into __text, bloating
* the kernel (which is especially evil on embedded platforms).
*/
static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
{
const char *name = elf->strtab + sym->st_name;
if (!name || !strlen(name))
return 0;
return !is_arm_mapping_symbol(name);
}
/**
* Find symbol based on relocation record info.
* In some cases the symbol supplied is a valid symbol so
* return refsym. If st_name != 0 we assume this is a valid symbol.
* In other cases the symbol needs to be looked up in the symbol table
* based on section and address.
* **/
static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
Elf_Sym *relsym)
{
Elf_Sym *sym;
Elf_Sym *near = NULL;
Elf64_Sword distance = 20;
Elf64_Sword d;
unsigned int relsym_secindex;
if (relsym->st_name != 0)
return relsym;
relsym_secindex = get_secindex(elf, relsym);
for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
if (get_secindex(elf, sym) != relsym_secindex)
continue;
if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
continue;
if (!is_valid_name(elf, sym))
continue;
if (sym->st_value == addr)
return sym;
/* Find a symbol nearby - addr are maybe negative */
d = sym->st_value - addr;
if (d < 0)
d = addr - sym->st_value;
if (d < distance) {
distance = d;
near = sym;
}
}
/* We need a close match */
if (distance < 20)
return near;
else
return NULL;
}
/*
* Find symbols before or equal addr and after addr - in the section sec.
* If we find two symbols with equal offset prefer one with a valid name.
* The ELF format may have a better way to detect what type of symbol
* it is, but this works for now.
**/
static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
const char *sec)
{
Elf_Sym *sym;
Elf_Sym *near = NULL;
Elf_Addr distance = ~0;
for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
const char *symsec;
if (is_shndx_special(sym->st_shndx))
continue;
symsec = sec_name(elf, get_secindex(elf, sym));
if (strcmp(symsec, sec) != 0)
continue;
if (!is_valid_name(elf, sym))
continue;
if (sym->st_value <= addr) {
if ((addr - sym->st_value) < distance) {
distance = addr - sym->st_value;
near = sym;
} else if ((addr - sym->st_value) == distance) {
near = sym;
}
}
}
return near;
}
/*
* Convert a section name to the function/data attribute
* .init.text => __init
* .memexitconst => __memconst
* etc.
*
* The memory of returned value has been allocated on a heap. The user of this
* method should free it after usage.
*/
static char *sec2annotation(const char *s)
{
if (match(s, init_exit_sections)) {
char *p = NOFAIL(malloc(20));
char *r = p;
*p++ = '_';
*p++ = '_';
if (*s == '.')
s++;
while (*s && *s != '.')
*p++ = *s++;
*p = '\0';
if (*s == '.')
s++;
if (strstr(s, "rodata") != NULL)
strcat(p, "const ");
else if (strstr(s, "data") != NULL)
strcat(p, "data ");
else
strcat(p, " ");
return r;
} else {
return NOFAIL(strdup(""));
}
}
static int is_function(Elf_Sym *sym)
{
if (sym)
return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
else
return -1;
}
static void print_section_list(const char * const list[20])
{
const char *const *s = list;
while (*s) {
fprintf(stderr, "%s", *s);
s++;
if (*s)
fprintf(stderr, ", ");
}
fprintf(stderr, "\n");
}
static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
{
switch (is_func) {
case 0: *name = "variable"; *name_p = ""; break;
case 1: *name = "function"; *name_p = "()"; break;
default: *name = "(unknown reference)"; *name_p = ""; break;
}
}
/*
* Print a warning about a section mismatch.
* Try to find symbols near it so user can find it.
* Check whitelist before warning - it may be a false positive.
*/
static void report_sec_mismatch(const char *modname,
const struct sectioncheck *mismatch,
const char *fromsec,
unsigned long long fromaddr,
const char *fromsym,
int from_is_func,
const char *tosec, const char *tosym,
int to_is_func)
{
const char *from, *from_p;
const char *to, *to_p;
char *prl_from;
char *prl_to;
sec_mismatch_count++;
get_pretty_name(from_is_func, &from, &from_p);
get_pretty_name(to_is_func, &to, &to_p);
warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
"to the %s %s:%s%s\n",
modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
tosym, to_p);
switch (mismatch->mismatch) {
case TEXT_TO_ANY_INIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The function %s%s() references\n"
"the %s %s%s%s.\n"
"This is often because %s lacks a %s\n"
"annotation or the annotation of %s is wrong.\n",
prl_from, fromsym,
to, prl_to, tosym, to_p,
fromsym, prl_to, tosym);
free(prl_from);
free(prl_to);
break;
case DATA_TO_ANY_INIT: {
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The variable %s references\n"
"the %s %s%s%s\n"
"If the reference is valid then annotate the\n"
"variable with __init* or __refdata (see linux/init.h) "
"or name the variable:\n",
fromsym, to, prl_to, tosym, to_p);
print_section_list(mismatch->symbol_white_list);
free(prl_to);
break;
}
case TEXT_TO_ANY_EXIT:
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The function %s() references a %s in an exit section.\n"
"Often the %s %s%s has valid usage outside the exit section\n"
"and the fix is to remove the %sannotation of %s.\n",
fromsym, to, to, tosym, to_p, prl_to, tosym);
free(prl_to);
break;
case DATA_TO_ANY_EXIT: {
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The variable %s references\n"
"the %s %s%s%s\n"
"If the reference is valid then annotate the\n"
"variable with __exit* (see linux/init.h) or "
"name the variable:\n",
fromsym, to, prl_to, tosym, to_p);
print_section_list(mismatch->symbol_white_list);
free(prl_to);
break;
}
case XXXINIT_TO_SOME_INIT:
case XXXEXIT_TO_SOME_EXIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The %s %s%s%s references\n"
"a %s %s%s%s.\n"
"If %s is only used by %s then\n"
"annotate %s with a matching annotation.\n",
from, prl_from, fromsym, from_p,
to, prl_to, tosym, to_p,
tosym, fromsym, tosym);
free(prl_from);
free(prl_to);
break;
case ANY_INIT_TO_ANY_EXIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The %s %s%s%s references\n"
"a %s %s%s%s.\n"
"This is often seen when error handling "
"in the init function\n"
"uses functionality in the exit path.\n"
"The fix is often to remove the %sannotation of\n"
"%s%s so it may be used outside an exit section.\n",
from, prl_from, fromsym, from_p,
to, prl_to, tosym, to_p,
prl_to, tosym, to_p);
free(prl_from);
free(prl_to);
break;
case ANY_EXIT_TO_ANY_INIT:
prl_from = sec2annotation(fromsec);
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The %s %s%s%s references\n"
"a %s %s%s%s.\n"
"This is often seen when error handling "
"in the exit function\n"
"uses functionality in the init path.\n"
"The fix is often to remove the %sannotation of\n"
"%s%s so it may be used outside an init section.\n",
from, prl_from, fromsym, from_p,
to, prl_to, tosym, to_p,
prl_to, tosym, to_p);
free(prl_from);
free(prl_to);
break;
case EXPORT_TO_INIT_EXIT:
prl_to = sec2annotation(tosec);
fprintf(stderr,
"The symbol %s is exported and annotated %s\n"
"Fix this by removing the %sannotation of %s "
"or drop the export.\n",
tosym, prl_to, prl_to, tosym);
free(prl_to);
break;
case EXTABLE_TO_NON_TEXT:
fatal("There's a special handler for this mismatch type, "
"we should never get here.");
break;
}
fprintf(stderr, "\n");
}
static void default_mismatch_handler(const char *modname, struct elf_info *elf,
const struct sectioncheck* const mismatch,
Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
{
const char *tosec;
Elf_Sym *to;
Elf_Sym *from;
const char *tosym;
const char *fromsym;
from = find_elf_symbol2(elf, r->r_offset, fromsec);
fromsym = sym_name(elf, from);
if (strstarts(fromsym, "reference___initcall"))
return;
tosec = sec_name(elf, get_secindex(elf, sym));
to = find_elf_symbol(elf, r->r_addend, sym);
tosym = sym_name(elf, to);
/* check whitelist - we may ignore it */
if (secref_whitelist(mismatch,
fromsec, fromsym, tosec, tosym)) {
report_sec_mismatch(modname, mismatch,
fromsec, r->r_offset, fromsym,
is_function(from), tosec, tosym,
is_function(to));
}
}
static int is_executable_section(struct elf_info* elf, unsigned int section_index)
{
if (section_index > elf->num_sections)
fatal("section_index is outside elf->num_sections!\n");
return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
}
/*
* We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
* to know the sizeof(struct exception_table_entry) for the target architecture.
*/
static unsigned int extable_entry_size = 0;
static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
{
/*
* If we're currently checking the second relocation within __ex_table,
* that relocation offset tells us the offsetof(struct
* exception_table_entry, fixup) which is equal to sizeof(struct
* exception_table_entry) divided by two. We use that to our advantage
* since there's no portable way to get that size as every architecture
* seems to go with different sized types. Not pretty but better than
* hard-coding the size for every architecture..
*/
if (!extable_entry_size)
extable_entry_size = r->r_offset * 2;
}
static inline bool is_extable_fault_address(Elf_Rela *r)
{
/*
* extable_entry_size is only discovered after we've handled the
* _second_ relocation in __ex_table, so only abort when we're not
* handling the first reloc and extable_entry_size is zero.
*/
if (r->r_offset && extable_entry_size == 0)
fatal("extable_entry size hasn't been discovered!\n");
return ((r->r_offset == 0) ||
(r->r_offset % extable_entry_size == 0));
}
#define is_second_extable_reloc(Start, Cur, Sec) \
(((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
static void report_extable_warnings(const char* modname, struct elf_info* elf,
const struct sectioncheck* const mismatch,
Elf_Rela* r, Elf_Sym* sym,
const char* fromsec, const char* tosec)
{
Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
const char* fromsym_name = sym_name(elf, fromsym);
Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
const char* tosym_name = sym_name(elf, tosym);
const char* from_pretty_name;
const char* from_pretty_name_p;
const char* to_pretty_name;
const char* to_pretty_name_p;
get_pretty_name(is_function(fromsym),
&from_pretty_name, &from_pretty_name_p);
get_pretty_name(is_function(tosym),
&to_pretty_name, &to_pretty_name_p);
warn("%s(%s+0x%lx): Section mismatch in reference"
" from the %s %s%s to the %s %s:%s%s\n",
modname, fromsec, (long)r->r_offset, from_pretty_name,
fromsym_name, from_pretty_name_p,
to_pretty_name, tosec, tosym_name, to_pretty_name_p);
if (!match(tosec, mismatch->bad_tosec) &&
is_executable_section(elf, get_secindex(elf, sym)))
fprintf(stderr,
"The relocation at %s+0x%lx references\n"
"section \"%s\" which is not in the list of\n"
"authorized sections. If you're adding a new section\n"
"and/or if this reference is valid, add \"%s\" to the\n"
"list of authorized sections to jump to on fault.\n"
"This can be achieved by adding \"%s\" to \n"
"OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
fromsec, (long)r->r_offset, tosec, tosec, tosec);
}
static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
const struct sectioncheck* const mismatch,
Elf_Rela* r, Elf_Sym* sym,
const char *fromsec)
{
const char* tosec = sec_name(elf, get_secindex(elf, sym));
sec_mismatch_count++;
report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
if (match(tosec, mismatch->bad_tosec))
fatal("The relocation at %s+0x%lx references\n"
"section \"%s\" which is black-listed.\n"
"Something is seriously wrong and should be fixed.\n"
"You might get more information about where this is\n"
"coming from by using scripts/check_extable.sh %s\n",
fromsec, (long)r->r_offset, tosec, modname);
else if (!is_executable_section(elf, get_secindex(elf, sym))) {
if (is_extable_fault_address(r))
fatal("The relocation at %s+0x%lx references\n"
"section \"%s\" which is not executable, IOW\n"
"it is not possible for the kernel to fault\n"
"at that address. Something is seriously wrong\n"
"and should be fixed.\n",
fromsec, (long)r->r_offset, tosec);
else
fatal("The relocation at %s+0x%lx references\n"
"section \"%s\" which is not executable, IOW\n"
"the kernel will fault if it ever tries to\n"
"jump to it. Something is seriously wrong\n"
"and should be fixed.\n",
fromsec, (long)r->r_offset, tosec);
}
}
static void check_section_mismatch(const char *modname, struct elf_info *elf,
Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
{
const char *tosec = sec_name(elf, get_secindex(elf, sym));
const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
if (mismatch) {
if (mismatch->handler)
mismatch->handler(modname, elf, mismatch,
r, sym, fromsec);
else
default_mismatch_handler(modname, elf, mismatch,
r, sym, fromsec);
}
}
static unsigned int *reloc_location(struct elf_info *elf,
Elf_Shdr *sechdr, Elf_Rela *r)
{
return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset);
}
static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
{
unsigned int r_typ = ELF_R_TYPE(r->r_info);
unsigned int *location = reloc_location(elf, sechdr, r);
switch (r_typ) {
case R_386_32:
r->r_addend = TO_NATIVE(*location);
break;
case R_386_PC32:
r->r_addend = TO_NATIVE(*location) + 4;
/* For CONFIG_RELOCATABLE=y */
if (elf->hdr->e_type == ET_EXEC)
r->r_addend += r->r_offset;
break;
}
return 0;
}
#ifndef R_ARM_CALL
#define R_ARM_CALL 28
#endif
#ifndef R_ARM_JUMP24
#define R_ARM_JUMP24 29
#endif
#ifndef R_ARM_THM_CALL
#define R_ARM_THM_CALL 10
#endif
#ifndef R_ARM_THM_JUMP24
#define R_ARM_THM_JUMP24 30
#endif
#ifndef R_ARM_THM_JUMP19
#define R_ARM_THM_JUMP19 51
#endif
static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
{
unsigned int r_typ = ELF_R_TYPE(r->r_info);
switch (r_typ) {
case R_ARM_ABS32:
/* From ARM ABI: (S + A) | T */
r->r_addend = (int)(long)
(elf->symtab_start + ELF_R_SYM(r->r_info));
break;
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_THM_CALL:
case R_ARM_THM_JUMP24:
case R_ARM_THM_JUMP19:
/* From ARM ABI: ((S + A) | T) - P */
r->r_addend = (int)(long)(elf->hdr +
sechdr->sh_offset +
(r->r_offset - sechdr->sh_addr));
break;
default:
return 1;
}
return 0;
}
static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
{
unsigned int r_typ = ELF_R_TYPE(r->r_info);
unsigned int *location = reloc_location(elf, sechdr, r);
unsigned int inst;
if (r_typ == R_MIPS_HI16)
return 1; /* skip this */
inst = TO_NATIVE(*location);
switch (r_typ) {
case R_MIPS_LO16:
r->r_addend = inst & 0xffff;
break;
case R_MIPS_26:
r->r_addend = (inst & 0x03ffffff) << 2;
break;
case R_MIPS_32:
r->r_addend = inst;
break;
}
return 0;
}
static void section_rela(const char *modname, struct elf_info *elf,
Elf_Shdr *sechdr)
{
Elf_Sym *sym;
Elf_Rela *rela;
Elf_Rela r;
unsigned int r_sym;
const char *fromsec;
Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
Elf_Rela *stop = (void *)start + sechdr->sh_size;
fromsec = sech_name(elf, sechdr);
fromsec += strlen(".rela");
/* if from section (name) is know good then skip it */
if (match(fromsec, section_white_list))
return;
for (rela = start; rela < stop; rela++) {
r.r_offset = TO_NATIVE(rela->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
if (elf->hdr->e_machine == EM_MIPS) {
unsigned int r_typ;
r_sym = ELF64_MIPS_R_SYM(rela->r_info);
r_sym = TO_NATIVE(r_sym);
r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
r.r_info = ELF64_R_INFO(r_sym, r_typ);
} else {
r.r_info = TO_NATIVE(rela->r_info);
r_sym = ELF_R_SYM(r.r_info);
}
#else
r.r_info = TO_NATIVE(rela->r_info);
r_sym = ELF_R_SYM(r.r_info);
#endif
r.r_addend = TO_NATIVE(rela->r_addend);
sym = elf->symtab_start + r_sym;
/* Skip special sections */
if (is_shndx_special(sym->st_shndx))
continue;
if (is_second_extable_reloc(start, rela, fromsec))
find_extable_entry_size(fromsec, &r);
check_section_mismatch(modname, elf, &r, sym, fromsec);
}
}
static void section_rel(const char *modname, struct elf_info *elf,
Elf_Shdr *sechdr)
{
Elf_Sym *sym;
Elf_Rel *rel;
Elf_Rela r;
unsigned int r_sym;
const char *fromsec;
Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
Elf_Rel *stop = (void *)start + sechdr->sh_size;
fromsec = sech_name(elf, sechdr);
fromsec += strlen(".rel");
/* if from section (name) is know good then skip it */
if (match(fromsec, section_white_list))
return;
for (rel = start; rel < stop; rel++) {
r.r_offset = TO_NATIVE(rel->r_offset);
#if KERNEL_ELFCLASS == ELFCLASS64
if (elf->hdr->e_machine == EM_MIPS) {
unsigned int r_typ;
r_sym = ELF64_MIPS_R_SYM(rel->r_info);
r_sym = TO_NATIVE(r_sym);
r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
r.r_info = ELF64_R_INFO(r_sym, r_typ);
} else {
r.r_info = TO_NATIVE(rel->r_info);
r_sym = ELF_R_SYM(r.r_info);
}
#else
r.r_info = TO_NATIVE(rel->r_info);
r_sym = ELF_R_SYM(r.r_info);
#endif
r.r_addend = 0;
switch (elf->hdr->e_machine) {
case EM_386:
if (addend_386_rel(elf, sechdr, &r))
continue;
break;
case EM_ARM:
if (addend_arm_rel(elf, sechdr, &r))
continue;
break;
case EM_MIPS:
if (addend_mips_rel(elf, sechdr, &r))
continue;
break;
}
sym = elf->symtab_start + r_sym;
/* Skip special sections */
if (is_shndx_special(sym->st_shndx))
continue;
if (is_second_extable_reloc(start, rel, fromsec))
find_extable_entry_size(fromsec, &r);
check_section_mismatch(modname, elf, &r, sym, fromsec);
}
}
/**
* A module includes a number of sections that are discarded
* either when loaded or when used as built-in.
* For loaded modules all functions marked __init and all data
* marked __initdata will be discarded when the module has been initialized.
* Likewise for modules used built-in the sections marked __exit
* are discarded because __exit marked function are supposed to be called
* only when a module is unloaded which never happens for built-in modules.
* The check_sec_ref() function traverses all relocation records
* to find all references to a section that reference a section that will
* be discarded and warns about it.
**/
static void check_sec_ref(struct module *mod, const char *modname,
struct elf_info *elf)
{
int i;
Elf_Shdr *sechdrs = elf->sechdrs;
/* Walk through all sections */
for (i = 0; i < elf->num_sections; i++) {
check_section(modname, elf, &elf->sechdrs[i]);
/* We want to process only relocation sections and not .init */
if (sechdrs[i].sh_type == SHT_RELA)
section_rela(modname, elf, &elf->sechdrs[i]);
else if (sechdrs[i].sh_type == SHT_REL)
section_rel(modname, elf, &elf->sechdrs[i]);
}
}
static char *remove_dot(char *s)
{
size_t n = strcspn(s, ".");
if (n && s[n]) {
size_t m = strspn(s + n + 1, "0123456789");
if (m && (s[n + m] == '.' || s[n + m] == 0))
s[n] = 0;
}
return s;
}
static void read_symbols(const char *modname)
{
const char *symname;
char *version;
char *license;
char *namespace;
struct module *mod;
struct elf_info info = { };
Elf_Sym *sym;
if (!parse_elf(&info, modname))
return;
mod = new_module(modname);
if (is_vmlinux(modname)) {
have_vmlinux = 1;
mod->skip = 1;
}
if (!is_vmlinux(modname)) {
license = get_modinfo(&info, "license");
if (!license)
warn("missing MODULE_LICENSE() in %s\n", modname);
while (license) {
if (license_is_gpl_compatible(license))
mod->gpl_compatible = 1;
else {
mod->gpl_compatible = 0;
break;
}
license = get_next_modinfo(&info, "license", license);
}
namespace = get_modinfo(&info, "import_ns");
while (namespace) {
add_namespace(&mod->imported_namespaces, namespace);
namespace = get_next_modinfo(&info, "import_ns",
namespace);
}
}
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
symname = remove_dot(info.strtab + sym->st_name);
handle_symbol(mod, &info, sym, symname);
handle_moddevtable(mod, &info, sym, symname);
}
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
symname = remove_dot(info.strtab + sym->st_name);
/* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
if (strstarts(symname, "__kstrtabns_"))
sym_update_namespace(symname + strlen("__kstrtabns_"),
namespace_from_kstrtabns(&info,
sym));
if (strstarts(symname, "__crc_"))
handle_modversion(mod, &info, sym,
symname + strlen("__crc_"));
}
// check for static EXPORT_SYMBOL_* functions && global vars
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
unsigned char bind = ELF_ST_BIND(sym->st_info);
if (bind == STB_GLOBAL || bind == STB_WEAK) {
struct symbol *s =
find_symbol(remove_dot(info.strtab +
sym->st_name));
if (s)
s->is_static = 0;
}
}
if (!is_vmlinux(modname) || vmlinux_section_warnings)
check_sec_ref(mod, modname, &info);
if (!is_vmlinux(modname)) {
version = get_modinfo(&info, "version");
if (version || all_versions)
get_src_version(modname, mod->srcversion,
sizeof(mod->srcversion) - 1);
}
parse_elf_finish(&info);
/* Our trick to get versioning for module struct etc. - it's
* never passed as an argument to an exported function, so
* the automatic versioning doesn't pick it up, but it's really
* important anyhow */
if (modversions)
mod->unres = alloc_symbol("module_layout", 0, mod->unres);
}
static void read_symbols_from_files(const char *filename)
{
FILE *in = stdin;
char fname[PATH_MAX];
if (strcmp(filename, "-") != 0) {
in = fopen(filename, "r");
if (!in)
fatal("Can't open filenames file %s: %m", filename);
}
while (fgets(fname, PATH_MAX, in) != NULL) {
if (strends(fname, "\n"))
fname[strlen(fname)-1] = '\0';
read_symbols(fname);
}
if (in != stdin)
fclose(in);
}
#define SZ 500
/* We first write the generated file into memory using the
* following helper, then compare to the file on disk and
* only update the later if anything changed */
void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
const char *fmt, ...)
{
char tmp[SZ];
int len;
va_list ap;
va_start(ap, fmt);
len = vsnprintf(tmp, SZ, fmt, ap);
buf_write(buf, tmp, len);
va_end(ap);
}
void buf_write(struct buffer *buf, const char *s, int len)
{
if (buf->size - buf->pos < len) {
buf->size += len + SZ;
buf->p = NOFAIL(realloc(buf->p, buf->size));
}
strncpy(buf->p + buf->pos, s, len);
buf->pos += len;
}
static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
{
const char *e = is_vmlinux(m) ?"":".ko";
switch (exp) {
case export_gpl:
fatal("GPL-incompatible module %s%s "
"uses GPL-only symbol '%s'\n", m, e, s);
break;
case export_unused_gpl:
fatal("GPL-incompatible module %s%s "
"uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
break;
case export_gpl_future:
warn("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("module %s%s "
"uses symbol '%s' marked UNUSED\n", m, e, s);
break;
default:
/* ignore */
break;
}
}
static int check_exports(struct module *mod)
{
struct symbol *s, *exp;
int err = 0;
for (s = mod->unres; s; s = s->next) {
const char *basename;
exp = find_symbol(s->name);
if (!exp || exp->module == mod) {
if (have_vmlinux && !s->weak) {
modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
"\"%s\" [%s.ko] undefined!\n",
s->name, mod->name);
if (!warn_unresolved)
err = 1;
}
continue;
}
basename = strrchr(mod->name, '/');
if (basename)
basename++;
else
basename = mod->name;
if (exp->namespace &&
!module_imports_namespace(mod, exp->namespace)) {
modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
"module %s uses symbol %s from namespace %s, but does not import it.\n",
basename, exp->name, exp->namespace);
if (!allow_missing_ns_imports)
err = 1;
add_namespace(&mod->missing_namespaces, exp->namespace);
}
if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);
check_for_unused(exp->export, basename, exp->name);
}
return err;
}
static int check_modname_len(struct module *mod)
{
const char *mod_name;
mod_name = strrchr(mod->name, '/');
if (mod_name == NULL)
mod_name = mod->name;
else
mod_name++;
if (strlen(mod_name) >= MODULE_NAME_LEN) {
merror("module name is too long [%s.ko]\n", mod->name);
return 1;
}
return 0;
}
/**
* Header for the generated file
**/
static void add_header(struct buffer *b, struct module *mod)
{
buf_printf(b, "#include <linux/module.h>\n");
/*
* Include build-salt.h after module.h in order to
* inherit the definitions.
*/
buf_printf(b, "#include <linux/build-salt.h>\n");
buf_printf(b, "#include <linux/vermagic.h>\n");
buf_printf(b, "#include <linux/compiler.h>\n");
buf_printf(b, "\n");
buf_printf(b, "BUILD_SALT;\n");
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
buf_printf(b, "\n");
buf_printf(b, "__visible struct module __this_module\n");
buf_printf(b, "__section(.gnu.linkonce.this_module) = {\n");
buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
if (mod->has_init)
buf_printf(b, "\t.init = init_module,\n");
if (mod->has_cleanup)
buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
"\t.exit = cleanup_module,\n"
"#endif\n");
buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
buf_printf(b, "};\n");
}
static void add_intree_flag(struct buffer *b, int is_intree)
{
if (is_intree)
buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
}
/* Cannot check for assembler */
static void add_retpoline(struct buffer *b)
{
buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
buf_printf(b, "#endif\n");
}
static void add_staging_flag(struct buffer *b, const char *name)
{
if (strstarts(name, "drivers/staging"))
buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
}
/**
* Record CRCs for unresolved symbols
**/
static int add_versions(struct buffer *b, struct module *mod)
{
struct symbol *s, *exp;
int err = 0;
for (s = mod->unres; s; s = s->next) {
exp = find_symbol(s->name);
if (!exp || exp->module == mod)
continue;
s->module = exp->module;
s->crc_valid = exp->crc_valid;
s->crc = exp->crc;
}
if (!modversions)
return err;
buf_printf(b, "\n");
buf_printf(b, "static const struct modversion_info ____versions[]\n");
buf_printf(b, "__used __section(__versions) = {\n");
for (s = mod->unres; s; s = s->next) {
if (!s->module)
continue;
if (!s->crc_valid) {
warn("\"%s\" [%s.ko] has no CRC!\n",
s->name, mod->name);
continue;
}
if (strlen(s->name) >= MODULE_NAME_LEN) {
merror("too long symbol \"%s\" [%s.ko]\n",
s->name, mod->name);
err = 1;
break;
}
buf_printf(b, "\t{ %#8x, \"%s\" },\n",
s->crc, s->name);
}
buf_printf(b, "};\n");
return err;
}
static void add_depends(struct buffer *b, struct module *mod)
{
struct symbol *s;
int first = 1;
/* Clear ->seen flag of modules that own symbols needed by this. */
for (s = mod->unres; s; s = s->next)
if (s->module)
s->module->seen = is_vmlinux(s->module->name);
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(depends, \"");
for (s = mod->unres; s; s = s->next) {
const char *p;
if (!s->module)
continue;
if (s->module->seen)
continue;
s->module->seen = 1;
p = strrchr(s->module->name, '/');
if (p)
p++;
else
p = s->module->name;
buf_printf(b, "%s%s", first ? "" : ",", p);
first = 0;
}
buf_printf(b, "\");\n");
}
static void add_srcversion(struct buffer *b, struct module *mod)
{
if (mod->srcversion[0]) {
buf_printf(b, "\n");
buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
mod->srcversion);
}
}
static void write_buf(struct buffer *b, const char *fname)
{
FILE *file;
file = fopen(fname, "w");
if (!file) {
perror(fname);
exit(1);
}
if (fwrite(b->p, 1, b->pos, file) != b->pos) {
perror(fname);
exit(1);
}
if (fclose(file) != 0) {
perror(fname);
exit(1);
}
}
static void write_if_changed(struct buffer *b, const char *fname)
{
char *tmp;
FILE *file;
struct stat st;
file = fopen(fname, "r");
if (!file)
goto write;
if (fstat(fileno(file), &st) < 0)
goto close_write;
if (st.st_size != b->pos)
goto close_write;
tmp = NOFAIL(malloc(b->pos));
if (fread(tmp, 1, b->pos, file) != b->pos)
goto free_write;
if (memcmp(tmp, b->p, b->pos) != 0)
goto free_write;
free(tmp);
fclose(file);
return;
free_write:
free(tmp);
close_write:
fclose(file);
write:
write_buf(b, fname);
}
/* parse Module.symvers file. line format:
* 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
**/
static void read_dump(const char *fname)
{
unsigned long size, pos = 0;
void *file = grab_file(fname, &size);
char *line;
if (!file)
/* No symbol versions, silently ignore */
return;
while ((line = get_next_line(&pos, file, size))) {
char *symname, *namespace, *modname, *d, *export;
unsigned int crc;
struct module *mod;
struct symbol *s;
if (!(symname = strchr(line, '\t')))
goto fail;
*symname++ = '\0';
if (!(modname = strchr(symname, '\t')))
goto fail;
*modname++ = '\0';
if (!(export = strchr(modname, '\t')))
goto fail;
*export++ = '\0';
if (!(namespace = strchr(export, '\t')))
goto fail;
*namespace++ = '\0';
crc = strtoul(line, &d, 16);
if (*symname == '\0' || *modname == '\0' || *d != '\0')
goto fail;
mod = find_module(modname);
if (!mod) {
if (is_vmlinux(modname))
have_vmlinux = 1;
mod = new_module(modname);
mod->skip = 1;
mod->from_dump = 1;
}
s = sym_add_exported(symname, mod, export_no(export));
s->is_static = 0;
sym_set_crc(symname, crc);
sym_update_namespace(symname, namespace);
}
release_file(file, size);
return;
fail:
release_file(file, size);
fatal("parse error in symbol dump file\n");
}
/* For normal builds always dump all symbols.
* For external modules only dump symbols
* that are not read from kernel Module.symvers.
**/
static int dump_sym(struct symbol *sym)
{
if (!external_module)
return 1;
if (sym->module->from_dump)
return 0;
return 1;
}
static void write_dump(const char *fname)
{
struct buffer buf = { };
struct symbol *symbol;
const char *namespace;
int n;
for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
symbol = symbolhash[n];
while (symbol) {
if (dump_sym(symbol)) {
namespace = symbol->namespace;
buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
symbol->crc, symbol->name,
symbol->module->name,
export_str(symbol->export),
namespace ? namespace : "");
}
symbol = symbol->next;
}
}
write_buf(&buf, fname);
free(buf.p);
}
static void write_namespace_deps_files(const char *fname)
{
struct module *mod;
struct namespace_list *ns;
struct buffer ns_deps_buf = {};
for (mod = modules; mod; mod = mod->next) {
if (mod->skip || !mod->missing_namespaces)
continue;
buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
for (ns = mod->missing_namespaces; ns; ns = ns->next)
buf_printf(&ns_deps_buf, " %s", ns->namespace);
buf_printf(&ns_deps_buf, "\n");
}
write_if_changed(&ns_deps_buf, fname);
free(ns_deps_buf.p);
}
struct dump_list {
struct dump_list *next;
const char *file;
};
int main(int argc, char **argv)
{
struct module *mod;
struct buffer buf = { };
char *missing_namespace_deps = NULL;
char *dump_write = NULL, *files_source = NULL;
int opt;
int err;
int n;
struct dump_list *dump_read_start = NULL;
struct dump_list **dump_read_iter = &dump_read_start;
while ((opt = getopt(argc, argv, "ei:mnsT:o:awENd:")) != -1) {
switch (opt) {
case 'e':
external_module = 1;
break;
case 'i':
*dump_read_iter =
NOFAIL(calloc(1, sizeof(**dump_read_iter)));
(*dump_read_iter)->file = optarg;
dump_read_iter = &(*dump_read_iter)->next;
break;
case 'm':
modversions = 1;
break;
case 'n':
ignore_missing_files = 1;
break;
case 'o':
dump_write = optarg;
break;
case 'a':
all_versions = 1;
break;
case 's':
vmlinux_section_warnings = 0;
break;
case 'T':
files_source = optarg;
break;
case 'w':
warn_unresolved = 1;
break;
case 'E':
sec_mismatch_fatal = 1;
break;
case 'N':
allow_missing_ns_imports = 1;
break;
case 'd':
missing_namespace_deps = optarg;
break;
default:
exit(1);
}
}
while (dump_read_start) {
struct dump_list *tmp;
read_dump(dump_read_start->file);
tmp = dump_read_start->next;
free(dump_read_start);
dump_read_start = tmp;
}
while (optind < argc)
read_symbols(argv[optind++]);
if (files_source)
read_symbols_from_files(files_source);
/*
* When there's no vmlinux, don't print warnings about
* unresolved symbols (since there'll be too many ;)
*/
if (!have_vmlinux)
warn("Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped.\n");
err = 0;
for (mod = modules; mod; mod = mod->next) {
char fname[PATH_MAX];
if (mod->skip)
continue;
buf.pos = 0;
err |= check_modname_len(mod);
err |= check_exports(mod);
add_header(&buf, mod);
add_intree_flag(&buf, !external_module);
add_retpoline(&buf);
add_staging_flag(&buf, mod->name);
err |= add_versions(&buf, mod);
add_depends(&buf, mod);
add_moddevtable(&buf, mod);
add_srcversion(&buf, mod);
sprintf(fname, "%s.mod.c", mod->name);
write_if_changed(&buf, fname);
}
if (missing_namespace_deps)
write_namespace_deps_files(missing_namespace_deps);
if (dump_write)
write_dump(dump_write);
if (sec_mismatch_count && sec_mismatch_fatal)
fatal("Section mismatches detected.\n"
"Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
struct symbol *s;
for (s = symbolhash[n]; s; s = s->next) {
/*
* Do not check "vmlinux". This avoids the same warnings
* shown twice, and false-positives for ARCH=um.
*/
if (is_vmlinux(s->module->name) && !s->module->is_dot_o)
continue;
if (s->is_static)
warn("\"%s\" [%s] is a static %s\n",
s->name, s->module->name,
export_str(s->export));
}
}
free(buf.p);
return err;
}
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