hush/modutils/modprobe.c
Denys Vlasenko da879ec2e9 modprobe: protect against possible SEGV
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2010-01-26 08:17:45 +01:00

464 lines
12 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Modprobe written from scratch for BusyBox
*
* Copyright (c) 2008 Timo Teras <timo.teras@iki.fi>
* Copyright (c) 2008 Vladimir Dronnikov
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
/* Note that unlike older versions of modules.dep/depmod (busybox and m-i-t),
* we expect the full dependency list to be specified in modules.dep.
* Older versions would only export the direct dependency list.
*/
#include "libbb.h"
#include "modutils.h"
#include <sys/utsname.h>
#include <fnmatch.h>
//#define DBG(fmt, ...) bb_error_msg("%s: " fmt, __func__, ## __VA_ARGS__)
#define DBG(...) ((void)0)
#define MODULE_FLAG_LOADED 0x0001
#define MODULE_FLAG_NEED_DEPS 0x0002
/* "was seen in modules.dep": */
#define MODULE_FLAG_FOUND_IN_MODDEP 0x0004
#define MODULE_FLAG_BLACKLISTED 0x0008
struct module_entry { /* I'll call it ME. */
unsigned flags;
char *modname; /* stripped of /path/, .ext and s/-/_/g */
const char *probed_name; /* verbatim as seen on cmdline */
char *options; /* options from config files */
llist_t *realnames; /* strings. if this module is an alias, */
/* real module name is one of these. */
//Can there really be more than one? Example from real kernel?
llist_t *deps; /* strings. modules we depend on */
};
/* NB: INSMOD_OPT_SILENT bit suppresses ONLY non-existent modules,
* not deleted ones (those are still listed in modules.dep).
* module-init-tools version 3.4:
* # modprobe bogus
* FATAL: Module bogus not found. [exitcode 1]
* # modprobe -q bogus [silent, exitcode still 1]
* but:
* # rm kernel/drivers/net/dummy.ko
* # modprobe -q dummy
* FATAL: Could not open '/lib/modules/xxx/kernel/drivers/net/dummy.ko': No such file or directory
* [exitcode 1]
*/
#define MODPROBE_OPTS "acdlnrt:VC:" IF_FEATURE_MODPROBE_BLACKLIST("b")
enum {
MODPROBE_OPT_INSERT_ALL = (INSMOD_OPT_UNUSED << 0), /* a */
MODPROBE_OPT_DUMP_ONLY = (INSMOD_OPT_UNUSED << 1), /* c */
MODPROBE_OPT_D = (INSMOD_OPT_UNUSED << 2), /* d */
MODPROBE_OPT_LIST_ONLY = (INSMOD_OPT_UNUSED << 3), /* l */
MODPROBE_OPT_SHOW_ONLY = (INSMOD_OPT_UNUSED << 4), /* n */
MODPROBE_OPT_REMOVE = (INSMOD_OPT_UNUSED << 5), /* r */
MODPROBE_OPT_RESTRICT = (INSMOD_OPT_UNUSED << 6), /* t */
MODPROBE_OPT_VERONLY = (INSMOD_OPT_UNUSED << 7), /* V */
MODPROBE_OPT_CONFIGFILE = (INSMOD_OPT_UNUSED << 8), /* C */
MODPROBE_OPT_BLACKLIST = (INSMOD_OPT_UNUSED << 9) * ENABLE_FEATURE_MODPROBE_BLACKLIST,
};
struct globals {
llist_t *db; /* MEs of all modules ever seen (caching for speed) */
llist_t *probes; /* MEs of module(s) requested on cmdline */
char *cmdline_mopts; /* module options from cmdline */
int num_unresolved_deps;
/* bool. "Did we have 'symbol:FOO' requested on cmdline?" */
smallint need_symbols;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { } while (0)
static int read_config(const char *path);
static char *gather_options_str(char *opts, const char *append)
{
/* Speed-optimized. We call gather_options_str many times. */
if (append) {
if (opts == NULL) {
opts = xstrdup(append);
} else {
int optlen = strlen(opts);
opts = xrealloc(opts, optlen + strlen(append) + 2);
sprintf(opts + optlen, " %s", append);
}
}
return opts;
}
static struct module_entry *helper_get_module(const char *module, int create)
{
char modname[MODULE_NAME_LEN];
struct module_entry *e;
llist_t *l;
filename2modname(module, modname);
for (l = G.db; l != NULL; l = l->link) {
e = (struct module_entry *) l->data;
if (strcmp(e->modname, modname) == 0)
return e;
}
if (!create)
return NULL;
e = xzalloc(sizeof(*e));
e->modname = xstrdup(modname);
llist_add_to(&G.db, e);
return e;
}
static struct module_entry *get_or_add_modentry(const char *module)
{
return helper_get_module(module, 1);
}
static struct module_entry *get_modentry(const char *module)
{
return helper_get_module(module, 0);
}
static void add_probe(const char *name)
{
struct module_entry *m;
m = get_or_add_modentry(name);
if (!(option_mask32 & MODPROBE_OPT_REMOVE)
&& (m->flags & MODULE_FLAG_LOADED)
) {
DBG("skipping %s, it is already loaded", name);
return;
}
DBG("queuing %s", name);
m->probed_name = name;
m->flags |= MODULE_FLAG_NEED_DEPS;
llist_add_to_end(&G.probes, m);
G.num_unresolved_deps++;
if (ENABLE_FEATURE_MODUTILS_SYMBOLS
&& strncmp(m->modname, "symbol:", 7) == 0
) {
G.need_symbols = 1;
}
}
static int FAST_FUNC config_file_action(const char *filename,
struct stat *statbuf UNUSED_PARAM,
void *userdata UNUSED_PARAM,
int depth UNUSED_PARAM)
{
char *tokens[3];
parser_t *p;
struct module_entry *m;
int rc = TRUE;
if (bb_basename(filename)[0] == '.')
goto error;
p = config_open2(filename, fopen_for_read);
if (p == NULL) {
rc = FALSE;
goto error;
}
while (config_read(p, tokens, 3, 2, "# \t", PARSE_NORMAL)) {
//Use index_in_strings?
if (strcmp(tokens[0], "alias") == 0) {
/* alias <wildcard> <modulename> */
llist_t *l;
char wildcard[MODULE_NAME_LEN];
char *rmod;
if (tokens[2] == NULL)
continue;
filename2modname(tokens[1], wildcard);
for (l = G.probes; l != NULL; l = l->link) {
m = (struct module_entry *) l->data;
if (fnmatch(wildcard, m->modname, 0) != 0)
continue;
rmod = filename2modname(tokens[2], NULL);
llist_add_to(&m->realnames, rmod);
if (m->flags & MODULE_FLAG_NEED_DEPS) {
m->flags &= ~MODULE_FLAG_NEED_DEPS;
G.num_unresolved_deps--;
}
m = get_or_add_modentry(rmod);
if (!(m->flags & MODULE_FLAG_NEED_DEPS)) {
m->flags |= MODULE_FLAG_NEED_DEPS;
G.num_unresolved_deps++;
}
}
} else if (strcmp(tokens[0], "options") == 0) {
/* options <modulename> <option...> */
if (tokens[2] == NULL)
continue;
m = get_or_add_modentry(tokens[1]);
m->options = gather_options_str(m->options, tokens[2]);
} else if (strcmp(tokens[0], "include") == 0) {
/* include <filename> */
read_config(tokens[1]);
} else if (ENABLE_FEATURE_MODPROBE_BLACKLIST
&& strcmp(tokens[0], "blacklist") == 0
) {
/* blacklist <modulename> */
get_or_add_modentry(tokens[1])->flags |= MODULE_FLAG_BLACKLISTED;
}
}
config_close(p);
error:
return rc;
}
static int read_config(const char *path)
{
return recursive_action(path, ACTION_RECURSE | ACTION_QUIET,
config_file_action, NULL, NULL, 1);
}
static const char *humanly_readable_name(struct module_entry *m)
{
/* probed_name may be NULL. modname always exists. */
return m->probed_name ? m->probed_name : m->modname;
}
/* Return: similar to bb_init_module:
* 0 on success,
* -errno on open/read error,
* errno on init_module() error
*/
static int do_modprobe(struct module_entry *m)
{
struct module_entry *m2 = m2; /* for compiler */
char *fn, *options;
int rc, first;
llist_t *l;
if (!(m->flags & MODULE_FLAG_FOUND_IN_MODDEP)) {
if (!(option_mask32 & INSMOD_OPT_SILENT))
bb_error_msg("module %s not found in modules.dep",
humanly_readable_name(m));
return -ENOENT;
}
DBG("do_modprob'ing %s", m->modname);
if (!(option_mask32 & MODPROBE_OPT_REMOVE))
m->deps = llist_rev(m->deps);
for (l = m->deps; l != NULL; l = l->link)
DBG("dep: %s", l->data);
first = 1;
rc = 0;
while (m->deps) {
rc = 0;
fn = llist_pop(&m->deps); /* we leak it */
m2 = get_or_add_modentry(fn);
if (option_mask32 & MODPROBE_OPT_REMOVE) {
/* modprobe -r */
if (m2->flags & MODULE_FLAG_LOADED) {
rc = bb_delete_module(m2->modname, O_EXCL);
if (rc) {
if (first) {
bb_error_msg("failed to unload module %s: %s",
humanly_readable_name(m2),
moderror(rc));
break;
}
} else {
m2->flags &= ~MODULE_FLAG_LOADED;
}
}
/* do not error out if *deps* fail to unload */
first = 0;
continue;
}
if (m2->flags & MODULE_FLAG_LOADED) {
DBG("%s is already loaded, skipping", fn);
continue;
}
options = m2->options;
m2->options = NULL;
if (m == m2)
options = gather_options_str(options, G.cmdline_mopts);
rc = bb_init_module(fn, options);
DBG("loaded %s '%s', rc:%d", fn, options, rc);
if (rc == EEXIST)
rc = 0;
free(options);
if (rc) {
bb_error_msg("failed to load module %s (%s): %s",
humanly_readable_name(m2),
fn,
moderror(rc)
);
break;
}
m2->flags |= MODULE_FLAG_LOADED;
}
return rc;
}
static void load_modules_dep(void)
{
struct module_entry *m;
char *colon, *tokens[2];
parser_t *p;
/* Modprobe does not work at all without modules.dep,
* even if the full module name is given. Returning error here
* was making us later confuse user with this message:
* "module /full/path/to/existing/file/module.ko not found".
* It's better to die immediately, with good message.
* xfopen_for_read provides that. */
p = config_open2(CONFIG_DEFAULT_DEPMOD_FILE, xfopen_for_read);
while (G.num_unresolved_deps
&& config_read(p, tokens, 2, 1, "# \t", PARSE_NORMAL)
) {
colon = last_char_is(tokens[0], ':');
if (colon == NULL)
continue;
*colon = 0;
m = get_modentry(tokens[0]);
if (m == NULL)
continue;
/* Optimization... */
if ((m->flags & MODULE_FLAG_LOADED)
&& !(option_mask32 & MODPROBE_OPT_REMOVE)
) {
DBG("skip deps of %s, it's already loaded", tokens[0]);
continue;
}
m->flags |= MODULE_FLAG_FOUND_IN_MODDEP;
if ((m->flags & MODULE_FLAG_NEED_DEPS) && (m->deps == NULL)) {
G.num_unresolved_deps--;
llist_add_to(&m->deps, xstrdup(tokens[0]));
if (tokens[1])
string_to_llist(tokens[1], &m->deps, " \t");
} else
DBG("skipping dep line");
}
config_close(p);
}
int modprobe_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int modprobe_main(int argc UNUSED_PARAM, char **argv)
{
struct utsname uts;
int rc;
unsigned opt;
struct module_entry *me;
opt_complementary = "q-v:v-q";
opt = getopt32(argv, INSMOD_OPTS MODPROBE_OPTS INSMOD_ARGS, NULL, NULL);
argv += optind;
if (opt & (MODPROBE_OPT_DUMP_ONLY | MODPROBE_OPT_LIST_ONLY |
MODPROBE_OPT_SHOW_ONLY))
bb_error_msg_and_die("not supported");
if (!argv[0]) {
if (opt & MODPROBE_OPT_REMOVE) {
/* "modprobe -r" (w/o params).
* "If name is NULL, all unused modules marked
* autoclean will be removed".
*/
if (bb_delete_module(NULL, O_NONBLOCK | O_EXCL) != 0)
bb_perror_msg_and_die("rmmod");
}
return EXIT_SUCCESS;
}
/* Goto modules location */
xchdir(CONFIG_DEFAULT_MODULES_DIR);
uname(&uts);
xchdir(uts.release);
/* Retrieve module names of already loaded modules */
{
char *s;
parser_t *parser = config_open2("/proc/modules", fopen_for_read);
while (config_read(parser, &s, 1, 1, "# \t", PARSE_NORMAL & ~PARSE_GREEDY))
get_or_add_modentry(s)->flags |= MODULE_FLAG_LOADED;
config_close(parser);
}
if (opt & (MODPROBE_OPT_INSERT_ALL | MODPROBE_OPT_REMOVE)) {
/* Each argument is a module name */
do {
DBG("adding module %s", *argv);
add_probe(*argv++);
} while (*argv);
} else {
/* First argument is module name, rest are parameters */
DBG("probing just module %s", *argv);
add_probe(argv[0]);
G.cmdline_mopts = parse_cmdline_module_options(argv);
}
/* Happens if all requested modules are already loaded */
if (G.probes == NULL)
return EXIT_SUCCESS;
read_config("/etc/modprobe.conf");
read_config("/etc/modprobe.d");
if (ENABLE_FEATURE_MODUTILS_SYMBOLS && G.need_symbols)
read_config("modules.symbols");
load_modules_dep();
if (ENABLE_FEATURE_MODUTILS_ALIAS && G.num_unresolved_deps) {
read_config("modules.alias");
load_modules_dep();
}
rc = 0;
while ((me = llist_pop(&G.probes)) != NULL) {
if (me->realnames == NULL) {
DBG("probing by module name");
/* This is not an alias. Literal names are blacklisted
* only if '-b' is given.
*/
if (!(opt & MODPROBE_OPT_BLACKLIST)
|| !(me->flags & MODULE_FLAG_BLACKLISTED)
) {
rc |= do_modprobe(me);
}
continue;
}
/* Probe all real names for the alias */
do {
char *realname = llist_pop(&me->realnames);
struct module_entry *m2;
DBG("probing alias %s by realname %s", me->modname, realname);
m2 = get_or_add_modentry(realname);
if (!(m2->flags & MODULE_FLAG_BLACKLISTED)
&& (!(m2->flags & MODULE_FLAG_LOADED)
|| (opt & MODPROBE_OPT_REMOVE))
) {
//TODO: we can pass "me" as 2nd param to do_modprobe,
//and make do_modprobe emit more meaningful error messages
//with alias name included, not just module name alias resolves to.
rc |= do_modprobe(m2);
}
free(realname);
} while (me->realnames != NULL);
}
return (rc != 0);
}