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module: generic each_symbol iterator function
Introduce an each_symbol() iterator to avoid duplicating the knowledge about the 5 different sections containing symbols. Currently only used by find_symbol(), but will be used by symbol_put_addr() too. (Includes NULL ptr deref fix by Jiri Kosina <jkosina@suse.cz>) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Rusty Russell
parent
da39ba5e1d
commit
dafd0940c9
254
kernel/module.c
254
kernel/module.c
@ -152,28 +152,127 @@ extern const unsigned long __start___kcrctab_unused_gpl[];
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#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
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#endif
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/* lookup symbol in given range of kernel_symbols */
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static const struct kernel_symbol *lookup_symbol(const char *name,
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const struct kernel_symbol *start,
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const struct kernel_symbol *stop)
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struct symsearch {
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const struct kernel_symbol *start, *stop;
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const unsigned long *crcs;
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enum {
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NOT_GPL_ONLY,
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GPL_ONLY,
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WILL_BE_GPL_ONLY,
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} licence;
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bool unused;
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};
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static bool each_symbol_in_section(const struct symsearch *arr,
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unsigned int arrsize,
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struct module *owner,
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bool (*fn)(const struct symsearch *syms,
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struct module *owner,
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unsigned int symnum, void *data),
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void *data)
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{
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const struct kernel_symbol *ks = start;
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for (; ks < stop; ks++)
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if (strcmp(ks->name, name) == 0)
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return ks;
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return NULL;
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unsigned int i, j;
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for (j = 0; j < arrsize; j++) {
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for (i = 0; i < arr[j].stop - arr[j].start; i++)
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if (fn(&arr[j], owner, i, data))
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return true;
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}
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return false;
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}
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static bool always_ok(bool gplok, bool warn, const char *name)
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/* Returns true as soon as fn returns true, otherwise false. */
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static bool each_symbol(bool (*fn)(const struct symsearch *arr,
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struct module *owner,
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unsigned int symnum, void *data),
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void *data)
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{
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return true;
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struct module *mod;
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const struct symsearch arr[] = {
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{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
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NOT_GPL_ONLY, false },
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{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
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__start___kcrctab_gpl,
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GPL_ONLY, false },
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{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
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__start___kcrctab_gpl_future,
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WILL_BE_GPL_ONLY, false },
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{ __start___ksymtab_unused, __stop___ksymtab_unused,
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__start___kcrctab_unused,
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NOT_GPL_ONLY, true },
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{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
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__start___kcrctab_unused_gpl,
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GPL_ONLY, true },
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};
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if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
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return true;
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list_for_each_entry(mod, &modules, list) {
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struct symsearch arr[] = {
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{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
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NOT_GPL_ONLY, false },
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{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
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mod->gpl_crcs,
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GPL_ONLY, false },
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{ mod->gpl_future_syms,
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mod->gpl_future_syms + mod->num_gpl_future_syms,
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mod->gpl_future_crcs,
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WILL_BE_GPL_ONLY, false },
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{ mod->unused_syms,
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mod->unused_syms + mod->num_unused_syms,
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mod->unused_crcs,
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NOT_GPL_ONLY, true },
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{ mod->unused_gpl_syms,
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mod->unused_gpl_syms + mod->num_unused_gpl_syms,
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mod->unused_gpl_crcs,
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GPL_ONLY, true },
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};
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if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
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return true;
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}
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return false;
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}
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static bool printk_unused_warning(bool gplok, bool warn, const char *name)
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struct find_symbol_arg {
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/* Input */
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const char *name;
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bool gplok;
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bool warn;
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/* Output */
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struct module *owner;
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const unsigned long *crc;
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unsigned long value;
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};
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static bool find_symbol_in_section(const struct symsearch *syms,
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struct module *owner,
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unsigned int symnum, void *data)
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{
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if (warn) {
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struct find_symbol_arg *fsa = data;
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if (strcmp(syms->start[symnum].name, fsa->name) != 0)
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return false;
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if (!fsa->gplok) {
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if (syms->licence == GPL_ONLY)
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return false;
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if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
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printk(KERN_WARNING "Symbol %s is being used "
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"by a non-GPL module, which will not "
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"be allowed in the future\n", fsa->name);
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printk(KERN_WARNING "Please see the file "
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"Documentation/feature-removal-schedule.txt "
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"in the kernel source tree for more details.\n");
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}
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}
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if (syms->unused && fsa->warn) {
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printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
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"however this module is using it.\n", name);
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"however this module is using it.\n", fsa->name);
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printk(KERN_WARNING
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"This symbol will go away in the future.\n");
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printk(KERN_WARNING
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@ -182,64 +281,13 @@ static bool printk_unused_warning(bool gplok, bool warn, const char *name)
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"mailinglist together with submitting your code for "
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"inclusion.\n");
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}
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fsa->owner = owner;
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fsa->crc = symversion(syms->crcs, symnum);
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fsa->value = syms->start[symnum].value;
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return true;
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}
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static bool gpl_only_unused_warning(bool gplok, bool warn, const char *name)
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{
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if (!gplok)
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return false;
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return printk_unused_warning(gplok, warn, name);
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}
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static bool gpl_only(bool gplok, bool warn, const char *name)
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{
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return gplok;
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}
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static bool warn_if_not_gpl(bool gplok, bool warn, const char *name)
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{
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if (!gplok && warn) {
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printk(KERN_WARNING "Symbol %s is being used "
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"by a non-GPL module, which will not "
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"be allowed in the future\n", name);
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printk(KERN_WARNING "Please see the file "
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"Documentation/feature-removal-schedule.txt "
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"in the kernel source tree for more details.\n");
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}
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return true;
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}
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struct symsearch {
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const struct kernel_symbol *start, *stop;
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const unsigned long *crcs;
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bool (*check)(bool gplok, bool warn, const char *name);
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};
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/* Look through this array of symbol tables for a symbol match which
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* passes the check function. */
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static const struct kernel_symbol *search_symarrays(const struct symsearch *arr,
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unsigned int num,
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const char *name,
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bool gplok,
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bool warn,
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const unsigned long **crc)
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{
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unsigned int i;
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const struct kernel_symbol *ks;
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for (i = 0; i < num; i++) {
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ks = lookup_symbol(name, arr[i].start, arr[i].stop);
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if (!ks || !arr[i].check(gplok, warn, name))
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continue;
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if (crc)
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*crc = symversion(arr[i].crcs, ks - arr[i].start);
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return ks;
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}
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return NULL;
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}
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/* Find a symbol, return value, (optional) crc and (optional) module
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* which owns it */
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static unsigned long find_symbol(const char *name,
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@ -248,60 +296,36 @@ static unsigned long find_symbol(const char *name,
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bool gplok,
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bool warn)
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{
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struct module *mod;
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const struct kernel_symbol *ks;
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const struct symsearch arr[] = {
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{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
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always_ok },
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{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
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__start___kcrctab_gpl, gpl_only },
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{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
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__start___kcrctab_gpl_future, warn_if_not_gpl },
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{ __start___ksymtab_unused, __stop___ksymtab_unused,
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__start___kcrctab_unused, printk_unused_warning },
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{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
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__start___kcrctab_unused_gpl, gpl_only_unused_warning },
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};
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struct find_symbol_arg fsa;
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/* Core kernel first. */
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ks = search_symarrays(arr, ARRAY_SIZE(arr), name, gplok, warn, crc);
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if (ks) {
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fsa.name = name;
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fsa.gplok = gplok;
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fsa.warn = warn;
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if (each_symbol(find_symbol_in_section, &fsa)) {
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if (owner)
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*owner = NULL;
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return ks->value;
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}
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/* Now try modules. */
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list_for_each_entry(mod, &modules, list) {
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struct symsearch arr[] = {
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{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
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always_ok },
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{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
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mod->gpl_crcs, gpl_only },
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{ mod->gpl_future_syms,
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mod->gpl_future_syms + mod->num_gpl_future_syms,
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mod->gpl_future_crcs, warn_if_not_gpl },
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{ mod->unused_syms,
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mod->unused_syms + mod->num_unused_syms,
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mod->unused_crcs, printk_unused_warning },
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{ mod->unused_gpl_syms,
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mod->unused_gpl_syms + mod->num_unused_gpl_syms,
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mod->unused_gpl_crcs, gpl_only_unused_warning },
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};
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ks = search_symarrays(arr, ARRAY_SIZE(arr),
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name, gplok, warn, crc);
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if (ks) {
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if (owner)
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*owner = mod;
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return ks->value;
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}
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*owner = fsa.owner;
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if (crc)
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*crc = fsa.crc;
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return fsa.value;
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}
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DEBUGP("Failed to find symbol %s\n", name);
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return -ENOENT;
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}
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/* lookup symbol in given range of kernel_symbols */
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static const struct kernel_symbol *lookup_symbol(const char *name,
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const struct kernel_symbol *start,
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const struct kernel_symbol *stop)
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{
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const struct kernel_symbol *ks = start;
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for (; ks < stop; ks++)
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if (strcmp(ks->name, name) == 0)
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return ks;
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return NULL;
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}
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/* Search for module by name: must hold module_mutex. */
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static struct module *find_module(const char *name)
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{
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