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Commit e4dc1b14 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

Use list_head in binfmt handling 



Switch single-linked binfmt formats list to usual list_head's.  This leads
to one-liners in register_binfmt() and unregister_binfmt().  The downside
is one pointer more in struct linux_binfmt.  This is not a problem, since
the set of registered binfmts on typical box is very small -- (ELF +
something distro enabled for you).

Test-booted, played with executable .txt files, modprobe/rmmod binfmt_misc.

Signed-off-by: default avatarAlexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent deba0f49

arch/mips/kernel/irixelf.c

+5 −2
Original line number Diff line number Diff line
@@ -47,8 +47,11 @@ static int irix_core_dump(long signr, struct pt_regs * regs, 
                          struct file *file);



static struct linux_binfmt irix_format = {

	NULL, THIS_MODULE, load_irix_binary, load_irix_library,

	irix_core_dump, PAGE_SIZE

	.module		= THIS_MODULE,

	.load_binary	= load_irix_binary,

	.load_shlib	= load_irix_library,

	.core_dump	= irix_core_dump,

	.min_coredump	= PAGE_SIZE,

};



/* Debugging routines. */

arch/sparc64/kernel/binfmt_aout32.c

+5 −2
Original line number Diff line number Diff line
@@ -38,8 +38,11 @@ static int load_aout32_library(struct file*); 
static int aout32_core_dump(long signr, struct pt_regs * regs, struct file *file);



static struct linux_binfmt aout32_format = {

	NULL, THIS_MODULE, load_aout32_binary, load_aout32_library, aout32_core_dump,

	PAGE_SIZE

	.module		= THIS_MODULE,

	.load_binary	= load_aout32_binary,

	.load_shlib	= load_aout32_library,

	.core_dump	= aout32_core_dump,

	.min_coredump	= PAGE_SIZE,

};



static void set_brk(unsigned long start, unsigned long end)

fs/exec.c

+6 −28
Original line number Diff line number Diff line
@@ -66,27 +66,15 @@ int suid_dumpable = 0; 
EXPORT_SYMBOL(suid_dumpable);

/* The maximal length of core_pattern is also specified in sysctl.c */



static struct linux_binfmt *formats;

static LIST_HEAD(formats);

static DEFINE_RWLOCK(binfmt_lock);



int register_binfmt(struct linux_binfmt * fmt)

{

	struct linux_binfmt ** tmp = &formats;



	if (!fmt)

		return -EINVAL;

	if (fmt->next)

		return -EBUSY;

	write_lock(&binfmt_lock);

	while (*tmp) {

		if (fmt == *tmp) {

			write_unlock(&binfmt_lock);

			return -EBUSY;

		}

		tmp = &(*tmp)->next;

	}

	fmt->next = formats;

	formats = fmt;

	list_add(&fmt->lh, &formats);

	write_unlock(&binfmt_lock);

	return 0;	

}
@@ -95,21 +83,11 @@ EXPORT_SYMBOL(register_binfmt); 


int unregister_binfmt(struct linux_binfmt * fmt)

{

	struct linux_binfmt ** tmp = &formats;



	write_lock(&binfmt_lock);

	while (*tmp) {

		if (fmt == *tmp) {

			*tmp = fmt->next;

			fmt->next = NULL;

	list_del(&fmt->lh);

	write_unlock(&binfmt_lock);

	return 0;

}

		tmp = &(*tmp)->next;

	}

	write_unlock(&binfmt_lock);

	return -EINVAL;

}



EXPORT_SYMBOL(unregister_binfmt);
@@ -155,7 +133,7 @@ asmlinkage long sys_uselib(const char __user * library) 
		struct linux_binfmt * fmt;



		read_lock(&binfmt_lock);

		for (fmt = formats ; fmt ; fmt = fmt->next) {

		list_for_each_entry(fmt, &formats, lh) {

			if (!fmt->load_shlib)

				continue;

			if (!try_module_get(fmt->module))
@@ -1284,7 +1262,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) 
	retval = -ENOENT;

	for (try=0; try<2; try++) {

		read_lock(&binfmt_lock);

		for (fmt = formats ; fmt ; fmt = fmt->next) {

		list_for_each_entry(fmt, &formats, lh) {

			int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;

			if (!fn)

				continue;

include/linux/binfmts.h

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ struct linux_binprm{ 
 * linux accepts.

 */

struct linux_binfmt {

	struct linux_binfmt * next;

	struct list_head lh;

	struct module *module;

	int (*load_binary)(struct linux_binprm *, struct  pt_regs * regs);

	int (*load_shlib)(struct file *);