Import changeset

1 files changed, 163 insertions, 0 deletions

diff --git a/kernel/exec_domain.c b/kernel/exec_domain.c
new file mode 100644
index 000000000000..1daf64cc19b6
--- /dev/null
+++ b/kernel/exec_domain.c
@@ -0,0 +1,163 @@
+#include <linux/mm.h>
+#include <linux/smp_lock.h>
+#include <linux/module.h>
+
+static asmlinkage void no_lcall7(int segment, struct pt_regs * regs);
+
+
+static unsigned long ident_map[32] = {
+	0,	1,	2,	3,	4,	5,	6,	7,
+	8,	9,	10,	11,	12,	13,	14,	15,
+	16,	17,	18,	19,	20,	21,	22,	23,
+	24,	25,	26,	27,	28,	29,	30,	31
+};
+
+struct exec_domain default_exec_domain = {
+	"Linux",	/* name */
+	no_lcall7,	/* lcall7 causes a seg fault. */
+	0, 0xff,	/* All personalities. */
+	ident_map,	/* Identity map signals. */
+	ident_map,	/*  - both ways. */
+	NULL,		/* No usage counter. */
+	NULL		/* Nothing after this in the list. */
+};
+
+static struct exec_domain *exec_domains = &default_exec_domain;
+static rwlock_t exec_domains_lock = RW_LOCK_UNLOCKED;
+
+static asmlinkage void no_lcall7(int segment, struct pt_regs * regs)
+{
+  /*
+   * This may have been a static linked SVr4 binary, so we would have the
+   * personality set incorrectly.  Check to see whether SVr4 is available,
+   * and use it, otherwise give the user a SEGV.
+   */
+	set_personality(PER_SVR4);
+
+	if (current->exec_domain && current->exec_domain->handler
+	&& current->exec_domain->handler != no_lcall7) {
+		current->exec_domain->handler(segment, regs);
+		return;
+	}
+
+	send_sig(SIGSEGV, current, 1);
+}
+
+static struct exec_domain *lookup_exec_domain(unsigned long personality)
+{
+	unsigned long pers = personality & PER_MASK;
+	struct exec_domain *it;
+
+	read_lock(&exec_domains_lock);
+	for (it=exec_domains; it; it=it->next)
+		if (pers >= it->pers_low && pers <= it->pers_high) {
+			if (!try_inc_mod_count(it->module))
+				continue;
+			read_unlock(&exec_domains_lock);
+			return it;
+		}
+	read_unlock(&exec_domains_lock);
+
+	/* Should never get this far. */
+	printk(KERN_ERR "No execution domain for personality 0x%02lx\n", pers);
+	return NULL;
+}
+
+int register_exec_domain(struct exec_domain *it)
+{
+	struct exec_domain *tmp;
+
+	if (!it)
+		return -EINVAL;
+	if (it->next)
+		return -EBUSY;
+	write_lock(&exec_domains_lock);
+	for (tmp=exec_domains; tmp; tmp=tmp->next)
+		if (tmp == it) {
+			write_unlock(&exec_domains_lock);
+			return -EBUSY;
+		}
+	it->next = exec_domains;
+	exec_domains = it;
+	write_unlock(&exec_domains_lock);
+	return 0;
+}
+
+int unregister_exec_domain(struct exec_domain *it)
+{
+	struct exec_domain ** tmp;
+
+	tmp = &exec_domains;
+	write_lock(&exec_domains_lock);
+	while (*tmp) {
+		if (it == *tmp) {
+			*tmp = it->next;
+			it->next = NULL;
+			write_unlock(&exec_domains_lock);
+			return 0;
+		}
+		tmp = &(*tmp)->next;
+	}
+	write_unlock(&exec_domains_lock);
+	return -EINVAL;
+}
+
+void __set_personality(unsigned long personality)
+{
+	struct exec_domain *it, *prev;
+
+	it = lookup_exec_domain(personality);
+	if (it == current->exec_domain) {
+		current->personality = personality;
+		return;
+	}
+	if (!it)
+		return;
+	if (atomic_read(&current->fs->count) != 1) {
+		struct fs_struct *new = copy_fs_struct(current->fs);
+		struct fs_struct *old;
+		if (!new) {
+			put_exec_domain(it);
+			return;
+		}
+		task_lock(current);
+		old = current->fs;
+		current->fs = new;
+		task_unlock(current);
+		put_fs_struct(old);
+	}
+	/*
+	 * At that point we are guaranteed to be the sole owner of
+	 * current->fs.
+	 */
+	current->personality = personality;
+	prev = current->exec_domain;
+	current->exec_domain = it;
+	set_fs_altroot();
+	put_exec_domain(prev);
+}
+
+asmlinkage long sys_personality(unsigned long personality)
+{
+	int ret = current->personality;
+	if (personality != 0xffffffff) {
+		set_personality(personality);
+		if (current->personality != personality)
+			ret = -EINVAL;
+	}
+	return ret;
+}
+
+int get_exec_domain_list(char * page)
+{
+	int len = 0;
+	struct exec_domain * e;
+
+	read_lock(&exec_domains_lock);
+	for (e=exec_domains; e && len < PAGE_SIZE - 80; e=e->next)
+		len += sprintf(page+len, "%d-%d\t%-16s\t[%s]\n",
+			e->pers_low, e->pers_high, e->name,
+			e->module ? e->module->name : "kernel");
+	read_unlock(&exec_domains_lock);
+	return len;
+}