1 files changed, 209 insertions, 0 deletions

diff --git a/kernel/exec_domain.c b/kernel/exec_domain.c
new file mode 100644
index 000000000000..867d6dbeb574
--- /dev/null
+++ b/kernel/exec_domain.c
@@ -0,0 +1,209 @@
+/*
+ * Handling of different ABIs (personalities).
+ *
+ * We group personalities into execution domains which have their
+ * own handlers for kernel entry points, signal mapping, etc...
+ *
+ * 2001-05-06   Complete rewrite,  Christoph Hellwig (hch@infradead.org)
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/module.h>
+#include <linux/personality.h>
+#include <linux/sched.h>
+#include <linux/syscalls.h>
+#include <linux/sysctl.h>
+#include <linux/types.h>
+
+
+static void default_handler(int, struct pt_regs *);
+
+static struct exec_domain *exec_domains = &default_exec_domain;
+static DEFINE_RWLOCK(exec_domains_lock);
+
+
+static u_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 = {
+        .name           = "Linux",              /* name */
+        .handler        = default_handler,      /* lcall7 causes a seg fault. */
+        .pers_low       = 0,                    /* PER_LINUX personality. */
+        .pers_high      = 0,                    /* PER_LINUX personality. */
+        .signal_map     = ident_map,            /* Identity map signals. */
+        .signal_invmap  = ident_map,            /*  - both ways. */
+};
+
+
+static void
+default_handler(int segment, struct pt_regs *regp)
+{
+        set_personality(0);
+
+        if (current_thread_info()->exec_domain->handler != default_handler)
+                current_thread_info()->exec_domain->handler(segment, regp);
+        else
+                send_sig(SIGSEGV, current, 1);
+}
+
+static struct exec_domain *
+lookup_exec_domain(u_long personality)
+{
+        struct exec_domain *    ep;
+        u_long                  pers = personality(personality);
+                
+        read_lock(&exec_domains_lock);
+        for (ep = exec_domains; ep; ep = ep->next) {
+                if (pers >= ep->pers_low && pers <= ep->pers_high)
+                        if (try_module_get(ep->module))
+                                goto out;
+        }
+
+#ifdef CONFIG_KMOD
+        read_unlock(&exec_domains_lock);
+        request_module("personality-%ld", pers);
+        read_lock(&exec_domains_lock);
+
+        for (ep = exec_domains; ep; ep = ep->next) {
+                if (pers >= ep->pers_low && pers <= ep->pers_high)
+                        if (try_module_get(ep->module))
+                                goto out;
+        }
+#endif
+
+        ep = &default_exec_domain;
+out:
+        read_unlock(&exec_domains_lock);
+        return (ep);
+}
+
+int
+register_exec_domain(struct exec_domain *ep)
+{
+        struct exec_domain      *tmp;
+        int                     err = -EBUSY;
+
+        if (ep == NULL)
+                return -EINVAL;
+
+        if (ep->next != NULL)
+                return -EBUSY;
+
+        write_lock(&exec_domains_lock);
+        for (tmp = exec_domains; tmp; tmp = tmp->next) {
+                if (tmp == ep)
+                        goto out;
+        }
+
+        ep->next = exec_domains;
+        exec_domains = ep;
+        err = 0;
+
+out:
+        write_unlock(&exec_domains_lock);
+        return (err);
+}
+
+int
+unregister_exec_domain(struct exec_domain *ep)
+{
+        struct exec_domain      **epp;
+
+        epp = &exec_domains;
+        write_lock(&exec_domains_lock);
+        for (epp = &exec_domains; *epp; epp = &(*epp)->next) {
+                if (ep == *epp)
+                        goto unregister;
+        }
+        write_unlock(&exec_domains_lock);
+        return -EINVAL;
+
+unregister:
+        *epp = ep->next;
+        ep->next = NULL;
+        write_unlock(&exec_domains_lock);
+        return 0;
+}
+
+int
+__set_personality(u_long personality)
+{
+        struct exec_domain      *ep, *oep;
+
+        ep = lookup_exec_domain(personality);
+        if (ep == current_thread_info()->exec_domain) {
+                current->personality = personality;
+                return 0;
+        }
+
+        if (atomic_read(&current->fs->count) != 1) {
+                struct fs_struct *fsp, *ofsp;
+
+                fsp = copy_fs_struct(current->fs);
+                if (fsp == NULL) {
+                        module_put(ep->module);
+                        return -ENOMEM;
+                }
+
+                task_lock(current);
+                ofsp = current->fs;
+                current->fs = fsp;
+                task_unlock(current);
+
+                put_fs_struct(ofsp);
+        }
+
+        /*
+         * At that point we are guaranteed to be the sole owner of
+         * current->fs.
+         */
+
+        current->personality = personality;
+        oep = current_thread_info()->exec_domain;
+        current_thread_info()->exec_domain = ep;
+        set_fs_altroot();
+
+        module_put(oep->module);
+        return 0;
+}
+
+int
+get_exec_domain_list(char *page)
+{
+        struct exec_domain      *ep;
+        int                     len = 0;
+
+        read_lock(&exec_domains_lock);
+        for (ep = exec_domains; ep && len < PAGE_SIZE - 80; ep = ep->next)
+                len += sprintf(page + len, "%d-%d\t%-16s\t[%s]\n",
+                               ep->pers_low, ep->pers_high, ep->name,
+                               module_name(ep->module));
+        read_unlock(&exec_domains_lock);
+        return (len);
+}
+
+asmlinkage long
+sys_personality(u_long personality)
+{
+        u_long old = current->personality;
+
+        if (personality != 0xffffffff) {
+                set_personality(personality);
+                if (current->personality != personality)
+                        return -EINVAL;
+        }
+
+        return (long)old;
+}
+
+
+EXPORT_SYMBOL(register_exec_domain);
+EXPORT_SYMBOL(unregister_exec_domain);
+EXPORT_SYMBOL(__set_personality);