linux/kernel/exec_domain.c at master · notech/linux · GitHub

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* 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/init.h>

#include <linux/kernel.h>

#include <linux/kmod.h>

#include <linux/module.h>

#include <linux/personality.h>

#include <linux/proc_fs.h>

#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/syscalls.h>

#include <linux/sysctl.h>

#include <linux/types.h>

#include <linux/fs_struct.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 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 = {

.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(unsigned int personality)

{

unsigned int pers = personality(personality);

struct exec_domain *ep;

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_MODULES

read_unlock(&exec_domains_lock);

request_module("personality-%d", 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(unsigned int personality)

{

struct exec_domain *oep = current_thread_info()->exec_domain;

current_thread_info()->exec_domain = lookup_exec_domain(personality);

current->personality = personality;

module_put(oep->module);

return 0;

}

#ifdef CONFIG_PROC_FS

static int execdomains_proc_show(struct seq_file *m, void *v)

{

struct exec_domain *ep;

read_lock(&exec_domains_lock);

for (ep = exec_domains; ep; ep = ep->next)

seq_printf(m, "%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 0;

}

static int execdomains_proc_open(struct inode *inode, struct file *file)

{

return single_open(file, execdomains_proc_show, NULL);

}

static const struct file_operations execdomains_proc_fops = {

.open = execdomains_proc_open,

.read = seq_read,

.llseek = seq_lseek,

.release = single_release,

};

static int __init proc_execdomains_init(void)

{

proc_create("execdomains", 0, NULL, &execdomains_proc_fops);

return 0;

}

module_init(proc_execdomains_init);

#endif

SYSCALL_DEFINE1(personality, unsigned int, personality)

{

unsigned int old = current->personality;

if (personality != 0xffffffff)

set_personality(personality);

return old;

}

EXPORT_SYMBOL(register_exec_domain);

EXPORT_SYMBOL(unregister_exec_domain);

EXPORT_SYMBOL(__set_personality);

linux/kernel/exec_domain.c at master · notech/linux · GitHub

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