/*-
* Copyright (c) 2006 Roman Divacky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/imgact.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/proc.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/unistd.h>
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_futex.h>
#ifdef COMPAT_LINUX32
#include <machine/../linux32/linux.h>
#include <machine/../linux32/linux32_proto.h>
#else
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#endif
struct sx emul_shared_lock;
struct sx emul_lock;
/* this returns locked reference to the emuldata entry (if found) */
struct linux_emuldata *
em_find(struct proc *p, int locked)
{
struct linux_emuldata *em;
if (locked == EMUL_UNLOCKED)
EMUL_LOCK(&emul_lock);
em = p->p_emuldata;
if (em == NULL && locked == EMUL_UNLOCKED)
EMUL_UNLOCK(&emul_lock);
return (em);
}
int
linux_proc_init(struct thread *td, pid_t child, int flags)
{
struct linux_emuldata *em, *p_em;
struct proc *p;
if (child != 0) {
/* non-exec call */
MALLOC(em, struct linux_emuldata *, sizeof *em, M_LINUX, M_WAITOK | M_ZERO);
em->pid = child;
if (flags & CLONE_VM) {
/* handled later in the code */
} else {
struct linux_emuldata_shared *s;
MALLOC(s, struct linux_emuldata_shared *, sizeof *s, M_LINUX, M_WAITOK | M_ZERO);
em->shared = s;
s->refs = 1;
s->group_pid = child;
LIST_INIT(&s->threads);
}
p = pfind(child);
if (p == NULL)
panic("process not found in proc_init\n");
p->p_emuldata = em;
PROC_UNLOCK(p);
} else {
/* lookup the old one */
em = em_find(td->td_proc, EMUL_UNLOCKED);
KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
}
em->child_clear_tid = NULL;
em->child_set_tid = NULL;
/* allocate the shared struct only in clone()/fork cases
* in the case of clone() td = calling proc and child = pid of
* the newly created proc
*/
if (child != 0) {
if (flags & CLONE_VM) {
/* lookup the parent */
p_em = em_find(td->td_proc, EMUL_LOCKED);
KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for CLONE_VM\n"));
em->shared = p_em->shared;
em->shared->refs++;
} else {
/* handled earlier to avoid malloc(M_WAITOK) with rwlock held */
}
}
if (child != 0) {
EMUL_SHARED_WLOCK(&emul_shared_lock);
LIST_INSERT_HEAD(&em->shared->threads, em, threads);
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
p = pfind(child);
PROC_UNLOCK(p);
/* we might have a sleeping linux_schedtail */
wakeup(&p->p_emuldata);
} else
EMUL_UNLOCK(&emul_lock);
return (0);
}
void
linux_proc_exit(void *arg __unused, struct proc *p)
{
struct linux_emuldata *em;
int error;
struct thread *td = FIRST_THREAD_IN_PROC(p);
int *child_clear_tid;
if (__predict_true(p->p_sysent != &elf_linux_sysvec))
return;
/* find the emuldata */
em = em_find(p, EMUL_UNLOCKED);
KASSERT(em != NULL, ("proc_exit: emuldata not found.\n"));
child_clear_tid = em->child_clear_tid;
EMUL_UNLOCK(&emul_lock);
EMUL_SHARED_WLOCK(&emul_shared_lock);
LIST_REMOVE(em, threads);
PROC_LOCK(p);
p->p_emuldata = NULL;
PROC_UNLOCK(p);
em->shared->refs--;
if (em->shared->refs == 0)
FREE(em->shared, M_LINUX);
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
if (child_clear_tid != NULL) {
struct linux_sys_futex_args cup;
int null = 0;
error = copyout(&null, child_clear_tid, sizeof(null));
if (error)
return;
/* futexes stuff */
cup.uaddr = child_clear_tid;
cup.op = LINUX_FUTEX_WAKE;
cup.val = 0x7fffffff; /* Awake everyone */
cup.timeout = NULL;
cup.uaddr2 = NULL;
cup.val3 = 0;
error = linux_sys_futex(FIRST_THREAD_IN_PROC(p), &cup);
/* this cannot happen at the moment and if this happens
* it probably mean there is a userspace bug
*/
if (error)
printf(LMSG("futex stuff in proc_exit failed.\n"));
}
/* clean the stuff up */
FREE(em, M_LINUX);
}
/* This is used in a case of transition from FreeBSD binary execing to linux binary
* in this case we create linux emuldata proc entry with the pid of the currently running
* process.
*/
void linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
{
if (__predict_false(imgp->sysent == &elf_linux_sysvec
&& p->p_sysent != &elf_linux_sysvec))
linux_proc_init(FIRST_THREAD_IN_PROC(p), p->p_pid, 0);
if (__predict_false(imgp->sysent != &elf_linux_sysvec
&& p->p_sysent == &elf_linux_sysvec)) {
struct linux_emuldata *em;
em = em_find(p, EMUL_UNLOCKED);
KASSERT(em != NULL, ("proc_exec: emuldata not found.\n"));
EMUL_UNLOCK(&emul_lock);
EMUL_SHARED_WLOCK(&emul_shared_lock);
LIST_REMOVE(em, threads);
PROC_LOCK(p);
p->p_emuldata = NULL;
PROC_UNLOCK(p);
em->shared->refs--;
if (em->shared->refs == 0)
FREE(em->shared, M_LINUX);
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
FREE(em, M_LINUX);
}
}
extern int hz; /* in subr_param.c */
void
linux_schedtail(void *arg __unused, struct proc *p)
{
struct linux_emuldata *em;
int error = 0;
#ifdef DEBUG
struct thread *td = FIRST_THREAD_IN_PROC(p);
#endif
int *child_set_tid;
if (p->p_sysent != &elf_linux_sysvec)
return;
retry:
/* find the emuldata */
em = em_find(p, EMUL_UNLOCKED);
if (em == NULL) {
/* We might have been called before proc_init for this process so
* tsleep and be woken up by it. We use p->p_emuldata for this
*/
error = tsleep(&p->p_emuldata, PLOCK, "linux_schedtail", hz);
if (error == 0)
goto retry;
panic("no emuldata found for userreting process.\n");
}
child_set_tid = em->child_set_tid;
EMUL_UNLOCK(&emul_lock);
if (child_set_tid != NULL)
error = copyout(&p->p_pid, (int *) child_set_tid, sizeof(p->p_pid));
return;
}
int
linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
{
struct linux_emuldata *em;
#ifdef DEBUG
if (ldebug(set_tid_address))
printf(ARGS(set_tid_address, "%p"), args->tidptr);
#endif
/* find the emuldata */
em = em_find(td->td_proc, EMUL_UNLOCKED);
KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
em->child_clear_tid = args->tidptr;
td->td_retval[0] = td->td_proc->p_pid;
EMUL_UNLOCK(&emul_lock);
return 0;
}
