freebsd-dev/sys/compat/linux/linux_emul.c
Kip Macy 8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00

373 lines
9.7 KiB
C

/*-
* 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/kernel.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/sysent.h>
#include <sys/sysproto.h>
#include <sys/unistd.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
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_futex.h>
struct sx emul_shared_lock;
struct mtx 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_DOLOCK)
EMUL_LOCK(&emul_lock);
em = p->p_emuldata;
if (em == NULL && locked == EMUL_DOLOCK)
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 */
em = malloc(sizeof *em, M_LINUX, M_WAITOK | M_ZERO);
em->pid = child;
em->pdeath_signal = 0;
em->flags = 0;
em->robust_futexes = NULL;
if (flags & LINUX_CLONE_THREAD) {
/* handled later in the code */
} else {
struct linux_emuldata_shared *s;
s = malloc(sizeof *s, M_LINUX, M_WAITOK | M_ZERO);
s->refs = 1;
s->group_pid = child;
LIST_INIT(&s->threads);
em->shared = s;
}
} else {
/* lookup the old one */
em = em_find(td->td_proc, EMUL_DOLOCK);
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 & LINUX_CLONE_THREAD) {
/* lookup the parent */
/*
* we dont have to lock the p_em because
* its waiting for us in linux_clone so
* there is no chance of it changing the
* p_em->shared address
*/
p_em = em_find(td->td_proc, EMUL_DONTLOCK);
KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for CLONE_THREAD\n"));
em->shared = p_em->shared;
EMUL_SHARED_WLOCK(&emul_shared_lock);
em->shared->refs++;
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
} 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);
KASSERT(p != NULL, ("process not found in proc_init\n"));
p->p_emuldata = em;
PROC_UNLOCK(p);
} else
EMUL_UNLOCK(&emul_lock);
return (0);
}
void
linux_proc_exit(void *arg __unused, struct proc *p)
{
struct linux_emuldata *em;
int error, shared_flags, shared_xstat;
struct thread *td = FIRST_THREAD_IN_PROC(p);
int *child_clear_tid;
struct proc *q, *nq;
if (__predict_true(p->p_sysent != &elf_linux_sysvec))
return;
release_futexes(p);
/* find the emuldata */
em = em_find(p, EMUL_DOLOCK);
KASSERT(em != NULL, ("proc_exit: emuldata not found.\n"));
/* reparent all procs that are not a thread leader to initproc */
if (em->shared->group_pid != p->p_pid) {
child_clear_tid = em->child_clear_tid;
EMUL_UNLOCK(&emul_lock);
sx_xlock(&proctree_lock);
wakeup(initproc);
PROC_LOCK(p);
proc_reparent(p, initproc);
p->p_sigparent = SIGCHLD;
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
} else {
child_clear_tid = em->child_clear_tid;
EMUL_UNLOCK(&emul_lock);
}
EMUL_SHARED_WLOCK(&emul_shared_lock);
shared_flags = em->shared->flags;
shared_xstat = em->shared->xstat;
LIST_REMOVE(em, threads);
em->shared->refs--;
if (em->shared->refs == 0) {
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
free(em->shared, M_LINUX);
} else
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
if ((shared_flags & EMUL_SHARED_HASXSTAT) != 0)
p->p_xstat = shared_xstat;
if (child_clear_tid != NULL) {
struct linux_sys_futex_args cup;
int null = 0;
error = copyout(&null, child_clear_tid, sizeof(null));
if (error) {
free(em, M_LINUX);
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 means there is a user space bug
*/
if (error)
printf(LMSG("futex stuff in proc_exit failed.\n"));
}
/* clean the stuff up */
free(em, M_LINUX);
/* this is a little weird but rewritten from exit1() */
sx_xlock(&proctree_lock);
q = LIST_FIRST(&p->p_children);
for (; q != NULL; q = nq) {
nq = LIST_NEXT(q, p_sibling);
if (q->p_flag & P_WEXIT)
continue;
if (__predict_false(q->p_sysent != &elf_linux_sysvec))
continue;
em = em_find(q, EMUL_DOLOCK);
KASSERT(em != NULL, ("linux_reparent: emuldata not found: %i\n", q->p_pid));
PROC_LOCK(q);
if ((q->p_flag & P_WEXIT) == 0 && em->pdeath_signal != 0) {
kern_psignal(q, em->pdeath_signal);
}
PROC_UNLOCK(q);
EMUL_UNLOCK(&emul_lock);
}
sx_xunlock(&proctree_lock);
}
/*
* 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((p->p_sysent->sv_flags & SV_ABI_MASK) ==
SV_ABI_LINUX))
/* Kill threads regardless of imgp->sysent value */
linux_kill_threads(FIRST_THREAD_IN_PROC(p), SIGKILL);
if (__predict_false(imgp->sysent != &elf_linux_sysvec
&& p->p_sysent == &elf_linux_sysvec)) {
struct linux_emuldata *em;
/*
* XXX:There's a race because here we assign p->p_emuldata NULL
* but the process is still counted as linux one for a short
* time so some other process might reference it and try to
* access its p->p_emuldata and panicing on a NULL reference.
*/
em = em_find(p, EMUL_DONTLOCK);
KASSERT(em != NULL, ("proc_exec: emuldata not found.\n"));
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) {
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
free(em->shared, M_LINUX);
} else
EMUL_SHARED_WUNLOCK(&emul_shared_lock);
free(em, M_LINUX);
}
}
void
linux_schedtail(struct thread *td)
{
struct linux_emuldata *em;
struct proc *p;
int error = 0;
int *child_set_tid;
p = td->td_proc;
/* find the emuldata */
em = em_find(p, EMUL_DOLOCK);
KASSERT(em != NULL, ("linux_schedtail: emuldata not found.\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_DOLOCK);
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;
}
void
linux_kill_threads(struct thread *td, int sig)
{
struct linux_emuldata *em, *td_em, *tmp_em;
struct proc *sp;
td_em = em_find(td->td_proc, EMUL_DONTLOCK);
KASSERT(td_em != NULL, ("linux_kill_threads: emuldata not found.\n"));
EMUL_SHARED_RLOCK(&emul_shared_lock);
LIST_FOREACH_SAFE(em, &td_em->shared->threads, threads, tmp_em) {
if (em->pid == td_em->pid)
continue;
sp = pfind(em->pid);
if ((sp->p_flag & P_WEXIT) == 0)
kern_psignal(sp, sig);
PROC_UNLOCK(sp);
#ifdef DEBUG
printf(LMSG("linux_kill_threads: kill PID %d\n"), em->pid);
#endif
}
EMUL_SHARED_RUNLOCK(&emul_shared_lock);
}