1 files changed, 336 insertions, 0 deletions
diff --git a/sys/compat/linux/linux_emul.c b/sys/compat/linux/linux_emul.c
new file mode 100644
index 000000000000..dc81553c60a9
--- /dev/null
+++ b/sys/compat/linux/linux_emul.c
@@ -0,0 +1,336 @@
+/*-
+ * 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/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->used_requeue = 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;
+	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);
+	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 (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) {
+			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(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(void *arg __unused, struct proc *p)
+{
+	struct linux_emuldata *em;
+	int error = 0;
+	int *child_set_tid;
+
+	if (__predict_true(p->p_sysent != &elf_linux_sysvec))
+		return;
+
+	/* 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;
+}