Submitted by: Juergen Lock <nox@jelal.hb.north.de>

Obtained from: other people on the net ?

1. stepping over syscalls (gdb ni) sends you to DDB, and returned
to the wrong address afterwards, with or without DDB.  patch in
i386/i386/trap.c below.

2. the linux emulator (modload'ed) still causes panics with DIAGNOSTIC,
re-applied a patch posted to one of the lists...

5 files changed, 155 insertions, 31 deletions

diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index 37d8e2e..ec1e937 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)trap.c	7.4 (Berkeley) 5/13/91
- *	$Id: trap.c,v 1.58 1995/07/30 17:49:24 davidg Exp $
+ *	$Id: trap.c,v 1.59 1995/08/21 18:06:48 davidg Exp $
  */
 
 /*
@@ -78,6 +78,11 @@
 int	trap_pfault	__P((struct trapframe *, int));
 void	trap_fatal	__P((struct trapframe *));
 
+extern inthand_t IDTVEC(syscall);
+#ifdef COMPAT_LINUX
+extern inthand_t IDTVEC(linux_syscall);
+#endif
+
 #define MAX_TRAP_MSG		27
 char *trap_msg[] = {
 	"",					/*  0 unused */
@@ -351,14 +356,23 @@ trap(frame)
 
 #ifdef DDB
 		case T_BPTFLT:
+#ifndef DDB_NO_LCALLS
 		case T_TRCTRAP:
+#endif
 			if (kdb_trap (type, 0, &frame))
 				return;
 			break;
-#else
+#endif
+#if !defined (DDB) || defined (DDB_NO_LCALLS)
 		case T_TRCTRAP:	 /* trace trap -- someone single stepping lcall's */
 			/* Q: how do we turn it on again? */
-			frame.tf_eflags &= ~PSL_T;
+#ifdef COMPAT_LINUX
+			if (frame.tf_eip != (int) IDTVEC(syscall) &&
+			    frame.tf_eip != (int) IDTVEC(linux_syscall))
+#else
+			if (frame.tf_eip != IDTVEC(syscall))
+#endif
+				frame.tf_eflags &= ~PSL_T;
 			return;
 #endif
 
@@ -887,6 +901,15 @@ bad:
 		break;
 	}
 
+#if 1
+	if (frame.tf_eflags & PSL_T) {
+		/* traced syscall, raise sig */
+		frame.tf_eflags &= ~PSL_T;
+		if (ISPL(frame.tf_cs) == SEL_UPL) {
+			trapsignal(p, SIGTRAP, 0);
+		}
+	}
+#endif
 	userret(p, &frame, sticks);
 
 #ifdef KTRACE
@@ -980,6 +1003,15 @@ linux_syscall(frame)
 		break;
 	}
 
+#if 1
+	if (frame.tf_eflags & PSL_T) {
+		/* traced syscall, raise sig */
+		frame.tf_eflags &= ~PSL_T;
+		if (ISPL(frame.tf_cs) == SEL_UPL) {
+			trapsignal(p, SIGTRAP, 0);
+		}
+	}
+#endif
 	userret(p, &frame, sticks);
 
 #ifdef KTRACE
diff --git a/sys/compat/linux/linux_misc.c b/sys/compat/linux/linux_misc.c
index bf40786..a9f7e0b 100644
--- a/sys/compat/linux/linux_misc.c
+++ b/sys/compat/linux/linux_misc.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: linux_misc.c,v 1.4 1995/06/08 13:50:52 sos Exp $
+ *  $Id: linux_misc.c,v 1.1 1995/06/25 17:32:37 sos Exp $
  */
 
 #include <i386/linux/linux.h>
@@ -188,7 +188,7 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
     printf("Linux-emul(%d): uselib(%s)\n", p->p_pid, path);
 #endif
 
-    NDINIT(&ni, LOOKUP, FOLLOW, UIO_SYSSPACE, path, p);
+    NDINIT(&ni, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
     if (error = namei(&ni))
 	return error;
 
@@ -196,25 +196,39 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
     if (vnodep == NULL)
 	    return ENOEXEC;
 
-    if (vnodep->v_writecount)
+    if (vnodep->v_writecount) {
+	    VOP_UNLOCK(vnodep);
 	    return ETXTBSY;
+    }
 
-    if (error = VOP_GETATTR(vnodep, &attr, p->p_ucred, p))
-	return error;
+    if (error = VOP_GETATTR(vnodep, &attr, p->p_ucred, p)) {
+	    VOP_UNLOCK(vnodep);
+	    return error;
+    }
 
     if ((vnodep->v_mount->mnt_flag & MNT_NOEXEC)
 	|| ((attr.va_mode & 0111) == 0)
-	|| (attr.va_type != VREG))
+	|| (attr.va_type != VREG)) {
+	    VOP_UNLOCK(vnodep);
 	    return ENOEXEC;
+    }
 
-    if (attr.va_size == 0)
+    if (attr.va_size == 0) {
+	    VOP_UNLOCK(vnodep);
 	    return ENOEXEC;
+    }
 
-    if (error = VOP_ACCESS(vnodep, VEXEC, p->p_ucred, p))
+    if (error = VOP_ACCESS(vnodep, VEXEC, p->p_ucred, p)) {
+	VOP_UNLOCK(vnodep);
 	return error;
+    }
 
-    if (error = VOP_OPEN(vnodep, FREAD, p->p_ucred, p))
+    if (error = VOP_OPEN(vnodep, FREAD, p->p_ucred, p)) {
+	VOP_UNLOCK(vnodep);
 	return error;
+    }
+
+    VOP_UNLOCK(vnodep);	/* lock no longer needed */
 
     error = vm_mmap(kernel_map, (vm_offset_t *)&a_out, 1024,
 	    	    VM_PROT_READ, VM_PROT_READ, 0, (caddr_t)vnodep, 0);
@@ -225,7 +239,7 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
      * Is it a Linux binary ?
      */
     if (((a_out->a_magic >> 16) & 0xff) != 0x64)
-	return -1;
+	return ENOEXEC;
 
     /*
      * Set file/virtual offset based on a.out variant.
@@ -240,7 +254,7 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
 	file_offset = 0;
 	break;
     default:
-	return (-1);
+	return ENOEXEC;
     }
 
     vnodep->v_flag |= VTEXT;
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index 37d8e2e..ec1e937 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)trap.c	7.4 (Berkeley) 5/13/91
- *	$Id: trap.c,v 1.58 1995/07/30 17:49:24 davidg Exp $
+ *	$Id: trap.c,v 1.59 1995/08/21 18:06:48 davidg Exp $
  */
 
 /*
@@ -78,6 +78,11 @@
 int	trap_pfault	__P((struct trapframe *, int));
 void	trap_fatal	__P((struct trapframe *));
 
+extern inthand_t IDTVEC(syscall);
+#ifdef COMPAT_LINUX
+extern inthand_t IDTVEC(linux_syscall);
+#endif
+
 #define MAX_TRAP_MSG		27
 char *trap_msg[] = {
 	"",					/*  0 unused */
@@ -351,14 +356,23 @@ trap(frame)
 
 #ifdef DDB
 		case T_BPTFLT:
+#ifndef DDB_NO_LCALLS
 		case T_TRCTRAP:
+#endif
 			if (kdb_trap (type, 0, &frame))
 				return;
 			break;
-#else
+#endif
+#if !defined (DDB) || defined (DDB_NO_LCALLS)
 		case T_TRCTRAP:	 /* trace trap -- someone single stepping lcall's */
 			/* Q: how do we turn it on again? */
-			frame.tf_eflags &= ~PSL_T;
+#ifdef COMPAT_LINUX
+			if (frame.tf_eip != (int) IDTVEC(syscall) &&
+			    frame.tf_eip != (int) IDTVEC(linux_syscall))
+#else
+			if (frame.tf_eip != IDTVEC(syscall))
+#endif
+				frame.tf_eflags &= ~PSL_T;
 			return;
 #endif
 
@@ -887,6 +901,15 @@ bad:
 		break;
 	}
 
+#if 1
+	if (frame.tf_eflags & PSL_T) {
+		/* traced syscall, raise sig */
+		frame.tf_eflags &= ~PSL_T;
+		if (ISPL(frame.tf_cs) == SEL_UPL) {
+			trapsignal(p, SIGTRAP, 0);
+		}
+	}
+#endif
 	userret(p, &frame, sticks);
 
 #ifdef KTRACE
@@ -980,6 +1003,15 @@ linux_syscall(frame)
 		break;
 	}
 
+#if 1
+	if (frame.tf_eflags & PSL_T) {
+		/* traced syscall, raise sig */
+		frame.tf_eflags &= ~PSL_T;
+		if (ISPL(frame.tf_cs) == SEL_UPL) {
+			trapsignal(p, SIGTRAP, 0);
+		}
+	}
+#endif
 	userret(p, &frame, sticks);
 
 #ifdef KTRACE
diff --git a/sys/i386/linux/linux_misc.c b/sys/i386/linux/linux_misc.c
index bf40786..a9f7e0b 100644
--- a/sys/i386/linux/linux_misc.c
+++ b/sys/i386/linux/linux_misc.c
@@ -25,7 +25,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *  $Id: linux_misc.c,v 1.4 1995/06/08 13:50:52 sos Exp $
+ *  $Id: linux_misc.c,v 1.1 1995/06/25 17:32:37 sos Exp $
  */
 
 #include <i386/linux/linux.h>
@@ -188,7 +188,7 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
     printf("Linux-emul(%d): uselib(%s)\n", p->p_pid, path);
 #endif
 
-    NDINIT(&ni, LOOKUP, FOLLOW, UIO_SYSSPACE, path, p);
+    NDINIT(&ni, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
     if (error = namei(&ni))
 	return error;
 
@@ -196,25 +196,39 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
     if (vnodep == NULL)
 	    return ENOEXEC;
 
-    if (vnodep->v_writecount)
+    if (vnodep->v_writecount) {
+	    VOP_UNLOCK(vnodep);
 	    return ETXTBSY;
+    }
 
-    if (error = VOP_GETATTR(vnodep, &attr, p->p_ucred, p))
-	return error;
+    if (error = VOP_GETATTR(vnodep, &attr, p->p_ucred, p)) {
+	    VOP_UNLOCK(vnodep);
+	    return error;
+    }
 
     if ((vnodep->v_mount->mnt_flag & MNT_NOEXEC)
 	|| ((attr.va_mode & 0111) == 0)
-	|| (attr.va_type != VREG))
+	|| (attr.va_type != VREG)) {
+	    VOP_UNLOCK(vnodep);
 	    return ENOEXEC;
+    }
 
-    if (attr.va_size == 0)
+    if (attr.va_size == 0) {
+	    VOP_UNLOCK(vnodep);
 	    return ENOEXEC;
+    }
 
-    if (error = VOP_ACCESS(vnodep, VEXEC, p->p_ucred, p))
+    if (error = VOP_ACCESS(vnodep, VEXEC, p->p_ucred, p)) {
+	VOP_UNLOCK(vnodep);
 	return error;
+    }
 
-    if (error = VOP_OPEN(vnodep, FREAD, p->p_ucred, p))
+    if (error = VOP_OPEN(vnodep, FREAD, p->p_ucred, p)) {
+	VOP_UNLOCK(vnodep);
 	return error;
+    }
+
+    VOP_UNLOCK(vnodep);	/* lock no longer needed */
 
     error = vm_mmap(kernel_map, (vm_offset_t *)&a_out, 1024,
 	    	    VM_PROT_READ, VM_PROT_READ, 0, (caddr_t)vnodep, 0);
@@ -225,7 +239,7 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
      * Is it a Linux binary ?
      */
     if (((a_out->a_magic >> 16) & 0xff) != 0x64)
-	return -1;
+	return ENOEXEC;
 
     /*
      * Set file/virtual offset based on a.out variant.
@@ -240,7 +254,7 @@ linux_uselib(struct proc *p, struct linux_uselib_args *args, int *retval)
 	file_offset = 0;
 	break;
     default:
-	return (-1);
+	return ENOEXEC;
     }
 
     vnodep->v_flag |= VTEXT;
diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c
index 37d8e2e..ec1e937 100644
--- a/sys/kern/subr_trap.c
+++ b/sys/kern/subr_trap.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)trap.c	7.4 (Berkeley) 5/13/91
- *	$Id: trap.c,v 1.58 1995/07/30 17:49:24 davidg Exp $
+ *	$Id: trap.c,v 1.59 1995/08/21 18:06:48 davidg Exp $
  */
 
 /*
@@ -78,6 +78,11 @@
 int	trap_pfault	__P((struct trapframe *, int));
 void	trap_fatal	__P((struct trapframe *));
 
+extern inthand_t IDTVEC(syscall);
+#ifdef COMPAT_LINUX
+extern inthand_t IDTVEC(linux_syscall);
+#endif
+
 #define MAX_TRAP_MSG		27
 char *trap_msg[] = {
 	"",					/*  0 unused */
@@ -351,14 +356,23 @@ trap(frame)
 
 #ifdef DDB
 		case T_BPTFLT:
+#ifndef DDB_NO_LCALLS
 		case T_TRCTRAP:
+#endif
 			if (kdb_trap (type, 0, &frame))
 				return;
 			break;
-#else
+#endif
+#if !defined (DDB) || defined (DDB_NO_LCALLS)
 		case T_TRCTRAP:	 /* trace trap -- someone single stepping lcall's */
 			/* Q: how do we turn it on again? */
-			frame.tf_eflags &= ~PSL_T;
+#ifdef COMPAT_LINUX
+			if (frame.tf_eip != (int) IDTVEC(syscall) &&
+			    frame.tf_eip != (int) IDTVEC(linux_syscall))
+#else
+			if (frame.tf_eip != IDTVEC(syscall))
+#endif
+				frame.tf_eflags &= ~PSL_T;
 			return;
 #endif
 
@@ -887,6 +901,15 @@ bad:
 		break;
 	}
 
+#if 1
+	if (frame.tf_eflags & PSL_T) {
+		/* traced syscall, raise sig */
+		frame.tf_eflags &= ~PSL_T;
+		if (ISPL(frame.tf_cs) == SEL_UPL) {
+			trapsignal(p, SIGTRAP, 0);
+		}
+	}
+#endif
 	userret(p, &frame, sticks);
 
 #ifdef KTRACE
@@ -980,6 +1003,15 @@ linux_syscall(frame)
 		break;
 	}
 
+#if 1
+	if (frame.tf_eflags & PSL_T) {
+		/* traced syscall, raise sig */
+		frame.tf_eflags &= ~PSL_T;
+		if (ISPL(frame.tf_cs) == SEL_UPL) {
+			trapsignal(p, SIGTRAP, 0);
+		}
+	}
+#endif
 	userret(p, &frame, sticks);
 
 #ifdef KTRACE