cg: lift restriction of 1st arg to bcopy() not being alloca

The documentation states that the source address is not allowed to be
within the scratch memory region, but the legacy implementation does
not actually enforce that restriction, nor does it seem necessary.

This patch also moves bcopy tests into their own directory.

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Eugene Loh <eugene.loh@oracle.com>

libdtrace/dt_cg.c

@@ -1,6 +1,6 @@
 /*
  * Oracle Linux DTrace.
- * Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2023, Oracle and/or its affiliates. All rights reserved.
  * Licensed under the Universal Permissive License v 1.0 as shown at
  * http://oss.oracle.com/licenses/upl.
  */
@@ -1040,14 +1040,20 @@ dt_cg_alloca_ptr(dt_irlist_t *dlp, dt_regset_t *drp, int dreg, int sreg)
  * alloca pointer value into a real pointer.
  */
 static void
-dt_cg_check_ptr_arg(dt_irlist_t *dlp, dt_regset_t *drp, dt_node_t *dnp)
+dt_cg_check_ptr_arg(dt_irlist_t *dlp, dt_regset_t *drp, dt_node_t *dnp,
+		    dt_node_t *size)
 {
 	if (dnp->dn_flags & DT_NF_ALLOCA) {
-		dtrace_diftype_t	vtype;
+		if (size == NULL) {
+			dtrace_diftype_t	vtype;
+
+			dt_node_diftype(yypcb->pcb_hdl, dnp, &vtype);
+			dt_cg_alloca_access_check(dlp, drp, dnp->dn_reg,
+						  DT_ISIMM, vtype.dtdt_size);
+		} else
+			dt_cg_alloca_access_check(dlp, drp, dnp->dn_reg,
+						  DT_ISREG, size->dn_reg);
 
-		dt_node_diftype(yypcb->pcb_hdl, dnp, &vtype);
-		dt_cg_alloca_access_check(dlp, drp, dnp->dn_reg,
-					  DT_ISIMM, vtype.dtdt_size);
 		dt_cg_alloca_ptr(dlp, drp, dnp->dn_reg, dnp->dn_reg);
 	} else
 		dt_cg_check_notnull(dlp, drp, dnp->dn_reg);
@@ -3892,7 +3898,7 @@ dt_cg_subr_arg_to_tstring(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
 	/* (its type matters only as to whether we check it is null */
 	dt_cg_node(arg, dlp, drp);
 	if (dt_node_is_pointer(arg) || dt_node_is_string(arg))
-		dt_cg_check_ptr_arg(dlp, drp, arg);
+		dt_cg_check_ptr_arg(dlp, drp, arg, NULL);
 
 	/* allocate the temporary string */
 	dnp->dn_reg = dt_regset_alloc(drp);
@@ -3950,9 +3956,9 @@ dt_cg_subr_index(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	TRACE_REGSET("    subr-index:Begin");
 
 	dt_cg_node(s, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, s);
+	dt_cg_check_ptr_arg(dlp, drp, s, NULL);
 	dt_cg_node(t, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, t);
+	dt_cg_check_ptr_arg(dlp, drp, t, NULL);
 	if (start != NULL)
 		dt_cg_node(start, dlp, drp);
 
@@ -4167,9 +4173,9 @@ dt_cg_subr_rindex(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 	/* evaluate arguments to D subroutine rindex() */
 	dt_cg_node(s, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, s);
+	dt_cg_check_ptr_arg(dlp, drp, s, NULL);
 	dt_cg_node(t, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, t);
+	dt_cg_check_ptr_arg(dlp, drp, t, NULL);
 	if (start != NULL)
 		dt_cg_node(start, dlp, drp);
 
@@ -4394,13 +4400,7 @@ dt_cg_subr_bcopy_impl(dt_node_t *dnp, dt_node_t *dst, dt_node_t *src,
 
 	/* Validate the source pointer. */
 	dt_cg_node(src, dlp, drp);
-	if (src->dn_flags & DT_NF_ALLOCA)
-		dnerror(src, D_PROTO_ARG,
-			"%s( ) argument #1 is incompatible with prototype:\n"
-			"\tprototype: non-alloca pointer\n"
-			"\t argument: alloca pointer\n",
-			is_bcopy ? "bcopy" : "copyinto");
-	dt_cg_check_notnull(dlp, drp, src->dn_reg);
+	dt_cg_check_ptr_arg(dlp, drp, src, size);
 
 	/* Validate the destination pointer. */
 	dt_cg_node(dst, dlp, drp);
@@ -4410,11 +4410,7 @@ dt_cg_subr_bcopy_impl(dt_node_t *dnp, dt_node_t *dst, dt_node_t *src,
 			"\tprototype: alloca pointer\n"
 			"\t argument: non-alloca pointer\n",
 			is_bcopy ? "bcopy" : "copyinto", is_bcopy ? 2 : 3);
-	/* The dst will be NULL-checked in the alloca access check below. */
-
-	dt_cg_alloca_access_check(dlp, drp, dst->dn_reg,
-				  DT_ISREG, size->dn_reg);
-	dt_cg_alloca_ptr(dlp, drp, dst->dn_reg, dst->dn_reg);
+	dt_cg_check_ptr_arg(dlp, drp, dst, size);
 
 	if (dt_regset_xalloc_args(drp) == -1)
 		longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
@@ -4594,7 +4590,7 @@ dt_cg_subr_strchr(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 	TRACE_REGSET("    subr-strchr:Begin");
 	dt_cg_node(str, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, str);
+	dt_cg_check_ptr_arg(dlp, drp, str, NULL);
 	dt_cg_node(chr, dlp, drp);
 
 	if (dt_regset_xalloc_args(drp) == -1)
@@ -4650,7 +4646,7 @@ dt_cg_subr_strrchr(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 	TRACE_REGSET("    subr-strrchr:Begin");
 	dt_cg_node(str, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, str);
+	dt_cg_check_ptr_arg(dlp, drp, str, NULL);
 	dt_cg_node(chr, dlp, drp);
 
 	if (dt_regset_xalloc_args(drp) == -1)
@@ -4701,7 +4697,7 @@ dt_cg_subr_strlen(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	TRACE_REGSET("    subr-strlen:Begin");
 
 	dt_cg_node(str, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, str);
+	dt_cg_check_ptr_arg(dlp, drp, str, NULL);
 
 	if (dt_regset_xalloc_args(drp) == -1)
 		longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
@@ -4735,9 +4731,9 @@ dt_cg_subr_strjoin(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	TRACE_REGSET("    subr-strjoin:Begin");
 
 	dt_cg_node(s1, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, s1);
+	dt_cg_check_ptr_arg(dlp, drp, s1, NULL);
 	dt_cg_node(s2, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, s2);
+	dt_cg_check_ptr_arg(dlp, drp, s2, NULL);
 
 	/*
 	 * The result needs to be a temporary string, so we request one.
@@ -4782,9 +4778,9 @@ dt_cg_subr_strstr(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 	/* get args */
 	dt_cg_node(s, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, s);
+	dt_cg_check_ptr_arg(dlp, drp, s, NULL);
 	dt_cg_node(t, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, t);
+	dt_cg_check_ptr_arg(dlp, drp, t, NULL);
 
 	/* call dt_index() call */
 	if (dt_regset_xalloc_args(drp) == -1)
@@ -4885,7 +4881,7 @@ dt_cg_subr_strtok(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	if (str->dn_op != DT_TOK_INT || str->dn_value != 0) {
 		/* string is present:  copy it to internal state */
 		dt_cg_node(str, dlp, drp);
-		dt_cg_check_ptr_arg(dlp, drp, str);
+		dt_cg_check_ptr_arg(dlp, drp, str, NULL);
 
 		if (dt_regset_xalloc_args(drp) == -1)
 			longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
@@ -4914,7 +4910,7 @@ dt_cg_subr_strtok(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 	/* get delimiters */
 	dt_cg_node(del, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, del);
+	dt_cg_check_ptr_arg(dlp, drp, del, NULL);
 
 	/* allocate temporary string for result */
 	dnp->dn_reg = dt_regset_alloc(drp);
@@ -4965,7 +4961,7 @@ dt_cg_subr_substr(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	TRACE_REGSET("    subr-substr:Begin");
 
 	dt_cg_node(str, dlp, drp);
-	dt_cg_check_ptr_arg(dlp, drp, str);
+	dt_cg_check_ptr_arg(dlp, drp, str, NULL);
 	dt_cg_node(idx, dlp, drp);
 	if (cnt != NULL)
 		dt_cg_node(cnt, dlp, drp);
@@ -5415,7 +5411,7 @@ dt_cg_node(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 	case DT_TOK_STRINGOF:
 		dt_cg_node(dnp->dn_child, dlp, drp);
-		dt_cg_check_ptr_arg(dlp, drp, dnp->dn_child);
+		dt_cg_check_ptr_arg(dlp, drp, dnp->dn_child, NULL);
 		dnp->dn_reg = dnp->dn_child->dn_reg;
 		break;
 

test/unittest/funcs/bcopy/err.badbcopy.r

@@ -0,0 +1,4 @@
+-- @@stderr --
+dtrace: failed to compile script test/unittest/funcs/bcopy/err.badbcopy.d: line 26: bcopy( ) argument #2 is incompatible with prototype:
+	prototype: alloca pointer
+	 argument: non-alloca pointer

test/unittest/funcs/bcopy/err.badbcopy2.r

@@ -0,0 +1,4 @@
+-- @@stderr --
+dtrace: failed to compile script test/unittest/funcs/bcopy/err.badbcopy2.d: line 25: bcopy( ) argument #2 is incompatible with prototype:
+	prototype: alloca pointer
+	 argument: non-alloca pointer

test/unittest/funcs/bcopy/err.badbcopy3.r

@@ -0,0 +1,4 @@
+-- @@stderr --
+dtrace: failed to compile script test/unittest/funcs/bcopy/err.badbcopy3.d: line 22: bcopy( ) argument #2 is incompatible with prototype:
+	prototype: alloca pointer
+	 argument: non-alloca pointer

test/unittest/funcs/bcopy/err.badbcopy7.d

@@ -0,0 +1,28 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: bcopy from an alloca pointer is subject to size checks
+ *
+ * SECTION: Actions and Subroutines/alloca();
+ *	    Actions and Subroutines/bcopy()
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	d = alloca(20);
+	s = alloca(10);
+	bcopy(s, d, 20);
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}

test/unittest/funcs/bcopy/err.badbcopy8.r

@@ -0,0 +1,3 @@
+
+-- @@stderr --
+dtrace: error on enabled probe ID 3 (ID 1: dtrace:::BEGIN): invalid size ({ptr}) in action #1 at BPF pc NNN

test/unittest/funcs/err.badbcopy7.d → test/unittest/funcs/bcopy/tst.bcopy2.d

@@ -6,8 +6,8 @@
  */
 
 /*
- * ASSERTION:
- *	bcopy should not copy when the source is scratch space
+ * ASSERTION: bcopy to scratch space is allowed (even though documentation
+ *	      claims that it is not)
  *
  * SECTION: Actions and Subroutines/alloca();
  * 	Actions and Subroutines/bcopy()
@@ -16,14 +16,13 @@
 
 #pragma D option quiet
 
-
 BEGIN
 {
-	ptr = alloca(sizeof(unsigned long));
+	ptr = (unsigned long *)alloca(sizeof(unsigned long));
 	bcopy((void *)&`max_pfn, ptr, sizeof(unsigned long));
-	ptr2 = alloca(sizeof(unsigned long));
+	ptr2 = (unsigned long *)alloca(sizeof(unsigned long));
 	bcopy(ptr, ptr2, sizeof(unsigned long));
-	exit(0);
+	exit(*ptr == *ptr2 ? 0 : 1);
 }
 
 ERROR