Add an additional field to the elf brandinfo structure to support

quicker exec-time replacement of the elf interpreter on an emulation
environment where an entire /compat/* tree isn't really warranted.

sys/alpha/alpha/elf_machdep.c

@@ -81,15 +81,31 @@ static Elf64_Brandinfo freebsd_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_ALPHA,
 						"FreeBSD",
-						"",
+						NULL,
 						"/libexec/ld-elf.so.1",
-						&elf64_freebsd_sysvec
+						&elf64_freebsd_sysvec,
+						NULL,
 					  };
 
 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf64_insert_brand_entry,
 	&freebsd_brand_info);
 
+static Elf64_Brandinfo freebsd_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_ALPHA,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&elf64_freebsd_sysvec,
+						NULL,
+					  };
+
+SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf64_insert_brand_entry,
+	&freebsd_brand_oinfo);
+
+
 /* Process one elf relocation with addend. */
 static int
 elf_reloc_internal(linker_file_t lf, const void *data, int type, int local)

sys/alpha/linux/linux_sysvec.c

@@ -210,7 +210,8 @@ static Elf64_Brandinfo linux_brand = {
 					"Linux",
 					"/compat/linux",
 					"/lib/ld-linux.so.1",
-					&elf_linux_sysvec
+					&elf_linux_sysvec,
+					NULL,
 				 };
 
 static Elf64_Brandinfo linux_glibc2brand = {
@@ -219,7 +220,8 @@ static Elf64_Brandinfo linux_glibc2brand = {
 					"Linux",
 					"/compat/linux",
 					"/lib/ld-linux.so.2",
-					&elf_linux_sysvec
+					&elf_linux_sysvec,
+					NULL,
 				 };
 
 Elf64_Brandinfo *linux_brandlist[] = {

sys/amd64/amd64/elf_machdep.c

@@ -78,15 +78,30 @@ static Elf64_Brandinfo freebsd_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_X86_64,
 						"FreeBSD",
-						"",
+						NULL,
 						"/libexec/ld-elf.so.1",
-						&elf64_freebsd_sysvec
+						&elf64_freebsd_sysvec,
+						NULL,
 					  };
 
 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf64_insert_brand_entry,
 	&freebsd_brand_info);
 
+static Elf64_Brandinfo freebsd_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_X86_64,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&elf64_freebsd_sysvec,
+						NULL,
+					  };
+
+SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf64_insert_brand_entry,
+	&freebsd_brand_oinfo);
+
 /* Process one elf relocation with addend. */
 static int
 elf_reloc_internal(linker_file_t lf, const void *data, int type, int local)

sys/compat/ia32/ia32_sysvec.c

@@ -129,21 +129,34 @@ struct sysentvec ia32_freebsd_sysvec = {
 };
 
 
-const char freebsd32_emul_path[] = "/compat/ia32";
-
 static Elf32_Brandinfo ia32_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_386,
 						"FreeBSD",
-						"/compat/ia32",
+						NULL,
-						"/usr/libexec/ld-elf.so.1",
+						"/libexec/ld-elf.so.1",
-						&ia32_freebsd_sysvec
+						&ia32_freebsd_sysvec,
+						"/libexec/ld-elf-32.so.1",
 					  };
 
 SYSINIT(ia32, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf32_insert_brand_entry,
 	&ia32_brand_info);
 
+static Elf32_Brandinfo ia32_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_386,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&ia32_freebsd_sysvec,
+						"/usr/libexec/ld-elf-32.so.1",
+					  };
+
+SYSINIT(oia32, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf32_insert_brand_entry,
+	&ia32_brand_oinfo);
+
 /* XXX may be freebsd32 MI */
 static register_t *
 ia32_copyout_strings(struct image_params *imgp)

sys/compat/svr4/svr4_sysvec.c

@@ -199,7 +199,8 @@ Elf32_Brandinfo svr4_brand = {
   "SVR4",
   svr4_emul_path,
   "/lib/libc.so.1",
-  &svr4_sysvec
+  &svr4_sysvec,
+  NULL,
 };
 
 const char      svr4_emul_path[] = "/compat/svr4";

sys/i386/i386/elf_machdep.c

@@ -78,15 +78,30 @@ static Elf32_Brandinfo freebsd_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_386,
 						"FreeBSD",
-						"",
+						NULL,
 						"/libexec/ld-elf.so.1",
-						&elf32_freebsd_sysvec
+						&elf32_freebsd_sysvec,
+						NULL,
 					  };
 
 SYSINIT(elf32, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf32_insert_brand_entry,
 	&freebsd_brand_info);
 
+static Elf32_Brandinfo freebsd_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_386,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&elf32_freebsd_sysvec,
+						NULL,
+					  };
+
+SYSINIT(oelf32, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf32_insert_brand_entry,
+	&freebsd_brand_oinfo);
+
 /* Process one elf relocation with addend. */
 static int
 elf_reloc_internal(linker_file_t lf, const void *data, int type, int local)

sys/i386/linux/linux_sysvec.c

@@ -899,7 +899,8 @@ static Elf32_Brandinfo linux_brand = {
 					"Linux",
 					"/compat/linux",
 					"/lib/ld-linux.so.1",
-					&elf_linux_sysvec
+					&elf_linux_sysvec,
+					NULL,
 				 };
 
 static Elf32_Brandinfo linux_glibc2brand = {
@@ -908,7 +909,8 @@ static Elf32_Brandinfo linux_glibc2brand = {
 					"Linux",
 					"/compat/linux",
 					"/lib/ld-linux.so.2",
-					&elf_linux_sysvec
+					&elf_linux_sysvec,
+					NULL,
 				 };
 
 Elf32_Brandinfo *linux_brandlist[] = {

sys/ia64/ia64/elf_machdep.c

@@ -84,15 +84,30 @@ static Elf64_Brandinfo freebsd_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_IA_64,
 						"FreeBSD",
-						"",
+						NULL,
 						"/libexec/ld-elf.so.1",
-						&elf64_freebsd_sysvec
+						&elf64_freebsd_sysvec,
+						NULL,
 					  };
 
 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf64_insert_brand_entry,
 	&freebsd_brand_info);
 
+static Elf64_Brandinfo freebsd_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_IA_64,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&elf64_freebsd_sysvec,
+						NULL,
+					  };
+
+SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf64_insert_brand_entry,
+	&freebsd_brand_oinfo);
+
 Elf_Addr link_elf_get_gp(linker_file_t);
 
 extern Elf_Addr fptr_storage[];

sys/kern/imgact_elf.c

@@ -708,6 +708,8 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
 		goto fail;
 	}
 	sv = brand_info->sysvec;
+	if (interp != NULL && brand_info->interp_newpath != NULL)
+		interp = brand_info->interp_newpath;
 
 	if ((error = exec_extract_strings(imgp)) != 0)
 		goto fail;
@@ -818,21 +820,24 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
 	imgp->entry_addr = entry;
 
 	imgp->proc->p_sysent = sv;
-	if (interp != NULL) {
+	if (interp != NULL && brand_info->emul_path != NULL &&
+	    brand_info->emul_path[0] != '\0') {
 		path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 		snprintf(path, MAXPATHLEN, "%s%s", brand_info->emul_path,
 		    interp);
-		if ((error = __elfN(load_file)(imgp->proc, path, &addr,
+		error = __elfN(load_file)(imgp->proc, path, &addr,
-		    &imgp->entry_addr, sv->sv_pagesize)) != 0) {
+		    &imgp->entry_addr, sv->sv_pagesize);
-			if ((error = __elfN(load_file)(imgp->proc, interp,
-			    &addr, &imgp->entry_addr, sv->sv_pagesize)) != 0) {
-				uprintf("ELF interpreter %s not found\n",
-				    path);
-				free(path, M_TEMP);
-				goto fail;
-			}
-		}
 		free(path, M_TEMP);
+		if (error == 0)
+			interp = NULL;
+	}
+	if (interp != NULL) {
+		error = __elfN(load_file)(imgp->proc, interp, &addr,
+		    &imgp->entry_addr, sv->sv_pagesize);
+		if (error != 0) {
+			uprintf("ELF interpreter %s not found\n", interp);
+			goto fail;
+		}
 	}
 
 	/*

sys/powerpc/powerpc/elf_machdep.c

@@ -80,15 +80,30 @@ static Elf32_Brandinfo freebsd_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_PPC,
 						"FreeBSD",
-						"",
+						NULL,
 						"/libexec/ld-elf.so.1",
-						&elf32_freebsd_sysvec
+						&elf32_freebsd_sysvec,
+						NULL,
 					  };
 
 SYSINIT(elf32, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf32_insert_brand_entry,
 	&freebsd_brand_info);
 
+static Elf32_Brandinfo freebsd_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_PPC,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&elf32_freebsd_sysvec,
+						NULL,
+					  };
+
+SYSINIT(oelf32, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf32_insert_brand_entry,
+	&freebsd_brand_oinfo);
+
 /* Process one elf relocation with addend. */
 static int
 elf_reloc_internal(linker_file_t lf, const void *data, int type, int local)

sys/sparc64/sparc64/elf_machdep.c

@@ -91,15 +91,30 @@ static Elf64_Brandinfo freebsd_brand_info = {
 						ELFOSABI_FREEBSD,
 						EM_SPARCV9,
 						"FreeBSD",
-						"",
+						NULL,
 						"/libexec/ld-elf.so.1",
-						&elf64_freebsd_sysvec
+						&elf64_freebsd_sysvec,
+						NULL,
 					  };
 
 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_ANY,
 	(sysinit_cfunc_t) elf64_insert_brand_entry,
 	&freebsd_brand_info);
 
+static Elf64_Brandinfo freebsd_brand_oinfo = {
+						ELFOSABI_FREEBSD,
+						EM_SPARCV9,
+						"FreeBSD",
+						NULL,
+						"/usr/libexec/ld-elf.so.1",
+						&elf64_freebsd_sysvec,
+						NULL,
+					  };
+
+SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
+	(sysinit_cfunc_t) elf64_insert_brand_entry,
+	&freebsd_brand_oinfo);
+
 /*
  * The following table holds for each relocation type:
  *	- the width in bits of the memory location the relocation

sys/sys/imgact_elf.h

@@ -61,13 +61,14 @@ typedef struct {
 	const char *compat_3_brand;	/* pre Binutils 2.10 method (FBSD 3) */
 	const char *emul_path;
 	const char *interp_path;
-        struct sysentvec *sysvec;
+	struct sysentvec *sysvec;
+	const char *interp_newpath;
 } __ElfN(Brandinfo);
 
 __ElfType(Auxargs);
 __ElfType(Brandinfo);
 
-#define MAX_BRANDS      8
+#define MAX_BRANDS	8
 
 int	__elfN(brand_inuse)(Elf_Brandinfo *entry);
 int	__elfN(insert_brand_entry)(Elf_Brandinfo *entry);