Implement dl_iterate_phdr() for static PIE executables using info extracted

from the aux vector.

ok patrick@ kettenis@

3 files changed, 74 insertions, 4 deletions

diff --git a/lib/libc/dlfcn/dlfcn_stubs.c b/lib/libc/dlfcn/dlfcn_stubs.c
index 59b8e1fd1c9..e04a2aa0706 100644
--- a/lib/libc/dlfcn/dlfcn_stubs.c
+++ b/lib/libc/dlfcn/dlfcn_stubs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dlfcn_stubs.c,v 1.13 2015/11/01 03:00:01 guenther Exp $	*/
+/*	$OpenBSD: dlfcn_stubs.c,v 1.14 2016/09/06 18:49:34 guenther Exp $	*/
 
 /*
  * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@@ -26,7 +26,11 @@
  *
  */
 
+#include <sys/types.h>
 #include <stddef.h>
+#include <link.h>
+
+#include "init.h"
 
 /*
  *	All functions here are just stubs that will be overridden
@@ -45,7 +49,6 @@ char 	*dlerror(void) __attribute__((weak));
 struct dl_info;
 int	dladdr(const void *addr, struct dl_info *info) __attribute__((weak));
 
-struct dl_phdr_info;
 int	 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),	    void *date) __attribute__((weak));
 
 #include <stdio.h>
@@ -87,6 +90,11 @@ int
 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
 	void *data)
 {
+#ifndef PIC
+	if (_static_phdr_info.dlpi_phdr != NULL)
+		return callback(&_static_phdr_info, sizeof(_static_phdr_info),
+		    data);
+#endif /* !PIC */
 	return -1;
 }
 
@@ -96,3 +104,30 @@ dladdr(const void *addr, struct dl_info *info)
 	printf("Wrong dl symbols!\n");
 	return -1;
 }
+
+/* Thread Local Storage argument structure */
+typedef struct {
+	unsigned long int ti_module;
+	unsigned long int ti_offset;
+} tls_index;
+
+void	*__tls_get_addr(tls_index *) __attribute__((weak));
+#ifdef __i386
+void	*___tls_get_addr(tls_index *) __attribute__((weak, __regparm__(1)));
+#endif
+
+#if defined(__amd64) || defined(__i386) || defined(__sparc64)
+void *
+__tls_get_addr(tls_index *ti)
+{
+	return NULL;
+}
+
+#ifdef __i386
+__attribute__((__regparm__(1))) void *
+___tls_get_addr(tls_index *ti)
+{
+	return NULL;
+}
+#endif /* __i386 */
+#endif /* arch with TLS support enabled */
diff --git a/lib/libc/dlfcn/init.c b/lib/libc/dlfcn/init.c
index 3147f9ba7f1..c791c88610e 100644
--- a/lib/libc/dlfcn/init.c
+++ b/lib/libc/dlfcn/init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init.c,v 1.4 2016/05/07 19:05:22 guenther Exp $ */
+/*	$OpenBSD: init.c,v 1.5 2016/09/06 18:49:34 guenther Exp $ */
 /*
  * Copyright (c) 2014,2015 Philip Guenther <guenther@openbsd.org>
  *
@@ -19,7 +19,6 @@
 #define _DYN_LOADER
 
 #include <sys/types.h>
-#include <sys/exec_elf.h>
 #include <sys/syscall.h>
 
 #ifndef PIC
@@ -28,10 +27,13 @@
 
 #include <tib.h>
 #include <limits.h>		/* NAME_MAX */
+#include <link.h>
 #include <stdlib.h>		/* atexit */
 #include <string.h>
 #include <unistd.h>
 
+#include "init.h"
+
 /* XXX should be in an include file shared with csu */
 char	***_csu_finish(char **_argv, char **_envp, void (*_cleanup)(void));
 
@@ -47,6 +49,8 @@ char	*__progname __attribute__((weak)) = NULL;
 
 
 #ifndef PIC
+struct dl_phdr_info	_static_phdr_info = { .dlpi_name = "a.out" };
+
 static inline void early_static_init(char **_argv, char **_envp);
 static inline void setup_static_tib(Elf_Phdr *_phdr, int _phnum);
 #endif /* PIC */
@@ -79,11 +83,16 @@ _csu_finish(char **argv, char **envp, void (*cleanup)(void))
 			_pagesize = aux->au_v;
 			break;
 #ifndef PIC
+		case AUX_base:
+			_static_phdr_info.dlpi_addr = aux->au_v;
+			break;
 		case AUX_phdr:
 			phdr = (void *)aux->au_v;
+			_static_phdr_info.dlpi_phdr = phdr;
 			break;
 		case AUX_phnum:
 			phnum = aux->au_v;
+			_static_phdr_info.dlpi_phnum = phnum;
 			break;
 #endif /* !PIC */
 		}
diff --git a/lib/libc/dlfcn/init.h b/lib/libc/dlfcn/init.h
new file mode 100644
index 00000000000..770c17ff632
--- /dev/null
+++ b/lib/libc/dlfcn/init.h
@@ -0,0 +1,26 @@
+/*	$OpenBSD: init.h,v 1.1 2016/09/06 18:49:34 guenther Exp $	*/
+/*
+ * Copyright (c) 2016 Philip Guenther <guenther@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef INIT_H
+#define	INIT_H
+
+__BEGIN_HIDDEN_DECLS
+/* shared between dl_iterate_phdr() and _csu_finish() in static builds */
+extern struct dl_phdr_info	_static_phdr_info;
+__END_HIDDEN_DECLS
+
+#endif /* !INIT_H */