From 5fd6637b4d3f8e4e47227db92daa5dc39226aa12 Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Sun, 23 Mar 2008 19:43:41 +0000
Subject: [PATCH] * Decide whether to use BeOS style symbol resolution at run
 time   depending on the gcc version of the executable. * Adjusted
 non-BeOS-style symbol resolution so that add-ons and   dynamically loaded
 libraries find symbols in the executable.

This change re-enables support for undefined symbols.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24537 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../private/runtime_loader/runtime_loader.h   |  5 ++
 src/system/runtime_loader/Jamfile             |  3 +-
 src/system/runtime_loader/elf.cpp             | 46 ++++++++++++++-----
 3 files changed, 41 insertions(+), 13 deletions(-)

diff --git a/headers/private/runtime_loader/runtime_loader.h b/headers/private/runtime_loader/runtime_loader.h
index 55259c1382..15266e3390 100644
--- a/headers/private/runtime_loader/runtime_loader.h
+++ b/headers/private/runtime_loader/runtime_loader.h
@@ -74,6 +74,11 @@ typedef struct image_queue_t {
 	image_t *tail;
 } image_queue_t;
 
+// image_t::flags
+#define	IMAGE_FLAG_RTLD_MASK			0x03
+			// RTLD_{LAZY,NOW} | RTLD_{LOCAL,GLOBAL}
+#define	IMAGE_FLAG_R5_SYMBOL_RESOLUTION	0x04
+
 #define STRING(image, offset) ((char *)(&(image)->strtab[(offset)]))
 #define SYMNAME(image, sym) STRING(image, (sym)->st_name)
 #define SYMBOL(image, num) ((struct Elf32_Sym *)&(image)->syms[num])
diff --git a/src/system/runtime_loader/Jamfile b/src/system/runtime_loader/Jamfile
index deee55e771..31a704e805 100644
--- a/src/system/runtime_loader/Jamfile
+++ b/src/system/runtime_loader/Jamfile
@@ -8,8 +8,7 @@ UseHeaders $(TARGET_PRIVATE_KERNEL_HEADERS) : true ;
 SubDirCcFlags -fno-builtin ;
 SubDirC++Flags -fno-builtin -fno-exceptions ;
 
-# default to BeOS style symbol resolution
-DEFINES += BEOS_STYLE_SYMBOLS_RESOLUTION
+DEFINES +=
 	KMESSAGE_CONTAINER_ONLY
 	_LOADER_MODE
 ;
diff --git a/src/system/runtime_loader/elf.cpp b/src/system/runtime_loader/elf.cpp
index 8e689946aa..eaa3b6ed94 100644
--- a/src/system/runtime_loader/elf.cpp
+++ b/src/system/runtime_loader/elf.cpp
@@ -82,12 +82,6 @@ static uint32 sLoadedImageCount = 0;
 static image_t *sProgramImage;
 static KMessage sErrorMessage;
 
-#ifdef BEOS_STYLE_SYMBOLS_RESOLUTION
-static bool sResolveSymbolsBeOSStyle = true;
-#else
-static bool sResolveSymbolsBeOSStyle = false;
-#endif
-
 // a recursive lock
 static sem_id rld_sem;
 static thread_id rld_sem_owner;
@@ -280,18 +274,28 @@ find_loaded_image_by_id(image_id id)
 }
 
 
-static const char *
-get_program_path()
+static image_t*
+get_program_image()
 {
 	for (image_t *image = sLoadedImages.head; image; image = image->next) {
 		if (image->type == B_APP_IMAGE)
-			return image->path;
+			return image;
 	}
 
 	return NULL;
 }
 
 
+static const char *
+get_program_path()
+{
+	if (image_t* image = get_program_image())
+		return image->path;
+
+	return NULL;
+}
+
+
 static status_t
 parse_elf_header(struct Elf32_Ehdr *eheader, int32 *_pheaderSize,
 	int32 *_sheaderSize)
@@ -1020,8 +1024,20 @@ find_undefined_symbol(image_t* rootImage, image_t* image, const char* name,
 	// If not simulating BeOS style symbol resolution, undefined symbols are
 	// search recursively starting from the root image. (Note, breadth first
 	// might be better than the depth first use here.)
-	if (!sResolveSymbolsBeOSStyle)
-		return find_symbol_recursively(rootImage, name, foundInImage);
+	if ((rootImage->flags & IMAGE_FLAG_R5_SYMBOL_RESOLUTION) == 0) {
+		Elf32_Sym* symbol = find_symbol_recursively(rootImage, name,
+			foundInImage);
+		if (symbol != NULL)
+			return symbol;
+
+		// If the root image is not the program image (i.e. it is a dynamically
+		// loaded add-on or library), we try the program image hierarchy too.
+		image_t* programImage = get_program_image();
+		if (rootImage != programImage)
+			return find_symbol_recursively(programImage, name, foundInImage);
+
+		return NULL;
+	}
 
 	// BeOS style symbol resolution: It is sufficient to check the direct
 	// dependencies. The linker would have complained, if the symbol wasn't
@@ -1256,6 +1272,14 @@ load_container(char const *name, image_type type, const char *rpath, image_t **_
 		// not really fatal, actually
 	}
 
+	// init gcc version dependent image flags
+	// symbol resolution strategy (fallback is R5-style, if version is
+	// unavailable)
+	if (image->gcc_version.major == 0
+		|| image->gcc_version.major == 2 && image->gcc_version.middle < 95) {
+		image->flags |= IMAGE_FLAG_R5_SYMBOL_RESOLUTION;
+	}
+
 	status = map_image(fd, path, image, type == B_APP_IMAGE);
 	if (status < B_OK) {
 		FATAL("Could not map image: %s\n", strerror(status));