From 92fc0e8e46352a593c3ce7f87292ee1c4ee4c4e4 Mon Sep 17 00:00:00 2001
From: johannst <johannst@users.noreply.github.com>
Date: Sat, 6 Apr 2024 21:17:19 +0000
Subject: deploy: 6d2292f2431ec9405b8789c28c81e8e711c15b2d
---
development/ldso/deepbind/.gitignore | 2 ++
development/ldso/deepbind/Makefile | 19 +++++++++++++++++
development/ldso/deepbind/lib.c | 23 +++++++++++++++++++++
development/ldso/deepbind/main.c | 40 ++++++++++++++++++++++++++++++++++++
4 files changed, 84 insertions(+)
create mode 100644 development/ldso/deepbind/.gitignore
create mode 100644 development/ldso/deepbind/Makefile
create mode 100644 development/ldso/deepbind/lib.c
create mode 100644 development/ldso/deepbind/main.c
(limited to 'development/ldso/deepbind')
diff --git a/development/ldso/deepbind/.gitignore b/development/ldso/deepbind/.gitignore
new file mode 100644
index 0000000..a80e8fd
--- /dev/null
+++ b/development/ldso/deepbind/.gitignore
@@ -0,0 +1,2 @@
+*.so
+main
diff --git a/development/ldso/deepbind/Makefile b/development/ldso/deepbind/Makefile
new file mode 100644
index 0000000..6fc4eb1
--- /dev/null
+++ b/development/ldso/deepbind/Makefile
@@ -0,0 +1,19 @@
+run: build
+ LD_PRELOAD=./libprel.so ./main
+
+debug: build
+ #LD_DEBUG_OUTPUT=ldso
+ LD_DEBUG=scopes,symbols,bindings LD_PRELOAD=./libprel.so ./main
+
+build:
+ gcc -g -o libprel.so lib.c -DNAME=\"prel\" -fPIC -shared
+ gcc -g -o libdeep.so lib.c -DNAME=\"deep\" -fPIC -shared
+ gcc -g -o libnodp.so lib.c -DNAME=\"nodp\" -fPIC -shared
+ gcc -g -o liblink.so lib.c -DNAME=\"link\" -fPIC -shared
+ gcc -g -o main main.c ./liblink.so -ldl
+
+fmt:
+ clang-format -i *.c
+
+clean:
+ $(RM) *.so main
diff --git a/development/ldso/deepbind/lib.c b/development/ldso/deepbind/lib.c
new file mode 100644
index 0000000..e18a4ce
--- /dev/null
+++ b/development/ldso/deepbind/lib.c
@@ -0,0 +1,23 @@
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <stdio.h>
+
+#ifndef NAME
+#define NAME ""
+#endif
+
+void test() {
+ puts(NAME ":test()");
+
+ // Lookup next symbol from the libraries scope, which will search only in the
+ // libraries LOCAL scope, starting from the next object after the current one.
+ (void)dlsym(RTLD_NEXT, "next_lib" NAME);
+
+ // Global lookup from the libraries scope, which will search libraries in the
+ // GLOBAL scope and the libraries LOCAL scope. The order in which the scopes
+ // are searched depends on whether the library was loaded (a) with DEEPBIND or
+ // (b) not. whether this library was loaded with DEEPBIND). In the first case,
+ // the LOCAL scope is searched first, where in the latter, the GLOBAL scope is
+ // searched first.
+ (void)dlsym(RTLD_DEFAULT, "default_lib" NAME);
+}
diff --git a/development/ldso/deepbind/main.c b/development/ldso/deepbind/main.c
new file mode 100644
index 0000000..6d93520
--- /dev/null
+++ b/development/ldso/deepbind/main.c
@@ -0,0 +1,40 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+int main() {
+ puts("-- deep --");
+ // Load library into its own LOCAL scope with DEEPBINDING, meaning that
+ // symbols will first resolve to the library + its dependencies first before
+ // considering global symbols.
+ void* h1 = dlopen("./libdeep.so", RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
+ if (h1) {
+ // Lookup symbol in the libraries LOCAL scope (library + its own
+ // dependencies).
+ void (*test_fn)() = dlsym(h1, "test");
+ test_fn();
+
+ // Lookup non-existing symbol in the libraries LOCAL scope (library + its
+ // own dependencies).
+ (void)dlsym(h1, "libdeep_main");
+ }
+
+ puts("-- nodp --");
+ // Load library into its own LOCAL scope.
+ void* h2 = dlopen("./libnodp.so", RTLD_LOCAL | RTLD_LAZY);
+ if (h2) {
+ // Lookup symbol in the libraries LOCAL scope (library + its own
+ // dependencies).
+ void (*test_fn)() = dlsym(h2, "test");
+ test_fn();
+
+ // Lookup non-existing symbol in the libraries LOCAL scope (library + its
+ // own dependencies).
+ (void)dlsym(h2, "libnodp_main");
+ }
+
+ puts("-- main --");
+ // Lookup non-existing symbol in the GLOBAL scope.
+ (void)dlsym(RTLD_DEFAULT, "default_main");
+
+ return 0;
+}
--
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