From 0c15afd9d0d87d1cff59dc2adb0afd5e1b6bdf72 Mon Sep 17 00:00:00 2001
From: YAMAMOTO Takashi <imuwoto@gmail.com>
Date: Mon, 5 Aug 2024 20:35:25 +0900
Subject: [PATCH] libdyld: use separate mem contexts for each objects

---
 libdyld/dyld.c      | 15 +++++++++++----
 libdyld/dyld_impl.h |  4 ++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/libdyld/dyld.c b/libdyld/dyld.c
index 8483cebe..72cce966 100644
--- a/libdyld/dyld.c
+++ b/libdyld/dyld.c
@@ -652,7 +652,8 @@ dyld_object_destroy(struct dyld_object *obj)
         struct dyld *d = obj->dyld;
         struct mem_context *mctx = d->mctx;
         if (obj->local_import_obj != NULL) {
-                import_object_destroy(mctx, obj->local_import_obj);
+                import_object_destroy(&obj->instance_mctx,
+                                      obj->local_import_obj);
         }
         mem_free(mctx, obj->gots, obj->ngots * sizeof(*obj->gots));
         mem_free(mctx, obj->plts, obj->nplts * sizeof(*obj->plts));
@@ -660,11 +661,13 @@ dyld_object_destroy(struct dyld_object *obj)
                 instance_destroy(obj->instance);
         }
         if (obj->module != NULL) {
-                module_destroy(mctx, obj->module);
+                module_destroy(&obj->module_mctx, obj->module);
         }
         if (obj->bin != NULL) {
                 unmap_file((void *)obj->bin, obj->binsz);
         }
+        mem_context_clear(&obj->module_mctx);
+        mem_context_clear(&obj->instance_mctx);
         mem_free(mctx, obj, sizeof(*obj));
 }
 
@@ -790,6 +793,10 @@ dyld_load_object_from_file(struct dyld *d, const struct name *name,
                 ret = ENOMEM;
                 goto fail;
         }
+        mem_context_init(&obj->module_mctx);
+        obj->module_mctx.parent = d->mctx;
+        mem_context_init(&obj->instance_mctx);
+        obj->instance_mctx.parent = d->mctx;
         obj->dyld = d;
         obj->name = name;
         ret = map_file(filename, (void *)&obj->bin, &obj->binsz);
@@ -797,7 +804,7 @@ dyld_load_object_from_file(struct dyld *d, const struct name *name,
                 goto fail;
         }
         struct load_context lctx;
-        load_context_init(&lctx, d->mctx);
+        load_context_init(&lctx, &obj->module_mctx);
         ret = module_create(&obj->module, obj->bin, obj->bin + obj->binsz,
                             &lctx);
         if (ret != 0) {
@@ -862,7 +869,7 @@ dyld_load_object_from_file(struct dyld *d, const struct name *name,
         obj->local_import_obj->next = d->shared_import_obj;
         struct report report;
         report_init(&report);
-        ret = instance_create(d->mctx, obj->module, &obj->instance,
+        ret = instance_create(&obj->instance_mctx, obj->module, &obj->instance,
                               obj->local_import_obj, &report);
         if (ret != 0) {
                 xlog_error("instance_create failed with %d: %s", ret,
diff --git a/libdyld/dyld_impl.h b/libdyld/dyld_impl.h
index 75f428d8..2ea5afe6 100644
--- a/libdyld/dyld_impl.h
+++ b/libdyld/dyld_impl.h
@@ -1,6 +1,7 @@
 #include <stdbool.h>
 
 #include "list.h"
+#include "mem.h"
 #include "type.h"
 
 struct dyld;
@@ -40,6 +41,9 @@ struct dyld_object {
         struct module *module;
         struct instance *instance;
 
+        struct mem_context module_mctx;
+        struct mem_context instance_mctx;
+
         struct dyld *dyld;
         LIST_ENTRY(struct dyld_object) q;