From 8c2bc394bceb9ba569315eaa751a8fbaa9fe7b77 Mon Sep 17 00:00:00 2001
From: lazymio <mio@lazym.io>
Date: Tue, 16 Nov 2021 21:18:27 +0100
Subject: [PATCH] No need to save jmp_buf and uc in contexts

This reverts #1335 in fact
---
 include/uc_priv.h | 14 +++++---------
 uc.c              | 33 +++------------------------------
 2 files changed, 8 insertions(+), 39 deletions(-)

diff --git a/include/uc_priv.h b/include/uc_priv.h
index f38531ff..c9a11172 100644
--- a/include/uc_priv.h
+++ b/include/uc_priv.h
@@ -341,24 +341,20 @@ struct uc_struct {
                       // default)
     bool first_tb; // is this the first Translation-Block ever generated since
                    // uc_emu_start()?
-    struct list saved_contexts; // The contexts saved by this uc_struct.
-    bool no_exit_request;       // Disable check_exit_request temporarily. A
+    bool no_exit_request; // Disable check_exit_request temporarily. A
                           // workaround to treat the IT block as a whole block.
-    bool init_done; // Whether the initialization is done.
+    bool init_done;       // Whether the initialization is done.
 
     sigjmp_buf jmp_bufs[UC_MAX_NESTED_LEVEL]; // To support nested uc_emu_start
     int nested_level;                         // Current nested_level
 };
 
 // Metadata stub for the variable-size cpu context used with uc_context_*()
-// We also save cpu->jmp_env, so emulation can be reentrant
 struct uc_context {
     size_t context_size; // size of the real internal context structure
-    size_t jmp_env_size; // size of cpu->jmp_env
-    uc_mode mode;        // the mode of this context (uc may be free-ed already)
-    uc_arch arch;        // the arch of this context (uc may be free-ed already)
-    struct uc_struct *uc; // the uc_struct which creates this context
-    char data[0];         // context + cpu->jmp_env
+    uc_mode mode;        // the mode of this context
+    uc_arch arch;        // the arch of this context
+    char data[0];        // context
 };
 
 // check if this address is mapped in (via uc_mem_map())
diff --git a/uc.c b/uc.c
index 69e73f23..06f9823b 100644
--- a/uc.c
+++ b/uc.c
@@ -431,16 +431,6 @@ uc_err uc_close(uc_engine *uc)
 
     free(uc->mapped_blocks);
 
-    // free the saved contexts list and notify them that uc has been closed.
-    cur = uc->saved_contexts.head;
-    while (cur != NULL) {
-        struct list_item *next = cur->next;
-        struct uc_context *context = (struct uc_context *)cur->data;
-        context->uc = NULL;
-        cur = next;
-    }
-    list_clear(&uc->saved_contexts);
-
     g_tree_destroy(uc->exits);
 
     // finally, free uc itself.
@@ -1690,16 +1680,10 @@ uc_err uc_context_alloc(uc_engine *uc, uc_context **context)
 
     *_context = g_malloc(size);
     if (*_context) {
-        (*_context)->jmp_env_size = sizeof(*uc->cpu->jmp_env);
         (*_context)->context_size = uc->cpu_context_size;
         (*_context)->arch = uc->arch;
         (*_context)->mode = uc->mode;
-        (*_context)->uc = uc;
-        if (list_insert(&uc->saved_contexts, *_context)) {
-            return UC_ERR_OK;
-        } else {
-            return UC_ERR_NOMEM;
-        }
+        return UC_ERR_OK;
     } else {
         return UC_ERR_NOMEM;
     }
@@ -1717,8 +1701,7 @@ size_t uc_context_size(uc_engine *uc)
 {
     UC_INIT(uc);
     // return the total size of struct uc_context
-    return sizeof(uc_context) + uc->cpu_context_size +
-           sizeof(*uc->cpu->jmp_env);
+    return sizeof(uc_context) + uc->cpu_context_size;
 }
 
 UNICORN_EXPORT
@@ -1727,8 +1710,6 @@ uc_err uc_context_save(uc_engine *uc, uc_context *context)
     UC_INIT(uc);
 
     memcpy(context->data, uc->cpu->env_ptr, context->context_size);
-    memcpy(context->data + context->context_size, uc->cpu->jmp_env,
-           context->jmp_env_size);
 
     return UC_ERR_OK;
 }
@@ -1900,10 +1881,6 @@ uc_err uc_context_restore(uc_engine *uc, uc_context *context)
     UC_INIT(uc);
 
     memcpy(uc->cpu->env_ptr, context->data, context->context_size);
-    if (list_exists(&uc->saved_contexts, context)) {
-        memcpy(uc->cpu->jmp_env, context->data + context->context_size,
-               context->jmp_env_size);
-    }
 
     return UC_ERR_OK;
 }
@@ -1911,11 +1888,7 @@ uc_err uc_context_restore(uc_engine *uc, uc_context *context)
 UNICORN_EXPORT
 uc_err uc_context_free(uc_context *context)
 {
-    uc_engine *uc = context->uc;
-    // if uc is NULL, it means that uc_engine has been free-ed.
-    if (uc) {
-        list_remove(&uc->saved_contexts, context);
-    }
+
     return uc_free(context);
 }