From ea14d8a186c342fa8cce02cd0134230dba7e71b3 Mon Sep 17 00:00:00 2001
From: TuxSH <tuxsh@sfr.fr>
Date: Sun, 31 Mar 2019 01:12:22 +0100
Subject: [PATCH] gdb: avoid race conditions

---
 sysmodules/rosalina/include/gdb/server.h      |  4 +++
 sysmodules/rosalina/source/gdb/server.c       | 32 +++++++++++++------
 .../rosalina/source/menus/process_list.c      | 18 +++++++++--
 3 files changed, 42 insertions(+), 12 deletions(-)

diff --git a/sysmodules/rosalina/include/gdb/server.h b/sysmodules/rosalina/include/gdb/server.h
index 77817e0..248eae2 100644
--- a/sysmodules/rosalina/include/gdb/server.h
+++ b/sysmodules/rosalina/include/gdb/server.h
@@ -47,6 +47,10 @@ void GDB_IncrementServerReferenceCount(GDBServer *server);
 void GDB_DecrementServerReferenceCount(GDBServer *server);
 
 void GDB_RunServer(GDBServer *server);
+
+void GDB_LockAllContexts(GDBServer *server);
+void GDB_UnlockAllContexts(GDBServer *server);
+
 GDBContext *GDB_SelectAvailableContext(GDBServer *server, u16 minPort, u16 maxPort);
 
 int GDB_AcceptClient(GDBContext *ctx);
diff --git a/sysmodules/rosalina/source/gdb/server.c b/sysmodules/rosalina/source/gdb/server.c
index 9e894d0..c6075bc 100644
--- a/sysmodules/rosalina/source/gdb/server.c
+++ b/sysmodules/rosalina/source/gdb/server.c
@@ -90,18 +90,35 @@ void GDB_RunServer(GDBServer *server)
     server_run(&server->super);
 }
 
+void GDB_LockAllContexts(GDBServer *server)
+{
+    for (u32 i = 0; i < MAX_DEBUG; i++)
+        RecursiveLock_Lock(&server->ctxs[i].lock);
+}
+
+void GDB_UnlockAllContexts(GDBServer *server)
+{
+    for (u32 i = MAX_DEBUG; i > 0; i--)
+        RecursiveLock_Unlock(&server->ctxs[i - 1].lock);
+}
+
 GDBContext *GDB_SelectAvailableContext(GDBServer *server, u16 minPort, u16 maxPort)
 {
     GDBContext *ctx;
     u16 port;
 
+    GDB_LockAllContexts(server);
+
     // Get a context
     u32 id;
     for(id = 0; id < MAX_DEBUG && (server->ctxs[id].flags & GDB_FLAG_SELECTED); id++);
     if(id < MAX_DEBUG)
         ctx = &server->ctxs[id];
     else
+    {
+        GDB_UnlockAllContexts(server);
         return NULL;
+    }
 
     // Get a port
     for (port = minPort; port < maxPort; port++)
@@ -119,20 +136,17 @@ GDBContext *GDB_SelectAvailableContext(GDBServer *server, u16 minPort, u16 maxPo
 
     if (port >= maxPort)
     {
-        RecursiveLock_Lock(&ctx->lock);
         ctx->flags = ~GDB_FLAG_SELECTED;
-        RecursiveLock_Unlock(&ctx->lock);
-        return NULL;
+        ctx = NULL;
     }
-
     else
     {
-        RecursiveLock_Lock(&ctx->lock);
         ctx->flags |= GDB_FLAG_SELECTED;
         ctx->localPort = port;
-        RecursiveLock_Unlock(&ctx->lock);
-        return ctx;
     }
+
+    GDB_UnlockAllContexts(server);
+    return ctx;
 }
 
 int GDB_AcceptClient(GDBContext *ctx)
@@ -201,6 +215,7 @@ int GDB_CloseClient(GDBContext *ctx)
 
 GDBContext *GDB_GetClient(GDBServer *server, u16 port)
 {
+    GDB_LockAllContexts(server);
     GDBContext *ctx = NULL;
     if (port >= GDB_PORT_BASE && port < GDB_PORT_BASE + MAX_DEBUG)
     {
@@ -216,12 +231,11 @@ GDBContext *GDB_GetClient(GDBServer *server, u16 port)
 
     if (ctx != NULL)
     {
-        RecursiveLock_Lock(&ctx->lock);
         ctx->flags |= GDB_FLAG_USED;
         ctx->state = GDB_STATE_CONNECTED;
-        RecursiveLock_Unlock(&ctx->lock);
     }
 
+    GDB_UnlockAllContexts(server);
     return ctx;
 }
 
diff --git a/sysmodules/rosalina/source/menus/process_list.c b/sysmodules/rosalina/source/menus/process_list.c
index 9c3ae6f..d67f13e 100644
--- a/sysmodules/rosalina/source/menus/process_list.c
+++ b/sysmodules/rosalina/source/menus/process_list.c
@@ -52,9 +52,16 @@ extern GDBServer gdbServer;
 static inline int ProcessListMenu_FormatInfoLine(char *out, const ProcessInfo *info)
 {
     const char *checkbox;
-    u32 id;
-    for(id = 0; id < MAX_DEBUG && (!(gdbServer.ctxs[id].flags & GDB_FLAG_SELECTED) || gdbServer.ctxs[id].pid != info->pid); id++);
-    checkbox = !gdbServer.super.running ? "" : (id < MAX_DEBUG ? "(x) " : "( ) ");
+    u32 id = 0;
+
+    if(gdbServer.super.running)
+    {
+        GDB_LockAllContexts(&gdbServer);
+        for(id = 0; id < MAX_DEBUG && (!(gdbServer.ctxs[id].flags & GDB_FLAG_SELECTED) || gdbServer.ctxs[id].pid != info->pid); id++);
+        checkbox = id < MAX_DEBUG ? "(x) " : "( ) ";
+    }
+    else
+        checkbox = "";
 
     char commentBuf[23 + 1] = { 0 }; // exactly the size of "Remote: 255.255.255.255"
     memset(commentBuf, ' ', 23);
@@ -77,6 +84,8 @@ static inline int ProcessListMenu_FormatInfoLine(char *out, const ProcessInfo *i
         }
     }
 
+    if (gdbServer.super.running)
+        GDB_UnlockAllContexts(&gdbServer);
     return sprintf(out, "%s%-4lu    %-8.8s    %s", checkbox, info->pid, info->name, commentBuf); // Theoritically PIDs are 32-bit ints, but we'll only justify 4 digits
 }
 
@@ -581,6 +590,7 @@ static inline void ProcessListMenu_HandleSelected(const ProcessInfo *info)
         return;
     }
 
+    GDB_LockAllContexts(&gdbServer);
     u32 id;
     for(id = 0; id < MAX_DEBUG && (!(gdbServer.ctxs[id].flags & GDB_FLAG_SELECTED) || gdbServer.ctxs[id].pid != info->pid); id++);
 
@@ -610,6 +620,8 @@ static inline void ProcessListMenu_HandleSelected(const ProcessInfo *info)
         if (ctx != NULL)
             ctx->pid = info->pid;
     }
+
+    GDB_UnlockAllContexts(&gdbServer);
 }
 
 s32 ProcessListMenu_FetchInfo(void)