From: John Hodge <tpg@ucc.asn.au>
Date: Thu, 4 Oct 2012 13:41:13 +0000 (+0800)
Subject: Syscalls - Changed SysGetMessage to provide a buffer size
X-Git-Tag: rel0.15~700
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=3b864de01887f22d74ec1d564bc99913e5d82be4;p=tpg%2Facess2.git

Syscalls - Changed SysGetMessage to provide a buffer size
---

diff --git a/KernelLand/Kernel/include/threads.h b/KernelLand/Kernel/include/threads.h
index 0362cdb4..6382cf00 100644
--- a/KernelLand/Kernel/include/threads.h
+++ b/KernelLand/Kernel/include/threads.h
@@ -37,6 +37,6 @@ extern char	**Threads_GetCWD(void);
 extern char	**Threads_GetChroot(void);
 
 extern int	Proc_SendMessage(Uint Dest, int Length, void *Data);
-extern int	Proc_GetMessage(Uint *Source, void *Buffer);
+extern int	Proc_GetMessage(Uint *Source, Uint BufSize, void *Buffer);
 
 #endif
diff --git a/KernelLand/Kernel/messages.c b/KernelLand/Kernel/messages.c
index 09c8c14e..c9919780 100644
--- a/KernelLand/Kernel/messages.c
+++ b/KernelLand/Kernel/messages.c
@@ -78,10 +78,11 @@ int Proc_SendMessage(Uint Dest, int Length, void *Data)
  * \fn int Proc_GetMessage(Uint *Source, void *Buffer)
  * \brief Gets a message
  * \param Source	Where to put the source TID
+ * \param BufSize	Size of \a Buffer, only this many bytes will be copied
  * \param Buffer	Buffer to place the message data (set to NULL to just get message length)
  * \return Message length
  */
-int Proc_GetMessage(Uint *Source, void *Buffer)
+int Proc_GetMessage(Uint *Source, Uint BufSize, void *Buffer)
 {
 	 int	ret;
 	void	*tmp;
@@ -113,7 +114,7 @@ int Proc_GetMessage(Uint *Source, void *Buffer)
 	// Get message
 	if(Buffer != GETMSG_IGNORE)
 	{
-		if( !CheckMem( Buffer, cur->Messages->Length ) )
+		if( !CheckMem( Buffer, BufSize ) )
 		{
 			LOG("Invalid buffer");
 			errno = -EINVAL;
@@ -121,8 +122,15 @@ int Proc_GetMessage(Uint *Source, void *Buffer)
 			LEAVE('i', -1);
 			return -1;
 		}
+		if( BufSize < cur->Messages->Length )
+			Log_Notice("Threads", "Buffer of 0x%x passed, but 0x%x long message, truncated",
+				BufSize, cur->Messages->Length);
+		else if( BufSize < cur->Messages->Length )
+			BufSize = cur->Messages->Length;
+		else
+			;	// equal
 		LOG("Copied to buffer");
-		memcpy(Buffer, cur->Messages->Data, cur->Messages->Length);
+		memcpy(Buffer, cur->Messages->Data, BufSize);
 	}
 	ret = cur->Messages->Length;
 	
diff --git a/KernelLand/Kernel/syscalls.c b/KernelLand/Kernel/syscalls.c
index 0348d57a..bfd68bf1 100644
--- a/KernelLand/Kernel/syscalls.c
+++ b/KernelLand/Kernel/syscalls.c
@@ -135,13 +135,10 @@ void SyscallHandler(tSyscallRegs *Regs)
 	// -- Check for messages
 	case SYS_GETMSG:
 		CHECK_NUM_NULLOK( (Uint*)Regs->Arg1, sizeof(Uint) );
-		// NOTE: Can't do range checking as we don't know the size
-		// - Should be done by Proc_GetMessage
-		if( Regs->Arg2 && Regs->Arg2 != -1 && !MM_IsUser(Regs->Arg2) ) {
-			err = -EINVAL;	ret = -1;	break;
-		}
+		if( Regs->Arg3 != -1 )
+			CHECK_NUM_NULLOK((void*)Regs->Arg3, Regs->Arg2);
 		// *Source, *Data
-		ret = Proc_GetMessage((Uint*)Regs->Arg1, (void*)Regs->Arg2);
+		ret = Proc_GetMessage((Uint*)Regs->Arg1, Regs->Arg2, (void*)Regs->Arg3);
 		break;
 	
 	// -- Get the current timestamp
diff --git a/Usermode/Applications/axwin3_src/WM/ipc.c b/Usermode/Applications/axwin3_src/WM/ipc.c
index cbed7fd1..1d4ac33c 100644
--- a/Usermode/Applications/axwin3_src/WM/ipc.c
+++ b/Usermode/Applications/axwin3_src/WM/ipc.c
@@ -112,12 +112,12 @@ void IPC_HandleSelect(fd_set *set)
 		}
 	}
 
-	while(SysGetMessage(NULL, NULL))
+	size_t	len;
+	pid_t	tid;
+	while( (len = SysGetMessage(&tid, 0, NULL)) )
 	{
-		pid_t	tid;
-		 int	len = SysGetMessage(&tid, NULL);
 		char	data[len];
-		SysGetMessage(NULL, data);
+		SysGetMessage(NULL, len, data);
 
 		IPC_Handle(&gIPC_Type_SysMessage, &tid, len, (void*)data);
 //		_SysDebug("IPC_HandleSelect: Message handled");
diff --git a/Usermode/Applications/axwin3_src/libaxwin3.so_src/msg.c b/Usermode/Applications/axwin3_src/libaxwin3.so_src/msg.c
index 2b501672..ac51e277 100644
--- a/Usermode/Applications/axwin3_src/libaxwin3.so_src/msg.c
+++ b/Usermode/Applications/axwin3_src/libaxwin3.so_src/msg.c
@@ -127,7 +127,7 @@ tAxWin_IPCMessage *AxWin3_int_GetIPCMessage(void)
 			pid_t	tid;
 		
 			// Wait for a message to arrive	
-			while( !(len = SysGetMessage(&tid, NULL)) )
+			while( !(len = SysGetMessage(&tid, 0, NULL)) )
 			{
 				_SysWaitEvent(THREAD_EVENT_IPCMSG);
 			}
@@ -140,7 +140,7 @@ tAxWin_IPCMessage *AxWin3_int_GetIPCMessage(void)
 				if( gAxWin3_MessageCallback )
 					gAxWin3_MessageCallback(tid, len);
 				else
-					SysGetMessage(NULL, GETMSG_IGNORE);
+					SysGetMessage(NULL, 0, GETMSG_IGNORE);
 				continue ;
 			}
 			
@@ -148,10 +148,10 @@ tAxWin_IPCMessage *AxWin3_int_GetIPCMessage(void)
 			ret = malloc(len);
 			if(ret == NULL) {
 				_SysDebug("malloc() failed, ignoring message");
-				SysGetMessage(NULL, GETMSG_IGNORE);
+				SysGetMessage(NULL, 0, GETMSG_IGNORE);
 				return NULL;
 			}
-			SysGetMessage(NULL, ret);
+			SysGetMessage(NULL, len, ret);
 			break;
 		}
 		break;
diff --git a/Usermode/Libraries/ld-acess.so_src/include_exp/acess/sys.h b/Usermode/Libraries/ld-acess.so_src/include_exp/acess/sys.h
index 1a954d33..2452972d 100644
--- a/Usermode/Libraries/ld-acess.so_src/include_exp/acess/sys.h
+++ b/Usermode/Libraries/ld-acess.so_src/include_exp/acess/sys.h
@@ -85,7 +85,7 @@ extern int	unlink(const char *pathname);
 
 // --- IPC ---
 extern int	SysSendMessage(pid_t dest, uint length, const void *Data);
-extern int	SysGetMessage(pid_t *src, void *Data);
+extern int	SysGetMessage(pid_t *src, uint buflen, void *Data);
 
 // --- MEMORY ---
 uint64_t	_SysGetPhys(uint vaddr);