From f10c38f7e5c01721ae8b0945e5e6927321b94528 Mon Sep 17 00:00:00 2001
From: Tom Hughes <tom@compton.nu>
Date: Thu, 29 Jul 2004 22:40:07 +0000
Subject: [PATCH] Modify the ipc system call so that only those calls which may
 block are treated as blocking.

This fixes bug #86000 because shmat is no longer treated as blocking
and it is therefore no longer possible for two threads to try and use
the same address for the shared memory segment.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@2536
---
 coregrind/vg_syscalls.c  | 10 +++++++++-
 include/vg_kerneliface.h |  8 ++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/coregrind/vg_syscalls.c b/coregrind/vg_syscalls.c
index d6f03cffa5..e1532260f6 100644
--- a/coregrind/vg_syscalls.c
+++ b/coregrind/vg_syscalls.c
@@ -2553,6 +2553,7 @@ PRE(ipc)
    case 1: /* IPCOP_semop */
       SYSCALL_TRACK( pre_mem_read, tid, "semop(sops)", arg5, 
 		     arg3 * sizeof(struct sembuf) );
+      tst->sys_flags |= MayBlock;
       break;
    case 2: /* IPCOP_semget */
    case 3: /* IPCOP_semctl */
@@ -2563,6 +2564,7 @@ PRE(ipc)
       if (arg6 != (UInt)NULL)
          SYSCALL_TRACK( pre_mem_read, tid, "semtimedop(timeout)", arg5, 
                         sizeof(struct timespec) );
+      tst->sys_flags |= MayBlock;
       break;
    case 11: /* IPCOP_msgsnd */
    {
@@ -2573,6 +2575,9 @@ PRE(ipc)
 		     (UInt)&msgp->mtype, sizeof(msgp->mtype) );
       SYSCALL_TRACK( pre_mem_read, tid, "msgsnd(msgp->mtext)", 
 		     (UInt)msgp->mtext, msgsz );
+
+      if ((arg4 & VKI_IPC_NOWAIT) == 0)
+         tst->sys_flags |= MayBlock;
       break;
    }
    case 12: /* IPCOP_msgrcv */
@@ -2588,6 +2593,9 @@ PRE(ipc)
 		     (UInt)&msgp->mtype, sizeof(msgp->mtype) );
       SYSCALL_TRACK( pre_mem_write, tid, "msgrcv(msgp->mtext)", 
 		     (UInt)msgp->mtext, msgsz );
+
+      if ((arg4 & VKI_IPC_NOWAIT) == 0)
+         tst->sys_flags |= MayBlock;
       break;
    }
    case 13: /* IPCOP_msgget */
@@ -5684,7 +5692,7 @@ static const struct sys_info sys_info[] = {
    SYSBA(gettimeofday,		0),
    SYSB_(getuid,		0),
    SYSB_(getuid32,		0),
-   SYSBA(ipc,			MayBlock),
+   SYSBA(ipc,			0),
    SYSBA(ioctl,			MayBlock),
    SYSBA(kill,			0),
    SYSB_(link,			MayBlock),
diff --git a/include/vg_kerneliface.h b/include/vg_kerneliface.h
index 79580fb588..c4b02202ee 100644
--- a/include/vg_kerneliface.h
+++ b/include/vg_kerneliface.h
@@ -769,6 +769,14 @@ struct vki_statfs64 {
 #define VKI_FUTEX_FD      2
 #define VKI_FUTEX_REQUEUE 3
 
+/*
+ * linux/ipc.h
+ */
+
+#define VKI_IPC_CREAT  00001000   /* create if key is nonexistent */
+#define VKI_IPC_EXCL   00002000   /* fail if key exists */
+#define VKI_IPC_NOWAIT 00004000   /* return error on wait */
+
 /* 
  * linux/elfcore.h
  */
-- 
2.47.2