Module: xenomai-2.5
Branch: master
Commit: d656c6dcc413b02997b5bbb1ad368b33672ed8ff
URL:
http://git.xenomai.org/?p=xenomai-2.5.git;a=commit;h=d656c6dcc413b02997b5bbb1ad368b33672ed8ff
Author: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
Date: Mon Mar 8 21:01:38 2010 +0100
native: fix rt_cond_*wait return value overwriting
This fix uses errno to remember, at the time of the epilogue, the value
returned by the prologue. It will not work if cond_*wait are interrupted
by signals, and the signal handler uses a system call which overrides errno.
---
ksrc/skins/native/syscall.c | 32 +++++++++++++++++++++++++-------
1 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/ksrc/skins/native/syscall.c b/ksrc/skins/native/syscall.c
index 40e5cfd..320eaaf 100644
--- a/ksrc/skins/native/syscall.c
+++ b/ksrc/skins/native/syscall.c
@@ -41,6 +41,8 @@
#include <native/buffer.h>
#include <native/misc.h>
+#define rt_task_errno (*xnthread_get_errno_location(xnpod_current_thread()))
+
/*
* This file implements the Xenomai syscall wrappers. All skin
* services (re-)check the object descriptor they are passed; so there
@@ -1837,11 +1839,11 @@ static int __rt_cond_wait_prologue(struct pt_regs *regs)
{
RT_COND_PLACEHOLDER cph, mph;
xntmode_t timeout_mode;
+ int err, perr = 0;
unsigned lockcnt;
RT_MUTEX *mutex;
RT_COND *cond;
RTIME timeout;
- int err;
if (__xn_safe_copy_from_user(&cph, (void __user *)__xn_reg_arg1(regs),
sizeof(cph)))
@@ -1869,15 +1871,27 @@ static int __rt_cond_wait_prologue(struct pt_regs *regs)
err = rt_cond_wait_prologue(cond, mutex, &lockcnt, timeout_mode,
timeout);
- if (err == 0 || err == -ETIMEDOUT)
+ switch(err) {
+ case 0:
+ case -ETIMEDOUT:
+ case -EIDRM:
+ perr = rt_task_errno = err;
err = rt_cond_wait_epilogue(mutex, lockcnt);
-
- if (err == -EINTR && __xn_reg_arg3(regs)
+ break;
+
+ case -EINTR:
+ perr = err;
+ rt_task_errno = 0; /* epilogue should return 0. */
+ break;
+ }
+
+ if (err == -EINTR
+ && __xn_reg_arg3(regs)
&& __xn_safe_copy_to_user((void __user *)__xn_reg_arg3(regs),
&lockcnt, sizeof(lockcnt)))
return -EFAULT;
- return err;
+ return err == 0 ? perr : err;
}
/*
@@ -1889,6 +1903,7 @@ static int __rt_cond_wait_epilogue(struct pt_regs *regs)
RT_COND_PLACEHOLDER mph;
unsigned lockcnt;
RT_MUTEX *mutex;
+ int err;
if (__xn_safe_copy_from_user(&mph, (void __user *)__xn_reg_arg1(regs),
sizeof(mph)))
@@ -1901,7 +1916,9 @@ static int __rt_cond_wait_epilogue(struct pt_regs *regs)
lockcnt = __xn_reg_arg2(regs);
- return rt_cond_wait_epilogue(mutex, lockcnt);
+ err = rt_cond_wait_epilogue(mutex, lockcnt);
+
+ return err == 0 ? rt_task_errno : err;
}
/*
@@ -4090,7 +4107,8 @@ static xnsysent_t __systab[] = {
[__native_cond_bind] = {&__rt_cond_bind, __xn_exec_conforming},
[__native_cond_delete] = {&__rt_cond_delete, __xn_exec_any},
[__native_cond_wait_prologue] =
- {&__rt_cond_wait_prologue, __xn_exec_primary},
+ {&__rt_cond_wait_prologue,
+ __xn_exec_primary | __xn_exec_norestart},
[__native_cond_wait_epilogue] =
{&__rt_cond_wait_epilogue, __xn_exec_primary},
[__native_cond_signal] = {&__rt_cond_signal, __xn_exec_any},
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