Module: xenomai-2.5
Branch: master
Commit: 21c91b544dfb7d6bb8f4157708fc734d47f0bccb
URL:
http://git.xenomai.org/?p=xenomai-2.5.git;a=commit;h=21c91b544dfb7d6bb8f4157708fc734d47f0bccb
Author: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
Date: Mon Mar 8 16:24:09 2010 +0100
posix: fix pthread_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/posix/syscall.c | 25 +++++++++++++++++--------
1 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/ksrc/skins/posix/syscall.c b/ksrc/skins/posix/syscall.c
index 6c3ec3a..2a97a2d 100644
--- a/ksrc/skins/posix/syscall.c
+++ b/ksrc/skins/posix/syscall.c
@@ -1520,7 +1520,7 @@ static int __pthread_cond_wait_prologue(struct pt_regs
*regs)
union __xeno_mutex mx, *umx;
unsigned timed, count;
struct timespec ts;
- int err;
+ int err, perr = 0;
ucnd = (union __xeno_cond *)__xn_reg_arg1(regs);
umx = (union __xeno_mutex *)__xn_reg_arg2(regs);
@@ -1560,7 +1560,10 @@ static int __pthread_cond_wait_prologue(struct pt_regs
*regs)
&mx.shadow_mutex,
&count, timed, XN_INFINITE);
- if (err == 0 || err == ETIMEDOUT) {
+ switch(err) {
+ case 0:
+ case ETIMEDOUT:
+ perr = errno = err;
err = -pse51_cond_timedwait_epilogue(cur, &cnd.shadow_cond,
&mx.shadow_mutex, count);
if (err == 0 &&
@@ -1569,14 +1572,20 @@ static int __pthread_cond_wait_prologue(struct pt_regs
*regs)
&mx.shadow_mutex.lockcnt,
sizeof(umx->shadow_mutex.lockcnt)))
return -EFAULT;
+ break;
+
+ case EINTR:
+ perr = err;
+ errno = 0; /* epilogue should return 0. */
+ break;
}
- if (err == EINTR
- && __xn_safe_copy_to_user((void __user *)__xn_reg_arg3(regs),
- &count, sizeof(count)))
+ if (err == EINTR
+ &&__xn_safe_copy_to_user((void __user *)__xn_reg_arg3(regs),
+ &count, sizeof(count)))
return -EFAULT;
-
- return -err;
+
+ return err == 0 ? -perr : -err;
}
/* pthread_cond_wait_epilogue(cond, mutex, count) */
@@ -1618,7 +1627,7 @@ static int __pthread_cond_wait_epilogue(struct pt_regs
*regs)
sizeof(umx->shadow_mutex.lockcnt)))
return -EFAULT;
- return err;
+ return err == 0 ? -errno : err;
}
static int __pthread_cond_signal(struct pt_regs *regs)
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