Author: kib
Date: Thu Apr 12 10:48:43 2012
New Revision: 234172
URL: http://svn.freebsd.org/changeset/base/234172
Log:
Add thread-private flag to indicate that error value is already placed
in td_errno. Flag is supposed to be used by syscalls returning
EJUSTRETURN because errno was already placed into the usermode frame
by a call to set_syscall_retval(9). Both ktrace and dtrace get errno
value from td_errno if the flag is set.
Use the flag to fix sigsuspend(2) error return ktrace records.
Requested by: bde
MFC after: 1 week
Modified:
head/sys/kern/kern_sig.c
head/sys/kern/subr_syscall.c
head/sys/sys/proc.h
Modified: head/sys/kern/kern_sig.c
==============================================================================
--- head/sys/kern/kern_sig.c Thu Apr 12 10:32:34 2012 (r234171)
+++ head/sys/kern/kern_sig.c Thu Apr 12 10:48:43 2012 (r234172)
@@ -1465,6 +1465,8 @@ kern_sigsuspend(struct thread *td, sigse
mtx_unlock(&p->p_sigacts->ps_mtx);
}
PROC_UNLOCK(p);
+ td->td_errno = EINTR;
+ td->td_pflags |= TDP_NERRNO;
return (EJUSTRETURN);
}
Modified: head/sys/kern/subr_syscall.c
==============================================================================
--- head/sys/kern/subr_syscall.c Thu Apr 12 10:32:34 2012
(r234171)
+++ head/sys/kern/subr_syscall.c Thu Apr 12 10:48:43 2012
(r234172)
@@ -136,7 +136,8 @@ syscallenter(struct thread *td, struct s
AUDIT_SYSCALL_EXIT(error, td);
/* Save the latest error return value. */
- td->td_errno = error;
+ if ((td->td_pflags & TDP_NERRNO) == 0)
+ td->td_errno = error;
#ifdef KDTRACE_HOOKS
/*
@@ -191,9 +192,12 @@ syscallret(struct thread *td, int error,
syscallname(p, sa->code), td, td->td_proc->p_pid, td->td_name);
#ifdef KTRACE
- if (KTRPOINT(td, KTR_SYSRET))
- ktrsysret(sa->code, error, td->td_retval[0]);
+ if (KTRPOINT(td, KTR_SYSRET)) {
+ ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ?
+ error : td->td_errno, td->td_retval[0]);
+ }
#endif
+ td->td_pflags &= ~TDP_NERRNO;
if (p->p_flag & P_TRACED) {
traced = 1;
Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h Thu Apr 12 10:32:34 2012 (r234171)
+++ head/sys/sys/proc.h Thu Apr 12 10:48:43 2012 (r234172)
@@ -418,6 +418,7 @@ do {
\
#define TDP_AUDITREC 0x01000000 /* Audit record pending on thread */
#define TDP_RFPPWAIT 0x02000000 /* Handle RFPPWAIT on syscall exit */
#define TDP_RESETSPUR 0x04000000 /* Reset spurious page fault
history. */
+#define TDP_NERRNO 0x08000000 /* Last errno is already in td_errno
*/
/*
* Reasons that the current thread can not be run yet.
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