svn commit: r350012 - in head/sys: kern sys
John Baldwin
jhb at FreeBSD.org
Mon Jul 15 21:16:02 UTC 2019
Author: jhb
Date: Mon Jul 15 21:16:01 2019
New Revision: 350012
URL: https://svnweb.freebsd.org/changeset/base/350012
Log:
Always set td_errno to the error value of a system call.
Early errors prior to a system call did not set td_errno. This commit
sets td_errno for all errors during syscallenter(). As a result,
syscallret() can now always use td_errno without checking TDP_NERRNO.
Reviewed by: kib
MFC after: 1 month
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D20898
Modified:
head/sys/kern/kern_thread.c
head/sys/kern/subr_syscall.c
head/sys/sys/proc.h
Modified: head/sys/kern/kern_thread.c
==============================================================================
--- head/sys/kern/kern_thread.c Mon Jul 15 20:45:01 2019 (r350011)
+++ head/sys/kern/kern_thread.c Mon Jul 15 21:16:01 2019 (r350012)
@@ -84,7 +84,7 @@ _Static_assert(offsetof(struct thread, td_pflags) == 0
"struct thread KBI td_pflags");
_Static_assert(offsetof(struct thread, td_frame) == 0x478,
"struct thread KBI td_frame");
-_Static_assert(offsetof(struct thread, td_emuldata) == 0x548,
+_Static_assert(offsetof(struct thread, td_emuldata) == 0x540,
"struct thread KBI td_emuldata");
_Static_assert(offsetof(struct proc, p_flag) == 0xb0,
"struct proc KBI p_flag");
@@ -102,7 +102,7 @@ _Static_assert(offsetof(struct thread, td_flags) == 0x
"struct thread KBI td_flags");
_Static_assert(offsetof(struct thread, td_pflags) == 0xa0,
"struct thread KBI td_pflags");
-_Static_assert(offsetof(struct thread, td_frame) == 0x2ec,
+_Static_assert(offsetof(struct thread, td_frame) == 0x2f0,
"struct thread KBI td_frame");
_Static_assert(offsetof(struct thread, td_emuldata) == 0x338,
"struct thread KBI td_emuldata");
Modified: head/sys/kern/subr_syscall.c
==============================================================================
--- head/sys/kern/subr_syscall.c Mon Jul 15 20:45:01 2019 (r350011)
+++ head/sys/kern/subr_syscall.c Mon Jul 15 21:16:01 2019 (r350012)
@@ -85,8 +85,10 @@ syscallenter(struct thread *td)
(uintptr_t)td, "pid:%d", td->td_proc->p_pid, "arg0:%p", sa->args[0],
"arg1:%p", sa->args[1], "arg2:%p", sa->args[2]);
- if (error != 0)
+ if (error != 0) {
+ td->td_errno = error;
goto retval;
+ }
STOPEVENT(p, S_SCE, sa->narg);
if ((p->p_flag & P_TRACED) != 0) {
@@ -105,8 +107,10 @@ syscallenter(struct thread *td)
if (KTRPOINT(td, KTR_SYSCALL))
ktrsyscall(sa->code, sa->narg, sa->args);
#endif
- if (error != 0)
+ if (error != 0) {
+ td->td_errno = error;
goto retval;
+ }
}
#ifdef CAPABILITY_MODE
@@ -116,14 +120,16 @@ syscallenter(struct thread *td)
*/
if (IN_CAPABILITY_MODE(td) &&
!(sa->callp->sy_flags & SYF_CAPENABLED)) {
- error = ECAPMODE;
+ td->td_errno = error = ECAPMODE;
goto retval;
}
#endif
error = syscall_thread_enter(td, sa->callp);
- if (error != 0)
+ if (error != 0) {
+ td->td_errno = error;
goto retval;
+ }
#ifdef KDTRACE_HOOKS
/* Give the syscall:::entry DTrace probe a chance to fire. */
@@ -131,6 +137,9 @@ syscallenter(struct thread *td)
(*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0);
#endif
+ /* Let system calls set td_errno directly. */
+ td->td_pflags &= ~TDP_NERRNO;
+
AUDIT_SYSCALL_ENTER(sa->code, td);
error = (sa->callp->sy_call)(td, sa->args);
AUDIT_SYSCALL_EXIT(error, td);
@@ -162,12 +171,12 @@ syscallenter(struct thread *td)
}
static inline void
-syscallret(struct thread *td, int error)
+syscallret(struct thread *td, int error __unused)
{
struct proc *p;
struct syscall_args *sa;
ksiginfo_t ksi;
- int traced, error1;
+ int traced;
KASSERT((td->td_pflags & TDP_FORKING) == 0,
("fork() did not clear TDP_FORKING upon completion"));
@@ -176,12 +185,10 @@ syscallret(struct thread *td, int error)
sa = &td->td_sa;
if ((trap_enotcap || (p->p_flag2 & P2_TRAPCAP) != 0) &&
IN_CAPABILITY_MODE(td)) {
- error1 = (td->td_pflags & TDP_NERRNO) == 0 ? error :
- td->td_errno;
- if (error1 == ENOTCAPABLE || error1 == ECAPMODE) {
+ if (td->td_errno == ENOTCAPABLE || td->td_errno == ECAPMODE) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGTRAP;
- ksi.ksi_errno = error1;
+ ksi.ksi_errno = td->td_errno;
ksi.ksi_code = TRAP_CAP;
trapsignal(td, &ksi);
}
@@ -194,11 +201,9 @@ syscallret(struct thread *td, int error)
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSRET)) {
- ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ?
- error : td->td_errno, td->td_retval[0]);
+ ktrsysret(sa->code, 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 Mon Jul 15 20:45:01 2019 (r350011)
+++ head/sys/sys/proc.h Mon Jul 15 21:16:01 2019 (r350012)
@@ -303,6 +303,7 @@ struct thread {
void *td_su; /* (k) FFS SU private */
sbintime_t td_sleeptimo; /* (t) Sleep timeout. */
int td_rtcgen; /* (s) rtc_generation of abs. sleep */
+ int td_errno; /* (k) Error from last syscall. */
size_t td_vslock_sz; /* (k) amount of vslock-ed space */
struct kcov_info *td_kcov_info; /* (*) Kernel code coverage data */
#define td_endzero td_sigmask
@@ -353,8 +354,6 @@ struct thread {
struct kaudit_record *td_ar; /* (k) Active audit record, if any. */
struct lpohead td_lprof[2]; /* (a) lock profiling objects. */
struct kdtrace_thread *td_dtrace; /* (*) DTrace-specific data. */
- int td_errno; /* Error returned by last syscall. */
- /* LP64 hole */
struct vnet *td_vnet; /* (k) Effective vnet. */
const char *td_vnet_lpush; /* (k) Debugging vnet push / pop. */
struct trapframe *td_intr_frame;/* (k) Frame of the current irq */
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