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Fixing signal records when ktrace'ing under netbsd32 emulation
I recently had to debug something not working for netbsd32 emulation and
found that signals created bogus (64bit) ktrace records.
I came up with the attached patch which seems to work but is a bit ugly
and intrusive. It may not be fully modular and is missing an indirection
from the original ktrpsig -> ktrpsig(), so it is not checking ktrace_on.
I am not sure we can ever get to this code w/o ktrace_on.
I wonder if we should instead of the emulation redirection check
(#ifdef'd properly) for a 32bit process and then hard-coded test against
netbsd32 emulation. No other emulation would ever want to interfere with
the netbsd-specific kte records - or do I miss something?
Martin
P.S.: sendmsg also creates 64bit records, but that is pretty intrusive to
fix too, leaving that for another day.
Index: sys/ktrace.h
===================================================================
RCS file: /cvsroot/src/sys/sys/ktrace.h,v
retrieving revision 1.63
diff -u -p -r1.63 ktrace.h
--- sys/ktrace.h 19 Mar 2016 17:04:12 -0000 1.63
+++ sys/ktrace.h 8 Sep 2016 15:16:01 -0000
@@ -432,6 +432,15 @@ ktrexecfd(int fd, u_int dtype)
ktr_execfd(fd, dtype);
}
+struct ktrace_entry;
+int ktealloc(struct ktrace_entry **, void **, lwp_t *, int, size_t);
+void ktesethdrlen(struct ktrace_entry *, size_t);
+void ktraddentry(lwp_t *, struct ktrace_entry *, int);
+/* Flags for ktraddentry (3rd arg) */
+#define KTA_NOWAIT 0x0000
+#define KTA_WAITOK 0x0001
+#define KTA_LARGE 0x0002
+
#endif /* !_KERNEL */
#endif /* _SYS_KTRACE_H_ */
Index: sys/proc.h
===================================================================
RCS file: /cvsroot/src/sys/sys/proc.h,v
retrieving revision 1.331
diff -u -p -r1.331 proc.h
--- sys/proc.h 10 Jun 2016 23:24:33 -0000 1.331
+++ sys/proc.h 8 Sep 2016 15:16:01 -0000
@@ -192,6 +192,10 @@ struct emul {
void (*e_dtrace_syscall)(uint32_t, register_t,
const struct sysent *, const void *,
const register_t *, int);
+
+ /* Emulation specific support for ktracing signal posts */
+ void (*e_ktrpsig)(int, sig_t, const sigset_t *,
+ const ksiginfo_t *);
};
/*
Index: kern/kern_ktrace.c
===================================================================
RCS file: /cvsroot/src/sys/kern/kern_ktrace.c,v
retrieving revision 1.167
diff -u -p -r1.167 kern_ktrace.c
--- kern/kern_ktrace.c 7 Jul 2016 06:55:43 -0000 1.167
+++ kern/kern_ktrace.c 8 Sep 2016 15:16:01 -0000
@@ -126,8 +126,6 @@ struct ktr_desc {
kcondvar_t ktd_cv;
};
-static int ktealloc(struct ktrace_entry **, void **, lwp_t *, int,
- size_t);
static void ktrwrite(struct ktr_desc *, struct ktrace_entry *);
static int ktrops(lwp_t *, struct proc *, int, int,
struct ktr_desc *);
@@ -142,11 +140,6 @@ static struct ktr_desc *
ktd_lookup(file_t *);
static void ktdrel(struct ktr_desc *);
static void ktdref(struct ktr_desc *);
-static void ktraddentry(lwp_t *, struct ktrace_entry *, int);
-/* Flags for ktraddentry (3rd arg) */
-#define KTA_NOWAIT 0x0000
-#define KTA_WAITOK 0x0001
-#define KTA_LARGE 0x0002
static void ktefree(struct ktrace_entry *);
static void ktd_logerrl(struct ktr_desc *, int);
static void ktrace_thread(void *);
@@ -538,6 +531,12 @@ ktealloc(struct ktrace_entry **ktep, voi
}
void
+ktesethdrlen(struct ktrace_entry *kte, size_t l)
+{
+ kte->kte_kth.ktr_len = l;
+}
+
+void
ktr_syscall(register_t code, const register_t args[], int narg)
{
lwp_t *l = curlwp;
Index: kern/kern_sig.c
===================================================================
RCS file: /cvsroot/src/sys/kern/kern_sig.c,v
retrieving revision 1.329
diff -u -p -r1.329 kern_sig.c
--- kern/kern_sig.c 21 Aug 2016 15:24:17 -0000 1.329
+++ kern/kern_sig.c 8 Sep 2016 15:16:01 -0000
@@ -913,8 +913,14 @@ trapsignal(struct lwp *l, ksiginfo_t *ks
kpsendsig(l, ksi, mask);
mutex_exit(p->p_lock);
if (ktrpoint(KTR_PSIG)) {
- ktrpsig(signo, SIGACTION_PS(ps, signo).sa_handler,
- mask, ksi);
+ if (__predict_false(p->p_emul->e_ktrpsig))
+ p->p_emul->e_ktrpsig(signo,
+ SIGACTION_PS(ps, signo).sa_handler,
+ mask, ksi);
+ else
+ ktrpsig(signo,
+ SIGACTION_PS(ps, signo).sa_handler,
+ mask, ksi);
}
} else {
/* XXX for core dump/debugger */
@@ -1860,7 +1866,11 @@ postsig(int signo)
if (ktrpoint(KTR_PSIG)) {
mutex_exit(p->p_lock);
- ktrpsig(signo, action, returnmask, &ksi);
+ if (__predict_false(p->p_emul->e_ktrpsig))
+ p->p_emul->e_ktrpsig(signo, action,
+ returnmask, &ksi);
+ else
+ ktrpsig(signo, action, returnmask, &ksi);
mutex_enter(p->p_lock);
}
Index: compat/netbsd32/netbsd32.h
===================================================================
RCS file: /cvsroot/src/sys/compat/netbsd32/netbsd32.h,v
retrieving revision 1.109
diff -u -p -r1.109 netbsd32.h
--- compat/netbsd32/netbsd32.h 26 Nov 2015 13:15:34 -0000 1.109
+++ compat/netbsd32/netbsd32.h 8 Sep 2016 15:16:01 -0000
@@ -1105,6 +1105,7 @@ void netbsd32_adjust_limits(struct proc
void netbsd32_si_to_si32(siginfo32_t *, const siginfo_t *);
void netbsd32_ksi32_to_ksi(struct _ksiginfo *si, const struct __ksiginfo32 *si32);
+void netbsd32_ksi_to_ksi32(struct __ksiginfo32 *si32, const struct _ksiginfo *si);
void startlwp32(void *);
Index: compat/netbsd32/netbsd32_netbsd.c
===================================================================
RCS file: /cvsroot/src/sys/compat/netbsd32/netbsd32_netbsd.c,v
retrieving revision 1.200
diff -u -p -r1.200 netbsd32_netbsd.c
--- compat/netbsd32/netbsd32_netbsd.c 13 May 2016 16:54:36 -0000 1.200
+++ compat/netbsd32/netbsd32_netbsd.c 8 Sep 2016 15:16:01 -0000
@@ -71,6 +71,7 @@ __KERNEL_RCSID(0, "$NetBSD: netbsd32_net
#include <sys/dirent.h>
#include <sys/quotactl.h>
#include <sys/kauth.h>
+#include <sys/ktrace.h>
#include <sys/vfs_syscalls.h>
#include <uvm/uvm_extern.h>
@@ -103,6 +104,8 @@ void netbsd32_syscall_intern(struct proc
void syscall(void);
#endif
+void netbsd32_ktrpsig(int, sig_t, const sigset_t *, const ksiginfo_t *);
+
#define LIMITCHECK(a, b) ((a) != RLIM_INFINITY && (a) > (b))
#ifdef COMPAT_16
@@ -162,7 +165,8 @@ struct emul emul_netbsd32 = {
.e_vm_default_addr = netbsd32_vm_default_addr,
.e_usertrap = NULL,
.e_ucsize = sizeof(ucontext32_t),
- .e_startlwp = startlwp32
+ .e_startlwp = startlwp32,
+ .e_ktrpsig = netbsd32_ktrpsig
};
/*
@@ -2890,6 +2894,48 @@ netbsd32__pset_bind(struct lwp *l,
return sys__pset_bind(l, &ua, retval);
}
+struct netbsd32_ktr_psig {
+ int signo;
+ netbsd32_pointer_t action;
+ sigset_t mask;
+ int code;
+ /* and optional siginfo_t */
+};
+
+void
+netbsd32_ktrpsig(int sig, sig_t action, const sigset_t *mask,
+ const ksiginfo_t *ksi)
+{
+ struct ktrace_entry *kte;
+ lwp_t *l = curlwp;
+ struct {
+ struct netbsd32_ktr_psig kp;
+ siginfo32_t si;
+ } *kbuf;
+
+ if (!KTRPOINT(l->l_proc, KTR_PSIG))
+ return;
+
+ if (ktealloc(&kte, (void *)&kbuf, l, KTR_PSIG, sizeof(*kbuf)))
+ return;
+
+ kbuf->kp.signo = (char)sig;
+ NETBSD32PTR32(kbuf->kp.action, action);
+ kbuf->kp.mask = *mask;
+
+ if (ksi) {
+ kbuf->kp.code = KSI_TRAPCODE(ksi);
+ (void)memset(&kbuf->si, 0, sizeof(kbuf->si));
+ netbsd32_ksi_to_ksi32(&kbuf->si._info, &ksi->ksi_info);
+ ktesethdrlen(kte, sizeof(*kbuf));
+ } else {
+ kbuf->kp.code = 0;
+ ktesethdrlen(kte, sizeof(struct netbsd32_ktr_psig));
+ }
+
+ ktraddentry(l, kte, KTA_WAITOK);
+}
+
/*
* MI indirect system call support.
Index: compat/netbsd32/netbsd32_signal.c
===================================================================
RCS file: /cvsroot/src/sys/compat/netbsd32/netbsd32_signal.c,v
retrieving revision 1.39
diff -u -p -r1.39 netbsd32_signal.c
--- compat/netbsd32/netbsd32_signal.c 20 Jun 2015 19:58:40 -0000 1.39
+++ compat/netbsd32/netbsd32_signal.c 8 Sep 2016 15:16:01 -0000
@@ -221,6 +221,46 @@ netbsd32_ksi32_to_ksi(struct _ksiginfo *
}
void
+netbsd32_ksi_to_ksi32(struct __ksiginfo32 *si32, const struct _ksiginfo *si)
+{
+ memset(si32, 0, sizeof (*si32));
+ si32->_signo = si->_signo;
+ si32->_code = si->_code;
+ si32->_errno = si->_errno;
+
+ switch (si->_signo) {
+ case SIGILL:
+ case SIGBUS:
+ case SIGSEGV:
+ case SIGFPE:
+ case SIGTRAP:
+ si32->_reason._fault._addr =
+ NETBSD32PTR32I(si->_reason._fault._addr);
+ si32->_reason._fault._trap = si->_reason._fault._trap;
+ break;
+ case SIGALRM:
+ case SIGVTALRM:
+ case SIGPROF:
+ default: /* see sigqueue() and kill1() */
+ si32->_reason._rt._pid = si->_reason._rt._pid;
+ si32->_reason._rt._uid = si->_reason._rt._uid;
+ si32->_reason._rt._value.sival_int = si->_reason._rt._value.sival_int;
+ break;
+ case SIGCHLD:
+ si32->_reason._child._pid = si->_reason._child._pid;
+ si32->_reason._child._uid = si->_reason._child._uid;
+ si32->_reason._child._utime = si->_reason._child._utime;
+ si32->_reason._child._stime = si->_reason._child._stime;
+ break;
+ case SIGURG:
+ case SIGIO:
+ si32->_reason._poll._band = si->_reason._poll._band;
+ si32->_reason._poll._fd = si->_reason._poll._fd;
+ break;
+ }
+}
+
+void
netbsd32_si_to_si32(siginfo32_t *si32, const siginfo_t *si)
{
memset(si32, 0, sizeof (*si32));
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