Date: Thu, 1 Jul 2010 16:42:17 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: arch@freebsd.org Subject: Access to siginfo for the signal from debugger Message-ID: <20100701134217.GM13238@deviant.kiev.zoral.com.ua>
next in thread | raw e-mail | index | archive | help
--w9Xseu/t+w8u+RRD
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
Hi,
below is the patch that provides the debugger with access to siginfo
of the signal that stopped the debuggee. This allows to see a lot more
details for the cause of the process stop. E.g. you can see a fault
address if process get SIGSEGV or SIGBUS, you can distinguish between
breakpoint-generated SIGTRAP and non-breakpoint, whether the signal
was send due to external event etc.
The change to struct ptrace_lwpinfo is backward-compatible in the sense
that programs that were compiled with old definition for the struct will
work on new kernels.
I tested the change on i386 and amd64, both native and ia32 mode.
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/f=
reebsd32_misc.c
index f0fde2b..1d60ed4 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -2208,7 +2208,7 @@ freebsd32_thr_suspend(struct thread *td, struct freeb=
sd32_thr_suspend_args *uap)
}
=20
void
-siginfo_to_siginfo32(siginfo_t *src, struct siginfo32 *dst)
+siginfo_to_siginfo32(const siginfo_t *src, struct siginfo32 *dst)
{
bzero(dst, sizeof(*dst));
dst->si_signo =3D src->si_signo;
diff --git a/sys/compat/freebsd32/freebsd32_signal.h b/sys/compat/freebsd32=
/freebsd32_signal.h
index ba0922a..2669581 100644
--- a/sys/compat/freebsd32/freebsd32_signal.h
+++ b/sys/compat/freebsd32/freebsd32_signal.h
@@ -96,6 +96,6 @@ struct sigevent32 {
} _sigev_un;
};
=20
-void siginfo_to_siginfo32(siginfo_t *src, struct siginfo32 *dst);
+void siginfo_to_siginfo32(const siginfo_t *src, struct siginfo32 *dst);
=20
#endif /* !_COMPAT_FREEBSD32_SIGNAL_H_ */
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 04c2ba7..af3c7da 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -2522,7 +2522,6 @@ issignal(struct thread *td, int stop_allowed)
struct sigacts *ps;
struct sigqueue *queue;
sigset_t sigpending;
- ksiginfo_t ksi;
int sig, prop, newsig;
=20
p =3D td->td_proc;
@@ -2565,10 +2564,10 @@ issignal(struct thread *td, int stop_allowed)
* be thrown away.
*/
queue =3D &td->td_sigqueue;
- ksi.ksi_signo =3D 0;
- if (sigqueue_get(queue, sig, &ksi) =3D=3D 0) {
+ td->td_dbgksi.ksi_signo =3D 0;
+ if (sigqueue_get(queue, sig, &td->td_dbgksi) =3D=3D 0) {
queue =3D &p->p_sigqueue;
- sigqueue_get(queue, sig, &ksi);
+ sigqueue_get(queue, sig, &td->td_dbgksi);
}
=20
mtx_unlock(&ps->ps_mtx);
@@ -2595,13 +2594,13 @@ issignal(struct thread *td, int stop_allowed)
continue;
signotify(td);
} else {
- if (ksi.ksi_signo !=3D 0) {
- ksi.ksi_flags |=3D KSI_HEAD;
+ if (td->td_dbgksi.ksi_signo !=3D 0) {
+ td->td_dbgksi.ksi_flags |=3D KSI_HEAD;
if (sigqueue_add(&td->td_sigqueue, sig,
- &ksi) !=3D 0)
- ksi.ksi_signo =3D 0;
+ &td->td_dbgksi) !=3D 0)
+ td->td_dbgksi.ksi_signo =3D 0;
}
- if (ksi.ksi_signo =3D=3D 0)
+ if (td->td_dbgksi.ksi_signo =3D=3D 0)
sigqueue_add(&td->td_sigqueue, sig,
NULL);
}
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index 40c861b..525c0e2 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -64,6 +64,7 @@ __FBSDID("$FreeBSD$");
=20
#ifdef COMPAT_FREEBSD32
#include <sys/procfs.h>
+#include <compat/freebsd32/freebsd32_signal.h>
=20
struct ptrace_io_desc32 {
int piod_op;
@@ -85,6 +86,15 @@ struct ptrace_vm_entry32 {
uint32_t pve_path;
};
=20
+struct ptrace_lwpinfo32 {
+ lwpid_t pl_lwpid; /* LWP described. */
+ int pl_event; /* Event that stopped the LWP. */
+ int pl_flags; /* LWP flags. */
+ sigset_t pl_sigmask; /* LWP signal mask */
+ sigset_t pl_siglist; /* LWP pending signal */
+ struct siginfo32 pl_siginfo; /* siginfo for signal */
+};
+
#endif
=20
/*
@@ -498,6 +508,19 @@ ptrace_vm_entry32(struct thread *td, struct proc *p,
pve32->pve_pathlen =3D pve.pve_pathlen;
return (error);
}
+
+static void
+ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
+ struct ptrace_lwpinfo32 *pl32)
+{
+
+ pl32->pl_lwpid =3D pl->pl_lwpid;
+ pl32->pl_event =3D pl->pl_event;
+ pl32->pl_flags =3D pl->pl_flags;
+ pl32->pl_sigmask =3D pl->pl_sigmask;
+ pl32->pl_siglist =3D pl->pl_siglist;
+ siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
+}
#endif /* COMPAT_FREEBSD32 */
=20
/*
@@ -552,6 +575,7 @@ ptrace(struct thread *td, struct ptrace_args *uap)
struct fpreg32 fpreg32;
struct reg32 reg32;
struct ptrace_io_desc32 piod32;
+ struct ptrace_lwpinfo32 pl32;
struct ptrace_vm_entry32 pve32;
#endif
} r;
@@ -662,6 +686,8 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void=
*addr, int data)
#ifdef COMPAT_FREEBSD32
int wrap32 =3D 0, safe =3D 0;
struct ptrace_io_desc32 *piod32 =3D NULL;
+ struct ptrace_lwpinfo32 *pl32 =3D NULL;
+ struct ptrace_lwpinfo plr;
#endif
=20
curp =3D td->td_proc;
@@ -1103,15 +1129,44 @@ kern_ptrace(struct thread *td, int req, pid_t pid, =
void *addr, int data)
break;
=20
case PT_LWPINFO:
- if (data <=3D 0 || data > sizeof(*pl)) {
+ if (data <=3D 0 ||
+#ifdef COMPAT_FREEBSD32
+ (!wrap32 && data > sizeof(*pl)) ||
+ (wrap32 && data > sizeof(*pl32))) {
+#else
+ data > sizeof(*pl)) {
+#endif
error =3D EINVAL;
break;
}
+#ifdef COMPAT_FREEBSD32
+ if (wrap32) {
+ pl =3D &plr;
+ pl32 =3D addr;
+ } else
+#endif
pl =3D addr;
pl->pl_lwpid =3D td2->td_tid;
- if (td2->td_dbgflags & TDB_XSIG)
- pl->pl_event =3D PL_EVENT_SIGNAL;
pl->pl_flags =3D 0;
+ if (td2->td_dbgflags & TDB_XSIG) {
+ pl->pl_event =3D PL_EVENT_SIGNAL;
+ if (td2->td_dbgksi.ksi_signo !=3D 0 &&
+#ifdef COMPAT_FREEBSD32
+ ((!wrap32 && data >=3D offsetof(struct ptrace_lwpinfo,
+ pl_siginfo) + sizeof(pl->pl_siginfo)) ||
+ (wrap32 && data >=3D offsetof(struct ptrace_lwpinfo32,
+ pl_siginfo) + sizeof(struct siginfo32)))
+#else
+ data >=3D offsetof(struct ptrace_lwpinfo, pl_siginfo)
+ + sizeof(pl->pl_siginfo)
+#endif
+ ){
+ pl->pl_flags |=3D PL_FLAG_SI;
+ pl->pl_siginfo =3D td2->td_dbgksi.ksi_info;
+ }
+ }
+ if ((pl->pl_flags & PL_FLAG_SI) =3D=3D 0)
+ bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
if (td2->td_dbgflags & TDB_SCE)
pl->pl_flags |=3D PL_FLAG_SCE;
else if (td2->td_dbgflags & TDB_SCX)
@@ -1120,6 +1175,10 @@ kern_ptrace(struct thread *td, int req, pid_t pid, v=
oid *addr, int data)
pl->pl_flags |=3D PL_FLAG_EXEC;
pl->pl_sigmask =3D td2->td_sigmask;
pl->pl_siglist =3D td2->td_siglist;
+#ifdef COMPAT_FREEBSD32
+ if (wrap32)
+ ptrace_lwpinfo_to32(pl, pl32);
+#endif
break;
=20
case PT_GETNUMLWPS:
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 3c9a2de..cd00550 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -259,6 +259,7 @@ struct thread {
char td_name[MAXCOMLEN + 1]; /* (*) Thread name. */
struct file *td_fpop; /* (k) file referencing cdev under op */
int td_dbgflags; /* (c) Userland debugger flags */
+ struct ksiginfo td_dbgksi; /* (c) ksi reflected to debugger. */
int td_ng_outbound; /* (k) Thread entered ng from above. */
struct osd td_osd; /* (k) Object specific data. */
#define td_endzero td_base_pri
diff --git a/sys/sys/ptrace.h b/sys/sys/ptrace.h
index a6dbe2c..f4b25d4 100644
--- a/sys/sys/ptrace.h
+++ b/sys/sys/ptrace.h
@@ -33,7 +33,7 @@
#ifndef _SYS_PTRACE_H_
#define _SYS_PTRACE_H_
=20
-#include <sys/_sigset.h>
+#include <sys/signal.h>
#include <machine/reg.h>
=20
#define PT_TRACE_ME 0 /* child declares it's being traced */
@@ -102,8 +102,10 @@ struct ptrace_lwpinfo {
#define PL_FLAG_SCE 0x04 /* syscall enter point */
#define PL_FLAG_SCX 0x08 /* syscall leave point */
#define PL_FLAG_EXEC 0x10 /* exec(2) succeeded */
+#define PL_FLAG_SI 0x20 /* siginfo is valid */
sigset_t pl_sigmask; /* LWP signal mask */
sigset_t pl_siglist; /* LWP pending signal */
+ struct __siginfo pl_siginfo; /* siginfo for signal */
};
=20
/* Argument structure for PT_VM_ENTRY. */
--w9Xseu/t+w8u+RRD
Content-Type: application/pgp-signature
Content-Disposition: inline
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (FreeBSD)
iEYEARECAAYFAkwsmzkACgkQC3+MBN1Mb4ilGgCglKAG92I6om1+whCrt1gAY+WZ
lC0AnAhdBxREUd2SU0xeOwL3aXWIxuIf
=aH25
-----END PGP SIGNATURE-----
--w9Xseu/t+w8u+RRD--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20100701134217.GM13238>