svn commit: r319875 - in head: lib/libc/sys sys/kern sys/sys
Konstantin Belousov
kib at FreeBSD.org
Mon Jun 12 21:15:44 UTC 2017
Author: kib
Date: Mon Jun 12 21:15:43 2017
New Revision: 319875
URL: https://svnweb.freebsd.org/changeset/base/319875
Log:
Add ptrace(PT_GET_SC_ARGS) command to return debuggee' current syscall
arguments.
Reviewed by: jhb (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Differential revision: https://reviews.freebsd.org/D11080
Modified:
head/lib/libc/sys/ptrace.2
head/sys/kern/sys_process.c
head/sys/sys/ptrace.h
Modified: head/lib/libc/sys/ptrace.2
==============================================================================
--- head/lib/libc/sys/ptrace.2 Mon Jun 12 21:11:11 2017 (r319874)
+++ head/lib/libc/sys/ptrace.2 Mon Jun 12 21:15:43 2017 (r319875)
@@ -2,7 +2,7 @@
.\" $NetBSD: ptrace.2,v 1.2 1995/02/27 12:35:37 cgd Exp $
.\"
.\" This file is in the public domain.
-.Dd August 29, 2016
+.Dd June 11, 2017
.Dt PTRACE 2
.Os
.Sh NAME
@@ -643,6 +643,26 @@ and
.Fa data
arguments are used the same as for
.Dv PT_CONTINUE.
+.It Dv PT_GET_SC_ARGS
+For the thread which is stopped in either
+.Dv PL_FLAG_SCE
+or
+.Dv PL_FLAG_SCX
+state, that is, on entry or exit to a syscall,
+this request fetches the syscall arguments.
+.Pp
+The arguments are copied out into the buffer pointed to by the
+.Fa addr
+pointer, sequentially.
+Each syscall argument is stored as the machine word.
+Kernel copies out as many arguments as the syscall accepts,
+see the
+.Va pl_syscall_narg
+member of the
+.Vt struct ptrace_lwpinfo ,
+but not more than the
+.Fa data
+bytes in total are copied.
.It Dv PT_FOLLOW_FORK
This request controls tracing for new child processes of a traced process.
If
Modified: head/sys/kern/sys_process.c
==============================================================================
--- head/sys/kern/sys_process.c Mon Jun 12 21:11:11 2017 (r319874)
+++ head/sys/kern/sys_process.c Mon Jun 12 21:15:43 2017 (r319875)
@@ -586,6 +586,7 @@ sys_ptrace(struct thread *td, struct ptrace_args *uap)
struct ptrace_lwpinfo32 pl32;
struct ptrace_vm_entry32 pve32;
#endif
+ char args[nitems(td->td_sa.args) * sizeof(register_t)];
int ptevents;
} r;
void *addr;
@@ -606,6 +607,7 @@ sys_ptrace(struct thread *td, struct ptrace_args *uap)
case PT_GETFPREGS:
case PT_GETDBREGS:
case PT_LWPINFO:
+ case PT_GET_SC_ARGS:
break;
case PT_SETREGS:
error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
@@ -663,6 +665,10 @@ sys_ptrace(struct thread *td, struct ptrace_args *uap)
/* NB: The size in uap->data is validated in kern_ptrace(). */
error = copyout(&r.pl, uap->addr, uap->data);
break;
+ case PT_GET_SC_ARGS:
+ error = copyout(r.args, uap->addr, MIN(uap->data,
+ sizeof(r.args)));
+ break;
}
return (error);
@@ -739,6 +745,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, voi
case PT_GET_EVENT_MASK:
case PT_SET_EVENT_MASK:
case PT_DETACH:
+ case PT_GET_SC_ARGS:
sx_xlock(&proctree_lock);
proctree_locked = 1;
break;
@@ -1008,6 +1015,28 @@ kern_ptrace(struct thread *td, int req, pid_t pid, voi
CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
p->p_pid, p->p_ptevents, tmp);
p->p_ptevents = tmp;
+ break;
+
+ case PT_GET_SC_ARGS:
+ CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
+ if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
+#ifdef COMPAT_FREEBSD32
+ || (wrap32 && !safe)
+#endif
+ ) {
+ error = EINVAL;
+ break;
+ }
+ bzero(addr, sizeof(td2->td_sa.args));
+#ifdef COMPAT_FREEBSD32
+ if (wrap32)
+ for (num = 0; num < nitems(td2->td_sa.args); num++)
+ ((uint32_t *)addr)[num] = (uint32_t)
+ td2->td_sa.args[num];
+ else
+#endif
+ bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
+ sizeof(register_t));
break;
case PT_STEP:
Modified: head/sys/sys/ptrace.h
==============================================================================
--- head/sys/sys/ptrace.h Mon Jun 12 21:11:11 2017 (r319874)
+++ head/sys/sys/ptrace.h Mon Jun 12 21:15:43 2017 (r319875)
@@ -69,6 +69,8 @@
#define PT_GET_EVENT_MASK 25 /* get mask of optional events */
#define PT_SET_EVENT_MASK 26 /* set mask of optional events */
+#define PT_GET_SC_ARGS 27 /* fetch syscall args */
+
#define PT_GETREGS 33 /* get general-purpose registers */
#define PT_SETREGS 34 /* set general-purpose registers */
#define PT_GETFPREGS 35 /* get floating-point registers */
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