d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Implement the PT_LWPINFO request. This request can be used by the

Browse Source 
tracing process to obtain information about the LWP that caused the
traced process to stop. Debuggers can use this information to select
the thread currently running on the LWP as the current thread.

The request has been made compatible with NetBSD for as much as
possible. This implementation differs from NetBSD in the following
ways:
1.  The data argument is allowed to be smaller than the size of the
    ptrace_lwpinfo structure known to the kernel, but not 0. This
    is opposite to what NetBSD allows. The reason for this is that
    we can extend the structure without affecting older binaries.
2.  On NetBSD the tracing process is to set the pl_lwpid field to
    the Id of the LWP it wants information of. We don't do that.
    Our ptrace interface allows passing the LWP Id instead of the
    PID. The tracing process is to set the PID to the LWP Id it
    wants information of.
3.  When the PID is actually the PID of the tracing process, this
    request returns the information about the LWP that caused the
    process to stop. This was the whole purpose of the request in
    the first place.

When the traced process has exited, this request will return the
LWP Id 0, indicating that the process state is not the result of
an event specific to a LWP.
This commit is contained in:
marcel 2004-07-12 05:07:50 +00:00
parent 221d6a099a
commit 57e7de678f
5 changed files with 33 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/kern/kern_exit.c
View File

@ -429,6 +429,7 @@ exit1(struct thread *td, int rv)
mtx_lock(&Giant);
PROC_LOCK(p);
p->p_xstat = rv;
p->p_xlwpid = td->td_tid;
*p->p_ru = p->p_stats->p_ru;
mtx_lock_spin(&sched_lock);
calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);

3
sys/kern/kern_sig.c
View File

@ -1882,6 +1882,7 @@ do_tdsignal(struct thread *td, int sig, sigtarget_t target)
goto out;
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
p->p_xlwpid = td->td_tid;
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(p, td0) {
if (TD_IS_SLEEPING(td0) &&
@ -2011,6 +2012,7 @@ ptracestop(struct thread *td, int sig)
&p->p_mtx.mtx_object, "Stopping for traced signal");
p->p_xstat = sig;
p->p_xlwpid = td->td_tid;
PROC_LOCK(p->p_pptr);
psignal(p->p_pptr, SIGCHLD);
PROC_UNLOCK(p->p_pptr);
@ -2154,6 +2156,7 @@ issignal(td)
&p->p_mtx.mtx_object, "Catching SIGSTOP");
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
p->p_xlwpid = td->td_tid;
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(p, td0) {
if (TD_IS_SLEEPING(td0) &&

19
sys/kern/sys_process.c
View File

@ -305,6 +305,7 @@ ptrace(struct thread *td, struct ptrace_args *uap)
*/
union {
struct ptrace_io_desc piod;
struct ptrace_lwpinfo pl;
struct dbreg dbreg;
struct fpreg fpreg;
struct reg reg;
@ -317,6 +318,7 @@ ptrace(struct thread *td, struct ptrace_args *uap)
case PT_GETREGS:
case PT_GETFPREGS:
case PT_GETDBREGS:
case PT_LWPINFO:
break;
case PT_SETREGS:
error = copyin(uap->addr, &r.reg, sizeof r.reg);
@ -354,6 +356,9 @@ ptrace(struct thread *td, struct ptrace_args *uap)
case PT_GETDBREGS:
error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg);
break;
case PT_LWPINFO:
error = copyout(&r.pl, uap->addr, uap->data);
break;
}
return (error);
@ -367,6 +372,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
struct proc *curp, *p, *pp;
struct thread *td2 = NULL;
struct ptrace_io_desc *piod;
struct ptrace_lwpinfo *pl;
int error, write, tmp;
int proctree_locked = 0;
lwpid_t tid = 0;
@ -606,6 +612,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
/* deliver or queue signal */
if (P_SHOULDSTOP(p)) {
p->p_xstat = data;
p->p_xlwpid = 0;
p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG);
mtx_lock_spin(&sched_lock);
thread_unsuspend(p);
@ -727,6 +734,17 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
PROC_UNLOCK(p);
return (error);
case PT_LWPINFO:
if (data == 0 || data > sizeof(*pl))
return (EINVAL);
pl = addr;
_PHOLD(p);
pl->pl_lwpid = p->p_xlwpid;
_PRELE(p);
PROC_UNLOCK(p);
pl->pl_event = PL_EVENT_SIGNAL;
return (0);
default:
#ifdef __HAVE_PTRACE_MACHDEP
if (req >= PT_FIRSTMACH) {
@ -764,6 +782,7 @@ stopevent(struct proc *p, unsigned int event, unsigned int val)
p->p_step = 1;
do {
p->p_xstat = val;
p->p_xlwpid = 0;
p->p_stype = event; /* Which event caused the stop? */
wakeup(&p->p_stype); /* Wake up any PIOCWAIT'ing procs */
msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);

1
sys/sys/proc.h
View File

@ -602,6 +602,7 @@ struct proc {
#define p_endcopy p_xstat
u_short p_xstat; /* (c) Exit status; also stop sig. */
lwpid_t p_xlwpid; /* (c) Thread corresponding p_xstat. */
int p_numthreads; /* (j) Number of threads. */
int p_numksegrps; /* (?) number of ksegrps */
struct mdproc p_md; /* Any machine-dependent fields. */

9
sys/sys/ptrace.h
View File

@ -47,6 +47,7 @@
#define PT_ATTACH 10 /* trace some running process */
#define PT_DETACH 11 /* stop tracing a process */
#define PT_IO 12 /* do I/O to/from stopped process. */
#define PT_LWPINFO 13 /* Info about the LWP that stopped. */
#define PT_TO_SCE 20
#define PT_TO_SCX 21
@ -77,6 +78,14 @@ struct ptrace_io_desc {
#define PIOD_READ_I 3 /* Read from I space */
#define PIOD_WRITE_I 4 /* Write to I space */
/* Argument structure for PT_LWPINFO. */
struct ptrace_lwpinfo {
lwpid_t pl_lwpid; /* LWP described. */
int pl_event; /* Event that stopped the LWP. */
#define PL_EVENT_NONE 0
#define PL_EVENT_SIGNAL 1
};
#ifdef _KERNEL
#define PTRACESTOP_SC(p, td, flag) \