* gdbstub initial code, v12
@ 2010-09-30 18:27 Oleg Nesterov
2010-10-04 18:14 ` Oleg Nesterov
0 siblings, 1 reply; 10+ messages in thread
From: Oleg Nesterov @ 2010-09-30 18:27 UTC (permalink / raw)
To: archer, utrace-devel
[-- Attachment #1: Type: text/plain, Size: 1017 bytes --]
Changes: fully implement g/G/p/P. Well, allmost.
I didn't expect this is so hairy. And, unfortunately, all
this code is x86 specific. I tried to avoid this very much,
but failed.
Also, it doesn't really support FPU. gdb has its own idea
about FPU regs and uses struct i387_fxsave. I failed to
understand i387_fxsave_to_cache/i387_cache_to_fxsave,
probably I'll simply copy-and-paste this code later.
Right now $G doesn't change FPU registers. $P does, but
mostly incorrectly.
Why gdb doesn't use $p after $P? It always fetches all
registers via $G, I don't even know how can I test $p.
Perhaps because gdbserver doesn't implement p/P.
Btw, I didn't veryfy this, but gdbserver looks obviously
wrong wrt 64/32 bit support. "struct reg *reg_defs" is global,
it is initalized by ->arch_setup() when we attach the first
inferior (or a new one after detach). But every inferior
needs its own reg_defs, I think. Otherwize even the simplest
x86_fill_gregset/x86_store_gregset can be confused.
Next: watchpoints.
Oleg.
[-- Attachment #2: ugdb.c --]
[-- Type: text/plain, Size: 64630 bytes --]
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/utrace.h>
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/regset.h>
#include <asm/uaccess.h>
static int o_remote_debug;
module_param_named(echo, o_remote_debug, bool, 0);
#define BUFFER_SIZE 1152
#define PACKET_SIZE 1152
struct pbuf {
char *cur, *pkt;
char buf[BUFFER_SIZE];
};
static inline void pb_init(struct pbuf *pb)
{
pb->cur = pb->buf;
pb->pkt = NULL;
}
enum {
U_STOP_IDLE = 0,
U_STOP_PENDING,
U_STOP_SENT,
};
struct ugdb {
struct list_head u_processes;
struct list_head u_stopped;
int u_stop_state;
struct mutex u_mutex;
spinlock_t u_slock;
struct ugdb_thread
*u_cur_tinfo,
*u_cur_hg,
*u_cur_hc;
wait_queue_head_t u_wait;
int u_err;
struct pbuf u_pbuf;
char u_cbuf[PACKET_SIZE];
int u_clen;
sigset_t u_sig_ign;
unsigned int
u_no_ack:1,
u_allstop:1;
};
static inline void ugdb_ck_stopped(struct ugdb *ugdb)
{
spin_lock(&ugdb->u_slock);
WARN_ON(!list_empty(&ugdb->u_stopped) &&
ugdb->u_stop_state == U_STOP_IDLE);
WARN_ON(list_empty(&ugdb->u_stopped) &&
ugdb->u_stop_state == U_STOP_PENDING);
spin_unlock(&ugdb->u_slock);
}
static struct ugdb *ugdb_create(void)
{
struct ugdb *ugdb;
int err;
err = -ENODEV;
// XXX: ugly. proc_reg_open() should take care.
if (!try_module_get(THIS_MODULE))
goto out;
err = -ENOMEM;
ugdb = kzalloc(sizeof(*ugdb), GFP_KERNEL);
if (!ugdb)
goto put_module;
INIT_LIST_HEAD(&ugdb->u_processes);
INIT_LIST_HEAD(&ugdb->u_stopped);
mutex_init(&ugdb->u_mutex);
spin_lock_init(&ugdb->u_slock);
init_waitqueue_head(&ugdb->u_wait);
pb_init(&ugdb->u_pbuf);
return ugdb;
put_module:
module_put(THIS_MODULE);
out:
return ERR_PTR(err);
}
#define P_DETACHING (1 << 1)
#define P_ZOMBIE (1 << 2)
struct ugdb_process {
int p_pid;
int p_state;
struct list_head p_threads;
struct ugdb *p_ugdb;
struct list_head p_processes;
};
static inline bool process_alive(struct ugdb_process *process)
{
return !(process->p_state & P_ZOMBIE);
}
static inline void mark_process_dead(struct ugdb_process *process)
{
process->p_state |= P_ZOMBIE;
}
static struct ugdb_process *ugdb_create_process(struct ugdb *ugdb, int pid_nr)
{
struct ugdb_process *process;
process = kzalloc(sizeof(*process), GFP_KERNEL);
if (!process)
return NULL;
process->p_pid = pid_nr;
process->p_ugdb = ugdb;
INIT_LIST_HEAD(&process->p_threads);
list_add_tail(&process->p_processes, &ugdb->u_processes);
return process;
}
#define T_STOP_RUN 0
#define T_STOP_REQ (1 << 0) /* requested by gdb */
#define T_STOP_ALL (1 << 1) /* vCont;c:pX.-1, for report_clone */
#define T_STOP_ACK (1 << 2) /* visible to vStopped */
#define T_STOP_STOPPED (1 << 3) /* reported as stopped to gdb */
/* TASK_TRACED + deactivated ? */
#define T_EV_NONE 0
#define T_EV_EXIT (1 << 24)
#define T_EV_SIGN (2 << 24)
#define T_EV_TYPE(event) ((0xff << 24) & (event))
#define T_EV_DATA(event) (~(0xff << 24) & (event))
struct ugdb_thread {
int t_tid;
int t_stop_state;
int t_stop_event;
bool t_step; // XXX: move me into t_stop_event
siginfo_t *t_siginfo;
struct ugdb *t_ugdb;
struct ugdb_process *t_process;
struct list_head t_threads;
struct list_head t_stopped;
struct pid *t_spid;
struct utrace_engine *t_engine;
};
static inline bool thread_alive(struct ugdb_thread *thread)
{
WARN_ON((thread->t_tid != 0) != process_alive(thread->t_process));
return thread->t_tid != 0;
}
static inline void mark_thread_dead(struct ugdb_thread *thread)
{
mark_process_dead(thread->t_process);
thread->t_tid = 0;
}
/*
* The thread should be alive, and it can't pass ugdb_report_death()
* if the caller holds ugdb->u_mutex. However the tracee can be
* reaped anyway, pid_task() can return NULL after detach_pid().
*/
static inline struct task_struct *thread_to_task(struct ugdb_thread *thread)
{
BUG_ON(!thread_alive(thread));
return pid_task(thread->t_spid, PIDTYPE_PID);
}
static struct ugdb_thread *ugdb_create_thread(struct ugdb_process *process,
struct pid *spid)
{
struct ugdb_thread *thread;
thread = kzalloc(sizeof(*thread), GFP_KERNEL);
if (!thread)
return NULL;
thread->t_tid = pid_vnr(spid);
thread->t_spid = get_pid(spid);
thread->t_process = process;
thread->t_ugdb = process->p_ugdb;
INIT_LIST_HEAD(&thread->t_stopped);
list_add_tail(&thread->t_threads, &process->p_threads);
return thread;
}
static void ugdb_del_stopped(struct ugdb *ugdb, struct ugdb_thread *thread)
{
if (!list_empty(&thread->t_stopped)) {
WARN_ON(!(thread->t_stop_state & T_STOP_ACK));
spin_lock(&ugdb->u_slock);
list_del_init(&thread->t_stopped);
if (!(thread->t_stop_state & T_STOP_STOPPED)) {
if (ugdb->u_stop_state == U_STOP_PENDING &&
list_empty(&ugdb->u_stopped))
ugdb->u_stop_state = U_STOP_IDLE;
}
spin_unlock(&ugdb->u_slock);
}
thread->t_stop_state = T_STOP_RUN;
}
static void ugdb_destroy_thread(struct ugdb_thread *thread)
{
struct ugdb *ugdb = thread->t_ugdb;
ugdb_ck_stopped(ugdb);
ugdb_del_stopped(ugdb, thread);
/* NULL if attach fails */
if (thread->t_engine)
utrace_engine_put(thread->t_engine);
list_del(&thread->t_threads);
put_pid(thread->t_spid);
kfree(thread);
}
static int ugdb_set_events(struct ugdb_thread *thread,
unsigned long events)
{
WARN_ON(!thread_alive(thread));
events |= (UTRACE_EVENT(CLONE) | UTRACE_EVENT(DEATH) |
UTRACE_EVENT_SIGNAL_ALL);
//XXX: I think utrace_get_signal() is buggy !!!!!!!!!!!!
events |= UTRACE_EVENT(QUIESCE);
return utrace_set_events_pid(thread->t_spid, thread->t_engine,
events);
}
static int ugdb_control(struct ugdb_thread *thread,
enum utrace_resume_action action)
{
// XXX: temporary racy check
WARN_ON(!thread_alive(thread) && action != UTRACE_DETACH);
return utrace_control_pid(thread->t_spid, thread->t_engine,
action);
}
static const struct utrace_engine_ops ugdb_utrace_ops;
static void ugdb_detach_thread(struct ugdb_thread *thread, bool running)
{
int ret;
ret = ugdb_control(thread, UTRACE_DETACH);
/* engine->flags == 0, it can't run a callback */
if (!running)
return;
/* callbacks are no longer possible */
if (!ret)
return;
if (ret == -EINPROGRESS) {
/*
* We raced with a callback, it can't be ->report_death().
* However, we can not use utrace_barrier_pid(), it can
* hang "forever" until the next utrace_resume() if it
* sees ->ops == &utrace_detached_ops set by us, but the
* tracee is no longer running.
*
* But: we have no choice.
*/
do {
ret = utrace_barrier_pid(thread->t_spid,
thread->t_engine);
} while (ret == -ERESTARTSYS);
} else {
/*
* Nothing can help us to synchronize with ->report_death.
* We do not know if it was already called or not, we can't
* know if it is running. utrace_barrier_pid() can't help,
* it can return zero and then later ->report_death() will
* be called. Or it can return -ESRCH just because the task
* was alredy released and pid_task() == NULL, but this
* doesn't mean ->report_death() can't be called later.
*
* Fortunately, we know that the tracee is dying or dead,
* engine->ops should be changed after ugdb_report_death()
* returns UTRACE_DETACH.
*/
while (thread->t_engine->ops == &ugdb_utrace_ops) {
schedule_timeout_uninterruptible(1);
}
}
}
/*
* returns NULL if raced with exit(), or ERR_PTR().
*/
static struct ugdb_thread *ugdb_attach_thread(struct ugdb_process *process,
struct pid *spid)
{
struct ugdb_thread *thread;
struct utrace_engine *engine;
struct task_struct *task;
thread = ugdb_create_thread(process, spid);
if (!thread)
goto err;
engine = utrace_attach_pid(thread->t_spid, UTRACE_ATTACH_CREATE,
&ugdb_utrace_ops, thread);
if (IS_ERR(engine))
goto free_thread;
thread->t_engine = engine;
if (ugdb_set_events(thread, 0))
goto detach_thread;
return thread;
detach_thread:
ugdb_detach_thread(thread, false);
free_thread:
ugdb_destroy_thread(thread);
err:
rcu_read_lock();
task = pid_task(spid, PIDTYPE_PID);
if (task && task->exit_state)
task = NULL;
rcu_read_unlock();
return task ? ERR_PTR(-ENOMEM) : NULL;
}
static inline bool is_subthread(struct ugdb_process *process,
struct ugdb_thread *thread)
{
return thread && thread->t_process == process;
}
static inline void ugdb_reset_tinfo(struct ugdb *ugdb)
{
ugdb->u_cur_tinfo = NULL;
}
static void ugdb_destroy_process(struct ugdb_process *process)
{
struct ugdb *ugdb = process->p_ugdb;
struct ugdb_thread *thread;
mutex_lock(&ugdb->u_mutex);
process->p_state |= P_DETACHING;
list_del(&process->p_processes);
if (is_subthread(process, ugdb->u_cur_hg))
ugdb->u_cur_hg = NULL;
if (is_subthread(process, ugdb->u_cur_hc))
ugdb->u_cur_hc = NULL;
/* I hope gdb won't do detach from under qfThreadInfo */
if (ugdb->u_cur_tinfo) {
printk(KERN_WARNING "ugdb: detach from under qfThreadInfo\n");
ugdb_reset_tinfo(ugdb);
}
mutex_unlock(&ugdb->u_mutex);
while (!list_empty(&process->p_threads)) {
thread = list_first_entry(&process->p_threads,
struct ugdb_thread, t_threads);
ugdb_detach_thread(thread, true);
ugdb_destroy_thread(thread);
}
BUG_ON(!list_empty(&process->p_threads));
kfree(process);
}
static void ugdb_destroy(struct ugdb *ugdb)
{
struct ugdb_process *process;
while (!list_empty(&ugdb->u_processes)) {
process = list_first_entry(&ugdb->u_processes,
struct ugdb_process, p_processes);
ugdb_destroy_process(process);
}
BUG_ON(!list_empty(&ugdb->u_processes));
BUG_ON(!list_empty(&ugdb->u_stopped));
module_put(THIS_MODULE);
kfree(ugdb);
}
static struct pid *get_next_pid(struct pid *main, struct pid *curr)
{
struct task_struct *task;
struct sighand_struct *sighand;
struct pid *next = NULL;
rcu_read_lock();
/*
* If task/sighand is NULL we return NULL. This is fine if
* the caller is get_first_pid(), we should abort attaching.
*
* But this can also happen if curr was already attached,
* and this is wrong. Fortunately, this is very unlikely
* case. The attached sub-thread can't pass ->report_death,
* if it was reaped the caller of release_task() must be
* ptracer who re-parented this thread.
*/
task = pid_task(curr, PIDTYPE_PID);
if (!task)
goto unlock_rcu;
// XXX: we need lock_task_sighand() but it is not exported,
// so we ran race with de_thread().
sighand = rcu_dereference(task->sighand);
if (!sighand)
goto unlock_rcu;
spin_lock_irq(&sighand->siglock);
for (;;) {
task = next_thread(task);
// XXX: if main is not leader we can race with exec.
if (task_pid(task) == main)
break;
if (!task->exit_state) {
next = get_pid(task_pid(task));
break;
}
}
spin_unlock_irq(&sighand->siglock);
unlock_rcu:
rcu_read_unlock();
return next;
}
static struct pid *get_first_pid(struct pid *main)
{
struct task_struct *leader;
rcu_read_lock();
leader = pid_task(main, PIDTYPE_PID);
if (leader && leader->exit_state)
leader = NULL;
rcu_read_unlock();
/*
* The group-leader is alive, try to attach. If it exits
* before utrace_set_events(), get_first_pid() will be
* called again and it will notice ->exit_state != 0.
*/
if (leader)
return get_pid(main);
/*
* Try to find the live sub-thread. If the whole group
* is dead it returns NULL and the caller aborts.
*/
return get_next_pid(main, main);
}
static int ugdb_attach_all_threads(struct ugdb *ugdb,
struct ugdb_process *process,
struct pid *main_pid)
{
struct ugdb_thread *thread;
struct pid *curr_pid;
mutex_lock(&ugdb->u_mutex);
for (;;) {
curr_pid = get_first_pid(main_pid);
if (!curr_pid)
goto abort;
thread = ugdb_attach_thread(process, curr_pid);
put_pid(curr_pid);
if (IS_ERR(thread))
goto abort;
if (thread)
break;
}
for (;;) {
struct pid *next_pid;
next_pid = get_next_pid(main_pid, curr_pid);
if (!next_pid)
break;
thread = ugdb_attach_thread(process, next_pid);
put_pid(next_pid);
if (IS_ERR(thread))
goto abort;
if (!thread)
continue;
curr_pid = next_pid;
}
mutex_unlock(&ugdb->u_mutex);
return 0;
abort:
mutex_unlock(&ugdb->u_mutex);
return -1;
}
static int ugdb_attach(struct ugdb *ugdb, int pid_nr)
{
struct pid *main_pid;
struct ugdb_process *process;
int err;
// XXX: check if exists
// XXX: check if group leader ?
err = -ESRCH;
main_pid = find_get_pid(pid_nr);
if (!main_pid)
goto out;
err = -ENOMEM;
process = ugdb_create_process(ugdb, pid_nr);
if (!process)
goto free_pid;
err = ugdb_attach_all_threads(ugdb, process, main_pid);
if (err)
ugdb_destroy_process(process);
free_pid:
put_pid(main_pid);
out:
return err;
}
static struct ugdb_process *ugdb_find_process(struct ugdb *ugdb, int pid)
{
struct ugdb_process *process;
list_for_each_entry(process, &ugdb->u_processes, p_processes) {
if (process->p_pid == pid)
return process;
}
return NULL;
}
static struct ugdb_thread *ugdb_find_thread(struct ugdb *ugdb, int pid, int tid)
{
struct ugdb_process *process;
struct ugdb_thread *thread;
list_for_each_entry(process, &ugdb->u_processes, p_processes) {
if (unlikely(!process_alive(process)))
continue;
if (pid && process->p_pid != pid)
continue;
list_for_each_entry(thread, &process->p_threads, t_threads) {
if (WARN_ON(!thread_alive(thread)))
continue;
if (!tid || thread->t_tid == tid)
return thread;
}
if (pid)
break;
}
return NULL;
}
static int ugdb_detach(struct ugdb *ugdb, int pid)
{
struct ugdb_process *process = ugdb_find_process(ugdb, pid);
if (!process)
return -1;
ugdb_destroy_process(process);
return 0;
}
#define CUR_TINFO_END ((struct ugdb_thread *)1)
static struct ugdb_thread *ugdb_advance_tinfo(struct ugdb *ugdb)
{
struct ugdb_thread *cur, *nxt;
struct ugdb_process *process;
cur = ugdb->u_cur_tinfo;
if (cur == CUR_TINFO_END) {
ugdb->u_cur_tinfo = NULL;
return NULL;
}
if (!cur) {
list_for_each_entry(process, &ugdb->u_processes, p_processes) {
if (unlikely(!process_alive(process)))
continue;
if (!list_empty(&process->p_threads)) {
cur = list_first_entry(&process->p_threads,
struct ugdb_thread, t_threads);
break;
}
}
if (!cur)
return NULL;
}
process = cur->t_process;
if (list_is_last(&cur->t_threads, &process->p_threads)) {
nxt = CUR_TINFO_END;
list_for_each_entry_continue(process, &ugdb->u_processes, p_processes) {
if (unlikely(!process_alive(process)))
continue;
if (!list_empty(&process->p_threads)) {
nxt = list_first_entry(&process->p_threads,
struct ugdb_thread, t_threads);
break;
}
}
} else {
nxt = list_first_entry(&cur->t_threads,
struct ugdb_thread, t_threads);
}
ugdb->u_cur_tinfo = nxt;
return cur;
}
// -----------------------------------------------------------------------------
static bool ugdb_add_stopped(struct ugdb_thread *thread, int stop_event)
{
struct ugdb *ugdb = thread->t_ugdb;
bool ret = false;
ugdb_ck_stopped(ugdb);
spin_lock(&ugdb->u_slock);
if (stop_event == T_EV_NONE) {
if (WARN_ON(thread->t_stop_state & T_STOP_ACK))
goto unlock;
if (WARN_ON(!list_empty(&thread->t_stopped)))
goto unlock;
/* raced with ugdb_cont_thread() */
if (!(thread->t_stop_state & T_STOP_REQ))
goto unlock;
}
if (thread->t_stop_state & T_STOP_ACK) {
if (thread->t_stop_state & T_STOP_STOPPED)
/*
* Alas, we can't report this event. We already
* reported T00 and there is no way to inform gdb
* the state of tracee was changed.
*/
goto unlock;
} else {
WARN_ON(thread->t_stop_state & T_STOP_STOPPED);
thread->t_stop_state |= T_STOP_ACK;
list_add_tail(&thread->t_stopped, &ugdb->u_stopped);
if (ugdb->u_stop_state == U_STOP_IDLE) {
ugdb->u_stop_state = U_STOP_PENDING;
wake_up_all(&ugdb->u_wait);
}
}
thread->t_stop_event = stop_event;
ret = true;
unlock:
spin_unlock(&ugdb->u_slock);
return ret;
}
static void ugdb_process_exit(struct ugdb_thread *thread)
{
struct ugdb *ugdb = thread->t_ugdb;
int status;
BUG_ON(!thread_alive(thread));
ugdb_del_stopped(ugdb, thread);
mark_thread_dead(thread);
// XXX: OOPS, we can't read ->signal->group_exit_code !!!
status = current->exit_code;
if (ugdb_add_stopped(thread, T_EV_EXIT | status))
return;
WARN_ON(1);
}
static int ugdb_stop_thread(struct ugdb_thread *thread, bool all)
{
struct ugdb *ugdb = thread->t_ugdb;
int err;
WARN_ON(!thread_alive(thread));
ugdb_ck_stopped(ugdb);
if (thread->t_stop_state != T_STOP_RUN) {
if (!all || (thread->t_stop_state & T_STOP_ALL))
return 0;
/*
* Otherwise we should set T_STOP_ALL anyway,
*
* (gdb) interrupt &
* (gbd) interrupt -a &
*
* to ensure -a actually works if it races with clone.
*/
}
err = -EALREADY;
spin_lock(&ugdb->u_slock);
if (thread->t_stop_state == T_STOP_RUN) {
thread->t_stop_state = T_STOP_REQ;
err = 0;
}
/*
* We hold ugdb->u_mutex, we can't race with ugdb_report_clone().
* ugdb->u_slock protects us against ugdb_add_stopped(). We can
* change ->t_stop_state even if we did not initiate this stop.
*/
if (all)
thread->t_stop_state |= T_STOP_ALL;
spin_unlock(&ugdb->u_slock);
if (err)
return 0;
// XXX: we don't do UTRACE_STOP! this means we can't
// stop TASK_STOPEED task. Need to discuss jctl issues.
// if we do UTRACE_STOP we should call ugdb_add_stopped().
ugdb_set_events(thread, UTRACE_EVENT(QUIESCE));
err = ugdb_control(thread, UTRACE_INTERRUPT);
if (err && err != -EINPROGRESS)
return err;
return 1;
}
static int ugdb_cont_thread(struct ugdb_thread *thread, bool all, bool step)
{
struct ugdb *ugdb = thread->t_ugdb;
int ret;
WARN_ON(!thread_alive(thread));
ugdb_ck_stopped(ugdb);
// XXX: gdb shouldn't explicitly cont an unreported thread
WARN_ON(!all && !(thread->t_stop_state & T_STOP_STOPPED));
if (thread->t_stop_state == T_STOP_RUN)
return 0;
spin_lock(&ugdb->u_slock);
/*
* Nothing to do except clear the pending T_STOP_REQ.
*/
ret = 0;
if (!(thread->t_stop_state & T_STOP_ACK))
goto set_run;
/*
* Alas. Thanks to remote protocol, we can't cont this
* thread. We probably already sent the notification, we
* can do nothing except ack that %Stop later in response
* to vStopped.
*
* OTOH, gdb shouldn't send 'c' if this thread was not
* reported as stopped. However, this means that gdb can
* see the new %Stop:T00 notification after vCont;c:pX.-1,
* it should handle this case correctly anyway. I hope.
*
* If this stop was not initiated by gdb we should not
* cancel it too, this event should be reported first.
*/
ret = -1;
if (!(thread->t_stop_state & T_STOP_STOPPED))
goto unlock;
ret = 1;
list_del_init(&thread->t_stopped);
set_run:
thread->t_stop_state = T_STOP_RUN;
unlock:
spin_unlock(&ugdb->u_slock);
if (ret >= 0) {
unsigned long events = 0;
enum utrace_resume_action action = UTRACE_RESUME;
thread->t_step = step;
if (step) {
/* to correctly step over syscall insn */
events |= UTRACE_EVENT(SYSCALL_EXIT);
action = UTRACE_SINGLESTEP;
}
// XXX: OK, this all is racy, and I do not see any
// solution except: implement UTRACE_STOP_STICKY and
// move this code up under the lock, or add
// utrace_engine_ops->notify_stopped().
// 1. UTRACE_RESUME is racy, this is fixeable.
// 2. we need utrace_barrier() to close the race
// with the callback which is going to return
// UTRACE_STOP, but:
// a) we can deadlock (solveable)
// b) in this case UTRACE_RESUME can race with
// another stop initiated by tracee itself.
ugdb_set_events(thread, events);
ugdb_control(thread, action);
}
return ret;
}
static struct ugdb_thread *ugdb_next_stopped(struct ugdb *ugdb)
{
struct ugdb_thread *thread = NULL;
// XXX: temporary racy check
WARN_ON(ugdb->u_stop_state == U_STOP_IDLE);
spin_lock(&ugdb->u_slock);
if (list_empty(&ugdb->u_stopped)) {
ugdb->u_stop_state = U_STOP_IDLE;
} else {
ugdb->u_stop_state = U_STOP_SENT;
thread = list_first_entry(&ugdb->u_stopped,
struct ugdb_thread, t_stopped);
thread->t_stop_state |= T_STOP_STOPPED;
list_del_init(&thread->t_stopped);
}
spin_unlock(&ugdb->u_slock);
return thread;
}
// -----------------------------------------------------------------------------
static bool ugdb_stop_pending(struct ugdb_thread *thread)
{
if (!(thread->t_stop_state & T_STOP_REQ))
return false;
if (!(thread->t_stop_state & T_STOP_ACK))
return ugdb_add_stopped(thread, T_EV_NONE);
return true;
}
static u32 ugdb_report_quiesce(u32 action, struct utrace_engine *engine,
unsigned long event)
{
struct ugdb_thread *thread = engine->data;
WARN_ON(!thread_alive(thread));
/* ensure SIGKILL can't race with stop/cont in progress */
if (event != UTRACE_EVENT(DEATH)) {
if (ugdb_stop_pending(thread))
return UTRACE_STOP;
}
return utrace_resume_action(action);
}
static int cont_signal(struct ugdb_thread *thread,
struct k_sigaction *return_ka)
{
int signr = T_EV_DATA(thread->t_stop_event);
siginfo_t *info = thread->t_siginfo;
thread->t_siginfo = NULL;
if (WARN_ON(!valid_signal(signr)))
return 0;
if (!signr)
return signr;
/*
* Update the siginfo structure if the signal has changed.
*/
if (info->si_signo != signr) {
info->si_signo = signr;
info->si_errno = 0;
info->si_code = SI_USER;
info->si_pid = 0;
info->si_uid = 0;
}
/* If the (new) signal is now blocked, requeue it. */
if (sigismember(¤t->blocked, signr)) {
send_sig_info(signr, info, current);
signr = 0;
} else {
spin_lock_irq(¤t->sighand->siglock);
*return_ka = current->sighand->action[signr - 1];
spin_unlock_irq(¤t->sighand->siglock);
}
return signr;
}
static u32 ugdb_report_signal(u32 action, struct utrace_engine *engine,
struct pt_regs *regs,
siginfo_t *info,
const struct k_sigaction *orig_ka,
struct k_sigaction *return_ka)
{
struct ugdb_thread *thread = engine->data;
struct ugdb *ugdb = thread->t_ugdb;
int signr;
WARN_ON(!thread_alive(thread));
switch (utrace_signal_action(action)) {
case UTRACE_SIGNAL_HANDLER:
if (WARN_ON(thread->t_siginfo))
thread->t_siginfo = NULL;
if (thread->t_step) {
WARN_ON(orig_ka);
// user_single_step_siginfo(current, regs, info);
memset(info, 0, sizeof(*info));
info->si_signo = SIGTRAP;
break;
}
/* Fall through */
default:
if (orig_ka)
break;
/*
* It was UTRACE_SIGNAL_REPORT, but another tracer has
* changed utrace_report->result to deliver or stop.
* Fall through.
*/
case UTRACE_SIGNAL_REPORT:
if (!thread->t_siginfo) {
/* UTRACE_INTERRUPT from ugdb_report_syscall_exit() */
if (thread->t_step) {
WARN_ON(orig_ka);
// user_single_step_siginfo(current, regs, info);
memset(info, 0, sizeof(*info));
info->si_signo = SIGTRAP;
break;
}
} else {
if (WARN_ON(thread->t_siginfo != info))
return action;
WARN_ON(T_EV_TYPE(thread->t_stop_event) != T_EV_SIGN);
signr = cont_signal(thread, return_ka);
if (signr) {
/*
* Consider:
*
* (gdb) signal SIG &
* (gdb) interrupt
*
* We shouldn't miss the new stop request, so
* we do not return from here.
*/
action = UTRACE_RESUME | UTRACE_SIGNAL_DELIVER;
}
}
if (ugdb_stop_pending(thread))
return UTRACE_STOP | utrace_signal_action(action);
if (thread->t_step)
return UTRACE_SINGLESTEP | utrace_signal_action(action);
return action;
}
WARN_ON(thread->t_siginfo);
signr = info->si_signo;
if (WARN_ON(!signr || !valid_signal(signr)))
return action;
if (sigismember(&ugdb->u_sig_ign, signr))
return action;
if (ugdb_add_stopped(thread, T_EV_SIGN | signr)) {
thread->t_siginfo = info;
/*
* Make sure the subsequent UTRACE_SIGNAL_REPORT clears
* ->t_siginfo before return from get_signal_to_deliver().
*/
if (utrace_control(current, engine, UTRACE_INTERRUPT))
WARN_ON(1);
return UTRACE_STOP | UTRACE_SIGNAL_IGN;
}
/*
* We already reported T00 to gdb. We can't change our state,
* we are already stopped from gdb pov. Push back this signal
* to report it later, after "continue".
*
* Not multitrace-friendly.
*/
return UTRACE_STOP | UTRACE_SIGNAL_REPORT | UTRACE_SIGNAL_HOLD;
}
static u32 ugdb_report_syscall_exit(u32 action, struct utrace_engine *engine,
struct pt_regs *regs)
{
struct ugdb_thread *thread = engine->data;
if (thread->t_step)
return UTRACE_INTERRUPT;
printk(KERN_INFO "ugdb: unexpected SYSCALL_EXIT\n");
return action;
}
static bool is_already_attached(struct ugdb_process *process,
struct task_struct *task)
{
struct ugdb_thread *thread;
if (likely(!task_utrace_flags(task)))
return false;
/*
* Currently there is no way to know if it was attached by us.
* We can't trust utrace_attach_task(UTRACE_ATTACH_MATCH_OPS),
* ugdb attaches without UTRACE_ATTACH_EXCLUSIVE. We have to
* check every attached thread.
*
* This is really bad, but without multitracing this can only
* happen in unlikely case right after ugdb_attach_all_threads().
*/
list_for_each_entry(thread, &process->p_threads, t_threads) {
if (thread->t_spid == task_pid(task))
return true;
}
return false;
}
static u32 ugdb_report_clone(u32 action, struct utrace_engine *engine,
unsigned long clone_flags,
struct task_struct *task)
{
struct ugdb_thread *thread = engine->data;
struct ugdb_process *process = thread->t_process;
struct ugdb *ugdb = thread->t_ugdb;
struct ugdb_thread *new_thread;
WARN_ON(!thread_alive(thread));
if (!(clone_flags & CLONE_THREAD))
goto out;
mutex_lock(&ugdb->u_mutex);
if (process->p_state & P_DETACHING)
goto unlock;
/*
* This can only happen if we raced with ugdb_attach() which
* could attach both current and the new PF_STARTING child.
*/
if (unlikely(is_already_attached(process, task)))
goto unlock;
new_thread = ugdb_attach_thread(process, task_pid(task));
BUG_ON(!new_thread);
if (WARN_ON(IS_ERR(new_thread)))
goto unlock;
if (thread->t_stop_state & T_STOP_ALL)
ugdb_stop_thread(new_thread, false);
unlock:
mutex_unlock(&ugdb->u_mutex);
out:
return utrace_resume_action(action);
}
static u32 ugdb_report_death(struct utrace_engine *engine,
bool group_dead, int signal)
{
struct ugdb_thread *thread = engine->data;
struct ugdb_process *process = thread->t_process;
struct ugdb *ugdb = thread->t_ugdb;
WARN_ON(!thread_alive(thread));
mutex_lock(&ugdb->u_mutex);
if (process->p_state & P_DETACHING)
goto unlock;
if (ugdb->u_cur_hg == thread)
ugdb->u_cur_hg = NULL;
if (ugdb->u_cur_hc == thread)
ugdb->u_cur_hc = NULL;
if (ugdb->u_cur_tinfo == thread)
ugdb_advance_tinfo(ugdb);
if (list_is_singular(&process->p_threads))
ugdb_process_exit(thread);
else
ugdb_destroy_thread(thread);
unlock:
mutex_unlock(&ugdb->u_mutex);
return UTRACE_DETACH;
}
static const struct utrace_engine_ops ugdb_utrace_ops = {
.report_quiesce = ugdb_report_quiesce,
.report_signal = ugdb_report_signal,
.report_syscall_exit = ugdb_report_syscall_exit,
.report_clone = ugdb_report_clone,
.report_death = ugdb_report_death,
};
// -----------------------------------------------------------------------------
static inline int pb_size(struct pbuf *pb)
{
return pb->cur - pb->buf;
}
static inline int pb_room(struct pbuf *pb)
{
return pb->buf + BUFFER_SIZE - pb->cur;
}
static inline void pb_putc(struct pbuf *pb, char c)
{
if (WARN_ON(pb->cur >= pb->buf + BUFFER_SIZE-1))
return;
*pb->cur++ = c;
}
static void pb_memcpy(struct pbuf *pb, const void *data, int size)
{
if (WARN_ON(size > pb_room(pb)))
return;
memcpy(pb->cur, data, size);
pb->cur += size;
}
static inline void pb_puts(struct pbuf *pb, const char *s)
{
pb_memcpy(pb, s, strlen(s));
}
static inline void pb_putb(struct pbuf *pb, unsigned char val)
{
static char hex[] = "0123456789abcdef";
pb_putc(pb, hex[(val & 0xf0) >> 4]);
pb_putc(pb, hex[(val & 0x0f) >> 0]);
}
static void pb_putbs(struct pbuf *pb, const char *data, int size)
{
while (size--)
pb_putb(pb, *data++);
}
static inline void __pb_start(struct pbuf *pb, char pref)
{
WARN_ON(pb->pkt);
pb_putc(pb, pref);
pb->pkt = pb->cur;
}
static inline void pb_start(struct pbuf *pb)
{
return __pb_start(pb, '$');
}
static inline void pb_cancel(struct pbuf *pb)
{
if (WARN_ON(!pb->pkt))
return;
pb->cur = pb->pkt - 1;
pb->pkt = NULL;
}
static void pb_end(struct pbuf *pb)
{
unsigned char csm = 0;
char *pkt = pb->pkt;
pb->pkt = NULL;
if (WARN_ON(!pkt))
return;
while (pkt < pb->cur) {
/* pb_qfer() can write '%' */
WARN_ON(*pkt == '$' || *pkt == '#');
csm += (unsigned char)*pkt++;
}
pb_putc(pb, '#');
pb_putb(pb, csm);
}
static inline void pb_packs(struct pbuf *pb, const char *s)
{
pb_start(pb);
pb_puts(pb, s);
pb_end(pb);
}
static void __attribute__ ((format(printf, 3, 4)))
__pb_format(struct pbuf *pb, bool whole_pkt, const char *fmt, ...)
{
int room = pb_room(pb), size;
va_list args;
if (whole_pkt)
pb_start(pb);
va_start(args, fmt);
size = vsnprintf(pb->cur, room, fmt, args);
va_end(args);
if (WARN_ON(size > room))
return;
pb->cur += size;
if (whole_pkt)
pb_end(pb);
}
#define pb_printf(pb, args...) __pb_format((pb), false, args)
#define pb_packf(pb, args...) __pb_format((pb), true, args)
static int pb_qfer(struct pbuf *pb, const void *_data, int len, bool more)
{
const unsigned char *data = _data;
int i;
if (pb_room(pb) < 3 + len * 2) {
WARN_ON(1);
return -EOVERFLOW;
}
pb_start(pb);
pb_putc(pb, more ? 'm' : 'l');
for (i = 0; i < len; ++i) {
unsigned char c = data[i];
if (c == '$' || c == '#' || c == '}' || c == '*') {
pb_putc(pb, '}');
c ^= 0x20;
}
pb_putc(pb, c);
}
pb_end(pb);
return 0;
}
static inline void *pb_alloc_bs(struct pbuf *pb, int size)
{
if (unlikely(pb_room(pb) < 2 * size + 4))
return NULL;
return pb->cur + size + 1;
}
static inline void *pb_alloc_tmp(struct pbuf *pb, int size)
{
if (unlikely(pb_room(pb) < size))
return NULL;
return pb->cur + BUFFER_SIZE - size;
}
static inline void pb_flush(struct pbuf *pb, int size)
{
int keep = pb_size(pb) - size;
if (keep)
memmove(pb->buf, pb->buf + size, keep);
pb->cur -= size;
}
static int pb_copy_to_user(struct pbuf *pb, char __user *ubuf, int size)
{
int copy = min(size, pb_size(pb));
if (!copy)
return -EAGAIN;
if (o_remote_debug)
printk(KERN_INFO "<= %.*s\n", min(copy, 64), pb->buf);
if (copy_to_user(ubuf, pb->buf, copy))
return -EFAULT;
pb_flush(pb, copy);
return copy;
}
// -----------------------------------------------------------------------------
// XXX: include/gdb/signals.h:target_signal
// incomplete: 7, 29, rt?
static int to_gdb_sigmap[] = {
[SIGHUP] = 1,
[SIGINT] = 2,
[SIGQUIT] = 3,
[SIGILL] = 4,
[SIGTRAP] = 5,
[SIGABRT] = 6,
[SIGIOT] = 0, /* ??? */
[SIGBUS] = 10,
[SIGFPE] = 8,
[SIGKILL] = 9,
[SIGUSR1] = 30,
[SIGSEGV] = 11,
[SIGUSR2] = 31,
[SIGPIPE] = 13,
[SIGALRM] = 14,
[SIGTERM] = 15,
[SIGSTKFLT] = 0, /* ??? */
[SIGCHLD] = 20,
[SIGCONT] = 19,
[SIGSTOP] = 17,
[SIGTSTP] = 18,
[SIGTTIN] = 21,
[SIGTTOU] = 22,
[SIGURG] = 16,
[SIGXCPU] = 24,
[SIGXFSZ] = 25,
[SIGVTALRM] = 26,
[SIGPROF] = 27,
[SIGWINCH] = 28,
[SIGIO] = 23,
[SIGPWR] = 32,
[SIGSYS] = 12,
};
static int sig_to_gdb(unsigned sig)
{
if (sig < ARRAY_SIZE(to_gdb_sigmap) && to_gdb_sigmap[sig])
return to_gdb_sigmap[sig];
return sig;
}
static int sig_from_gdb(unsigned sig)
{
int i;
// XXX: valid_signal() is wrong, gdb has its own idea
// about signals. fix to_gdb_sigmap[].
if (!sig || !valid_signal(sig))
return 0;
for (i = 0; i < ARRAY_SIZE(to_gdb_sigmap); i++) {
if (to_gdb_sigmap[i] == sig)
return i;
}
return sig;
}
static int ugdb_report_stopped(struct ugdb *ugdb, bool async)
{
struct ugdb_thread *thread;
int pid, tid, event, data;
struct pbuf *pb;
char ex_r;
mutex_lock(&ugdb->u_mutex);
thread = ugdb_next_stopped(ugdb);
if (!thread)
goto unlock;
event = thread->t_stop_event;
WARN_ON(thread_alive(thread) != (T_EV_TYPE(event) != T_EV_EXIT));
pid = thread->t_process->p_pid;
tid = thread->t_tid;
unlock:
mutex_unlock(&ugdb->u_mutex);
if (!thread)
return false;
pb = &ugdb->u_pbuf;
// XXX: damn, cleanup me...
if (async) {
__pb_start(pb, '%');
pb_puts(pb, "Stop:");
} else {
pb_start(pb);
}
data = T_EV_DATA(event);
switch (T_EV_TYPE(event)) {
case T_EV_EXIT:
if (data & 0xff) {
data = sig_to_gdb(data & 0xff);
ex_r = 'X';
} else {
data >>= 8;
ex_r = 'W';
}
pb_printf(pb, "%c%x;process:%x", ex_r, data, pid);
ugdb_destroy_process(thread->t_process);
break;
case T_EV_SIGN:
case T_EV_NONE:
pb_printf(pb, "T%02xthread:p%x.%x;",
sig_to_gdb(data), pid, tid);
break;
default:
printk(KERN_INFO "ugdb: bad stop event %x\n", event);
}
pb_end(pb);
return true;
}
const char *handle_vstopped(struct ugdb *ugdb)
{
if (ugdb->u_stop_state != U_STOP_SENT)
return "E01";
if (ugdb_report_stopped(ugdb, false))
return NULL;
return "OK";
}
static const char *handle_thread_info(struct ugdb *ugdb, bool start)
{
struct ugdb_thread *thread;
int pid = 0, tid;
mutex_lock(&ugdb->u_mutex);
if (start)
ugdb_reset_tinfo(ugdb);
else if (!ugdb->u_cur_tinfo)
printk(KERN_INFO "ugdb: unexpected qsThreadInfo\n");
thread = ugdb_advance_tinfo(ugdb);
if (thread) {
pid = thread->t_process->p_pid;
tid = thread->t_tid;
}
mutex_unlock(&ugdb->u_mutex);
if (!pid)
return start ? "E01" : "l";
pb_packf(&ugdb->u_pbuf, "mp%x.%x", pid, tid);
return NULL;
}
static char *parse_xid(char *str, int *ppid, bool multi)
{
if (*str == '-') {
str++;
if (multi && *str++ == '1')
*ppid = -1;
else
str = NULL;
} else {
char *cur = str;
*ppid = simple_strtoul(cur, &str, 16);
if (str == cur)
str = NULL;
}
return str;
}
static char *parse_pid_tid(char *str, int *ppid, int *ptid, bool multi)
{
if (*str++ != 'p')
return NULL;
str = parse_xid(str, ppid, multi);
if (!str)
return NULL;
if (*str++ != '.')
return NULL;
str = parse_xid(str, ptid, multi);
if (!str)
return NULL;
return str;
}
static const char *handle_set_cur(struct ugdb *ugdb, char *cmd)
{
struct ugdb_thread **pthread;
int pid, tid;
switch (*cmd++) {
case 'g':
pthread = &ugdb->u_cur_hg;
break;
case 'c':
pthread = &ugdb->u_cur_hc;
break;
default:
goto err;
}
if (!parse_pid_tid(cmd, &pid, &tid, false))
goto err;
mutex_lock(&ugdb->u_mutex);
*pthread = ugdb_find_thread(ugdb, pid, tid);
mutex_unlock(&ugdb->u_mutex);
if (*pthread)
return "OK";
err:
return "E01";
}
static const char *handle_ck_alive(struct ugdb *ugdb, char *cmd)
{
struct ugdb_thread *thread;
int pid = 0, tid;
if (!parse_pid_tid(cmd, &pid, &tid, false))
goto err;
mutex_lock(&ugdb->u_mutex);
thread = ugdb_find_thread(ugdb, pid, tid);
mutex_unlock(&ugdb->u_mutex);
if (thread)
return "OK";
err:
return "E01";
}
static int parse_pid(char *str)
{
int pid;
if (!parse_xid(str, &pid, false))
return 0;
return pid;
}
static const char *handle_vattach(struct ugdb *ugdb, char *cmd)
{
int pid = parse_pid(cmd);
if (pid && !ugdb_attach(ugdb, pid))
return "OK";
return "E01";
}
static const char *handle_detach(struct ugdb *ugdb, char *cmd)
{
int pid;
if (*cmd++ != ';')
goto err;
pid = parse_pid(cmd);
if (pid && !ugdb_detach(ugdb, pid))
return "OK";
err:
return "E01";
}
typedef int (*each_func_t)(struct ugdb_thread *, void *);
static int ugdb_do_each_thread(struct ugdb *ugdb, int pid, int tid,
each_func_t func, void *arg)
{
struct ugdb_process *process;
struct ugdb_thread *thread;
int ret = -ESRCH;
list_for_each_entry(process, &ugdb->u_processes, p_processes) {
if (unlikely(!process_alive(process)))
continue;
if (pid > 0 && process->p_pid != pid)
continue;
list_for_each_entry(thread, &process->p_threads, t_threads) {
if (WARN_ON(!thread_alive(thread)))
continue;
if (tid > 0 && thread->t_tid != tid)
continue;
ret = func(thread, arg);
if (ret)
goto out;
if (tid >= 0)
break;
}
if (pid >= 0)
break;
}
out:
return ret;
}
static int do_stop_thread(struct ugdb_thread *thread, void *arg)
{
ugdb_stop_thread(thread, arg != NULL);
return 0;
}
static int do_cont_thread(struct ugdb_thread *thread, void *arg)
{
ugdb_cont_thread(thread, arg != NULL, false);
return 0;
}
static const char *handle_vcont(struct ugdb *ugdb, char *cmd)
{
int pid, tid;
void *arg;
int ret;
switch (*cmd ++) {
default:
return "E01";
case '?':
return "vCont;t";
case ';':
break;
}
// XXX: Discuss the generic case! currently trivial.
if (*cmd++ != 't')
return "E01";
pid = tid = -1;
if (*cmd++ == ':') {
if (!parse_pid_tid(cmd, &pid, &tid, true))
return "E01";
}
arg = (tid >= 0) ? NULL : (void*)1;
mutex_lock(&ugdb->u_mutex);
// XXX: currently we only report -ESRCH
ret = ugdb_do_each_thread(ugdb, pid, tid, do_stop_thread, arg);
mutex_unlock(&ugdb->u_mutex);
return ret < 0 ? "E01" : "OK";
}
static int thread_cont_signal(struct ugdb_thread *thread, int signr)
{
/*
* T_STOP_STOPPED was set under ->u_slock so we can't race
* with ugdb_add_stopped() and get the wrong t_stop_event.
* And, the tracee never changes it after T_STOP_STOPPED.
*/
switch (T_EV_TYPE(thread->t_stop_event)) {
case T_EV_SIGN:
WARN_ON(!T_EV_DATA(thread->t_stop_event));
thread->t_stop_event = T_EV_SIGN | signr;
break;
default:
if (!signr)
break;
// XXX: temporary hack, will be reported.
// but perhaps this is what we want ???
kill_pid(thread->t_spid, signr, 0);
break;
}
return 0;
}
static const char *handle_c(struct ugdb *ugdb, char *cmd)
{
struct ugdb_thread *thread;
const char *rc = "E01";
int gdbsig, signr = 0;
bool step;
step = (*cmd == 'S' || *cmd == 's');
switch (*cmd++) {
case 'C':
case 'S':
gdbsig = simple_strtoul(cmd, &cmd, 16);
if (!gdbsig)
return rc;
signr = sig_from_gdb(gdbsig);
if (!signr)
printk(KERN_INFO "ugdb: sorry, can't map signal %d\n",
gdbsig);
if (*cmd == ';')
++cmd;
/* fall */
case 'c':
case 's':
if (!*cmd)
break;
printk(KERN_INFO "ugdb: $c ADDR not implemented\n");
return rc;
break;
}
mutex_lock(&ugdb->u_mutex);
thread = ugdb->u_cur_hc;
if (!thread)
goto unlock;
/*
* Otherwise I do not know what to do if sig/step, and anyway
* I don't think gdb can try to cont a thread which was not
* reported as stopped.
*/
if (!(thread->t_stop_state & T_STOP_STOPPED))
goto unlock;
if (thread_cont_signal(thread, signr))
goto unlock;
if (ugdb_cont_thread(thread, false, step) <= 0)
goto unlock;
rc = "OK";
unlock:
mutex_unlock(&ugdb->u_mutex);
return rc;
}
static const char *handle_qpass_signals(struct ugdb *ugdb, char *cmd)
{
sigset_t *set = &ugdb->u_sig_ign;
sigemptyset(set);
while (*cmd) {
char *end;
int sig = simple_strtoul(cmd, &end, 16);
if (cmd == end || *end != ';')
return "E01";
cmd = end + 1;
sig = sig_from_gdb(sig);
if (!sig)
// XXX: to_gdb_sigmap[] incomplete...
// return "E01";
continue;
sigaddset(set, sig);
}
return "OK";
}
// -----------------------------------------------------------------------------
static struct task_struct *
ugdb_prepare_examine(struct ugdb *ugdb, struct utrace_examiner *exam)
{
struct ugdb_thread *thread;
struct task_struct *task;
int err;
mutex_lock(&ugdb->u_mutex);
thread = ugdb->u_cur_hg;
if (!thread || !(thread->t_stop_state & T_STOP_STOPPED))
goto err;
// XXX: u_cur_hg can't exit, we hold the mutex
task = thread_to_task(thread);
if (!task)
goto err;
for (;;) {
if (fatal_signal_pending(current))
goto err;
err = utrace_prepare_examine(task, thread->t_engine, exam);
if (!err)
break;
if (err == -ESRCH)
goto err;
schedule_timeout_interruptible(1);
}
return task;
err:
mutex_unlock(&ugdb->u_mutex);
return NULL;
}
// XXX: we hold the mutex in between, but only because we can't
// use get_task_struct/put_task_struct.
static int
ugdb_finish_examine(struct ugdb *ugdb, struct utrace_examiner *exam)
{
// XXX: u_cur_hg can't exit, we hold the mutex
struct ugdb_thread *thread = ugdb->u_cur_hg;
struct task_struct *task = thread_to_task(thread);
int ret = -ESRCH;
if (task)
ret = utrace_finish_examine(task, thread->t_engine, exam);
mutex_unlock(&ugdb->u_mutex);
return ret;
}
#define REGSET_GENERAL 0
#define REGSET_FP 1
// stolen from gdb-7.1/gdb/gdbserver/linux-x86-low.c
static int x86_64_regmap[] = {
80, 40, 88, 96, 104, 112, 32, 152, 72, 64, 56, 48, 24, 16,
8, 0, 128, 144, 136, 160, 184, 192, 200, 208, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 120,
};
static char *handle_getregs(struct ugdb *ugdb)
{
struct utrace_examiner exam;
struct task_struct *task;
const struct user_regset_view *view;
const struct user_regset *rset;
struct user_regs_struct *pregs;
int rn;
static int pkt_size;
if (!pkt_size) {
int sz = 0;
for (rn = 0; rn < ARRAY_SIZE(x86_64_regmap); ++rn) {
int offs = x86_64_regmap[rn];
if (offs < 0)
continue;
if (offs > (sizeof(*pregs) - sizeof(long))) {
printk(KERN_INFO "XXX: x86_64_regmap is wrong!\n");
ugdb->u_err = -EINVAL;
goto err;
}
sz += sizeof(long) * 2;
}
pkt_size = sz;
}
if (pb_room(&ugdb->u_pbuf) < 4 + pkt_size + sizeof(*pregs)) {
printk(KERN_INFO "XXX: getregs ENOMEM %d %ld\n",
pkt_size, sizeof(*pregs));
goto err;
}
pregs = pb_alloc_tmp(&ugdb->u_pbuf, sizeof(*pregs));
BUG_ON(pregs + 1 != (void*)ugdb->u_pbuf.cur + BUFFER_SIZE);
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto err;
view = task_user_regset_view(task);
rset = view->regsets + REGSET_GENERAL;
rset->get(task, rset, 0, sizeof(*pregs), pregs, NULL);
if (ugdb_finish_examine(ugdb, &exam))
goto err;
pb_start(&ugdb->u_pbuf);
for (rn = 0; rn < ARRAY_SIZE(x86_64_regmap); ++rn) {
int offs = x86_64_regmap[rn];
if (offs >= 0)
pb_putbs(&ugdb->u_pbuf, (void*)pregs + offs,
sizeof(long));
}
WARN_ON(pb_room(&ugdb->u_pbuf) < sizeof(*pregs));
pb_end(&ugdb->u_pbuf);
return NULL;
err:
return "E01";
}
#define MAX_REG_SIZE 16
struct gdbreg {
unsigned short
gdb_size, gdb_offs,
rs_setno, usr_offs;
};
// gdb/gdbserver/i387-fp.c:i387_fxsave
struct gdb_i387_fxsave {
unsigned short fctrl;
unsigned short fstat;
unsigned short ftag;
unsigned short fop;
unsigned int fioff;
unsigned short fiseg;
unsigned short pad1;
unsigned int fooff;
unsigned short foseg;
unsigned short pad12;
unsigned int mxcsr;
unsigned int pad3;
unsigned char st_space[128];
unsigned char xmm_space[256];
};
#define FPU__(mem) \
.rs_setno = REGSET_FP, \
.usr_offs = offsetof(struct gdb_i387_fxsave, mem)
#define GEN__(mem) \
.rs_setno = REGSET_GENERAL, \
.usr_offs = offsetof(struct user_regs_struct, mem)
/* generated from gdb/regformats/reg-x86-64-linux.dat */
struct gdbreg gdb_regmap_64[] = {
[ 0] = { .gdb_size = 8, .gdb_offs = 0, GEN__(ax) },
[ 1] = { .gdb_size = 8, .gdb_offs = 8, GEN__(bx) },
[ 2] = { .gdb_size = 8, .gdb_offs = 16, GEN__(cx) },
[ 3] = { .gdb_size = 8, .gdb_offs = 24, GEN__(dx) },
[ 4] = { .gdb_size = 8, .gdb_offs = 32, GEN__(si) },
[ 5] = { .gdb_size = 8, .gdb_offs = 40, GEN__(di) },
[ 6] = { .gdb_size = 8, .gdb_offs = 48, GEN__(bp) },
[ 7] = { .gdb_size = 8, .gdb_offs = 56, GEN__(sp) },
[ 8] = { .gdb_size = 8, .gdb_offs = 64, GEN__(r8) },
[ 9] = { .gdb_size = 8, .gdb_offs = 72, GEN__(r9) },
[10] = { .gdb_size = 8, .gdb_offs = 80, GEN__(r10) },
[11] = { .gdb_size = 8, .gdb_offs = 88, GEN__(r11) },
[12] = { .gdb_size = 8, .gdb_offs = 96, GEN__(r12) },
[13] = { .gdb_size = 8, .gdb_offs = 104, GEN__(r13) },
[14] = { .gdb_size = 8, .gdb_offs = 112, GEN__(r14) },
[15] = { .gdb_size = 8, .gdb_offs = 120, GEN__(r15) },
[16] = { .gdb_size = 8, .gdb_offs = 128, GEN__(ip) },
[17] = { .gdb_size = 4, .gdb_offs = 136, GEN__(flags) },
[18] = { .gdb_size = 4, .gdb_offs = 140, GEN__(cs) },
[19] = { .gdb_size = 4, .gdb_offs = 144, GEN__(ss) },
[20] = { .gdb_size = 4, .gdb_offs = 148, GEN__(ds) },
[21] = { .gdb_size = 4, .gdb_offs = 152, GEN__(es) },
[22] = { .gdb_size = 4, .gdb_offs = 156, GEN__(fs) },
[23] = { .gdb_size = 4, .gdb_offs = 160, GEN__(gs) },
[24] = { .gdb_size = 10, .gdb_offs = 164, FPU__(st_space[0]) },
[25] = { .gdb_size = 10, .gdb_offs = 174, FPU__(st_space[16]) },
[26] = { .gdb_size = 10, .gdb_offs = 184, FPU__(st_space[32]) },
[27] = { .gdb_size = 10, .gdb_offs = 194, FPU__(st_space[48]) },
[28] = { .gdb_size = 10, .gdb_offs = 204, FPU__(st_space[64]) },
[29] = { .gdb_size = 10, .gdb_offs = 214, FPU__(st_space[80]) },
[30] = { .gdb_size = 10, .gdb_offs = 224, FPU__(st_space[96]) },
[31] = { .gdb_size = 10, .gdb_offs = 234, FPU__(st_space[112]) },
[32] = { .gdb_size = 4, .gdb_offs = 244, FPU__(fctrl) },
[33] = { .gdb_size = 4, .gdb_offs = 248, FPU__(fstat) },
[34] = { .gdb_size = 4, .gdb_offs = 252, FPU__(ftag) },
[35] = { .gdb_size = 4, .gdb_offs = 256, FPU__(fiseg) },
[36] = { .gdb_size = 4, .gdb_offs = 260, FPU__(fioff) },
[37] = { .gdb_size = 4, .gdb_offs = 264, FPU__(foseg) },
[38] = { .gdb_size = 4, .gdb_offs = 268, FPU__(fooff) },
[39] = { .gdb_size = 4, .gdb_offs = 272, FPU__(fop) },
[40] = { .gdb_size = 16, .gdb_offs = 276, FPU__(xmm_space[0]) },
[41] = { .gdb_size = 16, .gdb_offs = 292, FPU__(xmm_space[16]) },
[42] = { .gdb_size = 16, .gdb_offs = 308, FPU__(xmm_space[32]) },
[43] = { .gdb_size = 16, .gdb_offs = 324, FPU__(xmm_space[48]) },
[44] = { .gdb_size = 16, .gdb_offs = 340, FPU__(xmm_space[64]) },
[45] = { .gdb_size = 16, .gdb_offs = 356, FPU__(xmm_space[80]) },
[46] = { .gdb_size = 16, .gdb_offs = 372, FPU__(xmm_space[96]) },
[47] = { .gdb_size = 16, .gdb_offs = 388, FPU__(xmm_space[112]) },
[48] = { .gdb_size = 16, .gdb_offs = 404, FPU__(xmm_space[128]) },
[49] = { .gdb_size = 16, .gdb_offs = 420, FPU__(xmm_space[144]) },
[50] = { .gdb_size = 16, .gdb_offs = 436, FPU__(xmm_space[160]) },
[51] = { .gdb_size = 16, .gdb_offs = 452, FPU__(xmm_space[176]) },
[52] = { .gdb_size = 16, .gdb_offs = 468, FPU__(xmm_space[192]) },
[53] = { .gdb_size = 16, .gdb_offs = 484, FPU__(xmm_space[208]) },
[54] = { .gdb_size = 16, .gdb_offs = 500, FPU__(xmm_space[224]) },
[55] = { .gdb_size = 16, .gdb_offs = 516, FPU__(xmm_space[240]) },
[56] = { .gdb_size = 4, .gdb_offs = 532, FPU__(mxcsr) },
[57] = { .gdb_size = 8, .gdb_offs = 536, GEN__(orig_ax) },
};
#undef FPU__
#undef GEN__
static inline int rw_one_reg(struct task_struct *task, int regnum,
unsigned char regval[], bool write)
{
const struct user_regset_view *view;
const struct user_regset *rset;
struct gdbreg *gdbreg;
int err, count;
view = task_user_regset_view(task);
switch (view->e_machine) {
case EM_X86_64:
if (regnum >= ARRAY_SIZE(gdb_regmap_64))
return -EINVAL;
gdbreg = gdb_regmap_64;
count = sizeof(long);
break;
default:
return -EIO;
}
gdbreg += regnum;
rset = view->regsets + gdbreg->rs_setno;
if (gdbreg->rs_setno != REGSET_GENERAL)
count = gdbreg->gdb_size;
if (WARN_ON(count > MAX_REG_SIZE))
return -EOVERFLOW;
if (write)
err = rset->set(task, rset, gdbreg->usr_offs,
count, regval, NULL);
else
err = rset->get(task, rset, gdbreg->usr_offs,
count, regval, NULL);
return err ?: gdbreg->gdb_size;
}
static int ugdb_rw_one_reg(struct ugdb *ugdb, int regnum,
unsigned char regval[], bool write)
{
struct utrace_examiner exam;
struct task_struct *task;
int ret = -ESRCH;
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto ret;
ret = rw_one_reg(task, regnum, regval, write);
if (ugdb_finish_examine(ugdb, &exam))
ret = -ESRCH;
ret:
return ret;
}
// XXX: hex_to_bin() after 90378889 commit
#include <linux/ctype.h>
static int cap_hex_to_bin(char ch)
{
if ((ch >= '0') && (ch <= '9'))
return ch - '0';
ch = tolower(ch);
if ((ch >= 'a') && (ch <= 'f'))
return ch - 'a' + 10;
return -1;
}
static int unhex(char *cmd, int size)
{
char *bytes = cmd;
while (size--) {
int lo, hi;
hi = cap_hex_to_bin(*cmd++);
lo = cap_hex_to_bin(*cmd++);
if (lo < 0 || hi < 0)
return -EINVAL;
*bytes++ = (hi << 4) | lo;
}
return 0;
}
static const char *handle_set_reg(struct ugdb *ugdb, char *cmd, int len)
{
unsigned int reg;
int skip;
if (sscanf(cmd, "P%x=%n", ®, &skip) != 1)
goto err;
cmd += skip;
len -= skip;
if (len & 1)
goto err;
len /= 2;
if (unhex(cmd, len))
goto err;
if (ugdb_rw_one_reg(ugdb, reg, cmd, true) != len)
goto err;
return "OK";
err:
return "E01";
}
static const char *handle_get_reg(struct ugdb *ugdb, char *cmd, int len)
{
unsigned char regval[MAX_REG_SIZE];
unsigned int reg;
int skip, size;
if (sscanf(cmd, "p%x%n", ®, &skip) != 1)
goto err;
if (len != skip)
goto err;
size = ugdb_rw_one_reg(ugdb, reg, regval, false);
if (size < 0)
goto err;
pb_start(&ugdb->u_pbuf);
pb_putbs(&ugdb->u_pbuf, regval, size);
pb_end(&ugdb->u_pbuf);
return NULL;
err:
return "E01";
}
static int rw_one_regset(struct task_struct *task, int rsn,
const struct user_regset_view *view,
void *reg_mem, int reg_size,
struct gdbreg *reg_map, int reg_cnt,
void *gdb_mem, bool write)
{
const struct user_regset *rset = view->regsets + rsn;
int err;
if (write) {
for (; reg_cnt--; ++reg_map) {
if (reg_map->rs_setno != rsn)
continue;
memcpy(reg_mem + reg_map->usr_offs,
gdb_mem + reg_map->gdb_offs,
reg_map->gdb_size);
}
err = rset->set(task, rset, 0, reg_size, reg_mem, NULL);
} else {
err = rset->get(task, rset, 0, reg_size, reg_mem, NULL);
if (err)
goto ret;
for (; reg_cnt--; ++reg_map) {
if (reg_map->rs_setno != rsn)
continue;
memcpy(gdb_mem + reg_map->gdb_offs,
reg_mem + reg_map->usr_offs,
reg_map->gdb_size);
}
}
ret:
return err;
}
#define GDB_REGS_SIZE(regmap) \
(regmap[ARRAY_SIZE(regmap)-1].gdb_size + \
regmap[ARRAY_SIZE(regmap)-1].gdb_offs)
struct regs_buf {
unsigned char gdb_mem[1024];
union {
struct user_regs_struct user_regs_struct;
struct user_i387_struct user_i387_struct;
};
};
static int ugdb_rw_all_regs(struct task_struct *task,
struct regs_buf *regs_buf,
bool write)
{
const struct user_regset_view *view;
int ret;
#define RW(rsn, user, rmap) \
rw_one_regset(task, rsn, view, \
®s_buf->user, sizeof(regs_buf->user), \
rmap, ARRAY_SIZE(rmap), regs_buf->gdb_mem, \
write)
view = task_user_regset_view(task);
switch (view->e_machine) {
case EM_X86_64:
ret = RW(REGSET_GENERAL, user_regs_struct, gdb_regmap_64);
if (ret)
break;
// XXX: needs fixup
if (!write)
ret = RW(REGSET_FP, user_i387_struct, gdb_regmap_64);
if (ret)
break;
ret = GDB_REGS_SIZE(gdb_regmap_64);
break;
default:
ret = -EIO;
}
#undef RW
return ret;
}
static const char *handle_get_all_regs(struct ugdb *ugdb)
{
struct regs_buf *regs_buf;
struct utrace_examiner exam;
struct task_struct *task;
const char *ret = "E01";
int size;
regs_buf = kzalloc(sizeof(*regs_buf), GFP_KERNEL);
if (!regs_buf)
goto out;
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto err;
size = ugdb_rw_all_regs(task, regs_buf, false);
if (ugdb_finish_examine(ugdb, &exam))
goto err;
if (size < 0)
goto err;
if (size > sizeof(regs_buf->gdb_mem)) {
WARN_ON(1);
goto err;
}
if (pb_room(&ugdb->u_pbuf) < 3 + size * 2) {
WARN_ON(1);
goto err;
}
pb_start(&ugdb->u_pbuf);
pb_putbs(&ugdb->u_pbuf, regs_buf->gdb_mem, size);
pb_end(&ugdb->u_pbuf);
ret = NULL;
err:
kfree(regs_buf);
out:
return ret;
}
static const char *handle_set_all_regs(struct ugdb *ugdb, char *cmd, int len)
{
struct regs_buf *regs_buf;
struct utrace_examiner exam;
struct task_struct *task;
const char *ret = "E01";
int size;
printk(KERN_INFO "XXX: $G command, why?\n");
cmd += 1;
len -= 1;
if (len & 1)
goto out;
len /= 2;
if (unhex(cmd, len))
goto out;
regs_buf = kzalloc(sizeof(*regs_buf), GFP_KERNEL);
if (!regs_buf)
goto out;
memcpy(regs_buf->gdb_mem, cmd, len);
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto err;
size = ugdb_rw_all_regs(task, regs_buf, true);
if (ugdb_finish_examine(ugdb, &exam))
goto err;
if (size < 0)
goto err;
WARN_ON(size != len);
ret = "OK";
err:
kfree(regs_buf);
out:
return ret;
}
static typeof(access_process_vm) *u_access_process_vm;
static const char *handle_readmem(struct ugdb *ugdb, char *cmd)
{
struct utrace_examiner exam;
struct task_struct *task;
unsigned long addr, size;
unsigned char *mbuf;
int copied;
if (sscanf(cmd, "m%lx,%lx", &addr, &size) != 2)
goto err;
mbuf = pb_alloc_bs(&ugdb->u_pbuf, size);
if (!mbuf) {
printk(KERN_INFO "XXX: apvm(%ld) ENOMEM\n", size);
goto err;
}
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto err;
copied = u_access_process_vm(task, addr, mbuf, size, 0);
if (ugdb_finish_examine(ugdb, &exam))
goto err;
if (copied > 0 ) {
pb_start(&ugdb->u_pbuf);
pb_putbs(&ugdb->u_pbuf, mbuf, size);
pb_end(&ugdb->u_pbuf);
return NULL;
}
err:
return "E01";
}
static const char *handle_writemem(struct ugdb *ugdb, char *cmd, int len)
{
unsigned long addr, size;
unsigned int skip, written;
struct utrace_examiner exam;
struct task_struct *task;
if (sscanf(cmd, "M%lx,%lx:%n", &addr, &size, &skip) != 2)
goto err;
cmd += skip;
len -= skip;
if (len != 2*size || !size)
goto err;
if (unhex(cmd, size))
goto err;
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto err;
written = u_access_process_vm(task, addr, cmd, size, 1);
if (ugdb_finish_examine(ugdb, &exam))
goto err;
if (written == size)
return "OK";
err:
return "E01";
}
static int ugdb_siginfo_rw(struct ugdb *ugdb, siginfo_t *info, bool write)
{
struct task_struct *task;
struct utrace_examiner exam;
struct sighand_struct *sighand;
siginfo_t *t_siginfo;
int ret = -EINVAL;
/*
* ugdb_prepare_examine() is overkill, but otherwise we can't
* assume task_is_traced(), and this is what ensures we can
* safely read/write ->t_siginfo which points to task's stack.
*/
task = ugdb_prepare_examine(ugdb, &exam);
if (!task)
goto out;
/* OK, task_struct can't go away, but ->sighand can. */
rcu_read_lock();
sighand = rcu_dereference(task->sighand);
if (!sighand)
goto unlock_rcu;
spin_lock_irq(&sighand->siglock);
if (!task_is_traced(task))
goto unlock_siglock;
t_siginfo = ugdb->u_cur_hg->t_siginfo;
if (!t_siginfo)
goto unlock_siglock;
if (write)
*t_siginfo = *info;
else
*info = *t_siginfo;
ret = 0;
unlock_siglock:
spin_unlock_irq(&sighand->siglock);
unlock_rcu:
rcu_read_unlock();
ugdb_finish_examine(ugdb, &exam);
out:
return ret;
}
static const char *handle_siginfo_read(struct ugdb *ugdb, char *cmd)
{
unsigned int off, len;
siginfo_t info;
if (sscanf(cmd, "%x,%x", &off, &len) != 2)
goto err;
if (off >= sizeof(info))
goto err;
if (len > sizeof(info) || off + len > sizeof(info))
len = sizeof(info) - off;
if (ugdb_siginfo_rw(ugdb, &info, false))
goto err;
if (pb_qfer(&ugdb->u_pbuf, &info + off, len,
(off + len < sizeof(info))))
goto err;
// XXX: Oh. we also need x86_siginfo_fixup(). how ugly.
return NULL;
err:
return "E01";
}
// -----------------------------------------------------------------------------
#define EQ(cmd, str) \
(strncmp((cmd), (str), sizeof(str)-1) ? false : \
((cmd) += sizeof(str)-1, true))
static const char *handle_qfer(struct ugdb *ugdb, char *cmd)
{
const char *rc = "E01";
if (EQ(cmd, "siginfo:")) {
if (EQ(cmd, "read::"))
rc = handle_siginfo_read(ugdb, cmd);
}
return rc;
}
static void handle_command(struct ugdb *ugdb, char *cmd, int len)
{
struct pbuf *pb = &ugdb->u_pbuf;
const char *rc = "";
switch (cmd[0]) {
case '!':
case '?':
rc = "OK";
break;
case 'H':
rc = handle_set_cur(ugdb, cmd + 1);
break;
case 'T':
rc = handle_ck_alive(ugdb, cmd + 1);
break;
case 'D':
rc = handle_detach(ugdb, cmd + 1);
break;
case 'g':
if (0)
rc = handle_getregs(ugdb);
else
rc = handle_get_all_regs(ugdb);
break;
case 'G':
rc = handle_set_all_regs(ugdb, cmd, len);
break;
case 'p':
rc = handle_get_reg(ugdb, cmd, len);
break;
case 'P':
rc = handle_set_reg(ugdb, cmd, len);
break;
case 'm':
rc = handle_readmem(ugdb, cmd);
break;
case 'M':
rc = handle_writemem(ugdb, cmd, len);
break;
case 'C':
case 'c':
case 'S':
case 's':
rc = handle_c(ugdb, cmd);
break;
case 'q':
if (EQ(cmd, "qSupported")) {
if (!strstr(cmd, "multiprocess+")) {
printk(KERN_INFO "ugdb: can't work without multiprocess\n");
ugdb->u_err = -EPROTONOSUPPORT;
}
pb_packf(&ugdb->u_pbuf, "PacketSize=%x;%s",
PACKET_SIZE,
"QStartNoAckMode+;QNonStop+;multiprocess+;"
"QPassSignals+;qXfer:siginfo:read+");
rc = NULL;
}
else if (EQ(cmd, "qfThreadInfo")) {
rc = handle_thread_info(ugdb, true);
}
else if (EQ(cmd, "qsThreadInfo")) {
rc = handle_thread_info(ugdb, false);
}
else if (EQ(cmd, "qXfer:")) {
rc = handle_qfer(ugdb, cmd);
}
else if (EQ(cmd, "qTStatus")) {
rc = "T0";
}
break;
case 'Q':
if (EQ(cmd, "QStartNoAckMode")) {
ugdb->u_no_ack = true;
rc = "OK";
}
else if (EQ(cmd, "QNonStop:")) {
if (*cmd != '1') {
printk(KERN_INFO "ugdb: all-stop is not implemented.\n");
ugdb->u_err = -EPROTONOSUPPORT;
}
rc = "OK";
}
else if (EQ(cmd, "QPassSignals:")) {
rc = handle_qpass_signals(ugdb, cmd);
}
break;
case 'v':
if (EQ(cmd, "vAttach;")) {
rc = handle_vattach(ugdb, cmd);
}
else if (EQ(cmd, "vStopped")) {
rc = handle_vstopped(ugdb);
}
else if (EQ(cmd, "vCont")) {
rc = handle_vcont(ugdb, cmd);
}
break;
default:
;
}
if (rc)
pb_packs(pb, rc);
}
static void process_commands(struct ugdb *ugdb)
{
char *cmds = ugdb->u_cbuf;
int todo = ugdb->u_clen;
if (o_remote_debug)
printk(KERN_INFO "=> %.*s\n", ugdb->u_clen, ugdb->u_cbuf);
while (todo) {
char first;
char *c_cmd, *c_end;
int c_len;
first = *cmds++;
todo--;
switch (first) {
default:
printk(KERN_INFO "XXX: unknown chr %02x\n", first);
pb_putc(&ugdb->u_pbuf, '-');
break;
case '-':
printk(KERN_INFO "XXX: got NACK!\n");
ugdb->u_err = -EPROTO;
case '+':
break;
case 0x3:
printk(KERN_INFO "XXX: unexpected CTRL-C\n");
break;
case '$':
c_cmd = cmds;
c_end = strnchr(c_cmd, todo, '#');
c_len = c_end ? c_end - cmds : -1;
if (c_len < 0 || todo < c_len + 3) {
printk(KERN_INFO "XXX: can't find '#cs'\n");
++todo;
--cmds;
goto out;
}
// XXX: verify checksum ?
todo -= c_len + 3;
cmds += c_len + 3;
*c_end = 0;
if (!ugdb->u_no_ack)
pb_putc(&ugdb->u_pbuf, '+');
handle_command(ugdb, c_cmd, c_len);
}
}
out:
ugdb->u_clen = todo;
if (todo && cmds > ugdb->u_cbuf)
memmove(ugdb->u_cbuf, cmds, todo);
}
// -----------------------------------------------------------------------------
static int xxx_tinfo(struct ugdb *ugdb)
{
struct ugdb_thread *thread;
int tid = 0;
mutex_lock(&ugdb->u_mutex);
thread = ugdb_advance_tinfo(ugdb);
if (thread)
tid = thread->t_tid;
mutex_unlock(&ugdb->u_mutex);
return tid;
}
static int xxx_sc_threads(struct ugdb *ugdb, int tid, bool sc)
{
void *arg = NULL;
int pid = 0;
int ret;
if (tid < 0) {
pid = -tid;
tid = -1;
arg = (void*)1;
}
mutex_lock(&ugdb->u_mutex);
ret = ugdb_do_each_thread(ugdb, pid, tid,
sc ? do_stop_thread : do_cont_thread,
arg);
mutex_unlock(&ugdb->u_mutex);
return ret;
}
static int xxx_stop(struct ugdb *ugdb, int tid)
{
return xxx_sc_threads(ugdb, tid, true);
}
static int xxx_cont(struct ugdb *ugdb, int tid)
{
return xxx_sc_threads(ugdb, tid, false);
}
static int xxx_get_stopped(struct ugdb *ugdb)
{
struct ugdb_thread *thread;
int tid = 1;
if (ugdb->u_stop_state == U_STOP_IDLE)
return -1;
if (ugdb->u_stop_state == U_STOP_PENDING)
tid = 1000;
thread = ugdb_next_stopped(ugdb);
if (!thread)
return 0;
return tid * thread->t_tid;
}
static int xxx_show_all(struct ugdb *ugdb)
{
struct ugdb_process *process;
struct ugdb_thread *thread;
printk(KERN_INFO "SHOW start ----------------------------------------\n");
mutex_lock(&ugdb->u_mutex);
list_for_each_entry(process, &ugdb->u_processes, p_processes) {
printk(KERN_INFO "PROC: %x\n", process->p_pid);
list_for_each_entry(thread, &process->p_threads, t_threads) {
printk(KERN_INFO " T: %x %p; %p %p\n",
thread->t_tid, thread,
thread->t_spid, pid_task(thread->t_spid, PIDTYPE_PID));
}
}
mutex_unlock(&ugdb->u_mutex);
printk(KERN_INFO "SHOW end ----------------------------------------\n");
return 0;
}
static long ugdb_f_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct ugdb *ugdb = file->private_data;
// XXX: otherwise gdb->get_tty_state(TCGETS, TCSETS, TCFLSH) complains
int ret = 0;
// XXX: temporary debugging hooks, ignore.
switch (cmd) {
case 0x666 + 0:
ret = ugdb_attach(ugdb, arg);
break;
case 0x666 + 1:
ret = ugdb_detach(ugdb, arg);
break;
case 0x666 + 2:
ret = xxx_tinfo(ugdb);
break;
case 0x666 + 3:
ret = xxx_stop(ugdb, arg);
break;
case 0x666 + 4:
ret = xxx_cont(ugdb, arg);
break;
case 0x666 + 5:
ret = xxx_get_stopped(ugdb);
break;
case 0x666 + 6:
ret = xxx_show_all(ugdb);
break;
}
return ret;
}
static unsigned int ugdb_f_poll(struct file *file, poll_table *wait)
{
struct ugdb *ugdb = file->private_data;
unsigned int mask;
poll_wait(file, &ugdb->u_wait, wait);
mask = (POLLOUT | POLLWRNORM);
if (pb_size(&ugdb->u_pbuf) || ugdb->u_stop_state == U_STOP_PENDING)
mask |= (POLLIN | POLLRDNORM);
if (ugdb->u_err)
mask |= POLLERR;
return mask;
}
static ssize_t ugdb_f_read(struct file *file, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct ugdb *ugdb = file->private_data;
struct pbuf *pb = &ugdb->u_pbuf;
if (ugdb->u_err)
return ugdb->u_err;
if (ugdb->u_stop_state == U_STOP_PENDING)
ugdb_report_stopped(ugdb, true);
if (pb_size(pb) > count) {
printk(KERN_INFO "XXX: short read %d %ld\n",
pb_size(pb), count);
}
return pb_copy_to_user(pb, ubuf, count);
}
static ssize_t ugdb_f_write(struct file *file, const char __user *ubuf,
size_t count, loff_t *ppos)
{
struct ugdb *ugdb = file->private_data;
if (ugdb->u_err)
return ugdb->u_err;
if (count > PACKET_SIZE - ugdb->u_clen) {
count = PACKET_SIZE - ugdb->u_clen;
printk("XXX: write(%ld,%d) enospc\n", count, ugdb->u_clen);
if (1)
return ugdb->u_err = -ENOSPC;
}
if (copy_from_user(ugdb->u_cbuf + ugdb->u_clen, ubuf, count))
return -EFAULT;
ugdb->u_clen += count;
process_commands(ugdb);
return count;
}
static int ugdb_f_open(struct inode *inode, struct file *file)
{
nonseekable_open(inode, file);
file->private_data = ugdb_create();
return IS_ERR(file->private_data) ?
PTR_ERR(file->private_data) : 0;
}
static int ugdb_f_release(struct inode *inode, struct file *file)
{
ugdb_destroy(file->private_data);
return 0;
}
static const struct file_operations ugdb_f_ops = {
.open = ugdb_f_open,
.unlocked_ioctl = ugdb_f_ioctl,
.poll = ugdb_f_poll,
.read = ugdb_f_read,
.write = ugdb_f_write,
.release = ugdb_f_release,
};
#include <linux/kallsyms.h>
struct kallsyms_sym {
const char *name;
unsigned long addr;
};
static int kallsyms_on_each_symbol_cb(void *data, const char *name,
struct module *mod, unsigned long addr)
{
struct kallsyms_sym *sym = data;
if (strcmp(name, sym->name))
return 0;
sym->addr = addr;
return 1;
}
// XXX: kallsyms_lookup_name() is not exported in 2.6.32
static bool lookup_unexported(void)
{
struct kallsyms_sym sym;
sym.name = "access_process_vm";
if (!kallsyms_on_each_symbol(kallsyms_on_each_symbol_cb, &sym))
goto err;
u_access_process_vm = (void*)sym.addr;
return true;
err:
printk(KERN_ERR "ugdb: can't lookup %s\n", sym.name);
return false;
}
#define PROC_NAME "ugdb"
struct proc_dir_entry *ugdb_pde;
static int __init ugdb_init(void)
{
if (!lookup_unexported())
return -ESRCH;
ugdb_pde = proc_create(PROC_NAME, S_IFREG|S_IRUGO|S_IWUGO,
NULL, &ugdb_f_ops);
if (!ugdb_pde)
return -EBADF;
return 0;
}
static void __exit ugdb_exit(void)
{
remove_proc_entry(PROC_NAME, NULL);
}
MODULE_LICENSE("GPL");
module_init(ugdb_init);
module_exit(ugdb_exit);
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: gdbstub initial code, v12
2010-09-30 18:27 gdbstub initial code, v12 Oleg Nesterov
@ 2010-10-04 18:14 ` Oleg Nesterov
2010-10-05 17:31 ` BUG: gdb && notification packets (Was: gdbstub initial code, v12) Oleg Nesterov
0 siblings, 1 reply; 10+ messages in thread
From: Oleg Nesterov @ 2010-10-04 18:14 UTC (permalink / raw)
To: archer, utrace-devel
On 09/30, Oleg Nesterov wrote:
>
> Right now $G doesn't change FPU registers.
It turns out, $G can't even set the REGSET_GENERAL reg correctly.
I noticed this only because the tracee sometimes dies during the
single-stepping inside the dynamic linker. Indeed, $G passes the
wrong fs_index==0 to genregs_set().
> Next: watchpoints.
While trying to understand what does this mean, I hit another bug
in ugdb. A multithreaded tracee can "hang" if gdb simulates
watchpoints with single-steps + mem-fetch/compare. Still can't
understand why this happens, this should be resolved. This never
happens if the tracee is single-threaded.
Oleg.
^ permalink raw reply [flat|nested] 10+ messages in thread
* BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-04 18:14 ` Oleg Nesterov
@ 2010-10-05 17:31 ` Oleg Nesterov
2010-10-05 18:30 ` Pedro Alves
0 siblings, 1 reply; 10+ messages in thread
From: Oleg Nesterov @ 2010-10-05 17:31 UTC (permalink / raw)
To: archer, utrace-devel
On 10/04, Oleg Nesterov wrote:
>
> While trying to understand what does this mean, I hit another bug
> in ugdb.
No, /usr/bin/gdb is buggy.
> A multithreaded tracee can "hang" if gdb simulates
> watchpoints with single-steps + mem-fetch/compare.
It doesn't, but gdb "forgets" about the pending "Stop:" notification,
see below.
> This never
> happens if the tracee is single-threaded.
This is clear. And this doesn't happen with the real gdbbserver.
Probably timing issues, with ugdb the tracee can report itself
as stopped much faster (not because ugdb is faster, but because
it sends the notification before the tracee actually stops).
Consider this simplified artifitial test-case:
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
struct {
char x[128];
} VAR;
void *tfunc(void *arg)
{
for (;;)
;
}
int main(void)
{
pthread_t thr;
printf("pid: %d\n", getpid());
pthread_create(&thr, NULL, tfunc, NULL);
tfunc(NULL);
return 0;
}
It just creates 2 threads, each threads spins in the trivial endless loop.
VAR is the dummy variable for "watch", it is never changed. It should be big
enough to ensure can_use_hardware_watchpoint->default_region_ok_for_hw_watchpoint()
returns 0 and gdb falls back to simulating.
(gdb) set target-async on
(gdb) set non-stop
(gdb) target extended-remote :2000
(gdb) attach 1404
(gdb) watch VAR
(gdb) c -a
After that, sooner or later the tracee "hangs". gdb sleeps in poll(), both
traced threads sleep after reporting SIGTRAP (single-step).
The more or less "typical" transcript is:
[... snip ...]
=> s
<= OK
<= %Stop:T05thread:p57c.57d;
=> vStopped
<= T05thread:p57c.57c;
=> vStopped
<= OK
=> g
<= 50994242000000000000000000000000761f0a16677f000000000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> g
<= 50994242000000000000000000000000761f0a16677f000000000000000000...
=> s
<= OK
<= %Stop:T05thread:p57c.57d;
=> Hgp57c.57c
<= OK
=> g
<= 000000000000000030064000000000008162e115677f000000000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> Hcp57c.57c
<= OK
=> s#73$vStopped
<= OK#9a$OK
<= %Stop:T05thread:p57c.57c;
=> Hgp57c.57d#ec$g
<= OK#9a$50994242000000000000000000000000761f0a16677f000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> g
<= 50994242000000000000000000000000761f0a16677f000000000000000000...
=> Hcp57c.57d
<= OK
=> s#73$vStopped
<= OK#9a$OK
<= %Stop:T05thread:p57c.57d;
=> Hgp57c.57c
<= OK
=> g
<= 000000000000000030064000000000008162e115677f000000000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> Hcp57c.57c
<= OK
=> s#73$vStopped
<= OK#9a$OK
Everything is fine so far. And this is how it works with the real gdbserver:
gdb always issues vStopped until it gets the final "OK". Like it should,
I guess.
So. At this point gdb knows that 57d is stopped, and it sends '$s' to 57c.
<= %Stop:T05thread:p57c.57c;
57c reports the next stop, but gdb temporary "ignores" this notification
and plays with 57d. This is fine.
=> Hgp57c.57d#ec$g
<= OK#9a$50994242000000000000000000000000761f0a16677f000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> g
<= 50994242000000000000000000000000761f0a16677f000000000000000000...
=> Hcp57c.57d
<= OK
=> s#73$vStopped
Finally it does vStopped. But, by this time 57d is stopped again (note
that gdb sends '$s' before vStopped).
<= OK#9a$T05thread:p57c.57d;
ugdb reports 57d as stopped.
_If_ gdb sent vStopped right now, he would get "OK" in return. But it
doesn't. Again, this is not the bug yet.
=> Hgp57c.57c
<= OK
=> g
<= 000000000000000030064000000000008162e115677f000000000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> Hcp57c.57c
<= OK
=> s
<= OK
Now, 57c stops. But it can't report this stop. We are "inside" the
"vStopped" sequence, ugdb waits for gdb which should complete it
by sending the next vStopped packet which should find that 57c is
stopped.
From the documentation:
If the stub receives a `vStopped' packet and there are no additional
stop events to report, the stub shall return an `OK' response. At this
point, if further stop events occur, the stub shall send a new stop
reply notification,
IOW, 57c should not send the notification and it doesn't. But this confuses
gdb.
In short: gdb forgets that the last 'vStopped' didn't return 'OK' and
thus we probably have more stopped tracees but waits for the next
notification. ugdb doesn't send the notification because it shouldn't
do this until gdb sends the "final" vStopped according to the doc
above.
Another similar transcript:
[... snip ...]
=> Hcp589.589
<= OK
=> s
<= OK#9a%Stop:T05thread:p589.589;
=> vStopped
<= OK
=> g
<= 0000000000000000300640000000000081621fd01f7f000000000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> s
<= OK#9a%Stop:T05thread:p589.589;
=> vStopped
<= OK
=> g
<= 0000000000000000300640000000000081621fd01f7f000000000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> s#73$vStopped
<= OK#9a$T05thread:p589.589;
=> Hgp589.58a#c1$g
<= OK#9a$50990141000000000000000000000000761f48d01f7f000000000000...
=> m600a60,80
<= 00000000000000000000000000000000000000000000000000000000000000...
=> g
<= 50990141000000000000000000000000761f48d01f7f000000000000000000...
=> Hcp589.58a
<= OK
=> s
<= OK
Almost the same.
Once again, whatever I did I failed to reproduce this hang with the
real gdbserver.
So I hacked gdb to send the similar sequence of packets instead, and
result is the same:
getpkt ("Hcp589.589"); [no ack sent]
putpkt ("$OK#9a"); [noack mode]
getpkt ("s"); [no ack sent]
putpkt ("$OK#9a"); [noack mode]
pending stop replies: 1
putpkt ("%Stop:T0506:f089f2deff7f0* ;07:f089f2deff7f0* ;10:d40540*';thread:p589.589;core:1;#94"); [notif]
getpkt ("Hcp589.58a"); [no ack sent]
putpkt ("$OK#9a"); [noack mode]
getpkt ("s"); [no ack sent]
putpkt ("$OK#9a"); [noack mode]
pending stop replies: 2
getpkt ("vStopped"); [no ack sent]
vStopped: acking LWP 1417.1417
putpkt ("$T0506:309101410*"00;07:309101410*"00;10:d40540*';thread:p589.58a;core:1;#24"); [noack mode]
getpkt ("Hcp589.589"); [no ack sent]
putpkt ("$OK#9a"); [noack mode]
getpkt ("s"); [no ack sent]
putpkt ("$OK#9a"); [noack mode]
pending stop replies: 2
Like ugdb, gdbserver does NOT send the new notification, but waits for gdb
which should continue and complete the vStopped sequence.
So, I strongly believe gdb is buggy and should be fixed.
Oleg.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-05 17:31 ` BUG: gdb && notification packets (Was: gdbstub initial code, v12) Oleg Nesterov
@ 2010-10-05 18:30 ` Pedro Alves
2010-10-05 18:35 ` Pedro Alves
2010-10-06 17:23 ` Oleg Nesterov
0 siblings, 2 replies; 10+ messages in thread
From: Pedro Alves @ 2010-10-05 18:30 UTC (permalink / raw)
To: archer; +Cc: Oleg Nesterov, utrace-devel
On Tuesday 05 October 2010 18:27:29, Oleg Nesterov wrote:
> The more or less "typical" transcript is:
>
> [... snip ...]
> => s
This is already wrong.
"The stub must support @samp{vCont} if it reports support for
multiprocess extensions (@pxref{multiprocess extensions})."
The stub must also support vCont for non-stop, though I'll give you
that it doesn't appear to be mentioned in the manual, and that
gdb could be more noisy about this.
Look at remote.c:remote_resume, and you'll see that gdb does not
wait for the "OK" after 'c'/'s'/'S'/'C' in non-stop mode.
You're getting "lucky", because when gdb processes the OK you're
sending it, gdb is interpreting that as an 'O' stop reply, but
since 'K' is an uneven number of characters, remote_console_output
happens to just bail out silently.
Now, given this, I won't be surprised if you're seeing races
with ->s, <-OK, ->vCont sequences, as GDB may well be thinking
that the "OK" is a reply to the vCont.
> So, I strongly believe gdb is buggy and should be fixed.
Fix your stub to implement vCont;s/c(/S/C).
--
Pedro Alves
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-05 18:30 ` Pedro Alves
@ 2010-10-05 18:35 ` Pedro Alves
2010-10-06 17:23 ` Oleg Nesterov
1 sibling, 0 replies; 10+ messages in thread
From: Pedro Alves @ 2010-10-05 18:35 UTC (permalink / raw)
To: archer; +Cc: Oleg Nesterov, utrace-devel
On Tuesday 05 October 2010 19:30:38, Pedro Alves wrote:
> Now, given this, I won't be surprised if you're seeing races
> with ->s, <-OK, ->vCont sequences, as GDB may well be thinking
> that the "OK" is a reply to the vCont.
>
I meant ->s, <-OK, ->vStopped sequences.
--
Pedro Alves
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-05 18:30 ` Pedro Alves
2010-10-05 18:35 ` Pedro Alves
@ 2010-10-06 17:23 ` Oleg Nesterov
2010-10-06 18:32 ` Pedro Alves
1 sibling, 1 reply; 10+ messages in thread
From: Oleg Nesterov @ 2010-10-06 17:23 UTC (permalink / raw)
To: Pedro Alves; +Cc: archer, utrace-devel
On 10/05, Pedro Alves wrote:
>
(reordered)
> On Tuesday 05 October 2010 18:27:29, Oleg Nesterov wrote:
>
> > So, I strongly believe gdb is buggy and should be fixed.
>
> Fix your stub to implement vCont;s/c(/S/C).
First of all, I confirm that when I added the (incomplete right
now) support for vCont;s the problem goes away, gdb never forgets
to send the necessary vStopped to consume all stop-reply packets.
Thanks Pedro.
> > The more or less "typical" transcript is:
> >
> > [... snip ...]
> > => s
>
> This is already wrong.
>
> "The stub must support @samp{vCont} if it reports support for
> multiprocess extensions (@pxref{multiprocess extensions})."
Cough. Previously I was told here (on archer@sourceware.org) that
Hc + s/c is enough and I shouldn't worry about vCont;s/c ;)
Currently ugdb only supports vCont;t because otherwise there is
obviously no way to stop all threads.
> The stub must also support vCont for non-stop, though I'll give you
> that it doesn't appear to be mentioned in the manual,
Yes, the manual doesn't explain this. Quite contrary, the decsription
of 'vCont?' definitely looks as if the stub is not obliged to implement
all vCont commands.
And, if the stub must support vCont for non-stop, then why gdb
doesn't complain after 'vCont?' but falls back to '$s' ?
> Look at remote.c:remote_resume, and you'll see that gdb does not
> wait for the "OK" after 'c'/'s'/'S'/'C' in non-stop mode.
Then gdbserver should be fixed? It does send "OK" in response to '$s',
that is why ugdb does this.
And what should be replied back to '$s', nothing? Very strange.
But seems to work... And yes, this explains the hang, gdb thinks
that this "OK" is connected to vStopped.
Again, the documentation is very confusing. Looking at
remote_resume()->remote_vcont_resume()->getpkt() I think that
vCont;s needs "OK". Looking at "D.3 Stop Reply Packets" in
gdb.info I do not see any difference between `s' and `vCont'.
So. I still belive that something is wrong with gdb/gdbserever
but I don't care.
In any case ugdb should fully support vCont, hopefully I'll finish
this tomorrow. Could you answer a couple of questions?
1. Say, $vCont;s or $vCont;s:p-1.-1
I assume, this should ignore the running threads, correct?
IOW, iiuc this 's' applies to all threads which we already
reported as stopped.
2. Say, $vCont;c:pPID.TID;s:p-1.-1
Can I assume that gdb can never send this request as
$vCont;s:p-1.-1;c:pPID.TID ?
If yes, then the implementation will be much simpler, I can
add something like gencounters to ugdb_thread/process. Otherwise
this needs more complications to figure out what should be done
with each tracee.
Thanks,
Oleg.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-06 17:23 ` Oleg Nesterov
@ 2010-10-06 18:32 ` Pedro Alves
2010-10-07 23:03 ` Oleg Nesterov
0 siblings, 1 reply; 10+ messages in thread
From: Pedro Alves @ 2010-10-06 18:32 UTC (permalink / raw)
To: Oleg Nesterov; +Cc: archer, utrace-devel
On Wednesday 06 October 2010 18:19:53, Oleg Nesterov wrote:
> On 10/05, Pedro Alves wrote:
> > "The stub must support @samp{vCont} if it reports support for
> > multiprocess extensions (@pxref{multiprocess extensions})."
>
> Cough. Previously I was told here (on archer@sourceware.org) that
> Hc + s/c is enough and I shouldn't worry about vCont;s/c ;)
vCont was introduced because with only 'Hc', 's' and 'c', there's
no way to distinguish "step a thread and resume all others" vs "step
a thread and leave others stopped" (scheduler-locking, in gdb lingo).
This was added way before non-stop was added, back in 2002/2003,
I believe. vCont;t was added much later, when non-stop was
introduced.
> > The stub must also support vCont for non-stop, though I'll give you
> > that it doesn't appear to be mentioned in the manual,
>
> Yes, the manual doesn't explain this. Quite contrary, the decsription
> of 'vCont?' definitely looks as if the stub is not obliged to implement
> all vCont commands.
>
> And, if the stub must support vCont for non-stop, then why gdb
> doesn't complain after 'vCont?' but falls back to '$s' ?
Because nobody took the trouble to made it complain. As I said,
I'll give you that gdb could be noisier about that...
> > Look at remote.c:remote_resume, and you'll see that gdb does not
> > wait for the "OK" after 'c'/'s'/'S'/'C' in non-stop mode.
>
> Then gdbserver should be fixed? It does send "OK" in response to '$s',
> that is why ugdb does this.
Think of it as "undefined behavior". It could be made to
error out instead, if somebody cared. Not sure how you got gdb to
send gdbserver 's' or 'c' (well, unless you used
"set remote verbose-resume-packet off", or started gdbserver
with --disable-packet=vCont).
> Again, the documentation is very confusing. Looking at
> remote_resume()->remote_vcont_resume()->getpkt() I think that
> vCont;s needs "OK". Looking at "D.3 Stop Reply Packets" in
> gdb.info I do not see any difference between `s' and `vCont'.
Yeah. It's the problem that those that are very familiar with
the thing get to write docs for it, so may have missed spelling
out things that were obvious to them.
It goes without saying, but ... patches to improve the docs are
always welcome.
> In any case ugdb should fully support vCont, hopefully I'll finish
> this tomorrow. Could you answer a couple of questions?
>
> 1. Say, $vCont;s or $vCont;s:p-1.-1
>
> I assume, this should ignore the running threads, correct?
> IOW, iiuc this 's' applies to all threads which we already
> reported as stopped.
Yes.
>
> 2. Say, $vCont;c:pPID.TID;s:p-1.-1
This would be effectively
$vCont;c:pPID.TID;s
>
> Can I assume that gdb can never send this request as
>
> $vCont;s:p-1.-1;c:pPID.TID ?
>
> If yes, then the implementation will be much simpler, I can
> add something like gencounters to ugdb_thread/process. Otherwise
> this needs more complications to figure out what should be done
> with each tracee.
All GDB currently sends is in gdb/remote.c:remote_vcont_resume.
All vCont packets GDB sends today have the actions ordered
from more specific to less specific --- the most complicated
is something like "vCont;s:pPID.TID;c" (step PID.TID, continue
all others). It will probably make sense to maintain that
ordering, if we ever make a single vCont contain more
actions.
--
Pedro Alves
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-06 18:32 ` Pedro Alves
@ 2010-10-07 23:03 ` Oleg Nesterov
2010-10-08 0:03 ` Pedro Alves
0 siblings, 1 reply; 10+ messages in thread
From: Oleg Nesterov @ 2010-10-07 23:03 UTC (permalink / raw)
To: Pedro Alves; +Cc: archer, utrace-devel
On 10/06, Pedro Alves wrote:
>
> On Wednesday 06 October 2010 18:19:53, Oleg Nesterov wrote:
> >
> > Cough. Previously I was told here (on archer@sourceware.org) that
> > Hc + s/c is enough and I shouldn't worry about vCont;s/c ;)
>
> vCont was introduced because with only 'Hc', 's' and 'c', there's
> no way to distinguish "step a thread and resume all others" vs "step
> a thread and leave others stopped" (scheduler-locking, in gdb lingo).
Hmm. Not sure I understand this... gdb could issue a series of Hc+c
after s to do "step a thread and resume all others".
But this doesn't matter. Obviously vCont is better and more handy.
> Think of it as "undefined behavior". It could be made to
> error out instead, if somebody cared. Not sure how you got gdb to
> send gdbserver 's' or 'c'
I did $ gdb `which gdb` `pidof gdb` to change its behaviour ;)
> (well, unless you used
> "set remote verbose-resume-packet off", or started gdbserver
> with --disable-packet=vCont).
Ah, I'd wish I knew this before. Damn, I recall I saw these
disable_packet_xxx code in gdbserver sources, but forgot.
> > 1. Say, $vCont;s or $vCont;s:p-1.-1
> >
> > I assume, this should ignore the running threads, correct?
> > IOW, iiuc this 's' applies to all threads which we already
> > reported as stopped.
>
> Yes.
>
> >
> > 2. Say, $vCont;c:pPID.TID;s:p-1.-1
>
> This would be effectively
>
> $vCont;c:pPID.TID;s
>
> >
> > Can I assume that gdb can never send this request as
> >
> > $vCont;s:p-1.-1;c:pPID.TID ?
> >
> > If yes, then the implementation will be much simpler, I can
> > add something like gencounters to ugdb_thread/process. Otherwise
> > this needs more complications to figure out what should be done
> > with each tracee.
>
> All GDB currently sends is in gdb/remote.c:remote_vcont_resume.
> All vCont packets GDB sends today have the actions ordered
> from more specific to less specific
Great.
Pedro, thanks a lot.
Oleg.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-07 23:03 ` Oleg Nesterov
@ 2010-10-08 0:03 ` Pedro Alves
2010-10-08 0:23 ` Oleg Nesterov
0 siblings, 1 reply; 10+ messages in thread
From: Pedro Alves @ 2010-10-08 0:03 UTC (permalink / raw)
To: Oleg Nesterov; +Cc: archer, utrace-devel
On Thursday 07 October 2010 23:59:22, Oleg Nesterov wrote:
> Hmm. Not sure I understand this... gdb could issue a series of Hc+c
> after s to do "step a thread and resume all others".
>
> But this doesn't matter. Obviously vCont is better and more handy.
Not in all-stop mode. GDB can not send any other command to the
stub until the stub returns a stop reply to the first 's'. Remember,
there's no vStopped+notifications in the all-stop mode protocol.
--
Pedro Alves
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: BUG: gdb && notification packets (Was: gdbstub initial code, v12)
2010-10-08 0:03 ` Pedro Alves
@ 2010-10-08 0:23 ` Oleg Nesterov
0 siblings, 0 replies; 10+ messages in thread
From: Oleg Nesterov @ 2010-10-08 0:23 UTC (permalink / raw)
To: Pedro Alves; +Cc: archer, utrace-devel
On 10/08, Pedro Alves wrote:
>
> On Thursday 07 October 2010 23:59:22, Oleg Nesterov wrote:
> > Hmm. Not sure I understand this... gdb could issue a series of Hc+c
> > after s to do "step a thread and resume all others".
> >
> > But this doesn't matter. Obviously vCont is better and more handy.
>
> Not in all-stop mode.
Ah indeed. I missed you mentioned "This was added way before non-stop"
later.
Oleg.
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2010-10-08 0:23 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-09-30 18:27 gdbstub initial code, v12 Oleg Nesterov
2010-10-04 18:14 ` Oleg Nesterov
2010-10-05 17:31 ` BUG: gdb && notification packets (Was: gdbstub initial code, v12) Oleg Nesterov
2010-10-05 18:30 ` Pedro Alves
2010-10-05 18:35 ` Pedro Alves
2010-10-06 17:23 ` Oleg Nesterov
2010-10-06 18:32 ` Pedro Alves
2010-10-07 23:03 ` Oleg Nesterov
2010-10-08 0:03 ` Pedro Alves
2010-10-08 0:23 ` Oleg Nesterov
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