static void
i386_linux_resume (ptid_t ptid, int step, enum target_signal signal)
{
int pid = PIDGET (ptid);
int request = PTRACE_CONT;
if (pid == -1)
/* Resume all threads. */
/* I think this only gets used in the non-threaded case, where "resume
all threads" and "resume inferior_ptid" are the same. */
pid = PIDGET (inferior_ptid);
if (step)
{
CORE_ADDR pc = read_pc_pid (pid_to_ptid (pid));
gdb_byte buf[LINUX_SYSCALL_LEN];
request = PTRACE_SINGLESTEP;
/* Returning from a signal trampoline is done by calling a
special system call (sigreturn or rt_sigreturn, see
i386-linux-tdep.c for more information). This system call
restores the registers that were saved when the signal was
raised, including %eflags. That means that single-stepping
won't work. Instead, we'll have to modify the signal context
that's about to be restored, and set the trace flag there. */
/* First check if PC is at a system call. */
if (deprecated_read_memory_nobpt (pc, buf, LINUX_SYSCALL_LEN) == 0
&& memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0)
{
int syscall = read_register_pid (LINUX_SYSCALL_REGNUM,
pid_to_ptid (pid));
/* Then check the system call number. */
if (syscall == SYS_sigreturn || syscall == SYS_rt_sigreturn)
{
CORE_ADDR sp = read_register (I386_ESP_REGNUM);
CORE_ADDR addr = sp;
unsigned long int eflags;
if (syscall == SYS_rt_sigreturn)
addr = read_memory_integer (sp + 8, 4) + 20;
/* Set the trace flag in the context that's about to be
restored. */
addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET;
read_memory (addr, (gdb_byte *) &eflags, 4);
eflags |= 0x0100;
write_memory (addr, (gdb_byte *) &eflags, 4);
}
}
}
if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1)
perror_with_name (("ptrace"));
}
/* Generic prepare_to_proceed(). This one should be suitable for most
targets that support threads. */
int
generic_prepare_to_proceed (int select_it)
{
ptid_t wait_ptid;
struct target_waitstatus wait_status;
/* Get the last target status returned by target_wait(). */
get_last_target_status (&wait_ptid, &wait_status);
/* Make sure we were stopped either at a breakpoint, or because
of a Ctrl-C. */
if (wait_status.kind != TARGET_WAITKIND_STOPPED
|| (wait_status.value.sig != TARGET_SIGNAL_TRAP &&
wait_status.value.sig != TARGET_SIGNAL_INT))
{
return 0;
}
if (!ptid_equal (wait_ptid, minus_one_ptid)
&& !ptid_equal (inferior_ptid, wait_ptid))
{
/* Switched over from WAIT_PID. */
CORE_ADDR wait_pc = read_pc_pid (wait_ptid);
if (wait_pc != read_pc ())
{
if (select_it)
{
/* Switch back to WAIT_PID thread. */
inferior_ptid = wait_ptid;
/* FIXME: This stuff came from switch_to_thread() in
thread.c (which should probably be a public function). */
flush_cached_frames ();
registers_changed ();
stop_pc = wait_pc;
select_frame (get_current_frame ());
}
/* We return 1 to indicate that there is a breakpoint here,
so we need to step over it before continuing to avoid
hitting it straight away. */
if (breakpoint_here_p (wait_pc))
{
return 1;
}
}
}
return 0;
}
static void
check_event (ptid_t ptid)
{
td_event_msg_t msg;
td_thrinfo_t ti;
td_err_e err;
CORE_ADDR stop_pc;
int loop = 0;
/* Bail out early if we're not at a thread event breakpoint. */
stop_pc = read_pc_pid (ptid) - DECR_PC_AFTER_BREAK;
if (stop_pc != td_create_bp_addr && stop_pc != td_death_bp_addr)
return;
loop = 1;
do
{
err = td_ta_event_getmsg_p (thread_agent, &msg);
if (err != TD_OK)
{
if (err == TD_NOMSG)
return;
error ("Cannot get thread event message: %s",
thread_db_err_str (err));
}
err = td_thr_get_info_p ((void *)(uintptr_t)msg.th_p, &ti);
if (err != TD_OK)
error ("Cannot get thread info: %s", thread_db_err_str (err));
ptid = BUILD_THREAD (ti.ti_tid, GET_PID (ptid));
switch (msg.event)
{
case TD_CREATE:
/* We may already know about this thread, for instance when the
user has issued the `info threads' command before the SIGTRAP
for hitting the thread creation breakpoint was reported. */
attach_thread (ptid, (void *)(uintptr_t)msg.th_p, &ti, 1);
break;
case TD_DEATH:
if (!in_thread_list (ptid))
error ("Spurious thread death event.");
detach_thread (ptid, 1);
break;
default:
error ("Spurious thread event.");
}
}
while (loop);
}
