static int sigtrap_is_event (int status);
static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
+\f
+/* LWP accessors. */
+
+/* See nat/linux-nat.h. */
+
+ptid_t
+ptid_of_lwp (struct lwp_info *lwp)
+{
+ return lwp->ptid;
+}
+
+/* See nat/linux-nat.h. */
+
+int
+lwp_is_stopped (struct lwp_info *lwp)
+{
+ return lwp->stopped;
+}
+
+/* See nat/linux-nat.h. */
+
+enum target_stop_reason
+lwp_stop_reason (struct lwp_info *lwp)
+{
+ return lwp->stop_reason;
+}
+
\f
/* Trivial list manipulation functions to keep track of a list of
new stopped processes. */
return NULL;
}
-/* Call CALLBACK with its second argument set to DATA for every LWP in
- the list. If CALLBACK returns 1 for a particular LWP, return a
- pointer to the structure describing that LWP immediately.
- Otherwise return NULL. */
+/* See nat/linux-nat.h. */
struct lwp_info *
iterate_over_lwps (ptid_t filter,
- int (*callback) (struct lwp_info *, void *),
+ iterate_over_lwps_ftype callback,
void *data)
{
struct lwp_info *lp, *lpnext;
if (ptid_match (lp->ptid, filter))
{
- if ((*callback) (lp, data))
+ if ((*callback) (lp, data) != 0)
return lp;
}
}
struct lwp_info *lp;
int status;
ptid_t ptid;
- volatile struct gdb_exception ex;
/* Make sure we report all signals during attach. */
linux_nat_pass_signals (ops, 0, NULL);
- TRY_CATCH (ex, RETURN_MASK_ERROR)
+ TRY
{
linux_ops->to_attach (ops, args, from_tty);
}
- if (ex.reason < 0)
+ CATCH (ex, RETURN_MASK_ERROR)
{
pid_t pid = parse_pid_to_attach (args);
struct buffer buffer;
else
throw_error (ex.error, "%s", message);
}
+ END_CATCH
/* The ptrace base target adds the main thread with (pid,0,0)
format. Decorate it with lwp info. */
single-step it. If SIGNAL is nonzero, give it that signal. */
static void
-linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
+linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
+ enum gdb_signal signo)
{
lp->step = step;
if (linux_nat_prepare_to_resume != NULL)
linux_nat_prepare_to_resume (lp);
linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
- lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
+
+ /* Successfully resumed. Clear state that no longer makes sense,
+ and mark the LWP as running. Must not do this before resuming
+ otherwise if that fails other code will be confused. E.g., we'd
+ later try to stop the LWP and hang forever waiting for a stop
+ status. Note that we must not throw after this is cleared,
+ otherwise handle_zombie_lwp_error would get confused. */
lp->stopped = 0;
+ lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
registers_changed_ptid (lp->ptid);
}
+/* Called when we try to resume a stopped LWP and that errors out. If
+ the LWP is no longer in ptrace-stopped state (meaning it's zombie,
+ or about to become), discard the error, clear any pending status
+ the LWP may have, and return true (we'll collect the exit status
+ soon enough). Otherwise, return false. */
+
+static int
+check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
+{
+ /* If we get an error after resuming the LWP successfully, we'd
+ confuse !T state for the LWP being gone. */
+ gdb_assert (lp->stopped);
+
+ /* We can't just check whether the LWP is in 'Z (Zombie)' state,
+ because even if ptrace failed with ESRCH, the tracee may be "not
+ yet fully dead", but already refusing ptrace requests. In that
+ case the tracee has 'R (Running)' state for a little bit
+ (observed in Linux 3.18). See also the note on ESRCH in the
+ ptrace(2) man page. Instead, check whether the LWP has any state
+ other than ptrace-stopped. */
+
+ /* Don't assume anything if /proc/PID/status can't be read. */
+ if (linux_proc_pid_is_trace_stopped_nowarn (ptid_get_lwp (lp->ptid)) == 0)
+ {
+ lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
+ lp->status = 0;
+ lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
+ return 1;
+ }
+ return 0;
+}
+
+/* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
+ disappears while we try to resume it. */
+
+static void
+linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
+{
+ TRY
+ {
+ linux_resume_one_lwp_throw (lp, step, signo);
+ }
+ CATCH (ex, RETURN_MASK_ERROR)
+ {
+ if (!check_ptrace_stopped_lwp_gone (lp))
+ throw_exception (ex);
+ }
+ END_CATCH
+}
+
/* Resume LP. */
static void
if (!lp->resumed)
return 0;
+ if (!lwp_status_pending_p (lp))
+ return 0;
+
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
|| lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
{
CORE_ADDR pc;
int discard = 0;
- gdb_assert (lp->status != 0);
-
pc = regcache_read_pc (regcache);
if (pc != lp->stop_pc)
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
return 0;
}
- return 1;
}
- return lwp_status_pending_p (lp);
+ return 1;
}
/* Return non-zero if LP isn't stopped. */
return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
}
-/* Select the Nth LWP that has had a SIGTRAP event. */
+/* Select the Nth LWP that has had an event. */
static int
select_event_lwp_callback (struct lwp_info *lp, void *data)
/* First see how many events we have. */
iterate_over_lwps (filter, count_events_callback, &num_events);
+ gdb_assert (num_events > 0);
/* Now randomly pick a LWP out of those that have had
events. */
{
struct regcache *regcache = get_thread_regcache (lp->ptid);
struct gdbarch *gdbarch = get_regcache_arch (regcache);
- CORE_ADDR pc = regcache_read_pc (regcache);
- /* Don't bother if there's a breakpoint at PC that we'd hit
- immediately, and we're not waiting for this LWP. */
- if (!ptid_match (lp->ptid, *wait_ptid_p))
+ TRY
{
- if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
- return 0;
- }
+ CORE_ADDR pc = regcache_read_pc (regcache);
+ int leave_stopped = 0;
- if (debug_linux_nat)
- fprintf_unfiltered (gdb_stdlog,
- "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
- target_pid_to_str (lp->ptid),
- paddress (gdbarch, pc),
- lp->step);
+ /* Don't bother if there's a breakpoint at PC that we'd hit
+ immediately, and we're not waiting for this LWP. */
+ if (!ptid_match (lp->ptid, *wait_ptid_p))
+ {
+ if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
+ leave_stopped = 1;
+ }
- linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
+ if (!leave_stopped)
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "RSRL: resuming stopped-resumed LWP %s at "
+ "%s: step=%d\n",
+ target_pid_to_str (lp->ptid),
+ paddress (gdbarch, pc),
+ lp->step);
+
+ linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
+ }
+ }
+ CATCH (ex, RETURN_MASK_ERROR)
+ {
+ if (!check_ptrace_stopped_lwp_gone (lp))
+ throw_exception (ex);
+ }
+ END_CATCH
}
return 0;
Unfortunately some Red Hat kernels include the shared pending
queue but not the ShdPnd status field. */
- if (strncmp (buffer, "SigPnd:\t", 8) == 0)
+ if (startswith (buffer, "SigPnd:\t"))
add_line_to_sigset (buffer + 8, pending);
- else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
+ else if (startswith (buffer, "ShdPnd:\t"))
add_line_to_sigset (buffer + 8, pending);
- else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
+ else if (startswith (buffer, "SigBlk:\t"))
add_line_to_sigset (buffer + 8, blocked);
- else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
+ else if (startswith (buffer, "SigIgn:\t"))
add_line_to_sigset (buffer + 8, ignored);
}
return 1;
}
+/* See nat/linux-nat.h. */
+
+ptid_t
+current_lwp_ptid (void)
+{
+ gdb_assert (ptid_lwp_p (inferior_ptid));
+ return inferior_ptid;
+}
+
/* Provide a prototype to silence -Wmissing-prototypes. */
extern initialize_file_ftype _initialize_linux_nat;
projects / deliverable / binutils-gdb.git / blobdiff