FreeChainXenon/binutils-gdb
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

gdb: Reorganize linux_nat_filter_event

Browse source 
Reorganize linux-nat.c:linux_nat_filter_event such that all the
handling for events for LWPs not in the LWP list is together.  This
helps make a following patch clearer.  The comments and debug messages
have also been tweaked - the end goal is to have them synchronized
with the gdbserver counterpart.

Change-Id: I8586d8dcd76d8bd3795145e3056fc660e3b2cd22
This commit is contained in:
Pedro Alves 2022-02-21 20:07:20 +00:00
parent b7b1008c0b
commit 1abeb1e90d
1 changed files with 41 additions and 36 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

77
gdb/linux-nat.c
View file

@ -2776,46 +2776,51 @@ linux_nat_filter_event (int lwpid, int status)
lp = find_lwp_pid (ptid_t (lwpid));
/* Check for stop events reported by a process we didn't already
know about - anything not already in our LWP list.
If we're expecting to receive stopped processes after
fork, vfork, and clone events, then we'll just add the
new one to our list and go back to waiting for the event
to be reported - the stopped process might be returned
from waitpid before or after the event is.
But note the case of a non-leader thread exec'ing after the
leader having exited, and gone from our lists. The non-leader
thread changes its tid to the tgid. */
if (WIFSTOPPED (status) && lp == NULL
&& (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
/* Check for events reported by anything not in our LWP list. */
if (lp == nullptr)
{
/* A multi-thread exec after we had seen the leader exiting. */
linux_nat_debug_printf ("Re-adding thread group leader LWP %d.", lwpid);
if (WIFSTOPPED (status))
{
if (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC)
{
/* A non-leader thread exec'ed after we've seen the
leader zombie, and removed it from our lists (in
check_zombie_leaders). The non-leader thread changes
its tid to the tgid. */
linux_nat_debug_printf
("Re-adding thread group leader LWP %d after exec.",
lwpid);
lp = add_lwp (ptid_t (lwpid, lwpid));
lp->stopped = 1;
lp->resumed = 1;
add_thread (linux_target, lp->ptid);
lp = add_lwp (ptid_t (lwpid, lwpid));
lp->stopped = 1;
lp->resumed = 1;
add_thread (linux_target, lp->ptid);
}
else
{
/* A process we are controlling has forked and the new
child's stop was reported to us by the kernel. Save
its PID and go back to waiting for the fork event to
be reported - the stopped process might be returned
from waitpid before or after the fork event is. */
linux_nat_debug_printf
("Saving LWP %d status %s in stopped_pids list",
lwpid, status_to_str (status).c_str ());
add_to_pid_list (&stopped_pids, lwpid, status);
}
}
else
{
/* Don't report an event for the exit of an LWP not in our
list, i.e. not part of any inferior we're debugging.
This can happen if we detach from a program we originally
forked and then it exits. */
}
if (lp == nullptr)
return;
}
if (WIFSTOPPED (status) && !lp)
{
linux_nat_debug_printf ("saving LWP %ld status %s in stopped_pids list",
(long) lwpid, status_to_str (status).c_str ());
add_to_pid_list (&stopped_pids, lwpid, status);
return;
}
/* Make sure we don't report an event for the exit of an LWP not in
our list, i.e. not part of the current process. This can happen
if we detach from a program we originally forked and then it
exits. */
if (!WIFSTOPPED (status) && !lp)
return;
/* This LWP is stopped now. (And if dead, this prevents it from
ever being continued.) */
lp->stopped = 1;