1:31 p.m.
When an ell main loop based process is spun off as a child
and the parent process dies due to a segfault, the child process
is still left running and needs to detect the segfault condition.
To address this need, add watch and signal handler for SIGSEGV.
---
ell/main.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/ell/main.c b/ell/main.c
index a479b74..712cfb7 100644
--- a/ell/main.c
+++ b/ell/main.c
@@ -619,6 +619,14 @@ static void sigterm_handler(void *user_data)
data->callback(SIGTERM, data->user_data);
}
+static void sigsegv_handler(void *user_data)
+{
+ struct signal_data *data = user_data;
+
+ if (data->callback)
+ data->callback(SIGSEGV, data->user_data);
+}
+
/**
* l_main_run_with_signal:
*
@@ -633,6 +641,7 @@ LIB_EXPORT int l_main_run_with_signal(l_main_signal_cb_t callback,
struct signal_data *data;
struct l_signal *sigint;
struct l_signal *sigterm;
+ struct l_signal *sigsegv;
int result;
data = l_new(struct signal_data, 1);
@@ -642,11 +651,13 @@ LIB_EXPORT int l_main_run_with_signal(l_main_signal_cb_t callback,
sigint = l_signal_create(SIGINT, sigint_handler, data, NULL);
sigterm = l_signal_create(SIGTERM, sigterm_handler, data, NULL);
+ sigsegv = l_signal_create(SIGSEGV, sigsegv_handler, data, NULL);
result = l_main_run();
l_signal_remove(sigint);
l_signal_remove(sigterm);
+ l_signal_remove(sigsegv);
l_free(data);
--
2.26.2
3:35 p.m.
Hi Inga,
On 1/25/21 4:31 PM, Inga Stotland wrote:
When an ell main loop based process is spun off as a child
and the parent process dies due to a segfault, the child process
is still left running and needs to detect the segfault condition.
To address this need, add watch and signal handler for SIGSEGV.
---
ell/main.c | 11 +++++++++++
1 file changed, 11 insertions(+)
Applied, thanks.
Regards,
-Denis
12:02 a.m.
Hi Inga,
When an ell main loop based process is spun off as a child
and the parent process dies due to a segfault, the child process
is still left running and needs to detect the segfault condition.
To address this need, add watch and signal handler for SIGSEGV.
---
ell/main.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/ell/main.c b/ell/main.c
index a479b74..712cfb7 100644
--- a/ell/main.c
+++ b/ell/main.c
@@ -619,6 +619,14 @@ static void sigterm_handler(void *user_data)
data->callback(SIGTERM, data->user_data);
}
+static void sigsegv_handler(void *user_data)
+{
+ struct signal_data *data = user_data;
+
+ if (data->callback)
+ data->callback(SIGSEGV, data->user_data);
+}
+
actually this is not enough. I never included SIGSEGV here for the simple reason since you
have to do a lot of work when that signal happens.
What we need to do is to add proper child spawning handling that does all the nasty signal
handling for you. Otherwise you are just about to create zombies. For now if you need
child handling, then add your own signal handler instead trying to overload
l_main_run_with_signal with it.
Regards
Marcel
2:46 p.m.
Hi Marcel,
On Tue, 2021-01-26 at 10:02 +0100, Marcel Holtmann wrote:
Hi Inga,
When an ell main loop based process is spun off as a child
and the parent process dies due to a segfault, the child process
is still left running and needs to detect the segfault condition.
To address this need, add watch and signal handler for SIGSEGV.
---
ell/main.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/ell/main.c b/ell/main.c
index a479b74..712cfb7 100644
--- a/ell/main.c
+++ b/ell/main.c
@@ -619,6 +619,14 @@ static void sigterm_handler(void *user_data)
data->callback(SIGTERM, data->user_data);
}
+static void sigsegv_handler(void *user_data)
+{
+ struct signal_data *data = user_data;
+
+ if (data->callback)
+ data->callback(SIGSEGV, data->user_data);
+}
+
actually this is not enough. I never included SIGSEGV here for the simple reason since you
have to do a lot of work when that signal happens.
What we need to do is to add proper child spawning handling that does all the nasty signal
handling for you. Otherwise you are just about to create zombies. For now if you need
child handling, then add your own signal handler instead trying to overload
l_main_run_with_signal with it.
I don't disagree that this is not enough.
However, this is the easiest way I could come up that allows a child to detect a parent
process crash.
Not very elegant as I had to add prctl() call to the child (but only in testing mode, so
should not be awful).
Do you have better suggestions on to how to catch a segfault originating in another
process without modifying ell?
Best regards,
Inga
8:53 a.m.
Hi Denis,
On Tue, 2021-01-26 at 10:02 +0100, Marcel Holtmann wrote:
Hi Inga,
When an ell main loop based process is spun off as a child
and the parent process dies due to a segfault, the child process
is still left running and needs to detect the segfault condition.
To address this need, add watch and signal handler for SIGSEGV.
---
ell/main.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/ell/main.c b/ell/main.c
index a479b74..712cfb7 100644
--- a/ell/main.c
+++ b/ell/main.c
@@ -619,6 +619,14 @@ static void sigterm_handler(void *user_data)
data->callback(SIGTERM, data->user_data);
}
+static void sigsegv_handler(void *user_data)
+{
+ struct signal_data *data = user_data;
+
+ if (data->callback)
+ data->callback(SIGSEGV, data->user_data);
+}
+
actually this is not enough. I never included SIGSEGV here for the simple reason since you
have to do a lot of work when that signal happens.
What we need to do is to add proper child spawning handling that does all the nasty signal
handling for you. Otherwise you are just about to create zombies. For now if you need
child handling, then add your own signal handler instead trying to overload
l_main_run_with_signal with it.
We may want to revert this commit. It's harmless, but adds extra code to ell.
There's a way to deal with the segfault situation across the processes without
involving ell (thank you Phil for the suggestion).
Sorry for the churn.
Best Regards,
Inga
559
days inactive
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4 comments
4 participants
participants (4)
-
Denis Kenzior -
Inga Stotland -
Marcel Holtmann -
Stotland, Inga