Re: [PATCH v3 06/10] run-command: add clean_on_exit_handler
From: Johannes Sixt <hidden>
Date: 2016-07-30 09:50:28
Am 30.07.2016 um 01:37 schrieb larsxschneider@gmail.com:
quoted hunk ↗ jump to hunk
Some commands might need to perform cleanup tasks on exit. Let's give them an interface for doing this. Signed-off-by: Lars Schneider <redacted> --- run-command.c | 12 ++++++++---- run-command.h | 1 + 2 files changed, 9 insertions(+), 4 deletions(-)diff --git a/run-command.c b/run-command.c index 33bc63a..197b534 100644 --- a/run-command.c +++ b/run-command.c@@ -21,6 +21,7 @@ void child_process_clear(struct child_process *child) struct child_to_clean { pid_t pid; + void (*clean_on_exit_handler)(pid_t); struct child_to_clean *next; }; static struct child_to_clean *children_to_clean;@@ -30,6 +31,8 @@ static void cleanup_children(int sig, int in_signal) { while (children_to_clean) { struct child_to_clean *p = children_to_clean; + if (p->clean_on_exit_handler) + p->clean_on_exit_handler(p->pid);
This summons demons. cleanup_children() is invoked from a signal handler. In this case, it can call only async-signal-safe functions. It does not look like the handler that you are going to install later will take note of this caveat!
children_to_clean = p->next; kill(p->pid, sig); if (!in_signal)
The condition that we see here in the context protects free(p) (which is not async-signal-safe). Perhaps the invocation of the new callback should be skipped in the same manner when this is called from a signal handler? 507d7804 (pager: don't use unsafe functions in signal handlers) may be worth a look. -- Hannes