This matches the behaviour of other Unix-like systems that have SIGINFO
and causes less harm to processes that do not install handlers for this
signal, making the keyboard status character non-fatal for them.
This is implemented with the assumption that SIGINFO is defined
to be equivalent to SIGPWR; still, there is no reason for PWR to
result in termination of the signal recipient anyway — it does not
indicate there is a fatal problem with the recipient's execution
context (like e.g. FPE/ILL do), and we have TERM/KILL for explicit
termination requests.
To put it another way:
The only scenario where system behaviour actually changes is when the
signal recipient has default disposition for SIGPWR. If a process
chose to interpret a SIGPWR as an incentive to cleanly terminate, it
would supply its own handler — and this commit does not affect processes
with non-default handlers.
Signed-off-by: Arseny Maslennikov <ar@xxxxxxxxx>
---
include/linux/signal.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 05bacd2ab..dc31da8fc 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -369,7 +369,7 @@ extern bool unhandled_signal(struct task_struct *tsk, int sig);
* | SIGSYS/SIGUNUSED | coredump |
* | SIGSTKFLT | terminate |
* | SIGWINCH | ignore |
- * | SIGPWR | terminate |
+ * | SIGPWR | ignore |
* | SIGRTMIN-SIGRTMAX | terminate |
* +--------------------+------------------+
* | non-POSIX signal | default action |
@@ -420,7 +420,8 @@ extern bool unhandled_signal(struct task_struct *tsk, int sig);
#define SIG_KERNEL_IGNORE_MASK (\
rt_sigmask(SIGCONT) | rt_sigmask(SIGCHLD) | \
- rt_sigmask(SIGWINCH) | rt_sigmask(SIGURG) )
+ rt_sigmask(SIGWINCH) | rt_sigmask(SIGURG) | \
+ rt_sigmask(SIGINFO) )
#define SIG_SPECIFIC_SICODES_MASK (\
rt_sigmask(SIGILL) | rt_sigmask(SIGFPE) | \
--
2.26.2
