9.74 send_signal ¶

int send_signal(int pid, int signal);

This syscall sends the passed signal to the passed PID.

Group sending is not supported, but can easily be implemented in userland with process information. sysconf.

Only processes sharing the same UID or EUID as the caller’s EUID can be signaled. The MAC_CAP_SIGNALALL capability overrides this check.

It returns 0 on success and -1 on failure, with the following errno:

ESRCH

pid is not a valid target for sending.

EPERM

The caller does not have permissions to signal pid.

EINVAL

signal is not a valid signal.