sigsend(2)sigsend(2)NAME
sigsend, sigsendset - send a signal to a process or a group of processes
SYNOPSIS
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/procset.h>
int sigsend(idtype_t idtype, id_t id, int sig);
int sigsendset(procset_t *psp, int sig);
DESCRIPTIONsigsend sends a signal to the process or group of processes specified by
id and idtype. The signal to be sent is specified by sig and is either
zero or one of the values listed in signal(5). If sig is zero (the null
signal), error checking is performed but no signal is actually sent.
This value can be used to check the validity of id and idtype.
In order to send the signal to the target process (pid), the sending
process must have permission to do so, subject to the following ownership
restrictions:
The real or effective user ID of the sending process must match the
real or saved [from exec(2)] user ID of the receiving process,
unless the effective user ID of the sending process is super-user,
or sig is SIGCONT and the sending process has the same session ID as
the receiving process.
If idtype is P_PID, sig is sent to the process with process ID id.
If idtype is P_PGID, sig is sent to any process with process group ID id.
If idtype is P_SID, sig is sent to any process with session ID id.
If idtype is P_UID, sig is sent to any process with effective user ID id.
If idtype is P_GID, sig is sent to any process with effective group ID
id.
If idtype is P_ALL, sig is sent to all processes and id is ignored.
If id is P_MYID, the value of id is taken from the calling process.
The process with a process ID of 0 is always excluded. The process with
a process ID of 1 is excluded unless idtype is equal to P_PID.
sigsendset provides an alternate interface for sending signals to sets of
processes. This function sends signals to the set of processes specified
by psp. psp is a pointer to a structure of type procset_t, defined in
sys/procset.h>, which includes the following members:
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sigsend(2)sigsend(2)
idop_t p_op;
idtype_t p_lidtype;
id_t p_lid;
idtype_t p_ridtype;
id_t p_rid;
p_lidtype and p_lid specify the ID type and ID of one (``left'') set of
processes; p_ridtype and p_rid specify the ID type and ID of a second
(``right'') set of processes. ID types and IDs are specified just as for
the idtype and id arguments to sigsend. p_op specifies the operation to
be performed on the two sets of processes to get the set of processes the
system call is to apply to. The valid values for p_op and the processes
they specify are:
POP_DIFF set difference: processes in left set and not in right set
POP_AND set intersection: processes in both left and right sets
POP_OR set union: processes in either left or right set or both
POP_XOR set exclusive-or: processes in left or right set but not in
both
sigsend and sigsendset fail if one or more of the following are true:
EINVAL sig is not a valid signal number.
EINVAL idtype is not a valid idtype field.
EPERM sig is SIGKILL, idtype is P_PID and id is 1 (proc1).
EPERM The calling process does not have super-user privilege,
the real or effective user ID of the sending process does
not match the real or effective user ID of the receiving
process, and the calling process is not sending SIGCONT to
a process that shares the same session.
ESRCH No process can be found corresponding to that specified by
id and idtype.
In addition, sigsendset fails if:
EFAULT psp points outside the process's allocated address space.
SEE ALSOkill(1), getpid(2), getpgrp(2), kill(2), setpid(2), signal(2), signal(5)DIAGNOSTICS
On success, sigsend returns zero. On failure, it returns -1 and sets
errno to indicate the error.
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