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Name

sigsend, sigsendset - send a signal to a process or a group of processes

Synopsis


#include <signal.h>

int sigsend(idtype_t idtype, id_t id, int sig);

int sigsendset(procset_t *psp, int sig);

Description

sigsend() 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 0 or one of the values listed in signal(5) . If sig is 0 (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.

The real or effective user ID of the sending process must match the real or saved 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_CID , sig is sent to any process with scheduler class ID id (see priocntl(2) ).

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: 


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 ID s 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 function 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

Return Values

On success, sigsend() returns 0. On failure, it returns -1 and sets errno to indicate the error.

Errors

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.
EINVAL
sig is SIGKILL , idtype is P_PID and id is 1 (proc1).
EPERM
The effective user of the calling process is not super-user, and its real or effective user ID 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 to an illegal address.

See Also

kill(1) , getpid(2) , kill(2) , priocntl(2) , signal(3C) , signal(5)

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