Linux man pages : prctl (2)
PRCTL(2) Linux Programmer's Manual PRCTL(2)
prctl - operations on a process
int prctl(int option, unsigned long arg2, unsigned long arg3 , unsigned
long arg4, unsigned long arg5);
prctl is called with a first argument describing what to do (with val-
ues defined in <linux/prctl.h>), and further parameters with a signifi-
cance depending on the first one. The first argument can be:
(since Linux 2.1.57) Set the parent process death signal of the
current process to arg2 (either a signal value in the range
1..maxsig, or 0 to clear). This is the signal that the current
process will get when its parent dies. This value is cleared
upon a fork().
(since Linux 2.3.15) Read the current value of the parent pro-
cess death signal into the (int *) arg2.
(Since Linux 2.4) Set the state of the flag determining whether
core dumps are produced for this process upon delivery of a sig-
nal whose default behaviour is to produce a core dump. (Nor-
mally this flag is set for a process by default, but it is
cleared when a set-UID or set-GID program is executed and also
by various system calls that manipulate process UIDs and GIDs).
arg2 must be either 0 (process is not dumapable) or 1 (process
(Since Linux 2.4) Return (as the function result) the current
state of the calling process's dumpable flag.
Set the state of the process's "keep capabilities" flag, which
determines whether the process's effective and permitted capa-
bility sets are cleared when a change is made to the process's
user IDs such that all of the process's real, effective, and
saved set user IDs become non-zero when at least one of them
previously had the value 0. (By default, these credential sets
are cleared). arg2 must be either 0 (capabilities are cleared)
or 1 (capabilities are kept).
Return (as the function result) the current state of the calling
process's "keep capabilities" flag.
PR_GET_DUMPABLE and PR_GET_KEEPCAPS return 0 or 1 on success. All
other option values return 0 on success. On error, -1 is returned, and
errno is set appropriately.
EINVAL The value of option is not recognized, or it is PR_SET_PDEATHSIG
and arg2 is not zero or a signal number.
This call is Linux-specific. IRIX has a prctl system call (also intro-
duced in Linux 2.1.44 as irix_prctl on the MIPS architecture), with
ptrdiff_t prctl(int option, int arg2, int arg3);
and options to get the maximum number of processes per user, get the
maximum number of processors the calling process can use, find out
whether a specified process is currently blocked, get or set the maxi-
mum stack size, etc., etc.
The prctl() systemcall was introduced in Linux 2.1.57. There is no
prctl() library call as yet.
Linux 2.4.18 2002-06-27 PRCTL(2)