prctl - 在操作過程

內容簡介

#include <sys/prctl.h>

int prctl(int option**, unsigned long** arg2**, unsigned long** arg3 , unsigned long arg4**, unsigned long** arg5**);**

描述

prctl () is called with a first argument describing what to do (with values defined in < *linux/prctl.h* >), and further parameters with a significance depending on the first one. The first argument can be:

標籤

描述

PR_SET_PDEATHSIG

 

(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().

PR_GET_PDEATHSIG

 

(since Linux 2.3.15) Read the current value of the parent process death signal into the (int *) arg2.

PR_SET_DUMPABLE

 

(Since Linux 2.4) Set the state of the flag determining whether core dumps are produced for this process upon delivery of a signal whose default behaviour is to produce a core dump. (Normally this flag is set for a process by default, but it is cleared when a set-user-ID or set-group-ID program is executed and also by various system calls that manipulate process UIDs and GIDs). In kernels up to and including 2.6.12,arg2 must be either 0 (process is not dumpable) or 1 (process is dumpable). Since kernel 2.6.13, the value 2 is also permitted; this causes any binary which normally would not be dumped to be dumped readable by root only. (See also the description of*/proc/sys/fs/suid_dumpable* in proc(5).)

PR_GET_DUMPABLE

 

(Since Linux 2.4) Return (as the function result) the current state of the calling process’s dumpable flag.

PR_SET_KEEPCAPS

 

Set the state of the process’s "keep capabilities" flag, which determines whether the process’s effective and permitted capability sets are cleared when a change is made to the process’s user IDs such that the process’s real UID, effective UID, and saved set-user-ID all 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).

PR_GET_KEEPCAPS

 

Return (as the function result) the current state of the calling process’s "keep capabilities" flag.

返回值

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.

錯誤

標籤

描述

EINVAL

The value of option is not recognized, or it isPR_SET_PDEATHSIG and arg2 is not zero or a signal number.

遵循於

This call is Linux-specific. IRIX has a  prctl () system call (also introduced in Linux 2.1.44 as irix_prctl on the MIPS architecture), with prototype

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 maximum stack size, etc.

可用性

The  prctl () system call was introduced in Linux 2.1.57.

另請參閱

• signal (2)