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:
|(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 process 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 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).)|
|(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 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).|
|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 optionvalues return 0 on success. On error, -1 is returned, and errno is set appropriately.
|EINVAL||The value of option is not recognized, or it isPR_SET_PDEATHSIG and arg2 is not zero or a signal number.|
遵循于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.