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Name

kvm_nextproc, kvm_getproc, kvm_setproc - read system process structures

Synopsis


#include <kvm.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/proc.h>

struct proc *kvm_getproc(kvm_t *kd, int pid);

struct proc *kvm_nextproc(kvm_t *kd);

int kvm_setproc (kvm_t *kd);

MT-Level

Unsafe

Description

kvm_nextproc() may be used to sequentially read all of the system process structures from the kernel identified by kd (see kvm_open(3K) ). Each call to kvm_nextproc() returns a pointer to the static memory area that contains a copy of the next valid process table entry. There is no guarantee that the data will remain valid across calls to kvm_nextproc(), kvm_setproc(), or kvm_getproc(). Therefore, if the process structure must be saved, it should be copied to non-volatile storage.

For performance reasons, many implementations will cache a set of system process structures. Since the system state is liable to change between calls to kvm_nextproc(), and since the cache may contain obsolete information, there is no guarantee that every process structure returned refers to an active process, nor is it certain that all processes will be reported.

kvm_setproc() rewinds the process list, enabling kvm_nextproc() to rescan from the beginning of the system process table. kvm_setproc() will always flush the process structure cache, allowing an application to re-scan the process table of a running system.

kvm_getproc() locates the proc structure of the process specified by pid and returns a pointer to it. kvm_getproc() does not interact with the process table pointer manipulated by kvm_nextproc(), however, the restrictions regarding the validity of the data still apply.

Return Values

On success, kvm_nextproc() returns a pointer to a copy of the next valid process table entry. On failure, it returns NULL .

On success, kvm_getproc() returns a pointer to the proc structure of the process specified by pid. On failure, it returns NULL .

kvm_setproc() returns:

  1. on success.
    -1
    on failure.

    See Also

    kvm_getu(3K) , kvm_open(3K) , kvm_read(3K)

    Table of Contents