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man pages section 3: Extended Library Functions, Volume 2

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Updated: Thursday, June 13, 2019
 
 

kvm_nextproc(3KVM)

Name

kvm_nextproc, kvm_getproc, kvm_setproc - read system process structures

Synopsis

cc [ flag… ] file–lkvm [ library…]
#include <kvm.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/proc.h>

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

Description

The kvm_nextproc() function reads sequentially all of the system process structures from the kernel identified by kd (see kvm_open(3KVM)). 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(). 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.

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

The kvm_getproc() function locates the proc structure of the process specified by pid and returns a pointer to it. Although this function does not interact with the process table pointer manipulated by kvm_nextproc(), 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.

The kvm_setproc() function returns 0 on success and −1 on failure.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
MT-Level
Unsafe

See Also

kvm_getu(3KVM), kvm_kread(3KVM), kvm_open(3KVM), attributes(7)