w_getpsent -- Get Process Information

SYNOPSIS

 #include <sys/ps.h>

 int w_getpsent(int processPos, struct w_psproc *bufferArea,
                size_t bufferLength);

DESCRIPTION

w_getpsent gets information about all processes for which the caller is authorized. The arguments to the w_getpsent function are:

processPos: is an integer that identifies the relative position of a process within the system, with a 0 representing the first process. You should call w_getpsent from within a loop. On the first call, pass a 0 as the processPos argument, and w_getpsent will return the position value of the next process that the calling process has access to. This value is then used as the processPos argument for the next call. Continue to loop until a 0 is returned.
bufferArea: is a pointer to a buffer area that is used to store information about the processes.
bufferLength: is the length in bytes of the buffer area.

The information about a process is stored in a w_psproc structure, which is declared in <sys/ps.h>. You may access the following elements of this structure to obtain process information:

unsigned int ps_state: process state
pid_t ps_pid: process identification
pid_t ps_ppid: process parent identification
pid_t ps_sid: session identification
pid_t ps_pgpid: process group identification
pid_t ps_fgpid: foreground process group identification
uid_t ps_euid: effective user identification
uid_t ps_ruid: real user identification
uid_t ps_suid: saved user identification
gid_t ps_egid: effective group identification
gid_t ps_rgid: real group identification
gid_t ps_sgid: saved set group identification
long ps_size: total size
time_t ps_starttime: start time
clock_t ps_usertime: user CPU time
clock_t ps_systime: system CPU time
int ps_conttylen: controlling terminal name length
char *ps_conttyptr: controlling terminal name
int ps_pathlen: length of pathname
char *ps_pathptr: pathname
int ps_cmdlen: length of command
char *ps_cmdptr: command and arguments

RETURN VALUE

If successful, w_getpsent returns an integer that identifies the next process that the calling process has access to. A 0 is returned to indicate that there are no more accessible processes. A -1 is returned if the call to w_getpsent is unsuccessful.

PORTABILITY

The w_getpsent function may be useful in OpenEdition applications; however, it is not defined by the POSIX.1 standard and should not be used in portable applications.

EXAMPLE

The following example illustrates the use of w_getpsent to obtain process information:

  #include <sys/types.h>
  #include <sys/ps.h>
  #include <stdio.h>
  #include <stdlib.h>

  #define MAX_CHAR 256

  main()
  {
     int processNum = 0;
     W_PSPROC workArea;

        /* Initialize work area.                   */
     memset(&workArea, 0, sizeof(workArea));

        /* Allocate memory for character strings.  */
     if ((workArea.ps_conttyptr = (char *) malloc(MAX_CHAR)) == NULL) {
        perror("ps_conttyptr memory allocation error");
        abort();
     }
     else
        workArea.ps_conttylen = MAX_CHAR;

     if ((workArea.ps_pathptr = (char *) malloc(MAX_CHAR)) == NULL) {
        perror("ps_pathptr memory allocation error");
        abort();
     }
     else
        workArea.ps_pathlen = MAX_CHAR;

     if ((workArea.ps_cmdptr = (char *) malloc(MAX_CHAR)) == NULL) {
        perror("ps_cmdptr memory allocation error");
        abort();
     }
     else
        workArea.ps_cmdlen = MAX_CHAR;

        /* Get process information.                */
     do {
        processNum = w_getpsent(processNum, &workArea, sizeof(workArea));
        if (processNum == -1)
           perror("error in w_getpsent");
        else  {
           printf("process number = %dn", processNum);
           printf("process ID = %10dn", workArea.ps_pid);
           printf("User ID = %8unn", workArea.ps_ruid);
        }
     } while (processNum != 0 && processNum != 1);
  }