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/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
*/
#include <stdio.h>
#include <sys/wait.h>
#define import_kernel
#define import_knames
#define import_spp
#include <iraf.h>
/* Process table code. The high level code assumes that it can open and close
* processes in any order. The UNIX "wait" primitive, called when a process is
* closed, returns the process status and pid of the first process to exit.
* Hence several calls to wait may be necessary to wait for a given process to
* exit. We hide all this behind the pr_wait call, which waits for a PARTICULAR
* process to exit and returns its exit status.
*
* NOT INTERFACE PROCEDURES. This code is only called internally by other
* kernel procedures. All primitives which execute subprocesses, i.e., ZOPCPR,
* ZOPDPR, ZOSCMD, etc. must call these routines.
*/
struct proctable {
int pr_pid; /* process id */
int pr_active; /* if YES, process is still active */
int pr_inchan; /* input IPC channel */
int pr_outchan; /* output IPC channel */
int pr_exit_status; /* process exit_status */
} prtable[MAXPROCS];
extern int errno;
#ifdef MACOSX
#define POSIX
#endif
/* PR_ENTER -- Make a new entry in the process table. Something is very wrong
* if the table overflows.
*/
void
pr_enter (int pid, int inchan, int outchan)
{
register struct proctable *pr;
struct proctable *pr_findpid();
extern int kernel_panic (char *msg);
if ((pr = pr_findpid (NULL)) == NULL)
kernel_panic ("iraf process table overflow");
else {
pr->pr_pid = pid;
pr->pr_active = YES;
pr->pr_inchan = inchan;
pr->pr_outchan = outchan;
}
}
/* PR_WAIT -- Wait for the process associated with the given pid to terminate
* and return it's exit status. If there is no such process in the table
* return ERR. The table entry is cleared by this call.
*/
int
pr_wait (int pid)
{
register struct proctable *pr;
int error_code;
pid_t waitpid;
struct proctable *pr_findpid();
#ifdef POSIX
int exit_status;
#else
union wait exit_status;
#endif
/* Lookup process in table. Return ERR if there is no entry.
*/
if ((pr = pr_findpid (pid)) == NULL)
return (ERR);
if (pr->pr_active == NO) {
/* Process has already terminated. Clear table entry and return
* exit status (set in a previous call).
*/
pr->pr_pid = (int) 0;
return (pr->pr_exit_status);
} else {
/* Process is in table but has not yet terminated. Call wait until
* the process exits. If other processes exit in the meantime
* save their exit status in the table and mark them inactive.
* If an unknown process terminates ignore it; this will happen
* when a killed bkg process terminates after its process slot
* has been released.
*/
while ((waitpid = wait (&exit_status)) != ERR) {
if ((pr = pr_findpid (waitpid)) != NULL) {
pr->pr_active = NO;
/* The integer argument to exit() is returned in the
* wait struct defined in <sys/wait.h>.
*/
#ifdef POSIX
error_code = WEXITSTATUS(exit_status);
#else
error_code = exit_status.w_T.w_Retcode;
#endif
pr->pr_exit_status = error_code ? error_code : XOK;
if (waitpid == pid) {
pr->pr_pid = (int) 0;
return (pr->pr_exit_status);
}
}
}
return (ERR);
}
}
/* PR_GETIPC -- Get the codes for the IPC channels assigned to a process.
*/
int
pr_getipc (int pid, int *inchan, int *outchan)
{
register struct proctable *pr;
struct proctable *pr_findpid();
/* Lookup process in table. Return ERR if there is no entry.
*/
if ((pr = pr_findpid (pid)) == NULL)
return (ERR);
else {
*inchan = pr->pr_inchan;
*outchan = pr->pr_outchan;
return (pid);
}
}
/* PR_FINDPID -- Search the process table for a process. NULL is returned if
* the process cannot be found, otherwise a pointer to the table entry is
* returned.
*/
struct proctable *
pr_findpid (int pid)
{
register int pr;
for (pr=0; pr < MAXPROCS; pr++) {
if (prtable[pr].pr_pid == pid)
return (&prtable[pr]);
}
return (NULL);
}
/* PR_RELEASE -- Release the table entry for the process. Used when a process
* is killed and we do not wish to wait for process termination.
*/
void
pr_release (int pid)
{
register struct proctable *pr;
if ((pr = pr_findpid (pid)) != NULL)
pr->pr_pid = (int) 0;
}
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