rc

commit cdebef2d61705d76b56ece92f2e7e18a0f78fcb4
parent 28764f40827bc3c4ef9bfe1154c66d8537568752
Author: tgoodwin <tgoodwin>
Date:   Mon, 29 Sep 1997 14:48:47 +0000

Initial revision

Diffstat:
A
wait.c
 | 
129
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 129 insertions(+), 0 deletions(-)
diff --git a/wait.c b/wait.c
@@ -0,0 +1,129 @@
+#include "rc.h"
+
+#include <errno.h>
+#include <setjmp.h>
+#include <sys/wait.h>
+
+#include "jbwrap.h"
+
+bool forked = FALSE;
+
+static pid_t rc_wait(int *);
+
+typedef struct Pid Pid;
+
+static struct Pid {
+	pid_t pid;
+	int stat;
+	bool alive;
+	Pid *n;
+} *plist = NULL;
+
+extern pid_t rc_fork() {
+	Pid *new;
+	pid_t pid = fork();
+	switch (pid) {
+	case -1:
+		uerror("fork");
+		rc_error(NULL);
+		/* NOTREACHED */
+	case 0:
+		forked = TRUE;
+		sigchk();
+		return 0;
+	default:
+		new = enew(Pid);
+		new->pid = pid;
+		new->alive = TRUE;
+		new->n = plist;
+		plist = new;
+		return pid;
+	}
+}
+
+extern pid_t rc_wait4(pid_t pid, int *stat, bool nointr) {
+	Pid *r, *prev;
+	int ret;
+	/* first look for a child which may already have exited */
+again:	for (r = plist, prev = NULL; r != NULL; prev = r, r = r->n)
+		if (r->pid == pid)
+			break;
+	if (r == NULL) {
+		errno = ECHILD; /* no children */
+		uerror("wait");
+		*stat = 0x100; /* exit(1) */
+		return -1;
+	}
+	if (r->alive) {
+		while (pid != (ret = rc_wait(stat))) {
+			Pid *q;
+			if (ret < 0) {
+				if (nointr)
+					goto again;
+				return ret;
+			}
+			for (q = plist; q != NULL; q = q->n)
+				if (q->pid == ret) {
+					q->alive = FALSE;
+					q->stat = *stat;
+					break;
+				}
+		}
+	} else
+		*stat = r->stat;
+	if (prev == NULL)
+		plist = r->n; /* remove element from head of list */
+	else
+		prev->n = r->n;
+	efree(r);
+	return pid;
+}
+
+extern List *sgetapids() {
+	List *r;
+	Pid *p;
+	for (r = NULL, p = plist; p != NULL; p = p->n) {
+		List *q;
+		if (!p->alive)
+			continue;
+		q = nnew(List);
+		q->w = nprint("%d", p->pid);
+		q->m = NULL;
+		q->n = r;
+		r = q;
+	}
+	return r;
+}
+
+extern void waitforall() {
+	int stat;
+	while (plist != NULL) {
+		int pid = rc_wait4(plist->pid, &stat, FALSE);
+		if (pid > 0)
+			setstatus(pid, stat);
+		else
+			set(FALSE);
+		sigchk();
+	}
+}
+
+/*
+   rc_wait: a wait() wrapper that interfaces wait() w/rc signals.
+   Note that the signal queue is not checked in this fn; someone
+   may want to resume the wait() without delivering any signals.
+*/
+
+static pid_t rc_wait(int *stat) {
+	int r;
+	interrupt_happened = FALSE;
+	if (!setjmp(slowbuf.j)) {
+		slow = TRUE;
+		if (!interrupt_happened)
+			r = wait(stat);
+		else
+			r = -1;
+	} else
+		r = -1;
+	slow = FALSE;
+	return r;
+}