From e5888a1ffdae813d7575f5fb02275c6bb07e5199 Mon Sep 17 00:00:00 2001
From: Taru Karttunen <taruti@taruti.net>
Date: Wed, 30 Mar 2011 15:46:40 +0300
Subject: Import sources from 2011-03-30 iso image

---
 sys/src/ape/lib/bsd/popen.c | 84 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100755 sys/src/ape/lib/bsd/popen.c

(limited to 'sys/src/ape/lib/bsd/popen.c')

diff --git a/sys/src/ape/lib/bsd/popen.c b/sys/src/ape/lib/bsd/popen.c
new file mode 100755
index 000000000..32af1de3d
--- /dev/null
+++ b/sys/src/ape/lib/bsd/popen.c
@@ -0,0 +1,84 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+#define MAXFORKS	20
+#define NSYSFILE	3
+#define	tst(a,b)	(*mode == 'r'? (b) : (a))
+#define	RDR	0
+#define	WTR	1
+
+struct a_fork {
+	short	done;
+	short	fd;
+	int	pid;
+	int	status;
+};
+static struct a_fork the_fork[MAXFORKS];
+
+FILE *
+popen(char *cmd, char *mode)
+{
+	int p[2];
+	int myside, hisside, pid;
+	int i, ind;
+
+	for (ind = 0; ind < MAXFORKS; ind++)
+		if (the_fork[ind].pid == 0)
+			break;
+	if (ind == MAXFORKS)
+		return NULL;
+	if(pipe(p) < 0)
+		return NULL;
+	myside = tst(p[WTR], p[RDR]);
+	hisside = tst(p[RDR], p[WTR]);
+	switch (pid = fork()) {
+	case -1:
+		return NULL;
+	case 0:
+		/* myside and hisside reverse roles in child */
+		close(myside);
+		dup2(hisside, tst(0, 1));
+		for (i=NSYSFILE; i<FOPEN_MAX; i++)
+			close(i);
+		execl("/bin/ape/sh", "sh", "-c", cmd, NULL);
+		_exit(1);
+	default:
+		the_fork[ind].pid = pid;
+		the_fork[ind].fd = myside;
+		the_fork[ind].done = 0;
+		close(hisside);
+		return(fdopen(myside, mode));
+	}
+}
+
+int
+pclose(FILE *ptr)
+{
+	int f, r, ind;
+	int status;
+
+	f = fileno(ptr);
+	fclose(ptr);
+	for (ind = 0; ind < MAXFORKS; ind++)
+		if (the_fork[ind].fd == f && the_fork[ind].pid != 0)
+			break;
+	if (ind == MAXFORKS)
+		return 0;
+	if (!the_fork[ind].done) {
+		do {
+			r = wait(&status);
+			for (f = 0; f < MAXFORKS; f++)
+				if (the_fork[f].pid == r) {
+					the_fork[f].done = 1;
+					the_fork[f].status = status;
+					break;
+				}
+		} while(r != the_fork[ind].pid && r != -1);
+		the_fork[ind].status = r == -1 ? -1 : status;
+	}
+	the_fork[ind].pid = 0;
+	return (the_fork[ind].status);
+}
-- 
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