hand added swallow patch

1 files changed, 37 insertions, 4 deletions

diff --git a/sys/cmd/dwm/util.c b/sys/cmd/dwm/util.c
index 1306c9c..445d479 100644
--- a/sys/cmd/dwm/util.c
+++ b/sys/cmd/dwm/util.c
@@ -1,8 +1,5 @@
 /* See LICENSE file for copyright and license details. */
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+#include "dwm.h"
 
 void
 fatal(char *fmt, ...) {
@@ -31,3 +28,39 @@ ecalloc(size_t nmemb, size_t size)
 		fatal("calloc:");
 	return p;
 }
+
+pid_t
+getparentprocess(pid_t p)
+{
+	uint v = 0;
+
+#if defined(__linux__)
+	Stream *f;
+	char buf[256];
+	snprintf(buf, sizeof(buf) - 1, "/proc/%u/stat", (unsigned)p);
+
+	if (!(f = fopen(buf, "r")))
+		return (pid_t)0;
+
+	if (fscanf(f, "%*u %*s %*c %u", (unsigned *)&v) != 1)
+		v = (pid_t)0;
+	fclose(f);
+#elif defined(__FreeBSD__)
+	struct kinfo_proc *proc = kinfo_getproc(p);
+	if (!proc)
+		return (pid_t)0;
+
+	v = proc->ki_ppid;
+	free(proc);
+#endif
+	return (pid_t)v;
+}
+
+int
+isdescendent(pid_t p, pid_t c)
+{
+	while (p != c && c != 0)
+		c = getparentprocess(c);
+
+	return (int)c;
+}