1 files changed, 66 insertions, 0 deletions
diff --git a/src/cmd/dwm/util.c b/src/cmd/dwm/util.c
new file mode 100644
index 0000000..0db71cc
--- /dev/null
+++ b/src/cmd/dwm/util.c
@@ -0,0 +1,66 @@
+/* See LICENSE file for copyright and license details. */
+#include "dwm.h"
+
+void
+fatal(char *fmt, ...) {
+    va_list args;
+
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+
+    if(fmt[0] && fmt[strlen(fmt)-1] == ':') {
+        fputc(' ', stderr);
+        perror(NULL);
+    } else {
+        fputc('\n', stderr);
+    }
+
+    exit(1);
+}
+
+void *
+ecalloc(size_t nmemb, size_t size)
+{
+	void *p;
+
+	if (!(p = calloc(nmemb, size)))
+		fatal("calloc:");
+	return p;
+}
+
+pid_t
+getparentprocess(pid_t p)
+{
+	uint v = 0;
+
+#if defined(__linux__)
+	io·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;
+}