[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit

Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/app/busybox/src/libbb/pidfile.c b/ap/app/busybox/src/libbb/pidfile.c
new file mode 100644
index 0000000..a48dfc3
--- /dev/null
+++ b/ap/app/busybox/src/libbb/pidfile.c
@@ -0,0 +1,40 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * pid file routines
+ *
+ * Copyright (C) 2007 by Stephane Billiart <stephane.billiart@gmail.com>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+/* Override ENABLE_FEATURE_PIDFILE */
+#define WANT_PIDFILE 1
+#include "libbb.h"
+
+smallint wrote_pidfile;
+
+void FAST_FUNC write_pidfile(const char *path)
+{
+	int pid_fd;
+	char *end;
+	char buf[sizeof(int)*3 + 2];
+	struct stat sb;
+
+	if (!path)
+		return;
+	/* we will overwrite stale pidfile */
+	pid_fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0666);
+	if (pid_fd < 0)
+		return;
+
+	/* path can be "/dev/null"! Test for such cases */
+	wrote_pidfile = (fstat(pid_fd, &sb) == 0) && S_ISREG(sb.st_mode);
+
+	if (wrote_pidfile) {
+		/* few bytes larger, but doesn't use stdio */
+		end = utoa_to_buf(getpid(), buf, sizeof(buf));
+		*end = '\n';
+		full_write(pid_fd, buf, end - buf + 1);
+	}
+	close(pid_fd);
+}