From 9fece2eb88434a7987ffeedadf28b6ef70c52e67 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <goliath@infraroot.at>
Date: Sun, 24 Mar 2019 18:02:17 +0100
Subject: [PATCH] Add hacky utiliy that waits for the presence of some files

Signed-off-by: David Oberhollenzer <goliath@infraroot.at>
---
 .gitignore        |  1 +
 cmd/Makemodule.am |  7 +++-
 cmd/waitfile.c    | 82 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 cmd/waitfile.c

diff --git a/.gitignore b/.gitignore
index 5eb592a..6e74cce 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,5 +21,6 @@ shutdown
 killall5
 runsvc
 gcrond
+waitfile
 
 etc/initd.env
diff --git a/cmd/Makemodule.am b/cmd/Makemodule.am
index e472106..203a840 100644
--- a/cmd/Makemodule.am
+++ b/cmd/Makemodule.am
@@ -14,6 +14,11 @@ killall5_CPPFLAGS = $(AM_CPPFLAGS)
 killall5_CFLAGS = $(AM_CFLAGS)
 killall5_LDFLAGS = $(AM_LDFLAGS)
 
+waitfile_SOURCES = cmd/waitfile.c
+waitfile_CPPFLAGS = $(AM_CPPFLAGS)
+waitfile_CFLAGS = $(AM_CFLAGS)
+waitfile_LDFLAGS = $(AM_LDFLAGS)
+
 SRVHEADERS = cmd/service/servicecmd.h
 
 service_SOURCES = cmd/service/servicecmd.c cmd/service/help.c
@@ -31,4 +36,4 @@ dist_man8_MANS += cmd/shutdown.8 cmd/service/service.8
 EXTRA_DIST += $(SRVHEADERS)
 
 sbin_PROGRAMS += service shutdown
-helper_PROGRAMS += killall5 runsvc
+helper_PROGRAMS += killall5 runsvc waitfile
diff --git a/cmd/waitfile.c b/cmd/waitfile.c
new file mode 100644
index 0000000..e994fd1
--- /dev/null
+++ b/cmd/waitfile.c
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: ISC */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <poll.h>
+
+static int strtoui(const char *str)
+{
+	int i = 0;
+
+	if (!isdigit(*str))
+		return -1;
+
+	while (isdigit(*str)) {
+		if (i > (INT_MAX / 10))
+			return -1;
+
+		i = i * 10 + (*(str++)) - '0';
+	}
+
+	if (*str != '\0')
+		return -1;
+
+	return i;
+}
+
+static void sigproc(int signo)
+{
+	if (signo == SIGALRM) {
+		fputs("waitfile timeout\n", stderr);
+		exit(EXIT_FAILURE);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int i, found, timeout, probetime;
+	struct stat sb;
+
+	if (argc < 4)
+		goto fail_usage;
+
+	timeout = strtoui(argv[1]);
+	probetime = strtoui(argv[2]);
+	if (timeout < 0 || probetime < 0)
+		goto fail_timeout;
+
+	signal(SIGALRM, sigproc);
+	alarm(timeout);
+
+	for (;;) {
+		found = 1;
+
+		for (i = 3; i < argc; ++i) {
+			if (stat(argv[i], &sb) != 0) {
+				found = 0;
+				break;
+			}
+		}
+
+		if (found) {
+			alarm(0);
+			break;
+		}
+
+		poll(NULL, 0, probetime);
+	}
+
+	return EXIT_SUCCESS;
+fail_timeout:
+	fputs("Timeout values must be integers!\n", stderr);
+	goto fail_usage;
+fail_usage:
+	fputs("Usage: waitfile <timeout secs> <probe time ms> FILES...\n",
+	      stderr);
+	return EXIT_FAILURE;
+}