gods

commit 98c4949aa2185b3268f95f79f0ff5f9979071659
parent b994f7efa9c60d5152661c090d2a7cb75a4c970d
Author: Naveen Narayanan <zerous@nocebo.space>
Date:   Sat, 23 Oct 2021 13:18:55 +0200

Daemonize sdog

Diffstat:
A
arg.h
 | 
50
++++++++++++++++++++++++++++++++++++++++++++++++++
M
main.c
 | 
42
+++++++++++++++++++++++++++++++++++++++++-

2 files changed, 91 insertions(+), 1 deletion(-)
diff --git a/arg.h b/arg.h
@@ -0,0 +1,50 @@
+/*
+ * Copy me if you can.
+ * by 20h
+ */
+
+#ifndef ARG_H__
+#define ARG_H__
+
+extern char *argv0;
+
+/* use main(int argc, char *argv[]) */
+#define ARGBEGIN	for (argv0 = *argv, argv++, argc--;\
+					argv[0] && argv[0][0] == '-'\
+					&& argv[0][1];\
+					argc--, argv++) {\
+				char argc_;\
+				char **argv_;\
+				int brk_;\
+				if (argv[0][1] == '-' && argv[0][2] == '\0') {\
+					argv++;\
+					argc--;\
+					break;\
+				}\
+				int i_;\
+				for (i_ = 1, brk_ = 0, argv_ = argv;\
+						argv[0][i_] && !brk_;\
+						i_++) {\
+					if (argv_ != argv)\
+						break;\
+					argc_ = argv[0][i_];\
+					switch (argc_)
+
+#define ARGEND			}\
+			}
+
+#define ARGC()		argc_
+
+#define EARGF(x)	((argv[0][i_+1] == '\0' && argv[1] == NULL)?\
+				((x), abort(), (char *)0) :\
+				(brk_ = 1, (argv[0][i_+1] != '\0')?\
+					(&argv[0][i_+1]) :\
+					(argc--, argv++, argv[0])))
+
+#define ARGF()		((argv[0][i_+1] == '\0' && argv[1] == NULL)?\
+				(char *)0 :\
+				(brk_ = 1, (argv[0][i_+1] != '\0')?\
+					(&argv[0][i_+1]) :\
+					(argc--, argv++, argv[0])))
+
+#endif
diff --git a/main.c b/main.c
@@ -1,4 +1,5 @@
 #include <sys/stat.h>
+#include <sys/types.h>
 
 #include <err.h>
 #include <errno.h>
@@ -9,6 +10,8 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "arg.h"
+
 #include "attack.h"
 #include "config.h"
 #include "fw.h"
@@ -21,6 +24,7 @@
 int fd_black;
 int fd_white;
 int ignore;
+char *argv0;
 
 static char buf[BUFSZ];
 SLIST_HEAD(lhead, attacker) head = SLIST_HEAD_INITIALIZER(head);
@@ -135,16 +139,52 @@ cleanup()
 	free(prev);
 }
 
+void
+usage(void)
+{
+	fprintf(stderr, "usage: sdog [-d]\n");
+	exit(1);
+}
+
+void
+daemon_init(void)
+{
+	pid_t p;
+
+	if ((p = fork()) == -1)
+		err(1, "fork failed");
+	else if (p != 0)
+		exit(0);
+	if (setsid() == -1)
+		err(1, "setsid failed");
+	if (chdir("/etc/gods") == -1)
+		err(1, "chdir failed: %s", "/etc/gods");
+	umask(0);
+}
+
 int
 main(int argc, char **argv)
 {
 	FILE *fp;
 	char *line;
 	char bf[16];
-	int fd, found, ret;
+	int debug, fd, found, ret;
 	struct attacker *a;
 	time_t now;
 
+	debug = 0;
+
+	ARGBEGIN {
+		case 'd':
+			debug = 1;
+			break;
+		default:
+			usage();
+	} ARGEND
+
+	if (!debug)
+		daemon_init();
+
 	fd = open(sshlog, O_RDONLY);
 	if (fd == -1)
 		err(1, "open failed: %s", sshlog);