Initial commit

.gitignore

@@ -0,0 +1 @@
+./bin

Makefile

@@ -0,0 +1,9 @@
+OUTPUT_DIR = ./bin
+OUTPUT = -o $(OUTPUT_DIR)/PROG
+SOURCES = *.c
+
+build: output_dir
+	gcc -Wall ${SOURCES} ${OUTPUT:PROG=upgrade}
+
+output_dir:
+	mkdir -p ${OUTPUT_DIR}

main.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <unistd.h>
+
+int main(int argc, char **argv) {
+	struct flock fl;
+	int c;
+	int sleep_time;
+	int fd;
+
+	static const struct option long_options[] = {
+		{"file", required_argument, NULL, 'f'},
+		{"sleep", required_argument, NULL, 's'},
+		{0, 0, 0, 0}
+	};
+
+	while(1) {
+		int option_index = 0;
+		c = getopt_long(argc, argv, "f:s:", long_options, &option_index);
+
+		if (c == -1) {
+			break;
+		}
+
+		// No input sanitation
+		switch(c) {
+			case 'f':
+				fd=open(optarg, O_RDONLY);
+				break;
+			case 's':
+				sleep_time = atoi(optarg);
+				break;
+		}
+	}
+
+	fl.l_type=F_RDLCK;
+	fl.l_whence=SEEK_SET;
+	fl.l_start=0;
+	fl.l_len=0;
+	if(fcntl(fd,F_SETLK,&fl) == -1) {
+		printf("ERROR\n");
+		return 1;
+	}
+	do {
+		sleep(sleep_time);
+		break;
+	} while(1);
+
+	return 0;
+}