fixed syntax and added some comments to onetimebluh.c

1 files changed, 23 insertions, 4 deletions

diff --git a/onetimebluh.c b/onetimebluh.c
index 2aafbd6..b665fa3 100644
--- a/onetimebluh.c
+++ b/onetimebluh.c
@@ -6,11 +6,12 @@
 #include <errno.h>
 #include <error.h>
 
-void xor(int ed, char* mess, char* keyf, char* outp);
-void keyrand(int nb, char* outp);
-void help(char* av[]);
+void xor(int ed, char* mess, char* keyf, char* outp);		/* operates the bitwise XOR between mess and keyf and puts the output to outp */
+void keyrand(int nb, char* outp);				/* generates random numbers using RAND_bytes from openssl and puts them into outp */
+void help(char* av[]);						/* prints the help message */
 
 int main(int argc, char* argv[]) {
+
 	int opt = 1;
 	int command = 0;
 	int comm = 0;
@@ -19,6 +20,9 @@ int main(int argc, char* argv[]) {
 	char* output = NULL;
 	int nbytes = -1;	// must be resolved temporary workaround (ho sonno)
 
+	/* The following while cycle parses the argv vector to find commands, options and relative arguments
+	   using the function getopt_long */
+
 	while (opt) {
 		int option_index = 0;
 		static struct option options[] = {
@@ -70,11 +74,14 @@ int main(int argc, char* argv[]) {
 		}
 	}
 
+	/* Next section performs some input checks */
+
 	if (command == 0) {
 		printf("No command called \n");
 		exit(EXIT_FAILURE);
 	} else if (command > 1) {
-		printf("Multiple commands called (print usage)\n");
+		printf("Multiple commands called \n");
+		printf("%s [COMMAND] [OPTIONS] ... \n",argv[0]);
 		exit(EXIT_FAILURE);
 	}
 
@@ -83,6 +90,8 @@ int main(int argc, char* argv[]) {
 		exit(EXIT_FAILURE);
 	}
 
+	/* Next section detects the functions to call */
+
 	if (comm == 'e' || comm == 'd') {
 		if (keyfile == NULL) {
 			printf("No key specified: exit! \n");
@@ -101,12 +110,16 @@ void xor(int ed, char* mess, char* keyf, char* outp) {
 	char* defenoutp = "critt";
 	char* defdeoutp = "decritt";
 
+	/* Following if-else block check the existence of the files */
+
 	if (access(mess, F_OK) == -1) {
 		error(errno, errno, mess);
 	} else if (access(keyf, F_OK) == -1) {
 		error(errno, errno, keyf);
 	}
 
+	/* In absence of input by users nex block sets the default values */
+
 	if (outp == NULL) {
 		if (ed == 'e') {
 			printf("WARNING no output name specified using default value 'critt' \n");
@@ -116,6 +129,7 @@ void xor(int ed, char* mess, char* keyf, char* outp) {
 			outp = defdeoutp;
 		}
 	}
+
 	FILE* mex = fopen(mess, "r");
 	FILE* keyx = fopen(keyf, "r");
 	FILE* critt = fopen(outp, "w");
@@ -147,6 +161,8 @@ void keyrand(int nb, char* outp) {
 
 	char* defoutp = "default.key";
 
+	/* Next block controls the inputs and eventually sets the default values */
+
 	if((nb == -1) && (outp == NULL)) {
 		printf("WARNING no option specified usign default values... \n");
 		nb = 256;
@@ -161,12 +177,15 @@ void keyrand(int nb, char* outp) {
 			printf("No byte number specified... using default value: 256 \n");
 			nb = 256;
 		}
+
 		unsigned char key[nb];
 		RAND_bytes(key, nb);
+
 		if (outp == NULL) {
 			outp = defoutp;
 			printf("No output name specified... using default value: default.key \n");
 		}
+
 		FILE* file = fopen(outp, "w");
 		fwrite(key, nb, 1, file);
 		fclose(file);