From 41a74402f045daf78ea3ab24d862e1f05f7f0cec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Fri, 9 Apr 2021 23:00:56 +0300
Subject: [PATCH] Add support for specifying the input and output file

---
 puer.c | 49 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 12 deletions(-)

diff --git a/puer.c b/puer.c
index ba3afca..e10c69a 100644
--- a/puer.c
+++ b/puer.c
@@ -543,8 +543,8 @@ ssize_t passphrase_prompt(unsigned char *passphrase, size_t size, const char *pr
 	return index - 1;
 }
 
-ssize_t passphrase_file(char *passfile, unsigned char passphrase[], size_t size) {
-	int file = open(passfile, O_RDONLY);
+ssize_t passphrase_file(char *passfilepath, unsigned char passphrase[], size_t size) {
+	int file = open(passfilepath, O_RDONLY);
 
 	// Read until newline
 	size_t index = 0;
@@ -579,21 +579,25 @@ ssize_t passphrase_file(char *passfile, unsigned char passphrase[], size_t size)
 }
 
 void usage(char *name) {
-	fprintf(stderr, "Usage: %s -d | -e [-f] [-p passfile]\n\n", name);
-	fprintf(stderr, "-d Decrypt\n");
-	fprintf(stderr, "-e Encrypt\n");
-	fprintf(stderr, "-f Force output to terminal\n");
-	fprintf(stderr, "-p Read passphrase from a file instead of the terminal.\n");
+	fprintf(stderr, "Usage: %s -d | -e [-f] [-p passfile] [-i infile] [-o outfile]\n\n", name);
+	fprintf(stderr, "-d            Decrypt\n");
+	fprintf(stderr, "-e            Encrypt\n");
+	fprintf(stderr, "-f            Force output to terminal\n");
+	fprintf(stderr, "-p passfile   Read passphrase from a file instead of the terminal.\n");
+	fprintf(stderr, "-i infile     Read from a file instead of the terminal.\n");
+	fprintf(stderr, "-o outfile    Write to a file instead of the terminal.\n");
 }
 
 int main(int argc, char *argv[]) {
 	bool encrypting = false;
 	bool decrypting = false;
 	bool force = false;
-	char *passfile = NULL;
+	char *passfilepath = NULL;
+	char *infilepath = NULL;
+	char *outfilepath = NULL;
 
 	int opt;
-	while ((opt = getopt(argc, argv, "defp:")) != -1) {
+	while ((opt = getopt(argc, argv, "defp:i:o:")) != -1) {
 		switch (opt) {
 			case 'd':
 				decrypting = true;
@@ -605,7 +609,13 @@ int main(int argc, char *argv[]) {
 				force = true;
 				break;
 			case 'p':
-				passfile = optarg;
+				passfilepath = optarg;
+				break;
+			case 'i':
+				infilepath = optarg;
+				break;
+			case 'o':
+				outfilepath = optarg;
 				break;
 			default:
 				usage(argv[0]);
@@ -626,6 +636,21 @@ int main(int argc, char *argv[]) {
 	FILE *infile = stdin;
 	FILE *outfile = stdout;
 
+	if (infilepath != NULL) {
+		infile = fopen(infilepath, "r");
+		if (infile == NULL) {
+			perror("Failed to open input file");
+			exit(1);
+		}
+	}
+	if (outfilepath != NULL) {
+		outfile = fopen(outfilepath, "w");
+		if (outfile == NULL) {
+			perror("Failed to open output file");
+			exit(1);
+		}
+	}
+
 	if (encrypting && !force && isatty(fileno(outfile))) {
 		fprintf(stderr, "Refusing to print encrypted (binary) data to terminal. Use -f to force output.\n");
 		exit(1);
@@ -655,7 +680,7 @@ int main(int argc, char *argv[]) {
 	// Read passphrase
 	unsigned char passphrase[128];
 	ssize_t passphrase_len;
-	if (passfile == NULL) {
+	if (passfilepath == NULL) {
 		// Read from terminal if no passfile specified
 		passphrase_len = passphrase_prompt(passphrase, sizeof(passphrase), "passphrase: ");
 		if (passphrase_len == -1) {
@@ -683,7 +708,7 @@ int main(int argc, char *argv[]) {
 			explicit_bzero(confirm, sizeof(confirm));
 		}
 	} else {
-		passphrase_len = passphrase_file(passfile, passphrase, sizeof(passphrase));
+		passphrase_len = passphrase_file(passfilepath, passphrase, sizeof(passphrase));
 		if (passphrase_len == -1) {
 			explicit_bzero(passphrase, sizeof(passphrase));
 			exit(1);