From 2a4afad91a72defee1f97f189bba0920bd63fd9e Mon Sep 17 00:00:00 2001
From: scribblemaniac <scribblemaniac@users.noreply.github.com>
Date: Fri, 15 Oct 2021 22:53:53 -0600
Subject: [PATCH] Add checkpointing support for passphrases

---
 main.c                  | 19 +++++++++++++++++++
 worker.c                |  2 ++
 worker.h                |  2 ++
 worker_batch_pass.inc.h | 23 ++++++++++++++++++++++-
 worker_fast_pass.inc.h  | 23 ++++++++++++++++++++++-
 5 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/main.c b/main.c
index cec31bb..05bfcb7 100644
--- a/main.c
+++ b/main.c
@@ -112,6 +112,7 @@ static void printhelp(FILE *out,const char *progname)
 #ifdef PASSPHRASE
 		"\t-p passphrase  - use passphrase to initialize the random seed with\n"
 		"\t-P  - same as -p, but takes passphrase from PASSPHRASE environment variable\n"
+		"\t-c filename - load/save checkpoint of progress to specified file (requires passphrase)\n"
 #endif
 		,progname,progname);
 	fflush(out);
@@ -393,6 +394,12 @@ int main(int argc,char **argv)
 				setpassphrase(pass);
 				deterministic = 1;
 			}
+			else if (*arg == 'c') {
+				if (argc--)
+					checkpointfile = *argv++;
+				else
+					e_additional();
+			}
 #endif // PASSPHRASE
 			else {
 				fprintf(stderr,"unrecognised argument: -%c\n",*arg);
@@ -465,6 +472,18 @@ int main(int argc,char **argv)
 		goto done;
 	}
 
+	if (checkpointfile) {
+		// Read current checkpoint position if file exists
+		FILE *checkout = fopen(checkpointfile, "r");
+		if (checkout) {
+			if(fread(checkpoint, 1, SEED_LEN, checkout) != SEED_LEN) {
+				fprintf(stderr,"failed to read checkpoint file\n");
+				exit(1);
+			}
+			fclose(checkout);
+		}
+	}
+
 	filters_prepare();
 
 	filters_print();
diff --git a/worker.c b/worker.c
index f0aaf62..475d2a3 100644
--- a/worker.c
+++ b/worker.c
@@ -63,6 +63,8 @@ void worker_init(void)
 
 pthread_mutex_t determseed_mutex;
 u8 determseed[SEED_LEN];
+u8 checkpoint[SEED_LEN];
+const char *checkpointfile = 0;
 #endif
 
 
diff --git a/worker.h b/worker.h
index 7f50f6f..d20d037 100644
--- a/worker.h
+++ b/worker.h
@@ -33,6 +33,8 @@ VEC_STRUCT(statsvec,struct statstruct);
 #ifdef PASSPHRASE
 extern pthread_mutex_t determseed_mutex;
 extern u8 determseed[SEED_LEN];
+extern u8 checkpoint[SEED_LEN];
+extern const char *checkpointfile;
 #endif
 
 extern void worker_init(void);
diff --git a/worker_batch_pass.inc.h b/worker_batch_pass.inc.h
index 3676eec..ecdcb45 100644
--- a/worker_batch_pass.inc.h
+++ b/worker_batch_pass.inc.h
@@ -36,18 +36,39 @@ void *worker_batch_pass(void *task)
 
 	sname = makesname();
 
+	// load checkpoint
+	pthread_mutex_lock(&determseed_mutex);
+	for (int i = 0; i < SEED_LEN; i++)
+		determseed[i] += checkpoint[i];
+	pthread_mutex_unlock(&determseed_mutex);
+
 initseed:
 #ifdef STATISTICS
 	++st->numrestart.v;
 #endif
 
 	pthread_mutex_lock(&determseed_mutex);
-	for (int i = 0; i < SEED_LEN; i++)
+	for (int i = 0; i < SEED_LEN; i++) {
+		++checkpoint[i];
 		if (++determseed[i])
 			break;
+	}
 	memcpy(seed, determseed, SEED_LEN);
 	pthread_mutex_unlock(&determseed_mutex);
 
+	if (checkpointfile) {
+		FILE *checkout = fopen(checkpointfile, "w");
+		if (!checkout) {
+			fprintf(stderr,"cannot open checkpoint file for writing\n");
+			exit(1);
+		}
+		if(fwrite(checkpoint, 1, SEED_LEN, checkout) != SEED_LEN) {
+			fprintf(stderr,"cannot write to checkpoint file\n");
+			exit(1);
+		}
+		fclose(checkout);
+	}
+
 	ed25519_seckey_expand(sk,seed);
 
 	ge_scalarmult_base(&ge_public,sk);
diff --git a/worker_fast_pass.inc.h b/worker_fast_pass.inc.h
index 2d482b3..3f281b5 100644
--- a/worker_fast_pass.inc.h
+++ b/worker_fast_pass.inc.h
@@ -33,18 +33,39 @@ void *worker_fast_pass(void *task)
 
 	sname = makesname();
 
+	// load checkpoint
+	pthread_mutex_lock(&determseed_mutex);
+	for (int i = 0; i < SEED_LEN; i++)
+		determseed[i] += checkpoint[i];
+	pthread_mutex_unlock(&determseed_mutex);
+
 initseed:
 #ifdef STATISTICS
 	++st->numrestart.v;
 #endif
 
 	pthread_mutex_lock(&determseed_mutex);
-	for (int i = 0; i < SEED_LEN; i++)
+	for (int i = 0; i < SEED_LEN; i++) {
+		++checkpoint[i];
 		if (++determseed[i])
 			break;
+	}
 	memcpy(seed, determseed, SEED_LEN);
 	pthread_mutex_unlock(&determseed_mutex);
 
+	if (checkpointfile) {
+		FILE *checkout = fopen(checkpointfile, "w");
+		if (!checkout) {
+			fprintf(stderr,"cannot open checkpoint file for writing\n");
+			exit(1);
+		}
+		if(fwrite(checkpoint, 1, SEED_LEN, checkout) != SEED_LEN) {
+			fprintf(stderr,"cannot write to checkpoint file\n");
+			exit(1);
+		}
+		fclose(checkout);
+	}
+
 	ed25519_seckey_expand(sk,seed);
 
 	ge_scalarmult_base(&ge_public,sk);