dedup

commit 5cc2cb4d8ed4f3866cc99a3c2e50e4f244f6f836
parent 3cb8c88abd3f830a2637a8b666402d063df0e7e4
Author: sin <sin@2f30.org>
Date:   Sun, 17 Feb 2019 11:23:29 +0000

Add support for attaching descriptive messages to snapshots

Diffstat:
M
dedup.1
 | 
9
++++++---
M
dedup.c
 | 
29
++++++++++++++++++++++++-----

2 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/dedup.1 b/dedup.1
@@ -1,4 +1,4 @@
-.Dd March 21, 2018
+.Dd Feb 17, 2019
 .Dt DEDUP 1
 .Os
 .Sh NAME
@@ -9,6 +9,7 @@
 .Op Fl clv
 .Op Fl e Ar id
 .Op Fl r Ar root
+.Op Fl m Ar message
 .Op file
 .Sh DESCRIPTION
 .Nm
@@ -20,14 +21,16 @@ only handles a single file at a time, so using tar is advised.
 .It Fl c
 Perform a consistency check on the deduplication storage.
 .It Fl l
-List revisions by hash.
+List snapshots by hash.
 .It Fl v
 Enable verbose mode.
 .It Fl e Ar id
-Extract revision with the specified id.
+Extract snapshot with the specified id.
 .It Fl r Ar root
 Set the root directory where the .cache, .index and .store
 files will be created.
+.It Fl m Ar message
+Attach a descriptive message to the snapshot.
 .El
 .Sh AUTHORS
 .An Dimitris Papastamos Aq Mt sin@2f30.org ,
diff --git a/dedup.c b/dedup.c
@@ -19,6 +19,7 @@
 #define BLKSIZ (1024 * 512)
 #define WINSIZ 1024
 #define HASHMSK ((1ul << 21) - 1)
+#define MSGSIZ 256
 #define MDSIZ SHA256_DIGEST_LENGTH
 
 #define ROTL(x, y) (((x) << (y)) | ((x) >> (32 - (y))))
@@ -44,6 +45,7 @@ struct bdescr {
 /* index file entry */
 struct ent {
 	uint64_t size;
+	uint8_t msg[MSGSIZ];
 	uint8_t md[MDSIZ];	/* hash of file */
 	uint64_t nblks;
 	struct bdescr bdescr[];
@@ -363,7 +365,7 @@ lookup_blk(uint8_t *md)
 }
 
 void
-dedup(int fd)
+dedup(int fd, char *msg)
 {
 	uint8_t *buf;
 	struct ent *ent;
@@ -421,8 +423,19 @@ dedup(int fd)
 	}
 
 	if (ent->nblks > 0) {
+		size_t size;
+
 		/* Calculate hash and add this entry to the index */
 		SHA256_Final(ent->md, &ctx);
+
+		if (msg != NULL && msg[0] != '\0') {
+			size = strlen(msg) + 1;
+			if (size > sizeof(ent->msg))
+				size = sizeof(ent->msg);
+			memcpy(ent->msg, msg, size);
+			ent->msg[size - 1] = '\0';
+		}
+
 		append_ent(ent);
 	}
 
@@ -493,7 +506,10 @@ int
 list(struct ent *ent, void *arg)
 {
 	print_md(ent->md, sizeof(ent->md));
-	putchar('\n');
+	if (ent->msg)
+		printf("\t%s\n", ent->msg);
+	else
+		putchar('\n');
 	return WALK_CONTINUE;
 }
 
@@ -630,7 +646,7 @@ term(void)
 void
 usage(void)
 {
-	fprintf(stderr, "usage: %s [-clv] [-e id] [-r root] [file]\n", argv0);
+	fprintf(stderr, "usage: %s [-clv] [-e id] [-r root] [-m message] [file]\n", argv0);
 	exit(1);
 }
 
@@ -638,7 +654,7 @@ int
 main(int argc, char *argv[])
 {
 	uint8_t md[MDSIZ];
-	char *id = NULL, *root = NULL;
+	char *id = NULL, *root = NULL, *msg = NULL;
 	int fd = -1, lflag = 0, cflag = 0;
 
 	ARGBEGIN {
@@ -654,6 +670,9 @@ main(int argc, char *argv[])
 	case 'r':
 		root = EARGF(usage());
 		break;
+	case 'm':
+		msg = EARGF(usage());
+		break;
 	case 'v':
 		verbose = 1;
 		break;
@@ -704,7 +723,7 @@ main(int argc, char *argv[])
 		str2bin(id, md);
 		walk(extract, &(struct extract_args){ .md = md, .fd = fd });
 	} else {
-		dedup(fd);
+		dedup(fd, msg);
 	}
 
 	term();