Add --retry-forever option.

This option, if set, causes tarsnap to continue trying to reconnect to
the tarsnap server forever, instead of giving up after 5-10 minutes.
This option may be useful for people with excessively flaky networks
or on mobile devices which regularly lose their internet connections
for extended periods of time; it will however not be turned on by
default since the combination of a network (mis)configuration which
breaks tarsnap and a system administrator who does not verify that
backups have completed could result in a tarsnap process "lingering"
for an extended period of time without overtly failing.

This option has not been added to the tarsnap man page yet.  That
should happen before the next release.

lib/netpacket/netpacket_op.c

@@ -32,6 +32,9 @@ static int reconnect_wait[MAXRECONNECTS + 1] = {
     0, 0, 1, 2, 4, 8, 15, 30, 60, 90, 90
 };
 
+/* Global tarsnap option declared in tarsnap_opt.h. */
+int tarsnap_opt_retry_forever = 0;
+
 /* Time before which we shouldn't print a "connection lost" warning. */
 static struct timeval next_connlost_warning = { 0, 0};
 
@@ -241,6 +244,8 @@ reconnect(NETPACKET_CONNECTION * NPC)
 
 	/* Have we lost our connection / failed to connect too many times? */
 	NPC->ndrops += 1;
+	if (tarsnap_opt_retry_forever && NPC->ndrops > MAXRECONNECTS)
+		NPC->ndrops = MAXRECONNECTS;
 	if ((NPC->ndrops > MAXRECONNECTS) ||
 	    (NPC->serveralive == 0 && NPC->ndrops > MAXRECONNECTS_AWOL)) {
 		warn0("Too many network failures");

tar/bsdtar.c

@@ -469,6 +469,9 @@ main(int argc, char **argv)
 		case OPTION_NO_QUIET:
 			optq_push(bsdtar, "no-quiet", NULL);
 			break;
+		case OPTION_NO_RETRY_FOREVER:
+			optq_push(bsdtar, "no-retry-forever", NULL);
+			break;
 		case OPTION_NO_SAME_OWNER: /* GNU tar */
 			bsdtar->extract_flags &= ~ARCHIVE_EXTRACT_OWNER;
 			break;
@@ -531,6 +534,9 @@ main(int argc, char **argv)
 		case OPTION_RECOVER:
 			set_mode(bsdtar, opt, "--recover");
 			break;
+		case OPTION_RETRY_FOREVER:
+			optq_push(bsdtar, "retry-forever", NULL);
+			break;
 		case OPTION_SNAPTIME: /* multitar */
 			optq_push(bsdtar, "snaptime", bsdtar->optarg);
 			break;
@@ -1448,6 +1454,11 @@ dooption(struct bsdtar *bsdtar, const char * conf_opt,
 			goto optset;
 
 		bsdtar->option_quiet_set = 1;
+	} else if (strcmp(conf_opt, "no-retry-forever") == 0) {
+		if (bsdtar->option_retry_forever_set)
+			goto optset;
+
+		bsdtar->option_retry_forever_set = 1;
 	} else if (strcmp(conf_opt, "no-snaptime") == 0) {
 		if (bsdtar->option_snaptime_set)
 			goto optset;
@@ -1477,6 +1488,12 @@ dooption(struct bsdtar *bsdtar, const char * conf_opt,
 
 		bsdtar->option_quiet = 1;
 		bsdtar->option_quiet_set = 1;
+	} else if (strcmp(conf_opt, "retry-forever") == 0) {
+		if (bsdtar->option_retry_forever_set)
+			goto optset;
+
+		tarsnap_opt_retry_forever = 1;
+		bsdtar->option_retry_forever_set = 1;
 	} else if (strcmp(conf_opt, "snaptime") == 0) {
 		if (bsdtar->mode != 'c')
 			goto badmode;

tar/bsdtar.h

@@ -105,6 +105,7 @@ struct bsdtar {
 	int		  option_no_config_include_set;
 	int		  option_quiet;
 	int		  option_quiet_set;
+	int		  option_retry_forever_set;
 	int		  option_insane_filesystems;
 	int		  option_insane_filesystems_set;
 	const char	**configfiles;		/* --configfile */
@@ -199,6 +200,7 @@ enum {
 	OPTION_NO_NODUMP,
 	OPTION_NO_PRINT_STATS,
 	OPTION_NO_QUIET,
+	OPTION_NO_RETRY_FOREVER,
 	OPTION_NO_SAME_OWNER,
 	OPTION_NO_SAME_PERMISSIONS,
 	OPTION_NO_SNAPTIME,
@@ -214,6 +216,7 @@ enum {
 	OPTION_RECOVER,
 	OPTION_RECOVER_DELETE,	/* Operation mode, not a real option */
 	OPTION_RECOVER_WRITE,	/* Operation mode, not a real option */
+	OPTION_RETRY_FOREVER,
 	OPTION_QUIET,
 	OPTION_SNAPTIME,
 	OPTION_STORE_ATIME,

tar/cmdline.c

@@ -130,6 +130,7 @@ static struct option {
 	{ "no-print-stats",	  0, OPTION_NO_PRINT_STATS },
 	{ "no-quiet",		  0, OPTION_NO_QUIET },
 	{ "no-recursion",         0, 'n' },
+	{ "no-retry-forever",	  0, OPTION_NO_RETRY_FOREVER },
 	{ "no-same-owner",	  0, OPTION_NO_SAME_OWNER },
 	{ "no-same-permissions",  0, OPTION_NO_SAME_PERMISSIONS },
 	{ "no-snaptime",	  0, OPTION_NO_SNAPTIME },
@@ -144,6 +145,7 @@ static struct option {
 	{ "quiet",		  0, OPTION_QUIET },
 	{ "read-full-blocks",	  0, 'B' },
 	{ "recover",		  0, OPTION_RECOVER },
+	{ "retry-forever",	  0, OPTION_RETRY_FOREVER },
 	{ "same-owner",	          0, OPTION_SAME_OWNER },
 	{ "same-permissions",     0, 'p' },
 	{ "snaptime",		  1, OPTION_SNAPTIME },

tar/tarsnap_opt.h

@@ -4,6 +4,9 @@
 /* Use multiple TCP connections when writing an archive. */
 extern int tarsnap_opt_aggressive_networking;
 
+/* Keep trying forever if connection lost. */
+extern int tarsnap_opt_retry_forever;
+
 /* Print statistics using "human-readable" SI prefixes. */
 extern int tarsnap_opt_humanize_numbers;