discover: Add safe mode

Safe mode configures the discover server to not start any device
parsing; this can be used to diagnose any problems with early device
handing.

In safe mode, we don't initialise any of the device sources - udev,
network and user events are disabled.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

3 files changed, 11 insertions, 1 deletions

diff --git a/lib/pb-config/pb-config.c b/lib/pb-config/pb-config.c
index 2adc7b2..d43a5ab 100644
--- a/lib/pb-config/pb-config.c
+++ b/lib/pb-config/pb-config.c
@@ -42,6 +42,7 @@ struct config *config_copy(void *ctx, const struct config *src)
 	dest = talloc(ctx, struct config);
 	dest->autoboot_enabled = src->autoboot_enabled;
 	dest->autoboot_timeout_sec = src->autoboot_timeout_sec;
+	dest->safe_mode = src->safe_mode;
 
 	dest->network.n_interfaces = src->network.n_interfaces;
 	dest->network.interfaces = talloc_array(dest, struct interface_config *,
diff --git a/lib/pb-protocol/pb-protocol.c b/lib/pb-protocol/pb-protocol.c
index 67e1f9e..d39c1c4 100644
--- a/lib/pb-protocol/pb-protocol.c
+++ b/lib/pb-protocol/pb-protocol.c
@@ -267,7 +267,8 @@ int pb_protocol_config_len(const struct config *config)
 	unsigned int i, len;
 
 	len =	4 /* config->autoboot_enabled */ +
-		4 /* config->autoboot_timeout_sec */;
+		4 /* config->autoboot_timeout_sec */ +
+		4 /* config->safe_mode */;
 
 	len += 4;
 	for (i = 0; i < config->network.n_interfaces; i++)
@@ -448,6 +449,9 @@ int pb_protocol_serialise_config(const struct config *config,
 	*(uint32_t *)pos = __cpu_to_be32(config->autoboot_timeout_sec);
 	pos += 4;
 
+	*(uint32_t *)pos = config->safe_mode;
+	pos += 4;
+
 	*(uint32_t *)pos = __cpu_to_be32(config->network.n_interfaces);
 	pos += 4;
 	for (i = 0; i < config->network.n_interfaces; i++) {
@@ -862,6 +866,10 @@ int pb_protocol_deserialise_config(struct config *config,
 	if (read_u32(&pos, &len, &config->autoboot_timeout_sec))
 		goto out;
 
+	if (read_u32(&pos, &len, &tmp))
+		goto out;
+	config->safe_mode = !!tmp;
+
 	if (read_u32(&pos, &len, &config->network.n_interfaces))
 		goto out;
 
diff --git a/lib/types/types.h b/lib/types/types.h
index 762530a..0333a02 100644
--- a/lib/types/types.h
+++ b/lib/types/types.h
@@ -121,6 +121,7 @@ struct boot_priority {
 struct config {
 	bool			autoboot_enabled;
 	unsigned int		autoboot_timeout_sec;
+	bool			safe_mode;
 	struct network_config	network;
 	struct boot_priority	*boot_priorities;
 	unsigned int		n_boot_priorities;