Tools: hv: cache FQDN in kvp_daemon to avoid timeouts
kvp_daemon does some operations which take an unpredicable amount of
time. In addition the kernel driver gives the kvp_daemon a 5 second
timeout to respond to message from the host. If an operation such as
getaddrinfo takes a long time and the timeout triggers then netlink
errors occour. As a result of such errors the daemon just terminates and
the service becomes unavailable.
Idendifying and fixing these shortcomings in the kernel-userland
communication protocol will be done in separate patches. This change
fixes just one obvious timeout bug.
Update kvp_get_domain_name to not return a value, better diagnostic for
the consumer of the hostname string, remove trailing newline in error
case, use snprintf to not overrun output buffer, get hostname only once
and return the cached result.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 8fd9ec6..21bd7d4 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -89,6 +89,7 @@
static char *os_build;
static char *os_version;
static char *lic_version = "Unknown version";
+static char full_domain_name[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
static struct utsname uts_buf;
/*
@@ -1367,7 +1368,7 @@
}
-static int
+static void
kvp_get_domain_name(char *buffer, int length)
{
struct addrinfo hints, *info ;
@@ -1381,12 +1382,12 @@
error = getaddrinfo(buffer, NULL, &hints, &info);
if (error != 0) {
- strcpy(buffer, "getaddrinfo failed\n");
- return error;
+ snprintf(buffer, length, "getaddrinfo failed: 0x%x %s",
+ error, gai_strerror(error));
+ return;
}
- strcpy(buffer, info->ai_canonname);
+ snprintf(buffer, length, "%s", info->ai_canonname);
freeaddrinfo(info);
- return error;
}
static int
@@ -1453,6 +1454,11 @@
* Retrieve OS release information.
*/
kvp_get_os_info();
+ /*
+ * Cache Fully Qualified Domain Name because getaddrinfo takes an
+ * unpredictable amount of time to finish.
+ */
+ kvp_get_domain_name(full_domain_name, sizeof(full_domain_name));
if (kvp_file_init()) {
syslog(LOG_ERR, "Failed to initialize the pools");
@@ -1671,8 +1677,7 @@
switch (hv_msg->body.kvp_enum_data.index) {
case FullyQualifiedDomainName:
- kvp_get_domain_name(key_value,
- HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
+ strcpy(key_value, full_domain_name);
strcpy(key_name, "FullyQualifiedDomainName");
break;
case IntegrationServicesVersion: