From 58125210ab3b202917c04fca014317944d464ea0 Mon Sep 17 00:00:00 2001 From: Olaf Hering Date: Wed, 7 Aug 2013 19:14:37 +0200 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- tools/hv/hv_kvp_daemon.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'tools') diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c index 8fd9ec66121c..21bd7d4574fc 100644 --- a/tools/hv/hv_kvp_daemon.c +++ b/tools/hv/hv_kvp_daemon.c @@ -89,6 +89,7 @@ static char *processor_arch; 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 @@ setval_error: } -static int +static void kvp_get_domain_name(char *buffer, int length) { struct addrinfo hints, *info ; @@ -1381,12 +1382,12 @@ kvp_get_domain_name(char *buffer, int length) 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 @@ int main(void) * 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 @@ int main(void) 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: -- cgit v1.2.3 From 269ce62bbc00c4e80bf3ca2aa21823f20625bcf6 Mon Sep 17 00:00:00 2001 From: Olaf Hering Date: Tue, 6 Aug 2013 20:55:38 +0200 Subject: Tools: hv: use single send+recv buffer send_buffer is used only once during registration. To reduce runtime memory usage reuse the recv_buffer for registration. Also use NLMSG_LENGTH instead of NLMSG_HDRLEN to take alignment into account. Signed-off-by: Olaf Hering Signed-off-by: Greg Kroah-Hartman --- tools/hv/hv_kvp_daemon.c | 10 ++++------ tools/hv/hv_vss_daemon.c | 8 +++----- 2 files changed, 7 insertions(+), 11 deletions(-) (limited to 'tools') diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c index 21bd7d4574fc..b8d6d541d854 100644 --- a/tools/hv/hv_kvp_daemon.c +++ b/tools/hv/hv_kvp_daemon.c @@ -1434,7 +1434,6 @@ int main(void) int pool; char *if_name; struct hv_kvp_ipaddr_value *kvp_ip_val; - char *kvp_send_buffer; char *kvp_recv_buffer; size_t kvp_recv_buffer_len; @@ -1443,11 +1442,10 @@ int main(void) openlog("KVP", 0, LOG_USER); syslog(LOG_INFO, "KVP starting; pid is:%d", getpid()); - kvp_recv_buffer_len = NLMSG_HDRLEN + sizeof(struct cn_msg) + sizeof(struct hv_kvp_msg); - kvp_send_buffer = calloc(1, kvp_recv_buffer_len); + kvp_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_kvp_msg); kvp_recv_buffer = calloc(1, kvp_recv_buffer_len); - if (!(kvp_send_buffer && kvp_recv_buffer)) { - syslog(LOG_ERR, "Failed to allocate netlink buffers"); + if (!kvp_recv_buffer) { + syslog(LOG_ERR, "Failed to allocate netlink buffer"); exit(EXIT_FAILURE); } /* @@ -1494,7 +1492,7 @@ int main(void) /* * Register ourselves with the kernel. */ - message = (struct cn_msg *)kvp_send_buffer; + message = (struct cn_msg *)kvp_recv_buffer; message->id.idx = CN_KVP_IDX; message->id.val = CN_KVP_VAL; diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c index 8611962c672c..8bcb04096eb2 100644 --- a/tools/hv/hv_vss_daemon.c +++ b/tools/hv/hv_vss_daemon.c @@ -140,7 +140,6 @@ int main(void) struct cn_msg *incoming_cn_msg; int op; struct hv_vss_msg *vss_msg; - char *vss_send_buffer; char *vss_recv_buffer; size_t vss_recv_buffer_len; @@ -150,10 +149,9 @@ int main(void) openlog("Hyper-V VSS", 0, LOG_USER); syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); - vss_recv_buffer_len = NLMSG_HDRLEN + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg); - vss_send_buffer = calloc(1, vss_recv_buffer_len); + vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg); vss_recv_buffer = calloc(1, vss_recv_buffer_len); - if (!(vss_send_buffer && vss_recv_buffer)) { + if (!vss_recv_buffer) { syslog(LOG_ERR, "Failed to allocate netlink buffers"); exit(EXIT_FAILURE); } @@ -185,7 +183,7 @@ int main(void) /* * Register ourselves with the kernel. */ - message = (struct cn_msg *)vss_send_buffer; + message = (struct cn_msg *)vss_recv_buffer; message->id.idx = CN_VSS_IDX; message->id.val = CN_VSS_VAL; message->ack = 0; -- cgit v1.2.3