Re: [libvirt] [PATCH] daemon: add option to read host uuid from /etc/machine-id

On 04/25/2016 10:38 AM, Nikolay Shirokovskiy wrote: > Daemon config parameter switch between reading host uuid > either from smbios or machine-id: > > host_uuid_source = "smbios|machine-id" > > Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy(a)virtuozzo.com&gt; > --- > daemon/libvirtd-config.c | 2 ++ > daemon/libvirtd-config.h | 1 + > daemon/libvirtd.c | 38 +++++++++++++++++++++++++++++++++++--- > daemon/libvirtd.conf | 14 ++++++++++---- > src/libvirt_private.syms | 1 + > src/util/viruuid.c | 31 ++++++++++++++++++++++--------- > src/util/viruuid.h | 3 +++ > 7 files changed, 74 insertions(+), 16 deletions(-) > > diff --git a/daemon/libvirtd-config.c b/daemon/libvirtd-config.c > index 7a448f9..45280e9 100644 > --- a/daemon/libvirtd-config.c > +++ b/daemon/libvirtd-config.c > @@ -374,6 +374,7 @@ daemonConfigFree(struct daemonConfig *data) > VIR_FREE(data->crl_file); > > VIR_FREE(data->host_uuid); > + VIR_FREE(data->host_uuid_source); > VIR_FREE(data->log_filters); > VIR_FREE(data->log_outputs); > > @@ -463,6 +464,7 @@ daemonConfigLoadOptions(struct daemonConfig *data, > GET_CONF_UINT(conf, filename, audit_logging); > > GET_CONF_STR(conf, filename, host_uuid); > + GET_CONF_STR(conf, filename, host_uuid_source); > > GET_CONF_UINT(conf, filename, log_level); > GET_CONF_STR(conf, filename, log_filters); > diff --git a/daemon/libvirtd-config.h b/daemon/libvirtd-config.h > index 3e1971d..672e9ad 100644 > --- a/daemon/libvirtd-config.h > +++ b/daemon/libvirtd-config.h > @@ -28,6 +28,7 @@ > > struct daemonConfig { > char *host_uuid; > + char *host_uuid_source; > > int listen_tls; > int listen_tcp; > diff --git a/daemon/libvirtd.c b/daemon/libvirtd.c > index 7ec02ad..ca1ec7a 100644 > --- a/daemon/libvirtd.c > +++ b/daemon/libvirtd.c > @@ -1076,6 +1076,39 @@ static int migrateProfile(void) > return ret; > } > > +static int > +daemonSetupHostUUID(const struct daemonConfig *config) > +{ > + static const char *machine_id = "/etc/machine-id"; > + char buf[VIR_UUID_STRING_BUFLEN]; > + const char *uuid; > + > + if (config->host_uuid) { > + uuid = config->host_uuid; > + } else if (!config->host_uuid_source || > + STREQ(config->host_uuid_source, "smbios")) { > + /* set host uuid in lazy manner*/ How about /* smbios UUID is fetched on demand in virGetHostUUID */ > + return 0; > + } else if (STREQ(config->host_uuid_source, "machine-id")) { > + if (virUUIDRead(machine_id, buf, sizeof(buf)) < 0) { > + VIR_ERROR(_("Can't read %s"), machine_id); > + return -1; > + } > + > + uuid = buf; > + } else { > + VIR_ERROR(_("invalid UUID source: %s"), config->host_uuid_source); > + return -1; > + } > + > + if (virSetHostUUIDStr(uuid)) { > + VIR_ERROR(_("invalid host UUID: %s"), uuid); > + return -1; > + } > + > + return 0; > +} > + > /* Print command-line usage. */ > static void > daemonUsage(const char *argv0, bool privileged) > @@ -1295,9 +1328,8 @@ int main(int argc, char **argv) { > exit(EXIT_FAILURE); > } > > - if (config->host_uuid && > - virSetHostUUIDStr(config->host_uuid) < 0) { > - VIR_ERROR(_("invalid host UUID: %s"), config->host_uuid); > + if (daemonSetupHostUUID(config) < 0) { > + VIR_ERROR(_("Can't setup host uuid")); > exit(EXIT_FAILURE); > } > > diff --git a/daemon/libvirtd.conf b/daemon/libvirtd.conf > index d2c439c..eaae680 100644 > --- a/daemon/libvirtd.conf > +++ b/daemon/libvirtd.conf > @@ -410,10 +410,15 @@ > > ################################################################### > # UUID of the host: > -# Provide the UUID of the host here in case the command > -# 'dmidecode -s system-uuid' does not provide a valid uuid. In case > -# 'dmidecode' does not provide a valid UUID and none is provided here, a > -# temporary UUID will be generated. > +# host uuid is read from one of host uuid sources specified > +# in host_uuid_source. Possible values are 'smbios' and 'machine-id'. > +# First option will set host uuid from 'dmidecode -s system-uuid', > +# while second will read it from /etc/machine-id. uuid source > +# defaults to smbios. Other option is to specify host uuid > +# right here in host_uuid option, in this case host_uuid_source > +# will not be taken into account. In case uuid value in > +# smbios is invalid temporary host uuid will be generated. > +# How about: Host UUID is read from one of the sources specified in host_uuid_source. - 'smbios': fetch the UUID from 'dmidecode -s system-uuid' - 'machine-id': fetch the UUID from /etc/machine-id The host_uuid_source default is 'smbios'. If 'dmidecode' does not provide a valid UUID and none is provided here, a temporary UUID will be generated. A UUID can be manually specified with host_uuid, in which case host_uuid_source is not used. > # Keep the format of the example UUID below. UUID must not have all digits > # be the same. > > @@ -421,6 +426,7 @@ > # it with the output of the 'uuidgen' command and then > # uncomment this entry > #host_uuid = "00000000-0000-0000-0000-000000000000" > +#host_uuid_source = "smbios" > > ################################################################### > # Keepalive protocol: > diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms > index 2b55369..e5823b2 100644 > --- a/src/libvirt_private.syms > +++ b/src/libvirt_private.syms > @@ -2512,6 +2512,7 @@ virUUIDFormat; > virUUIDGenerate; > virUUIDIsValid; > virUUIDParse; > +virUUIDRead; > > > # util/virxml.h > diff --git a/src/util/viruuid.c b/src/util/viruuid.c > index 16e57db..721eac0 100644 > --- a/src/util/viruuid.c > +++ b/src/util/viruuid.c > @@ -231,21 +231,34 @@ getDMISystemUUID(char *uuid, int len) > }; > > while (paths[i]) { > - int fd = open(paths[i], O_RDONLY); > - if (fd >= 0) { > - if (saferead(fd, uuid, len - 1) == len - 1) { > - uuid[len - 1] = '\0'; > - VIR_FORCE_CLOSE(fd); > - return 0; > - } > - VIR_FORCE_CLOSE(fd); > - } > + if (virUUIDRead(paths[i], uuid, len) == 0) > + return 0; > i++; > } > > return -1; > } > > +int > +virUUIDRead(const char *file, char *uuid, int len) > +{ > + int fd; > + ssize_t sz; > + > + fd = open(file, O_RDONLY); > + if (fd < 0) > + return -1; > + > + if ((sz = saferead(fd, uuid, len - 1)) < 0) > + goto cleanup; > + > + uuid[sz] = '\0'; > + > + cleanup: > + VIR_FORCE_CLOSE(fd); > + return sz < 0 ? -1 : 0; > +} > + > This function needs a docstring, and I'd suggest calling it virUUIDReadFile or ReadFromFile But the idea looks fine to me, CCing Dan since he suggested the libvirtd.conf option - Cole